back pressure in exhaust

[Sroken Silver 5.1]

I just got my 1998 Mustang GT on the road from a trade and when I take my foot off the pedal I get some serious back pressure from the exhaust. The car is heavily modified and has 4 different custom tunes, I will outline for you..I just want to know that is there a way to limit the about of back pressure or getting rid of it completely.

Here are my tunes as they are now..

1: Mild Street
2: Aggressive Street
3: Mild NOS
4: Aggressive NOS

I do not know which the differences are but the former owner told me it is mostly airflow/fuel/timing combos..

you can see the list of mods I have in my sig...

 

[Willis_98GT]

Jeasus christ, you weren't kidding.. about your mods

you should take it to a shop and have the tunes evaluated.

 

[Sroken Silver 5.1]

Thanks I was thinking of having the tunes looked at again....Good suggestion..

Thanks, yea the car has everyting you need...I traded it for my 1990 Mustang GT w DSS 331 Stroker and Kenne Bell S/C...

 

[justinschmidt1]

Sounds badass...but 600 rwhp sounds a bit high to me.

Anyway....I guess your talking about the popping sounds from backpressure when you rev it up and let off right?

My brothers car did that but stopped after he had a custom tune made by the best.

 

[Sroken Silver 5.1]

Sounds badass...but 600 rwhp sounds a bit high to me.

Anyway....I guess your talking about the popping sounds from backpressure when you rev it up and let off right?

My brothers car did that but stopped after he had a custom tune made by the best.

It has a SCT Professional Tune by John Lund and if he says it had 600RWHP then I belive him...Cannot get much better then John Lund tuning your car. How many people do you know that have a 4.6 Stroker?????

 

[realitygt]

Sounds badass...but 600 rwhp sounds a bit high to me.

Anyway....I guess your talking about the popping sounds from backpressure when you rev it up and let off right?

My brothers car did that but stopped after he had a custom tune made by the best.

It has a SCT Professional Tune by John Lund and if he says it had 600RWHP then I belive him...Cannot get much better then John Lund tuning your car. How many people do you know that have a 4.6 Stroker?????

i'd say if you were blow you'd get close to that. but from what i see as far as mods, it's bolt on's and a .5L stroker with aftermarket heads. no mention of cams or a blower.

the 100 shot will definitely get u up there. maybe the "agressive nos" is like a 250 shot lol

 

[Sroken Silver 5.1]

Sounds badass...but 600 rwhp sounds a bit high to me.

Anyway....I guess your talking about the popping sounds from backpressure when you rev it up and let off right?

My brothers car did that but stopped after he had a custom tune made by the best.

It has a SCT Professional Tune by John Lund and if he says it had 600RWHP then I belive him...Cannot get much better then John Lund tuning your car. How many people do you know that have a 4.6 Stroker?????

i'd say if you were blow you'd get close to that. but from what i see as far as mods, it's bolt on's and a .5L stroker with aftermarket heads. no mention of cams or a blower.

the 100 shot will definitely get u up there. maybe the "agressive nos" is like a 250 shot lol

This post is not to defend what I have in the car or what it can do..but just for FYI....prior to the upper and lower control arms going in the car did 11.01 pass and that is spinning 65feet off the line...I did not put a Transmssion in that is rated for 700HP and cluch that is rated for 650hp to support something I do not have...Please lets get back on topic...

 

[justinschmidt1]

Sounds badass...but 600 rwhp sounds a bit high to me.

Anyway....I guess your talking about the popping sounds from backpressure when you rev it up and let off right?

My brothers car did that but stopped after he had a custom tune made by the best.

It has a SCT Professional Tune by John Lund and if he says it had 600RWHP then I belive him...Cannot get much better then John Lund tuning your car. How many people do you know that have a 4.6 Stroker?????

i'd say if you were blow you'd get close to that. but from what i see as far as mods, it's bolt on's and a .5L stroker with aftermarket heads. no mention of cams or a blower.

the 100 shot will definitely get u up there. maybe the "agressive nos" is like a 250 shot lol

This post is not to defend what I have in the car or what it can do..but just for FYI....prior to the upper and lower control arms going in the car did 11.01 pass and that is spinning 65feet off the line...I did not put a Transmssion in that is rated for 700HP and cluch that is rated for 650hp to support something I do not have...Please lets get back on topic...

details on this pass? tires? 60 foot? trap speed?

I would think that your setup would make anywhere from 350-400 rwhp n/a at the most I would say...but theres no way that setup can make 500 rwhp n/a which is what your claiming.

Im not trying to be a dick, just curious about the car cuase I would definately be interested in a similar setup.

 

[realitygt]

do you have cats in your x pipe? i don't see anywhere else that you could get backpressure?

i know I've heard of bbk's x pipe cause a lot of backpressure and causing pinging at high hp, but it pings along with the backpressure. not just backpressure.

maybe someone shoved a shit ton of potatos up ur tailpipe? lol

idk check your intake manifold vaccum, and report back. i'm curious

 

[justinschmidt1]

You should just run open headers.

 

[MustangMatt96GT]

You should just run open headers.

+thats what im doing this weekend!!

 

[realitygt]

i never even got to start my car up with open headers or manifolds :O

pisses me off.

 

[Willis_98GT]

i never even got to start my car up with open headers or manifolds :O

pisses me off.

you'd love it bro lol, reminds me of the time i put my hpipe on.. the left side pipe was off by like 1 1/2" so i couldn't connect the muffler so i never hooked the mufflers back up to it.. that was a fun loudass ride up to the muffler shop on open Hpipe.. got pulled over twice.

 

[Sroken Silver 5.1]

do you have cats in your x pipe? i don't see anywhere else that you could get backpressure?

i know I've heard of bbk's x pipe cause a lot of backpressure and causing pinging at high hp, but it pings along with the backpressure. not just backpressure.

maybe someone shoved a shit ton of potatos up ur tailpipe? lol

idk check your intake manifold vaccum, and report back. i'm curious

Sorry for the late reply...Yes it is a BBK XPIPE with no CATS! Not sure which headers they are but they are long tube....

 

[justinschmidt1]

your problem is your SLP1 catback.


those "mufflers" love to make that popping and cracking sound

 

[realitygt]

do you have cats in your x pipe? i don't see anywhere else that you could get backpressure?

i know I've heard of bbk's x pipe cause a lot of backpressure and causing pinging at high hp, but it pings along with the backpressure. not just backpressure.

maybe someone shoved a shit ton of potatos up ur tailpipe? lol

idk check your intake manifold vaccum, and report back. i'm curious

Sorry for the late reply...Yes it is a BBK XPIPE with no CATS! Not sure which headers they are but they are long tube....

then i'd have to say it's the bbk x pipe. there's a guy on stlmustangs who had the same problem, he got a custom x pipe made and it's fine now.

 

[dwight97]

mine pops like that when first drive it but after that it goes away