BR EVOX back at the track...........many "what-not-to-do's"

[David Buschur]

Where do I start this thread......so many things on my mind, too many after thoughts.

Let me start by first saying the best our EVOX ran on stock engine/head with our Stages 1-3, plus ported exhaust manifold, stock 02 housing ported, Cosworth cams, Blouch Dom 2.0 and pump gas was 11.71 at 124.xx mph. The car would not leave the line very hard back then and we never figured out why, it was also out of gear to finish the 1/4 mile in 4th gear.

Flash forward to our winter project.

BR Stg 3 shortblock, BR Stg 3 head, BR T3 turbo kit with Blouch GT600R turbo and a final drive change to drop the RPM.

The result of these changes were GREAT power on 93 octane, here is one of the dyno graphs from the initial tuning. I was actually able to hit 525 whp with the current tune that is in the car:



Two weeks ago we took the car back to the track, Kevin drove, I drove. Both us of turned 12.33 in the car, the car would only bog and not leave the line. Kevin being the excellent driver he is noticed the two step was at 5500 rpm. Interesting as I had it set to 6800, after a few attempts I realized something in my ROM was wrong and it was not adjustable. That explains it never leaving the line well. After posting the problem I was helped by a number of people in the stock ECU section and the problem with the two step was fixed.

Last night I took the car out to the track by myself. I made three passes, the best of which was an 11.67 at 126.23 mph, the best 60' was 1.77 with a slight bog half way through the clutch release. I'm no Pro driver and that's why I have Kevin and Trent drive for me. I am capable of running a mid 11 second 5 speed about as quick as anyone though, it's when they are really fast that I can't compete. So I am not blaming the performance on my driving as it wasn't really that bad. No powershifting but shifted as quickly as I am capable of. The car is at absolute full weight and had about a 1/2 tank of whatever pump gas was put in it last, 93 octane from somewhere. 29 psi peak boost, 0 knock counts on the entire run. Injectors are at 97% duty cycle, I'm running ID1000's.

So on to my after thoughts.

The stock gearing in the EVOX combined with the stock shortblock and a good amount of power sucks, the car simply runs out of gear before it can finish the 1/4 mile, which was the case last year. In my big list of desires was to fix the RPM issues and install a different final drive. My problem was my thought process as I was not considering at the time I was going to be building an engine that would run to 10,000 rpm and putting a large turbo on it. This combination doesn't work, never has.

The gearing in the car is so tall now that it keeps the car out of it's power range. If you take a second to view the graph the car makes very good peak numbers. The problem with the EVOX's are I have not seen one personally that has a BIG FAT power band, so it has to be run high in RPM and when it shifts it drops back out of power. Not a good drag car.

The gearing is so poor in the car now that I do not need to shift to 4th gear until the finish line is coming up and I'd guess after 1,000 feet. The EVOX stock with 400 whp is in 4th by the 1/8th mile. Same story for the EVO8-9's.

The interesting thing is the top end power after the 1/8th mile and this is where the car feels freaking strong. At the 1/8th mile the car is running only 91.56 mph by the finish it's gained 34.67 mph, this is HUGE in the back half of the track.

I am not gutting this car and I am also not trying to turn it into a drag car. I do feel though that drag times/mph are a very good indicator of how a car is working and the power it makes. In this case the combination of the tall gear and the large turbo with a peaky power band just doesn't work.

Now for my dilemna, to change to the stock gear ratio again or to drop down to a stock appearing turbo again.

Anyone looking to trade a fresh EVOX trans with the tall final drive and some cash for their stock transmission?

Our new best for reference is:

1.777 sixty foot
7.65 at 91.56 at the 1/8th mile
11.676 at 126.23 at the 1/4 mile

[Weapon X]

so do you think the taller final drive would be better for a car with an upgraded stock frame turbo like a red or a dom? it would be interesting to see some side by side data if you swapped the dom back over and made a few more passes.

and for reference, what do other 500ish whp X's from your dyno run in the 1/4?

[EVOFans]

Try stock gear and get the best out of this setup,I would like to see some fast EVO X coming out of buschur

[Poondogggs]

David:

Why was the car bogging down when you ran the quarter previously? I take it it was something in the tune, what was it?

[David Buschur]

Car was bogging before because the two step would not go over 5500 rpm.