High Compression
Thread Starter
Intermediate
Joined: Dec 2015
Posts: 32
Likes: 1
From: Indianapolis Indiana
High Compression
Looking this winter to do a cam swap with a brian tooley stage 3 cam on my ls2 and want to cut the heads down to give a 11.7 to 12:1 compression ratio. Has anyone done this yet? I tried to search the forum but cant find anything that relates. I'm sure trunion upgrades and pushrod length are a requirement and I want to upgrade rods and pistons and have them flycut already. I'm thinking .175 on intake and exhaust should give me plenty of piston to valve clearance. I'm looking for things I haven't taken into consideration that some forum members can inform me about. Also if someone can give me estimated power numbers I can expect. Only upgrades it currently has is vararam SC, headers, and 150 shot of N20. Like I said itll have the cam in it when the heads get cut down. any info will be helpful. Id rather have my chickens in a row before I start tearing into it.
Melting Slicks
Joined: Jun 2006
Posts: 2,500
Likes: 261
From: Miami Florida
Will not tell you what to do but your bottom end plan is solid, for street & strip car I would not increase compresion too much unless includes E85 my experience is best with reasonable compression a larger shot with a good set of heads.
Thread Starter
Intermediate
Joined: Dec 2015
Posts: 32
Likes: 1
From: Indianapolis Indiana
e85 has been a toss up for me. I really would like to do it but I'm not sure about it just due to consistency.
Safety Car
Joined: Nov 2007
Posts: 4,537
Likes: 1,405
From: Bethesda MD
If you are pulling the heads off you might consider a swap to LS3 heads since you are fly cutting the pistons. Its not too expensive, especially if you find a used set.
I haven't seen many people go above 11.5 for cars aiming for a 7000 rpm shift point. 11.2 - 11.5 seems to be commonly used for typical street cams. Brian Tooley can you some guidance on whether going above 11.5 will do much for that cam or just create tuning headaches. Alternatively, if you go to 12:1, he may suggest a custom grind to better with that compression.
I haven't seen many people go above 11.5 for cars aiming for a 7000 rpm shift point. 11.2 - 11.5 seems to be commonly used for typical street cams. Brian Tooley can you some guidance on whether going above 11.5 will do much for that cam or just create tuning headaches. Alternatively, if you go to 12:1, he may suggest a custom grind to better with that compression.
Last edited by Ragtop 99; Oct 19, 2017 at 04:37 PM.
Melting Slicks
Joined: Jun 2006
Posts: 2,500
Likes: 261
From: Miami Florida
I went e85 with my 14.1 to 1 heads and llsr cam street ls3 and just loving it I have tested e98 and e100 out of a one mile radius stations and lowest I seen is e83.
Thread Starter
Intermediate
Joined: Dec 2015
Posts: 32
Likes: 1
From: Indianapolis Indiana
If you are pulling the heads off you might consider a swap to LS3 heads since you are fly cutting the pistons. Its not too expensive, especially if you find a used set.
I haven't seen many people go above 11.5 for cars aiming for a 7000 rpm shift point. 11.2 - 11.5 seems to be commonly used for typical street cams. Brian Tooley can you some guidance on whether going above 11.5 will do much for that cam or just create tuning headaches. Alternatively, if you go to 12:1, he may suggest a custom grind to better with that compression.
I haven't seen many people go above 11.5 for cars aiming for a 7000 rpm shift point. 11.2 - 11.5 seems to be commonly used for typical street cams. Brian Tooley can you some guidance on whether going above 11.5 will do much for that cam or just create tuning headaches. Alternatively, if you go to 12:1, he may suggest a custom grind to better with that compression.
Thread Starter
Intermediate
Joined: Dec 2015
Posts: 32
Likes: 1
From: Indianapolis Indiana
Make an educated decision buy an e85 test kit and test the avaliable pumps in your area and don't go by what you read on line.
I went e85 with my 14.1 to 1 heads and llsr cam street ls3 and just loving it I have tested e98 and e100 out of a one mile radius stations and lowest I seen is e83.
I went e85 with my 14.1 to 1 heads and llsr cam street ls3 and just loving it I have tested e98 and e100 out of a one mile radius stations and lowest I seen is e83.
Safety Car
Joined: Nov 2007
Posts: 4,537
Likes: 1,405
From: Bethesda MD
If you weren't already planning to fly cut, I'd wouldn't suggest them. IIRC, it's pretty straight forward just the heads and intake manifold. There are several threads on here, some old, with guys walking through the swap.
Last edited by Ragtop 99; Oct 20, 2017 at 03:44 PM.
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