Ehh individual cylinder aren't important in this case. I did 6 cylinders (the last two on the passenger side aren't accessible from the top), 6 compression strokes, throttle at WOT with the elbow off. Also, the test was done without oil in the cylinder after about an hour of cooling time from being fully warmed up. This is with a CVR protorque starter. That damn starter goes through 6 compression strokes like it's pushing a little syringe or something even with the other spark plugs in.

Anyway, I have 205-207 on all 6/8 cylinders!!! WOW!!! I had no idea it would be so consistent. I had to try a couple cylinders over again to make sure. I guess maintenance does pay off, just thought I'd share. Oh and I found that there was a good 15-20 psi gained from having the throttle at WOT incase anybody was wondering.

I wonder... do piston rings show deterioration or is it something that can just crap out on you all of a sudden like so many other things in life???

So I don't know what a stock LT1 motor with a big cam should make, but that's what mine makes and I think that's pretty decent. The cam is on a 115lsa but it's a 227/239 .560/.577 with my rockers. How does that affect the compression? Anybody else have numbers to compare w/ those or know what a stock LT1 bottom end and head should produce???

 

I did mine a few weeks ago after 40K miles (90K total) with a blower. Each cylinder was 180-185 with about 2-3 PSI leak down after 10 minutes.

 

So what do I see, when I look at this thread? I see two guys who are responsible, smart, and careful. I am curious what boost pressure you both run? These are good cylinder pressures, you must have taken care not to run poor gas, overrev, and been careful to retard timing under boost. (Also not letting your buddy drive your car helps!) Alas, we are not all this smart. When (not if)the ring lands break on your stock cast pistons, you will know it, at first, a rough idle or a miss. Break enough and it will be catastrophic! Whatever you are doing, keep doing it!
-Michael

 

Hey thanks for the kind words silver. Good to hear that stuff!!!

I'm only running 6# of boost. WOT timing is at 19* or 20* I can't remember... I run crappy 91 octane CA gas with alcohol injection to supplement it.

I usually don't rev the car past 5600, if I am really pushing it I'll take it to 6k on rare occasions but I don't like doing that unless I'm racing at the track or something. Otherwise it hauls *** regardless haha.

I am very, very careful because I know that just by having the supercharger I am on borrowed time.

Don't tell me about letting your buddy drive... I learned my lesson about that. One time I let me friend drive back when the car was close to stock. I tell him no funny stuff there's a lot of cops out and this is not your car. So what does he do??? Takes off onto the main street sideways right after I tell him not to. I'm shaking my head and little do we know, but across the street are two police cars entering the street from a freeway offramp. You can predict how that incident ended... he got a ticket with 3 or 4 violations on it.

Another time I let my old boss warm up my friend slicks (on my car) so I could practice laucnhing outside the shop. He does a rolling burnout for like 100 ft, stops, and sits there smacking my digital 6+ rev limiter for a good 20 or 30 seconds before he lets go of the brake in second gear and rides the burnout even longer. If I didn't need a job I would have socked him up right then and there... Anyway, after that, the only people that drive my car are my brother and my girlfriend and that's rarely at that. The sad part was he heated up the slicks so much that I couldn't even launch on them after that... I spent about half an hour cleaning the rubber from the back of my car cursing that stupid moron while I let the damn thing cool down. I got mine though... and we'll leave it at that haha.

 

Yep, so careful the 383 is nearly finished (sold the S trim and the car is still running really well). I'm cautiously holding out installing the T trim until it's done and in the car.

 

I'm the opposite. I just built a motor for my eclipse so I have one car that works for sure haha. Eventually I want build a 396 for the t/a but knowing my taste it's going to end up being costly...