I have them installed on my '00 FRC and am getting no hp gains from it.

Before installing them, I had the LS6 intake, Vortex Ram Air kit, and the Borla XR-1 muffler cat-back setup. With this setup my car made 345.8 RWHP and 347.6 rwtq.

I bought the Belanger longtubes, installed them, and had a custom off-road h-pipe made to fit them to the Borla XR-1 cat-back. After a day or so, I re-dyno'd and came out with 346.2 and 347.2 rwtq.

2 weeks later, I dyno'd again to see if the computer just needed some time to re-learn. Again, I dyno'd 346.4 and 343.1 rwtq. At this point, Im pretty upset as I have about $1600 tied up in these headers, including installation and misc crap. Im also about 120 bucks into dyno time.

So, I get on the phone with the vendor and discuss the situation with him. He has no clue. Speedworks has no clue, nor does Fastech.

The vendor made a couple of comments about the dyno's there and the possibility that the readings could be off. So, I head over to Fastech and got it dyno'd again.

It dyno'd @ 346.4 and 354 rwtq @ fastech just one day later. It looks like its picked up some torque and .2 rwhp. Not sure why the difference, but its close enough.

Sean threw the GM Tech 2 on it, cleared the long term fuel trims and redyno'd. This time, it picked up to 354 rwhp and 357.4 rwtq.

Both Sean and Speedworks agreed that the computer would probably relearn its fuel curve and drop back down.

Its been several weeks since and I decided to take it to speedworks again and dyno with open headers. With open headers, it dyno'd @ 357.2 rwhp and 358.9 rwtq.

It looks like its not made any gains and that the headers are in fact the peice holding back power.

The vendor keeps throwing out that my car was already making abnormally high horsepower with the 3 mods. I belive it should make at least another 12 to 17 rwhp with those headers.

I recently added a "Shaner S2" ported throttlebody. It shouldnt have added more than 2 rwhp and 2 rwtq. There was a significant gain throughout the band, which the latest dyno done with open headers shows.

Has anyone seen this before? I should have gained something from just losing the cats with this setup, let alone just the headers. Im quite disappointed and working with the vendor to decide what to do. I have to call him tomorrow and discuss the lastest dyno I got this weekend.

I wonder if its just the Belangers and they need better flowing heads to get any noticable power gains. I can't find anything else wrong. The car doesnt have any bent pushrods and the h-pipe has no restrictions to it. I can't figure it out.

I'd hate to get rid of the headers tho if they will show a gain on a set of ported heads as compared to say, the TPIS headers.

What to do?

Thanks,
Shane

 

Evil,

346rwhp with the mods you had before the Belangers sounds very high. As a point of comparison, my car pulled 331rwhp with the mods in my sig starting from 345hp at the flywheel.

I assume your car is also a M6. I would think that 346rwhp is about right after the Belanger installation. A mystery... :confused:

Herb


[Modified by 4DCYKEY, 1:29 AM 6/18/2002]

 

A couple of uneducated thoughts:

You would probably be better off with an X-pipe over an H-pipe, better pulse balancing and less turbulence.

It does seem that your car is making abnormally high numbers already.

It sounds like you gained a significant amount with the ported TB - maybe your intake is now the restriction, see if you can swap to a clean filter and dyno again. Also, an LS6 intake would probably help quite a bit.

What does the actual graph look like? I'd Autotap or Ease scan and see what your timing and fuel is doing.

Edit: The LS6 I believe has D-shaped exhaust ports - could you have gotten a set of Belangers with D-flanges, and put them on your round-exhaust port LS1? That'd be a massive restriction right where it counts most. I'm not sure on any of this though, take it with many grains of salt.

Sam


[Modified by Sam Lin, 11:31 PM 6/17/2002]

 

I know someone that installed TPIS Headers and only picked up 6 rwhp! Go figure, why! I picked up 14 with the TTS.

 

Evil,

I'd recommend all 8 days of the week going with the LG Motorsports longtubes, and after much research, I had my anticipations met, and exceeded with the RWTQ numbers below. Unfortunately, I was unable to get a before-header dyno, but rest assured, there was an unbelievable jump in SOTP feel. I probably gained about 15 RWHP, and probably 25 RWTQ according to Lou. I got average HP numbers, but exceptionally high TQ numbers. I wish I could have run the dyno during cooler temps....

I would recommend exploiting any money-back guarantee that was available if you are not happy and go with the LG's. :jester

 

I agree. . :yesnod:

 

You pre-header RWHP figure does seem a bit high to me as well. Also, did you get an Air/Fuel reading while at Wide Open Throttle on any of your dyno runs? Perhaps the headers adversely effected your A/F at WOT and are robbing some power. If so, a MAF Translator may quickly fix that up.

Also, I have heard that Tri-Y headers such as the Belangers do not always give the best peak power gains.

 

forget the peak gains for a moment and concentrate on the whole curve....did you pick up any hp/tq across the entire operating range? If you did, then I'd be pleased. :D

 

I'm with MattG, what was your AFR on the dyno? This is absolutely essential to gaining power!

 

Some here are saying your pre-header numbers are unordinarly high. But I think your pre header gains with the vortex are actually right on for a Z06, if not a few pobies too low.

 

Guys, he said he installed this on his 00 FRC. Not his Z06.

Anyways, his before numbers were wrong, and his after numbers are right. I'm 95% sure thats what happened. An LS1 with headers and no cam/heads pretty much tops out between 350 and 360rwhp every time. His after numbers look spot on for where they should be.

 

Ah, I was just looking at his sig. Yeah, then I would definatly say his numbers were waaaaay off for just the mods listed before the headers.


[Modified by kewlbrz, 12:32 PM 6/18/2002]

 

Well surprise! As an engine builder, I can assure you that everyone wants a "Magic Bullet," i.e. one replacement part (preferrably cheap and easy) that will make HUGE differences in performance. We call this the Hot Rod Magazine syndrome!

As we modify an engine, eliminating breathing and fueling shortcomings it becomes harder and harder to do additional changes of ANY kind that make significant differences (apart from major compression-ratio increases or oxygenating in one way or another via nitrous, super-, or turbo-charging). This is called the "law of diminishing returns" and it applies to virtually all phenomena, not just engine power production. However, if one is building race engines, even a meager power gain may make the difference between winning and losing and enough of them added together might actually be noticable in this regard on a regular basis.

What you have learned with your headers is most likely that the ones you replaced were not much of a bottleneck on YOUR engine, as it is currently configured. Consider yourself lucky; many who spring for an engine mod, buying into the marketing hype, find that one change in and of itself actually HURTS performance! This happens more than you might think. We get someone who wants our "best" cam but we cannot convince him that without the approriate heads, fueling, exhaust, etc., he isn't going to break records at B'ville (as we do), set records at the drag-strip, or whatever. Significant performance gains depend on what one starts with and how well integrated the changes are with each other, among many factors. All the best. :yesnod:

 

I need to update my sig. I sold the Z06 a long time ago.

Sam - I already have the LS6 intake.

For comparison, a friend of mine has a '99 coupe and he has done the Vortex Ram Air and the Borla XR-1 mufflers and is pushing 331 RWHP @ the same dyno. Add in the LS6 intake for about 15 to 17 rwhp and he's right there where I was with exactly the same mods.

Now, unless the stock heads are just flowing as much as they possibly can and thats the restriction, there is something wrong with the headers or the combination. Im not sure which.

As far as the A/F ratio's, here they are:

Mods: Bone stock:
13:1 till 4000 rpm, then it starts to decend to 12:1 @ 4500 rpms and thru out the rest of the run.

Mods: LS6 intake, Vortex Ram Air, Borla XR-1 exhaust
13:1 thru the whole run, slightly getting to 13.5:1 for about 500 rpm between 3500 rpm and 4000 rpm.

Mods: Same as above but added Belanger long tubes and off-road h-pipe (no cats)
13.2:1 until 4500 rpm, then dropping to 12:2 @ 5000 rpm and thru out the rest of the run.

Mods: Same as above but with open headers, no h-pipe, no mufflers
Could not get accurate A/F readings due to the open headers, so we stopped trying.

I don't think that the car is making abnormally high horsepower. The only thing I can think of is that the stock LS1 heads are the restriction @ this point and that I could possibly benefit from ported heads.

BTW, I am running nitrous. My only 1/4 run with the headers before the throttle body was 11.54@126 MPH @ Ennis. Race weight was @ 3405 #s with me in the car and I was running 104 octane race gas.

Using one of the calcs, that breaks down to theoritical HP of 536 rwhp to push that much weight that fast.

Any other ideas?



[Modified by Mr. Evil, 12:45 PM 6/18/2002]

 

No offense, but no way will an LS6 intake make 15-17 rwhp on stock LS1 heads. 5 rwhp if your lucky.


Who did the dyno originally before the belangers?. Was it SAE corrected? Was it dynoed only that once before the headers?



[Modified by kewlbrz, 1:00 PM 6/18/2002]

 

kewlbrz - I have dyno'd @ SpeedWorks in Lewisville every time. I have gone to Fastech one to dyno only to appease the vendor to make sure that Speedworks dyno was not reading high. Even then, the day I dyno'd @ fastech for comparison was after I dyno'd the day before @ SpeedWorks.

It was SAE corrected. I had dyno'd it 2 times before the headers.
Once when I got the car and it was bone stock, and second, after installing the LS6 intake, the Borla XR-1, and the Vortex Ram Air, all done on the same weekend and dyno'd a few days afterwards. I don't really know what each of the mods individually since I installed them at the same time.

For the record, the dyno graph with the headers and h-pipe looks identical to the previous graph before the headers. Again, my only thought is that the stock heads are restricting the power @ this point. Perhaps this is why the Z06 makes the extra power with similar mods? The better air flow?

 

its quite baffelling. Alls I can say is that with your current rearwheel numbers. Your right where you should be with your mods.

Might try running autotap while on the dyno, and see if there is something going on like a lot of knock retard or something.

 

Regardless of what the dyno says, did you pick up a consistant mph or two through the traps? Can you feel any more power when you drive it?

I agree that your power is right where it should be for what mods you have done to your car. I really think perhaps your pre-header dyno was the one that was off.

 

I really don't think my pre-header dyno was off. If it was, it would have been off on several peoples cars since I had it done @ a Dyno Day event.

No one had any abnormally high dyno numbers that day and some made less than what they thought they were going to do.

I noticed no power SOTP after the install, only it sounded hella better. This would signal to me that the dyno was on the money showing no gain.

When I installed my Shaner TB, I noticed the difference in it immediately and especially after a couple of days. This signifies that the dyno graph showing a gain thru the band was correct due to the TB. This also matches what TamuZ06 gained with his Shaner TB.

 

Your current power number is PLENTY high for your mods--basically a bolt-on car (unless I missed something) . You have powe equivalent to a 2002 Z06 WITHOUT GOING INTO THE MOTOR. That is very strong. Your headers are fine.

If you want more power, do cam and heads.

No offense intended, but what AVANTI said: too many people think you can bolt-400rwhp. This just does not happen: air intakes do not produce 30rwhp and neither do headers.

Enjoy your strong ride!