Exhaust Help

[Theninemilly]

As of right now I have CAI, Motormounts and a Unichip that I am about to install. My next purchase will happen this week and I really want to open up the exhaust flow. I have been tossing it up between the apexi N1 3" with 3" downpipe no cat. I also have been looking at the full vibrant exhaust system.

I am just curious to hear from the people who have these exhaust and what they think of them before I spend $800+ on the exhaust. Also are the Apex Downpipes still having problems with them braking?

Thank you

 

[CasopoliS]

full exhaust thread sticky somewhere

 

[CasopoliS]

http://www.msprotege.com/forum/showthread.php?t=43030

done

 

[apocman]

I thought the only true 3" turbo-back exhaust out are from ION and GHL???

Vibrants is not a true turbo back, since it bolts to the stock s-pipe...

 

[Theninemilly]

i've read the exhaust thread but I was narrowing it down between the 2 and thought some people might be able to help

 

[MrDiggler]

i've read the exhaust thread but I was narrowing it down between the 2 and thought some people might be able to help

I'm installing my Vibrant right now. I'll give you some feedback as soon as it's done. I'm also swapping the tranny, flywheel, clutch, SMIC and motor mounts, so it may be a day or two before it's back on the road.

 

[tiwing]

I have the 3" vibrant (stock downpipe). I drive a LOT on the highway... I've switched out the 3" muffler for a 3" magnaflow that's not quite straight through, sort of an S with better baffling. If you drive a lot on the highway, you might get tired of the 3" straight through drone.

If you're running less than 220whp, you also don't "need" a 3". If you don't want it to be loud, you probably only lose 1 or 2 hp by going with 2.5" mandrel.

If I were doing it again, I'd mirror the custom exhaust I put on my 323 except I'd start with 3" and downsize to 2.5" closer to the back when the exhaust is cooler and doesn't take up as much space as it needs up front. (323 is 2.5" hydraulic bend all the way back)

It would look like this:
- 3" downpipe
- 3" J or Midpipe with 1 high flow cat
- 2.5" catback with 2 inline resonators
- 2.5" axleback with not a quite straight through muffler, and a reasonable sized tip that doesn't amplify the exhaust.

 

[Theninemilly]

I have the 3" vibrant (stock downpipe). I drive a LOT on the highway... I've switched out the 3" muffler for a 3" magnaflow that's not quite straight through, sort of an S with better baffling. If you drive a lot on the highway, you might get tired of the 3" straight through drone.

If you're running less than 220whp, you also don't "need" a 3". If you don't want it to be loud, you probably only lose 1 or 2 hp by going with 2.5" mandrel.

If I were doing it again, I'd mirror the custom exhaust I put on my 323 except I'd start with 3" and downsize to 2.5" closer to the back when the exhaust is cooler and doesn't take up as much space as it needs up front. (323 is 2.5" hydraulic bend all the way back)

It would look like this:
- 3" downpipe
- 3" J or Midpipe with 1 high flow cat
- 2.5" catback with 2 inline resonators
- 2.5" axleback with not a quite straight through muffler, and a reasonable sized tip that doesn't amplify the exhaust.

thank you very much for this information. Most of my driving is done on the highway. It's about 25 miles from my work to my house. So i'm sure it will be a little annoying after awhile. I might just get the apex 2.5" all the way back or the vibrant.

 

[apocman]

you may even check your local exhuast shops and see if they will make you one for a lot less...

 

[Theninemilly]

you may even check your local exhuast shops and see if they will make you one for a lot less...

should I just get 1 from the cat back at 2.5" and then buy a downpipe? I dont plan on switching out the the s pipe.

 

[haze20]

If you really don't like the sound of the exhaust you can use the silencer to make it sound stock. I drove across country and back and the exhaust didn't bother me at all.

 

[apocman]

well there is a local shop here (real nice for an exhuast shop) and they will build and install a 3" mandrel bent exhuast with a really awesome super hi-flow cat that flows 20% better than even my racing cat I have on my ION (from what I understand) from the J-pipe back for $450 if you have your muffler already. or you can just get one from him for a little more. He will also reflange it for $20 if you ever come back with a new S&J pipe combo...

P.S. you can also port and polish your stock S-pipe...

 

[tiwing]

.. the other reason might drone more is because I have the AWR MT motor mounts from and rear - it transmits much more noise into the cabin than stock or softer mounts - you might be OK with the 3" vibrant. sorry, just thought about that...

 

[hoindawall]

i have a mam midpipe w/hiflow cat and the 2.5" apex catback. for me its too loud for daily driving so i put in a silencer and its a lot quieter on the highway.

 

[MrDiggler]

.. the other reason might drone more is because I have the AWR MT motor mounts from and rear - it transmits much more noise into the cabin than stock or softer mounts - you might be OK with the 3" vibrant. sorry, just thought about that...

Yeah, one reason I chose the Vibrant is because a bunch of peeps said it didn't drone. I guess I'll know soon. The silencer should tone it down if it does.

I had a 2.5" HKS exhaust on my 323 GTX and it droned like mad. I definitely don't want that again.

Speaking of which, tiwing, you still have yours? Mine is long gone (stolen, stripped, burned) but it's still my favorite car of all the sweet rides I've owned. I'd love to have another if I had a source for cheap replacement transmissions!

Now back to your regularly scheduled thread...

 

[RenzoMSP]

If you really don't like the sound of the exhaust you can use the silencer to make it sound stock. I drove across country and back and the exhaust didn't bother me at all.

I a couple of long road trips. The silencer does its job.

 

[tiwing]

Diggler, yeah still have it. I just got it in August, 180,000km on it, prob the most fun car I've every owned, for different reasons than the MSP is fun. Needed an exhaust so I had one custom done. no drone. It's beautiful & understated, but still growls when you're on it. Check out my website if you want to reminisce (& see what the plans for it are): http://www.kgm.tiwing.com/88maz323gtx1.htm

/threadjack

 

[tiwing]

I suspect why some guys are having trouble with bending/breaking downpipes is that the midpipe is not secured to the tranny. When I first put on my Vibrant, the bracket was there for it but the bracket to attach it wasn't moved over. I had one built so I didn't crack the exhaust manifold. If you don't have it secured there, any movement of the motor is forced to be absorbed by the flexpipe AND the downpipe/exhaust manifold, while if you have this bracket, all the movement of the exhaust and motor is forced to be absorbed by the flex pipe (where it should be). Make sure your exhaust is installed properly, with this bracket being moved over from your stock exhaust!!

 

[BradC]

I'd start with 3" and downsize to 2.5" closer to the back when the exhaust is cooler and doesn't take up as much space as it needs up front. (323 is 2.5" hydraulic bend all the way back)

I understand your thought process here, but you have it backwards. The hotter exhaust gases up front have a higher velocity, and can deal with smaller pipe (slightly). When they cool (in the back) they loose velocity and need the bigger pipe.

 

[tiwing]

I'd argue that the exhaust loses velocity BECAUSE it's in the same sized, or larger pipe and has cooled. Which means, if you're within the optimal exhast velocity range for the specific motor, then it shouldn't matter that you're decreasing pipe diameter as long as you don't force an increase in velocity (and therefore increased backpressure and decreased velocity up front)... I'd love to try it and test it - it might not be perfectly optimal, but the benefits of reduced resonance "might" outweight a (theorized) slight decrease in peak HP. I wonder what the effects on torque would be with this setup.

not sure if this is the right thread to have this conversation..... we're kind of threadjacking.