Results 1 to 5 of 5

Thread: In need of tuning

  1. #1
    Junior SCH Member
    Join Date
    Jul 2004
    Location
    RACINE, WI
    Posts
    4

    In need of tuning

    I have a 90 5.0, it has a GT 40 intake, 70mm throttle body, 6psi powerdyne supercharger, shortie headers and flowmaster exhaust. I also have the accel 300 plus ignition systerm but the rpm retard shuts me down at 4500 so I disconnected it. I have an idle problem that roams from 800rpm all the way to around 1500 rpm. I would love to know how to fix it and a quick estimate of what horsepower should be coming out of it with these mods.

  2. #2
    Junior SCH Member
    Join Date
    Dec 2002
    Posts
    42
    Are you using a bypass valve? Without one you usually get idle problems like that.
    1988 GT
    mild Novi 1000 302
    10.9@128mph

    1988 GT convertible
    AOD, pulleys, K&N, exhaust, lowered, cowl hood....

  3. #3
    Junior SCH Member
    Join Date
    Jul 2004
    Location
    RACINE, WI
    Posts
    4
    Quote Originally Posted by exgmguy
    Are you using a bypass valve? Without one you usually get idle problems like that.
    I just looked on powerdyne's website for a bypass valve, it is 170 bucks. I really hate this company. Is there anyone else I can get one from or maybe build one myself. I got the supercharger and it was broke, the bearings were seized and the belt was chewed up. I got bearings and pressed them in. All I needed was a belt. Powerdyne wouldn't sell me one and went a step further telling me that no one else makes them and that they are patented for their superchargers only. Thank god for the internet. I got all the belts I will ever need for $2.97 each. Know anyone needing belts or bearings? I spent about 65 bucks rebuilding it. Powerdyne's estimate for doing the 30 min belt and bearing swap was over $500-plus shipping and handling. I really hate that company.

  4. #4
    SCH Moderator regattacoupe's Avatar
    Join Date
    Mar 2003
    Location
    Bucyrus oh
    Posts
    2,845
    Do a search for bypass on here and it will help you alot! Congrats for rebuilding the blower yourself!! I doubt you'll have $40 in the bypass valve when it is all said and done and it might make those internal belts last longer.
    89 Coupe with parts stacked inside of it and about 30#'s of dust on it with no end in sight. :weird:





    Although I am collecting parts for a 12.5:1 393 :D

  5. #5
    Junior SCH Member
    Join Date
    Dec 2002
    Posts
    42
    I bought one locally from a Saab dealership. Tons of factory Turbo cars use the same black plastic Bosch bypass valve. I think it might have been $40 or so, then you will just need some hose, clamps, and maybe a 90 degree elbow, all available locally.
    Does your discharge tube have provisions for a bypass?
    www.superchargersonline.com also sells the bypass valves for a lot less than $170.

    I needed to replace the small cog gear that the belt rides on. Powerdyne would not sell me one either. Right now I am having a machinist I know make me one instead. (without the holes in it so it should make a little noise now)
    1988 GT
    mild Novi 1000 302
    10.9@128mph

    1988 GT convertible
    AOD, pulleys, K&N, exhaust, lowered, cowl hood....

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •