This is an option I've begun to consider on my build because: (1) I sort of like the look, (2) no burns, and (3) I understand there is more flexibility for mufflers/sound/restriction.
Does anyone have experience with this, the pros/cons, and if they would do it again? Any other opinions appreciated as well. Thanks!
Cobra Make, Engine: E-M / Power Performance / 521 stroker / Holley HP EFI
Posts: 1,935
Not Ranked
Lippy,
I have'em and I love'em. The only snakebite I ever got was while working on another Cobra guy's car...
Here's a shot of the passenger side with the body off:
You can see the notch in the front outrigger support that E-M put there to allow some ground clearance.
And here's the finished product:
Spintech made the mufflers for me. Their stock ones proved a little too wide and made one of the world's loudest rattles. After they made some for me about 3/4" narrower, they've been on there ever since. They are not SS so they are coated.
I have SS headers and pipes. This was another series of learning experiences, as the routing and fit of the pipes needs to be done correctly. If they're hanging down a bit too low, well, let's just say it makes a noise that's a lot louder than a rattle!
The pipes are 3" all the way. If you have a smaller engine (mine's a 521) you could likely use 2-1/2" and not eat too much hp.
There's a standard rubber hanger (sort of elongated O-shaped) just before the exit bend, holding onto the the pipe using a piece of 3/8" rod welded onto the pipe, and a similar hanger under the frame.
I would have taken them out to the back bumper to make it quieter on 400-500 mile days, but there wasn't any space for the tailpipes.
Spintech made the mufflers for me. Their stock ones proved a little too wide and made one of the world's loudest rattles. After they made some for me about 3/4" narrower, they've been on there ever since. They are not SS so they are coated.
I have SS headers and pipes. This was another series of learning experiences, as the routing and fit of the pipes needs to be done correctly. If they're hanging down a bit too low, well, let's just say it makes a noise that's a lot louder than a rattle!
The pipes are 3" all the way. If you have a smaller engine (mine's a 521) you could likely use 2-1/2" and not eat too much hp.
There's a standard rubber hanger (sort of elongated O-shaped) just before the exit bend, holding onto the the pipe using a piece of 3/8" rod welded onto the pipe, and a similar hanger under the frame.
I would have taken them out to the back bumper to make it quieter on 400-500 mile days, but there wasn't any space for the tailpipes.
Cobra Make, Engine: ERA Street Roadster #782 with 459 cu in FE KC engine, toploader, 3.31
Posts: 4,533
Not Ranked
Quote:
Originally Posted by Tom Wells
Lippy,
I have'em and I love'em. The only snakebite I ever got was while working on another Cobra guy's car...
Here's a shot of the passenger side with the body off:
You can see the notch in the front outrigger support that E-M put there to allow some ground clearance.
And here's the finished product:
Spintech made the mufflers for me. Their stock ones proved a little too wide and made one of the world's loudest rattles. After they made some for me about 3/4" narrower, they've been on there ever since. They are not SS so they are coated.
I have SS headers and pipes. This was another series of learning experiences, as the routing and fit of the pipes needs to be done correctly. If they're hanging down a bit too low, well, let's just say it makes a noise that's a lot louder than a rattle!
The pipes are 3" all the way. If you have a smaller engine (mine's a 521) you could likely use 2-1/2" and not eat too much hp.
There's a standard rubber hanger (sort of elongated O-shaped) just before the exit bend, holding onto the the pipe using a piece of 3/8" rod welded onto the pipe, and a similar hanger under the frame.
I would have taken them out to the back bumper to make it quieter on 400-500 mile days, but there wasn't any space for the tailpipes.
Enjoy,
Tom
How do the spintek mufflers sound on your car? I've heard they are pretty loud. I have 2-1/2 inch ones mounted on my ERA with 2-1/2 inch pipes all the way out the back end, but I'm some ways off in my build from being ready to fire up the motor.
Cobra Make, Engine: ERA Street Roadster #782 with 459 cu in FE KC engine, toploader, 3.31
Posts: 4,533
Not Ranked
Wolf K and TKB289
Did either of you have any problem with the passenger side ERA collector placing the muffler a little too far to the outside to where it interfered with the body rocker area? I had to take mine down to an exhaust shop and have a 2 degree bend put in it to center the muffler in the proper area for clearance. I hate having that slight kink in it but it will only be visible from underneath. It looked to me like the shop they have fabbing up the exhaust headers and collectors isn't allowing for the 1 inch offset of the motor to the passenger side. Or maybe it was something just unique to mine.
Did either of you have any problem with the passenger side ERA collector placing the muffler a little too far to the outside to where it interfered with the body rocker area? I had to take mine down to an exhaust shop and have a 2 degree bend put in it to center the muffler in the proper area for clearance. I hate having that slight kink in it but it will only be visible from underneath. It looked to me like the shop they have fabbing up the exhaust headers and collectors isn't allowing for the 1 inch offset of the motor to the passenger side. Or maybe it was something just unique to mine.
Dan,
I did have some fitment issues on my 289 car.
When I first installed the headers, the collector on the driver's side was very close to the brake / clutch hard lines. Talked with Bob P. and we determined due to a tolerance stack up, the motor was sitting too low. Made some 1/4" thick steel plate shims that were powder coated and put between the frame and motor mounts. Next step was to level the motor in the car, used a straight edge on top of the motor as a sightline to a horizontal seam in the firewall.
Then to get the pipes / muffler to align and sit properly under the car we wound up cutting off about 1" from the length of the collector on the passenger side. The driver's side we took off maybe 3/8". A little tweaking here and there does the trick. Sounds like you have everything lined up on your setup. I would not let the 2 degree bend bother you, seems like a good solution to the problem. Be sure to add the insulation under the floor and above the muffler if ERA did not already install that for you.
I have about a 3/4" space between the top of the muffler housing and the floor insulation. No heat issues so far.
There are bound to be a few things here and there that need to be tweaked with installing parts, but overall I have to say things go together pretty well on the ERA.
When you are finished, take some photos would be interesting to see what you have done.
I put an under car exhaust, exiting before the rear wheel on my ERA FIA and really like the look, sound and no snake bites! I would do it again.
The muffler that fits & ERA recommended is the Dynomax #17762. It just fits between the frame outriggers, and the main frame rail & bodywork. Not sure if the frame setup is the same on the 427 ERA car. Best to check with Bob to see how much room there is. Also, if you are considering this option, be sure to let Peter know before they cut holes in the fenders for side pipes.
You will lose some horsepower compared to traditional 427 side pipes, which may or may not be a big deal for you. Also, if you go with the Jag rear suspension from ERA, you have the option of exhaust to the bumper should you want to try that.
Start with the under car setup, if you find you don't like it, you can always cut the fenders and go with side pipes.
Cobra Make, Engine: Former owner of Long Live the Bow tie Contemporary #102 427 Chevy .30 over Merlin heads 11to1, TBI injection
Posts: 754
Not Ranked
I like that system. But there has to be some way to have the under car system with some kind of cutout go to the sidepipes for the rock n roll sound. I love the sound of the sidepipes but most of the time I would like it not so loud it sets of bank alarms.
I don't think I agree with an undercar exhaust making less horsepower. It just depends on what size mufflers you go with.
However, most sidepipes are extremely restrictive and the collectors on sidepipe headers are sometimes at extreme 90° angles. There have been members here that dyno'd with and without sidepipes and there has been 100hp difference.
The horsepower difference is one of the reasons why I would go with undercar exhaust...
Cobra Make, Engine: Unique 427 S/C, FE 440, top-loader, 3.31
Posts: 130
Not Ranked
Just be sure to get your seat mounts and belt mounts where you want them. The nuts will be above the muffler. Put some radiant heat barrier on the underside of the body too. Keep the legs and butt cool.
I don't think I agree with an undercar exhaust making less horsepower. It just depends on what size mufflers you go with.
However, most sidepipes are extremely restrictive and the collectors on sidepipe headers are sometimes at extreme 90° angles. There have been members here that dyno'd with and without sidepipes and there has been 100hp difference.
The horsepower difference is one of the reasons why I would go with undercar exhaust...
Brent,
I agree ... it does come down to what muffler one uses. In the case of 289 ERA, as Wolf mentions there is not a lot of room to tuck a muffler up underneath the car, at least on the FIA, can't speak to the 427 ERA.
The dynomax #17762 that fits is not that large ... 2" diameter pipe IN and OUT, but it flows pretty well and sounds great. I would think the true FIA side pipes would flow better, but without a side by side comparison hard to say for sure.
The custom SpinTech mufflers that HealeyRick is running look like they would fit under just about any car.
I like the looks of the under car setup and makes getting in and out that much easier.
How quiet is it with the dynomax muffler?
Also some v8's have a balance cross over pipe, is that necessary?
With the underbody pipe, I have seen a stainless steel side plate along the body, wich looks nice and stops stone chips on the rear guard.
JD
How quiet is it with the dynomax muffler?
Also some v8's have a balance cross over pipe, is that necessary?
With the underbody pipe, I have seen a stainless steel side plate along the body, wich looks nice and stops stone chips on the rear guard.
JD
JD,
A bit quieter than side pipes, but still loud enough to sound like a Cobra
Cruising speed on the highway is a combination of exhaust sound and wind noise, the 302 sounds particularly good from 3000 to 6000 RPM.
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Undercar exhaust exiting ahead of rear wheel
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