Exhaust Drag Race Questions

[VKPWR]

Hey Folks,

Anyone here got any facts/experience on benefits from dropping the exhaust system when racing on the ¼ mile?

I am questioning whether I can be bothered dropping mine in a couple of weeks at Calder Park.
Application in question:
VY Calais, LS1, CNC 243 heads, 11:3-4 comp, 224/230 stick, DiFloppo 4 to 1’s, 1 ¾ with 3 ½ inch single exhaust system, built auto, 3500 stall, 3.9 diff. – makes like 290 kw or something at the wheels.

Thanks in advance.
Brad

[hurricane]

hi mate,i would just go out and enjoy and have fun. a lot of messing around to drop the exhaust plus it would be bloody loud in the car.

[amckiwi]

Exhaust also gets bloody hot, you would have to wait until its cooled down before dropping it.
You will need a jack stands or ramps
Seems like way to much work to me.
Stu

[Wonky]

Unless you're aiming for every hundredth of a second I wouldn't bother. I know someone who had exhaust cutouts welded into his 340+rwkw VE to save the effort of dropping the exhaust and they made SFA difference on the track. Very, very slight possible gain.

[Micks]

My advice if you have a 1/2 reasonable zorst now going a straight through will net you no marginal increase! Some back pressure is good!

[ittwgn]

I have thought about dropping mine but havn't yet it is turbo so better to have no exhaust at all !!! the other reason is weight dual 3 inch with cats and mufflers when I took mine off must have been 30 to 35kg or so every bit helps if your chasing 1/10ths

[VKPWR]

Hey Folks,

Anyone here got any facts/experience on benefits from dropping the exhaust system when racing on the ¼ mile?

I am questioning whether I can be bothered dropping mine in a couple of weeks at Calder Park.
Application in question:
VY Calais, LS1, CNC 243 heads, 11:3-4 comp, 224/230 stick, DiFloppo 4 to 1’s, 1 ¾ with 3 ½ inch single exhaust system, built auto, 3500 stall, 3.9 diff. – makes like 290 kw or something at the wheels.

Thanks in advance.
Brad

well i went to calder, exhaust on, wacked the ET streets.. and now not sure if the time is decent.. Ran best 12.27 @ 112.9 MPH with 1.78 60 foots....

any ideas to lower 60 ft n go 11's?

I thought it may have been good for 1.60 60 ft.. obviusly not, 3 runs and all pretty much the same.

[munz]

What RPM is it revving to?

[offshore]

Id get a race setup made so straight from the extractors about 18inch from the collectors which is about what the DF opens are anyway I think then join the two on one side and then 4 inch straight out the side behind drivers door. Wouldnt cost much not a great deal of pipe involved

[ittwgn]

well i went to calder, exhaust on, wacked the ET streets.. and now not sure if the time is decent.. Ran best 12.27 @ 112.9 MPH with 1.78 60 foots....

any ideas to lower 60 ft n go 11's?

I thought it may have been good for 1.60 60 ft.. obviusly not, 3 runs and all pretty much the same.

90/10 shocks go bigger 4500 or so stall will help 60ft take out weight front runners etc

[white lie]

What wheels are on it?
How was the traction and what pressures do you run (front and back)?
What suspension is in it? How low is it?

Bigger converter will definitely get it there but there's a few smaller things to try before ripping it out.

I don't think there will be bugger all in it by changing/dropping the pipes. Not worth the hassle anyway. Get that 60 footer down to a 1.6 and it will run a high 11.

[dogsballs]

doubt you will gain anything from dropping the exhaust, may even loose hp if the car is tuned with full system with a bit of back pressure. main benefit would be dropping some weight.

1.78 60ft isn't bad for a 3500 and 3.9's, unless you had 400+rwkw you'd struggle to do 1.6's.

need 90/10's, fe2 rear shocks/springs, bigger convertor 4500+ and 4.11's to get into 1.6's. i've got to 1.51 with that combo and ~290-300 rwkw in a vz on a 235 radial

[VKPWR]

had 19s on the front @ 40psi, MT Et street on 15/6 ceptors and I ran it on 20psi, first run had a little sqeak of lost traction other than that full hook up.

lowered suspension, KYB AGX in rear went from setting to to 3 with SSL 's so its kinda low.

cam certinly doesnt do the heads jsutice but its daily driver..

What wheels are on it?
How was the traction and what pressures do you run (front and back)?
What suspension is in it? How low is it?

Bigger converter will definitely get it there but there's a few smaller things to try before ripping it out.

I don't think there will be bugger all in it by changing/dropping the pipes. Not worth the hassle anyway. Get that 60 footer down to a 1.6 and it will run a high 11.

[VKPWR]

might be revving it to hard. shifting at around 6400, but did shift round 6700 once or twice.

I had auto shft raised from 6000 to 6400 in 1st and 6500 in 2nd and 3rd ...maybe 6000 shift...

Still rekon its doing on for the setup.. was fun anwyay...

[white lie]

Height will be a major restriction. Jack it back up, stock fe2 gear will do for now.
And put more air in the front tyres. Wont affect your 60's but too low pressures will hurt your MPH.

Do you run filter in or out?