3.5" Exhaust for 2018 Tahoe 6.2L?

You guys are way overstating the "problem" of 3" aftermarket exhausts. A 3" system is likely to actually improve the power curve for the way most people drive these anyway as a larger system might actually lose you some torque in the middle of the power curve where you don't want to. If you don't at least have a whipple or similar on your 6.2L then I think you are kidding yourself about exhaust and the effect of larger pipe.

As far as Duramax's go I've personally seen more than one "sleeper" LB7/LBZ Duramax making well over 500whp on the factory 3" exhausts (I really think 600whp+ but I'm being conservative). My LB7 with a built trans and upgraded turbo stood no chance even with my giant 5" exhaust.

Some of y'all might benefit from watching 'Engine Masters' on Motor Trend TV. They do dyno comparison testing, in-depth and technical.

joe

I would worry about your flat section in the y pipe first.

Thrust said:

I would worry about your flat section in the y pipe first.

Click to expand...

Did you replace yours with something larger and get a worthwhile gain from that?

J5races said:

Whipple claims the Gen V kit makes 535hp to the wheels. I gotta think bigger exhaust piping will help at that power level.

Click to expand...

Maybe so, there's a math formula for that but I don't remember it anymore. Banks and Hennessey are on top of that, I'd ask them.

As stated above, bigger diameter exhaust piping is NOT automatically better. There is an actual 'tune' of exhaust fumes air flow, volume and velocity, involved in exhaust system engineering. With too little piping diameter, you get restricted flow due too much exhaust fumes trying to flow through the piping, with a resulting back pressure and a slowdown in exhaust fume velocity through the piping. With too much piping diameter, you lose the exhaust fume velocity momentum achieved from from the exhaust manifold/headers, and you get velocity dead spaces in the downstream piping, with a resulting slowdown in exhaust fume velocity through the piping.

The factory 3.5 inch moves plenty of air. One of my trucks runs a single turbo 416 stroker through a factory 3.5 exhaust and muffler (no cats or y pipe,) and makes 900 hp. I am building a single turbo srt10 right now that is way bigger of an engine than the 6.2, and will make around 1000 hp, and it is only running a single 3.5 inch exhaust. Just change your muffler for sound if you want it louder, as for flow, your whipple is a fart in the wind for a 3.5 inch exhaust. Heck, I made 720 wheel hp through a single 3 inch once on a supercharged fourth gen camaro, and 3.5 inch is a massive increase in flow over 3 inch.

These guys make great stuff. I have a full system from them on my 800hp Sierra. They are spendy though.

https://stainlessworks.net/by-vehicle/gm/tahoe/

When I last shopped for a 3.5" exhaust for my Avalanche (admittedly it has been a few years) some of the Escalade aftermarket options were 3.5" and should either bolt up or require minimal mods. Another option would be a 3.5" takeoff, delete the resonator and swap mufflers. If your 6.2 already has the 3.5" factory exhaust, that's probably the route I would choose.

I have seen those engine tester video's one in particular they take a sledge to the stock exhaust smashing it on purpose to restrict the flow and it made no difference other than at one point while making various smashes and re-testing power actually increased.
as noted already the stock 6.2l pipe is already 3.5 or larger in some spots, your pretty much waisting your money, if you can find 4" pipe then order it and have a local muffler shop build you a exhaust. most places do not even stock 3.5" let alone 4" and good luck finding a 4" muffler, probably have to modify a straight thru one like a borla
4" will make it louder, I put 3.5" on my 03 5.3 silverado you could certainly hear the difference. did it make more power? no idea, sounded good though