How fast is 400hp?

[G35turbo]

Well I drive a 97 vr4 and my car is stock beside i just ordered my ACT Heavy Duty clutch. I was lookin to get about 400hp on my car and i was wondering if anybody has done or knows what is the 1/4 on the vr4 with 400hp on the belt (NOT AT THE WHEEL).

If you dont know the 1/4, what cars have u guys raced that was faster than the stock vr4 but after 400hp your beat it?

And also how much hp do you get from intake, catback, downpipe, high flow cat, boost up to 14psi. Do u guys think 400hp or more or less?

Thank You

[Igovert500]

With intake, downpipe, boost controller at 14.5psi, gutted precats you should be 375-400hp. Add the catback you mentioned and that'll put you pretty close if not over. Not to mention the clutch will help in the launch.

Estimated 1/4 for those mods is around 12.8

[G35turbo]

Well i read the 3si thing about modin your car and it said that you shouldent go over 14psi with stock injectors, dose .5 psi change a lot if so how much and dose 14.5 hurt your car or is it just not whole lot of difference?

[Igovert500]

Generally rule of thumb is 14-15. 14 is conservative, 15 is borderline dangerous, as you can get knock if the weather changes...14.5 is the highest I'll go without upgrading the fuel system and datalogging. Your engine...your choice, but I don't recommend 15.

[aorozco2]

if you want to figure out the 1/4 for any car go to http://www.fantasycars.com/derek/quartmile.html

[Igovert500]

that thing is next to worthless...it only factors in weight and peak hp...not torque, traction, aerodynamics, gearing, etc.

[YogsVR4]

Originally Posted by Igovert500

that thing is next to worthless...it only factors in weight and peak hp...not torque, traction, aerodynamics, gearing, etc.

Its not worth a damn.

[ikOnone]

i agree, that site is worthless but...

it was fun to see an estimate of how fast a 1000 hp 1 lb car would run a 1/4 lol. apparently i twould go in about .6 seconds. they must have some REALLY sticky tires

another thing that it does not take into account that was alluded to but not mentioned is the hp and tq curves. if they can only make that for 500 rpm before they redline and they are not making hardly any before that they would not be as fast as someone with a smoother curve but less peak hp and tq.

[Linebckr49]

a few things i think we're all overlooking here...

as far as 400hp goes, i think you'll need a bit more than just a boost contorller set at 14.x psi, intake, downpipe, gutted precats, cat-back, high-flow cat. The thing is that the 320hp that is quoted/claimed for the VR4 is HP AT THE CRANK. and so, with the AWD, your only pushing about 240 or 280 AWHP ( i forget which figure is the one). And so you would have to go back to your original quest for 400hp--> do you want to FEEL 400hp, or just have your engine put out 400hp?? Lets not get too hopeful and forget the realism of drivetrain loss.

and the 14.x psi max setting: i think the actual number is 1 atmosphere OR 760mm of mercury (Hg) OR 14.7psi (all equivalent values, in different units of course, of atmospheric pressure). I can't remember why that is the maximum safe boost setting for the stock 9b turbos, but i know that the stock turbos aren't that efficient/effective b/c they won't hold 14.7psi ot redline. also, beyond a certain boost (maybe 14.7psi) the turbos are inefficient b/c they're just blowing hot air into the engine. And i THINK that is caused by the limit of our stock sidemount intercoolers to cool the incoming air. not sure, someone let me know if i'm wrong about the intercooler-result.

[ikOnone]

do you want to FEEL 400hp, or just have your engine put out 400hp??

from the first post

Originally Posted by G35turbo

I was lookin to get about 400hp on my car and i was wondering if anybody has done or knows what is the 1/4 on the vr4 with 400hp on the belt (NOT AT THE WHEEL).

and those mods should get about 400 hp at the crank with a well running car. another rule of thumb is 10 hp per 1 psi added so this can help to estimate what a boost controller but as with many such rules of thumb, it is not accurate in all situations (elevation, nonlinearity, point of deminishing returns due to lost efficiency, etc.)

also, whether or not you "feel" 400 hp is subjective. i would call feeling 400 crank hp feeling 400 hp. it is not at the wheels but then again we get to "feel" a more intense launch. new C6 vetts are 400 hp but i am almost sure that they are quoting crank hp and they probably still have 15% drivetrain loss or something like that. i bet they would still call that feeling 400 hp not 340 hp. on the other hand, once you start modding, wheel hp is generally what people measure because it is easier and more accessable so that is what modded cars often quote. it is all subjective though.

i think the actual number is 1 atmosphere OR 760mm of mercury (Hg) OR 14.7psi (all equivalent values, in different units of course, of atmospheric pressure).

14.5 psi is a rule of thumb and has nothing to do with atmospheric pressure at sealevel. many people claim that it is acctually perfectly safe to run more than 15 psi on stock everything but 14.5 is a general rule of thumb that is safe.

I can't remember why that is the maximum safe boost setting for the stock 9b turbos

the reason for this boost level suggestion, as i said before, has nothing to do with atmospheric pressure but is mainly due to the limitations of fuel flow due to the stock injectors and fuel pump. after upgrading those, you can run more boost on the stock turbos.

but i know that the stock turbos aren't that efficient/effective b/c they won't hold 14.7psi ot redline. also, beyond a certain boost (maybe 14.7psi) the turbos are inefficient b/c they're just blowing hot air into the engine. And i THINK that is caused by the limit of our stock sidemount intercoolers to cool the incoming air. not sure, someone let me know if i'm wrong about the intercooler-result.

correct in some ways and off in a few i believe. the stock turbos will not hold 14.7psi to redline, they will only hold about 9 or 10 psi to redline. however, i believe that the turbos should be in decent efficiency range for much of the rpm range until about 17 psi but as we said, they will not flow enough to hold that to redline. stock intercoolers are not that great but they do a decent job unless you are going a decent amount higher than bpu. heck, some of the fastest 3/S runs ever were done on the stock intercoolers, not that that makes them good though.

so, with the AWD, your only pushing about 240 or 280 AWHP ( i forget which figure is the one).

300 - .25*300 = 225 AWHP (1st gen)
320 - .25*320 = 240 AWHP (2nd gen)

this is agan a rule of thumb (25% drive train loss) but this is generally about what stock cars put down. i personally like to remind people to think of how drivetrain loss acctually happens and remind them that nothing in life is linear so you can't allways say 25% (aka, if you have a 1000 hp 3/S you are not going to lose 250 hp in the drive line, as if it could take 1000 hp anyway ) but it is probably closer to 80 hp no matter what and then slightly more as hp increases.

[G35turbo]

So how much is my HP going to add up if i get:
K&N Intake: (hp)
HKS Cat-Back: (hp)
Blitz SBC Spec-R Boost Controller: (hp) 14psi
3" Stainless Steel Downpipe: (hp)
3SX TT 3.0" Race Pipe: (hp)
TOTAL )

Linebckr49, what do u mean by drivetrain loss?

[ikOnone]

oh, also, efficiency drop off is due to the turbos but the stock intercoolers can have problems counteracting the efficiency loss if they are too far out of their efficiency range. for more turbo efficiency info, check out www.stealth316.com then go to garage and then go to compressor flow maps (near the top left of the list)

[talskinyguy]

he said he was looking for CRANK hp not whp.

[ikOnone]

Originally Posted by G35turbo

So how much is my HP going to add up if i get:
K&N Intake: (hp)
HKS Cat-Back: (hp)
Blitz SBC Spec-R Boost Controller: (hp) 14psi
3" Stainless Steel Downpipe: (hp)
3SX TT 3.0" Race Pipe: (hp)
TOTAL )

Linebckr49, what do u mean by drivetrain loss?

about 400 crank hp and about 310 AWHP assuming your car is otherwise running well. drivetrain loss is the energy that is lost after the crank (or flywheel depending on who you talk to). there is heat and friction and rotating inertia and all sorts of places for energy to be lost. no car has the same amount of hp at the crank as they do at the wheels but with better drivetrains, lighter parts, and fewer wheels to spin, drivetrain loss goes down.

[Igovert500]

Originally Posted by G35turbo

Linebckr49, what do u mean by drivetrain loss?

The difference between hp at the crank and hp that gets to the wheels...hp is lost between the engine and wheels as it must turn the flywheel, driveshaft, wheels, etc...all of these parts absorb hp in getting htem rotating.