Safe Boost Level???

[gibbs_000]

I have an 85 t type that is stock except for flowmaster exhaust. What is a safe level to turn the boost up to??Its only for the street no 1/4 racing yet. Also what kind of HP increases would i be looking at for increasing the boost??

Aaron

 

[Buick From Hell]

depends...with a stock chip, low altitude and 92 octane, it should handle 15psi to start with. I'm at 4200' altitude, have a chip with more timing, and we have no better than 91 octane gas around here. When I finally got my boost gauge, I found I was only running 8psi! So, I cranked in the rod 4 turns, which gave me 12, and BIG difference! So I went two more turns and hit 14psi, still okay...

Right after that, the wife needed to go someplace, so I went for 16psi. About 10 minutes into our ride, I had some room for WOT for a few seconds. I watched the gauge, and the second it hit 16 I got a single, extremely loud <WOCK>...

It sounded like a cannonball hit the block! And the boost gauge dropped to 10psi before I could back off the throttle! (wastegate solenoid doing it's job!)

I backed it off to about 15, and it's been there ever since. I can't hear it knock, but I know that it is, simply because I can feel the car surge when the timing is being backed off by the ECM, and the boost will back off to 14...

Anyway, I think 15psi is a good starting point!

 

[gibbs_000]

Im pretty much sea level here and The best gas i can get is 94 octane. What kind of HP increase would there be if i ran around 12 psi??

 

[cool 84]

12psi? It should be running that stock. I don't know the actual hp difference but if you go from below 12 to 15psi it will make a huge difference. On 94 octane and a stock chip you should be able to run 17psi but I would keep it at 15 until you get a scan tool.

 

[Lee Thompson]

?

The general rule is--- 1 pound of boost-----10 HP

 

[TurboRegal84]

Dont even thinking about moving that waste-gate before you put in a Walbro Fuel pump.

I got my knock gauge on stock pump, and when I was only running 8psi the gauge was in the yellow, and sometimes red...that is 5-10* of retard.

Put in a Fuel pump, and a hot-wire kit..and THEN go playing with the boost. It would really suck to blow a motor instead of buying a Pump, and Hot-wire kit for $160.

 

[gibbs_000]

Ya i was planning on putting in a fuel pump because ive heard alot of bad things about it.

 

[gibbs_000]

WHat is a Hot wire kit and what does i do????

 

[cool 84]

A hotwire is basically a thicker wire going straight to the fuel pump. It usually feeds right off the back of the altenator and will deliver full voltage to the pump instead of ~11v like the stock wiring does. I made my own for about $10.

 

[dave84gn]

Made your own eh? Sounds cool.

Yea a hot wire kit (well mine at least) will come with a wire, with a 30amp fuse in series. and a relay that activates when your old fuel pump relay activates (if I understand things properly).

But it's basically just a long wire

Dave

 

[cool 84]

I ran a thick wire off the alternator back to the fuel pump. I used a Bosch relay and triggered it with the fuel pump jumper wire so it comes on whenever the stock relay is energized. It cost around $8.