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I've got an iron LS3 with stock 853 heads and 0.045 gaskets. Pistons are out of the hole some so it's definitely over 11.1:1 static. I'm using a comp cams 54-424-11 with stock gears and ls2 chain. The listed Ivc for that cam is 41@0.050 and 68@0.006. I have no issue at all with detonation at any load or rpm point on 91-93 octane and 22 degrees all in. I really lug mine with the 2.73 gears too and it's fine, I'm going try and work my way down to 87 and see how bad it effects milage
Yeah, a lot of people are surprised by it. With a heavy (nearly 4000 pounds with me in it) 6 speed manual Monaro that is now only used on the street, I want a different type of cam to most on here with lighter, high stall auto cars that like to race and add all the trimmings. I had a thread on here late last year where I was going to get a custom cam motion cam to replace the current cam motion 218/226 as I am not happy with it but that is now off the table, I have decided to go a TSP off the shelf cam. I am looking at their 212/218 or 216/220 cams. Tiny and not even worth it in a 5.7 is what the majority tell me (and always have) but I am comfortable with my choice. Here are the events for my old cam (first), the two TSP cams (2 and 3) and my current cam at 4. In the image below you can see a big difference with the events between 1 and 4. I have been paying particular attention to IVC and EVO for the power delivery I am chasing. However unlike most people I want to keep the cam quiet with little lope. If that is not a requirement then you can choose a different (bigger) cam to achieve the same results. A lot of its in the tuning too but its a variable I am happy to remove.
I think I'll keep my mild cam then and retard it -2, if it pings due to the high compression I'll just loosen off the spark plugs a little until I get it tuned properly.
This way some of the compression will blow out past the spark plug threads !!! 😉
Yes that's right although I'll still be running more comp than I originally intended and my old tune was for stock comp on 91 aki e10 fuel with similar 219/224 BTR cam. I was hoping to use that tune to run my new engine in properly for 500 miles before having it thrashed on the dyno. But it could be a bit risky with old tune as its not for new cam or new engine despite being close. I have 3 bottles of octane booster just in case.
This is what the Summit calculator tells me that I'll end up with if I retard 2 from my current possition to get IVC at 40 for safer 11.0:1 comp. The minus 4 means ATDC .
What I'd like is it to peak at 6000 and carry flat to 6400 that's my perfect scenario, I realise it may not.
I typed my numbers straight off the degree wheel into the calculator.
02-27-2020, 03:53 PM
