prestonztt

Alright, I have a 99 Mustang GT and have a quick question.

I have the on3 turbo kit with the MP T70 upgrade. I also have Probe H-Beams, Diamond 19cc dish pistons (which makes the compression with PI heads 9.1), MLS Headgasket, ARP Head Studs, and stock crank.

What do you think would be the most boost I could run on this setup with a good tune and pump gas? And race gas?

jvog

Its really hard to say how much "boost" rods and pistons can take, its more about hp numbers than anything else. Hopefully you have piston rings that are designed for boost though, otherwise you'll be gettin a good bit of blow-by. It depends what brand pistons and rods and what quality, but I'd say forged rods and pistons are good for 700hp+

lizzyfan

Yep, but remember when you get over 500rwhp it's gonna be fuel system restrictions

vanquish

Also isn't the stock crank limited by around 600 hp?

lizzyfan

It is, so they say but no reports of broken ones above 600rwhp. Like to know how many folks have taken a stock crank to and above that level!
I sure was skeered! Opted for
the Cobra crank!

sstang

+1 not worth the risk of ruining your investments in other parts. I would stay around the 500-550 range. Turbos dont need as much boost either, maybe 12-14 psi will get you around there I would think?

Mustang_NTriangle

What are your rods and pistons rated for? All points mentioned above are valid especially fuel system beyond 500 RWHP.

vanquish

I have the stock crank but fuel setups start to get really expensive at 500+ hp anyways so I'll probably be satisfied around there.

Chris98Gt

Did you build your shortblock or have one assembled? Make sure the rings are gapped for a boosted application. I saw thread a while back on theturboforums about a forged shortblock letting go on the dyno because the rings were gapped too tight, closer to factory specs than a turbo spec'd gap. The more boost you plan on running the more gap you'll want according to the guys over there too.

prestonztt

Well my mods for the fuel system are pretty good. I have a walbro going into -6 line feeding 62# injectors. I'll actually be installing a second walbro this week. Yes I put the short block together. I would have to see what I gapped the rings because I can't think of it off hand. I wrote all the engine specs down.

All in all I feel totally fine with my rod and piston combo, but the crank is something that's just worrying me a little. I'm almost tempted to through a cobra crank in there and just call it a day.