keeso6z

I just got my 2006 Z06 back from 21st Century Muscle Cars after adding 21ST CMC Stage 2 CNC ported LS7 cylinder heads with tumble polished intake valves, stainless exhaust valves, bronze valve guides, .020 mill and .685 lift BTR dual spring kit, Dynatech stainless long tube headers, with high flow cats and X-pipe, Elite engineered insulated tunnel plate and a retune. The car made 507rwhp and 465.9rwt on the dyno.

Prior to these performance upgrades, I had them add a Calloway CAI and dyno tune. At that time the car made 482.5rwhp and 442.2rwt on the dyno. So I have picked up another 24.5rwhp and 23.7rwt with the latest mods. I was hoping for 30rwhp, but I thnk anything over 500rwhp with the stock cam is pretty good.

The car only has 2,300 miles on it, but I decided to go ahead and take care of the heads/valve issue to be on the safe side and at the same time up the performance a bit with the higher compression, ported heads. I have stopped short of adding a cam because they talked me out of it based on what I told them about my driving and what I like about the car. They said it would alter the drivability and I would get a smell out of the exhaust, both of which I didn't want. However, Matt said I left 40-50rwhp on the table without going to a mild cam.

From what I have read on many threads, my car should be able to hang with a C6 ZR1 0-60 and the quarter mile, but after that, the ZR1 is going to walk away. Also, I see that on the fast list, bolt-on C6 Z06s are doing high 10's in the quarter mile, so I would think mine might be in that league now given I have also done the heads. I'm not into racing or tracking the car, but wanted to improve the performance and take care of the heads/valve issue. Probably going to stop here, and happy with the results. I did notice on the dyno graph that the HP gains start to be noticeable after about 4,000rmp and the maximum difference with the heads and headers is coming at 5,500 to 6,000rmp. So most of the gains are up top, rather than down low on the rev range. It still makes more power down low though.

21st Century does excellent work and are highly reputable shop in the Dallas area. They are the guys to go to for this stuff - no question about it. Very professional, knowledable and honest. They don't talk you into something if they don't think you will like the changes in the way the car drives.

outhouse

AS long as your having fun that's all that counts! Enjoy the beast!



Not the first time someone was talked out of a cam on poor advise.


The right cam choice is all that is needed here. With stock exhaust I have no smell and perfect drivability out a katech 116 clone. Would not hesitate to do it again and this is my daily driver rain or shine.


I have a feeling all their cam advise is geared towards track cams. When it comes to street driven Z06's AHP has excellent advise, and I followed their build design matched to my needs.

kbreese

Just a guess, but maybe some shops don't want to spend the time or simply don't have the ability to PROPERLY tune after adding a cam? If that was the case here, AT LEAST they were courteous enough to not steer you into a cam they weren't going to spend the time to fully tune, unlike some other shops who just want to show the customer a peak dyno number and then they drive away with a car that has a terrible exhaust smell and compromised drivability.

As far as your gains go, it's certainly minimal relative to all that money spent, but at least you addressed the valve issue, and have a step up on a stock one.

outhouse

Not at all, I did the work myself and enjoyed every minute of it and by adding cam to ported heads and MSD intake and cai I now have a 600HP DD that I can sneak through smog simply by ditching the cai every two years.


I think the cam was only 700 ish more since I did it all myself and gave me the largest gains.


With the mods you have the poor engine is begging for a cam

Dan_the_C5_Man

My build is very similar, with the addition of an MSD intake.

I anticipate betwwen 510 and 515 RWHP. Unfortunately, my plans to carefully document the before and after results were derailed - the Dynojet shop I've used for the last 15 years, I learned the owner died a few weeks before I started to call to make an appointment to get the final post-mods numbers.

I guess I can check to see if a new owner will continue the business. It's a sad story, he wasn't that old but he did not take care of himself.

phipp85

We can do a "roll race" down the back straight at Road Atlanta. The old school asphalt dyno

EdsC6Z06

I did elect to go with a mild cam during my similar build. (Katech 116) Its a very driveable cam but you still lose that tractor grunt that the stock cam has off idle. Otherwise it's a different (angrier) animal at higher rpms. I love the car on the track but sometimes miss the stock cam on the street just cruising.

zblackz06

How is your cam at idle? Did it retain your stock driveability meaning if you are in 1st gear and let the clutch out will she drive around or buck?, I have the same cam but I also have a tuning issue so I don't even want to drive mine until it is fixed.

danziger

I like the gains! I'm looking for a mild performance set-up as well when I have the heads done. I probably will do something similar to yours, but am still weighing a mild cam as well.

keeso6z

One thing I noticed after the exhaust mods is there seems to be more of an exhaust smell from the car when I pulled it into the garage. I guess that comes with territory when going with high flow cats since they probably don't do as good of a job filtering the pollutants. I should probably get a Nissan Leaf now to offset my emissions.

kbreese

outhouse, I'm not sure why you thought my post was to you, I was commenting to the OP. He spent a lot of money to only gain 24 hp/tq.

I agree with you, he should have done a cam even if it's a mild one. That's the key ingredient in the formula in terms of gains.

With that said he still has PLENTY of power for a street car, with full stock drivability. But it's a lot of coin to spend for a mild bump in power.

keeso6z

I would have to agree with you. Not sure I would have done it now as it was not worth the money. I would have done the heads/valves, but probably not the exhaust. The car feels a bit stronger, but most of the power increase is coming in the upper rev range. What I don't like is the exhaust smell from the high flow cats. Matt tells me that if I went with cam, the smell would be exponentially worse, so glad I didn't go that direction. I am going to go retrieve the stock exhaust and hold on to it as I did the stock intake just incase I want to sell the car down the road.

outhouse

It would be my eyesight and a K and some EE's in your name being close to his and my slow brain LOL


kbreese
keeso6z


I'm in my 50's you cant sneak up on a guy like that

Les

Dan_the_C5_Man

Yeah, you have a cam.. There is a trend here -- you have more HP, more grip.. The only way I am going to "win" is if I blind fold you, or maybe let some air (all of it?) out of a tire or two, OR I could beat up on you for a few laps at a new-to-you track, at least until you learn which direction it goes..

But to your point, I do plan to dig up the stock roll-on numbers from the mags, find a flat area, see how the post-mod car stacks up. And before anyone suggests "why don't you just go to the drags to get a time?", a: I don't feel comfortable putting this car through that type of abuse, b: I'd be **** at shifting quickly, it would be a wast of time.

EdsC6Z06

Easing out the clutch in 1st is still doable but the feel of instant torque is not the same. Doesn't really buck, but I rarely try this without adding some throttle. As much as I miss the ultra low rpm torque, the power gains above 3k rpms are worth it!

Suns_PSD

Dude, this car is dying for a cam! What are you thinking?

My little LS3 has a baby cam and it still offers perfect street manners, power right from idle, and significant gains everywhere.

You can get it all in a cam as long as you don't go overboard. Katech Torquer all day Bro.

keeso6z

I hear you, but cams come with negative side effects and Matt has been pretty defiant on this based on what he knows about me. The main thing I don't want is the nasty exhaust or gas smell. I have it somewhat now with the high flow cats because they don't do as good of a job filtering the emissions as the stock cats. But not to bad. Matt said it would be infinitely worse with a cam. Also, I don't want the surging or higher rpm required for cruising in a higher gear. I like the way it drives stock. I'm not going to be racing the car or tracking it, so I felt this was a good place to stop. Not to mention the extra money for a cam. This car is sort of a collector/hobby car for me and will see limited miles put on it.

MTPZ06

I won't peer pressure you into a cam...lol. I chose to fix the heads and stay stock cam as well. I will say, that if I ever change my mind...my choice will be a custom "baby" cam from Cam Motion....period.

outhouse

Well that is where he is misleading you. We told you a long time ago its not a problem.


I had more smell stock then now.



We also told you that is not a factor with a mild cam.