Too much exhaust?

[Bansheemanche]

Hey,

 

I was wondering about getting a new exhaust setup for my manche. Right now it is all stock except the previous owners replaced that cat with a catco on and then replaced the muffler with a stock one. Now my tailpipe is all rotted out so I want to replace that.

 

Anyway I was thinking of just wanting to do a cat-back setup. So I will leave the cat there and run 2.5" pipe all the way back, no muffler. I live loud vehicals.lol Is this not enough back pressure or should I be ok as I do do alot of interstate driving with this thing when I drive it back home some weekends on the interstate going 75-80. She sometimes has trouble getting over 70 if the wind is right so I definatley don't want to lose power.

 

Thanks, this is for my 4.0L 5 speed manche

[86FUBAR]

This is what i did and i love it , i don't know if i lost any power (its been a long timesince i did this) but i don't care , its loud and scares old people :brows:

2 chamber flow with a 4" turn down and yes i cut a 4" hole in the muffler to match

[FxRacing282]

thats fine i run 3 1/2'' headers to 3'' to a muffler and ive got tons of power. 2.5'' for 4liters is definatly nice, but i would prefer a 2 1/4''. i say go ahead if you run into trouble just put on a neck at the tip

[undercoverwalrus]

i've got a 2.5 five speed in an '86 and i was thinking about going loud myself. i was thinking about a straight pipe from the manifold (no emissions testing in florida) to a cherrybomb glasspack to a turndown keeping the stock 2". i was hoping to get some more power out of the 2.5 (and it's really cheap too). good idea? :dunno:

[Eagle]

There is a reason the stock exhaust is 2-1/4".

 

Many years ago, when my brother was managing a Speedy Muffler shop, he talked me into replacing the stock exhaust with a 2-1/2" cat-back system. BIG mistake! I lost gas mileage, and I lost low-end torque. The trade-off is that you supposedly gain high-end horsepower.

 

But ... you're talking about a 5-speed with tall gearing. Your RPMs at 75 MPH are under 2500 RPM. That's not exactly the high end of the RPM range. You do NOT need a 2-1/2" exhaust to run down the highway at 75 MPH in 5th gear.

 

As for running with no muffler? One 25 mile trip and you'll regret it. I hope you have a good stereo with good speakers.

[Duner]

I thought the factory used that big flat spot on the down pipe to create the required backpressure. I can't see that it is there for any other reason, front drive shaft does not seem to be anywhere close to the pipe lifted or not lifted.

 

Or maybe someone ran mine over at the factory before they installed it.

 

For the record I have an after market converter, (no change in mileage) then 2 years later 2.5" pipe from converter to flowmaster 40 series and 2.5" out the back like the factory and I have great sound and improved mileage.

[FxRacing282]

i've got a 2.5 five speed in an '86 and i was thinking about going loud myself. i was thinking about a straight pipe from the manifold (no emissions testing in florida) to a cherrybomb glasspack to a turndown keeping the stock 2". i was hoping to get some more power out of the 2.5 (and it's really cheap too). good idea? :dunno:

 

well if i were you.... just kidding, if you want to go +2" then run your cherry bomb backward. this will give you some more back pressure and sound just as nice. and if you follow my advice, then no chrome

[Belto]

This is what i did and i love it , i don't know if i lost any power (its been a long timesince i did this) but i don't care , its loud and scares old people :brows:

2 chamber flow with a 4" turn down and yes i cut a 4" hole in the muffler to match

 

sorry if I'm highjacking the thread but can you post a sound clip off that set up?? thats what I plan on doing...

[86FUBAR]

I would love to post a sound clip of it but don't know how ? i have picture trail so could i do it through them ??

[Belto]

I really don't know,, most sound clips ive seen are uploaded on youtube and well taping the truck or car and reving it,, and idel... but if you have any vids of the MJ moving well I guess we can here it... :cheers:

[86FUBAR]

I really don't know,, most sound clips ive seen are uploaded on youtube and well taping the truck or car and reving it,, and idel... but if you have any vids of the MJ moving well I guess we can here it... :cheers:

i will try and finger somthin out to day

[Belto]

thanx looking foward to it

[Bansheemanche]

Ok thanks for the help. I will have to think on this some more.

[86FUBAR]

well this is the best i can do right now , the first clip the truck was cold and the second the trucks carb was unhappy with me :roll:

The vids don't do it much justice but its better than nothing

and my camera is garbage , but o well

[Confedneck]

i had an 88 XJ with a 4.0 that had stock manifold and down pipe... no cat, a 40 series flow where the cat used to be with a chrome tip clamped on it... sounded great, loud as hell, PLENTY of power...

 

 

the MJ will get a 4.6 stroker eventually... APN header, and 2.75" downpipe to a 50 series flow single in dual 3" out with dual exits right behind the cab... and should sound good

[FxRacing282]

sounds like a v6

[1986Comanche]

well this is the best i can do right now , the first clip the truck was cold and the second the trucks carb was unhappy with me :roll:

The vids don't do it much justice but its better than nothing

and my camera is garbage , but o well

 

sounds like a v6

 

Umm... It is a V6. He said the truck's carb was unhappy with him. Look at the quote above. The only motor used in the Comanche that had a carburetor in 1986 is the 2.8L V6. So it must have a 2.8L V6 in it if he's talking about carburetors. Also, his one video does say 2.8L V6 exhaust on it and the other one says 2.8 Comanche.

[A-man930]

I was thinking of a Flowmaster 70 series (nice big case for sound, but plenty of flow) and a nice mandrel-bent 2.25" or 2.5" system from the manifold, and possibly a high-flow converter. With a cam and intake upgrade, I would think the slight step-up in flow would maintain good torque.

 

By the way, those of you with turndown before the axle, do you get fumes building up under the cab when there's no wind?

[FxRacing282]

well this is the best i can do right now , the first clip the truck was cold and the second the trucks carb was unhappy with me :roll:

The vids don't do it much justice but its better than nothing

and my camera is garbage , but o well

 

sounds like a v6

 

Umm... It is a V6. He said the truck's carb was unhappy with him. Look at the quote above. The only motor used in the Comanche that had a carburetor in 1986 is the 2.8L V6. So it must have a 2.8L V6 in it if he's talking about carburetors. Also, his one video does say 2.8L V6 exhaust on it and the other one says 2.8 Comanche.

repeat after me; JOKE, JOKE, JOKE

[Belto]

sounds good,, thanx for the clips

[86FUBAR]

sounds good,, thanx for the clips

thanx but the vids don't do it much justice , i need a better camera :cheers:

[Belto]

sounds good,, thanx for the clips

thanx but the vids don't do it much justice , i need a better camera :cheers:

 

 

no prob I will still do my exhaust like that.. lol :cheers:

[92comanche4x4]

here's a sound clip of mine crappy video ill get a bettter one soon during the day i already make my nabours mad but it is a glasspack and it dumbs right behind the passenger door no cat ether I'm gonna do a stack one of these days also its a 4.0

 

[Belto]

just did my exahust, I did a 2.5" magnaflow high flow cat and a glasspack and a cutdown,, sounds like a beast