Trevordickya

I'm looking to buy Holley Performance Flowtech Shorty Headers, and was wondering how the performance difference was and how many hp it adds.

austinjoe13

It will add 400 ponies.

austinjoe13

Just kidding, maybe 10hp at the crank so 5 to 7 at the wheels. They alter the exhaust note a bit and help the engine breathe better. When I put the header in my old jeep, I gained a solid 3mpg, but I also had the exhaust run in 2.5" pipe and it was straight piped with a high flow cat from performance curve.

If you want performance, pair it up with a good cowl intake, a bored out throttle body, and upgraded fuel injectors. Bolt-ons aren't going to get a whole lot out of the 4.0. Throw a cam in it for a real change.

Lowej82

Can I cut the muffler off a 96 xj somewhere after the cat without causing any damage to the motor after awhile without it?

Trail rig not driven on the street.

odgreen

If you enjoy carbon monoxide poisoning then sure

Lowej82

guess I should have been more detailed
, I plan to add more exhaust pipe just don't want muffler or anything besides the cat on it.

LiamLikeNeeson

I thought the catalytic converter was meant for the carbon monoxide?

odgreen

It doesn't eliminate it.

jay_sco

And what is does convert turns into carbon dioxide, not really any better to be inhaling.

Trevordickya

Okay thank you. Also looking into the d.u.i performance distributor and any info on it would be greatly aplreciated

LiamLikeNeeson

Oh ok that makes sense. Thanks. Spot welding it back on for now can help me pass the smog check right?

jay_sco

Yes. You won't even pass visual inspection without one. Why is yours off?

odgreen

Why would it need smoged if it's a trail only rig?

LiamLikeNeeson

I have no clue. All I know is my mechanic said it broke off the welds and it's a cheap muffler. No idea what brand because my dad had it installed ages ago.
It's my DD. If I were to get a new car it would be my trail rug but don't have the money

jay_sco

So...is your cat falling off or the muffler?