max boost on a 4 bolt head.
Bringing back an old thread. 454 LS Iron Dart Block. 9:4:1 F2 Procharger. 4 bolt head with a 28.5 psi pulley. Boost went above 30psi but the graphs show 22 psi when the coolant pressure spiked. Essentially the heads lifted at 22psi with cometic head gaskets 4.205 gaskets.053 thick.
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overboosting too early in the rpms and excess cyl pressure too early can bend up some pretty nice parts
a little bigger turbo and lag that ramps upstairs and really comes on can be a good way to go
I have the ttix kit and it actually hits a bit hard with the tiny turbos
a little bigger turbo and lag that ramps upstairs and really comes on can be a good way to go
I have the ttix kit and it actually hits a bit hard with the tiny turbos
The freeze plug blew out the back of the block behind the flywheel too lol. ****!!! I just wanted to post this video since it was done last week to show what lifting the heads looks like and pressure needed on CNC Ported GM LS3 4 Bolt Heads.
Where did you steam clean the floor at?
Haha a. Steam cleaned. Yea...I felt bad. KP Racing. I'm having to pull the motor to get to the rear freeze plug that blew out behind the flywheel too. Tapping then bitches this time and sealing for good. If it lifts the head this next time hopefully it'll blow out a radiator hose lol and not a freeze plug.
And that guy who says he's running 35psi on a 4 bolt head is either running 8:4:1 compression or he's Oring-ed his block and head or he's a liar. 22psi and **** got ugly real quick on a brand new engine. I just showed that. What computer are you running. What kind of car. The Corvettes factory PCM can only read 22 psi of map,after that the Tuner can add up to 30psi through hp tuners into the computer. Past that point an aftermarket computer is required.
And that guy who says he's running 35psi on a 4 bolt head is either running 8:4:1 compression or he's Oring-ed his block and head or he's a liar. 22psi and **** got ugly real quick on a brand new engine. I just showed that. What computer are you running. What kind of car. The Corvettes factory PCM can only read 22 psi of map,after that the Tuner can add up to 30psi through hp tuners into the computer. Past that point an aftermarket computer is required.
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Verdad Gallardo Steam Clean What did your AFR do when that boost pressure zoomed up? Looked like some bad stuff happened quick and in a hurry. That even looked like a freeze plug rolling across the floor.
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Haha a. Steam cleaned. Yea...I felt bad. KP Racing. I'm having to pull the motor to get to the rear freeze plug that blew out behind the flywheel too. Tapping then bitches this time and sealing for good. If it lifts the head this next time hopefully it'll blow out a radiator hose lol and not a freeze plug.
And that guy who says he's running 35psi on a 4 bolt head is either running 8:4:1 compression or he's Oring-ed his block and head or he's a liar. 22psi and **** got ugly real quick on a brand new engine. I just showed that. What computer are you running. What kind of car. The Corvettes factory PCM can only read 22 psi of map,after that the Tuner can add up to 30psi through hp tuners into the computer. Past that point an aftermarket computer is required.
And that guy who says he's running 35psi on a 4 bolt head is either running 8:4:1 compression or he's Oring-ed his block and head or he's a liar. 22psi and **** got ugly real quick on a brand new engine. I just showed that. What computer are you running. What kind of car. The Corvettes factory PCM can only read 22 psi of map,after that the Tuner can add up to 30psi through hp tuners into the computer. Past that point an aftermarket computer is required.
At the risk of mudding the water and possibly making myself sound like a moron, why is everyone concerned about boost number? Making power is not about boost, but about flow capacity. Boost is a measure of resistance and past a certain point will only generate heat, not power.
Having the right components like good flowing heads, proper cam, etc...will allow you to make more power at lower boost levels, which should ultimately be the goal for anyone.
Andrew
Having the right components like good flowing heads, proper cam, etc...will allow you to make more power at lower boost levels, which should ultimately be the goal for anyone.
Andrew
Boost and Flow Andrew,
I agree with you. I was just surprised the 454 cid set up popped like that. Maybe those heads were too restrictive for that much flow. That's why I was wanting more information on the situation.
Denmah has shown us enough crazy good tuned up runs on here to make me curious about what is causing issues.
I agree with you. I was just surprised the 454 cid set up popped like that. Maybe those heads were too restrictive for that much flow. That's why I was wanting more information on the situation.
Denmah has shown us enough crazy good tuned up runs on here to make me curious about what is causing issues.
Yes that was a freeze plugs rolling across the floor. 5.3 with 40psi...weirder **** has happend.
I was unlucky I guess...but I was pushing too much boost. I'm gonna drop it down to 20psi with 6 bolt heads. Or 18psi with 4 bolt.
I was unlucky I guess...but I was pushing too much boost. I'm gonna drop it down to 20psi with 6 bolt heads. Or 18psi with 4 bolt.
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yup, boost is just stacked up air with no where to go 
on my old turbo buick, I upgraded the heads and turbo at the same time
lowered the boost from 23 to 18 psi, ZERO detonation, and the car picked up from 11.2 to 10.8
cfm and cyl pressure tell the tale, but are harder to discuss and measure
on my old turbo buick, I upgraded the heads and turbo at the same time
lowered the boost from 23 to 18 psi, ZERO detonation, and the car picked up from 11.2 to 10.8
cfm and cyl pressure tell the tale, but are harder to discuss and measure
