427TA

I'm working on a nitrous setup for my 427 LS3 and a buddy of mine was telling me that the compression on my motor was too high to be running nitrous and 93 octane pump gas. I'm planning on running a 200-shot, possibly dual stage. My motor has a static compression of 11.8:1.

I figured that just pulling a little more timing than normal while tuning the car would make up for the higher compression. Am I correct in assuming this, or does this not work with this big of a shot or nitrous in general?

soundengineer

iTrader: (16)

nope.. no such thing as too much compression for Nitrous....
High Compression and Nitrous get along Great...

I'm 11.2:1
Running 93 octane pump gas
and currently spraying a 350 shot with no motor issues.......
traction is a different story(part of the reason I'm changing chassis's)


you can actually pull less timing that you would think is necessary, but its better to start out low and work your way back up...

10secZ28

iTrader: (6)

fwiw i had a 13.1 402 on a 250 shot and ran it on 93, kept a really cold plug in it and was very soft on timing

Chris@NitroDaves

Nitrous loves compression!!!!!!

n2ols1cam

350 shot on 93 octane?? What plugs are you running? Please help me do that, I'm about the same compression as you and I run c16 on a 250 shot.

Sales@Tick

iTrader: (3)

It's too much of an open statement to say nitrous loves compression without including the amount of timing or dynamic compression used in the set-up.

It does love compression, but the type fuel you need to use will change.

I personally would be wary of running 11.8:1 on 93 with anything more than a 200 shot, as long as the dynamic compression wasn't over 9.0:1 which will take a good sized cam to keep it under there.

I think the amount of total timing used and dynamic compression while spraying these size shots on this much compression would be a good idea to add to the information some of you guys are giving just so the OP knows what he is in for. Tuning window will be small that's for sure, but it can be done.

I know ATV_racer and Shiznity did this in the pump gas drags and IIRC they were nearly 12:1 and used water injection IIRC.

ShiznityZ28

iTrader: (11)

In my opinon from the 10-15 LS motor setups we have had and ran. The amount of compression matters far less than chamber design and tunning methods.

BottleBoy1

It will be okay if the tune is okay. I have gotten away with more than that. As also mention it depends on the cam as most end up bleeding off a lot of cylinder pressure. I ran 225 on 93 with a Autolite AR 93. I'm sure I will hear flack cause I'm NOT on the NGK band wagon. BUT we have been running the Autolite AR race plugs in ALL of our stuff for over 12 years now with NO issues. I would also tighten the gap up to 26-28ish. Differnt brands of pump gas Also have a MUCH different octane rating as ambient temp. cahnges. I haven't seen a good study or test on that in years. But the last 1 done had Texico rated top & Sunoco second.

dtroike

iTrader: (4)

If you want a little extra safety you can do what I did and run a stand alone system. I run 91 in the main tank and race fuel in the stand alone. Takes some of the demand off your intank pump too if you are pushing it already. I am only running a 125 shot with 11.6 scr, #7 plugs, 250's cam. Im also running at 4500ft.

soundengineer

iTrader: (16)

Static Compression around 11.2:1
cam is HUGE ------ 252/274
Dynamic Compression is around 7.4:1
Cranking Compression is around 180psi
#9 Plugs

with the mustang, theres going to be a Meth Kit and I'll be hitting it with a 500 shot