Switching side pipes to under car exhaust?

[Newsnake]

I am on the hunt for a cobra but I have small children so I don't want any snakebites for my little guys. Is changing side pipes for under car exhaust hard/expensive? Is under car exhaust more quiet on the neighbors ears?

[kayakjack]

I have a Superformance with undercar exhaust. Yes it is quieter on the neighbor's ears. Great sound. Not as loud as most sidepipes. Wasn't sure I would like this setup when I bought the car. There are still days when I wish I had pipes.

Most days I love the undercar exhaust. I am delighted with them. Good decision for me.

Jack

[Dwight]

Most Cobras you would have to repair the cutout in the body. There may be a couple of Cobra where the sidepipe leave the engine compartment under the body. I don't know of any but maybe.
If you could find a good fiberglass body man he should be able to repair and paint the area.
I would think the color and age of paint would be a factor.

Ask around. Look for shops that do Corvette body work.

The exhaust system would be easy.

Dwight

[marcalan]

You could go for a fia body style, then the side pipes are under the car more or less.

[Outwest34au]

"Most Cobras you would have to repair the cutout in the body."

I personally would leave the sidepipes on for looks and go with the underbody exhaust.

I have seen a cobra replica here recently that had the turned outlets cutoff and then pipes exiting underbody at the rear of car. Effectively using the existing sidepipes as mufflers. This won't negate the burny problem though, it is just to satisfy our registration requirements.

Mine has a full underbody system and will be hassle free in most respects, but I do hope to be able to afford decorative sidepipes down the track.

[fastraxsg]

Under car pipes really lessen's your car's ground clearance, do a thoughtful check of the areas you normally frequent for speed bumps and such before you make the change. There isn't much space to put a muffler under the car.

[marcocsx3121]

I can't comment on the difficulty of building an efficient header/collector system on a replica, but doing it on CSX3121 was a pain in the butt. Being something of a purist (even though I had a bunch of underhood stuff chromed), I resisted going to side pipes and had a header system fabbed up. It looked OK, but fitting it around the brake and clutch master cylinder mounting box was tough. In the long run, it probably wasn't a lot better than the horrendous stock, cast exhaust manifolds.

[strictlypersonl]

Originally Posted by Newsnake

I am on the hunt for a cobra but I have small children so I don't want any snakebites for my little guys. Is changing side pipes for under car exhaust hard/expensive? Is under car exhaust more quiet on the neighbors ears?

Some kits have room to fit mufflers under the floor (and pass the pipes over/under the axle), some do not, so you must check the layout of your intended kit. No matter which kit, even the best designs are pretty tight.

[ZOERA-SC7XX]

Why not use a pair of heatshields? They can be tastefully done and keep the kiddies (and your) legs safe.

[mickmate]

As pointed out what brand you have is pretty key as to how much customising of the exhaust needs to be done. Post under you manufacturers forum and see if anyone has done undercar for your breed. I like the street car under exhaust look and sound. I have made headers for original and other cars to fit them and they are tight around the steering and brakes.

[Tom Wells]

Newsnake,

Here's a photo of a car designed from the beginning for an undercar exhaust:


Note the headers designed for this application and the notch in the outrigger support to allow the pipe to be moved upward an inch or so.

I've driven this car 27K miles with this system and have had to rebuild it twice, completely, including the headers which were poorly made at first. The latest system looks very much the same - the workmanship is far better - and has lasted more than 15K miles just fine.

Here's a shot of the whole car:


The exhaust is not the lowest part of the car. The bellhousing and deep automatic trans pan share that honor.

Unless you have good other reasons, try to find a car or kit that is set up for this type of exhaust from the beginning, particularly if you intend to put some significant miles on it. If it's just going to be a garage or trailer queen, almost any setup would be OK.

There's no chance for "snakebite" with this setup. The noise level is still, um, significant. If you can run the exhaust out to the rear of the car, it will be quieter. Alas, on this car there wasn't enough space to get by the Jag rear.

So you pays your money and takes your choice!

Enjoy,

Tom

[ekrupa2]

Wonder if these might be a solution for you...

http://mastertouch327.com/2.html

[Silverback51]

I would go with the side pipes and teach the kids to respect the pipes. No different than other things they need to learn.

But that's me.

[Tom Wells]

ekrupa2,

What a nifty piece! Looks like a decent option.

Interesting web site, too.

Wonder what a "Vitussus" is???? I Googled, DogPiled and Wikipedia'd without finding it...

Tom

[kayakjack]

Originally Posted by Tom Wells

Newsnake,

Unless you have good other reasons, try to find a car or kit that is set up for this type of exhaust from the beginning, particularly if you intend to put some significant miles on it. If it's just going to be a garage or trailer queen, almost any setup would be OK.

Tom

Makes sense. I know Superformance makes one with undercar exhaust (I have one). Not sure which other manufacturers offer this.

Jack

[ZOERA-SC7XX]

Also would make for HOT floorboards.

[Jim Doak]

I have an FFR replica and changed from side pipes to an under car exhaust system in 2006 for the reasons you mentioned: it is safer for my two girls - who were 7 and 3 at the time - and is also much quieter. I also like the look.

It was too big of job for me to do so I farmed it out to a local shop - Dr. Gas. I have a solid rear axle and they placed the counter-flow muffler tucked up behind the differential. They also notched my rear cross member and used ovalized tubing to maximize ground clearance.

[kayakjack]

Originally Posted by ZOERA-SC7XX

Also would make for HOT floorboards.

All the more reason to get a car that has been engineered for this setup. I have no floorboard heat.

Does Factory Five have an undercar option? Other than Superformance, who does?

Somebody mentioned getting a 289/slabside. That would be one way to get the pipes off the sides.

Are you trying to make a car or buy a car?

Jack

[mdross1]

When building my car had the frame clearanced just for under car exhaust,making the bell housing flange the lowest point under the car.Had Stainless chambered mufflers custom made the car sounds and performs great.The Cobra has excellent lines,no matter where the exhaust exits.Undercar exhaust makes getting in and out of the car a non issue,plus you can drive the car hard all day and not have a headache without a helmet.

[Three Peaks]

If you're buying a completed/used car, look for a street car with the undercar exhaust already installed. There are a few of them available for sale if you look.

However, if you are interested in building a car with undercar exhaust you'll need to look for a kit or manufacturer with a chassis that allows for a little "customization". The FFR and several other manufacturers offer the option of cutting the holes for the sidepipes, so you can start out with a body without the cut outs.
Several manufacturers have out riggers that can easily be modified as the car above to accomodate pipes/mufflers in the space under the seats. Ovalized pipe can help in this area to minimize clearance issues.
The cars with floor mount pedal box will be most difficult to deal with but not impossible. Trying to get around the pedal box, master cylinders, clutch slave cylinder and all of the other pieces under the car can be difficult but not impossible. It seems a car with the hanging type pedal box would be best suited to fitting the undercar exhaust on the driver's side.
Going over the rear axles is problematic in these cars. There is barely enough room for the axles and suspension to work properly, much less add exhaust pipe to the equation. This is obviously why most guys exit the pipes just in front of the tires. I've wondered if it would be worthwhile to build a "false trunk frame" inside the existing frame of cars with a trunk frame and aluminum trunk sides/bottom. You would lose a bit of trunk space, but you could gain a channel on both sides of the trunk to install the exhaust pipe to avoid the axle and still have it open to air on the outside for cooling purposes. This would also give you a channel to go over the gas tank and exit behind the gas tank without interfering with the suspension and/or roll bar mounts.

Of course, this option may not work well with cars with a fiberglass tub for the driver compartment or trunk.

Bob