A few months ago, on the other z06 forum, there was a similar situation a man had with similar brand heads and cam. It was a Z06 and it made about 385 rwhp after the install and with tuning. He ended up having the heads re-ported and a different cam and tuning. He got to about 420rwhp after that.

 

Now that we know your mods I would have to :iagree:

I think that once you get the tuning resolved and maybe get some cutouts in order to breathe a bit better, you should be up around the 395-405 range with an M6 tranny (not as much power loss as those of us with automatics.

I hope this thread stays alive for awhile. There is some very good info in here for all of us.

Gary

 

Thanks for all of the input, guys. :chevy

There are a few questions that I have though:

1. header size - this has been back and forth - several people (e.g. MattG) have run the 1 5/8" TTS headers on ported heads without a problem :confused:

2. tuning - how much can I expect to gain if the A/F curve is in the right ballpark? I mean, if the car isn't running too rich or too lean (i.e. a flat line across) - how do you "fix" this?

3. peak power - there are plenty of posts of similar set-ups with 5-10% more power (esp. torque) - I even went the route of the extra, little things (LS6 intake, ported TB) to try and squeeze every little bit of power

4. cam size - not being a cam guru, I have to take the advice of other, more savvy folks who informed me that this was a bigger, more aggressive cam :confused:

5. KR and retarded timing - I have had problems with this for a long time now (long before the heads/cam swap) - it has been suggested that I might have an "inherently noisy motor." One thing I could try is the race gas. This would be a lot cheaper than opening the motor and searching for bad knock sensors.

Sorry for the frustrated rambling, but I'm a little pissed. To add insult to injury, the damn service engine light is on - I'll have to check the codes when I get home tonight.

 

Hey 99HRDTP-

I was there when you put your car on the dyno. I had the yellow Z06. I was suprised to see those numbrs too! Your cam is bigger than mine (222/222/112) and I was disappointed with my 400.1 reading! The only tuning I have is from the diablo predator and I'm still running way rich. I thought for sure they would have the problem solved after I left. I really wanted to see that 150 shot reading as I am planning on a 100 shot. When Z06 CAM put down 410 without tuning and 423 with tuning with the red Z06(STOCK LS6 HEADS) I asked how much they charged for the dyno tune and was told $500. I thought it would be more along the lines of $300-$350. One thing I did notice on your line graph is that at a certain rpm on up, the line got really jagged. Maybe this info will help on the forum on a diagnosis. The guys and Angie are really cool, and from observing thier enthusiasm when they succesfuly tune a car I can tell they will do you right. Good luck with your car.

 

99HRDTP- First get the timing and fuel/air streightened out. Next you need a Z0-6 intake(good for another 15HP) and headers on your N.
A. motor. When my car was new with MTI top end kit I dynoed at 380 with headers. After the Z0-6 intake came out I increased another 16HP. That was 396HP. All this on three and onehalf year old technology parts. All the later model cars are stronger now from the dealer. Do not give up and you will be where you want soon. Good Luck :smash:

 

Dead Eye-

Thanks for the support, man. Your ride was lloking good Sat. I'll keep you posted.


Sack Rat-

I do have the LS6 intake manifold and long tube headers. Now you see why I'm disappointed. :mad

Is there a general consensus that it is worth the money for the dyno tune to straighten out my timing issues. :confused:

 

2 questions:
What cam do you have?

What did Thunder racing say about the low numbers and what do they suggest?

 

99HRDTP,

I highly doubt your headers or your intake are causing your problems here... bunch of crap with people telling to switch to other headers or intakes... i HIGHLY doubt, that is the reason why you are ONLY geting around 350rwTQ....

switching your bolt ons will not yield you another 30-40 rwtq or another 20-30 rwhp..... that is :bs

There is something fundamentally wrong here. Aside from questioning the tuning... you might wanna question the CAM that you chose and its characteristics.... 224/228 vs. 224/224, or 226/226 ? split vs non-split ? I am no where near an expert on Cams... but it is just a thought

aside from that.... my other question is:

What DYNO numbers did you get BEFORE the H/C work? (i hope you did a before and after)




[Modified by johnnyC5, 11:46 PM 12/2/2002]

 

johnnyC5- Not claiming bolt ons are the solution to his problem. Only trying to quantify other mods once the core of the problem is resolved. I agree something deeper rooted seems to be the problem. Turns out he already has the bolt-ons I was referring to hence his dissapointment. :yesnod:

 

Mike, What injectors are you running? I forget what came stock on a 99 (26 or 28?) but with a Katech StageII setup you really need the 28lb injectors.

:cheers:

 

I would take him at his word and go see one of the Texas guys for tuning and get some ZO6 28# or SVO 30# injectors. First he should be able to dial in you’re A/F to be a near perfect flat line between 4000 (if not lower) and fuel cutoff and not vary between 13 and 13.5. Also, he should have no problem fixing your KR problem. Finally, he should have recognized before the installation that the stock 26# injectors weren’t going to cut it.

I say this because before my H/C, injectors and tuning, I had essentially the same mods (minus headers) as you and was running off the chart lean with almost 10* KR. My injectors were running at a 85% duty cycle when you want no more than a 80% duty cycle. Now, everything is as it should be.

With bigger injectors and proper tuning another 20 hp. and more than 20 ft. lbs. of torque is not an unreasonable expectation over your (average) 387.6 hp and 351.3 tq., given the stage 2 heads and 224/228 cam on top of your other mods.

 

I agree with JohnnyC5. What did your car dyno before? If your car only dyno'd 285 and the guy who got 400 RWHP with your same package dyno'd 310 stock you can see where the problem lies.

 

2000^C5-

The cam specs are 224/228 581/588 114 lsa. TR suggested trying a tank of race gas to see if it helped. They also said they could "tune around the timing issues." One hypothetical suggestion was to drop out the low octane sensors.


JohnnyC5-

Unfortunately, no dyno before hand. I didn't realize I had a resource like TR only an hour away.


Bill-

I believe I have 26 lb injectors. Do you guys routinely swap out to the 28 lb injectors when Nate does these packages? What are your feelings about the need for a larger fuel pump? (I also run a 150 shot of N2O)


SFvetteman-

Thanks for the advice.


Quicksilver-

See above, no dyno pre-H/C. :(

 

For a comparison my Katech Stage 2 Heads with an A&A cam was about the same. The difference is I had the stock manifolds installed.

If you don't have Autotap go buy it. With the MAF ends I bet you don't know what your LTrims look like which can be holding you back.

I have the MAFT installed and I had to increase the base several %% to get the LTrims to read a little rich. Also at WOT I'm adding 8% more fuel.

 

Slight thread jacking here :reddevil
ddawson, we have very similiar cars!!! :cheers:
I also have a white coupe with MMS cam from A&A with A&A heads. My rotors are also DBA rotors. I have the same Momo *****, also Z06 swaybars. Damn, I have found my long lost twin brother :lol:

 

Don't forget the PVC mod :reddevil

 

And our rwhp are within 5 HP!!! :cheers:

 

99HRDTP,
I have an auto and the Katech stg II package stock injectors. I got 385 rwhp, so you should be higher. Call Chris at Katech and talk to him. He told me the new cams are doing around 400 rwhp, I bought my cam about 2 yrs ago.
Shawn

 

Are they're any parts in the valve train that aren't a part of the package ie. different valves, springs or retainers that are not part of the katech H/C combo? If so maybe it's a harmonics problem.

JFI before my header and catback install, Mine put down 364 to the ground. I know you still have the cats so maybe that can account for a 10-15 hp deficit.

 

Mike,
my cam specs are the same as yours. I was recommended the 28# injectors by Nate at Xtreme. '99-'00 injectors need to be replaced. I replaced mine w/ '01 Z06 injectors.
Also, not sure if you're still planning on spraying. If not, I would change to TR55 or the iridium plugs.
Let us know if you find the source(s) of the problem. You should be putting down around 400 rwhp if not more.:yesnod:
good luck!


[Modified by ModifiedC5, 4:26 PM 12/4/2002]