NA or Turbo?

[Geneticdrift]

Just wanting to know what people of this forum prefer........please tell why you like the one you choose any special reasons??

 

[NoQuarter]

I actually did a test a while back with the RGT. I bought two, and set one up as a turbo and the other as NA...power was fairly balanced (in the 600 HP area, IIRC) and all other fitments were identical...full suspension, brake/controller, racing tranny/LSD and lightweight mods and T8 tires.

All settings were identical.

I initially started testing the two at Complex String, and was surprised to find them fairly closely matched...as I recall, the NA version was slightly faster, as it seemed to come out of the hole stronger on exiting the tight turns, while the Turbo seemd to peak the top end on the longer stretches...overall, it was close to a wash, with the NA taking a very slght nod (less then 1 second).

But when I took it to some hillier tracks (Deep Forest and Laguna Seca), the NA was definitely the stronger. No doubt, the broader power band was responsible for pulling the NA up the hills with more authority.

At wide open tracks, such as GVS and Tokyo, the Turbo version was slightly favored, being able to hit the top end stronger on the long straights.

Sorry I don't have exact figures, this was about 6 months ago...

Short answer? Depends on where you run, at least in my book.

 

[Victor Vance]

This has already been discussed.

 

[Geneticdrift]

This has already been discussed.

Sorry Please close this thred....

 

[pergatory]

I think a topic like this is ok to revisit since it's an "opinion" topic not a "learn the answer" topic. Personally, I prefer turbo, and I don't know that I could really say why. I had the pleasure of owning a turbo'd car and once I learned how to take advantage of it, I swore I'd never go back. (Alas, I'm driving an AE86 now and loving it, but I'm on the market for an S13 or S14.) I think the reasoning lies in what's called usable torque. Due to the reciprocating (jerky) nature of the engine, the power that the engine applies to the wheels is also very jerky. However, a charge that is under higher pressure will burn more evenly throughout the stroke of the engine. What this means is that higher boost = more even distribution of power throughout each revolution. This allows you to make more use of the traction you have. You can literally put more power down on a forced induction engine. In drifting, this becomes even more apparent. Likewise, it is also more apparent on race-modded engines with lightweight flywheels and such. Ever hear a turbo engine and NA engine revving together? The turbo engine sounds smoother, more like a constant tone, but the NA has more defined firing patterns.

P.S. - Rotary engines also have higher usable torque.

P.P.S. - This probably has no effect whatsoever in GT3.

 

[Victor Vance]

Lucky hachi roku mf I'm gonna find u and steal ur ride

j/k still sweet wheels, my Dad once had a '79 Capri RS Turbo and '84 or '85 Mustang SVO, he said it was about the sportiest thing he's driven, which isn't saying much
(dad's list of driven/owned cars is a long, long list of good old fashioned American iron, including Dodge Darts, C2 Corvettes, Plymouth RoadRunners and the like)

 

[kikkoman]

Don't quote me on this, but I think Geneticdrift was reffering to which car would you rather use to drift with in Gran Turismo 3.

 

[Victor Vance]

Right, back on topic, NA, because Stage 3 gives you more revs

 

[ForcedInduction]

NA, because Stage 3 gives you more revs

wow never knew that. You mean as in it increases your redline?

 

[ToyotaDrifter]

cool... but does this apply to gt3?

 

[Ottoman]

I think a topic like this is ok to revisit since it's an "opinion" topic not a "learn the answer" topic. Personally, I prefer turbo, and I don't know that I could really say why. I had the pleasure of owning a turbo'd car and once I learned how to take advantage of it, I swore I'd never go back. (Alas, I'm driving an AE86 now and loving it, but I'm on the market for an S13 or S14.) I think the reasoning lies in what's called usable torque. Due to the reciprocating (jerky) nature of the engine, the power that the engine applies to the wheels is also very jerky. However, a charge that is under higher pressure will burn more evenly throughout the stroke of the engine. What this means is that higher boost = more even distribution of power throughout each revolution. This allows you to make more use of the traction you have. You can literally put more power down on a forced induction engine. In drifting, this becomes even more apparent. Likewise, it is also more apparent on race-modded engines with lightweight flywheels and such. Ever hear a turbo engine and NA engine revving together? The turbo engine sounds smoother, more like a constant tone, but the NA has more defined firing patterns.

P.S. - Rotary engines also have higher usable torque.

P.P.S. - This probably has no effect whatsoever in GT3.

I own 2 turbo cars (see sig) as well and have driven some very mean N/A powered cars (E46 m3)

the powerband of a Turbo car is always smaller then that of an N/A car... because the pistons are lower compression there is no power until the snail opens... at the same time this makes the car feel fast then it really is... because there's nothing for the first 3,500 revs then BOOM u get punched with full boost...

so that's why Turbo engines are very "peaky" in performance...(why do u think ppl complain so much about turbo lag? cuz there's no power when the snail aint spinning)

u were talking about high pressuer of air in the cylinder chamber helping performance... if u use High compression pistons u'll yeild the same Result... weather u compress it then cram it into the combustion chamber, or u compress the air inside the chamber on the up stroke...

N/A high compression engines.. like the M3 for example.. throttle response is much superior.. there's instant power when u want it... with a turbo car u hafta "wait for it" (turbo lag)

so this makes the Powerband much wider and more usable on a N/A car rather then a Turbo car which requires much better working of the gears... (but in GT3 we all use racing trannys with insanely close gear ratio's so u don't notice it as much... plus it's only a game )


as for u're statement on rotaries... they have NOO low end torque what so ever.. infact u hafta rev the piss outta them to make any power... the major point of success of the rotary i the compact nature of the engine... making the car very well balanced thus good handling...and it's innovative design... and free revving characteristics.. not it's Torque


the reason Turbo cars are popular.. is cuz it's Easier and Cheaper and better bang for buck to make it faster... N/A cars cost alot more and u get less gains...
but if money is not an Object.. then High Compression N/A makes a superior race engine then Turbo

 

[pergatory]

Sorry to get so far off topic here since I'm fairly sure we're way beyond what GT3 takes into account but...

I own 2 turbo cars (see sig) as well and have driven some very mean N/A powered cars (E46 m3)

I hate you! Those are some very nice cars.

the powerband of a Turbo car is always smaller then that of an N/A car... because the pistons are lower compression there is no power until the snail opens... at the same time this makes the car feel fast then it really is... because there's nothing for the first 3,500 revs then BOOM u get punched with full boost...

so that's why Turbo engines are very "peaky" in performance...(why do u think ppl complain so much about turbo lag? cuz there's no power when the snail aint spinning)

Turbo lag can be minimized if the turbo installer knows the slightest bit about turbos. We're not talking about drag racing with 40 PSI here, a good 15 PSI boost is more than enough. On a decent-sized (say 2.0) engine it's easy to get such boost from say 2500RPM to redline. In fact, turbocharged engines actually have much flatter torque curves than NA, NA is the peaky engine due to the fact that it depends on high revolutions to move more air. Turbo doesn't need high engine RPM it only needs high turbo RPM to move air. There may be less power before the turbo spools but that can be minimized by a good driver who knows how to take advantage of turbo power.

u were talking about high pressuer of air in the cylinder chamber helping performance... if u use High compression pistons u'll yeild the same Result... weather u compress it then cram it into the combustion chamber, or u compress the air inside the chamber on the up stroke...

N/A high compression engines.. like the M3 for example.. throttle response is much superior.. there's instant power when u want it... with a turbo car u hafta "wait for it" (turbo lag)

Let's take an example. Let's look at the '01 BMW M3 which runs at 11.5:1 compression. Let's say you modify it to run 12:1 compression which we can all agree is fairly high. At sea level, assuming 100% volumetric efficiency, the pressure in the combustion chamber at TDC will be 174 PSI (absolute, not gauge).

Now let's take the example of an engine running 9:1 compression (about average for a turbocharged engine) and a mere 10 PSI of boost. Unboosted, this would create 130.5 PSI. Add the boost, and the result is 220.5 PSI (also absolute).

In fact, in order to get the same compression in the M3 you would have to be running 15.2:1 compression, and that's only up against 10 PSI of boost! Enough said?

NA engines do normally have the advantage in the throttle response category, but personally I never thought throttle response was very important. As long as the driver is good, he/she can predict when power will be needed and begin spooling the turbo before-hand. In racing, if you're "waiting" for something then you've already lost. Throttle response is a luxury. ^^

as for u're statement on rotaries... they have NOO low end torque what so ever.. infact u hafta rev the piss outta them to make any power... the major point of success of the rotary i the compact nature of the engine... making the car very well balanced thus good handling...and it's innovative design... and free revving characteristics.. not it's Torque

Torque, and usable torque, are two completely separate things. You're right, rotaries don't have much in the way of torque. However, the torque they do produce is more "pure" so-to-speak. More torque can be applied to the same tires without peeling out if it is a rotary engine generating the power. That's all I was saying. It's the same with turbos, a turbo engine can apply more power to the same tires without losing traction.

 

[Ryen49]

This is the type of Conversation we need in the drifting forum.

 

[Thio]

Ah yes, finally!

This is more automotive technology rather than drifting, but it is a good thread to read once in a while

Do not mind me, I am just fascinated at how much more I have to learn about cars.

 

[Ottoman]

Sorry to get so far off topic here since I'm fairly sure we're way beyond what GT3 takes into account but...

Turbo lag can be minimized if the turbo installer knows the slightest bit about turbos. We're not talking about drag racing with 40 PSI here, a good 15 PSI boost is more than enough. On a decent-sized (say 2.0) engine it's easy to get such boost from say 2500RPM to redline. In fact, turbocharged engines actually have much flatter torque curves than NA, NA is the peaky engine due to the fact that it depends on high revolutions to move more air. Turbo doesn't need high engine RPM it only needs high turbo RPM to move air. There may be less power before the turbo spools but that can be minimized by a good driver who knows how to take advantage of turbo power.

hmm.. which Turbo engine do u talk of spooling 15 psi@2500rpm?

My SR20 pushing a small T-25 spools up at 3- 3,500...
the 4G63 pushing the big 16G spools up even later

both are 2 liters...

in order to get "hugh turbo RPM" to move the turbo's fins.. u need the heat energy and exhaust gases from the engine to push that turbo.. Higher revs=higher heat energy=spooling...

U can miminize turbo lag by...
a) putting a Small turbo
b) bang bang/miss firing system (good luck on a street exhaust)
c) exhaust wrapping the headers
d)power shifting on upshifts and Toe+heeling downshifts
e)i mighta missed a few small ones
[/quote]

Let's take an example. Let's look at the '01 BMW M3 which runs at 11.5:1 compression. Let's say you modify it to run 12:1 compression which we can all agree is fairly high. At sea level, assuming 100% volumetric efficiency, the pressure in the combustion chamber at TDC will be 174 PSI (absolute, not gauge).

Now let's take the example of an engine running 9:1 compression (about average for a turbocharged engine) and a mere 10 PSI of boost. Unboosted, this would create 130.5 PSI. Add the boost, and the result is 220.5 PSI (also absolute).

SR20DET.. arguably one of the best 4cyl Turbo engines.. has a compression ratio of 8.5 and runs 7psi Stock

and to run 100% VE.. u wont be using teh vehicle Stock... that means u got a 3" huge grenade launcher exhaust.. straight pipe no cats.. u got 2.25-2.5" intercooler Piping with a Low Restriction FMIC... as well as a decent induction kit...

what's the formula u're Using btw?
[/quote]

NA engines do normally have the advantage in the throttle response category, but personally I never thought throttle response was very important. As long as the driver is good, he/she can predict when power will be needed and begin spooling the turbo before-hand. In racing, if you're "waiting" for something then you've already lost. Throttle response is a luxury. ^^

it all depends on the the type of track.. if u're doin 1/4 mile or any straight line.. with WOT the whole way... throttle response means little... in drifting because u wanna be breaking traction alot of the time u've got the foot down alot

but in Auto X or other type of Twistie Grip driving... Power band and throttle response are very important.. and i think N/A really shines here where there's alot of braking hard accelerating hard etc...

Torque, and usable torque, are two completely separate things. You're right, rotaries don't have much in the way of torque. However, the torque they do produce is more "pure" so-to-speak. More torque can be applied to the same tires without peeling out if it is a rotary engine generating the power. That's all I was saying. It's the same with turbos, a turbo engine can apply more power to the same tires without losing traction.

i'm not sure i follow u here... u're sayin a rotary that produces 200 ftlb of torque will be able to put it through the wheels better then a piston engine making 200 ftlb of TQ? or just the fact that it doesn't make much TQ at all means it can't break traction??

 

[Ottoman]

Ah yes, finally!

This is more automotive technology rather than drifting, but it is a good thread to read once in a while

Do not mind me, I am just fascinated at how much more I have to learn about cars.

haha..

i guess u don't follow the "cars in general" forum

there was a HUGE thread on Engines.. after i discovered it.. ohh boy there was a biiig heated debated about American V8's vs imports... (i was supporting the imports obviously )

 

[Victor Vance]

wow never knew that. You mean as in it increases your redline?

No, but the rev limiter takes 500 more PRM to kick in... So your Lotus Espirit which normally hits the limiter at 7,500 rpm will hit the limiter 8,000 rpm with, say, the Trueno Stage 3 NA kit.

 

[ForcedInduction]

No, but the rev limiter takes 500 more PRM to kick in... So your Lotus Espirit which normally hits the limiter at 7,500 rpm will hit the limiter 8,000 rpm with, say, the Trueno Stage 3 NA kit.

okay i understand what you're saying. 💡

 

[Thio]

haha..

i guess u don't follow the "cars in general" forum

there was a HUGE thread on Engines.. after i discovered it.. ohh boy there was a biiig heated debated about American V8's vs imports... (i was supporting the imports obviously )

I do, so I am not out of the loop, lol, but threads in depth like this one do not appear a lot in that forum either

 

[Ottoman]

I do, so I am not out of the loop, lol, but threads in depth like this one do not appear a lot in that forum either

haha..

ya man.. it's nice to get technical once in awhile.. having a nice intellectual debate without turning into a flame war or "my member is bigger then your member" arguement..

based on facts and figures with some opinion and knowledge...

and gives a chance for other members to learn as well...

i know a thing or 2 about cars and engines... but there's always new stuff to learn everyday.. one of teh best ways is this way 👍

 

[pergatory]

hmm.. which Turbo engine do u talk of spooling 15 psi@2500rpm?

Saab 2.3L engine is the one I have direct experience with, using T3 with 45-trim compressor running 11 PSI it reached peak torque 243 lb-ft @ 1995 RPM. That was the factory spec, no modding involved. I cranked the turbo up to 22 PSI and it was fully spooled before 2500 RPM.

SR20DET.. arguably one of the best 4cyl Turbo engines.. has a compression ratio of 8.5 and runs 7psi Stock

and to run 100% VE.. u wont be using teh vehicle Stock... that means u got a 3" huge grenade launcher exhaust.. straight pipe no cats.. u got 2.25-2.5" intercooler Piping with a Low Restriction FMIC... as well as a decent induction kit...

what's the formula u're Using btw?

Must agree about the SR20, it's going to be my next engine. Anyway, 100% VE is not physically possible. I just stated that so that people couldn't start debating the symantics about VE. In the example, assume both engines have VE of 100% to make calculations easier, even though it's impossible. I don't know that I'm really using a formula, but my reasoning is like this:

At sea level, atmospheric pressure is 14.7 PSI. So I use the number 14.5 since majority of races take place above sea level. It's a nice round number. So an NA engine with compression ratio of 12:1 would have a combustion chamber pressure of 14.5 x 12 = 174.

For the turbocharged engine, the compression ratio is only 9:1 but the pressure is boosted above atmospheric to 24.5 (14.5 + 10). So the combustion chamber pressure is 24.5 x 9 = 220.5.

i'm not sure i follow u here... u're sayin a rotary that produces 200 ftlb of torque will be able to put it through the wheels better then a piston engine making 200 ftlb of TQ? or just the fact that it doesn't make much TQ at all means it can't break traction??

I'm saying the former. If you take two identical cars, one with a rotary and one with reciprocating piston engine, with each engine having exactly the same torque curve, redline, etc. So everything is the same except that one is rotary. In a perfect drag launch the rotary will win. It can apply more power to the wheels without breaking traction because the power is not applied in a jerky pattern. The difference is minute, yes, but not as minute as you'd think.

Of course, it really is minute if you don't have the power to break traction in the first place. But if you do, and have to hold yourself back in order not to break loose, a rotary will allow you to apply more power before you do.

 

[ForcedInduction]

pergatory, are you saying that the Saab 2.3 litre turbo engine kicks in at just under 2000 rpms?

 

[Ottoman]

Saab 2.3L engine is the one I have direct experience with, using T3 with 45-trim compressor running 11 PSI it reached peak torque 243 lb-ft @ 1995 RPM. That was the factory spec, no modding involved. I cranked the turbo up to 22 PSI and it was fully spooled before 2500 RPM.

interesting... what is 4 cyl or 6cyl? if it's 6 that might help explain it... and 2.3 liters is pretty hefty to be spooling a small turbo like that... 22psi?? was that even in the compressor map range? sounds like u're killin the turbo or just churning hot air at the level

Must agree about the SR20, it's going to be my next engine. Anyway, 100% VE is not physically possible. I just stated that so that people couldn't start debating the symantics about VE. In the example, assume both engines have VE of 100% to make calculations easier, even though it's impossible. I don't know that I'm really using a formula, but my reasoning is like this:

At sea level, atmospheric pressure is 14.7 PSI. So I use the number 14.5 since majority of races take place above sea level. It's a nice round number. So an NA engine with compression ratio of 12:1 would have a combustion chamber pressure of 14.5 x 12 = 174.

For the turbocharged engine, the compression ratio is only 9:1 but the pressure is boosted above atmospheric to 24.5 (14.5 + 10). So the combustion chamber pressure is 24.5 x 9 = 220.5.

tho on paper your math sounds ok .. but no offense but i don't think that'll really work... cuz the the temperatue of the compressed air is much higher then the N/A intake air.. so air density is lower on the turbo car..unless u have Very good cooling... that was another point I forgot to make:
turbo cars are much more dependent on Ambient temperatures then N/A... my cars feel HUGELY different on a cool night vs a warm day... i even installed water injectors to spray to intercooler.. it helps a little but still... i find the N/A engine doesn't get bothered nearly as much by it...

I'm saying the former. If you take two identical cars, one with a rotary and one with reciprocating piston engine, with each engine having exactly the same torque curve, redline, etc. So everything is the same except that one is rotary. In a perfect drag launch the rotary will win. It can apply more power to the wheels without breaking traction because the power is not applied in a jerky pattern. The difference is minute, yes, but not as minute as you'd think.

Of course, it really is minute if you don't have the power to break traction in the first place. But if you do, and have to hold yourself back in order not to break loose, a rotary will allow you to apply more power before you do.

interesting... i've never really looked into the TQ of a Rotary because i never considered it's TQ output as one of it's shining points... but never thought of it's TQ production.. learn something new everyday... even tho it produces that TQ well it's a shame it can't produce ALOT of it too...

 

[pergatory]

interesting... what is 4 cyl or 6cyl? if it's 6 that might help explain it... and 2.3 liters is pretty hefty to be spooling a small turbo like that... 22psi?? was that even in the compressor map range? sounds like u're killin the turbo or just churning hot air at the level

It was a 4-cyl. You're right it was a lot to ask of a wet turbo but it did fine. It's below the surge/redline on the map the whole time but you could tell it was getting hot after high-speed runs. The engine's redline was only 6500RPM. It was all stock internals.

tho on paper your math sounds ok .. but no offense but i don't think that'll really work... cuz the the temperatue of the compressed air is much higher then the N/A intake air.. so air density is lower on the turbo car..unless u have Very good cooling... that was another point I forgot to make:
turbo cars are much more dependent on Ambient temperatures then N/A... my cars feel HUGELY different on a cool night vs a warm day... i even installed water injectors to spray to intercooler.. it helps a little but still... i find the N/A engine doesn't get bothered nearly as much by it...

This is another thing I didn't take into account. However at only 10 PSI it wouldn't be difficult to keep the temps very close to NA. It is a big drawback of turbocharging though.

interesting... i've never really looked into the TQ of a Rotary because i never considered it's TQ output as one of it's shining points... but never thought of it's TQ production.. learn something new everyday... even tho it produces that TQ well it's a shame it can't produce ALOT of it too...

I'm waiting to see what they do with Renesis. Once they're confident enough to slap a turbo on a factory Renesis, I will certainly consider it as an option. However, you're right that the 13b just doesn't have enough torque to do the job, and the 20b and higher well... let's just face it, that's absurd.

 

[Ottoman]

It was a 4-cyl. You're right it was a lot to ask of a wet turbo but it did fine. It's below the surge/redline on the map the whole time but you could tell it was getting hot after high-speed runs. The engine's redline was only 6500RPM. It was all stock internals.

not bad.. looks like history of makin Jet fighters helps huh?

but considering it's a saab... how did u avoid Fuel Cut unless it's an older model with no fuel cut? were u detonating? i'm sure u musta been way past the max injector cycle duty considering u more then doubling stock boost... u musta way leaned out....

This is another thing I didn't take into account. However at only 10 PSI it wouldn't be difficult to keep the temps very close to NA. It is a big drawback of turbocharging though.

all depends on the car really... my SR's stock side mount intercooler was woefully inadequate... just by changing it to a front mount and opening up the exhaust the boost went up almost 3 psi! talk about restriction...eclipse is the same thing...
now GTR's and Supras have nice big Front mounts.. so i'm sure it effects them less...

I'm waiting to see what they do with Renesis. Once they're confident enough to slap a turbo on a factory Renesis, I will certainly consider it as an option. However, you're right that the 13b just doesn't have enough torque to do the job, and the 20b and higher well... let's just face it, that's absurd.

yes indeed.. i'd like to see how Trouble free these new engines are.. the old ones were a nightmare to maintain... hopefully these ones will as reliable as regular piston engines... and then... 9,500 redline plus Turbo.... mmmmmmmmmmmmmmmmmmmmmm *droooool* 👍

 

[divine_monk]

i know a thing or 2 about cars and engines

haha. your replies don't seem like 1 or 2 things. sorry to interrupt. please continue. this is getting interesting.

BTW. i prefer turbo for drifting. don't know why. i guess it just sounds cool to have a "turbo". people click when they hear turbo, but not many people even know what na stands for. haha.

 

[ForcedInduction]

BTW. i prefer turbo for drifting. don't know why. i guess it just sounds cool to have a "turbo". people click when they hear turbo, but not many people even know what na stands for. haha.

good point. But that is only in games. People tend to buy turbo because it produces more HP in the "GAME". In real-life turbo may not sound as BAD as it did in gran turismo. Both have their advantages and disadvantages.

 

[725]

I've certainly enjoyed the read 👍

 

[Geneticdrift]

Thanks guys for all your opinions and information it helped me alot!

 

[Ottoman]

no problem.. thats what we're here for.. to learn from one another... we all have our strengths and weaknesses it's good for us to exchange our strengths to help others weaknesses and vice versa so we all come out beneficial in the end 👍