Okay i have a ls1 in a 93 pickup it has been doing fine I put new heads on 5.3s running great. Well i later put 9 gallons 93 and 4 gallons 110. Well after running a truck in town my truck started to pull on its own like cruise well stoped and turned it off restarted and it reved up like hell. Well disconnected the iac and now it idles and i can turn it off and restart no problem. My ? is will race gas cause this if it is not tuned for it. I have had the computer programmed. It seems as if the race gas does this to it. What do you guys think? Thanks for any help sorry if wrong forum.

 

race gas has lead in it, now you need to replace your O2's.

 

So how does people run this gas with the o2s. I am about 12.1 compression on 5.3s milled .020. With a .591 .569 lift cam. So why would it change when i unplugged the iac it does fine? Any help thanks

 

Race gas cannot be used arbitrarily like that. Sorry, man.

 

sorry but what does that mean? So is that my problem the race gas and do yall think the 12.1 will be fine on hot 96 degree days but most of the time my truck is driven at night when it is cool out. With just 93 octane

 

:yup:

need to run a lead friendly o2 or run 100 octain unleaded.

 

So does anyone run race gas and what kind are you running? thanks for all the help guys so i should drain my fuel cell and replace my o2s. What can i mix with the 93 octane?

 

personally i would say lower your timing so you wont need it, but if you must use race gas just make sure that its unleaded. i think 103 is the highest you can go unleaded, and its expensive.

 

Yeah, just make sure you buy Unleaded Race Gas and you should be ok.

 

So the leaded gas and the o2s have somthing to do with the idle going crazy but with the iac unplugged it is fine. Does the o2s control the iac aswell?

 

If you unplug your IAC then your motor won't rev or surge because the computer it has no control over your throttle blade. It also won't be able to adjust itself if needed.

 

is that cause of the gas? Iac gets controlled by what the o2s are telling the computer right?

 

You should add that to your LS1 FAQ if it's not already in there. Iv'e seen too many make that mistake.

 

Theres a 105 unleaded race gas but expect to pay for it out of your ***. What are you running race gas for. Does your car really need it?

 

ya, 100 unleaded is like almost 6 bucks a gallon here, no ****** joke

flippin, give me your full engine and cam specs and i'll try to figure out your SCR and DRC

i need:

gasket thickness
deck height
advertised duration of the cam
lsa and icl

 

Try a good waterinjection kit like Snow performance and you'll probably be able to run
92 octane. After installing mine the timeing was increased 2* and injectors richened up
6% I can run regular!!

 

Hey jrp i will try my best I have a ls1 5.7 with 5.3 heads milled .020 comp r lifters. F1 cam .591 .569 on a 112 the head gaskets are the stock ones from the local orielys fel-pro gaskets. Stock bottom end. Stock valves in the 5.3s but a good valve job done. Also i am running 7.4 comp pushrods. I think they might be to long cause if cruising for a few minutes at about 50mph i start to hear a really loud ticking coming from the engine but wheni stop for a few seconds and start going again it clears up for a lil bit. Has to be either the pushrods too long or rockers are messing up but they look fine or my new $200 comp lifters suck. Maybe i should make a new post for that last ? thanks guys for all the help you have been giving me.

 

guestimating i come up with 8.6 to 8.8 DCR thats a little high IMO for just straight 93. whats your timing curve like and any KR? what steps did you take to ward off detonation? a 50/50 mix of 93 and 100 unleaded should yield around 97 octain.

 

If you don't get any knock retard than race gas is not needed. People think that there gonna run race gas and gain something. It is best to run a lower octane fuel over a high octane fuel if you have no KR.If you don't ping and don't get any KR ,stick with pump gas. You can loose power by running race fuel when it's not needed

 

my buddy pumped 100 octane for like $4.3x a gallon. i thought that was expensive