was expecting more than 350hp...
this man knows his ish and has proven it time and time again. People these days are so quick to put down log manifolds without any real experience. People have been using log manifolds for YEARS, and some manifolds even worse than a simple log (i.e. modified factory manifolds) and have made plenty of power. The simple fact is the car has an issue somewhere. It should make more power with what it has on it now. Find the issue, fix it... then upgrade
We need a like button on HT. who's with me ?
this man knows his ish and has proven it time and time again. People these days are so quick to put down log manifolds without any real experience. People have been using log manifolds for YEARS, and some manifolds even worse than a simple log (i.e. modified factory manifolds) and have made plenty of power. The simple fact is the car has an issue somewhere. It should make more power with what it has on it now. Find the issue, fix it... then upgrade
But he certainly doesn't need to change camshafts for this.
however, something like a tubular log, or a rev hard with a turbo that big id be worried about reversion and excessive backpressure. id be more worried with larger cams but in this case the gsr cams are making that situation not as bad as it could be but still im sure its a contributing factor.
its not the cams, id still say boost leak is the largest contributing factor.
Leak is the biggest factor..type of manifold I'd minimal at best. You'd only suspect it with an EGT reading, really.
Look to the manifold dead last. But here, it's not the case with a large leak like this sounds..
Leak fix first, the see about parts replacement
Look to the manifold dead last. But here, it's not the case with a large leak like this sounds..
Leak fix first, the see about parts replacement
Going to check.for boost leak in the tomorrow a.m. took it out for a run today and think i lost boost almost completely. A/f ratio went so lean it wouldnt read part of the time too... have to rig up some sort of cap with a nipple and pressurize it...think i saw one made out of pvc maybe... thanks again everyone... didnt expect to get this much help... def appreciated.
so having a log manifold that is not efficient enough for your build can cause higher egt?
I have recently installed a oil catch can with breathers to decrease my crank case pressure. After installing though, I noticed it doesn't have quite as much pull when accelerating and a little bit into the drive, I noticed my air fuel ratio was much higher (lean I think) than usual, sometimes not even registering on my gauge... Ive tried to do some reading on the subject but not a lot of information particular to my situation. I also checked for leaks, found a couple very small ones, just enough to whistle and make some bubbles, will fix today. Any thoughts on the new issue?
I suggest you stop driving like brian o connor and have someone who knows what they are actually doing take over from here
If you dont know what is lean or rich then that motor isnt going to last very long
If you dont know what is lean or rich then that motor isnt going to last very long
Ive done a leak test on the charge pipe/intake but not the engine itself. I have stopped driving it, until i find out the most current issue, but other than that the tuner said it was safe to drive
that, and because the leak is causing the car to get closer into vacuum his management and gauge are not reading as rich as it needs to be. Its a direct correlation.
That's like having someone panic about their gauge reading 15.2AFR for a split second after letting off of the accelerator suddenly and coasting while driving on the highway. Its "lean" because he's not running any fuel to the engine while coasting to an exit ramp. Doesn't mean its so lean that it'll detonate.
He needs a boost leak tester, not just some soap and water to find "bubbles" for the leak.
That's like having someone panic about their gauge reading 15.2AFR for a split second after letting off of the accelerator suddenly and coasting while driving on the highway. Its "lean" because he's not running any fuel to the engine while coasting to an exit ramp. Doesn't mean its so lean that it'll detonate.
He needs a boost leak tester, not just some soap and water to find "bubbles" for the leak.
I used a 2.5 inch coupler with a can on one end and the other end connected to the charge pipe right off of the cold side of the turbo. I put a tire valve stem in the end of the can, hooked a pressure regulator behind an air gauge to 20 psi and pressurized the system. found a leak where a sensor is welded into the charge pipe. I used the soapy water to figure out exactly where the leak was coming from because it was hard to locate by ear.
I used a 2.5 inch coupler with a can on one end and the other end connected to the charge pipe right off of the cold side of the turbo. I put a tire valve stem in the end of the can, hooked a pressure regulator behind an air gauge to 20 psi and pressurized the system. found a leak where a sensor is welded into the charge pipe. I used the soapy water to figure out exactly where the leak was coming from because it was hard to locate by ear.
I also noticed after some time, some very fine bubbles were coming through the gasket between the throttle body and intake and the bolts securing it but seemed almost insignificant. could a leak that small be a problem?
While those leaks may not be significant, they probably skewed the results of your test, you should disconnect the charge pipe at the throttle body and have that end plugged.
When you pressurize the system with both ends sealed (coupler off turbo/throttle body) your air pressure should hold steady.
A small pinhole leak isnt going to cause this huge boost loss some seem to think your having, to lose 10+psi its going to be a substantial leak/sliced coupler
When you pressurize the system with both ends sealed (coupler off turbo/throttle body) your air pressure should hold steady.
A small pinhole leak isnt going to cause this huge boost loss some seem to think your having, to lose 10+psi its going to be a substantial leak/sliced coupler
Hell I forgot to cap off the 1/8NPT plug on the compressor housing on my GT28 once and I didn noticed it until I was trapping 10mph slower than normal and AFR's were all over the place.
Last edited by LightningTeg; Jun 10, 2015 at 08:18 AM.
Who is Mr Robot?
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It doesn't take a very large air leak to cause problems. You have to remember that injectors are open for only milliseconds at a time, it doesn't take much to throw off the entire tune.





