How to build a muscle car for better fuel economy?
 

https://ecomodder.com/forum/attachme...1&d=1545931924



In the not too distant future, I plan on modifying my car's second-generation LT1 motor to make it a better daily driver with emphasis on shifting it's stock torque curve down to lower RPM range, where the car spends most of it's time in city traffic. Now, I don't race this car and I have no plans on taking it to a track, I even drive this car in the heart of the winter in decently deep snow! So, this is where I have to balance power production with fuel economy, which I would prefer to maintain with the given EPA estimates. The automotive performance forums are only so helpful since those guys specialize in building race cars and not the opposite side of the spectrum where I am at.

So, as a starting point for my build goals with my LT1 motor, I am very set on modifying a Tuned Port Injection intake manifold to fit on my LT1 heads, to use AS&M big runners and to have the plenum, runners, and manifold bottom port matched, gasket matched, and extrude honed. I plan on using 180cc DART heads since they emphasize port velocity, which is great for low end torque production and in my mind, helps in overall fuel economy. I also plan to use long tube headers designed to emphasize low end torque which are customized to work with my emissions devices and will use catalytic converters. Also, for the sake of better efficiency, using Iso-butanol fuel to allow for a higher compression ratio of up to 12, equipping my motor with smaller low friction bearings, piston skirt/bearing/valve stem/valve spring/crankshaft low friction coating, low friction crankshaft seals, and a true roller timing chain.

The last modification deals with the camshaft. After some research I found that the widest lobe separation is the most optimal for fuel economy, and such a lobe separation at 117 is what I have for my stock camshaft. I am left wondering if there is anything I can possibly do to improve upon the stock camshaft profile, increasing the lift for any marginal performance gain without sacrificing fuel economy. I do think the stock camshaft should be advanced to help improve the lower end torque that my car really needs, but again, I only have so much help using other forums that don't specialize in what I wish to achieve with my muscle car and daily driver.

So, what do you any of you think about these ideas to modify my second-generation LT1 motor for better fuel economy and a good enough increase in the "seat of the pants" performance.

Easy, spend lots of money.
More on the rest of the car than the engine it's self. You will need a 6 speed to get good fuel economy and get up and go performance.
Add an oil to coolant heat exchanger to get the oil up to temperature.

I have owned a 1972 Chevelle, a 1972 Nova and a 1969 Camaro a very long time ago. Most of those cars got around 15 MPG and all of mine were bone stock except the 1972 Nova had a lower rear end gear swap at some point before I bought it. Someone was trying to make that Nova faster off the line and it was. The 1969 Camaro had a 327 with an automatic trans and tall rear end axle gearing. I remember running 130 MPH and it was turning 4,000 RPM at that speed with plenty more to go. None of these cars got fantastic gas milage, but the Camaro got the best with it's tall rear end axle gearing.

When you tell me you want to modify your LT1 motor I am going to guess any dealer non stock parts available for that engine are mostly performance mods.

To me to save gas with that car is going to require getting the RPM's of the engine down while you are driving it. You are not wanting super low gearing in the rear end axle if you want better gas milage. Lower gears cause higher engine rpm at any road speed. Your car might be fine as is depending on what gearing is in it already.

You can change rear end axle gearing and rebuild transmissions to achieve whatever you want with a Chevy/Pontiac. Lots of things you can do with a Chevy product because there are tons of parts made for Chevy cars to change whatever you want about the car.

To make my post FUN I am going to suggest you check out a car built by a guy who goes by the name of Speedycop who races in the 24 Hours of LeMons races. They race $500.00 cars in that race. Check out the Speedycop Bonneville Donk description why the build got better gas milage and then scroll to the bottom of the page to see some of the other cars he built. Speedycop has built incredible cars for that race. Here is the link:

The Greatest 24 Hours of LeMons Cars of All Time - Roadkill

What would be the advantage of using iso-butanol? Is ethanol out of question?

You could possibly increase the compression significantly more (e.g. 16:1) and run an Atkinson-cycle; to do this, you'd give the intake valve longer duration, and advance it to the point that it stays open partway into the compression stroke. It's easier to do this on engines with variable cam timing, because the fuel economy improvements come at the expense of power, and variable timing would allow you to switch it on or off at will. This is one of the tricks Toyota and Hyundai's hybrids use to get near 60mpg, and the loss in power is made up for by adding an electric motor to add torque down low.

On that note, I wonder if you could retrofit a servo or somesuch that would allow you to modify the cam advance on the fly, so you could get the best of both worlds - Atkinson while cruising, and OTTO while accelerating. You wouldn't be able to run astronomical compression, but you'd still see gains.

Other than that, you could play with the heads and see if you can get a stratified charge, to allow for leaner operation. My Insight is able to lean out to over 24:1 AFR on the highway, giving it diesel-like efficiency.

Other than that, taller gearing will probably make more difference than anything else.

Are you in NYC or some other city in NY? Is a bicycle or bus out of the question?

F-bodies usually came from the factory with 3.20-ish gears I think: light weight, good aero, and good power enabled GM to run tall-ish gears to squeeze out a little better highway mpg. For city driving a rear ratio change won't help much. Plenty of heat under the hood, make up an adjustable WAI and monitor temps on a scangauge. Most exhaust manifolds sucked before 1990 but I'm not sure if the LT1 manifolds perform like other SBC manifolds of the past or if they were a shorty design like the LS1 manifolds, so gains could possibly be made by switching to headers. For Stop and go driving, weight reduction can help so you need less power to take off.

Best way to save gas is by not burning any but EOC and the 4l60e are probably not going to play well together.

My Trans Am is already a 6-speed. I could not possibly imagine trying to drive this car with an automatic in the heart of blizzard conditions, you would spin out into a guard rail/cement block or act as a crooked thrown bowling ball headed for "pins" in the opposing lane of traffic. Not good!

The only issue with an oil-to-coolant heat exchanger is that in below freezing weather the engine oil will likely warm up faster than the coolant, which takes a good amount time to get up to temperature while letting the car idle for 15 minutes. :snail:

Well this is where my logic comes in with regards to using a small block chevy TPI intake, optimized for low to mid-range torque production for daily driving performance, from the 1980's, on my 90's LT1 with the TPIS miniram intake copy from GM, which is designed to optimize high end RPM torque, for racing! I can't tell you how many guys suggested I use lower gear ratio 4.11 to get my motor operating at a higher RPM level. This is great for acceleration and it solves my torque problem but it will kill my city mileage. Furthermore I don't have the opportunities to safely drive my car at RPM ranges above 5000 to "enjoy it". So, I have consigned myself to enjoying the cruise at lower RPM and hearing the exhaust tone from the V8 with Magnaflow cat-back exhaust!

For safety, my stock 3.42 gear ratio from GM is optimal for daily driving, bumper-to-bumper, stop-and-go acceleration speed. For fuel economy, my 3.42 gear ratio is optimal enough! I could probably go higher with a 3.23 gear ratio but the 3.42 seems good enough. So, instead of trying to make my car operate at higher RPM, I am looking to the L98 and the TPI intake to help me make my LT1 behave like it's predecessor, having lower end and good mid-range torque, BUT the car starts to starve for air beyond 4500 RPM due to the long runner intake manifold. However, this would work for the sake of fuel economy at higher RPM so this system is perfect for my daily driving needs, which is why GM developed it in 1985, for fuel economy/emissions standards of the time and for optimal daily driving!

Ethanol is out of the question! Butanol has a higher burning power than Ethanol. Butanol has 105,000 BTU, Ethanol has 84,000 BTU, and straight gasoline has 114,000 BTU, per gallon. Right off the bat, you are burning less Butanol than Ethanol to achieve the same power of gasoline in the same motor.

Second, Butanol mixed in gasoline does not undergo phase-separation, unlike ethanol. Butanol can be used up to 100% in a gasoline motor without the need to modify the engine. Ethanol is very corrosive and can only be mixed with gasoline up to 85%. Any motor using 100% Ethanol will have required extensive modification and will still not have the power production or fuel economy of it's gasoline equivalent and compared to the same car using 100% n-butanol or iso-butanol.

Iso-butanol is the 102 octane version of normal "n-butanol" with an octane rating of 87. So, I am forced to use Iso-butanol for my V8 motor!

Unfortunately, I don't have the budget of General Motors to conduct the Real McCoy research and development to really turn this "obsolete" motor into a truly fuel efficient and superior version of it's former self. Besides, with all the newer technology out there from variable-timing to direct-injection and direct-ignition, and cylinder deactivation (!), for the money I would spend to go nuts on an engine design over twenty years old, I would be better off swapping a 2014 LT1 into my Trans Am. However, with all the work required to make such an engine work with my factory gauge cluster, the computer required by this engine, and all the wiring from my existing 1990's equipment to work with the 2014 computer for this motor, it is more cost effective to salvage my existing motor and improve upon it with existing parts and coating.

The biggest problem is reducing internal friction, that is easily solved with the new anti-friction engine coatings that are now sprayed on the motors. I can have this same coating sprayed on the motor parts. I already use full-synthetic motor oil so this is one step in marginally increasing power output and increasing fuel efficiency! The other steps involve lower end torque production which, if the car can start moving from a dead stop easier thanks to lots of torque on tap, this helps in overall fuel economy. If I can drive the car mostly under 2000 to 2500 RPM, with full manifold vacuum, this all ties in to better fuel economy.

Butanol is a great gasoline replacement, but where do you get it from at a good price?

Since you have a manual, focus on EOC and less on engine mods. You're doing more idling than anything so start coasting a bump staring. Making better torque is nice but weight reduction is free if you can stand to lose carpet, useless back seats and other panels. Get a light weight battery or switch to those fancy super capacitors. You're rack and pinion right? Delete the PS pump and loop the lines. What kind of smog pump do you have? Can you delete it and stay DOT legal?

I have found that unless you have an oil to coolant heat exchanger the oil takes a lit longer to warm up.

Well I plan to contact GEVO, the company that is promoting this variant of bio-butanol, and see what can be done. In all honesty, I highly doubt that I will be able to get it for a competitive price to the pure non-ethanol gasoline I am currently using. Since Iso-butanol is not being sold at any fuel station in the country, I will likely have to purchase it by the 55-gallon drum and have it shipped to my house. From there, purchase a hand pump to suck out the fuel from the drum and fill up my car.

This is REALLY the only way to start getting this product on the market, people willing to spend the money initially to consume this product and start driving a demand to have it sold from a retailer.

My only incentive to use this fuel over cheaper gasoline is the knowledge that I am using a cleaner burning fuel and a fuel that will keep my motor running clean since it produces negligible amounts of carbon deposit. I don't expect any payback in using this fuel, but I do intend to promote it with my car as I drive around town.

Again, I need to see what the final cost will be and decide on whether or not it is worth it. Maybe GEVO can cut me a deal if I am a year-round customer, who knows.

I am not going to go crazy by trying to shed as much weight from my car as I can. There is only so much I can possibly do to my motor to make it more efficient than the efficiency that GM was able to achieve back in the days of research and development during the mid-to-late 1980's. Even then, after all my modifications, I may net a marginal fuel economy increase that is far from stellar, but at least I will have net some gain and with all the reduced friction inside the motor, it should have a marginal power increase as well, paired with the compression ratio increase.

I won't even play games with shutting off the motor and coasting down hills. One guy on the performance forums suggested I have my stock computer tuned to shut off fuel delivery whenever I use the motor for braking, like a jake brake, since I have a stick shift. I am not sure if this is even possible but it would help with unnecessary fuel consumption at higher RPM and no throttle!

I will have to research it but it is hard to believe. The motor oil is cycling through the motor long before the coolant starts cycling through after warming up, I don't see how it is possible for the coolant to warm up faster than the motor oil...

It's been shown on this forum that DFCO (deceleration fuel cut off) is less efficient than coasting in neutral so no real need to add DFCO; you're better off staring to coast in neutral earlier instead of relying on the engine to slow you down.

I would be very interested in a drum of this for testing on my car. When you find out could you please let me know the cost for a 55 gallon drum? Thanks.

Most vehicles I owned will allow me to put my hand on the oil pan if I stop as soon as the coolant is up to operating temperature on a cold day.
There are at least a few posts on here talking about oil to coolant warm up times on exchanger less systems.
On a vehicle that does not have a heat exchanger or cooler the oil can get hotter than the coolant by up to 20°F, but it takes a while.

I'm putting together a 454 bored and stroked out to 489 with 11:1 compression. Instead of running expensive fuel all the time I am going to try to run regular unleaded and then have cheap water methanol kick in when I get on the throttle.

My driving style incorporates both. Depending upon driving conditions I take my dear sweet time braking for a stop light or congested traffic ahead of me by pushing in the clutch and lightly, featherly, applying the brake with added increments of pressure until I am at a full stop. I drive like I have air brakes and am hauling a trailer. This gives traffic behind me ample time to be alerted to stopping traffic ahead if they are the type who don't pay attention when driving and like to ride your bumper dangerously!

There are times when it is safer to use my motor for braking to slow my car down more efficiently than the brakes, this is usually on the expressway but even going thirty miles an hour and making a turn I can squeeze in a downshift. So for conditions such as this, I might as well have my stock computer tuned for deceleration fuel cut off! The name of the game is optimizing fuel efficiency and pinching it where I can. I even suggested trying to tune my car to idle as low as 500 RPM, if possible, or as high as 700 RPM, to maximize fuel efficiency for those long idle periods I will end up facing in traffic.

Well, that could be a few years out. Right now I am unemployed by choice and going to college for a career change, so I don't have the money in my savings account to splurge on this fuel. All you need to do is e-mail GEVO, get in contact with a business agent, and talk about options, pricing, and how to go about it. That is what I have planned when I am earning a paycheck finally.

Okay, so you are using the exchanger to cool down the motor oil to help cool down the motor. Hmmm, I need to research it. I am not so sure I even need it, especially for the motor oil that I am using.

There are 2 different kinds of oil coolers.
Oil to air.
Oil to coolant.
The oil to air just keeps the oil from overheating.
The oil to coolant heat exchanger actually regulates oil temperature, that's why all heavy duty engines have them.

The question then becomes, do I really need one for my application? It could be beneficial if I were to use lower viscosity motor oil than my recommended 5W-30. The lowest I could go is 0W-30 but I am not sure if this is too thin of motor oil to use in my motor, even with an aftermarket low friction ceramic coating of the motor internals and even if I am using top tier Amsoil Signature Series or the European Formula, and changing it out every 3 months like it were conventional motor oil.

For me, this is like a quest to see how far I can improve upon my "obsolete" motor, but it is worth it in my eyes. I don't race the car, but for a daily driver, improving the fuel economy while retaining the fun factor of having a V8 motor is the goal. This is where low end torque on tap comes in to play while using a very small camshaft for fuel efficiency.

I wonder if anyone can chime in on the selection of parts I have in mind for this build...

Will you be driving get short trips?

The car is a daily driver. Average driving time is 30 minutes in a mix of city and highway. Sometimes I have sat idling in backed-up traffic for more than ten minutes and a half hour trip could turn into an hour or more! On rare occasions, the car may take a cold trip two blocks to the store and back. Why?

Oil to coolant heat exchanger is ideal for short trips.

I have no experience with any alcohol fuel other than ethanol, but it tends to work better with a more accurate temperature control. Not sure about iso-butanol, but it may eventually benefit more from an oil-to-coolant heat exchanger too.

Well, it is something I will have to consider then when I have the motor totally overhauled. Thank you.

This youtube video is what started my research on butanol years ago. However, it wasn't until much later when I realized that normal n-butanol was too low in octane number for me to use in my V8. The only saving grace was stumbling upon GEVO with their "iso-butanol" which has a higher octane content, perfect for my V8 and perfect to increase compression ratio! A cleaner burning fuel with better combustion efficiency will yield better fuel economy when the motor is tuned appropriately for these changes.

From what I learned, Ethanol requires modifications to the motor to allow 100% use whereas Butanol does not require such extreme modifications albeit a minor change to the air-to-fuel ratio but as a stand-alone pump fuel to mix with gasoline, you won't have problems using it in an unmodified gasoline motor.

https://www.youtube.com/watch?v=s09ujb35w4s

The coolant surrounds the combustion chambers, it is there specifically to absorb excess heat of combustion, the oil will touch parts that get pretty hot, but not hot enough to warm it up quickly. The oil probably warms up the quickest when it is in the heads, but it isn't there for very long.

First of all, you seem to care about your car a lot, but letting it idle for 15 minutes is not doing your car any good. When you idle, ESPECIALLY when it is cold out, you are diluting the oil with fuel, which destroys the capability of the oil to lubricate. Get a block heater, plug it in a few hours ahead of time, unplug, start engine and start driving. I have a block heater that I use any time I drive the car when I have at least half an hour of warning. It is truly awesome to start your car in 30 degree weather and already have the coolant at 80 degrees. I even use my block heater when its 80+ degrees out. Coolant temps start out around 110-120, and the engine idles smooth and at 700rpm instead of 1000.


There is no reason to change your oil out every 3 months unless you are doing an F-ton of short trips, especially using Amsoil's signature series. Oil does not deteriorate over that short of time. I did an oil change after 10K miles and 19 months on my accord using Penzoil Platinum 0W-20, here are the results.
Attachment 23311

I do care about my car, but my ever improving maintenance has been the result of learning from mistakes with poor maintenance. So, with regards to my anal three month oil change interval, well, there is a reason for it!

I have thought about a block heater for my LT1 come the day I get the motor and entire car overhauled to like new. The problem is, I won't be able to hook up a plug to the car where I park, and I certainly can't run an overly long extension cord when we get deep snow! Furthermore, at work, I can't ask the company for an overly long extension cord to be able to use the block heater on my car while it sits for eight or ten hours in the frigid cold! So, this is where the block heater idea won't be so useful for my situation! This is why I am using Amsoil motor oil and changing the oil every three months! Just because the motor oil can last a year before requiring a change doesn't mean you should wait that long, and once the oil turns dark brown, you have to change it, high quality expensive motor oil or generic motor oil!


Even so, when I saw how black my motor oil was after literally waiting a year to change it using Amsoil Signature Series, it was disturbing! Furthermore, I was using 0W-30 motor oil when my motor called for 5W-30. I am not sure if I was doing harm to the motor or not by using a motor oil much more thin than was called for. Suffice it to say, one bad winter later, having a cracked radiator and overheating the engine, possibly destroying the head gaskets, I had lost oil pressure and I needed to replace the motor with a remanufactured version. So, BELIEVE ME I am going to be anal on maintenance and I put my order in for tire chains so that I don't have worry none about trying to drive uphill in snow that my car loses traction and momentum in!

Now, I just need to figure out if a tow version of my LT1 camshaft with a lobe separation of 111 will be alright for my application. They say lobe separations of 117 are better for fuel mileage but the tow cam version is spec'd to perform the same as my LT1 with lobe separation of 117, it just produces the torque sooner rather than later in the RPM band.

I sent in an oil sample from my Insight to Blackstone Labs at 10k miles, and mentioned I was concerned by how black the oil was. Their response was:

"It may appear dark, but that just means it's doing one of its many jobs. In this case, that would be 'cleaning'. The oil is capturing dirt and combustion byproducts so that it's removed when the oil is changed."

They suggested that based on the wear materials found in the oil, there was no unusual wear, and that there were still plenty of detergents and wear additives left, so I could try a longer oil change interval.

So, in other words, color is not a good indicator of whether your oil needs to be changed. And, I have reason to believe this, since I have 225k miles worth of 10k oil changes, and compression is still within margin of error from what it should be from the factory.

EDIT: Given how frequently you're changing your oil, you stand to save real money by getting an analysis done by a lab. You may find out (just as an example) you can go 15k miles / 18 months safely, in which case you can still very conservatively change it at 10k/12m. Base your decisions on real data!

Instead of starting and running for 15 minutes, get an oil pan heater and a coolant heater and hook those up. Wire them together so you just have one pigtail to plug in and set up an outlet on a timer in your garage (I hope you have a garage). Set the timer to energize the outlet an hour before you leave in the morning, and when you go to fire the car up it'll be halfway to operating temperature already, with no fuel wasted.

If you don't have a garage or at least a nearby outlet to hook up to, this suggestion is moot and I apologize.

I see you're willing to really dive into the deep end to make your fast car a thrifty car, and I strongly recommend you dig into PGFPRO's threads on what he's done to make his Eagle Talon a penny pincher when he isn't burning rubber at the strips. A lot of what he's doing engine-wise won't help you much, he's a turbocharging maven but when it comes to tuning, I think you and he could see eye to eye on a lot of stuff. For one thing, he's burning nontraditional fuels and for another, he's dug deep into lean burn in a car that never had it before. If you're willing to jigger the numbers on your ECU you could do similarly.

There is always lean burn for cursing.
That's worth a 10% to 20% boost in fuel economy according to my own testing.

Well, I would be afraid of possibly melting the pistons and doing horrible damage if the car is set too lean, this added to if I can increase compression to 12 using the Iso-Butanol I plan on using in the future.

I think fuel deactivation for deceleration may be the only trick I will be tempted to use to help improve fuel economy. Aside from this, I have to test the theory on better low end torque to permit very low RPM driving for fuel economy.

I am not expecting to have the mileage rating of a four cylinder car, but I would like to approach or meet the EPA fuel rating of the 2014 LT1 in the Corvette!

Well, what helped me to make my decision about changing the motor oil every 3 months was seeing the inside of my heads after my motor broke down and I was forced to buy a Jasper remanufactured motor. My stock LT1 heads were so coated in black deposit and dirty that it was amazing that I had not noticed it while driving, and this was using Amsoil 0-30 Signature Series! I slowly began to lose oil pressure over the years although I didn't notice until my needle one day dropped to zero. I got a manual oil gauge to verify that it wasn't just a malfunctioning gauge but my motor oil pressure was too damn low! I played as much of a role in the failure of my stock LT1 motor as did having too old of a factory radiator with a crack that I was unaware of bleeding off my coolant and leaving a massive air bubble in the system, overheating the engine and doing further damage with time...

It don't matter if the motor oil is tested by a lab to still be able to provide lubrication with carbon deposits in it, you still have carbon in the motor oil and you have gasoline and they are slowly working to alter the chemistry of the motor oil to make it more acidic which damages gaskets, and ultimately becomes more abrasive. I will never allow my motor oil to get as pitch black as I was used to seeing it! One year is INSANELY TOO LONG to change motor oil, let alone 18 months! I refuse to let my motor oil get that bad, not with my newish Jasper motor!

The mechanics and engine builders in the know use conventional motor oil and change it every 3 months and their engines have lasted beyond 200,000 miles and they are so clean on the inside! My stock motor didn't even last 100,000 miles and it was PITCH BLACK AND DIRTY on the inside! Nope, no lab will tell me it's okay to keep the motor oil in my car longer than 3 months...hell no!

Easiest way to improve city economy is a kill switch, and run the engine is little as possible. Kill it at traffic lights, while coasting, etc. and you'll get considerably more benefit than improving the engine's efficiency.

Perhaps you had a malfunctioning EGR?

This is a picture of my motor at 220k miles, having used 10k oil changes, generally 12-18 months apart:

https://i.imgur.com/L7DCspa.jpg?2

You could do all that.

I think you would see the most benefit if you make it a mild hybrid. And you could do it with GM parts. :thumbup:

http://ecomodder.com/forum/showthrea...tor-35003.html

HaroldinCR hasn't posted in the last month, but he's working in the jungles of Costa Rica so progress is likely slow.

The Buick La Crosse and Impala hybrids have a 20hp altermotor with a serpentine belt that passes the 20hp bi-directionally. The part is probably the same length with 1-1.5" larger diameter compared to the alternator you have now. The toothed belt has a massive turnbuckle to apply tension.

Beyond that a controller (HaroldinCR is using a Honda part) and a 72-120V battery pack.

Then you switch off when the light ahead turns red, wait it out, and then proceed across the intersection and fire up the engine at 20mph.

And you can use the battery pack for a block heater.