How Much whp to 10s in a FD?
 

I calculate that you need aprox 470whp to run 10.9 on a fully built FD with drag radials (not slicks), cutting 1.6s.

THe problem is i know a few FDs with over 500whp, cuttin 1.6 and are only hittin 11.5-11.6. What could be the problem? Could it be the turbo hotside too big? None of these FDs are using nitrous nor have trans-brake.

I guess that a 1.06 turbo hotside takes longer to build boost and consequently longet 1/4 times

There was one in PR about 4 years ago with stock turbos (albeit they were being boosted to the point they only lasted like 8-10 pases at a time) using external wastegates instead of the internal ones and it had about 380whp and it ran a few 10.9's....it had slicks....absolutely no slip...the MPH were not that impressive, it was all grip...the guy wanted to prove a point with the stock turbos and he did.

So it can be done with less than 400whp....I am not sure if the interior was stripped....I would assume so.

Chris

I went 10.74's with 440 whp.

http://videos.streetfire.net/video/H...NOUT_54976.htm

wOW!! that was probalby with full slicks.... I am asking for 10s with a full interior car and drag radials.

My concern is, besides whp, does the turbo hotside affects times? which setup is better :

440whp with a 0.81 hotside,
440whp with a 1.06 hotside

Does the turbo spool affects the times, if i am not using a trans-brake system?

I would think that it does. Times are affected by the area under the hp curve. If you have two cars that both have 440whp but with different spool characteristics...and with the same gearing, tires etc....the one with the "beffiest" hp curve would have a faster mph/e.t. assuming they both grip the same.

a smaller housing yields a better powerband to a certain extent...of course if you are shifting at 8krpm and that makes you fall to 6krpm between shifts then a turbo that is smaller and give you power from 3k rpm is sorta being wasted so you might as well go with a larger housing that gives good power from 5k on but has a nicer flatter top end where you will be using it.

It all has to do with how you are driving the car and the conditions.

Chris

Use the stock twins as example, several guys went 11.1-11.3 at 117-119mph. Most of those guys then switched to singles and went only a slighty faster E.T. around 10.7-10.9 but at near 10mph faster.

^^ Never thought about that.

my concern is because, 3 fds i know with over 500whp, big turbos, cuttin 1.6 times, didn't manage better than 11.6-11.5. I have 429whp and i feel that i could do 11.6 also with less whp and a smaller turbo.

So powerband helps.

Power band helps yes, but if you arent in the 10's with 500whp, you need to learn how to drive.

Nope, just ET Streets...

Agreed,
also a pair of balls when you dump the clutch @ 7k and keep it together all the way to the big end helps

i've run 10.9x with 465 rwhp.

I think the 500+ whp Fds running 11.5s have traction or driver issues. With 410 rwhp I ran 11.5 @ 124.32 on a street car with drag radials with 2.0 60' times.

If what your saying is true then a 1.5 or 1.6 60' in your case would get you into mid to high 10's with 410rwhp. Didnt JD or boostn7 run 10.90 with stock twins and about 420hp ?

So there is the answer to how much HP is needed but remember HP alone wont make your car run 10's.

he sure did! i don't remeber his exact dyno numbers but if i recall they were around 420-430whp.

Yes I remember when he ran 10s on modded stock twins and in the low 400 hp. That was awesome. Didn't he run like a million low and flat 11s too?

410 hp dyno run:

http://videos.streetfire.net/video/s...-fro_59487.htm

11.5 run:

http://videos.streetfire.net/video/O...asts_87738.htm

A good old friend of mine that is VERY knowledgeable about this stuff has always said that you only need 340 rwhp to run 11s in an FD. But there are all kinds of different driving styles out there...