Built 306w/ on3 turbo. What boost level is needed for mid 400hp?

Musclemustang65

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I have a 95 with a 306 (Stock block,crank,& rods) with new forged (9.6:1) pistons, AFR 185 heads, Comp 274 HR cam, Edelbrock RPM intake, 75mm TB, 76mm bullet MAF (Kit comes with a different MAF), 38lb injectors.....etc.

The guy with the bullet MAF & injectors claimed he made over 500hp with his turbo setup with those 2 items so im assuming mid 400 is attainable with them for me.

So im trading for an ON3 turbo kit with the stock crappy ON3 70mm turbo, bov, &wastegate. All which will be upgraded in time, but as of right now I need to figure out what boost level is needed for mid 400rwhp. So far that seems like the sweet spot for a stock block and good tune. I was thinking 5-6 but Ive heard low numbers with the base turbo....

Any help with boost levels or pointers?
 

castine917

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Boost is relative to restriction. There is not a set number. Install, adjust tune, go from there.
 

ryclef331

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What he said. Put the kit on and turn it up until you obtain your goals.
 

daves94vert

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I would guess, if you don't have a dyno:take it to the track and run a low 11 or so.
 

330CubeGt

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Like everyone has already said, but if i had to throw a number out there for you to think about i would say 8-12 psi.
 

1bad9d5

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just like Cube said... 8 probably looking 400-420... but 10,11 will get you 450-465 to the wheels..
 

Musclemustang65

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I know its not a specific science but im just trying to figure out what I need to run and not over do it as the whole new engine build will be tuned the same time the turbo kit will be on. So there are a ton of tuning variables im worried about. Ive just heard mid 400 is the safe spot so that's what Im aiming for. Maybe a lil less being an auto.
 

Musclemustang65

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I also don't want to push a lot of boost with the stock turbo/bov/wastegate setup as ive heard those are the weak ON3 links. Atleast until I can afford to upgrade them.
 

hondarocks61

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6# waste gate spring with a manual controller, turn up as needed. With your combo I honestly couldn't see you needing to run more than 8# to get to your goal, based on the other setups I'v seen.
 

ryclef331

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I also don't want to push a lot of boost with the stock turbo/bov/wastegate setup as ive heard those are the weak ON3 links. Atleast until I can afford to upgrade them.

Minus the hot and coldside tubing....you just said the ENTIRE KIT was weak point. If you don't trust it, don't run it IMO however...

Weak faulty BOV....big deal. As long as it doesn't come apart and the motor doesn't end up eating parts, the worst it will do is leak boost or bark the turbo a couple times but you'll know when it does that. cheap to replace. probably be plenty at the low levels you're running.

Junk Turbo...9/10 times is the seals that take a dump, and you end up with oil in the intake. Big deal. You knew it was junk, bound to happen, no harm to the motor. You aren't going to explode one with the low volume of air your motor will need. Easily replaced....costly but easy.

Wastegate...here is where I wouldn't skimp. If something goes wrong here, you COULD potentially over boost the motor and it will grenade. Tial, JGS, Precision...can't go wrong with any of them but I wouldn't trust something that I couldn't directly contact the manufacturer OF that component and i highly doubt anything from On3 has a "Made in USA" stamp on it.

Thats how I would approach this. I would run a chinese ebay gt45 turbo is a SECOND just for fun but I would make sure my controlling components are up to par.
 

Musclemustang65

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That pretty much sums it up. I plan on buying a Tial wastegate before tuning and should only run lower boost levels with the HCI I have.
 

2002BLGT

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10-11 psi will make over 500 easy and anything over 450 you are asking for trouble if you have not atleast put ARP rod bolts and other hardware in the engine , last one I tuned made 514 with only 12 degrees of timing at 11psi and spit a rod cap off 3 weeks later due to still having stock rod bolts
 

330CubeGt

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They make a tial knock off that's real nice and when I had mine side by side with a real tial.Both 50mm you couldn't tell the difference and even the internals were the same.My buddy has been running one at 15psi for a few years with no probs.
 

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