Katech_Zach

I know, but that was the best answer I could come up with. We never tested cat delete only. I think a lot of that gain was eliminating the backpressure from cats anyways. Still, I think it's 10. The torque comes from the long tubes.

NemesisC5

Thanks Jason, that's about what I expected. I've heard too often that cats don't cost but 2-4 hp max but I could never accept that. I would like to see dyno results but know a modern performance company would have nothing to gain by testing and selling only "cat delete" pipes. I know the best exhaust solution is a well designed set of long tubes.

Trevor @ Texas Speed

Thank you for chiming in Jason and validating my best guesstimate! The 30 RWHP gains people are showing are with long tube headers in place. As Jason stated, long tubes are adding quite a bit of HP and TQ.

Suns_PSD

I tested a 3.8L V6 back to back with cat deletes vs the factory cats.

The car lost hp and especially torque everywhere WITHOUT CATS except over about 5800 rpm where catless the car gained a peak of a measly 2.7 rwhp. The torque losses going catless were in the 5-7 ft lbs. range everywhere

Now tuning that car was a challenge and it was already custom tuned (2x) so I was unable to fin out of custom tuning combined with cat deletes would have gained any power. Maybe there was something to be had there.

Either way, the noise and smell were awful catless. I'm just not interested in running a car that way even if I gained 15hp, which it won't.

Now whether or not the additional airflow of going catless would offer more benefit on a larger 6.2L pump, I can't say.

Trevor @ Texas Speed

The smaller engines definitely make it easier to lose HP and TQ. You certainly won't see a loss in power from the LT1 sans cats. If someone decides to run catless, they're typically doing it at the same time as a set of long tube headers. So, you see a nice HP and TQ gain from that as well, not just the removal of the cats. I, too, prefer to keep a catted setup because of the smell for most of my street cars. Even my '61 Chevrolet Parkwood wagon that has a 6.0L LY6 conversion has a set of bullet cats on it to keep the smell away!

4GS7

Does this cam keep VVT and AFM/DoD?

PRE-Z06

Nice job guys! Just for clarification, the ~520hp baseline was tuned correct? Makes the gains from just ported heads and little cam even more impressive if so.

Trevor @ Texas Speed

This cam retains VVT but eliminates AFM. We will have some cams that retain AFM for those wanting to do so.

As for tuning, the 518 HP baseline was with no tuning. We left the timing tables stock for all pulls and only changed the fuel as needed to get the a/f ratio back to comparable. We did not want to skew results with tuning changes other than what was required to keep the a/f ratio consistent as we changed parts on the engine.

NemesisC5

I like the way you adjusted to maintain factory AFR and left all other tables the same. It seems like a good baseline to baseline comparison for evaluation. I've seen more vendors do this with C7 than all previous generations put together over the years I've been on the CF. Thumbs Up Texas Speed

FASST LN

Given the removal of AFM, will you guys offer an aluminum drive shaft and what gains do you think will be seen there? I believe I read the C7 drive shaft's weight increased by 22 pounds over the C6 aluminum piece. I would imagine moving to an aluminum C7 driveshaft would provide solid gains across the entire rpm range!

CPhelps

Not that it changes your question but FYI it was the torque tube that was replaced with steel and gained weight.

FASST LN

Oops! Thanks for the clarification.

Suns_PSD

What the heck is a torque tube?

Thanks

FloydSummerOf68

Jason said that catless headers showed 10/19 on an engine dyno.

Trevor @ Texas Speed

I stand corrected. It looks like I misread. I would expect that the larger gains being reported with headers in place also include tuning.