Review my exhaust system

[boise-nic]

I called muffler shops around the area and decided paying $400 for a press bent 2.5" exhaust wasen't what I wanted. So I picked up everything I needed to build it myself. This is the first exhaust I've built and I have some questions to see if I am doing it right. Here's some pics, haven't picked out the muffler yet but everyone I've talked to think flowmasters sounds great on 4g's. Tell me what you guys think sound good on a 4g. Anyways, here's some pics...




Made my o2 a while back. I would think one would want to step it up to a full 3" as soon as possible. I'd like to cut it just after where the two come together and weld a 3" adapter to it. This would flow fantastic but my clearance gets pretty close. This pic is looking up into the turbo from the ground (where the downtube to o2 housing is located. The glove isw just holding the adapter in place until I weld it together). I'd estimate I have about an inch between the pipe and the frame rail.



Problem is, I have no idea how much it is going to flex under power on the stock mighty max mounts. I could always put a chain on the engine if it does rub. Does anyone know how much it would flex? I don't plan on making more than 300-340 hp max.

Once the pipe starts to run horizantal under the truck, I plan on having both cat and muffler flanged. I figured it would be nice to swap out parts depending on what I am doing. Road trip, nice and quiet with cat and muffler on, at the track, ditch the cat and/or muffler all together.

It looks like I can use the stock routing location. Which is good and bad. The good is there is an existing heat shield to use, the bad is with a 3" exhaust, clearance is pretty close...



Going for the cheap and easy route, what do you guys think of a simple side exit right in front of the passenger side wheel? No shiny exhaust tip or anything, just a 3" pipe. I'll probably paint it with some high heat black paint. The noise should seem quieter from the drivers seat, sucks to be in the right lane though

I'm thinking something like this...




a better pic



Anyways, I just wanted some constructive advice because I'm by no means know what I'm doing building an exhaust system.
Still have some Q's like:

Do I need a resonator?
What about a flex pipe?
Should I heat wrap the exhaust at all?

Cool thanks!

[shroder15]

It really depends on what you want. If the quieter you want your exhaust will depending on what size, if any, resonator you want. Also, getting a TRUE high flow cat can also help decrease the rasp you may hear from your exhaust without one. As far as heat wrap goes, the hotter you can keep your exhaust gasses, the faster they leave the system. The benefits of this should be self explainatory . As far as the flex pipe goes, yes, you will need one. Without it the solid exhaust pipe is mounted to a solid turbo. Everything is fairly rigid. Dont risk your exhaust/manifold/turbo by avoiding the flex pipe. it doesn't have to be huge, but they are on exhaust systems for a reason...unless you have solid mounts all the way around. Then no, you wont need one Hope it helps!

[boise-nic]

It really depends on what you want. If the quieter you want your exhaust will depending on what size, if any, resonator you want. Also, getting a TRUE high flow cat can also help decrease the rasp you may hear from your exhaust without one. As far as heat wrap goes, the hotter you can keep your exhaust gasses, the faster they leave the system. The benefits of this should be self explainatory . As far as the flex pipe goes, yes, you will need one. Without it the solid exhaust pipe is mounted to a solid turbo. Everything is fairly rigid. Dont risk your exhaust/manifold/turbo by avoiding the flex pipe. it doesn't have to be huge, but they are on exhaust systems for a reason...unless you have solid mounts all the way around. Then no, you wont need one Hope it helps!

Ok that helps me out. So exhaust wrap is a go. Probably need to pick up a resonator pipe. Can anyone explain the difference between a resonator (basically an expanded section of pipe) and one of those cherry bomb straight thru 'mufflers'? Seems like they would accomplish the same goal. I plan on using the stock hanger locations and reusing the rubber mounts. I think rigidly mounting the system would resonate the sound into the frame and cab more instead of being mounting on the rubber. I'd rather have it too quiet. If it ends up being quiet, I have the luxury of swapping the cat for a straight pipe instead of it being too loud all the time. I'll plan on ordering the flex pipe, resonator, and muffler. Muffler will probably be a borla or mangaflow. I had a borla before and it had a nice sound.

[boise-nic]

More about the flex connector...

I know most transversely mounted engines must have them because of the engine rotation. When the enine is configured longitudinally (like for RWD), the exhaust rotates more or less axially which would be easier on the system from a stress point of view. I still plan on using a flex section but I've seen many hotrods (mostly v8's) without any sort of a flex section. It's just solid all the way up to the exhaust flange. So that made me question myself a bit on needing it.

[Verdad]

i know 240's(sr20det) do not use flex pipes in the exhaust. i believe typically you'll start to see more flex pipes in exhaust when you are dealing with tubular manifold to help alleviate stress and additional weight on an already weak (relatively speaking) point.

that being said im still going to slap a small 8" or so piece in my exhaust. between my master fabbed motor and tranny mounts and the amount of abuse id like to toss at the truck, i could probably use the slop...

[77amc]

Pretty decent weld job there.. Stainless or mild?

I just finished my system on my 88 max this last week. I have a 2.6 in there with headers, cam, weber yadda yadda and went with 2.5 pipe to a 10"L flex then a 2'L body of a 'glasspack' style back out. BUT i went over the axle, added a turbo muffler and turned out after it to the pass side. (I have a longbed) and it's MUCH quieter than I thought.. I didn't want to be loud this time around. PM me your email for pics

You can use a glasspack style as a resonator. It just depends on if you have the 'louvered'-(sticks down into the airstream) or 'perforated'-(just the little holes in the walls) to the extent of 'noise' you want or not.

Since you have your turn-down close to the cab, you may want to extend it out some so it will blow out from under the bed and not get trapped under for you to breath it in. Just my .02 on that.

Looks good!
Errol