3" SS exh. system on 89 CSX

[dgrun]

Hi,

Please don't jump all over me about this, but I have some questions about the 3" SS full system from forward motion that is currently installed on my 89 CSX-VNT (no other engine mods at this point).

a little history first. I got this system a couple/three years ago when I needed to replace the stock cat. I had always thought of upgrading to a 2.5 SS forward motion system, but they no longer make them. so, I went to the 3 inch system.

1. it feels like (I am not sure) it has lost a little pop off the line (this could be due to the age of the car, and almost 130,000 miles on the engine - rebuilt head and new turbo a few years ago als.) could this be the case? why? If I plan to rebuild/upgrade engine, should I keep this system? when accelerating from a standstill, it just seems like it makes all this noise and doesn't go all that fast. (it sure seems like it used to accelerate better).

2. this system is too loud for me. when I got it, the guys at forward motion said "its not that loud, esp. for a 3" system". after it was installed, even my mech. said "its pretty darn loud". I have contacted fm about this, and they recommended perhaps a 2.5 inch muffler to quiet it down a bit. they also said they never heard that complaint before. I guess most people like it loud, not me. I am 51 yrs old now and have had the car since brand new. I liked the quietness of the original exhaust but wanted a bit more power. any suggestions?

3. how about getting a local guy to make a custom 2.5 inch system like i originally wanted? is this a big problem?

thanks for any comments/ideas/suggestions. the car is currently being rebuilt and one thing I am going for, besides upgraded performance w/o changing the look of the car is a really quiet car. I've already applied QuietCar (www.quietcar.net) to the outside and inside of the car. the exhaust is still darn loud.

DG

[crazymadbastard]

At 130k, it should still have plenty of pep, go check the cam timing and engine timing. Are you running a cat? if not put a 3" cat in there.

Another though I have is that going from the 2.5 downpipe to a 3" might be like having a megaphone- just a theory... Might be good to go 3 inch from the swingvalve back.

Look into a warlock muffler from Summit, this has removeable plug that will be like no muffler if you ever feel the need, yet its quiet when plugged.

[dgrun]

cmd,

yes, it has a 3" cat. thanks for your other suggestions.

DG

[thelostartof]

when was the last time you did a tune up? plugs and wires can change the way a car acts. cleaning out the PCV system can also help along w/ new filters where they need to be.

going to a smaller system might rob a little power from the 3" system you have but prob not enough for it to matter for you to get a nice quiet system. if anything keep the 3" downpipe and cat and go 2.5 from the back of the cat as that will keep most of the power of the 3" system

either way give the car a good tune up. maybe even a compression test to either have an idea on carbon build up so you could seafoam it(top end cleaning) or just check the shape of the rings from age

[tryingbe]

You have a 3 inch muffler, right?

[boostboy]

Im guessing the problem lies within the 3'' system, VNT cars like a little backpressure unlike most other turbo's. Id think a 2.5'' system would be the way to go, with a hi flow cat and 2.5 inch muffler. That should retain close to stock sound, but give you what you are looking for. As well, I also agree with a full tune up of the motor.

[dgrun]

tryingbe,
yes, I have a 3" muffler. Its an ATR Pit Bull or something. its stainless also, but I'm guessing that it doesn't have much sound absorption material in it.

************,

your idea sounds the most sensible to me at the moment. thanks. could cost a bit, so maybe i'll just try a different muffler for now.

boostboy,

that's kind of what I was thinking, but that could really be expensive, as I intend to always have an all stainless system on the thing as that is what it came with, although I am going to price a new system and see what's involved.
DG

[crazymadbastard]

Here is a link that you can visit with muffler tests:

http://home.earthlink.net/~tmahon281/image.html

hope it helps a bit more.

Winston

[puppet]

Is 3" exhaust needed?
I'll direct you to this post regarding the 2-1/2" vs 3" debate.

[Ondonti]

Grab a stainless 3" Round race series ultraflow (NOT THE bullet).

splice it into the middle of your exhaust system. Wont hurt flow at all......just add a few pounds. Should make a huge difference.

[puppet]

He won't be able to splice that 6" dia monster into the middle of the exhaust. Won't fit in "mid-tunnel" of my Daytona anyway.
Only two places that'll fit good ... where the CAT was/is (tight fit but you can do'er) or, in the very back.

[DirectConnection]

I had a 3" mandrel JRB systems with 3" Ultraflow and NO cat on my '90 VNT Shadow and the last thing it did was feel laggy or sluggish down low. Maybe they left a couple rags inside by accident on your car.

What ar you doing for a calibration? A stock VNT cal would be going nuts and shutting down everytime you hit the gas. My cal worked awesome.

[ecs]

What kind of muffler do you have on it again? I saw that you said you have a muffler, but is it a straight thru? Straight thru meaning if you look in either end, you can see all the way to the other end. If its chambered then you may have just gotten a loud muffler. I've had good results using cherrybomb turbo mufflers (NOT THE GLASSPACKS) to quiet down people's exhausts. If it's still too loud for you try adding a resonator somewhere in the system. Preferably between the cat and the muffler. Also, where is the exhaust exiting? Make sure it's exiting well behind the car for minimum interior noise. The closer to the front the exhaust is, the louder it will be inside the car.

Also, is it welded together? If you clamp exhausts together they will DEFINATELY be louder than if it would've been welded together. Excuse me if the exhaust system is one piece, i never looked into the FM exhaust system for these motors.

If all of the above check out, then it's most definately the 3" exhaust. When I put a bigger pipe on my 3.3 dynasty it definately got louder. I converted the over the axle pipe from 1 7/8 to 2" and for some reason the exhaust got so much louder. I can only imagine what it would sound like with a 3" pipe.

And upgrading to a bigger pipe usually moves your torque band into the upper RPM range, although this may not always be true with a turbo, it is a possibility.

[dgrun]

updated reply:

the muffler is a straight thru muffler.

the exhaust exits right after the muffler. there is a short pipe with a turned down opening, its behind the rear valence, not the kind of pipe that was on there originally that exits below the rear valence.

I had the exhaust pipe that was originally clamped to the back of the cat welded all around. that quieted it down a bit, esp. as the pipe kept pulling out of the cat when it was clamped.

still too loud.

I would like to try the resonator between cat and muffler, but am afraid that that would be a no go back modification if it didn't work.

the next thing I am going to try is to get someone to make me a longer pipe to exit down lower after the muffler.

I appreciate all the comments so far.

DG

[crazymadbastard]

Hey Dg,

I bumped into these and maybe they might help.

http://www.jegs.com/webapp/wcs/store...muffler+insert