V6 exhaust issues

[miket]

I've gone out and bought the dynomax mufflers, tubing from NAPA and a selection of bends from Canadian tire.

But still undecided as to the best routing for the exhaust. The first prerequsite is that I want dual exhaust. And that's where the fun begins.

I had thought that the mufflers on my Tiger were behind the differential, but that was a long time ago, and it seems I was wrong. Stll I've tried various combinations and it seems to me that the best fit would be to have the mufflers behind the diff, with a various bend going over it.

Is it me, or does the Alpine sit higher than the Tiger. This is part of the problem. The fact that the exhaust would have to come down more to get under the diff, then back up to pass through the frame.

The other issue is the battery box. I guess it's a gonner. I have a very small battery in my MGA (it only does summer starts) and maybe I could save a part of the battery box and use the smaller battery.

Well I guess I've talked myself into placing the mufflers behind the diff with the tube running over it. And take away some or all of the battery box.

Gotta drill that 3" hole in the frame. That should be fun.

Just wondering what your conclusion was.

Mike

 

[V6 JOSE]

I've gone out and bought the dynomax mufflers, tubing from NAPA and a selection of bends from Canadian tire.

But still undecided as to the best routing for the exhaust. The first prerequsite is that I want dual exhaust. And that's where the fun begins.

I had thought that the mufflers on my Tiger were behind the differential, but that was a long time ago, and it seems I was wrong. Stll I've tried various combinations and it seems to me that the best fit would be to have the mufflers behind the diff, with a various bend going over it.

Is it me, or does the Alpine sit higher than the Tiger. This is part of the problem. The fact that the exhaust would have to come down more to get under the diff, then back up to pass through the frame.

The other issue is the battery box. I guess it's a gonner. I have a very small battery in my MGA (it only does summer starts) and maybe I could save a part of the battery box and use the smaller battery.

Well I guess I've talked myself into placing the mufflers behind the diff with the tube running over it. And take away some or all of the battery box.

Gotta drill that 3" hole in the frame. That should be fun.

Just wondering what your conclusion was.

Mike

Hi Mike,

Since you plan on putting a 3"pipe through the cruciform, it should be easy to mount the rest of the system. The Tigers had the mufflers in front of the differential, but ran the pipes under the rear end. You can place the mufflers under the trunk floor, with the pipes going under the rear end. Several of my customers have done it this way and have no problems with dragging any of the exhaust system when going over speed bumps.

I recommend having the tips of the pipes, extend past the bumper by about 1.5". If they end before the bumper, the exhaust gases will be sucked into the trunk and then the cabin.

Jose

 

[miket]

Thanks, Jose,

I'll try that setup. If I run the pipes under the differential, then I won't have to chop the battery box.

Mike

 

[V_Mad]

Thanks, Jose,

I'll try that setup. If I run the pipes under the differential, then I won't have to chop the battery box.

Mike

I ran my pipes the same as the Tiger (I used an ex Tiger exhaust system) but I did chop the battery box by about an inch to get the muffler in - still enough room for the battery.

 

[Alpine 1789]

I did chop the battery box by about an inch to get the muffler in - still enough room for the battery.

What size battery are you using?

 

[miket]

Jim,

I plan to get a new battery, as I don't know how old this one is.

I'll get the smallest possible. The one in my MGA is about 8 1/2" wide. I used it in my Blazer when that battery died and it was fine.

The smaller battery will allow me to take a few inched off the battery box.

I won't be doing cold weather starts, so no chance that the battery power will be reduced by the cold.

Mike

 

[V6 JOSE]

Jim,

I plan to get a new battery, as I don't know how old this one is.

I'll get the smallest possible. The one in my MGA is about 8 1/2" wide. I used it in my Blazer when that battery died and it was fine.

The smaller battery will allow me to take a few inched off the battery box.

I won't be doing cold weather starts, so no chance that the battery power will be reduced by the cold.

Mike

Mike,

You will find that the little V6 loves to start, so you don't need to keep on cranking it over, like some engines do. I would suggest getting one of the gel cell batterys, because they are smaller and can be mounted just about anywhere.

Jose

 

[miket]

Jose,

Good idea, I'll have a look for the gel batteries.

V-Mad, I put on my work dud's at noon, and tried again to test for the fit under the floor. The Dynomax(thrush) mufflers that I bought are fairly high so ground cleance could be an issue. At least if they are behind the differential it would hopefully take the hit first.

What I don't like is the fact that the mufflers are in view, from the rear.

The next best route is the cherry bombs, but I understand that they don't give a very nice sound.

Or maybe no mufflers??

 

[V6 JOSE]

Jose,

Good idea, I'll have a look for the gel batteries.

V-Mad, I put on my work dud's at noon, and tried again to test for the fit under the floor. The Dynomax(thrush) mufflers that I bought are fairly high so ground cleance could be an issue. At least if they are behind the differential it would hopefully take the hit first.

What I don't like is the fact that the mufflers are in view, from the rear.

The next best route is the cherry bombs, but I understand that they don't give a very nice sound.

Or maybe no mufflers??

I think no muflers would be prferable to glass packs. The glas packs give it a very loud bark, so will attract attention you don't really want. If you paint the mufflers black, they almost disappear from view. Even though the mufflers may be big, if you place them under the trunk they will not drag on anything. I had large turbo mufflers on my turbocharged Alpine, and never scraped anything.

Jose

 

[miket]

Jose,

I hadn't read this before I went out this evening.

I took another crack at placing the muffler ahead of the diff. It seemed to work.

I used two 20 degree bends just after the diff to get under it and up again.

But I had thought of painting the mufflers black. And now that you have mentioned it, I'm going to try that again. Under the trunk the mufflers will be higher then if they were forward. And having the rear wheels ahead of them helps to insure they rid up and over bumps.

Thanks for the advise.

Mike

 

[miket]

Here is a picture of a Tiger setup. The mufflers are ahead of the diff and quite low.

Two differences I see with the Alpine. One the battery box is an issue on the right side, and two, the rear crossmember is notched and the pass thru is far from the center.

On the Alpine the pass thru is very close to the drive shaft, so the mufflers have to be turned over so that the offset is closer to the center. then two 45 degree bends can be used to get the the passage. the two 45s again to align with the manifold.

I'm still considering having the mufflers behind the diff. Then I won't have to chop the battery box. As well the mufflers will be a bit higher.

Next week I have to attempt to cut the other passage. This should be fun.

 

[chris]

If any one has photo's of the under side of an Alpine with the mufflers tips ending in front of the rear tires, please post them. I like the idea of running them to the back like in Miket photo's, but I don't think I'm ready to cut into the frame yet.

 

[miket]

Well, I've pretty much decided to have the mufflers ahead of the diff, and below the rear shelf. And I'll pass the exhaust pipe under the diff as was done with the Tiger

This looks a lot cleaner from the back, and I won't need a heat shield. The bends are a little easier too, then going over the diff.

One question remains, and that is, how much clearance is needed between the exhaust and the diff?

Mike

 

[Bill Blue]

Has anyone tried a pair of glass packs on each pipe? I used this years ago on a Pinto 2.0. They don't take up much space and sound pretty good. Not loud. Several people commented it sounded like a sports car should.

Bill