Photochop

iTrader: (74)

I'm in the middle of rebuilding my motor and will be getting it back in the car and the turbo kit installed in the next couple months. The kit going on the car is a used HiFlo kit I bought from another forum member (turbo ls1 ss) last November. The turbo is a single PT76GTS, and the motor is a forged 347 with mahle flat tops w/ reliefs, stock 317 heads with a PRC dual spring kit (.660 lift versions), the cam is a custom grind that came with the kit - 226/223 .575/.570 on a 115 LSA.

The kit came with a TiAL 38mm Wastegate with a .9bar spring in it, and a TurboXS 11 psi BOV. I'm wanting to keep the boost/rhwp down some due to running a 'built' 4l60e...it's a rebuild and has decent parts in it, but don't think it'll hold the power the kit is capable of for any length of time. Also running a SSF TCI 3500 converter and hoping it'll hold some decent power (also running the stock rearend currently).

I'm looking to keep the power around 500-550rhwp with the current drivetrain hoping it'll hold that. What do you guys suggest for a boost level that would achieve this goal? Instead of buying a boost controller, I was going to swap the spring out for the spring that hits the 500-550 goal. What spring do you guys think I should run and is there a way to modify the BOV to work with whatever spring I swap to? Or is there another low cost option for the time being? What do you guys suggest? Thanks

Rob_Raymer

The easiest thing to do, is make the WG adjustable. You can typically get almost double the rating of the spring with a boost controller, or by manually putting pressure against the top side of the spring. So, in other words, I would probably get a 7lb spring, then tap and thread the top of the WG and install a bolt and lock nut. You'll just need to insert a steel washer that's the same diameter as the WG spring, so the bolt can press down evenly on the spring. That should give you a manual adjustment range of about 7-14lbs.

On a side note, if you want to make much more than you stated, you'll need a larger WG. That's about all a 38mm will control.

Photochop

iTrader: (74)

That works. Dunno about drillin a hole in the WG, but if you think 7 lbs of boost will hit my target HP goal thats fine. I'd heard from a supra buddy that a spring will normally boost twice its 'rating' and was thinking a .5 bar spring would suffice. If thats the case cool, the most I'll ever boost on this car until I switch computers in it will be one bar (being a 98 PCM). I was planning on adding an AEM Tru-Boost gauge later anyway and I'll just adjust it with that.

Do you think .5 bar of boost with my combo will be around 500-550 rwhp?

Sideways240sx

iTrader: (22)

Ok a couple things..

1 the tial 38 gate may be a little on the small side for running a 76 at 7-8 psi. It should be fine @ higher boost, but you may have issues.

Next, why not just get the 20-30 dollar spring from tial that does like 3-4 psi and then just use a manual boost controller. This way you can boost as low as the spring will go, and with the boost controller you can go up to what ever you want. If you get a .5 psi spring in the gate, you can never get your boost below .5 bar.

As far as the bov goes, the stock spring is fine. When they are installed/ hooked up the right way, the bov will see the change from boost to vacuum and then dump the boost left in the charge pipe to atmosphere, or recirc how ever your doing it. So the 11 psi spring in the bov is perfect for running the 7-8 psi you want.

.5 bar should put you around you 500-550 mark you want, but of coarse every combo is different.

Good luck, Chris