Electric Exhaust Cutouts? [and other efficiency mods]
 

Hey! Didn't immediately find anyone talking about these things in searching.

I'm ordering an exhaust header for my truck this week (PSYCHED!!!!) and potentially a high flow manifold and muffler. I don't want it to sound like crap but a throaty sound and max efficiency are the goal.

Now, somehow on eBay I came across these electric exhaust cutouts.

Oh, I am too noobish to post images or links yet. Go on eBay and search for "electric exhuast cutout" or try some of these keywords "Electric Exhaust Cut Out Cutout Test Y-Pipe Valve Kit Switch".

It would be nifty to install in the back just prior to the muffler, for the sole purpose of having another switch in my interior... Switch of a button, goes instantly dragster loud.

My question is, in a relatively efficient exhaust system (high flow already) will I see a boost in MPG on the highway, or would the loss of backpressure pretty much work against me? Anyone tried these?

The only exhaust modification that helps fuel economy is when the cat and mufflers are deleted and the outlet is routed into the cab via a hole in the floor.

No.

If you removed the stock manifold and exhaust system, you have already removed the most efficient mpg system.

I realize u r a newbie....but do you realize you are a mpg site and not a hotrod site. Please use the search button and find the threads on exhaust manifold.

I am a newbie, yes, sorry but I did do some searching. I'm not hot rodding, but I was curious of your opinion of installing that. 90% chance I won't, and I did find threads on exhaust manifolds which I have been reading carefully, but there was no mention of an electric cutout system. Even if it's snake oil, worth discussing?

So what you're saying is that backpressure = efficiency? My truck has a really restrictive stock exhaust manifold that immediately goes into a cat and then to a 2nd cat, and then to the muffler. I was under the impression that I could get the long tube header that replaces the manifold right up to the 2nd cat and it should no doubt create extra power by increasing efficiency.

But you say if I modify the stock system I will not have increased MPG? Only time will tell, I will post my numbers very shortly. I have documented 100% of every mile I have driven my vehicle. If my numbers decrease, you are right.

but now in an imaginary situation, let's say you have a very restrictive stock system but you have a cutout like this right before the muffler and engaged it, you say I will be less efficient? If so, I will forget about this entirely.

It hasn't worked for anyone so far. And the physics don't back it up.

Maybe going to a straight cutout will cause a loss of backpressure and lose FE. But what about... a dual exhaust system, with the cutout allowing exhaust to flow to the 2nd muffler, which would be a higher flowing one. Has that been tried? Instead of going to lose all pressure, it just increases the flow... People say you can gain 1-2 MPG with a performance muffler, but they sound terrible. What if you could switch between the two?

cutout
 

In a past Cycle World Magazine article,a 'SMART' exhaust system was discussed for bikes.
The engines were operated on a dyno test cell and every conceivable transient engine load was analyzed.
Exhaust back pressure was altered throughout testing and a 'map' was developed for performance.
A 'valve-by-wire' (if you will) computerized system was developed in which closed-loop logic modulated a valve within the exhaust pipe ahead of the muffler,to always keep back-pressure in its sweet spot.
Back pressure is mandatory for low speed engine performance.Factory systems are 'tuned',and an alteration to the exhaust should be accompanied by an alteration to the induction.
I've run a couple of vehicles at Bonneville with bone stock powerplants and they do just fine at sustained WOT operation.And they get great mpg.Quiet too!
My opinion would be to leave everything under the hood alone until you've reduced your road load to a minimum with aero and rolling resistance.This is where your real savings are hiding.

You are bound and determined to open that thing up, huh. Who do you intend to bless with all the cacophony- people in town don't want to hear it, and people in the country don't either.

If you want to drive around and get good fuel economy, it probably isn't going to happen in a truck. I don't understand why that concept is so difficult for so many.

Interesting! Now hearing this coming from you guys I'm going to lean away from making her loud, if it affects the low end of the spectrum that much it will hurt my MPG goals. Still, I think I am going to replace the header... but leave the exhaust stock from the 2nd cat and back.

Will post a proper thread of it later, but basically my goal is to get my truck to be close to the same efficiency as my Honda Accord. It's apparently impossible I've learned as an SUV's shape is the biggest problem... now I just want to modify the engine to be as efficient as humanely possible. I was going to get a V8 Land Rover but instead opted for the 4 cylinder Suzuki Vitara 5spd, surely I would get better mileage. Nope, got about 19 MPG. worse than a land rover. Now after putting about $3500 in repairs on my Suzuki I can achieve 28 MPG, now for the very first time I get to plan an upgrade that ISN'T a repair, and I'm thinking exhaust. There has to be improvement to be made.

I will still get the header but on your stern recommendations I'm going to leave the rest of the exhaust stock! It is appreciated.

I never wanted to make it loud, just cheaper to drive. Good fuel economy in a truck is an oxymoron but I went for the 4-banger route. The problem is that at 100 kph it revs at just over 3000 RPM, I would probably be able to hear the exhaust on the highway, and it'll probably sound like ass. Not in my truck... but if for $200 I could install an exhaust flip to make it loud, I would do it. But if losing the muffler causes a loss in backpressure causing lower MPG it has not achieved anything.. when I look at fuelly and even on this forum for the MPG numbers on SUV's I'm already doing extremely well. Disturbingly well. I want to get 35 MPG though. That's the goal.

Can't speak for Winterpeg but cut-outs are illegal here.

Yeah, that's a concern too. That's why I want to retain the stock exhaust for driving around town... or at least, a stock-ish exhaust. About 50% of my highway drive is outside of the city. Mine's all rusty and it would be nice if they made an exhaust that was non restrictive and still sounded good.. Has anyone put two magnaflow mufflers in series?

While you can improve exahust efficiency, most off-the-shelf systems are tuned for mid-range to high-rpm use. It's not the lack of backpressure that's the issue... it's flow stagnation that is. A bigger exhaust is horrible at cleaning out the cylinders at low rpm. It's like trying to suck soda through a giant straw (say, for drinking smoothies?) slowly. Not easy.

The soda straw stock system usually gives you best flow at lower rpm... which is what you want for best efficiency at a cruise.

I could see an exhaust designed for efficiency, if you have the header designed for proper scavenging at low rpm, as Mazda does with their SkyActiv and its long-tube header systems.

But, as with Mazda, you would have to retune the engine to take advantage of this by leaning out (by leaning out the charge further). On an otherwise stock system, having the charge lean out due to better exhaust efficiency (and remember, you're still injecting the same amount of fuel... you're just getting more air with it) will cause feedback from the O2 sensors to encourage the stock ECU to inject more gasoline to fix what it sees as an unhealthy lean condition.

Like the guys say... focus on other stuff first if efficiency is the goal. If you want to improve fuel efficiency engine side, breathing mods can only improve economy by accident (read any debate on K&N, ever). The only sure way to improve economy is by retuning your motor with a chip or a reflash. And even then, the cost will most often outweigh any economy benefits.

Very interesting engine they have in the Mazda, I've never seen a more "straight" horsepower graph. They pretty much nailed it.

So you're saying in theory, headers = better but it's the ECU that is working against me. What if this is thrown into the equasion:

PSC1 (PDF) "RPM Piggyback".

Because there are guys on the SX4 forums who say they have seen an increase in MPG using the Piggyback. It looks to intercept the MAF sensor to dial in your air/fuel ratio to your liking. I've just discovered it, I haven't looked into it too much but the SX4 has a J20A and so does my Vitara so it's the exact same engine, if it helped I would buy one.

I think a combination of air fuel management and the header could increase better than the header alone, if that saw an increase. Or do we need a different device perhaps? Probably getting off topic at this point, but when you mention reflashing the ECU and proper tuning, is this outlandishly expensive if it were possible?

Humm... Either I'm confused, or you are. First you say you don't want it to sound like crap, then you describe everything you plan to do to make it sound like crap. Then you tell us you're working on a truck, but later say it's a Suzuki Vitara. Maybe you need to go back to square 1 and get organized :-)

Suzuki Vitara is a truck. It's an SUV, full 4x4 capabilities, I call it a truck.

True, I don't want it to sound like crap. That's why I was describing a scenario where I could hypothetically have two muffers on a switch, or an electric cutoff to go to zero muffler, so I could have a 100% quiet vehicle or a loud one, but you say it will not help MPG if I install something like that so that ship has sailed.

I don't want it to sound like crap but right now it's dead silent. All I can hear is engine. I want some sort of muffler system that is halfway to a performance exhaust, but since a company in Australia makes a long tube header that replaces the 1st cat, I think this will change the sound of the vehicle enough to leave the stock exhaust in there from the 2nd cat and back. To clarify, deleting the 1st cat.

It looks similar to this:

http://puu.sh/aOHVi/e5193ce055.jpg

^ that's 1 bank of the V6 model's manifold. The inline 4 looks somewhat like that, but 4 cylinders.

Here's what the header exactly is:

http://i.imgur.com/8OU97Pa.jpg

I know I described scenarios that make it sound like crap but only if they would increase or maximize efficiency. For example, two magnaflows inline to each other, they are a straight tube design and having two should sound quieter than one... The header should change the sound of it enough though. Now if the ECU A/F ratio is thrown off and there is a way to fix it...

You're right about the cutout thing though. I can't have two systems and switch for more efficiency, it's either tuned for one way or the other.

A cut-out requires you to have a y-pipe leading to the cut-out... which will definitely affect the laminar flow within the exhaust.

-

As for buying a piggyback for fuel economy, you have to do a lot of research. Many cars will "relearn" around a piggyback, adapting to the change in fueling parameters by altering the fuel maps over time. Which means you need an O2 sensor intercept, which will cost extra.

And the amount of money spent on a piggyback will often not be recovered through fuel savings. A piggyback that works properly costs a bit of money, as do the dyno-tuning or street-tuning required to get best performance (alternatively, you could tune it yourself, but that means spending more money on a wideband O2 and software).

Aero modifications will net you similar gains, for less capital outlay. Possibly even more if you go crazy.

And... driving habit modifications (which includes your choice of tires and daily tire pressures) have the potential to net you even more gains than that. If I recall right, some authorities claim gains of 30% or more are possible simply from driving habits.

Yup, doing a LOT of research on the subject, luckily there's a bit of data out there to work off of, pretty much all the answers are out there if you look hard enough.

If the piggyback costs $300 and will never recover that in savings that's fine with me. I really plan on this vehicle being "the one" that I carry for many years, I hope to own it a decade from now. I'd rather spend a lot on it now, but not willing to overspend needlessly. If the electronics for the piggyback end up costing $600-700 and they will perfect the gains of the header, it's worth it. But if tuning ends up costing $2000, I might as well have spent that in other areas.

Basically, I also have a 1993 Honda Accord. Bought it with 278k on it, drove it for a year or so getting 23-24 mpg in the city, loved the thing. Then I borrowed it to someone, uninsured, and there was a freak flood on that person street and the whole car was underwater for a brief period of time. Past the hood, halfway up the back of the seats. Basically it was a miracle to get it running again. Then it was basically just a beater, could barely even rev the engine to get the car to drive, getting 16-18mpg but I used it for 5-6 years like that, never really thought much about fixing it. Brainwave, the ECU is dead! I bought a new ECU and suddenly, the engine worked decently again. Got like 23-24 MPG again. Got new exhaust in 2012... Still 22 mpg.. Then we changed something. And it started getting 36 mpg. After all these years... I think it was the distributor cap.

Now, with 350,007.1 km on it, the car is physically shot. To demonstrate, here's a video of me amputating a section of rust that was falling off. The other side is just as bad, and there's a big horizontal split alongside the side of the trunk. Literally every part of the car is rusty. I don't know how long I could legally drive it anymore, but it's my emergency car if I need. Thinking about it though, the 72,000km I put on it, according to this mpg calculator, would cost $8,337 at 26 mpg and $6,021 at 36 mpg. I basically wasted 2 grand on my fuel car because I never really cared enough to fix up the problems.

So the Vitara comes into place in the winter, the tires on the Accord are completely bald, I have to drive highway speeds on sheet ice for half the year so I had to do something. I had the choice of $500 on tires or buy a new vehicle. I took door #2. I researched literally every vehicle on the market, I had to have a 5-speed manual and it needed to be a true 4x4 with the transfer case, something I could disable and have rear wheel drive all summer. I also needed it to be as efficient as possible, so a 4-cylinder would be preferred. I love the Vitara so much that when I saw there was one in the city I just instantly bought it that day. I didn't even look under the car, and.. it's already pretty rotten, I basically acted on impulse and should have looked for a cleaner one. My $2800 Vitara is now a $5600 Vitara with the repairs I've had to do to get it to this point. A lot of these repairs dramatically increased my fuel mileage, instead of adding power I'm just trying to get all that power back, and I'm almost complete with that. Fuel filter, spark plugs, diff fluid, and a couple other things on friday, then it will be basically as good as it gets. In a couple years I want to get the timing chain replaced and put in a new water pump, oil pump, and anything else that could theoretically hinder it's performance.

Now I'm at a point where I don't need to change anything, the truck just works and runs great. Now I'm thinking about actual mods, basically I want to plan on modifying/upgrading every component possible, but prioritize them in such a way that they are 2-3-4 years down the road and may not ever do them, but just to have a roadmap of what I want to do with it and be aware of every upgrade that I could theoretically purchase and install. Price determines priority in a lot of cases.

Now when I bought the Vitara it was giving me 20-21 mpg, now my last update was 27.3 mpg but city driving, it's probably easy 28.5 mpg if all highway. Every week or so spending $300-400 on it to try recover another 0.5 mpg is basically the plan. I think the thing will cap out at about 32-33 mpg before aero mods. With a few other mods I might be able to get it close to where my rustbucket Accord is now. It sounds like being a "modern vehicle" I won't have much to gain but there is. This thing has a mechanical fan on the engine, I'm swapping it for an electric and there is basically a guaranteed increase in mileage. Putting an thin belly pan plate under the body could help quite a bit too. I bet if I put $2000 more into the truck in specific areas I could come out at a net gain in 3-4 years. Plus that whole time, I have a very efficient truck that can haul ass in 3 foot of snow. Worth every penny.

Not particularly interested in skinny tires though! Rides good enough on stock sized rubber! Also, my driving tactics are already hypermile-focused. :)

Beyond the piggyback and header, any other power adder (aside from a turbocharger or supercharger) is incredibly marginal, so I'd stop there.

(well, who am I kidding, I would never stop... :D )

Beyond that, some good aero will help on a car the size and shape of a Vitara... as well as better lubricants. Small Suzuki 4x4s are typically crap on gas given the engine size, because the drivetrains are so heavy duty.

Aero mods would probably do be the most benefit, I would love to see what is available for an SUV. Premium lubricants will also go a long way, beyond that there isn't a whole lot left to do. Will certainly be looking for ways to push it further.

An older car wouldn't really adapt to the piggyback, with narrowband O2 sensors, no EGT sensors, and open/closed loop based off rpm the ECU is easily fooled.

For fuel economy increasing I don't think the tuning would be that difficult especially if you can use a switchable map (not that I'm saying this is easy to get in most cases) and use a wideband input. You can erase some of the emissions safety margin built into the top of the powerband by leaning it out to a more reasonable 0.85 lambda instead of the 0.75-0.8 on a lot of stock cars, and then lean out the cells in your cruising range to 1.2 lambda, and tweak the spark advance just a bit (since you're changing the low load cells there's already a lot of advance).

If you drive a lot of highway miles like many people in the US, the 5-10% fuel you'd save doing that could pay off the piggyback in under 2 years. A Greddy EMU is what, $800-900 with a harness? Unichips are less but I don't know if they're as capable. I think the EMU can run the injectors independently using a wideband input, and you can use a narrowband emulator to get the stock ECU to cooperate, since the stock ECU would then have no idea what the injectors are doing at all. A gas guzzler SUV/truck/luxury land yacht burns through several k in fuel in a year easily.

Looking for a 4x4 for my 15 yo for school and for me for weekends and a Vitara is on my watch for list, good to see it can get decent numbers.

Don't need skinny tires for better mpg, but a set of Nokian WRG2 or 3 might help when replacement time comes and do good in snow/ice.

The best thing for better mileage is to leave the stock engine stock. Don't mess with it aside from preventative maintenance. If there are any mileage gains by upgrading an engine, it will probably take a couple hundred thousand miles to pay back.

Tuners are usually the same way. You will pay $$$ and might have some gains, but is it worth it financially? It could take 1,000,000 miles to pay off a tuner. Plus, before and after testing is needed to prove the tune actually works, which means ABA testing in controlled conditions and swapping the tune back and forth. I am not saying don't do it, but tuning a modern fuel injected car is not worth it financially. It may be worth it as a hobby or for personal reasons.

As stated several times, work on aero mods and rolling resistance. Fuel consumption is directly related to how much work the engine is doing. More work = more energy = more gas consumed.

At 30,000 miles, an increase of 10% from 15 to 16.5 mpg will save $636 at $3.50 a gallon. We are also assuming that a good tune can get 10% more economy. I'd bet that figure would probably be more realistic at less than 5%, if there is any gain at all.

But, remember, not everyone can and should tune their own car. A bad tune can destroy an engine quickly. Tuning and dyno time cost money, so you can probably add another $500-$1000 to the $800-$900 tuning hardware. Now we are up to a $1,300-$1,900+ payback of almost 100,000 miles using the above numbers.

The manufacturers do a very good job of tuning and keeping engines safe. Leaning them out and changing the timing gives them less of a safety margin if there are weather changes, bad gas (lower octane), etc.

Sorry, but no. It's an SUV, not a truck, no matter what you want to call it. You can call your cat a dog all you want, but it's never going to bark :-)

Loud one = CRAP! In other words, you've probably got a halfway decently quiet vehicle now, and plan to spend money making it louder?

I agree, it's an SUV but it has the spirit of a truck. Everything about it is a truck except the shape. I wish this forum had another option besides "car" and "truck" for the defitions. Seems there aren't even many SUVs on here, period. They aught to be. They need help the most. I might casually call my Vitara a truck but that's because it is a cat that barks like a dog! :)

Re: the loudness.. I don't want it to sound like a Civic with a fart cannon on it. Not only is that just painful on the ears for passerbys, but also at high rev on the highway it would be louder than my stereo, depending on how extreme it is. But there are trucks out there that sound throaty and if you have just a slightest bit of exhaust noise it is nice. But being a 4-cylinder, I have to be careful, basically any exhaust sounds like garbage. So that's why I am leaning towards leaving the stock exhaust in place but replacing the manifold with the header, that MAY change the sound. Right now it's dead silent, like the quietest vehicle I've ever owned. Too quiet. I will post before/after videos of the header for you to judge, once I can find a dealer who will ship me the header.. eBay sellers are being unresponsive so far. There are videos of people who have taken this engine and put a magnaflow on it, but no one posting a video of the header AND magnaflow, so I am in slightly uncharted waters. Spending money to make it louder... only if in theory it is only slightly louder and improves performance, ever so slightly. Either that or I am going to buy a brand new exhaust that is entirely stock, but it's all rusty down there, I have to replace it eventually.

^^ this is the post I wanted to hear! I sort of want to get the Greddy.. whatever is best within reason. I need to find someone who can recommend EXACTLY what I should buy, right now leaning towards the RPM SplitSec Piggyback but those Greddy's aren't very expensive either. Not only would it pay for itself, but I would rather spend the extra money now to drive a more economical vehicle. Instead of buying a $15,000 land rover (which I almost did) I got the Suzuki with the intension of making it the most economical SUV possible. Maxing out the performance in the engine area is not even very expensive to do what I want, it's all under budget if I go "all out" with these mods. Plus it's better for the environment! Not always about money! :)

Yeah your 15 yo will forever thank you if they get to drive to school in a Vitara. Living in Iowa you probably see some cold and snow in the winter, I would be hesitant to let a NEW driver go out there with a 2 wheel drive car on icy roads. Having it in 4x4 mode is amazing, I've owned 9 cars before this Vitara and never a 4x4, driving in the winter is now fun. I even pulled a police car out of the ditch. That was when I had a lot of rusty components under the hood that was holding me back. I actually can't wait until it snows so I can rip through drifts again!

Good call on those Nokian tires. Guy at work bought them and swears by them. New tires are in the budget, I was planning on putting my decent-tread-life Michelins on some nice aluminum (but affordable) 16" rims and get a nice pair of VERY grippy winter tires for my steel rims.. but never thought about installing Nokians for year-round, I might just do that.

Another advantage in the Vitara you will find is that there are a LOT of them out there. Not "common" but you can find parts EVERYWHERE around the world. It wasn't just popular in North America, these things are in Japan, South America, Europe, and extremely popular in Australia. Not only can you modify them a bit, you can find cheap replacement parts, good aftermarket parts and solid advice out there.

I plan on leaving it as stock as possible, but still want it to perform better than stock. I know they are tuned very carefully and I won't see much gain, but I want to explore all options. Even if there isn't a gain in performance or economy, I like to buy nice things. Like, the timing chain... I don't know how old it is, but I hear it's wise to change. I plan on getting it changed next year. While the engine is all ripped apart, what else is there to swap? eBay kits come with water pump, oil pump, and so on. But each component is probably made by an aftermarket company, and there are probably better options out there that are better than OEM quality. If there was a timing chain that was physically the same dimensions but was $50 more because the metal was forged by an actual samurai and hand made, I would explore that option. Each moving part under the hood probably has 146,000 km on it and I'd like to replace each one with the highest quality replacement. There aren't many options from my explorations, so most likely just going to use OEM parts. So far I have only replaced parts that literally died on me, I haven't changed anything unnecessarily yet.

But there are unnecessary upgrades coming, slight ones at least. I haven't even looked at the spark plugs in there, they might be old or they might be new, but when I unscrew those coil bolts I want to know I have premium ones to put in anyway, they are like $50 for a good set and I am going to get those on friday. The gear oil in the diffs, might be okay but I am going to put in synthetic immediately, just to see the difference.

Another thing I spent like 10 hours googling for information was the gear ratios all over. If I could change the ratio in the diff to be lower, it would reduce my highway RPMs and thus save fuel. It seems to be geared a bit more towards towing than highway comfort. Still silky smooth, but I sure wish I could reduce it by 15%. Having front and rear diffs means I need to probably find a perfect mate, plus there are transfer case gears which could be theoretically changed, and the final drive in the transmission could be swapped, but of all my research I came to the conclusion that I can't just order something to put in. Not going to focus on it unless there is a clear choice.

Is it for a turbodiesel?
If not, then no.

Exhaust mods if done for economy offer some of the smallest gains.

It's not the TD, just regular gas.

I know it could be a small gain, but I was thinking I could have that option with the flick of a switch, but losing pressure in the Y-pipe is enough of a loss to scare me from trying it.

Not a diesel but I am going to locate the hood from a diesel. Look at that beautiful scoop:

http://i.imgur.com/CFU6UUk.jpg

I found the one I want, perfect condition and color, but $600 shipping charge.. Probably not going to be ordering that today..

non-restrictive
 

Before you buy something,you might consider taking the vehicle to a chassis dynamometer and have it tested under load with the stock exhaust,then with no exhaust,and see what the numbers look like.They can show you exactly what your engine and mpg are going to do.

Definitely worth the effort to test those numbers, and it would be a great source of information for any onlookers who are considering the same mods. Question I have is my vehicle ready for a dyno? I want it to be in tip-top shape, don't need a blown engine at this point in the game. With my Honda Accord I could do burnouts and rev it to insane levels (after the ECU was replaced) and just literally beat on it.. The Vitara I haven't ever revved past 4500 RPM, I'm driving it like a granny 99% of the time. Initially it just sounded like a bag of bolts when revving but now it sounds like it's back to a healthy state. I'd still want a pro to examine it before dynoing, that's for sure.

A dyno run isn't any more stressful than doing that run to redline on the street, as long as the operator is careful.

As for relearning, since it's an '03, relearning is possible. If you've got a piggyback unit that can run the injectors independently with direct input from the MAF, relearning won't hurt you... but otherwise, you have to take it into consideration.

If you've got something like the Split-second AFC or the Unichip, it's an issue. The Unichip has a feature to spoof the O2 sensor to prevent LTFT from drifting, and one to switch maps (if I recall right, my Q had four separate maps) when a trigger was reached (temperature, AFRs, etcetera) or when you flipped a switch.

One guy on our Mazda board with a Split-second got around LTFT drift using an intercept for the O2 sensor.

And yes, tuning it yourself is risky unless you know what you're doing. And dyno time ain't free.

Like I opined earlier... not worth getting for economy... but if you're getting it for the extra power, consider whatever marginal gains you get for economy (and considering an 03 will be OBDII, which already runs stoich at low loads and cruising, they will be!) as a bonus.

Myself the last place I'd look for gains is in the tune. OEM does a pretty good job IMO there, I'd attach everything else first, first reliablity, then reliablity, then good tires, then add a 1.5" lift but that won't help mpg wise, but it would help in the snow and looks good, then a winch.

I love quiet, if the exhaust is shot, I'd just replace it a the local muffler shop with about same as stock size and call it good, unless I could buy online cheaper, big pipe only helps at big rpm, normal driving doesn't need it.

I'm watching for a Tracker/Vitara but most of the newer ones around here (03 or 04) are v6, don't need a v6. The 2.0 4x4 5 spd 2 door hard top would be ideal, but rare, I'll settle for 2 door rag or 4 door if the price is right. My almost 15 yo already has 3 months driving under his belt, so for the 4 miles to school and back he'll make do fine with the Stratus just like his older sisters did (mom's at school also so can alway leave his car there) it really would be for me for weekends & just allows me to sell/junk the Stratus. Dragging deer out last winter sucked.

What kind of sucks is I can find similar year Explorers for almost 1/2 the price of a Tracker, with better interiors, probably better maintained, better everything, but mpg. But if I get something too nice my wife will want to drive it and not let me put dead things in back.

That combination of 2-door 5speeds are particularly rare. When I was looking, there was basically an unlimited supply of GV's with varying conditions, but only one with the 4 cylinder and 5 speed, this silky silver 4-door base model. I basically had to buy it :) since then I have only seen one or two 2-doors but they cost more, I could have probably looked nationwide and found one but having the 4 doors comes in handy from time to time and the seats folded down you have a HUGE cargo area. If I can afford it one day down the road, it would be cool to really restore and perfect the ultimate 2-door. Until that day comes, I will strive to have a moderately decent 4-door.

The V6 model might be ideal for some, but I agree it's overkill. I couldn't even consider that, I had a V6 or two in my day and the power is nice but it's not an ideal daily runner. Plus since it is designed with a V6 in mind, there is a ton of room under the hood with the 4 cylinder in there! As far as easy-to-work-on vehicles it's basically a best case scenario.

A lift would be nice, a 1.5-2" lift wouldn't have too big of an impact on MPG. Down the road it's something I would like to look into, but increasing winter performance already has priority: a set of winter tires and I want to replace the U-joints on the front driveshaft, I have the slightest vibration in 4x4 at high speed. Maybe all 4x4's are like this, but it's rediculously smooth in 2 wheel drive and in 4x4 it's not.. as smooth. I bet the U-joint has the whole 150k of mileage on it and it's a bit sore. I'm ordering all new U-joints this week and I will have from now until I need 4x4 this winter to install them.

You can use conservative "canned" tunes that will slightly lean out the highest load cells, which is extremely helpful to fuel economy for aggressive drivers because the factory tune is usually way too rich.

Leaning out the low load cells is done pretty frequently to save gas while cruising, and on less efficiently geared cars like mine you can definitely get 10% back just from the reduced pumping loss on the freeway. My engine runs at 30% indicated load on the freeway! The torque calculations work out to the engine putting out something like 13% of its available torque, and so it's gotta be running at like 400+ g/kWh BSFC. Highway cruising my car only does like 37mpg, when it has similar drag and RR to a Prius. Most economy cars are doing a bit better but any passenger car with a V6 or V8 is probably doing even worse.

Personally, a tune/piggyback would be one of the first purchases for me on my next car, because it both saves fuel and gets you more power (for relatively cheap compared to an exhaust or something too!), plus you get to fiddle with stuff like cam timing (the cam timing on some cars is set for more "response" and less efficiency).

So, I think the piggyback would be especially useful after getting my header, but it's rare and no ebay seller has returned my message about shipping yet. I'll get it eventually, but the piggybacks are available any time of the day. I'm really interested in getting one, potentially.. tomorrow or the day after. Looks like you have to splice into the car directly in a lot of cases -- I'm dedicated enough that I'm willing to go that far, but I have a plan. Since all I'm doing is intercepting wires that go INTO the ECU, I think I could just as easily buy a 2nd ECU and do the modifications to it directly. Basically, on the inside of the little pin connector there is a 90 degree elbow of metal, seemingly pretty thick, that I could probably cut and then run a small wire from each side to a hole in the side of the ECU's case. This way I could just unplug the modded ECU and put the stock one back at any time. My specific method of doing so I will put in a more devoted thread somewhere, but I would probably want to go the extra mile in spending the $50-60 on a spare ECU to save cutting any wires on the truck. I've installed mod chips on the tiniest circuits inside game consoles so soldering here will be no problem.

But I need your opinion of something. Alright, so, some people say I should get the wideband o2 and whatnot. Is this to basically know EXACTLY my air/fuel ratio at any given time? For like, really tuning it exactly the way I want? But what if I install the most optimum settings on the piggyback, the whole wideband setup isn't really necessary anymore, is it? Cool to play around with, but.. all I need are the right settings, if I am understanding this correctly.

So, roadracemotorsports.com has many products including some very specific SX4 tuning equipment, and since the SX4 also has the same J20A engine as me, I assume things will bolt on. I am not going to buy anything they carry except their piggyback, they keep recommending me to buy the overdrive pulley but I don't like the pulley's disadvantages. Reading online, 100% of people who have installed their piggyback is looking at a ~3 MPG gain on the highway, no complaints, no ECU re-learning, just a performance boost all around. They claim to have sat there tuning it with over 10 hours of dyno time and have perfected the J20A's A/F ratio map. It could probably be pushed a little further in either the economy or performance direction, but whatever software they have come up with is probably the best all-arounder. So I could probably just use their piggyback and not install the wideband o2 (or at least, not initially). I asked them and they said yes, their software will work great on the Vitara's J20A: "Basically the pulley system and the piggyback ECU will work there. It does make a good difference in power and even economy. WIring it in is easy. It is just a matter of knowing the pinouts on your car. WE will give you instructions for SX4 and you adapt from there."

So, pretty much guaranteed that it WILL work, and the tune should be pretty much bang on being the same engine, but I can get the part itself elsewhere for over $150 less. On the website the picture is photoshopped to not show the logo (??) and it looks like they just put a sticker on it. I could just save the $150 and buy the actual part they send me, but tuning it myself might lead me to buy a $200 wideband o2 sensor, and probably would never get a map close to theirs, dyno time would probably cost more than the whole piggyback. If theirs is perfect, the software is worth the cost difference. What would you do? Can I extract a copy of their software from the unit and then later make small adjustments to it? If so, I think it would be wise to have their software as a base-line. Unless I can just obtain a copy of a good AF map. Then there isn't much point in spending the $150 extra on theirs?

Everyone that buys a tuner gets an MPG increase...don't believe everything you read unless they are offering up some detailed before and after testing.

And never, ever, ever, believe the claims of the people selling the product. They are salesman trying to make money. YOUR money.

I agree and disagree.

I agree that people are shady as hell. On the product page, they have the text "See Dyno Sheet note the stock fuel curves wasting fuel!" and if you click it, [url=http://www.roadracemotorsports.com/images/SuzukiDynoRRM.jpg]here is the image[/img]. Holy smokes, a +15HP gain! I was sold immediately. But I examined it very carefully, in the bottom it says the blue line is "baseline" and the red line is "cold air, exhaust, pully". That doesn't even mention the piggyback at all. This before-after dyno result could very well the the same car but there is nothing to say they even installed a piggyback on it. Why would they even post this? That, the photoshopped images, sticker on the product's casing, and a few dead links on their website have made me aware that they are not perfect. But, they might know engine tuning. There is a chance that this is better than stock. Spare ECU, modified with this piggyback wired in, if I insert it to my stock system it MAY increase my fuel economy. It's worth a shot, even if it only helps slightly. I will not be using their sales tactics to convince me, I'm using the general public, and reading every user who buys it, specifically from them, and the success they have been having. Everyone is raving about it. People are going from 28 mpg highway to 31 mpg highway. Even if it brought me up to 29 mpg, it's technically better than stock.

On the product page: We have maximized the fuel curves to better take advantage of basic mods like intake, header and exhaust. Regardless of mods, this Piggyback unit will increase h.p. for any N/A SX4! It is also proven to INCREASE GAS MILEAGE. .

So reading that they have designed their map to consider headers and exhaust, I think it will be more appropriate to have their piggyback installed once I have the header. The highway MPG numbers before and after the header will be interesting but also before and after the piggyback, and if I have the modded ECU in such a way that I can swap it out any any point, I can show you all 4 of those scenarios. And once I play around with it a bit, maybe I can tune it further. Step one is deciding which path to go down, but I'm thinking 80% likelyhood I will buy it from them, even if there is a bit of bogus going on. That's the plan currently.

However, it isn't the only option. Sure they have tuned that specific piggyback to 100% of it's possible capabilities, and it works just great and gives me what I want, but there are a dozen options for the same task. Look here and there are 9 different A/F controllers, "split second" is just one of them. The 10th option, however, is the most interesting.

There's a company, Dynotronics, that reflashes your ECU to the ultimate settings, and actually I was reading online and the '03 Vitara is compatible with OBDII-port reflashes, it doesn't have antitune. Instead of buying perfected $250 part for $400, this is a $500 piece of software on your existing ECU. This is a scenario when having a spare ECU is handy. This make me want to have a stack of ECUs... Going to the junkyard on Saturday, there are 5 of these trucks and there's a guy who has a half dozen parting out, I bet I can get spare matching ECUs pretty easily.

"It's a well sorted daily driver tune - meaning it has gone through extensive testing and tweaking and is NOT just a WOT remap. It is a completele ECU reflash, not a chip. You can expect a 2-3mpg gain at minimum during normal driving. Expect 8-10% power increase with a completely stock car, more with a car with exhaust/intake work. If you have a datalogger and want to really dial in your tune, they are more than happy to send it back as many times as you want to get it perfect (shipping at your cost). This means if you ad a header and exhaust or even an intake system down the road and want it retuned, just send it back at your cost and they'll dial it in for you."

So, interestingly, it's bascially what I want. Looks like they even have discounted it to a point where it's close to $400, just a tiny bit more than the piggyback would cost me. So both roads are going to set me back similar amounts.

In this thread, they try both that EXACT piggyback tuned from RPM and the performance tune of the Dynotronics. The even took the two dyno sheets and laid them on top of each other, blue is the ECU tune and the red is the piggyback:

http://i.imgur.com/KdyUt2W.jpg

Here's the air fuel map for the same test. They are totally different.

http://i.imgur.com/2r9YT9f.jpg

They are basically saying the Dynotronics is better. What are your thoughts?

If you want to spend your money, then spend it, after all, it is your money! You already have it spent in your head anyway.

But, if you want to get better mileage, then don't buy anything. You don't need to. You only need to mod the driver as a first step.