Digsy's big horsepower versus performance survey.

Right-ho.

As a result of the "transmission losses" thread, I'd like to try to get some kind of a feel for what the real losses through the Supra drivetrain are.

For this I will need input from people who have run their car on a rolling road or hub dyno AND IN THE SAME STATE OF TUNE done a 1/4 mile timed run, with a recorded trap speed.

This is for measured data only, so no speculation, please!

To make my life easy, please respond in the "cut and paste" method used in the gathering type of threads.

You will need to specify the following:

Transmisison type.

1/4 mile time

1/4 mile trap speed

Intermediate times and speeds.

"Measured" horsepower. State whether this is rear wheel, hub, or a calculation of flywheel based on either. Out-and-out estimates are meaningless for the purposes of this survey.

I'm hoping we can get some kind of a trend of driveline losses versus power to use in future calcs.

Here's Chis's car as your starter for ten:

Transmisison type: 6sp manual

1/4 mile time: 12.71

1/4 mile trap speed: 123mph

"Measured" horsepower: 623 (estimated @ flywheel)

-- Jake --

Transmisison type: 4sp Auto (not Tiptronic)

¼ mile time: 13.340 (Santa Pod)

¼ mile trap speed: 116.27mph (Santa Pod)

"Measured" horsepower: 350.5 RHHP (Thor Racing)

"Measured" horsepower: 301.9 RWHP (Surrey Rolling Road)

EDIT TO ADD @ DIGSY'S REQUEST :

JohnK ==================== Jake

2.378 ------ 60ft ------- 2.624

6.078 ----- 330ft ------- 6.374

8.971 ----- 1/8 ET ------ 9.116

87.18 ----- 1/8MPH ------ 90.96

11.468 ---- 1000ft ----- 11.355

13.701 ---- 1/4 ET ----- 13.340

103.94 ---- 1/4 MPH ---- 116.27

14.1 @ 103 mph or 14.3 @ 105?! (dunno what you wanna take from that)

6 speed Manual

265 @ rear wheels (G-Force Ayelsbury)

309 @ hubs (Thor)

EDIT TO ADD @ DIGSY'S REQUEST :

Bobbeh =========

2.356----- 60ft

6.217--- 330ft

9.311--- 1/8 ET

80.68 ----- 1/8MPH

11.892 ---- 1000ft

14.160 ---- 1/4 ET

103.66 ---- 1/4 MPH

Digsy - are you after the best trap speed or the best 1/4 time? As the trap speed is supposed to be the indicator of power... And my best is 129 at 12.89s

-Ian

Digsy - are you after the best trap speed or the best 1/4 time? As the trap speed is supposed to be the indicator of power... And my best is 129 at 12.89s

 

-Ian

Unfortunately, the maths is coming apart around my ears at the moment. I always knew that assuming acceleration to be linear over the 1/4 mile would introduce an error, but unfortunately the error is way too large. It must have been pure coincidence that it worked for your other 1/4 mile run. The figures that you just posted don't work, though.

Balls

I need to find a way of getting the residual acceleration as the car crosses the line. I might be able to get it if people post up their intermediate times, as you get at Pod, but I'm guessing that not everyone will have these.

HOLD UP A SECOND

I've just realised that I'm going to be able to do a lot more with this data if you include intermediate times. If you have them, please edit your original post toinclude them. If no, please post anyway - it'll make an interesting database.

Fastest cars will be geared for a low top speed, so they get to that speed quicker but cross the line at a slower speed than the losing car! That's gonna be a PITA to calculate without massive errors I'm afraid!!

Fastest cars will be geared for a low top speed, so they get to that speed quicker but cross the line at a slower speed than the losing car! That's gonna be a PITA to calculate without massive errors I'm afraid!!

That's why I need to be able to accurately work out how much the car is still accelerating by when it crosses the line, as well as the trap speed.

Are you not worried about varying conditions as well?

Surely the fact that driving up a 1/4 mile strip at 100 odd mph is going to create vastly different inlet air than a big fan stuck in the front of your car at a dyno?

Or will the environmental differences not cause enough of a change to worry about?

Transmisison type: 6sp manual

http://homepage.ntlworld.com/colin.lewarn/timeslip.jpg

The above measured at santa pod

"Measured" horsepower: 292 bhp (at the wheels)(powerstation)

Stock sized wheels (255/40/17) 25 psi pressure

I change up at the red line in each gear and go over the line in 4th gear just before the rev limit.

Stock body no polystyrene bits or spare wheel

Driver weight 63 kg

enough info

Are you not worried about varying conditions as well?

 

Surely the fact that driving up a 1/4 mile strip at 100 odd mph is going to create vastly different inlet air than a big fan stuck in the front of your car at a dyno?

 

Or will the environmental differences not cause enough of a change to worry about?

Yeah, they will play a part, but I'm still interested to see how this pans out.

Auto

1/4 mile 13.5s

1/4 terminal 108mph

estimated 360-380bhp @ the fly, prob 300 @ the wheels/hubs

estimated 360-380bhp @ the fly, prob 300 @ the wheels/hubs

Is that estimated from a RW or hub figure? I need it to be based on something physically measured. And do you have any intermedtaie times or speeds for the 1/4 mile run?

Sorry Digsy thats a guess at the bhp from the mods I have on. I did dyno it when i got it and got 323bhp @ the fly.

heres the full time slip

60ft 2.370

330ft 6.066

1/8 ET 8.946

1/8 MPH 85.87

1000ft 11.353

1/4 ET 13.504

1/4 MPH 108.2

Cheers, dude.

Keep 'em coming

Transmisison type: 6sp manual

http://homepage.ntlworld.com/colin.lewarn/timeslip.jpg

 

The above measured at santa pod

"Measured" horsepower: 292 bhp (at the wheels)(powerstation)

Col, which of those times is yours? The left or right?

Col, which of those times is yours? The left or right?

This might help

Cheers, Jake. Bobbeh already told me Col was on the left.

Here's what I have so far, then: From what's been posted I can indeed work out the residual acceleration as the car crosses the line. So far its in the order of 1.5 to 2 m/s^s. Initial acceleration is around the 5 to 6 m/s^2 mark. As you can see, I need both the 1/4 and 1/8 mile times AND speeds for each car.

Hopefully when I bang those into the power spreadsheet (which is at work) things will start to make more sense.

*EDIT* This is the first time I've ever had to use calculus in the real world. You b*stards

Supra 0.25 mile times and accels.zip

Digsy, you need to amend my info if you're gonna use the 60ft data I supplied you, as that was for the 14.1 time @ 103.

do you need power figures or can you do without?

neve been on dyno, if people asked i always estimate 380-400 hp flywheel

SUPRA TT auto 96

11.962 @ 114.17 mph

60 ft 1.730

330 ft 4.964

1/8 et 7.660

1/8 mph 91.11

1000 et 9.924

(stock turbos stock 440cc injectors no boost controller or fuel comp @ 1bar boost)

ps to colsoop you not on drag list you want to send me some info and will stick you up on list

digsy what you planning on all the numbers

ps dont know if this will help, there is a detailed list of supra drag times

http://list.to4r.com/

ps to colsoop you not on drag list you want to send me some info and will stick you up on list

He is actually Mark

Dragracing Times For Stock & Hybrid Turbos

 

...

27. 13.414 @ 110.55 mph Colsoop (6TT) JAP (Santapod) standard 16`s

He is actually Mark

Updated with Bobbeh's correct figures.

Monkey: I'm trying to do a correlation between dyno figures and performance to see if I can make any sense of the power adjustments that dyno operators apply to their rear wheel figures. Unfortunately this means that I must have a timeslip and a measured dyno power figure, rather than a guess.

Updated with Bobbeh's correct figures.

 

Monkey: I'm trying to do a correlation between dyno figures and performance to see if I can make any sense of the power adjustments that dyno operators apply to their rear wheel figures. Unfortunately this means that I must have a timeslip and a measured dyno power figure, rather than a guess.

good look on your headache

I just realised I can add to this.

Stock SZ auto

60ft 2.527

330ft 6.975

1/8 ET 10.547

1/8 MPH 70.21

1/4 ET 16.175

1/4 MPH 87.49

163 RWHP (Clive Atthowe)