Switching side pipes to under car exhaust?

[Tom Wells]

ZOERA-SC7XX,

Also would make for HOT floorboards.

Don't know where you got that opinion!

My Cobra's floor is always cool. There is approximately a square foot (maybe two square feet - it's been eight years) of thin aluminized fiberglass insulation placed above each muffler. Even on 90 degree days with much idling at stoplights, or in parades, there's no heat coming from the floor.

Tom

[Ant]

I have had some burns to the inside of my legs from sidepipes.

I dont know about the power of your cars but this car I am building there aint a show in hell with the Reynard chassis etc unless you put the exhaust down the transmission tunnel inside boiler lagging etc as I attemped with an eight into one design, I gave up and built a complete system stepped headers going into merge side pipe collectors, with stainless 3" inside diameter perforated tube rolled and welded myself plus to get it quiet for round town insert a length of 2" perf tube wrapped in stainless and glass sound deadening, very restrictive but reports that you can get down to 92db with a basic engine so my nascar engine should be under its requirement of 98db to get certified.

Undercar looks better as it shows the nice bodyline etc (I hate sidepipes) but with 675bhp I havent the room to even run a 3" diameter area oval tubes underneath and the worst problem is where to fit large capacity mufflers, sometimes wish I had built a GT40 as you can do anything with them behind the engine.

[Newsnake]

I have been a member CC for very short time and I shocked how helpful and knowledge everyone has been. I think 427 roadster or a le mans(?) 289 might make some sense. Thank you all for the great insight and thought provoking answers.

With respect,
Mike

[Or Birdman]

I would just get rid of the Kids! BG

[bdeutsch]

As luck would have it, just received my latest edition of Kit Car Builder. Beginning on Page 48, there is an article regarding How to Build an Undercar Exhaust for a Cobra that had side pipes. Story and photos by the author, Dan Burrill.

Certainly not an expert on fabrication, but his approach looks very good.

Otherwise, hope all have a happy holiday season and a safe and prosperous New Year.

Bob

[Outwest34au]

Here are a few pics of my underbody system, rear exit with jag rear end. May give you some ideas.
Exhaust pics

Cheers

[mdross1]

When clearancing the frame for undercar exhaust,we welded in plate steel where mufflers were to be placed for heat deflection,it also made the floors rock solid.The tail pipes were routed under the 9" differential.The suspension fully extended does not touch the exhaust.Makes removing exhaust from header flanges back a 10 minute job,it looks great as well.

[Dwight]

I have given a lot of kids ride in mine with no burns.

We given 200 to 300 people a ride at the London Cobra Show every year and I have not heard of anyone getting burned.
Maybe some have but I heard of any.

I think the kids can learn to get into and out a Cobra without getting burned.

Dwight

[392cobra]

Kids will learn and they heal pretty quick.

[Bruce M]

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?

I built mine that way for the same reasons in 1982. I have 3" collectors - flowmasters into 3" tips out the rear. I had ro install converter shields to keep the heat down.

[mdross1]

No doubt kids can climb in and out with rubber skeletons.Near 50 when considering exhaust and climbing in and out side exhaust equipped cars,knew it was only going to get worse.Besides after owning a big block Vette with side exhaust I had enough of the noise.

[maurice19]

ANT,

Not very often you hear boiler lagging, bring back memories of my 41 years as a lagger.

Maurice Lawrence

[Ant]

Maurice,

Sounds like good memories, we had the big woollen mills next door to my parents beekeeping business and I spent many an hour roaming the lagged pipework etc, that work is now all long gone overseas for cheap labour and we and the mill are no longer there!

What I have used is KA Wool (white dense cotton wool like) I think it is used for boiler lagging as it can sit against a boiler and not burn or transfer heat, but doesnt like water so its very good behind slight stand off firewalls probably more so if you have under floor exhausts if you used thin alloy panels and sandwiched the wool if heat is an issue!

[FredBMOC]

I have a 9 year old daughter and I take her to school on my Cobra with sidepipes frequently and without issue; she simply stands up on the passanger seat and jumps out, no sweat....

[Bruce M]

I built my Contemporary with 3" collectors into Flowmasters with heat shields above and 3" tips out the rear. Sounds good, ground clearence is fine and no burnt ankles. Bruce M

[cobracrazy]

Look at the way the pipes are mounted on an FIA Cobra from Shelby or ERA. You can doe the same on big block car. They won't burn the kiddies, mine never have..

[DanEC]

Originally Posted by kayakjack

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


Jack

ERA does - full undercar and tailpipes. I'm going undercar on mine with their headers/collectors but plan on doing my own tailpipes.

[mdross1]

Originally Posted by Ant

I have had some burns to the inside of my legs from sidepipes.

I dont know about the power of your cars but this car I am building there aint a show in hell with the Reynard chassis etc unless you put the exhaust down the transmission tunnel inside boiler lagging etc as I attemped with an eight into one design, I gave up and built a complete system stepped headers going into merge side pipe collectors, with stainless 3" inside diameter perforated tube rolled and welded myself plus to get it quiet for round town insert a length of 2" perf tube wrapped in stainless and glass sound deadening, very restrictive but reports that you can get down to 92db with a basic engine so my nascar engine should be under its requirement of 98db to get certified.

Undercar looks better as it shows the nice bodyline etc (I hate sidepipes) but with 675bhp I havent the room to even run a 3" diameter area oval tubes underneath and the worst problem is where to fit large capacity mufflers, sometimes wish I had built a GT40 as you can do anything with them behind the engine.

Took my 460ci powered car to Tubular Automotive in Mass and had racing headers built then sent them Jet Hot for ceramic coating.Stainless Specialties custom built the chambered mufflers,local muffler shop built the rest.Also had to use cable operated clutch to give the headers all the room they need.

[JeepSnake]

Unique Motorcars also will build a kit with undercar exhaust. The Weavers converted my FIA car from sidepipes to street-type exhaust about a year ago (I've always liked the look, and I wanted to protect my 2 year old daughter as well.). After a lot of research on mufflers (many thanks to the tech guys at Flowmaster), I used the Hushpower Series II Shorties (12 inch case). These are typically used as a resonator in conjunction with the longer (18 inch case) Hushpowers. However, they are perfect by themselves for a Cobra, due to their small size, heat insulating properties, and "just right" exhaust note.

Based on my horsepower levels (~325 at the flywheel - very conservative engine around these parts), I went with 2.25" pipes. The headers are silver ceramic coated to keep down heat in the engine compartment, but the pipes are flat black ceramic to help them "disappear" underneath the car. With the Hushpowers, I actually picked up a little ground clearance compared to the sidepipes that were on the car originally.

In short, I love my undercar exhaust! (And my daughter does too; she wants to ride in the Cobra everywhere now!)

Hope this helps!

[snakebitekit]

The FIA body style the pipes flow under the rocker panels not even close to being "bit".
No hole to repair or fill in, if you want ERA will build the FIA style car with an under exhaust system.