Okay so here's my situation. I am running fully built h22a4 with a drag turbo kit. I was running 440cc injectors and i was maxing them out at about 14psi. I now have 780's and i was wondering how far i can take pump gas. I know the shitty log manifold holds back power but i have also been informed that its not a good idea to run higher boost levels on the log style manifold. This is what my tuner said. "once you reach a certain boost level, manifold pressures become wicked wicked high, which are then increased by even more due to the backpressure from the bad flow of the log mani, which then echo's the already wicked hot exhaust heat back into the combustion chambers, causing inconsistent afr's and drastically high combustion temps, making for wildly sperratic detonation." Has anybody actually tested this out? He recommened me to not run more than 18psi before going with a tubular style manifold. Has anybody run 20+psi on a log styl manifold.. and how did it work out.

 

99.9% of the time an equal lenth manifold will make a "wicked" amount more power(sorry couldnt help it), but people have made over 600whp on drag manifolds.

your 780s are gonna cut out well under 500whp but with the manifold/turbo combination wont make that anyways...
I put down 360whp on 525cc injectors but they were over 80% duty cycle....

More research and time will help you with these questions, if your tuner cant answer stuff like this for you then its time to switch to someone else.

 

I dont plan on making huge numbers. This is a daily driver and i want to make good but reliable power. Looking for a froggy street tune. Im pretty much just looking to see how much boost i can run safely on this mani. Just looking for evidence/numbers or something to back up what he says about the mani causing problems in a higher boost setup.

 

Just for the record i do plan on getting a mini-ramhorn in the future im just strapped for cash right now. I just got over 1k in head work done. All new valves, valve job, arp headstuds, and all new gaskets.

 

He did answer these questions, the OP just didnt like the answers....If your tuner is not comfortable with it going higher, then listen to him....or find another tuner....I notice your from louisville, cincinnati isnt to far from ya, give dave blundell a call.

 

O i believe him and trust him. Its just that i had never heard of this and was wondering if its been discussed before. Or how far people have pushed the log mani.s. Just looking for a second opinion. What shop does dave blundell work for? Ive dealt with tachyon and autolab here in louisville and i dont really like either shop. This tuner im talking about is a tuner i know from the Preludepower forums hes actually up in CT.

 

I am running a p*** tubular mani with 1000cc ijectors. It does 410 at 17psi on 91 octane fully built gsr with a t3/67. I am getting ready to switch to a top mount.

 

wow i didnt realize i couldnt say that word sorry guys

 

Log manifolds are very restrictive at higher power levels...I dont know at what levels that is, Im sure it varies from setup to setup. If your tuning on a dyno, Im sure you'll see when it stops making power, and starts to lose power....Your butt dyno isnt calibrated so if you want to push it to its max then you will have to put it on a dyno. If this is a DD then I would call it a day with the manifold you got and start saving for upgrades. Im sure you can burn exhaust valves if the pressure and heat get to high inside the manifold. Pmd ya with his info.

 

If you're still running the stock turbo from your Drag kit, a log manifold isn't going to limit you that much. With the power you can realistically hope to make from that turbo, you may be losing a potential 30whp, but you will see boost faster with the log. If you have the money to blow, a new manifold and full 3" exhaust would be a good choice...if not, don't lose sleep over it.

 

Install a backpressure gauge at the turbine inlet. That should tell you more than any of the conjecture in this thread

 

I don't see the value in that type of investment for the simple goal he's looking for. If he happen to have one, I see the point, otherwise, why chase after a ghost like that?

 

Well, for one it would let him see when it's pointless to keep cranking up the boost without having to pay for dyno time. A compression fitting, some hard line, and a pressure gauge is hardly a huge investment.

 

Unlimited

 

whos your tuner? Im also in louisville, ky. I went to Billy Roberts at autolab. We got 371whp and 249 ft/lb on a log manifold with a GT3076R .82a/r hot. This was on a F20C S2000 engine but there are people in the s2k community making well over 500whp on log manifolds with no issue.

 

How much boost are you running? Just out of curiosity. As for bill.. i have dealt with him before and was not happy with anything he did.