turbo vs supercharger

[turbovr41991]

Keep in mind what the original person who started threads original question.

Originally Posted by Wonderjava

which one is the best to get the most mpg and hp out of it?

It was not:
Should I do areo mods or turbo?

It was not:
It is cost effective to do add a turbo to improve MPG?

He asked a pretty simple question guys.

Most MPG and HP out of a turbo or supercharger. Of the two the turbo is the more efficient one. period.

[meanjoe75fan]

One thing to keep in mind: a turbo can be designed for performance, or for fuel economy. Although a turbo CAN up FE, sports-tuned turbo setups frequently do worse than NA engines of the same HP rating.

Most of it comes down to turbine sizing. Suppose you need more top-gear HP at freeway speeds: you shoild size the turbine such that full boost comes at.WOT and freeway RPM without opening the wastegate.

)The downside is that this would use a "huge" turbine that added little power down low, and was laggy as hell, due to the massive turbine inertia.

Typically, turbo engines modified for aviation use (steady-state power) will use a 7L turbine for somethi.g like a 2L subaru.

Cases in,point: my stepdad owned a mid-80s Saab 9000 turbo. It was known for high mpg-but was very laggy. The 2002 WRX I owned had lots of power, virtually no lag-and got 17 Mp

[Wonderjava]

ok all that being said...is it possible to swap say a 6 cylinder in for taking the underpowered 4 cylinder out? i asked a mechanic one time and he said yes the car is very underpowered for its weight, but because of the shape of the engine compartment (or some crap like that) a new engine would not be able to be put in....is that true? am i screwed in this deal and cant get a better engine? well i dont know what you mean by n/a engine, but my car is an 01 pt limited edition if that makes any difference to anyone...i want to either put on a turbo charger or put a stronger engine in the car...thoughts?

[Flakbadger]

Originally Posted by Wonderjava

i dont know what you mean by n/a engine

N/A is an abbreviation for "Naturally Aspirated," meaning no turbo or supercharger.



EDIT: More thoughts: Try looking up a PT-Cruiser forum and see what kind of engine swaps people are doing, that should give you an idea of what's in the realm of easy possibility.

[NoD~]

Originally Posted by Wonderjava

ok all that being said...is it possible to swap say a 6 cylinder in for taking the underpowered 4 cylinder out? i asked a mechanic one time and he said yes the car is very underpowered for its weight, but because of the shape of the engine compartment (or some crap like that) a new engine would not be able to be put in....is that true? am i screwed in this deal and cant get a better engine? well i dont know what you mean by n/a engine, but my car is an 01 pt limited edition if that makes any difference to anyone...i want to either put on a turbo charger or put a stronger engine in the car...thoughts?

If you are an auto tranny, it's not very easy to get good power gains. A manual has big advantages right off the bat.

Being a Neon guy, I can tell you that there are mods you can do to the current engine that are fairly cheap that would add a little pep to the car.

If power is your #1 requirement, look for a used SRT engine/tranny and swap it. It won't be cheap, but those engines can put some massive amounts of power to the ground. A local guy got the stock turbo and block to something like 350whp (with nitrous). I've also seen quite a few 400+whp builds on the stock block. But the stock engine alone would probably be a HUGE improvement. Those small Mitsubishi TD04 turbos spool fast enough to make it feel nearly N/A!

If you just want to go a cheaper route, the only performance part I would really recommend for the money is an Underdrive Pulley. I have yet to be impressed by the gains from one, especially when you compare to the price of an intake, exhaust, or header, in comparison to the actual amount of power they put down. Also, the UDP's seem to offer a bit better mileage and the power is across about all RPMs. Most bolt-on mods only seem to wake up the top end. If you want that top end power, I'm sure a cold air intake system, header, and exhaust system (probably just a muffler swap) would help.

2.4L engines also have a anti-resonance... thing. I can't remember, it's been a while since I've worked on one... Balancing shafts? It's in the oil pan. Many 2.4L users remove it. It adds vibration from the engine to the car, making it a little less comfortable, but adds a bit of power by keeping a bit of the parasitic drag down. It's basically a "free" mod, but you have to know what you are doing before going in there, hacking away.

Cams would be another option. Though, expect a noticeable drop in MPG when you start going that route. It can also add on the price, with a need of better springs swapped out on the head. Expect a lot of time put into this, or spending quite a bit to have a mechanic put them on for you.

If you really wanted to turbo your current engine, I'm pretty sure the stock SRT or Turbo PT cruiser turbo-fold will bolt right on to your head. Again, you'll need a lot of "nickle and dime" parts that add up very quickly, but you can probably boost 4-7psi on that engine without issues... assuming a proper tuning of course. Expect to use premium gasoline in all instances of having a turbo in your car.

Finally, weight reduction. The more weight your car has, the more power it takes to move it. If you can start pulling things you don't need out, you'll find it gets a bit peppier. Rotational mass is a HUGE one. Get rid of any big, fancy rims and go to the lightest and smallest wheels you can afford. I recommend the Rota Slipstreams... they are cheap and weigh very little. I swapped a friend one day, my 15" Rotas for his 17" "fancy" rims. The difference was definitely noticeable for both of us! My old race neon got down to 2250lbs with full interior... though it was loud, rattly, and vibrated your fillings out... it was able to run 14.2 in the 1/4 mile on it's 2.0L engine (cams and nearly every bolt on you could find). Just make sure that whatever you pull out isn't going to be needed.

Good luck!

[serialk11r]

Originally Posted by Old Tele man

TURBOCHARGER takes its "driving" power from the waste heat-energy of the exhaust, ie: basically "free" power.

SUPERCHARGER gets its "driving" power directly from the engine crankshaft, usually via an under-driven belt ratio, ie: it's a not "free" power but rather is a "load" on the engine at all times.

Except, a turbocharger is always creating a non-trivial amount of restriction in the exhaust, and on throttle plate controlled engines this always translates into pumping loss. Electronic wastegates can reduce this slightly though.

Furthermore, positive displacement superchargers are always equipped with bypass valves and twin screw type superchargers sometimes have electromagnetic clutches, so in most driving conditions the parasitic load is very small.

Thus, most people who add superchargers seem to report identical fuel economy, while people adding turbochargers usually see reduced fuel economy. Under full load though, a well designed turbocharger system is certainly more efficient.

[UltArc]

General rule, super gives power, turbo is efficient.

What everyone said is right. At least, to my knowledge. A nice thing about a good forum. One individual suggested a low rpm turbo, to counter the last comment. Realistically, that is the way to go.

[Neen]

Wonderjava...check out PTCrew. They are performance guys who know the PT inside and out. Truth is; if you have an auto 2.4L N/A PT you are only asking for serious issues if you turbo it. If you want more power and want a PT...sell yours and buy a PT GT. If you are hell bent on keeping your current PT...then an engine swap and transaxle swap are really your only options. A V6 would be hard to fit in a PT especially if you are inexperienced with swaps, fabrication, engineering in general.
NoD is spot on...reduce PT weight is really your only good option with your current drive-train setup. Remove the rear seats, get low weight rims/wheels.

[UFO]

Originally Posted by serialk11r

Except, a turbocharger is always creating a non-trivial amount of restriction in the exhaust, and on throttle plate controlled engines this always translates into pumping loss. Electronic wastegates can reduce this slightly though.

Furthermore, positive displacement superchargers are always equipped with bypass valves and twin screw type superchargers sometimes have electromagnetic clutches, so in most driving conditions the parasitic load is very small.

Thus, most people who add superchargers seem to report identical fuel economy, while people adding turbochargers usually see reduced fuel economy. Under full load though, a well designed turbocharger system is certainly more efficient.

Actually, if you remove the muffler like I did, the restriction is quite trivial under light loads, and parasitic loss is far lower under boost than that supercharger. I wouldn't rely on fuel mileage reports from power junkies; that said I get 29-30 mpg on a factory turbo engine swap in my 280Z, despite the low compression ratio (7.4:1), and that was better than the original n/a engine in the car. Best I ever got on the original engine was 25mpg, same speeds, same trips.

I'd be willing to bet turbos are more efficient than a clutched supercharger system across all operating conditions. But I've not seen data if there is any.

[vrmilionzx]

Originally Posted by NoD~

Finally, weight reduction. The more weight your car has, the more power it takes to move it. If you can start pulling things you don't need out, you'll find it gets a bit peppier. Rotational mass is a HUGE one. Get rid of any big, fancy rims and go to the lightest and smallest wheels you can afford. I recommend the Rota Slipstreams... they are cheap and weigh very little. I swapped a friend one day, my 15" Rotas for his 17" "fancy" rims. The difference was definitely noticeable for both of us! My old race neon got down to 2250lbs with full interior... though it was loud, rattly, and vibrated your fillings out... it was able to run 14.2 in the 1/4 mile on it's 2.0L engine (cams and nearly every bolt on you could find). Just make sure that whatever you pull out isn't going to be needed.

Good luck!

Yea!