boost falls off...belt or ball drive

[Dirk Diggler]

LONG TIME since I've visited this board! Life's been busy for me!!!

My car has sat for the past year due to work and building a new home. I took it out today and I noticed my boost would climb to 8 and then fall back to 5psi while I was at approaching the top of my rpm range. My foot was still in it. I 99% sure it's not belt slippage because I upgraded to an 8 rib system and I've never had this issue with my sn2000. I have had this problem with my VR4 so I sold it. I put a .05 shim in the charger and now it pulls up to 10psi, but it still slipps down a bit. My initial ball drive tension was 37inch/lbs. The .05 shim increased my ball drive tension to 47 inch/lbs.

I think I used to run 54 inch/lbs. Wondering what you guys think?:guess:

Thanks for the help!

[Dirk Diggler]

My last ball drive tension was about 45inch/lbs. I increased the tension to 50inch/lbs. I will bet that will do the trick as I used to run my ball drive@ 54inch/lbs.

I'll keep ya informed:freaks:

[pavement pounde]

Even my 10 rib slips if not tight enough !
Check fot slippage and be 100% sure.

[speedytang]

Also use Valvoline Type 'F' or 'FA' it has Anti-Slip additives.

[Dirk Diggler]

Thanks Aaron! Ya, I always use Valvoline type FA or Ford type F when I can find it.

I know it is the ball drive tension as I have had similar problems with my VR4. I replaced my impeller shaft and my clearances changed. Everything got much tighter inside the ball drive. I adjusted my ball dirve tension @ 44 inch/lbs and now since things have broke in, my tension was 37. I bumped it up to 48-50 inch lbs and I know that will do the trick.

I'll keep ya informed when I take it out for a spin tomorrow.:sleep::machine:

[Dirk Diggler]

Well, here's the deal. I remember my sn 2000 has always needed 46inch/lbs or more to keep from slipping. When I first rebuild my sn2K, I put everythging back together and i had 46inch/lbs stock. Craig @ Paradise said I should only have something around 22inch/lbs. My SN2K has always ran it's best @ 54 inch/lbs. I have it @ 50 and I see alomst 11psi of boost! Very consistant @ 10 psi, maybe 10.5. If I hold the rpm at my max, I can see the boost gauge just barely start to fall back. I'm right where I need to be. I should bump up my ball drive tension to 54inch/lbs, but I've got too much going on with our new home. Car...done:glasses:

[Dirk Diggler]

Ok, I increased my ball drive to 54 inch/lbs because I noticed my boost would still start to fall back @ 10psi, not all the time, but it was still slipping. From my experience, when the ball drive slips = excessvie wear. I increased my ball drvie tension to 54 inch/lbs from 50 inch/lbs and now I am consistantly getting 10.5psi! I would have thought the removal of my cats would have reduced my boost psi a .5lb or more...guess not! The thing is now, I can hardly keep my tires from spinning. But then again, That's always been an issue.

[Scribbles]

got to love the <search> button. 10.5 from a sn2000, i can live with that.

[speedytang]

Just remember you will wear things out if you don't use quality fluid and change every 3k miles.

[pavement pounde]

And with that kind of pressure a oilcooler

[Scribbles]

the good thing is my gta only gets about 600miles a year, it is truley a toy. I am just shooting for 7 right now. And i am getting a big *** cooler.

[speedytang]

I used a transmission cooler the width and height of my radiator. Never had a problem with heat even after a day of back to back drag runs or a day road racing.

[Scribbles]

That is about what i am planing, i think the cooler i am looking at is 19.5X11.

I need new pulleys two, i just want to go 10 rib and be done with it, that way i am ready for the vr4. I just want to get use to tuning what i have and be ready when i find a vr4 to upgrade.