SH Luciano

iTrader: (1)

i agree it has a lot to do with suspension. look at the zr1 - 638hp from the factory and it's cranking out high 10's at 132+. take a properly setup notchback with that much power and 9's are probalby teasing them. can u define "heavy" str8? my buddy has a notch with a full cage, and full interior, basically weighing in the same ballpark as a 350z...not like a new gt500 which are nearly 4k lbs.

essentially though, i think it's the same debate you hear all the time which boils down to people comparing a drag car v sports car.

RudeG_v2.0

iTrader: (1)

A lot of guys in the VQ community struggle to get into the 10's because they don't come to the track with the proper drag setup and are running street tires instead of slicks. Most of those guys also have small twin kits that aren't optimal for drag racing. The fact is a lot of VQ guys don't have a dedicated drag setup like many Supra guys do. Compared to the 2JZ platform, look how many VQ guys balk at the price of a Tilton clutch or at the consideration of a transmission swap. Also, a lot of the VQ guys have BBK's that don't allow for fitment of slicks. If a lot more 600+whp guys ran slicks (and skinnies up front), we would have a lot more sub-11 and sub-10 second Z's and G's IMO.

Hal's car is proof that you don't need more than 800whp to accomplish a low 9 second pass in a Z. Until I see more guys follow in Hal's footsteps and in the footsteps of the 2JZ community, I remain unconvinced that the VQ platform is "not good for drag racing".

ttg35fort

iTrader: (2)

There are a lot of accurate comments in this thread, but here is my input, which may be pretty much a summary of that which has been said, but with some additional information.

HP vs boost:

This will vary depending on various factors:

1. Cams - higher lift and longer duration typically will provide greater peak HP for a given boost level. Longer duration cams typically shift the occurance of peak torque higher in the rpm range, but hold the torque better as the rpms increase. Assuming the same duration and cam timing, greater lift generally provides less restriction of the exhaust flow out of the cylinders and less restriction of the intake flow into the cylinders, and thus greater HP accross the rpm range. Cam profiles and other aspects of the cams also come into consideration, but these are the basics.

2. Turbo compressor selection - if the turbo compressors are operating in their peak efficiency region, the air intake temperature (AIT) will be lower in comparison to compressors operating with low efficiency. That means that the intake air is more dense, and thus lower boost is required to get the same amount of air into the combustion chambers. Also, since the intake charge is at a lower temperature, detonation will not occur as quickly in comparison to when the intake temperature is higher. So, more aggressive timing and/or a leaner fuel mixture can be used in comparison to when the AIT is higher.

3. Intercooler selection - the better the intercooler performs, the more dense the intake air will be. Thus, for a given boost level, more air enters the combustion chambers and detonation is less of an issue for a given amount of air. Also, see note #2.

4. Turbo turbine selection - a larger turbine and/or higher A/R value will result in less back pressure, which allows the exhaust gases to exit the combustion chambers more easily, which in turn allows the intake mixture to flow into the combustion chambers more easily. Remember there is some overlap between the intake valve opening and exhaust valve closing on the performance cams, and if the exhaust back pressure is too high, reversion can become an issue. Thus, lower exhaust back pressure generally results in greater intake mixture flowing into the cylinders and, hence, higher HP. The compromise of a larger turbine and/or A/R is that the turbos will not spool up as quickly.

5. Torque curve - if peak torque comes on early in the rpm range, and then falls off, the peak HP will not be as high as when the torque curve is more linear (generally speaking, detonation will be of greatest concern at peak torque). So, if you can reach peak torque, and then maintain that peak torque through the upper rpm range, the peak HP typically will be higher. The tradeoff typically comes down to spool time. Higher turbine housing A/R values do a better job at providing a linear torque curve, and thus higher peak HP, but the spool up is not as fast as when a lower A/R turbine housing is used. Also, see notes #1 and #4, as both cam selection and turbo selection have significant impact on the torque curve.

6. Exhaust system selection - the less restrictive the exhaust is, the less back pressure. See item #4.

7. Fuel - the higher the octane, the more you can push the motor before detonation becomes an issue. In other words, you can run a little leaner and/or more advanced timing, which generally results in more HP for a given AIT.

8. Dyno selection - Speaking very generally, the DJ dynos read highest for a given setup, while the DD dynos read most conservatively. The Mustang dynos appear to be somewhere in between. e.g., XKR read somewhere around 800 whp with a DD dyno, but somewhere around 1000 whp on a DJ dyno with the same setup.

Blackbird CPV35

iTrader: (19)

If that was true then how do you explain the powerlab G35 that holds the ET Record?

binder

iTrader: (8)

you can take 2 exactly same stock engines and have a 10% difference in power. Imagine when they are built blocks that humans are building. They can vary greatly when you start tinkering.

We've even had factory engines for our race bikes with greater differences than 10% BONE STOCK. SO one will put 150hp and the next 165hp with nothing else changed. It just happens.

ttg35fort

iTrader: (2)

^
Agreed. There are a lot of subtle differences which effect power output.

One thing I forgot to mention above is whether the motor is relatively tight or loose. As a motor loosens (e.g., piston to cylinder wall clearances increase and the bearings loosen up), the motor will produce more hp. Some motors are built loose from the start to maximize hp, but piston slap, etc. may occur until the motor is warmed up. Some say that a tight motor will last longer, which I tend to believe, but I don't have any evidence to back this up.

thom000001

In my opinion (which ain't much I know)....drag racing probably isn't the best overall judge of power performance. Too many variables to keep track of. I was horrible at launching the car....combo of fear of breaking something, no where near enough traction, and just not a drag racer.
HOWEVER even with the horrid launches my car was picking up 50+ mph on the back end! I also have a vid from being out with some supra boys (after my bigger turbos and cams) where a supra that the next week went 10.3@137 I sat next too on pump gas (so power was there on pump....which was in the 630-650rwhp range depending on atmosphere). And I have vid of the car going from 50-135 in 5 seconds flat (on the 26psi setting....801rwhp on SP's dyno).

Like others have said, don't get caught up on the absolute numbers. If you enjoy it, good...there will always be someone faster...

tom

Resmarted

iTrader: (2)

Its stupid to compare a zr1 or a domestic hp to our hp. The way they are geared and the engine produces that hp is totally different. The make all their torque down low and hold it for the most part. They are also geared to move, combined with mainly automatic trannies an usually better drag tires.
The zr1 is straight up an oddball imo. Its like a z06 on crack. z06's are f*cking fast to begin with so... Lol lingenfelter mods to a zr1 yield 500+torque at 2.5krpm and 590 at like 4krpm. No turbo Z is going to have that kind of a wall of torque. Yes the jwt kits can make mad linear torque but it just isn't going to hit that hard that fast for that long...
I agree with the idea that not many cars have dedicated setups so it's not necessarily true to say our cars suck... and i also believe it's difficult to compare to supras with fully dedicated setups. I know this, because I'm practically a pro internet bench racer hahahahahah

Alberto

iTrader: (14)

This isnt even my high boost 500+ft/lbs from 3.5-7K rpms on b!tch a$$ small turbos....

rh_334

iTrader: (2)

This is a 3.5L APS TT Z1 Built

Alberto

iTrader: (14)

Over 500ft/lbs from 3700-5800rpm's, not too shabby. The BC 3 TQ curve is awesome, it doesnt drop till waaaayyyyy high in the rev range.

rh_334

iTrader: (2)

Yea i could live with that curve.
That car had JWTC2 cams, i think thats why it didn't hold TQ any longer than that. This was @15psi, they said it needs bigger coldside housings.

But i feel like these graphs prove that the VQ35 is capable of ZR1 TQ, and ive got to get there quick since my friend is picking his up in a couple weeks

marra23

iTrader: (8)

I realized this jumping into a friend BMW 335i, just gas and it goes....no skill involved.
Around here Z's failed at strip. The guys build theirs cars and make good numbers on the dyno...come race day full of promise and return humiliated, never to be seen again.

Last time out my car made just over 500whp on the dyno and the following week it ran max 127mph exit speeds. How it compares to US dynos and exits

I guess OP trying to establish if his car is down on power and/or hoping the dyno reads low?

Alberto

iTrader: (14)

My car trapped 126mph with me letting off at 490whp on a DD. Your numbers are right on. What did you run @ 500whp and 127mph trap btw? My BS run was an 11.1....

nomyth46

the whole our cars aren't good for drag racing comment was ignorant............all it takes is proper tire, front & rear geometry, and suspension setup and the Z's will eat the 1/4 with the best of them

nomyth46

in wilmywood........gtos floatng around 500whp run 11.7's trapping 122......terminators putting down 600whp running 11.3's...........our cars don't drag race?

shakuya88

I am jealous of some of these power levels I really want to build my block now...lol Alberto, I know you've gone through a couple motors...what do you feel works the best? And would you recommend the BC stg3?

str8dum1

iTrader: (11)

those cars dont run that slow at Fayetteville.

Where's your 10s slip if its so easy? Alberto doesnt even have a 10s slip.

Alberto

iTrader: (14)

edit-TMI

I assure you 600whp @ low boost is 10's, and not a 10.9999 either. Take it for what its worth

thom000001

BC Stage3's are excellent.

Tom