Ok well its making power but not much at all. Let me start from the beginning. The car is a 99 Vette had a G5X2, TPIS headers, No Cats, Stock C5 exhaust, and a LS1 intake with a MTI ram air. It made 382rwhp/355rwtq. We changed a few things up but never dynoed it. We put a LS2 Intake, LS2 Throttle body, Z06 Exhaust, and a few little things. We then put MTI Stage 2R heads, MTI Y1 Cam, Comp R Lifters, Ported Oil Pump, Double Roller timing chain, PBM Underdrive pulley Breathless 1 3/4 to 1 7/8" Headers, X-pipe with Cats, and B&B PRT Exhaust on it. We installed it all with the help of two people that do this daily The pistons were fly cutted, the cam was set on time, it was all assembled correctly. The plugs were TR6's gapped at .32 (For a dry nitrous kit). We took it to two different dynos and the most we made was 408rwhp 365rwtq on 26* degrees of timing and 13.0 a/f. It has two different people look at the tune and its dead on. The airfuel 12.8 to 13.0 across the board and the timing is 23* it made 398rwhp and 358rwtq. The graph was really jagged on motor when we sprayed it made 549.9rwhp and 550rwtq with a 11.5 to 12.0 A/F. This was done with a One Nitrous Works Nozzle, a NOS Blue Dry Nozzle (No Pill), and -4an lines everywhere. The graph was VERY smooth.

We have done a compression test and all of the cyl.'s came up like this
Driver Pass
185 180
180 159
178 185
180 190

So the break down of the mod list includes:
Stock C5 motor with 49,000 miles (Fly cutted pistons)
M6 with a Stock 3.42 Gear (Upgraded Output Shaft)
Spec Stage 3F clutch
Comp R Lifters
MTI Y1 Cam
MTI Stage 2R Heads (With all the GOOD valvetrain)
Ported Oil Pump
Rollmaster Double Roller Timing Chain
Breathless 1 3/4 to 1 7/8" Headers (No A.I.R. System)
X-Pipe (Bullets in place of Cats to see if the Cats were clogged)
B&B PRT Exhaust
LS2 Intake with LS2 Throttle Body
Stock Mass Air Descreened (We've tried a SLP 85mm Mass Air (3hp Difference)
Stock Air Bridge
30lb Injectors (FORD SVO)
MTI Ram Air
PBM 10% Underdrive Pulley
160* Thermostat
Taylor 409 Wires (Brand new)
TR6s (Gapped at .32 (Brand new))
NOS Dry Kit (No Pill)

Its not the heads because these SAME heads made 434rwhp 398rwtq with a MTI G1 cam, Hooker headers, LS6 intake, and other basic bolt ons. This was in a Camaro Z28 M6 on ET Streets.

What could be wrong with the setup? We've had everything checked. Please someone shead some light!!!!

 

Ditch the LS2 intake. They're junk! Bet you're losing 10-15rwhp compared to running the LS6 intake. If you swap to a FAST 90mm intake (since you already have the 90mm TB) and I'll be you'll pick up 30 rwhp compared to where you are now.

 

Hey man what's up? How ya been? Playing with the other toy now huh? I know this is frustrating.

Well the cats are hurting the #s for sure (20hp or so). I'd try dual cut outs if there's room or drop the X pipe for testing purposes.

Make very sure that the Comp R lifters have no more than .010 preload on them or the valves could be held open. The Comp Rs are good lifters, but you MUST have the proper preload. I was down over 20 rwhp because of this. Been there and done that. That's as far as I care to go into that nightmare.

My MTI Stage2R heads loved additional timing (30 degrees), but my smaller C1 cam with those heads I generated a lot more cranking compression.

It should be laying down some decent numbers with that set up. I hope this helps. Keep us posted on the findings.

See ya at the track!

 

ditch the LS2 intake for an LS6 or a FAST setup - running cats is also killing your #s - or running mufflers in their place

 

Well we are going to try a FAST 90 tomorrow hopefully. We removed the Cats and put 3" Dynomax Bullets. Its hard to run no Cats or anything with this exhaust because the PRTs are straight through, lol.

James we have it all set right on the Comp R Lifters, Josh explained it all to Franco (who wanted to make sure we did it right (fawking LS1!!!)). We are using the big Comp Cams Shims, so it makes it one 1/4 of a turn.

We've tried 28, 26, 23 degrees and no power differences at all.

James these are the heads of Chris E's car so ya know they are a good set. He is helping work on it, well guiding my brother. This is my brothers cars, same old Black Hardtop Vette we use to come out in.

 

Man it sounds like you guys are on top of things for sure. I hope the intake does the trick. That's about all that's left really. Keep us updated and good luck!!!

 

ttttttt

 

In addition to the intake and cats...I have a problem with the preload/rockers. Good adjustables to .008-.010" preload are the right way...anything else is a bandaid and could be causing some issues. Degrees dont me squat...inches do. But I think the intake and cats are most of your problem.

 

Looks like you have an issue with the one cylinder having only 159 vs the ave 180. Maybe a ring, or a valve is not seating correctly...

Unless I'm overlooking something here for the LS1.

 

185 180
180 159
178 185
180 190

 

Its within 15% so its healthy. This car has been beaten on a little. Now if it was 100 or 90 its time to be scared.

 

the ls2 intake only explains about 10-15rwhp of it.. i had problems on the z28 w/ Taylor wires had 2 bunk ones in the set switched to OEM wires and the misfires disappeared.

other then that can't think of anything that would rob that much power.. the injectors are upgraded but is the fuel pump? i saw a full bolt on x3 cammed ws6 go from 338rwhp to 395rwhp cause a plug wire was off

 

Ditch the LS2 intake

The cam might not like the heads

Comp r lifters might be the problem

It's one(if not all 3) of those.

 

Since you have a corvette you are losing some numbers through your drive traing compared to the z28 but i think the intake is holding you back

 

Yeah, that was the night I met you and your buddy at Fastech. Homeboy was sweating ***** about his numbers, HA HA.

Brandon

 

Really...........dont think so. I guess since the corvette has the extra flywheel, clutch and drive shaft bearings it could be robbing some HP.

Brandon

 

hahah yea that was me, scared the **** out of me, thought I had a down cylinder Sad that on 7 cylinders i was still making more power then a fully bolt on 4.6 GT Stang

 

Well? Any news after the intake swap? Keep us updated.

 

Why do you say that about the Comp R lifters?

 

Comp R lifters are designed with preload built in and require a precise preload (.02-.010). That requires the use of adjustable rockers to do it right or a very careful shimmed installation. Many people that install them think that R means race and must be a performance enhancement...WRONG. If installed as a replacement lifters beware. In most cases with smallish cams the result is just lost performance as the valves are held open at higher rpms (best case)...worst case is damaged lifters, broken retainers/keepers floating through the motor, possible P to V contact etc. Do a search in the internal section on the Comp Rs. They are very good lifters if installed properly. Just be educated prior to installation and all is well. It has been a learning experience for many and a very simple over site as externally they identical to stock so please learn from others. It's much easier on the pocket book

BTW- The Comp stock replacement lifters are the 850s and will perform with the best of those on the market today.