Question about boost

Ok... earlier today I did some work on the supercoupe.

I replaced the plugs, upper & lower radiator hose, radiator, all 3 belts, and did an oil change. The old belts were pretty cracked and deteriorated.

Well.. now when I step on it I see about 9psi of boost.. and it gradually increases to about 13psi as the car gets upwards of around 4k in the RPM range. Before the maintenance... if I stepped on it from a dead stop it would peg 10psi and stay there throughout the entire acceleration range.

Is this the way it is supposed to act? I am a new SC owner so I am not sure how it is supposed to boost. I went back and checked all the vacuum lines. Also.. is there any benefit to a racing bypass valve from like TurboXS.

Sounds about right, looks like your old belt must have been slipping if it always stayed at 10lbs.

Save your money on the aftermarket bypass valve, it won't do much for our cars. Some folks have blocked off both ends of the equalizer hose that goes from the inlet plenum to the return plenum. That can help a little in terms of getting into boost faster and gaining a little bit of max boost. I had it on mine till I slapped on the 10% overdrive pulley, I don't neeb anymore boost thanks....lol.

I'll reply with a question of my own.

My car max's at 10, and barely.

If I step on it, it'll jump to about 6psi, and slowly crawl to 10. What could be causing low boost? To the best of my knowledge, my car is stock (except removed Air Silencer and K&N).

PS. The boost acted like this before silencer/K&N and is the same after.

10lbs is kind of on the low side of typical. they run anywhere from 10 to about 13 on some, stock with the K&N. Check the your charger belt is not slipping, and that you have no vacuum or boost leaks.

where is the air silencer located?

silence

air silencer is right underneath your airbox,, you have to take it off and ull see it right underneath. there are a few sites that have on how to remove it buty i dont remember them. i know someone else does though-- it's real easy--
good luck
Damon

syphon said:

I'll reply with a question of my own.

My car max's at 10, and barely.

If I step on it, it'll jump to about 6psi, and slowly crawl to 10. What could be causing low boost? To the best of my knowledge, my car is stock (except removed Air Silencer and K&N).

PS. The boost acted like this before silencer/K&N and is the same after.

Click to expand...

It could be the gauge too.

I had the same problem on my '91 and found out it was the vacuum tube going to the boost gauge was leaking. Just a thought. Brandon

Thanks.. I was kind of disappointing to not have full boost off the line, but I guess its outweighed by the fact that I build up to 13/14psi now.