A story of missing horsepower

[Pekka Perkeles]

I'm writing this for trying to help a SS Camaro owner, who is very disappointed of the results of Edelbrock E-force supercharger kit in his car. I'd like to emphasize that the problem may very well be somewhere else than the kit itself. I'm actually 99% sure that this is the case.

In this case, there is a typical three-party setup. The owner, the builder and the tuner. I'm the tuner and as I said, I'm doing this to help the owner. There are no hard feelings between parties and we all would like to find out what is the problem. I also want to write this in a story format.

Now, the car originally had a L99 engine and automatic transmission. It was dyno tested here in Finland and the output from the crank was 410 hp. I don't know the exact numbers, was it really 409 or 411, but anyway very close what the factory is claiming.

Several months later the same car but with a new owner were at the same dyno. Without any modifications or changes, the car put down something between 360...370 hp from the crank. So for some reason, the power was clearly lower than previous time. There were no error codes or anything visible.

The owner wanted 600 hp from the crank, so Edelbrock E-force supercharger kit was ordered and installed by a professional who has his own company and has been on the U.S. car repairing business for last 20 years. The tune was uploaded from the handheld provided by the Edelbrock kit, i.e. at that time I wasn't part of the project at all.

After the installation the owner took the car to a same dyno again, and the output from the crank was something like 448 hp at 6300 rpm's. Obviously the owner was not happy at all.

Couple of days later I got a call and the owner asked if I could tune his car. I asked what is the problem. He said that when he was at the dyno, the guy who owns the dyno said that the engine runs too rich at WOT and if I could make it leaner, which I agreed to do.

Two weeks later we met at the dyno I typically use. I wanted to have a baseline run to see how rich the fueling is. It wasn't rich. It was almost perfect. But the power output was 448 hp from the crank at 6300 rpm's. Peak boost was about 7 psi.

At that time I finally heard the story about missing horsepower already with a stock engine. I recommended to find out the actual problem before doing anything. The owner insisted me to start tuning. It was almost hopeless, but I managed to squeeze 455 hp at 6000 rpm's from the crank. This with 11.74 AFR and 15 degrees of advance ("realized" advance, not just the values in the high octane table). IAT was 138 fahrenheit at 6000 rpm's and both MAF airflow and Dynamic airflow around 470 g/s.

I said to the owner that I can't tune your car so that it produces 600 from the crank. You have to find out first what is the problem. The dyno operator said maybe the cam is one teeth off. The owner then thought that maybe it is the problem indeed.

Next week the owner contacted the builder. I don't know what they discussed, but the blower and heads were removed. LS9 camshaft was installed, as well as LS9 head gaskets. The cylinder heads were sent to a company that specializes rebuilding heads. DoD was deleted and new valley cover or I think in this case the Edelbrock plate for LS3 was installed. High-volume oil pump was also installed and new timing gears and chain. Then the engine was re-assembled.

Bad luck continued. The new "valley plate" from Edelbrock was leaking due to some problems with casting. Again the supercharger was removed and new plate was installed.

Couple of days lated the owner called me. I asked if the builder found the problem. The owner told me that the company which checked the cylinder heads said that the engine had been running hot. And that was it.

I was pretty sure that this was a bad news. Anyway, the owner wanted me to tune the new combination. I did and was able to squeeze 470 hp from the crank...

Obviously the owner was not happy. He said to me that now the car has been mechanically fixed, the problem must be in the tune. I said that there's no magic switch or functionality I can enable to create horsepower. Fueling is right and the advance is very near the knock limit.

Then I asked if he has cats in his car. He said that yes, there are Magnaflow cats, pipes and silencers, but the headers are stock L99 headers. I said the cats may be clogged. He didn't believe me, since the cats were practically brand new. I said let's measure backpressure. And there was more backpressure than boost. Something aroud 8 psi.

So we emptied cats and were able to get 520 hp from the crank. The owner was hoping over 600, maybe 650, since it now had a LS9 cam in it. He said it's the tune. I said let's try again with stock Edelbrock tune, and it gave bit less than 520 hp from the crank. Exactly what I was expecting, since my tune was very close to the Edelbrock tune at WOT.

Then we tried with TR6 plugs instead of stock ones, but no difference.

With LS9 cam now instead of original L99 cam, we lost torque low down, which is self-evident. The owner drove the car at street and noticed immediately the same thing. And was not happy at all.

All in all, already in stock configuration, the car had about 50 hp less than it should. Now with supercharger and LS9 cam, it's missing maybe double that, i.e. 100 hp (from the crank). All this leads me to believe that the original problem has never been found. Also, the Magnaflow cats were installed after the car had been dynoed 360 hp from the crank, i.e. when the car was really in a stock configuration.

Couple of days later the owner called me and asked if I could call the builder, Mike. I agreed to do so and called him. We had a good, long discussion. He explained that he did not see anything unusual in the cylinders and that he degreed the cam based on Lingenfelter instructions. And that he really doesn't know what the problem might be. I proposed a leakdown test and he said it's up to the owner to decide.

I then called the owner and said that you should do the leakdown test. I also promised to ask help from international forums. And here I am now.

Any ideas?

[yotaman96]

I'd say a leak down test should have been done long ago. How are you getting crank horsepower numbers? Are you just estimating based on rwhp? Every dyno graph I have seen with the LS9 cam and blower shows a loss of low end power, but a gain of about 30 rwhp up top. Not a great cam in my opinion.

[dan0617]

What is the power at the wheels through the auto? Maybe the crank hp is being miscalculated. 520 crank would be about 440 or 450 RWHP I'd guess. Not that far off for it being choked so bad......

If it is running the stock air box, stock exhaust manifolds and 7 psi, you might not be down on power as far as you think. Put on LT headers, a good air intake, bring the boost back up to about 8 psi after the changes, make sure the fuel system and injectors are keeping up and you will have found A BOATLOAD of power.

[Pekka Perkeles]

The owner of the car has been a bit hesitant to do a leakdown test. I know, I know, it would help. But anyway, there are no no signs of blowby if oil cap is removed. No burned oil, nothing from the exhaust pipes, no need to add oil. So the owner does not believe there's a problem with rings and pistons.

Here in Finland we of course measure the rwhp, but owners tend to see the crank hp as well. So in dyno, or at least on those I visit, we'll measure the loss of drivetrain and calculate the crank hp.

It would be nice if it would be just because of dyno and how the hp is measured. But I doubt..

[Pekka Perkeles]

Originally Posted by dan0617

What is the power at the wheels through the auto? Maybe the crank hp is being miscalculated. 520 crank would be about 440 or 450 RWHP I'd guess. Not that far off for it being choked so bad......

If it is running the stock air box, stock exhaust manifolds and 7 psi, you might not be down on power as far as you think. Put on LT headers, a good air intake, bring the boost back up to about 8 psi after the changes, make sure the fuel system and injectors are keeping up and you will have found A BOATLOAD of power.

With LS9 cam and cats off, the RWHP was 460 and calculated loss was 60, thus 520 from the crank.

I know/guess that the calculated loss is not inline what you probably see in U.S. dynos. But this is what I saw in the dyno.

It does indeed have stock air box and stock exhaust manifolds.

I really have no clue what should be the "right" amount of hp with this car.

Recently I heard that a manual SS Camaro with the same Edelbrock kit pushed 560 crank hp without any other modifications. So some of the difference may be related to different (?) dyno calibrations or so.

[dan0617]

I dont like dealing with crank hp mumbers, best to stick with rwhp numbers.

Is your dyno a dynojet? SAE corrected numbers?

With identical mods, it is not uncommon for an auto to dyno 40 to 50 rwhp less than a manual. They would run about the same on the track with a good driver in the manual car. Add stall converter and auto would be quicker even tho it dynos so much less.

I honestly don't think you have a problem at all. I think you will find about 30 rwhp from LT headers and about 25 rwhp from a good CAI. Just make sure you pulley down to bring the boost back up to 7 or 8 psi and retune. Make SURE the fuel system can support it. ZL1 pump and ADM FPCM and tune change to accommodate the FPCM should suffice. Make sure injectors are plenty big, big injectors will bandaid fp drop on these cars.

Are you on 93 octane? If not, going to 93 and tuning for it will offer some gains.

[H-E]

Are you running the stock pulley setup? What boost?

[3rdgen3]

Okayy...

To make the magical number of 600hp, you will NEVER get it done with the factory stock L99 exhaust manifolds.

You need to explain to the owner of this car that the factory cats and manifolds combined with the factory intake air box is a HUGE restriction on these cars.

Pick up a set of 1 7/8" long tube headers from ARH, Kooks, Dynatech, Stainless works, JBA, hell even OBX, grab a proper cold air intake (CAI Inc, ADM, etc) coupled with an AirScoop and i'll bet that you'll get that 600hp number.

[jeremywes]

My first thought was the low octane setting had been tripped but I'm sure you would have seen that in the tune

Should consider an LS3 conversion and get rid of the VVT, but I agree the stock manifolds are no good for FI and the K&N filter that comes in the kit does not fix the intake limitations. Good luck bud.

[TriGun]

The main question is how it did lose 50hp in first place when it was in stock form? (it was 410 and later it was 360).

[dan0617]

Originally Posted by TriGun

The main question is how it did lose 50hp in first place when it was in stock form? (it was 410 and later it was 360).

Hot day, different gear used, converter not locked, different calculation or correction factor, different or bad gas, these are just some of the possibilities.

Bottom line, there is no problem. Lose the stock manifolds and air box, pulley to get 8 psi, tune it on 93 watching the fuel supply closely and the AFR, oversize the injectors for safety cushion, and the owner will have more power than he is looking for.

[east TX Muscle cars]

yea you HAVE to get rid of the stock manifolds and airbox that car will pick up a TON of HP. HP loss could be as simple as he got some knock or bad gas and its on the low oct table. doesnt take much timing to be pulled on a boosted car to get hp loss.

[dekan513]

with all thats done , a ls3 conversion and head work ls9 cam. that car should get some good gains with headers and intake. but still should be above what it is. tell him to go to the track and make a few runs his mph should tell the tell.
that will let u know if its the dyno reading low. dyno might need recalibrated or could be running diff config on the dyno setup from the first run to the 360 hp run. if its not ur dyno and dont mess with it daily its hard to tell what has been done.

[epstein]

way low for an eforce ... what injectors? what fuel pump?.....