6Speeder

2015 Z06, M7. Previous dyno was with the Halltech CAI, 160 stat, Ported TB, and IW 9% overdrive pulley ON STOCK, FACTORY TUNE It made 650 SAE RWHP and 690 SAE RWTQ.

We added the Norcal cat delete pipes, went back on the same Dynojet dyno and with no further changes it made 673 SAE RWHP and 720 SAE RWTQ. Still on factory tune. The A/F and boost stayed the same.

Bottom line the pipes gained me 23 SAE RWHP and 30 SAE RWTQ. Color me happy! I'll put up the graphs when I get them.

3 Z06ZR1

Nice gains but talk about pushing the factory tune! I would say watch now for the 2 ft post telling how this is not possible but they seem to be on vacation or something!
Nice work!

C7/Z06 Man

What is the AFR & boost; idle (AF) and WOT (both)?

6Speeder

Closed loop the A/F is 14.6 or so. my LTFT's are +3 to +6 in closed loop. At WOT it starts out a little lean, just over 13:1, but goes down to low 11's with COT. The max boost is about 10.5.

TxTaxman

I'm very surprised by those numbers for sure. Nice gains.

Tennispro1986

Very nice. How was the install of the cat delete pipes? They bolt right up to the factory or aftermarket x pipe?

1QUICK Z

What mph are you in the quarter mile? Gotta be way over 135 with those numbers?

HessViper

I am new to the forum. I have been doing a lot of reading. I enjoyed the thread where you 6Speeder and MikeC7 were going back and forth. You both know your stuff. I do not own a corvette yet, just an 03 Viper, and if I do get a corvette, I am sure I would like to mod it but keep the factory warranty, so your threads are of great benefit for me to learn what is possible.

I feel like I am going crazy, the thread I was reading where you and Mike were debating, is now missing. There was a lot of knowledge in that thread, I believe you and he had predicted that the downpipes would not cause the car to run more lean, which surprised me, I would have thought the opposite, but if I am not mistaken, your AFR is the same ratio now as it was before you added the catless downpipes.

The thread was titled "top speed" and a few other words. I can't find it anymore.

HessViper

never mind, I found the thread I was searching for. Thank you again for all of your hard work to solve this for the rest of us. Keep us posted if you do anymore mods to your car

6Speeder

The Norcal pipes fit perfectly to the exhaust manifolds and the stock back pipes. I did not get aftermarket back pipes, the stock ones have an "X" in them and don't look that restrictive. I gutted them and now it still looks like I'm running cats.

6Speeder

Our track in Albuquerque is at over 5,000 feet altitude and due to heat is usually over 7,000 feet DA. I hate to give out my times/MPH because most folks don't understand how much higher altitude costs speed due to less dense air (less oxygen to burn with the fuel). That being said I have run 128 MPH in the quarter. I have beaten cars that have run 10.7 here, that's QUICK and FAST for here.

C7/Z06 Man

I have a gutted stock X-pipe in the shed. How long did it take & what did it take to gut? I'm thinking it took some time and was a PITA. Here's a pic looking down the barrel into the cat, even ground down some of the tubing edge on the other side of the converter. As far as that X-pipe part of the stock pipe it looks to me like it would out flow anything else on the market.

1QUICK Z

I understand that your elevation plays a role in your times at the track. Just curious how you are able to put up such stout numbers on the dyno? Especially at that elevation.

3 Z06ZR1

The dyno is the Norcal pipes exchanged and the rear cats hollowed out both not just the norcal pipe? I was thinking it was just the Norcal pipe? My headers run cats a must for me!
Thanks

6Speeder

The numbers were SAE, corrected to sea level. That's the only way to get an apples to apples comparison for folks all across the map, with different weather and elevations.

6Speeder

My earlier dyno numbers included gutting the rear cats, and I did not dyno that change because I didn't feel any seat of the pants change, nor was there any sound difference. I didn't feel there was a need to spend the time and money for a change that was probably within the limit of accuracy of the dyno. The last numbers I reported were for one change, the Norcal cat delete pipes instead of the stock catted pipes. That change alone, on my car, was worth 23 SAE RWHP and 30 SAE RWTQ.

3 Z06ZR1

Just thinking you would gained less with the cat delete pipe if not for the rear cats being gone. So the true number from just that mod on the stock car would be less. Then was a Z06 on the dyno when Z06 with upper pulley.2.31, AFE cat removal pipe and full corsa y pipe and AFE intake didn't make any where near your numbers. These dyno's do not read the same they vary widely between shops!

1QUICK Z

Yeah, I agree. I have similar mods (upper pulley, CAI, PTB and Borla x-pipe) and custom tuned on E50 and I'm only 630/630 on a Dynojet at near sea level elevation. I don't put much thought into a dyno number anyways. Which is why I wanted to know your mph at the track? That tells the true story. Just too many variables. My car runs great at the strip so I'm happy.

6Speeder

Yes, they do vary. That's why I always use the same dyno. I dyno after every major mod, the purpose is to if the change is worthwhile and delivering what was advertised.

BTW: As a point of reference a 2019 ZR1, A8 dyno'd just before me, his numbers were 636 SAE RWHP and 660 SAE RWTQ.

3 Z06ZR1

Hearing you were at 650 rwhp with just a Halltech and 9 percent lower on the factory tune is amazing after hearing the ZR1 made 14 rwhp less. why buy a ZR1? Surprised to hear when the 2.31 upper and AFE
intake AFE cat delete full corsa x pipe and catback struggled to get 630 while tuning on my tuners dyno. With a butt load of less RWTQ. They do vary! Just saying!