LS Build: In Progress
05-02-2019 | 06:53 PM
#271
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Joined: Jan 2016
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From: San Tan Valley AZ
One thing about the stock, car engines, is they have an engine management system. My 6.4L hemi is 10.9:1 stock. It also is very sensitive to octane, air temperature, fuel mixture etc. Could see some short term knock retard just from going from one gas stations 93 to another brand. It runs great, thanks to a modern engine management system that as many failsafes working nonstop to prevent detonation. Basically, they run it on the edge from the factory , and "tuning" doesnt do a whole lot for them. The engines run near peak performance thanks to all those sensors.
That beIng said, prob not where id want to be with a carburetor setup and basic ignition setup. I don't think 11:1 compression is "mild" by any means, for a pump gas boat engine. Id say its a bit closer to borderline , and a bad tank of gas away from knocking itself to death. LS or not, detonation doesnt care what you name the engine. Id keep a close on that tune . What kind of egts were you seeing from cyl to cyl?
That beIng said, prob not where id want to be with a carburetor setup and basic ignition setup. I don't think 11:1 compression is "mild" by any means, for a pump gas boat engine. Id say its a bit closer to borderline , and a bad tank of gas away from knocking itself to death. LS or not, detonation doesnt care what you name the engine. Id keep a close on that tune . What kind of egts were you seeing from cyl to cyl?
Last edited by mggdoors; 05-02-2019 at 06:58 PM.
05-02-2019 | 06:55 PM
#272
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Joined: Jan 2016
Posts: 493
Likes: 17
From: San Tan Valley AZ
One thing about the stock, car engines, is they have an engine management system. My 6.4L hemi is 10.9:1 stock. It also is very sensitive to octane, air temperature, fuel mixture etc. Could see some short term knock retard just from going from one gas stations 93 to another brand. It runs great, thanks to a modern engine management system that as many failsafes working nonstop to prevent detonation. Basically, they run it on the edge from the factory , and "tuning" doesnt do a whole lot for them. The engines run near peak performance thanks to all those sensors.
That beIng said, prob not where id want to be with a carburetor setup and basic ignition setup. I don't think 11:1 compression is "mild" by any means, for a pump gas boat engine. Id say its a bit closer to borderline , and a bad tank of gas away from knocking itself to death. LS or not, detonation doesnt care what you name the engine. Id keep a close on that tune . What kind of egts were you seeing from cyl to cyl?
That beIng said, prob not where id want to be with a carburetor setup and basic ignition setup. I don't think 11:1 compression is "mild" by any means, for a pump gas boat engine. Id say its a bit closer to borderline , and a bad tank of gas away from knocking itself to death. LS or not, detonation doesnt care what you name the engine. Id keep a close on that tune . What kind of egts were you seeing from cyl to cyl?
05-02-2019 | 06:58 PM
#273
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Joined: Oct 2007
Posts: 8,439
Likes: 94
From: yorkville,il
Good guess. I would say that I am pretty much at the limit of stock ls3 heads on a 4.030 bore as far as hp goes, maybe a few more if I wasnt running marine application. Valve shrouding is hurting me so the only thing left to do is porting. I am done playing around with them for the summer and am going boating. At the end of the season, mid november lol, gotta love Arizona, I will be doing cnc heads and roller rockers. Results will be posted again.
05-03-2019 | 10:39 AM
#275
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From: San Tan Valley AZ
Here is a 468 blower motor on the same dyno just for comparison sake. You can decide if it is greedy or not. I believe he said this was 731 cam 
Last edited by mggdoors; 05-03-2019 at 10:42 AM.
05-03-2019 | 11:17 AM
#277
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Posts: 14,106
Likes: 3,692
From: On A Dirt Floor
05-03-2019 | 11:20 AM
#278
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Joined: Jul 2004
Posts: 11,332
Likes: 73
From: chicago
