07vbluestang

i recently installed kooks 1 3/4" LT and 3" catted h pipe. i was running frpp tune and then i got a dyno tune. i actually lost 14 h.p. and torque and my dyno sheet says i lost alot of low end. i have the 3.375 pulley and want to replace it with a smaller pulley but i am not sure which size. i want to go with the reichard racing 3.1 or 3.2. also i am running a tune with 18 deg. timing and i have another with 19 deg. timing in my tuner. please give me your input on which set-up would be the best!.

will i have to get another dyno tune going with a smalley pulley?

if i take out the cats will that affect my dyno tune?

hammeron

is your whipple generation1 or gen2

onederful100

where is your hp/tq now?
if you just want to gain back the 14 hp, i would just leave it as is until you get a built short block then go crazy.
especially if its sitting around 450 or less hp now on the stock short block, i would leave it.

07vbluestang

my s/c is gen 2! my frpp tune was 469 rwhp and 442 torque. i should of left it alone but i already had the headers and h pipe bought and the dyno tune paid for. now i am at 455 rwhp and 439 torque. but i lost alot of low end torque cause of the headers and h pipe.

hammeron

i would leave well enough alone, unless you have a burning desire
to spend lots of money for piddly power increases.

it's very hard to beat the whipple tune in terms of safety and overall
driveability.

SpartaPerformance

I don't know why you lost power, the only reason would be a poor dyno tune, it could also be the H pipe. People don't realize that "H" is not as efficient as an "X". For an "H" to work properly it needs to be custom made for the application for the proper cross flow to occur and increase power. Many people by "H" for sounds and end up losing power.

07vbluestang

i was making 469 rwhp with 11 lbs. of boost. now i am at 455rwhp with 9.5 lbs. of boost! even the throttle response is not there like it was with the frpp tune.
can i go with a 3.2 pulley to get some back with my dyno tune.

loots06

If you really want the numbers get A different TB that should help otherwise leave it alone.

07vbluestang

what TB am i looking for?

onederful100

most aftermarket TB will require a retune.
L&M TB claims to not need a retune, but i have no 1st hand info about that.

i think your HP loss and boost loss is due to the large diameter LT's and large h pipe.
but your engine is now more efficient than it was with the stock exhaust, which is a good thing.
hp and boost are only measurements, boost is a measurement of pressure and really means little in this particular situation.
with LT's you will lose boost, i lost 2 psi with my exhaust.
i am at 449 rwhp/ 419 tq @ 7 psi with a 3.5 pulley on a gen 1 whipple.
being i have the stock block, i like where i'm at right now, nice and safe so it seems.
safer than if i were at 499 rwhp and 11 psi.
i will take an ounce of prevention, instead of a pound of cure any day.
if i were to race every weekend, it may be a different story, but for a DD or a weekend warrior not so much track time, you are just fine where you are.
do you have a dyno graph?