Jimmy P

iTrader: (177)

I have been doing a few WOT runs with the new setup. 402, F1C, SDCE tensioner setup. The pulley is a 3.7". The max boost it is seeing is 16lbs, so I think the belt may be slipping. Is it normal to have some belt dust on the supercharger housing, or is that just normal wear and tear on the belt? I can wipe it off on one day, then after a couple of days it will have belt dust on it again. The belt is almost 2 years old, so I dont know if that could be the problem. I have a new belt that has been just laying around, so I may slap that on and see if it helps.
What is the rule of thumb on how tight the belt should be? You shouldn't be able to flex the belt from side to side, or something like that? Thanks

DeltaT

iTrader: (5)

Should be HARD to turn the longest unsupported length of belt 90 degrees sideways. You shoulkd barely be able to do that with one hand. I always have a little rubber dust - one of the time you want a little slip is when you shut the throttle suddenly - but much more than a fine dusting and I know it's time to tighten. Age of the belt doesn't seem to affect things much - it is more the condition of the belt and make sure it is not glazed at all on the ribbed side.

Jim

'Trust'

iTrader: (24)

Mine was slipping and hitting a wall at 10 PSI, got under the car and it looked like someone had sprayed rubberized coating on my blower and bracket, it was bad, and chunky, and this on an 8 rib. Put on a new belt, tightened the tensioner more, and it very lightly dusts after a few WOT runs on the dyno. If your belt slipped for a while before, it will be prone to slipping. No harm in trying a new belt.

Pro Stock John

iTrader: (34)

Sounds like an old belt, they do wear and stretch. I've seen some race car blower guys run the belts taut to the point where you can't twist it at all. I would think that you'd shoot for minimal flex. My old YSi could do 18 psi but at 21.5 psi the belts would slip.

stevensLS1

iTrader: (2)

Not to hijack the thread but what if your having the same problems on an N/A car? just replace the belt and tightend everything up? thanks

Jake@EPP

I belive the sdce tensioner has a SET and a 20 on it. For a bigger boost or taught belt, i usualy put it to a tad past SET.

As for belt dust, we were the king of belt dust trying to run a f1a on a stock ATI tensioner lol, 1 belt a pass! Had to clean the lower engine bay quite a bit.

Jimmy P

iTrader: (177)

We just ran it again, this time using the BS3 to verify the boost numbers. I let off it a little early, but the highest we saw was 18.2 lbs. Do you guys think that sounds about right for this setup? I did the math, and with a 3.7" blower pulley, and spinning the motor to 6,500 rpm's, the blower should be just about maxed out at 72,000 rpm's.

A little more info on the build. 402 with 8.75:1, ETP 245 heads(unmilled), EPP 232/240 blower cam, large front mount intercooler.

Jake@EPP

It SHOULD be around there as far as boost. 72k is 2k under red line.

On another note, we spun our blower to 74,100 rpm @ 6700rpm. In doing the cog drive and swapping cams (went from 236/246 114, to 232/240) it gained 3psi of boost. This netted around ~50rwhp. The larger cam was geared to a 400" motor, but they wanted to test it again. The cam shows less boost, but makes more hp

Now onto some ideas,

We used a 21mm wide cog first time around, it snapped it right around 5k or so making a pull, just too much stress. Remember, this power aint free (ive heard anywhere from 50-200hp off the nose of the crank).

There wasn't a way in hell we could get a 8rib belt to work for us, the sdce looks promising, but its still a 8rib in the end.

If you really want to see howmuch its slipping, you can get the DAE option for the bs3 and put a optical or hall counter on the SC pulley. Just an idea if your dead set on 8rib.

Pro Stock John

iTrader: (34)

Jimmy we should head to the track on a weeknite next week, bring Pete with Nile's trailer.

What I want to know is where on the North side were you able to hit 18psi, that could be a ton of power.

Jimmy P

iTrader: (177)

lol, today that was right by Petes shop. There are a couple of nice spots and the cops aren't too bad.

The car isn't 100% ready. Don Bailey is out of the country and coming back next thursday. I want to wait until he tweaks it a little more, then I will head to the track. I'm sure Pete will be down to bring his car next week.

BigRich954RR

iTrader: (1)

What crank pulley size you running? Whats you set up? what hp you putting out at lower psi and higher psi?

Jimmy P

iTrader: (177)

I am using the SDCE setup, so the crank pulley is a 7.25. I dont have any dyno numbers yet, but will in 2 weeks or so..Waiting for the tuner to come back.