Belt slippage???

[GrabberblueS197]

Im asking this question for a friend if mine, We recently added a 2.6 pulley to my friends 2011 GT500 and also added an idler pulley. Car feels strong but is going into limp mode (I think) when hes hits full boost which is at about 12lbs right now. The car seems like it just shuts off, drops boost then comes back up. It seems like belt slippage but we did some research and everyone seems to be saying that a smaller belt is not necessary. So what do u guys think should we go for a smaller belt or is there some other issue going on. The car has a jlt cai, ngk plugs, pulley, idler and a john lund box tune. Any ideas of what it could be? thanks in advance

 

[dysan]

I'm just throwing this out there but was the car tuned for the smaller pulley? I could see the car's computer forcing itself into limp mode if it detects too much engine load or too high a MAF count above what's in the tune.

 

[DraggnRoush]

Going to a smaller pulley is notorious for causing belt slippage - which is exactly what it sounds like from your description. It's better to get the greater boost by increasing the size of the crank pulley than by decreasing the size of the blower pulley... you may have success by trying a better belt tensioner... like the Reichart Racing manual tensioner - do a search, good luck!

 

[GrabberblueS197]

I'm just throwing this out there but was the car tuned for the smaller pulley? I could see the car's computer forcing itself into limp mode if it detects too much engine load or too high a MAF count above what's in the tune.

Yea the tune is for the smaller pulley its a box tune from Lethal performance (john lund) designed specifically for the cai, and pulley combo. Ive heard john lund knows his tuning well so I dont think it was a tuning issue the car just gives out and then comes back on I was just wondering if anyone actualy had a smiliar combo and went ahead with a smaller belt. Thanks though the tune was my first guess too.

 

[GrabberblueS197]

Going to a smaller pulley is notorious for causing belt slippage - which is exactly what it sounds like from your description. It's better to get the greater boost by increasing the size of the crank pulley than by decreasing the size of the blower pulley... you may have success by trying a better belt tensioner... like the Reichart Racing manual tensioner - do a search, good luck!

Actualy it might be a belt tensioner issue spoke with lethal performance and they said the tensioner is adjustable I guess well try that route first. We never adjusted once we put it on so maybe there was alot of play on the belt cause like I said the cars just completly drops boost and gives out then comes right back on. Thanks

 

[GrabberblueS197]

Update

So I thought i'd post an update just in case anyone else had a similar issue and needed help with it. It looks like it was the belt tensioner, apparently it has three adjustments to it that u can use to tighten up the belt a little more so we used that last bolt on the tensioner and no more slippage. Heres before and after pics u can see the difference in the space from the idler and the pulley the extra slack on the belt was causing the car to drop boost completly. Redemption killl vid coming on Wednesday...

 

[DraggnRoush]

Ah-ha... belt tension! WHO wudda thunk it? LOL!

 

[dysan]

Sooo much tension on this site .

Good to hear you figured out the problem.

 

[GrabberblueS197]

Yea lethal performance was pretty good at getting back to us. Easy fix. Took us no more than 5 mins to take the idler off and adjust it.

 

[GrabberblueS197]

Sooo much tension on this site .

Good to hear you figured out the problem.

Stay tuned for the kill thread tomorrow against a Novi 2200 05 Gt! The guy got a win cause of the boost issue last time so it should get good!