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slick-svt
10-09-2005, 10:53 PM
I would like to add an upper pulley I've seen 2.80's and 2.70's, the 2.80 is supposed to add about 3lbs. of boost so would the 2.70 add about 6lbs? Another thing is will it hurt the boost gauge (factory one) if you're making like 14 to 16lbs. of boost and it pegs it? I have a predator with a pulley tune on it, this is where I need to put it on a dyno and have A/F adjusted under WOT and maybe some timing retarded.
Highlander540
10-09-2005, 11:02 PM
Most uppers seem to add about 1 1/2 pounds of boost.

Why not add a 4 pound lower pulley insted? less belt slip.

Never heard of hurting the factory boost gauge, they are not very accurate anyway.

A dyno tune sounds like a good plan.
slick-svt
10-09-2005, 11:11 PM
Thats probably what I'll do I can get the whole kit belt and all (maybe a 6lb????)
Highlander540
10-09-2005, 11:23 PM
A 6 pounder would give more power......but only with a very good tune. Do not use a 6 poiunder with the Pred pulley tune. Remember Winter is coming. I would stay with a 4 pounder for the street, maybe get a 6 pounder with race gas for some strip racing.
BLACKSUNSHINE
10-09-2005, 11:27 PM
A 6 pounder would give more power......but only with a very good tune. Do not use a 6 poiunder with the Pred pulley tune. Remember Winter is coming. I would stay with a 4 pounder for the street, maybe get a 6 pounder with race gas for some strip racing.

I have a 6# w/ predator, 68K miles no problems. 125 mph in cool air and no boom....yet.
Highlander540
10-09-2005, 11:30 PM
I have a 6# w/ predator, 68K miles no problems. 125 mph in cool air and no boom....yet.

Thats great, I am just saying IMO I would not suggest it.
slick-svt
10-09-2005, 11:39 PM
Does running a pulley kill top end alot?
Highlander540
10-09-2005, 11:54 PM
No, should give more power everywhere. Only thing that would kill upper rpm power pulley related would be excessive heat.
BC Lightning
10-10-2005, 12:29 PM
Just watch the top end in the cool weather. I blew a motor running 140+ in cool weather. I had only a 4# pulley too.

34,000 miles with a 6# lower and 2.80" upper pulley, and no problems, I also have a bigger heat exchanger and long tubes to dispense the heat better and run less boost.
Highlander540
10-10-2005, 03:27 PM
Just watch the top end in the cool weather. I blew a motor running 140+ in cool weather. I had only a 4# pulley too.

34,000 miles with a 6# lower and 2.80" upper pulley, and no problems, I also have a bigger heat exchanger and long tubes to dispense the heat better and run less boost.

Thats some good advice.:beer: