Questions about Flowmaster 70 Series

[James909]

I searched but didn't find the answers I was looking for so here it goes. I have a '92 EX that currently has a stock exhaust set up. Well the from the muffler back has been replaced but with stockish parts and 2.25" tubing. I was thinking about cutting out the muffler and replacing it with a Flowmaster 70 series. What do you guys think about this set up? I would be leaving the 2.25" piping and resonator. I don't want the truck to be loud or ricey sounding. In fact it would be fine even if it wasn't any louder than stock, I just want a nicer tone. I'm also hoping to improve mpg and any extra power would be appreciated too. Is this worth doing? Or is it not a good idea? The main problem is that the smallest single in/out 70 series has 2.5" openings. Would it be OK to use a 2.25" to 2.5" adapter on both ends of the muffler? Thanks for any help or opinions you guys offer.
-James

 

[robmurt04]

I searched but didn't find the answers I was looking for so here it goes. I have a '92 EX that currently has a stock exhaust set up. Well the from the muffler back has been replaced but with stockish parts and 2.25" tubing. I was thinking about cutting out the muffler and replacing it with a Flowmaster 70 series. What do you guys think about this set up? I would be leaving the 2.25" piping and resonator. I don't want the truck to be loud or ricey sounding. In fact it would be fine even if it wasn't any louder than stock, I just want a nicer tone. I'm also hoping to improve mpg and any extra power would be appreciated too. Is this worth doing? Or is it not a good idea? The main problem is that the smallest single in/out 70 series has 2.5" openings. Would it be OK to use a 2.25" to 2.5" adapter on both ends of the muffler? Thanks for any help or opinions you guys offer.
-James

Leaving it stock won't net you much gain in MPG. What I'd do is do the 2.25 to 2.5 adapter for the front but run 2.5" piping out. It'll give you a little deeper & better tone. It should also give you a slight increase in mpg and throttle response.

 

[aldive]

I have a Flow 70 and its not loud at all ( thank God ) and does not resonate in the cab.

I think you are just peeing into the wind unless you replace the pipe ( from the cat back ) with 2 1/2" pipe.

Good luck ...

 

[James909]

Thanks for the responses guys. I'll see if I can see if I can swing by an exhaust shop tomorrow to see what they would charge to replace the piping. Should I leave the resonator in place, or just run pipe back from the muffler?

 

[aldive]

Should I leave the resonator in place, or just run pipe back from the muffler?

I removed mine years ago when I did the cat back.

 

[James909]

OK, thanks.

 

[CDW6212R]

Ditto, with the 70 series being relatively quiet, I'd leave out the resonator also. Do the 2.5" tailpipe, and adapter in front. What are prices now, I recall finding $150 typical last Summer?

 

[James909]

Ditto, with the 70 series being relatively quiet, I'd leave out the resonator also. Do the 2.5" tailpipe, and adapter in front. What are prices now, I recall finding $150 typical last Summer?

The price seems to be the main downside to this muffler. The cheapest I've found is $133 from Summit plus shipping. I haven't gotten an estimate from the exhaust shop yet because they were closed today. Does anyone know of a place where I can buy a prebent tailpipe for the Ex? I found one but it had 2.25" tubing. If I can find one a may put the exhaust together myself using clamps. Unfortunately this is quickly becoming expensive enough that I am considering just leaving the exhaust. Especially since the exhaust is still in good shape and is relatively new. But we'll see what the shop says. I was hoping to just switch the muffler and be done.

A few more questions that I thought of. Is mandrel bent tubing really important? Or would regular bends be fine? Also are the recommendations that you guys are making for the 2.5" tubing aiming towards making the best sound? Because based on the information I've found from a performance aspect it's best to go down in exhaust pipe size the further from the engine you get. This is to keep the exhaust gas velocity up as the exhaust cools.

Thanks,
-James

 

[CDW6212R]

The mandrel bent 2.25" tailpipe would flow about the same as a crush bent 2.5" pipe. For the stock engine the 2.5" tailpipe would not gain a noticeable difference. A larger outlet tip size tends to be louder than a smaller size. Note how the huge tips sound on the tiny imports you have heard.

For my 4.0 truck I chose the one muffler(of my choice) that had a pair of 2.25" inlets. The outlet is 3", and I had a 2.5" tailpipe bent(crushed) with a 2.5" resonator. For near stock go with the muffler of your choice, and do what you have to past it.

FYI, for power gains do not shy away from larger pipes. The idea of back pressure being good or maximizing velocity, that is all crap/myth/hogwash. If you have a strong Mustang V8 with decent modifications, running dual 2.5" pipes is stupid if you can manage to get 3" pipes instead. After proper tuning, the bigger pipes will always result in faster times. Regards,