Headers + catless Y then nothing = good?

**dhillyard** · 07-30-2007, 05:23 AM

Hey guys I took my I pipe off the other day on my 02 T/A, and its making the most power it ever has

with my 315 nittos on, it still spins in first gear, granted its a 4.10 but still, it never did that till I took the I pipe off. So I was wondering if its true that running around without any pipe there will burn out my valves due to backpressure? My buddy told me that is what will happen at some point and I was not sure if he was correct or not. So please give me some insight! thanks

**SStriker** · 07-30-2007, 07:55 AM

when it gets cold you could risk warping the heads or so i have heard over the years. Honestly i wouldnt recommend it.

**Marc 85Z28** · 07-30-2007, 11:05 AM

That's a myth, and your friends an idiot. Backpressure is not necessary, and you're not going to burn a valve by lack of exhaust. If you ran an engine with no manifolds/headers for an extended time, maybe, but certainly not with open headers or an open y-pipe.

**dhillyard** · 07-30-2007, 01:05 PM

Well thanks man, I didn't really believe him either, I hear about lots of people not running exhausts on cars and being fine so thanks for the clarification.

**N20LT4** · 07-30-2007, 01:40 PM

Originally Posted by Marc 85Z28

That's a myth, and your friends an idiot. Backpressure is not necessary, and you're not going to burn a valve by lack of exhaust. If you ran an engine with no manifolds/headers for an extended time, maybe, but certainly not with open headers or an open y-pipe.

Sorry bud, that's no myth. No backpressure can be very bad for a street motor (i.e. stock valves), and I don't see why anyone wouldn't wan't a little torque down there on the street especially in an LS1 where low-speed torque is already an issue in my opinion. It's pretty much a toss up, but it's no myth.

**Marc 85Z28** · 07-30-2007, 08:48 PM

Originally Posted by N20LT4

Sorry bud, that's no myth. No backpressure can be very bad for a street motor (i.e. stock valves), and I don't see why anyone wouldn't wan't a little torque down there on the street especially in an LS1 where low-speed torque is already an issue in my opinion. It's pretty much a toss up, but it's no myth.

Really? Prove it! Backpressure kills overall flow and velocity and thus power. You can completely eliminate backpressure AND still keep velocity up. Eliminating backpressure and lowering velocity is what hurts low end torque.

Can anyone show proof of any engine ever burning an exhuast valve due to lack of backpressure?

Maybe I should go put a 20' long exhaust on my car with a 1" diameter pipe to save my valves and provide tons of low RPM torque...

**N20LT4** · 07-30-2007, 10:36 PM

Originally Posted by Marc 85Z28

Really? Prove it! Backpressure kills overall flow and velocity and thus power. You can completely eliminate backpressure AND still keep velocity up. Eliminating backpressure and lowering velocity is what hurts low end torque.

Can anyone show proof of any engine ever burning an exhuast valve due to lack of backpressure?

Maybe I should go put a 20' long exhaust on my car with a 1" diameter pipe to save my valves and provide tons of low RPM torque...

Simply Stupid. Not Even Worth My Intellegence.

**Marc 85Z28** · 07-31-2007, 07:02 AM

Originally Posted by N20LT4

Simply Stupid. Not Even Worth My Intellegence.

Go read David Vizard's book How to Build Horsepower. Then proceed to shove foot in mouth...

Intell e gence huh

How about that caps lock?

**SteelmanLS1** · 07-31-2007, 07:40 AM

I was told by a guy here at a local speed shop (Quality Custom Racing) that your stock motor needs back pressure to make the most power... I told him that I was going to run 3" pipe off my headers and dump it before the rear axle and he asked if I had head work or a cam? I said no the motor is all stock.. Well he went on to explain that a stock motor really does need some back pressure to keep it making power in all RPM's, without back pressure he said your power ban will only be from like 4,000-5,800, which being a stick might be alright... But he said if you have head work and a cam then yes, dump it or something because at that point back pressure is not necessary....

Just my .02

**0rion** · 07-31-2007, 08:28 AM

I've seen this argument before.......no one will win.

Ratdaddy07 · 07-31-2007, 09:24 AM

Like a lot of arguments here, but I gotta think if the thing is making more power and you don't here a calamity of horrible noises coming from the engine bay then you are alright. And who said low end torque is a problem? My only problem with low end torque is too damn much to get traction. Anybody else having a problem with low end torque? Anywhoo I think the thing is to find the right amount of backpressure, which is a bad term just plain old pressure in the motor itself which you increase or decrease with length and diameter of exhaust, headers etc.