qwiketz

Hi guys. I recently installed vortech ysi with Greg's bracket. While it's a very nice piece, the tensioner doesn't put out as much tension as I'm used to from my other kits. I don't know if it's just this piece or if there's an upgrade that will provide more tension.

At idle, you can see the tensioner jumping around. Maybe this is a big deal; maybe it's not. All I know is that more tension generaly equals better pulley grip and with a ysi on here, I'll need all I can get. Am I over reacting? There's awesome belt wrap with this setup.

http://www.youtube.com/watch?v=BHOjHCc7B0Y

bill mcdonald

Are you getting any slip when you are playing with it?

If you are concerned I suppose you could rig up a threaded stopper. I think there were many threads on this years ago.

basically set it up, and then set tension on a bolt or nut that would lock the idler arm into a position.

Brand-X

are you loosing boost or are you dusting belts? If not, I think your setup looks very nice. Actually, I would probably go about 1/2" shorter belt as you are about maxed out on your tensioner travel--under wot, the belt will stretch.

qwiketz

time will tell if I'm getting belt slip. I haven't had a chance to get on it yet because the car isn't tuned and doesn't have big enough injectors yet. The belt wrap is nice but I'm used to the stock vortech tensioner which is very stiff or the mustang ones that you tighten the belt and then bolt down. I'll dig through the archives.

When I bought the kit, i was told to expect belt slip so it's not like the slip is unexpected.

LPDesRoche

I wouldn't do anything until you actually see if there is a problem or not. You can also try different size idlers to improve belt wrap, Greg will work with you on this to get it right. The 8 rib setup will have more grip with a loose belt than a 6 rib with a tight one. So you may be fine, who knows.

bill mcdonald

dug this up real quick
http://forums.corvetteforum.com/show...ight=tensioner

qwiketz

thanks for the pics. I'll be working on the car tonight so I'll try to come up with some ideas to kick around.

ztrips

Are you sure your tensioner is good? I would wait and see if you have belt slip before you get too worried...

qwiketz

Hi guys. I have an update on this thing. Over the last month or so I've been swamped at work and I had to replace my rack and pinion twice due to a defective replacement unit.

I took the car for a ride a couple weeks ago and the boost maxed at 10psi with the 3.0/ 7.35" combo. I believe that this is about 5-8lbs short of where it should be.

Today I took a tool (torque wrench) in the garage to see how much tension there was. To make the tensioner budge, it only took about 5 lb foot of torque. With the tensioner applied more (by using a shorter belt) I would see 10lb foot, twice as much. With it almost maxed out I saw 15lbs. I think I'll try a shorter belt and eventually, I'll fabricate something like in the picture above.

I'll probably do this once I buy a wideband so that I can watch for the car leaning out as I add boost (my old setup was about 10 psi).

qwiketz

This spring loaded tensioner is driving me crazy. I put a shorter belt on it today. I still didn't see more boost. The belt tension with it tight increased from 5lb ft to 10 lb ft, but the auto tensioner still bounces around like crazy. Each time it bounces, the tension drops down to less than 5lb ft (or less). I need to fabricate a manual tensioner.

lead foot 85 vet

Be careful.....I went with the shorter belt and lost the bearings in my alternator.........the accessories won't like the pre load

CRV3TT3

Same thing happened to me when i added the blower with a tight belt. (all my friends had belt slip gremlins, and i didnt want them! lol)

qwiketz

I have a 92 with a separate belt for the blower from the accessories. I ran a separate belt with a manual tensioner on my mustang pretty tight and didn't have any issues. I'm thinking I may try that if I can't figure out away to at least add a little more tension reliably and control the oscillation. I'll try to post a video of the new belt setup.

qwiketz

Update- the car is currently getting tuned. We're only seeing about 7-8lbs of boost currently. The belt is definately slipping; there's about 5lbs by 3500 rpm. In addition, one time boost spiked and went from 5-6 psi to 14 psi. This only happened once from a stab in first gear.

I went to a shorter belt and the tensioner is almost maxed out the other way meaning I can barely get the belt on the thing now. At this point, I'm seriously considering replacing the tensioner with something more heavy duty or adding a spring mechanism similar to the picture that Bill posted. Wrap is great, but tension is lousy. Belts are brand new gates micro v.

Previously I mentioned that the tensioner starts to give at 5lbs of boost. With the shorter belt, that number is up to 10lb ft on the torque wrench, but is still very far from where it should be.

My logic for a heavier tensioner is that this one was originally used for 6 rib. An 8 rib belt by design requires more tension if I'm not mistaken.

Either way, with a heavier tensioner or a threaded bolt connected to a spring, how much tension should I look for? What is a good operating range for this measurement. I know that racers put 150 lb ft on theirs for maximum belt traction(and it works to 29-30 psi with this blower). While this isn't realistic for street use due to bearing issues and lack of a crank to blower pulley brace, what is realistic? How much pressure are you guys seeing?

On another note, I think that I may have to install a brace from the blower to the header bolt or maybe an intake manifold bolt to keep the blower bracket assembly from flexing. I know that there is some degree of flex present even after tightening down all the bolts. Maybe my fab shop can handle both issues (the brace and the modification of the bracket for a threaded spring tensioner). I have seen and maybe can modify a mustang bracket to fit.

Baldturbofreak

Cog drive goodies from ATI+ jones racing products or wait a few months and go twin gt35R's.
Makes more room for the AWD

qwiketz

Well, if I could get rid of the opti spark I could run a 10 or 12 rib setup or a 50mm cog. This blower will pull the ribs off a 35mm cog. I thought of going that route prior to upgrading to my current 8 rib setup.

Baldturbofreak

Ya know what fellas,
A 2000+ nissa sentra with the 2.0 SR20 has just about the same Dizzy as our optispark(identical reluctor-wise). Just less poles on the high tension side. I wonder if we could take the electronics from one and put it in a small cap HEI?

option 2
Pillowblocks on the front framerail and a small driveshaft off the crank.
This will allow any pully you can stick behind the radiator and take the blower right off the motor mounting it to the farme of the car instead.
option 3
Take a few crazypills and run motorcycle chain like Tonydee does,lol (sorry tony,couldnt resist) As long as the pullysizes don't make the chain take to tight a turn it will holdup.

AKS Racing

Russ,
How about some pics of the bracket and the belt wrap (drive and driven shive). You say that you have sufficient wrap, but I wonder if you really do.

I have run the modified ATI bracket (320°+ wrap on the driven shive) on many different combos, and been able to get 15+ psi (provided the heads aren't too big), and see significantly more boost on mine even after removing the cog drive.

What is the step up ratio on your Vortech? What diameter is the driven (blower) shive?

Lets see some pics.
Aaron

qwiketz

Aaron,

The crank drive is 7.35". The blower pulley is 2.75". Step up ratio is 3.45. In the first post there is a video of the tensioner oscillating at idle.

On a different note, Reichard racing makes a similar tensioner, in a manually adjustable tension style but for a whopping $300. It is intended for the mustang cobra but might work with this setup.

lead foot 85 vet

I just checked the tension on mine..........11 lbs.........stock tentioner on my 85 with a 12 psi pulley.....procharger p600b......about 300 degress of wrap......no slip.


p.s. thats with a loose, long belt....11 lbs just to get it to move......with a shorter belt and preloaded tenioner it is more.