drptop70ss

I am putting an LT1 into a 65 olds and will be using long tube non emission type headers. Since there are no EGR hookups and I dont need the EGR on a 1965, I am going to remove and block off the EGR to clean up the engine. Will the removal of the EGR force me to run 89 or better octane gas? I have been running 87 in my 94 with a stock LT1 no problem, will the loss of the EGR gas cause detonation? Anyone still running 87 with the EGR blocked off?

95z28man

You should always use 93 in an LT1 no matter what.

drptop70ss

Not really, the whole idea behind the reverse cooling is to cool the heads first, keeping the combustion chamber cooler and allowing the engine to run on 87 octane even with relatively high compression. EGR also helps by cooling the chamber, I just want to know if people who have removed the EGR noticed any difference and may have had to step up to higher octane. My 11:1 427s get the 93 octane, my stock LT1 engines dont, in fact my 94 ran nicely all summer on 87 grape juice. It may get more igntion advance with 89 but I dont run the car hard enough to warrant it.

Kevin Blown 95 TA

The EGR comes on in cruise and when you are lugging the car and the timing is kind of high, then you need to see if it has any pinging or timing retard, then if it does, you need better gas or less timing (or EGR). When you run the car hard, it doesn't come on. If you have programming capability, you can control the EGR parameters and timing as you probably know.

drptop70ss

Hi, no programming stuff yet, but it is on the list of things to get, all depends on how many of these conversions I end up doing. Right now I am working with stock engines so no need to do a lot of tuning. For now I guess I will try it with 87 and watch the knock counts with a scanner until I can upgrade to some software on a laptop, if it doesnt look good I will bump it up to 89. I just dont want to hurt the efficiency of the engine, the whole idea of the conversion is to put together an older car that I can drive everyday and still get decent performance and milage.

Injuneer

Take the time to read an LT1 Owner's Manual. It notes that the engine is tuned to run on 91-octane fuel, and that if you use less than that, you will probably lose performance due to retarded timing. Won't damage the engine, but it will affect power. If you live at an elevation substantially above sea level, or if you live where inlet air temps are relatively low, you can run a lower octane fuel. Unless you run a scan, you will never know if the PCM is pulling timing.

Without EGR, you may see the PCM pulling timing, if you are lugging the engine at low RPM, even when using the recommended fuel. Since you are already using a poor quality fuel, less octane than the engine was tuned for, you may experience a level of detonation that exceeds the ability of the PCM to pull timing (15* max, on a stock tune).

Kevin Blown 95 TA

That sounds like a logical plan. Will add that I also agree with Fred, though.

drptop70ss

Thanks..Injuneer, if I were running the car hard I would put the 91 in it, but I run these cars pretty easy, almost never above 3500 and only been wide open throttle maybe once. I do a lot of light throttle cruising where EGR would come into play so I will just keep an eye on the scanner for now.

EastonBall

Why would you go through all this trouble just so you can run 87 Octane gas? I'm sorry if I sound like a jerk, but in all reality, it's just a few more cents. It's the muscle car way... pass verything but a gas station. Why don't you just use the recommended 91+ and be done with it?

drptop70ss

Not going through the trouble just to run 87, I have plenty of engines that will run on 87. I am doing the conversion to have a daily driver 65 olds with fuel injection and acceptable gas milage, it is still an aerodynamic brick but I want to try it. As far as octane, running anything more than the engine needs is a waste of money, few cents or not, but really all I wanted to know is if the removal of the EGR system caused anyone detonation issues that required stepping up the octane. If 89 works fine with the EGR removed then that is what I will run. If I take it to the track then 91 and up will go in.

Vicious95Z28

Are you 75?

Also, when you say "Not really" TO THE NEED FOR A HIGHER OCTANE FUEL, IT'S LIKE SAYING THAT THE GUYS AT GM DON'T KNOW WHAT THEY ARE TALKING ABOUT. Besides that, the rest of us aren't morons and many of us have experience as GM tech's. You may be able to get buy with running the lower octane but it doesn't mean it's good. You know kinda like cheating on your wife. You may get buy with it for a while but eventually it'll catch up. No offense intended, just a metaphor

drptop70ss

LOL I am not calling anyone a moron, and my car runs fine on 87. Will I run 87 in a 10:1 454 with iron heads? No, but it works fine in my LT1. Since nobody else runs 87 I guess the question doesnt apply here, I will just block the EGR and see how it runs on 89 first.

rasputin

ever seen an intake after 80K miles of having EGR installed? black carbon build up sucks so I deleted it.

SNOTGREEN

I run 87 in my '93, but run 93 in the '95.

So far no worries, no pinging, and that's after 8k miles (been driving the car every day). I bought it in June btw, and no problems of any kind, blows no smoke etc I say delete it, I did, just waiting for my egr delete plugs to come in from R&D.

pizzi-man

Hey DRPTOP, I have an lt1 in my 66 and ues the cheapest gas I can find with no problems. You can send your computer to someone and have all th [edit] removed that you don't need and have it programed for the 87 with no problems. As a daily driver upgrade your transmission to a newer one with OD.