pooled

I am installing my long tube headers, I just got them back from getting ceramic coating. Right now my exhaust is separate straight exaust with flow masters at the rear. My question is, should i pay to have my local exhaust shop add a cross to make an H pipe mid way, keep it the way it is? Also, if i came across a cheap used X pipe would that be better option?

This is on my C-4, basically stock, minus air pump, no frisbee, TB coolant bypass. In the future maybe a year I will be getting better heads and a better intake.

Thank you

Tom400CFI

I think there should be some connection between the two sides...I think the location in the system is far more important than if it's an "H" or and "X".

sstonebreaker

Engine Masters did a show on this. The X and H pipes both made about 10 HP more than the straight pipes, and both Freiburger and the other guy (I can't remember his name) liked the sound of the H pipe the best, as I recall.

pooled

Really, do you remember what vehicle they did the test on, just curious? I had no clue it made that big of an effect over straight pipes, i always thought they would be maybe 2-3 hp over straight, and 10 over a Y pipe.

pooled

Do you know where it should be located? like maybe 2 ft past the end of the headers?

Tom400CFI

Maybe. Testing or exhaust calc's would give you a good idea.

Do a search for exhaust design and there are some good articles about it to let you do your own calcs and design.

C409

….. I have an X on mine … on a C4 , positioning is determined by the transmission and the tunnel … 3" pipes , Summit bullets , and 50 series Flowmasters … great sound , NO drone … and they run 6.7's @ 100+ in the eighth …..

pooled

Im going to take a photo of how mine is laid out today, and post it on this thread.

sstonebreaker

It's not that critical. Optimum placement will net you a couple more hp, but in reality you're going to have to put the X-pipe where it will fit under the car. Unless hundredths of a second at the drag strip are important to you, a 4 or 5 hp difference isn't going to be noticeable.

65Z01

I've read that the X should be placed (as close as possible) to where the pipes are the hottest.

My question is do you prefer the sound of the old (say C3) Vettes vs newer Vettes with a connection between pipes.

Kevova

It depends a little on how you.layout you exhaust. It was recommended to paint 18 in of pipe attaching to header collector, crossover goes as close as possible to where the paint stops burning .

vader86

It doesn't matter if its H or X, but a connection will help reduce resonance. It wont make much power difference on your car, and there is only so many places you can put it.

Preferably closer to the headers though.

cv67

Do what you can afford, had all and no crossover cant feel a difference from any
Ready to go back to straights with a very long turbo
'
Real mods are made INSIDE the motor same as usual

project C4

I just found and watched the Engine masters episode with the straight vs H vs X pipe comparison. They used a carbureted 5.3 ls motor with a cam swap. 3/4' primary headers with 2.5 inch exhaust pipe and straight through Gibson mufflers. Peak horse power with the straight and the X was 362. The peak horse power with the H pipe was 360. There were slight gains in torque with the H and X in the lower RPM range.

pooled

did they dyno it without the h or x, just straight pipe?

Pwnage1337

I put an X on my car and the girls love it so much I can't drive my car downtown because they flock to it like bees to honey

Pwnage1337

Also my car is hella low because girls love a low low with 400 rwhp

A95Y

Where did you get the bends for your header pipes?

Thanks

06_LT1

I run a custom x-pipe my muffler guy fabbed up for me, installed in place of the factory resonator. With a stainless chambered exhaust, it's VERY quiet at idle but loud enough to frighten my wife (driving in front of me) when I get on it. No idea if it makes any more power, but it's significantly lighter than the piece it replaced.

C409

….. I bought a used Stainless Steel 3" B&B system for LT1 cars minus the resonator … the B&B mufflers were on the car for about 2 days and droned so bad that I couldn't drive the car … at one point , the car was idling in the driveway with the garage door open (attached garage) … I went into the house to get my sunglasses and the cupboard doors in the kitchen were all vibrating and making the strangest noises … I drove straight to the muffler shop that installed the mess and had 'em put the Flowmasters on … What a relief ! ….. The X was an E-Bay purchase …..