411rwhp from stock internals

[Emre]

GTS-t VSPEC,

Quoting power figures does not mean anything to me at all. You can hardly compare the readouts taken from two workshops in the same suburb, let alone interstate. The shootout mode is gaining a lot of late attention to overcome this dilemna, but as i am not too familiar with it i don't know what to make of those figures as well.

Tell me what you or Rob77 achieved on the strip with the quoted figures and/so i can relate to them. I can put those against what i or my friends achieved and get a conclusion from it.

SydneyKid,

Does the humidty and and temperature have that much effect on the fuel requirements...? If you live in Queensland and the humidity is %70, do you need that much more legroom in your injector capacity ?

It kinda explains though, why i need 124lt/hour of fuel by those calculations, but actually use 194 lt/hour.

[rob77]

Originally posted by Emre

GTS-t VSPEC,

Quoting power figures does not mean anything to me at all. You can hardly compare the readouts taken from two workshops in the same suburb, let alone interstate. The shootout mode is gaining a lot of late attention to overcome this dilemna, but as i am not too familiar with it i don't know what to make of those figures as well.

Tell me what you or Rob77 achieved on the strip with the quoted figures and/so i can relate to them. I can put those against what i or my friends achieved and get a conclusion from it.

SydneyKid,

Does the humidty and and temperature have that much effect on the fuel requirements...? If you live in Queensland and the humidity is %70, do you need that much more legroom in your injector capacity ?

It kinda explains though, why i need 124lt/hour of fuel by those calculations, but actually use 194 lt/hour.

Even when I get a dragstrip time, which I will tonight, how can you compare it to a different car on a different track. There are too many variables. ie: kwinana in perth is slightly downhill or uphill (cant remember which one), each car will have different tyres which will effect traction and 60' times, the ambient temperature will be different (might only make a slight difference), the tracks will be prepped in different ways... they might skimp on the prep tonight and it might be slippery as buggery... dyno's are a tuning aid, sure the dragstrip will give you a better idea of the cars performance, but its hard to compare different strips and run dates.

[Emre]

Hell of a lot more comparable than dyno readouts mate.

Traction has a huge effect on ET's but not much on TS.

[rev210]

the terminal speed will be a good indicator of the power.

At least the owners of each vehicle have a previous terminal speed as a refference, so I'm sure there will be quick validation of the power claims (as relative as they are to the particular car and dragstrip).

I am another who doesn't place alot of emphasis on the dyno as the sole performance indicator.However having had a ride in Robs car I feel confident there is a strong case for defending the power claims from that dyno when he visits the strip this evening.

Cheers

Dave

[Sydneykid]

Hi Emre, I am not a strong believer in the 1/4 as a power indicator either. ET's are too dependant on traction and TS is too dependant on gearing.

An example;

I had a car with 425 rwhp, that was geared for 120 mph top speed. It did hi 11's but obviously at 120 mph TS. It redlined in top gear before the end of the 1/4. The same car with a higher diff ratio ie; geared for 140 mph top speed, did low 12's at 132 mph. The reasoning here is, of the 2 diff ratios available, one was too high and slowed the 1/4 time. We won on ET not on TS, so I went for the lower ratio.

So we have the same horsepower with 2 different ET's and 2 different TS's. How do I calcualte the horsepower of the engine with any accuracy from that data.

Want to get into weight? I know many have read this........

http://forums.vwvortex.com/zerothread?id=776885

Step 1: Baseline

Curb Weight: 2,762 lbs

1/4 Mile:16.3 @ 84.0 mph

60-foot:2.9 sec.

0-60 mph:8.6 sec.

Step 7: Styling

Curb Weight:1,674 lbs

1/4 Mile:14.3 @ 93.2 mph

60-foot:2.6 sec.

0-60 mph:5.8 sec.

Now this car has not 1 horsepower more, but does a 2 seconds faster ET with a 9.2 mph higher TS.

Want to get into aerodynamics and ambient conditions? Me either.

In summary, I have yet to find a perfect method for accurately determining a car's horsepower.

[rev210]

I think the T.S is like a dyno reading a 'relative' indicator.

[Emre]

I hear what you are saying about the gear ratios SydneyKid, but i don't think it is relevant to our scenario. Apart from the LS1 boys with their insanely short gearing in 6th, no one would bother to change their diff ratios on a daily driven car here. Imagine your fuel economy and changing gears like a truck, skipping every second gear.

I am very confident in saying that just about everyone here, keep their gear ratios to the factory spec and don't chop bits of their car to save 1000 pounds.

If GTS-t VSPEC and rob77 went to the track tonight and didn't crack 123-124 and 117-118 mph respectively, i don't have much faith in their quoted power figures.

[Steve]

Originally posted by Sydneykid

..... a good rule of thumb used by many in the automotive business is 1.7 bhp per cc of injector capacity.  Thus 1.7 * 6 * 370 = 377 bhp.

So, I'm still perplexed..........

Sydneykid, I am somewhat mystified too, as my injectors were at 82% duty with 203rwkw and stock fuel pump.

I think there must be something else going on here though, too many people I know have got more power than is theoretically possible with the stock injectors - here in adelaide both BOOSTD and Whatsisname have made over 250rwkw with stock injectors, BOOSTD uses a stock fuel pressure reg, and still has room on his injectors even now with 266rwkw - and is using less than 1 bar boost.

I have driven side by side with BOOSTD, me with a HKS 3037 and 550cc injectors, him with his hybrid and stock injectors - very similar output, and there was nothing in it when we were both on full boost.

Another thing is that whatsisname had his car tuned by the same guy I did, similar power figures, he had stock injectors, I have 550cc.

Why is it that when I say I made xxx amount of power and I had 550cc injectors - everyone accepts it, or at least doesnt challenge it, different person, same dyno, same tuner, stock injectors same output - no one believes it??? go figure.

You are right, it doesnt add up, I like it when things dont add up, as it means that my thinking is being challenged, and an opportunity to learn.

I would dearly love to know why and how, but at this stage all I know is it does happen, not how or why.

The dyno that Paul's car has been run on was tested correct, the same dyno that Rob's car was tuned on, both made what theoretically cannot be done, as people here have. And they arent the only ones who have done it.

There MUST be something in this....... it seems that by adding a high capacity fuel pump (the fuel reg isnt a common factor here) that the stock injectors flow well beyond what they 'should' flow. This is somewhat in line with the fact that alot of people have experienced overly rich mixtures purely by adding a larger fuel pump - which shouldnt theoretically happen as the fuel pressure reg shoud regulate the fuel pressure at a constant.

Ah well, perhaps no one will ever know.

[RNS11Z]

I was on 100% Duty cycle when i made 387rwhp on pump fuel. I have a adjustable fuel pressure reg and a bosch motorsport 0444 (the 700hp) fuel pump. Yet when flowed side by side with another set of standard skyline injectors they both flowed the same @ 370cc. The injectors we tested made 402rwhp on another skyline using a td06-25g turbo (on12psi) and 40hp shot of nos. With out the gas and on 18psi it made 360rwhp (with a very similar fuel set up to mine). So i find it hard to believe for GTST V-spec to make 411rwhp from just turbo, pump, and computer. Then again i doubt myself highly because i dont know too much about skylines and there capabilities.

[Clint32]

No different to rb20s, i have made 235rwkw with stock reg and run 113mph so that is about right, but most people say they are not big enough for that. Im running a 044 so it must help, but pushing injecors with the small pumps like others are doing is a little harder to believe

[GTS-t VSPEC]

Emre, You should educate yourself a bit about the idea of shootout mode, the whole idea is that power figures should be comparable. And seeing as my dyno has been QA'd by Dyno Dynamics then I'm confident with the figure.

[BOOSTD]

Mine has been dynoed at 266rwkw with 95% duty cycle. Standard injectors, Standard A/F meter (runs out of resolution around 4100rpm) Bosch Motorsport pump, very minor porting, Hybrid turbo( with stuff all boost -peaks at 18psi then drops to 13 ) Only one way to find out just how true it is! Drags for me Wednesday night....test out the new Nitto's =)

[Emre]

Emre, You should educate yourself a bit about the idea of shootout mode

I am planning to dude, will definitely have a run on shootout mode next time i strap my car on a dyno.

[GTS-t VSPEC]

Emre, Martin Donnon wrote and article about shootout mode in one of the latest HPI mags, worth a read:D

[BU5TER]

I used to think it was crap too but since reading that article and thinking about it I am convinced that in the not to far future all runs will be done in shootout mode as its a lot fairer and easy to see if someone is diddling the ramp rate etc

[GTS-t VSPEC]

The dyno that i use has been locked, so in Shootout mode no correction factors can be changed, that way you can be sure of getting consistant results.

[Sydneykid]

Hi guys, Shootout mode is SOFTWARE locking not HARDWARE locking, all the usual tricks still work perfectly. Want an extra 50 rwkw? No problems, three turns on the load cell adjuster. When finished, turn back 3 turns. DD guy turns up and checks calibration, guess what? Yep, she's 100% accurate.

Want another one? In Shootout mode the PC does temperature compensation. When it's a hot day it increaases the power reading, vice versa when cold. Wanna trick it? Easy stick the temp probe in cup of warm water while you do the power run. Bingo extra 15% rwkw.

Want another one?

Nah I think I made my point.

[GTS-t VSPEC]

Sydneykid, I love your sceptical attitude, but I think I may have noticed the temperature probe in the hot water;) Yes you still can get unscrupulous places doing things like that, but is it really worth there while?

[JimX]

It is definitely worth their while, if they are tuning cars whose owners don't know any better. People will look at the dyno readout and think the tuning shop is better than the competition, just because their dyno readout is better.

Think about it - all other things being equal, which are you more likely to go back to? The one that says your car puts out 200rwkw or the one that says it puts out 230rwkw?

[N I B]

I tuned this car and we have Dyno Dynamics in WA this week.I'm happy to let them run this car up while their here if it will stop all the knockers. The East coast needs to lift their game and match us West Ozzies!