anorman91

I have a 03 coupe
BBK CAI with aluminum spacer
BBK 80mm throttle body
BBK intake manifold
BBK shorty headers
cats no muffler, took titanium z06 off
ls7 clutch and other maintenance

i took it to be dynoed in seattle and only got 310 whp and 330 torque.
any ideas why? i know it needs to be tuned pretty badly but i was expecting at least 385/400
thanks!

RonSSNova

None of those parts are going to significantly increase power.
Needs a cam to shine.

Ron

anorman91

do you have any suggestions ? stage two? i also have 120k miles on the car

Supercharged111

For starters, you can throw all those BBK bits in the trash and stop referring to mods in stages. LS7 clutch is costing you power. Your power numbers are spot on.

C5 Pete

Welcome to CF.

That BBK stuff is junk, especially the intake manifold. Put the stock LS6 manifold back on it and stock throttle body. The shorty headers aren't really any better than stock manifolds.

The cats cost power, not the Z06 catback.

Get it tuned by a competent tuner.

Install a cam. The heads on these cars respond very well to valve event changes.

Hinson has a very well priced, quality header/x-pipe system. Install that, tune the car, enjoy the power.

91stroker

Those are barely stock numbers. Was it on a mustang dyno?

The BBK manifold is fine, they out perform the ls6 intake, plus the matching TB should help significantly.

Im betting its in your tune. Most intake an tune cars put down 320. 340ish I/E. You should be looking at 350-360 range. Ditch the cats and get a tune. You're leaving a lot on the table untuned.

Blow Torch

Don't expect 360rwhp with that set up
As RonSS said (and he KNOWS) those parts are not "proven" HP makers.
Shorty headers - worthless
80mm TB - wont add because you don't "need" extra air flow
BBK alum spacer - Worthless
BBK intake - not as good as Z06

Put the Z06 intake and stock TB back on.
Get a set of long tubes, remove cats (optional) and reinstall the Z06 mufflers
Install a Vararam (no dyno #s but increases performance)
If you cant go with the cam, some 1.8 rockers will help a little (5-7hp)
With a tune you should be around 330-340 rwhp with a strong running car

91stroker

310 are stock numbers on a healthy 6 speed.

Theres something very wrong. Clogged cats, tired engine, something.

We also dont know enough about the situation honestly. What dyno? If those are dynojet numbers then something is VERY wrong. Mustang dyno at elevation it might be about right. But we dont know. Or what conditions were when the run was made.

But the top end kit he bought has shown 21whp
http://www.superchevy.com/how-to/eng...ntake-upgrade/

On this set up the bbk beat the ls6 by 11whp.
http://www.hotrod.com/features/1507-...ifolds-tested/

Supercharged111

On a 550+hp motor that made power past 7000 RPM, NOT a stock LS1. Apples and orange.

91stroker

I wouldnt say apples to oranges. It still shows that it outflows the ls6.

The superchevy link also shows 21whp over the ls6 on a stockish set up paired with the TB and cai.

Those mods with shorty headers and cat back should show decent gains. But he laid down stock numbers.

But he could be at high elevation or pi$$ poor conditions. Trap speeds dont lie.

RonSSNova

Anorman91 hasn't checked back in. Hopefully our comments haven't scared him off.

Two nice upgrades to his current combo would be a 2001 up LS6 cam/lifters/springs. And a pair of freshened 243/799 heads.
The cam is goof proof, idles stock and simply works.

A third upgrade would be a nice used set of long tube headers and cats.

This would make approx 400 WHP. With a nice tune.

These cars aren't cheap to hotrod. :-)

Ron

Scotty2000SS

The 2 I highlighted in red are hurting you. Don't worry about the intake and throttle body. Those are fine. Maybe get them ported for a nice little gain.

Are you running heavier aftermarket wheels and or brakes? Post the dyno sheet if you have it.

Breze84

Intake and TB will gain nothing if anything. Basically comparable to the Stock LS6 intake & TB... IMO the LS6 intake is more beneficial do to the fact that the BBK intake retains heat and raises IAT temps which pulls timing... The shorty headers as well are really worthless for HP and would see marginal gains with a Cam over stock manifolds. What I would do personally is sell the the BBK stuff or leave at minimum the intake and TB and throw on a set of LT's, Also I would get rid of the BBK Inake and Spacer, The Spacer alone is costing you airflow because it disrupts air velocity. I have seen guys lose several whp with a spacer. Get a Vararam CAI and some LT's with a retune and your car will run A LOT stronger. Dont chase dyno numbers because thats all they are, NUMBERS!!!!

anorman91

I appreciate all the input everyone has been really helpful, I'm military and just got back to the states not to long ago.. i got the car re-tuned and its making 368 to the wheels and 385 tq.. everything has been fine until yesterday , its thrown a p0300 code, i replaced plugs (NGK iridium) msd wires and new fuel filter and the problem is still consistent ....
driving me crazy, from ATL but now live in washington state , this problem happened after a heavy rain and a drive after sitting a month . . thanks for all of your help!

black00ta

This

Breze84

Run it at the track now and see what it traps, That will tell you real HP

Roddy13

Wow, no I don't think so. 368hp with those mods.. not possible. You were on a very generous dyno, a poorly calibrated dyno or had a dyno operator who was an amateur.

BBK CAI with aluminum spacer
BBK 80mm throttle body
BBK intake manifold
-------------------------------------- Maybe 7-10hp for the above
BBK shorty headers
cats no muffler
------------------------------------ Maybe 8-10 hp

Most C5's stock with the 6 speed make 295-305hp. With your mods above and a very good tune you could expect to see 315-325hp tops.