75 shot, stock turbo, 91 pump? - SRT Forums

**04blusrt_4** · 12-09-2008, 07:39 AM

Can you run a 75 wet shot on 91 pump at +20psi on stock turbo? Can I expect to have a lot of knock?

SRT-4_UK · 12-09-2008, 08:03 AM

are you doubting me?

**04blusrt_4** · 12-09-2008, 08:07 AM

Not doubting, researching, i went through this already for months, with endless people posting to me telling me i was moron to spray on pump gas and they never would.

I tried it, knocked like crazy. I had a 75 shot on a stage 3 turbo, thats prob. the difference, couldnt handle the added CFM on 93 pump. I still have doubts you had ZERO knock, i dont see it in your dyno shots, i only see AFR and boost. Either way, I want other opinions. I lowered it down to a 50 shot, still knocked (5-6* near redline). Even on a 35 shot i still had 3-4* of knock.

**04blusrt_4** · 12-09-2008, 08:13 AM

Read up on this thread, some of the most experienced nitrous guys chiming in.

What Octane while spraying?

Hope your not a plug reader like the last guy, post up some datalogs

04inred · 12-09-2008, 08:16 AM

Just turn the boost down. If you run 15 psi and the spray that should workout the knowck and the power. You will get a 100+ hp out of a 75 shot and 125+tq.

**04blusrt_4** · 12-09-2008, 08:22 AM

Quote: Originally Posted by 04inred

Just turn the boost down. If you run 15 psi and the spray that should workout the knowck and the power. You will get a 100+ hp out of a 75 shot and 125+tq.

You mean on a stock turbo? For me (stg3 turbo) that doesnt make sense, at 15psi I will loose about 60whp and only gain back 100whp, net 40whp and be spraying nitrous.

I agree it will enable me prob. to run nitrous on pump gas, but its not quite the same power argument anymore.

SRT-4_UK · 12-09-2008, 11:43 AM

Quote: Originally Posted by 04blusrt_4

Not doubting, researching, i went through this already for months, with endless people posting to me telling me i was moron to spray on pump gas and they never would.

I tried it, knocked like crazy. I had a 75 shot on a stage 3 turbo, thats prob. the difference, couldnt handle the added CFM on 93 pump. I still have doubts you had ZERO knock, i dont see it in your dyno shots, i only see AFR and boost. Either way, I want other opinions. I lowered it down to a 50 shot, still knocked (5-6* near redline). Even on a 35 shot i still had 3-4* of knock.

Stg 3 turbo is really different from the tiny stocker. Also, what were you using as a computer?

**04blusrt_4** · 12-09-2008, 12:25 PM

Quote: Originally Posted by SRT-4_UK

Stg 3 turbo is really different from the tiny stocker. Also, what were you using as a computer?

Stage 2 pcm.

Rhunter · 12-09-2008, 09:33 PM

Looks like you have done your home work. It also looks like you have answered your own question. Heck dude, you know and have put more research into this then I have, but I would NEVER spray a 75 with my stock turbo on 91 piss water.

NJ DSM · 12-09-2008, 09:48 PM

Why spray on pump gas...race gas isnt THAT hard to get...

just asking for problems

Rhunter · 12-10-2008, 05:00 AM

Quote: Originally Posted by NJ DSM

Why spray on pump gas...race gas isnt THAT hard to get...

just asking for problems

X2. If I could'nt afford a couple gallons of race gas, I would'nt mod my car.

04inred · 12-10-2008, 11:33 AM

Shit sorry didnt read the S3 turbo part. Get rid of the S2 pcm and get a tune (deablo,SCT) and you will be good. You could have it tuned to run on E85, thats option.

**04blusrt_4** · 12-10-2008, 12:31 PM

Thanks guys, I posted this up to let SRT_UK guy see that it is not recommended to run nitrous (esp. not a 75 shot) on pump gas, on a stock turbo + staged computer. Looks like I still have the support.

Rhunter · 12-10-2008, 01:32 PM

Quote: Originally Posted by 04blusrt_4

Thanks guys, I posted this up to let SRT_UK guy see that it is not recommended to run nitrous (esp. not a 75 shot) on pump gas, on a stock turbo + staged computer. Looks like I still have the support.

Heck man. S3 on nitrous should be a fast as all get out!!! If he's looking at running that much boost, he could start with a smaller shot, monitor knock and A/F while progessing to a bigger shot. OR just keep it at 50 and tune it with the fuel pill. That should make for a very fast car.

SRT-4_UK · 12-10-2008, 08:32 PM

Quote: Originally Posted by 04blusrt_4

Thanks guys, I posted this up to let SRT_UK guy see that it is not recommended to run nitrous (esp. not a 75 shot) on pump gas, on a stock turbo + staged computer. Looks like I still have the support.

Well you sit back and bench race it and I will stick to what I have seen on the dyno. 0 knock with the exception of the initial boost spike and I was keeping a keen eye on my a/f ratios. Thanks for being concerned for me tho.