Safe boost level.....

cjthor · Post by **cjthor** » April 14th, 2007, 5:07 pm

Ok...
cometic head gasket
ARP studs
weisco pistons
b6t rods
Whats safe for boost? im hitting 18psi and wonder how much more can my motor take without going kaboom? garrett gt2871R turbo fyi.

JWMotorsports · Post by **JWMotorsports** » April 14th, 2007, 6:55 pm

Which B6T rods are you running? The GTX rods (which have a larger base at the bottom of the beam and a little larger rib up and over the wrist pin area...they may even be a stronger matterial, but that I don't know) I'd estimate they'll hold up to around 400WHP for a good while as they were used in the 88-89 323 GTX's to win the class N World Ralley championship both years in a row...I believe they were running around 320HP with the ralley cars. The other rods are the same as the Miata rods...aka small B6 rods. If these are what you have then HP & torque are your limitations and I don't recommend over 300-350WHP on those if you want the motor to last for a long time. I ran the small rods in my test engine and it took 26psi on a GT3076R for about 10,000miles before metal fatigue snapped the #1 rod just below the wrist pin. We had the timing very conservative and estimated around 400+WHP on average with that engine.

As for the other components...they will hold up just fine, your turbo might give up before those parts do...unless your detinating. My test engine only had ARP head studs and a Fel-Pro MLS head gasket...the rest was stock.

TREVO123 · Post by **TREVO123** » April 14th, 2007, 9:09 pm

Probly safe to run 20psi, anymore then that ur gonna need some better internals i think. of a really good tune.

osargeant · Post by **osargeant** » April 15th, 2007, 3:55 am

I agree with Trevo123 here, I wouldnt risk running more than 20psi on the motor on a continous basis.

First of all I am not sure how you will manage you drive the car on the street at 20psi without being real careful, mine is really a handfull at 12psi on the VJ-11 turbo which seems to be always on boost.

Great going with the dyno result of 300whp, nice numbers for a 1600cc motor. You just need to get some 1/4mile numbers now.

RS_OBD'oh_2 · Post by **RS_OBD'oh_2** » April 15th, 2007, 11:30 pm

The pistons and rods should be rated for 30psi... But I would not go over 400hp. I'm not too sure what turbo/cfpm they were originally rated for.

osargeant · Post by **osargeant** » April 15th, 2007, 11:53 pm

I dont recall B6T rods being rated for 30psi, I think you might be confusing them with the GTR rods from GTR BPT engine.

RS_OBD'oh_2 · Post by **RS_OBD'oh_2** » April 16th, 2007, 7:28 pm

My bad.... I was thinking of the GTR rods.