I have an overdrive pulley but no extra boost??

bryant10

Registered User
hey guys what's up? This might sound like the dumbest question you ever heard, but I am a college kid I am good at asking those. Anyway, I have a 92 supercoupe with custom cold air, exhaust, 4.30 gears, and a 10% pulley. The problem I am having is that I get max boost as soon as I give it gas, but I am still only getting like 11 or 12 pounds. Any ideas why I am not getting any more. I kept thinking it is the blowoff it starts getting loud at like 4500. And drops my boost a little more than I would like sometimes.
 
bryant10 said:
I kept thinking it is the blowoff it starts getting loud at like 4500. And drops my boost a little more than I would like sometimes.
What do you mean by blowoff? Do you mean a blowoff valve like a turbo car? Our cars dont have blowoff valves. It could be boost coming out of the vacum lines on the intake plenum. Put some hose clamps at the ends of the lines and it could fix your problem.

Shane
 
I've got an aod with a shift kit and an 1800 stall. And you are correct that there isn't a blow off valve but there is a divertor valve. It opens that little butterfly and is the same thing as a blow off it just diverts it internally to keep the air volume calculations from the maf correct. At least that is how I understand it
 
and yes I use lots and lots of gas unfortunantly, but it isn't as bad as I had originally thought. like 2500 rpm for a good 65
I was scared at first but it works out pretty well rarely ever see the highway, except to go to the track and run some 18's
:confused:
 
Sounds like you are enjoying some supercharger belt slippage. Run to the parts store and pick up a Gates K080390 or other brand in equivelant length and toss it on your car, should eliminate your problems.

Paul
 
That is not a blow-off valve, nor does it work similar to such a device on a turbo car. That is a bypass valve that is either open or closed. When the engine is under vacuum the valve is used to reroute output from the supercharger back into itself to prevent cavitation of the supercharger. This dramatically reduces the drag on the engine when not under boost as well as smooths out the power impulses from the SC. It should never

Make sure all the IC tubes are bolted up tight. And it is likely that you are having belt slippage. Look for black dust around the snout pulley from the belt getting burnt up.
 
how are you using 4:30's and getting 65 at 2500 rpms, do you have the right speedo gear? My 95 ran almost that with 3:31's???
 
actually I can't find a speedo gear that is right I went to Ford and told them I went from 3.27 to 4.30 and asked for a enw one and they said they didn't know how to tell what I needed. I guess they are typical ford employees. So to figure out my speed I used a friend one night, and gaged all speeds with his 03 mustang. They are Ford Motorsports gears from summit. I can hit the speed limiter at 3700 rpm which is a lot more than 65.
 
Some ford houses are staffed by dip-shitz. it is long distance probablly (if not, lets get together ;-)), but you could call Texoma Ford and ask for Eric. He's only 20 ish, but if anyone ever installs gears, or has a phone question about which speedo gear to use, they pass it on to Eric(who has a speedo gear chart right by his desk). Call (903)465-5671 and ask for Eric (or Lee if he's not there)!

Ken
 
You can't get a speedo gear for an AOD with 4.30 gears. The nearest is one for 4.10 gears (23 tooth) and with that one the teeth are so small the gear will wear out within 2 months.

You will need an electronic speedo calibrator, and the only one that worked on our cars is no longer made. At least I couldn't find it when I had 4.10 gears. I'm back to 3.73s with a 21 tooth gear and that seems to be working well.

David

PS: Sounds like your belt is slipping, and your not going to see full boost anyway until you get up to around 5300 rpms.
 
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