up set about massive power loss with SLP loudmouth

[Z Ya Later]

Dude, I slapped the LM on my Z back in Jan. and she runs harder now than she did before. How long has it been since the tranny was serviced? No other noises coming from the car? No surges or anything? When you say factory plugs, do you mean AC Delco plugs or the ORIGINAL AC Delco plugs she rolled out of the factory with? How is the idle? Does the motor recover from a rev properly, i.e. doesn't dip then come back up after 5-10 sec.?

[Injuneer]

The thread is getting sidetracked with the comparison to Formulaboy's car.... but the important point is that you do not lose 55HP by removing the cat and installing a Loudmouth. And its definitely not a "backpressure" issue, since backpressure isn't really an issue at all on a computer controlled fuel injection setup.

You would definitely feel a 55HP loss, and you wouldn't be breaking the tires loose in 2nd gear if it was a real loss. Did you only do one dyno pull? Do you have the sheet that we can look at? Sounds like they didn't tie it down tight enough.

As far as Formulaboy, the mods make sense.... he had cold air and a catback, along with a few others, and those are worth 30+HP. I picked up 3/10's with a Honker CAI and a Borla catback. 275rwHP isn't out of the question. A lot of the other mods aren't going to affect dyno rwHP at all:

Ram Air w/ K&N - 10-12HP, no gain from ram air on a dyno.
TransGo Shift Kit w/3 washers - 0HP
SLP~Shorty headers - not installed
LoudMouth - 10-12HP
Air Foil - 1HP
LineLocks - 0HP
1LE trans mount - 0HP
Catco Cat - not installed
Hypertech 160 & Fan Bypass - I've seen dynos with 10-15HP for the HPP WITH the 160deg t'stat. Questionable what the real gains are.
Redline Water Wet - fractionalHP
TB Bypass - 6HP
MSD~8.5mm Super Conductor's & Blaster coil - 0HP
FastToys MAF ends - 0HP
IAT Spoof - questionable, I've seen dynos that lost HP with this.
LT4KM - 0HP
BMR~Adj LCA's - 0HP
Rear sway - 0HP
Panhard rod - 0HP
HAL QA1 rear shocks - 0HP
Random Tech adj TQ arm - 0HP
Nitto NT555R's - 0HP
Covered in Zaino - 100HP (OK, I lied about that one )
NX 50 shot w/ NX goodies - not used

[Joe 1320]

Same Dyno?
Same variables?
Any other cars being dyno'd before and after that also show losses?

In any case, I prefer a different method of determining the HP.

Hit it on the last amber, and hang on.






!

[fastTa]

you say you had 275.5 hp at the rear wheels with a stock LT-1? thats like 3% drive train loss. not to doubt you but a 285 hp car with an auto (if you have that) should be right around 238~240 hp at the wheels.

Maybe on a mustang dyno. On a dynojet the majority of limited bolt-on, 4L60E, stock 10-bolt, 96-97 LT1's that I have seen usually throw down between 265-280 RWHP SAE corrected. Throw on all the bolt ons and that number will even go higher.

[azkkn]

i am leaning towards either the dyno setup being incorrect, or the tranny is slipping.

[Dave M]

i am leaning towards either the dyno setup being incorrect, or the tranny is slipping.

I would bet on the dyno being messed up or improperly used.

[azkkn]

UPDATE*****

found it, i found my missing HP!!!!! the rear calipers were out all the way and frozen solid, the inner pads were worn right down to the metal backing, and the rotors have grooves in them on that side, on the outter side, the pads are still new looking and so are the rotors.

[Kevin V 2002 SS]

Brakes grabbing would slow things down, along with the power shown on the dyno. Glad you found the problem.

[95z28]

Never mind

[Z Ya Later]

found it, i found my missing HP!!!!! the rear calipers were out all the way and frozen solid, the inner pads were worn right down to the metal backing, and the rotors have grooves in them on that side, on the outter side, the pads are still new looking and so are the rotors.

Awesome man. So, are you a fan again of the LoudMouth? lol I would notice something similar on my Jeep when the pads would get worn (the front left outer pad would stay on the rotor). Glad you found the problem. And what's up with stealin' part of my sig.? lol j/k