Factory rear mufflers? HP support?

ricardoa1

Registered User
How much do the factory rear mufflers support for HP. I know the resonator and cats are the problem. But I hear that the factory mufflers are good flowing units. How much HP does it support?
 
i called ford and there answer was be like everyone else and get flowmaster. so in short they didnt know
 
I was close to 300rwhp with the stock ones before, unlike "everyone" else :rolleyes:, I installed all magnaflow.

The older style pipes where 2-1/4" pipe going into them, where the newer ones used a 2" pipe going in.

Fraser
 
i have full 3" exhaust on my black 90, with a 12inch summit glasspack and a summit turbo muffler i can hold her steady at 100 on the interstate and you can't even hear the engine.

needless to say its probably just as quiet as stock normally driving
however, when at WOT anything over 3500 makes it sound like a bees nest but tolerable

on my red 90 i have a dynomax muffler that sounds sweet, it doesn't buzz at high rpms either like my black 90 but i believe thats due to it being more restricted (crush bent 3" pipes and still has both dp cats)
 
Guys, he's not asking what muffler to use... he's asking how well the stock mufflers will perform...

Ricardo, whats your power goal for that car?

Fraser
 
I don't mean to squeeze in, but I'm curious to the same thing.

My intended HP is fairly low - 240-250RWHP at the very most. I'll be doing new high flow cats, probably a Magnaflow resonator, and was hoping to just reuse the stock mufflers.

-Melon
 
Rico..Its probably the pipes moreso then the mufflers themselves that are restrictive. ..But who would go through the cost and keep the stock mufflers.......I believe Bill or Charles did testing back in the day that rear backpressure at different points in the factory system in various forms of modifications...Just check
 
I don't mean to squeeze in, but I'm curious to the same thing.

My intended HP is fairly low - 240-250RWHP at the very most. I'll be doing new high flow cats, probably a Magnaflow resonator, and was hoping to just reuse the stock mufflers.

-Melon

In your case, the stock mufflers will be more than adequate, but its the pipes leading to them that could be an issue. If its the older style mufflers, they used a 2-1/4" pipe to lead into them, while the newer had 2".

Fraser
 
In your case, the stock mufflers will be more than adequate, but its the pipes leading to them that could be an issue. If its the older style mufflers, they used a 2-1/4" pipe to lead into them, while the newer had 2".

Fraser

what is the single midpipe?
 
The older style used a 2-1/2" pipe I think, while the newer used a 2-1/4".

The older style actually flowed better than the newer style.

Fraser
 
The older style used a 2-1/2" pipe I think, while the newer used a 2-1/4".

The older style actually flowed better than the newer style.

Fraser


Not so sure. The older style wrapped around the gastank while the newer style had a more direct pathway. The crossection at the bends around the tank I believe were very small and compression bent
 
I know there is a exhaust thread where DD talked about how good the exhaust is behind the resonator, but I have yet to find it.


Not so sure. The older style wrapped around the gastank while the newer style had a more direct pathway. The crossection at the bends around the tank I believe were very small and compression bent

Does it really matter? I know both of us have a larger mid-pipe but Neibert was making 425 and I'm making 350 with a old style gas tank.

Were there compression bends in the stock y-pipe? I do see where Ford put a "dent" in the exhaust for a support bracket. When I had my resonator replaced they removed that "dent".

Pictures from my totally stock 1990 SC:

attachment.php


attachment.php
 
I know there is a exhaust thread where DD talked about how good the exhaust is behind the resonator, but I have yet to find it.




Does it really matter? I know both of us have a larger mid-pipe but Neibert was making 425 and I'm making 350 with a old style gas tank.

Were there compression bends in the stock y-pipe? I do see where Ford put a "dent" in the exhaust for a support bracket. When I had my resonator replaced they removed that "dent".

Pictures from my totally stock 1990 SC:

attachment.php


attachment.php

The post you are reffering to is not how good the factory exhaust is but how bad the cat back isnt (based on relatively mild combinations). The picture you show has compression bends at every turn and even some just for the heck of it. Maybe they arent as wild a crunch as you get from your local Joe muffler shop but they are most definitely there

Dave N used his old tank when he did his exhaust but that was not optimal and cant even be compared as it was far from stock.

By far the resonator and factory cats are the most restrictive portion of the exhaust. But at some point each and every factory peice will eventually become a restriction. You may be leaving something on the table by using factory mufflers or pipes. How much?..WHo knows..As far as backpressure. You can measure before and after each componant of your exhaust
 
Thank you for the pics,

So an early system is 2 1/2 and mufflers are 2 1/4 Mufflers. I dont want to redo the gas tank. Not worth my trouble. I figure a Y pipe from aftermarket cats to the support area cant be much more then 200bux that that what I want i dont want to spend much on it. I have a set of Flowmaster Mufflers from a Tbird Kit that i hacked I dont remember what that kit was but its the muffler that has a side entry. I could use those but then I would have to buy a resonator ect. I dont want to spend the money on parts that only offer marginal improvements. The most bang for the buck parts will be what will go on the car.
 
I know there is a exhaust thread where DD talked about how good the exhaust is behind the resonator, but I have yet to find it.




Does it really matter? I know both of us have a larger mid-pipe but Neibert was making 425 and I'm making 350 with a old style gas tank.

Were there compression bends in the stock y-pipe? I do see where Ford put a "dent" in the exhaust for a support bracket. When I had my resonator replaced they removed that "dent".

Pictures from my totally stock 1990 SC:

attachment.php


attachment.php

if you have an impact you might want to replace your front seal very very soon. thats a pretty bad leak by the looks of it :eek:
 
Back
Top