I've used the search thread & haven't found a solid answer. What are safe boost levels on a stock block/heads? I know a lot has to do with the tune but what is the standard boost level to maintain longevity for a non-track car (weekend fun ride). 17-18# ? Can you explain why too
How much boost on stock block/heads?
- Thread starter txrunner
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Boost shouldn't necessarily be used because every car is different in terms of restrictions. For instance a whipple with a 3.5 pulley on one car may make 17 pounds and the same setup on another car may make 19.
But that said, it all depends on what gas you're using. When normal pump gas is used(93) the majority of people like that 18 area as it's fairly proven as safe. Tune has a lot to do with it, on my car I make 19lbs on my pump gas tune but have a very safe level of timing in it. Plus I'm very rarely on pump gas so that doesn't matter much.
On race gas/e85 you can up that more. I make 21lbs on e85. I wouldn't go much higher than 22lbs if using good gas as that's where people start to have head gasket/bolts problems. But there's also people out there making 24/25lbs and dont have issues.
But that said, it all depends on what gas you're using. When normal pump gas is used(93) the majority of people like that 18 area as it's fairly proven as safe. Tune has a lot to do with it, on my car I make 19lbs on my pump gas tune but have a very safe level of timing in it. Plus I'm very rarely on pump gas so that doesn't matter much.
On race gas/e85 you can up that more. I make 21lbs on e85. I wouldn't go much higher than 22lbs if using good gas as that's where people start to have head gasket/bolts problems. But there's also people out there making 24/25lbs and dont have issues.
I personally wouldn't go past 19 psi on 93 pump gas. After being on the forms and looking at many threads over the years thats what I gathered to be safe.
On my car I am running 18 psi at 19* timing pump gas 93
On my car I am running 18 psi at 19* timing pump gas 93
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22psi and E85 can run for years on a factory terminator motor.
Yea, he'll run into detonation issues with 93 octane long before approaching the mechanical limits of the engine.
Doesn't detonation have more to do with timing & A/F ratio vs. boost?
Well many variables can cause detonation. My main concern was always getting some bad 92 gas. I always test my ethanol to make sure it's around 85%. How many test there 91-93 octane fuel?
I'm making 16.8lbs max boost and 19 deg max timing. If I upped that any higher on 93 I would probably want my timing to come down a little. Even as is I run a bottle of Lucas per 12-13 gallons of 93 just as insurance against a batch of lower octane gas. Like bdubbs said - nobody test their 93oct gas. I'm not even sure there's an easy way to test it at the pump.
Detonation can be caused by all 3. Try running only 5 degrees of ignition on 40 psi running pump gas and see what happens.
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