Kracka

Excellent! If you happen to find a set listed online feel free to pass it along.

Kracka

Sounds like they found a set for you!

Kracka

Back from the coaters:













Now the real fun begins

Redvette_22

I've been emailing with Mr. Carey and I think we have a deal going.. Today's latest email from me gave him authorization to get a set and do the job.......

Kracka

Glad to hear it!

Redvette_22

Today I spoke to Ian Peterson at MAP and all the details are taken care of and the order is underway. I hope that I will be provided with flow and balance numbers, before & after, and with the dragstrip logs and information I currently have, we can see how the performance will benefit.....now when do the tracks re-open....LOL...I can't wait..

Kracka

Anxious to hear your results as well! The C7 manifolds should be on my doorstep Monday.

Redvette_22

Kracka, the next time I go to visit my daughter in Princeton, TX maybe we can meet. It would be great if we went to North Star Dragway (if I drive down again with my Vette) and we can compare drag times, and I'll even bring my daughters Hemi Challanger.

Kracka

Let me know next time you're down, and I'll do the same regarding my travels to NJ (my grandfather lives in Whiting...not too far from ECS much to my surprise). It appears Brick isn't far from him...mmmmmm Jersey Mike's...I actually spent some time on the Shore in May.

Kracka

After battling a busy work and holiday schedule, I finally got the opportunity to have these manifolds installed, along with a before & after dyno chart. The work was performed by 21st Century Muscle Cars in Addison, TX. To give you an idea to the install difficulty, the complete process only took them 3 hours, which includes both dyno pulls.

+11WHP/+8WTQ

I'm very happy with the results, and they said they were surprised by the gains too. These should remain emissions, warranty, and stock tune friendly by retaining the stock pair of primary cats. If you opt to leave the manifolds uncoated they will look identical to stock from the outside, but even coated you can barely they're modified once hidden underneath the factory heat shields.




Flow bench results (originally posted 11/25/14):
CFM (Y-axis) by runner (X-axis)

Dark line = ported
Light line = stock


Well, there you have it, laboratory and real-world results

Full mod list:
-AFE intake
-WeaponX ported throttle body
-MAP ported & coated exhaust manifolds
-Borla X pipe
-Diablo InTune (custom DiabLew tuned)

dovervold

Nice work Kracka. I have the exact same mods except the ported manifolds. If I don't go cam and long tubes, I am going to add the ported exhaust and hang on to the factory warranty. 440 at the rear wheels with a fat curve looks pretty nice to me

Redvette_22

Kracka, I forgot, is your car a stick or auto?

Kracka

Feels nice too! Great setup with stock-like drivability.

Kracka

Stick

Bill Curlee

Kracka

I applaud you on your work. The time and expertise that was spent on these manifolds and the research on flow and HP/TQ improvements is OUTSTANDING! Well done! Not many people would have undertaken this project. You did it and did it extremely well!

I have a few questions if you don’t mind?

- Internal port and outlet reshaping:
Did you maximize it or just clean it up and straighten the inlets and outlet mouth? If you would have done more grinding and shaping, do you think it would have made a little more difference or would it have reduced reliability?

C7 EXHAUST MANIFOLDS:
I have a 2011 Grand Sport. Are the C7 Manifolds & CATs & midpipe a direct bolt in fit for a C6?

Would the C7 manifolds bolt on the a C6 ZO6 exhaust system?

If not, can the C6 ZO6 cast iron manifolds yield the same results after porting? Do you think stainless steel vs cast iron makes any difference in performance vs reliability after porting.

INTAKE MANIFOLD IMPROVEMENTS:

Have you thought about hand porting and improving the flow in the intake manifold?? Do you think it would make a worthwhile difference?
Do you think that the combination of intake porting & exhaust porting would start to have an effect on OEM tuning?

I know that the C6 intake manifold yields HP/TQ improvements after porting.

Thanks

Bill

Higgs Boson

there are already several companies porting the stock intake with good results.

Kracka

First of all, thank you for your feedback, I appreciate knowing that others find this type of data interesting and/or beneficial. I'll try to address your questions in order.

1. You do have to keep a certain amount of wall thickness otherwise you will sacrifice reliability and increase your risk of cracking the manifold after extensive heat cycling. These manifolds were ported with a few things in mind, and working towards the ideal balance of reliability, durability, overall flow, and balance between runners (or reduction of imbalance). Yes, they could have been further ported, especially in the collector area, but it would have been at the expense of balance between the runners. Ideally, all runners would be completely identical in flow, but in the real world that is not possible. The improvement in balance, and ultimate flow, was quite impressive though when you look at the flowbench data posted above.

2. C7 exhaust components are not interchangeable with C6 components, but they are just as workable in their own right. This shop has also done C6 exhaust manifolds for another CorvetteForum member and the results should be about the same since the manifolds are similar in design.

3. Both cast iron and stainless steel manifolds are good candidates for porting (and ceramic coating). Stainless steel does have advantages, such as lower weight, higher strength (better durability), and lack or surface rust (all at a higher material cost of course, which is why you see it on the Z06 but not the base models). SS does take more time and effort to port than cast iron, but it can be done regardless.

4. The stock LT1 intake manifold is a bit more of a challenge since it is plastic rather than a cast metal, but I do have one being worked on so we can find those benefits and areas for improvement first hand. I don't have a hard timeline yet, but you can expect similar flowbench and dyno data in the somewhat near future (I'd guess sometime during late Q1 2015).

5. It's tough to say on the stock tune compatibility until I actually get the car on the dyno. In theory, keeping with the stock design, the MAF should be able to compensate for the increase in airflow. I won't commit to anything one way or the other though until I actually see the AFR readings on the dyno, and how the fuel-trims are affected on the street. I am confident no check engine lights or error codes will be created though. It is safe to say, the more modifications you make, the better candidate you are for a customer tune. Luckily there is no shortage of competent tuners available on CorvetteForum, both local dyno tuners and remote email tuners.

Kracka

A quick update on the above comments. The more I look into it, the less I think this would be a worthwhile upgrade. As far as I can tell, the only real difference in LT1 vs. LT4 manifolds is the metal (cast iron vs. cast stainless steel). The SS is probably worth a few pounds of weight savings, but at this point I need no need to test a set for two reasons:
1. Cost - new LT4 manifolds are ~$400 each vs. $75 each for the LT1's
2. Similarity in design (as shown below).

2014 LT1 (Stingray & Z51) cast iron exhaust manifold:


2015 LT4 (Z06) cast stainless steel exhaust manifold:


Unless I stumble upon a used set for cheap, I probably won't bother. It was worth a thought though!

marcouvo

Looks to me like from the photos the stainless steel manifolds have the bolt holes for the C7 heat shields. Is that correct?

Thank you very much for the excellent work and sharing it.

Kracka

From my research, the heatshields are likely identical/interchangeable.

You're welcome!