A few months ago after finally getting my dssracing forged bottomend broken in and tuned. My tuner and I found that I had excessive backpressure for a fairly simple 3' exhaust. I was peaking about 8lbs of pressure at my wideband location and that was with my dtp rear dump open. I hit a max 699whp and 650tq @ 19lbs boost with 50/50 water/meth on 94 pump gas. EVERYONE was blaming the poor On3turbo as the culprit for my less than stellar numbers and poor turbo efficiency.

I made a few threads about upping my exhaust flow and came up with adding a larger 4' cutout at the rear...and adding a fender exit 2.5 loudvalve right off the turbo to add in ridding the backpressure. I must say the loudvalve was an instant response in performance. The car flatout was making more boost early and unruly torque. I tried to make a pass and did some street pulls which netted me a leaking rear axle. Since then I fixed the axle..switched to a Lingenfelter 2 step to replace my old msd unit and build more boost off the line,and a linelock. My tuner saw video clips of me booting around and knew I needed dyno time.

Which brings me to yesterdays events. I had time off to make it over to Champion motors and strap the car down. With no changes to the tune..we saw immediate gains at 14lbs especially the midrange hp and torque! At the end of it,for the first time..the flame shot a hot flame from the fender and I was happy. 19psi peak made 766hp/811tq, 92% duty on my deka #80s, and my aeromotive fuel regulator isn boost referenced yet..set to 58lbs. There is more in it we figure adding more fuel uptop,a splash more boost and crack 800whp. Checkout the video and some other cars while I was there for the day.

 

that's killer for pump gas on 16psi.

i'd be looking into an 8.8 swap soon, that 7.5 is gonna asplode

 

I thought for sure I killed the diff last time at the track. I've been super extremely lucky on the stock 10 bolt. It is a 94 lt1 rear but I don't try to hook it up hard from a dig. That's been saving me for now. I know if lower my tires and try to 2 step launch....i won't make it to the 60ft mark.

My issue is what replace it with and still keep stock wheels and my current brake setup.

 

Nice work. Glad it worked out.

 

is it 3 channel or 4 channel abs?

last year I narrowed and put a hiltsy mount on an 8.8 for a local guy and it ended up working out really well. He used the bolt on type spacer/bolt pattern adapters and kept the same wheels.

I think the stock 3rd gen rear is (dont quote me) like 59" and a narrowed 8.8 is 56" or so. There's a couple guys running them on here hopefully they chime in

 

 

Really digging that torque. But I'm afraid that will soon be the 10 bolts undoing, especially if you are using a ceramic type of clutch. If it doesn't let go on the dig, the 1-2 shift will be it. Love your results btw.

 

To answer all the questions above:

The 94 diff i put in was a 3ch abs system. I want to keep weight down but have a decent diff in the future. I might do a s60 as a common fbody guys do.We will see.

The msd 2 step i had previously would maybe build about 2-4psi depending on the rpm setting. I guess it depends on exactly how these controllers limit spark etc. The lingenfelter builds consistent 6psi and I liked the ability to have no lift shift feature. I also replaced the msd unit twice causing random misfires and stuttering/popping issues. Just didnt trust the quality anymore

Im running the monster lt1-s twin disc clutch. I know at anytime if i hard launch or shift the 1-2.. it will be the end of the run. on the street I dont worry because all the car will do is haze the tires. At the track..the 10 bolt will tell me to f*#k off! the midrange torque when the loudvalve opens and boost hits is insane. As im getting used to it..I notice myself holding my breathe till I let out!