I am currently running a P-1SC on a 2005 Sierra Denali with a 3.7" pulley @10lbs. of boost and a killer tune by Rick at Synergy. I was running a TBTC to boost up quicker but I decided to swap back to the stock TC. I would like to drop down to a smaller pulley to build boost more quickly but I am concerned with hitting 12-13lbs at redline (my current shift point is 5800). I was wondering if I lowered my shift point to 5200-5400, would my boost come on more quickly and would the lower shift point limit the boost back to a reasonable 10lbs?

Any ideas?

Thanks, Rick

 

any other mods than what's listed in your sig?
I am still running the 4.0" pulley on a P1SC and boosting to 10+ lbs @ WOT...
The TBTC picked me up 0.5 sec in the 1320...
what's your race weight...because 13.21 @ 103 is moving for your listed mods...
got any pics?

 

Just the stuff listed + I added a magnacharger in-tank pump and 4" aluminum piping over the engine to put the air cleaner back in the stock location. I actually lost about 1/2 lb of boost when I did this. The Procharger is an eBay head unit with procharger brackets and 3" eBay tubing + a vortec bypass valve and a generic 24x12x4 FMIC. The truck is a crew cab Sierra Denali AWD 6.0l LQ9 with 4.11's, fully loaded. I would guess the wieght is around 5600-5800 wet + my 200lbs. I had a mail order tune but Rick's tune at Synergy in Fremont, CA really woke the beast up. Not a hint of ping, lots of timing and it's really responsive for a stock TC w/Centrifugal.

I never got the run a quarter mile with the TBTC. It definetely got into boost faster but I didn't like how it acted on hills (I have a couple really steep residential hills I drive everyday) so I took it right back out. I have to put it in the classified section one of these days.

I'll take some pictures and post them when it stops raining over here.

Rick

 

Run the smaller pulley and make a restrictor plate for the inlet.That will restrict the higher boost levels at high rpm.

 

Rick_Vor...
the 6.0L and the AWD probably explains your #'s...awesome
is the 13.21 w/ or w/o the TBTC?

Slowhawk...
restrictor plate...
what would that involve & how would it work?
benefits?

 

Superado...

The 13.21 @ 103 is without the TBTC.

Slowhawk...

Great idea. I little like Nascar at Daytona... I could probably use some 1/4" aluminum plate I have laying around and try a 3.1" pulley I jut picked up. I'm using 4" piping for the Air Cleaner so I could just make a disc that slips in behind the filter and start with a 2 1/2" hole and see how much that limits the boost. I guess I could even just use a smaller air filter to do the same thing.

I've been communicating with an Engineer at an Austrailian company that is working on an electronic boost controller for Centrifical superchargers that would use a solinoid and the bypass valve to limit boost. Sounds pretty promissing but it's just in the development stage.

Rick

 

You could always run a wastegate on the piping right before the TB to regulate boost levels like you would on a turbo, except it wouldn't be regulating exhaust--just charged air.

I would think that would work?

 

waste gates go on the exhaust side

 

As long as he is running speed density. If he had a maf it would cause the engine to go rich. The maf would be showing more airflow than going into tb.

 

I would try using a blow off valve to bleed off the excess boost. That way your not backing up the charger with boost.