# What engine responds best to turbo.



## 180SX-X (Sep 21, 2003)

What engine do you guys think responds best to Forced induction, mainly turbos? It doesnt matter from what manufacturer, nissan, honda(devil), mazda, even BMW and Benz.
IMO, i think Rotary engines respond(key word) best to turbos, cause they gain like 100HP from only like 5 psi of boost.


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## 2drcam (Oct 7, 2003)

the rotary engine may respond better and gain more hp, but their tq sucks. the new rx-8 has 250 hp stock and only 130 ft lbs tq. now hp is nothing without tq. tq = how fast your car goes/what you feel.


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## chimmike (Oct 17, 2002)

unfortunately boosting rotaries comes with the high cost of reliability, lol.


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## Harris (Nov 11, 2002)

Just a comment on the hp/tp thing. 

Remember this, "People buy horsepower, but they drive torque". That should gets things into perspective.


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## TheVodKA (Sep 19, 2002)

Larger displacement corresponding with larger turbo would probably have the biggest hp gain, but not necessarily 1/4 mile (infact far from it.) Mercedes 600 gained around 150 hp by going to a twin turbo setup in 2k3


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## Murph (Aug 8, 2002)

The KA24DE responds very well to low boost.

Like vodKA said, big displacement usually responds the best.


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## 2drcam (Oct 7, 2003)

well look at the grand national. 3.8 turbo, big displacement. I think it's ~150hp and 250+ lb tq. that's a powerful stock car with alot of potential.


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## 180SX-X (Sep 21, 2003)

OooO, Grand Nationals here kick every1 ass(sep da only skyline that drags and 2 supras)


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## McLaren F1 2003 (Jan 2, 2003)

reading this thread made me wonder...how come dsm's need like 73464362526 lbs of boost?


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## sersr20dk (Oct 15, 2003)

because they can- because of the lower compression that the motors have, 1g's were 7.8:1, and also you want as much boost as the motor can safely handle anyway don't you? and also the comment about rotaries making no torque, that is only true with the na rotaries, boosted is a whole different story


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## Harris (Nov 11, 2002)

McLaren F1 2003 said:


> *reading this thread made me wonder...how come dsm's need like 73464362526 lbs of boost? *


C/R is probably a major reason why they can take more boost, but the lower C/R of the DSMs comes at a cost, which is that it will need more boost to run the same quarter mile time as say, an SR20DET. 

C/R also affects how much hp an engine makes at a particular amount of boost. Example: A turbo'd 9.5:1 SR20DE will make a little more hp than a 8.5:1 SR20DET at the same amount of boost. However, the lower C/R engine will be able to handle more boost, and therefore have lesser chances of detonation than a higher C/R engine.


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## 2drcam (Oct 7, 2003)

well, you can turbo a 9.5:1 C/R motor but only about 5-7 lbs auto and 7-9 lbs manual. anything more that that then you'll be blowing chunks of pistons out the exhaust.

basically you don't want to denotate. buy forged low C/R pistons. at least 8.5:1 if you plan on some serious boost. But with any motor (even rotary) you don't want to denotate. this means bye, bye motor.

i heard the rotary motor is 11:1 C/R. don't plan on boosting high w/ this motor, it will be a waste imo.


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## sersr20dk (Oct 15, 2003)

you can boost the crap out of rotaries, sr20 pistons can handle more boost than 7-9 lbs, i know a few people who run 12-15 on stock pistons with the right tuning and have no problems, and detonation while not good in any motor isn't as bad in a rotary because there are no rods or pistons moving up and down, so there is less chance detonation will be catostrophic


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## 2drcam (Oct 7, 2003)

sersr20dk said:


> *you can boost the crap out of rotaries, sr20 pistons can handle more boost than 7-9 lbs, i know a few people who run 12-15 on stock pistons with the right tuning and have no problems, and detonation while not good in any motor isn't as bad in a rotary because there are no rods or pistons moving up and down, so there is less chance detonation will be catostrophic *


they can still denotate...right?? hence, burning a hole, cracking somewhere...


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## McLaren F1 2003 (Jan 2, 2003)

i made the statement about the dsms because the evo has like 17lbs of boost stock or something

now give an sr20 17lbs...


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## sersr20dk (Oct 15, 2003)

yes they can still detonate and no it isn't good for the motor at all, the heat will cause cracking/holes as you have mentioned, evo's run between 16 and 19 lbs, rpm dependant, it is a good setup and proven, the c/r on a evo 8 is 8.8 to 1, which would make a good comparison to the gti-r motor, which would more than likely put down slightly larger numbers with such high boost , but you have to take into account the quad tb's of the gti-r and it seems to me that the two motors are pretty much equal in strength, although i like the feel the sr20 is a somewhat smoother motor


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## niky (Jul 20, 2002)

Unfortunately, as Nissan never produced the SR20*D*ET (not the VET, mind you)... boosted in the same range as the 4G63... and since they never made more than a half-hearted effort to get into rallying, we'll never be able to compare these two motors fairly, stock to stock at similar boosts...


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## sersr20dk (Oct 15, 2003)

that is true, that platform, stock vs. stock, would be the best way


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## Taffy (Oct 30, 2003)

2drcam said:


> well look at the grand national. 3.8 turbo, big displacement. I think it's ~150hp and 250+ lb tq. that's a powerful stock car with alot of potential.


The 87 GN came stock with 245 horsepower and 355 ft-lbf of torque. They respond very well to turbocharging because they put out a lot of exhaust and have small intake runners. That is good for torque, but bad for horsepower. A bigger turbo was the best mod I ever did to my GN.


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## sr20racer (Jun 29, 2002)

I think the SR20 does well, I went from 150whp to 220-230whp from 6.5 psi put out of a T25 :thumbup:


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## 180SX-X (Sep 21, 2003)

Taffy said:


> The 87 GN came stock with 245 horsepower and 355 ft-lbf of torque. They respond very well to turbocharging because they put out a lot of exhaust and have small intake runners. That is good for torque, but bad for horsepower. A bigger turbo was the best mod I ever did to my GN.


what is a GN?


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## sr20racer (Jun 29, 2002)

Grand National


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## 180SX-X (Sep 21, 2003)

oh


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## Nismo5042 (Nov 18, 2003)

*rx-7's*

rx-7's in there stock form can not handle that much boost. as soon as you crank up the boost on the stock motor you will be replacing apex seals really soon. but once you replace the apex seals with thicker ones they can hold nice boost. and also they don't really make to much power down low.


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## 180SX-X (Sep 21, 2003)

Nismo5042 said:


> rx-7's in there stock form can not handle that much boost. as soon as you crank up the boost on the stock motor you will be replacing apex seals really soon. but once you replace the apex seals with thicker ones they can hold nice boost. and also they don't really make to much power down low.


this is true, but they do respond well 2 boost. the n/a fc makes 135hp while the turbo made 200hp(in 92) on 6psi of boost wich is a 65hp gain on so little.


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