Max boost for compression
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#9
TECH Addict
iTrader: (34)
Yes, that was a great article but race only of course. There is no way that it could apply to a street car on running lower octane fuel. John I wouldn't go that far of wanting to sell your engine after reading that article. I think that was a joke b/c you have a stout setup in my mind. It all depends on the setup really, but many say around 9.0 and a bit higher is a happy medium.
#10
8 Second Club
iTrader: (34)
Yes, that was a great article but race only of course. There is no way that it could apply to a street car on running lower octane fuel. John I wouldn't go that far of wanting to sell your engine after reading that article. I think that was a joke b/c you have a stout setup in my mind. It all depends on the setup really, but many say around 9.0 and a bit higher is a happy medium.
#16
TECH Addict
iTrader: (17)
Where are the vids? I bet that thing is psychotic to drive!
To the original poster, it depends. Are you running on the stock non forged internals? Or is your setup forged?
Again, as mentioned before, its not a good idea to run boost on a high CR engine. You can get away with doing so by raising the octane level and or intercooling it, but you're still kind of going against what ideally you want for boost, and that is a lower CR.
Even with C16, I wouldn't run more than 10#'s of boost, especially if you are still on stock internals. The amount you're going to spend on fuel alone should make you think about just getting some forged lower CR pistons.
To the original poster, it depends. Are you running on the stock non forged internals? Or is your setup forged?
Again, as mentioned before, its not a good idea to run boost on a high CR engine. You can get away with doing so by raising the octane level and or intercooling it, but you're still kind of going against what ideally you want for boost, and that is a lower CR.
Even with C16, I wouldn't run more than 10#'s of boost, especially if you are still on stock internals. The amount you're going to spend on fuel alone should make you think about just getting some forged lower CR pistons.
#17
LS1Tech Co-Founder
iTrader: (34)
Another general observation, but the class racers tend to find the limits of various combinations, so that's why guys in like SSO have experimented with various compression levels. I'm sure a number of those guys have found out what is too much compression for their car, they can be changing engines and components quite a bit if they need to and have the funds.
#18
Who keeps spreading this BS. Compression is fine. Intercooling and Octane are you friends. Adding compression make the engine more thermally efficient,make more hp and tq and also makes the power adders work better.
This whole argument is retarded. I geuss Tim Lnych and Steve Petty should run low compression engines in SSO etc etc etc.
For that matter lets all hop on the lemming bus and go over the cliff.
This whole argument is retarded. I geuss Tim Lnych and Steve Petty should run low compression engines in SSO etc etc etc.
For that matter lets all hop on the lemming bus and go over the cliff.
Where are the vids? I bet that thing is psychotic to drive!
To the original poster, it depends. Are you running on the stock non forged internals? Or is your setup forged?
Again, as mentioned before, its not a good idea to run boost on a high CR engine. You can get away with doing so by raising the octane level and or intercooling it, but you're still kind of going against what ideally you want for boost, and that is a lower CR.
Even with C16, I wouldn't run more than 10#'s of boost, especially if you are still on stock internals. The amount you're going to spend on fuel alone should make you think about just getting some forged lower CR pistons.
To the original poster, it depends. Are you running on the stock non forged internals? Or is your setup forged?
Again, as mentioned before, its not a good idea to run boost on a high CR engine. You can get away with doing so by raising the octane level and or intercooling it, but you're still kind of going against what ideally you want for boost, and that is a lower CR.
Even with C16, I wouldn't run more than 10#'s of boost, especially if you are still on stock internals. The amount you're going to spend on fuel alone should make you think about just getting some forged lower CR pistons.
#19
8 Second Club
iTrader: (34)
IMO if you know what you are doing I wouldnt be scared of some higher compression in a race car thats intercooled running C16.
But sooner or later you will reach a point where the increased compression wont leave enough room to pack the amount of a/f in you want or the heat it creates just makes detonation impossible to control. Lot of that depends on intake port, camshaft, chamber design and exhaust efficiency as well.
Last edited by kp; 01-25-2008 at 11:11 AM.
#20
TECH Addict
iTrader: (17)
IMO if you know what you are doing I wouldnt be scared of some higher compression in a race car thats intercooled running C16.
But sooner or later you will reach a point where the increased compression wont leave enough room to pack the amount of a/f in you want or the heat it creates just makes detonation impossible to control. Lot of that depends on intake port, camshaft, chamber design and exhaust efficiency as well.
If you don't believe me and refuse to do more research, start a poll in the FI forum and just ask others in here on what the ideal CR is for a high boosted motor. I garuntee the ones with experience from doing it a while or from learning the hard way from a blown engine will tell you that if you plan on high boost, you don't want a high CR.
Simply stated, high CR + high boost = detonation. You can help your chances of staying away from detonation to a certain extent by raising the octane level, but it will only go so far to help you before detonation cannot be contained.