BJ67

They use the same part # heat shield, I would think they are exactly the same from the outside. Part #s are indeed different for a zo6manifold,price is $420 versus $85 for the cast iron ones. Now I wonder why chevy did that, stainless steel honed to flow better than cast iron?

goec2468

From what I have read and seen, the astings are exatly the same, only the material is different.
Also the Surface Looks the same, so I would not expect them to flow any different.
Stainless steel can withstand much higher temperatures for longer time than than mild steel, I assume that is the reason for the stainless manifolds of the Z06.

BJ67

Is stainless any lighter than cast iron, would be nice to think there is another reason beside heat durability. I always thought cast iron was the most durable exhaust manifold material , but heavy.

goec2468

Cast iron might be more durable than thin wall headers, buut not than cast stainless steel.
From what I read here in the forum, the stainless steel manifolds are heavier than the cast iron.
A forum member put both on the scale.

BJ67

So no performance difference, heavier and more expensive. The chevy engineer's have access to the best header manufacturers , use light tubular headers and get the benefits ,shame on you Chevy, just another Z06 let down... And I love corvette's and Chevrolet.

NSC5

From GM Powertrain's document at the launch of the LT4:

"Exhaust Manifolds
The LT4 exhaust manifolds are constructed of cast Austenitic Stainless Steel. The smooth flow passages and equal length runner geometry were carefully developed using CFD analysis to maximize the volumetric efficiency tuning of the exhaust gas flow.

LT4 exhaust manifold flow performance is equivalent to the LS7/LS9 tube and jacket design at lower overall cost, optimized exhaust sound characteristics, and more consistent exhaust flow.

The manifolds are fitted with a pair of close-coupled catalytic converters that heat quickly, achieving light-off temperature and closed-loop operations in seconds. "

Higgs Boson

lighten up, francis. you can spend another 300k for the same performance if you want to avoid "exhaust manifold disappointment" but I say just spend 1500 and put on some headers.

the corvette, camaro, mustang, etc are meant to be modded. they come at a price point based on MASS production. if you want a car that comes modded, so to speak, then you need to look way up in the McLaren range of the industry. have fun!

BJ67

That makes sense now, the Z06 stainless exhaust manifold flows consistently better than the mass produced inexpensive cast iron units.

HorsePower Junkie

Here''s what I would really really like to know...

ls the exhaust PIPE size, the exhaust PIPE diameter, it that the same size on all 2014 - 2017 Corvettes?

Is it the same on Stingray, Z51, GS, and Z06???

What is the exhaust PIPE size, what is the exhaust PIPE diameter??? ...and is it the same on all C7 models???


.

BJ67

All the individual pieces of all the C7's will fit each other. If you got a OE part from a Z06, that part will go right on a base stingray meaning all the inside diameter's are all the same. Its all based on a 2 3/4 pipe

goec2468

I am afraid the Z06 doesn't flow any better than the stingray manifold, internally they are exactely the same and they bolt on right on the stingray.
The only real difference seem to be the material and maybe the wall thickness.

555ctsv

Sorry to bump an old thread, but this is what happens when you search first

I just picked up a 2016 Z06, previous owner did a muffler delete. Found a local guy selling an NPP system from a stingray so it has the AFM valves ahead of the mufflers.

If i bolt this system onto a Z06 and there are no motors/actuators connected to the AFM valves, is there any chance of them slamming shut under load? The springs are pretty tight, but without the actuators connected to them i suppose it would be possible for the exhaust flow under WOT to potentially move them right?

BrunoTheMellow

If he's selling the complete catback npp exhaust, it should have the valves and actuators.

555ctsv

I already bought them, it's just the axle back without the actuators. He had to use his actuators on his new system.

I may just have a shop do a spot weld on the outside of the valves to make sure they cant move

Bill Dearborn

Even open I imagine the valves restrict exhaust flow to some degree. Is there a way to cut them out and weld the pipe shut where the shafts came through the pipe wall?

Bill

555ctsv

I left a voice mail with one shop yesterday and they haven't called back yet. 2nd shop looked at them and to do it off the car they would need to build a jig for each muffler to ensure the pipe alignment with the muffler doesnt change, and they didnt think doing it on the car would be an option due to lack of space to work.

I had NPP with AFM on my previous 2 stingrays. First one made 690rw second one made 773rw with these afm valves open so if they do restrict some when open i can't imagine it is much. Not enough to warrant the cost the muffler shop was asking as least!

I just turned the valves again and man i cant imagine any air being able to push against the tension springs that hold the valves open. I think ill just grab some metal zip ties to lock them in place to ease my mind

Gotta do something soon, the neighbors are already eyeing me! Road in front of my house is really steep, cold start and climbing that slowly in the mornings is way too loud right now with no mufflers

Toysrus

Sorry to revive an old thread once again but I am confused. If the exhausts are all the same, why am i seeing warnings on x pipes claiming they are only good on the naturally aspirated cars?

BJ67

Should not make ant difference imo. The pluses and gains from a secondary cat delete xpipe should and does pertain to NA or boosted alike.

BJ67

I believe the GS has no valves also.