The Official Hot Rod Thread - Part 4: Burnouts for Distance

[Bigtanker]

I kinda figured. A Fox Body with a 5.0 and a pair of 3 chambers........ Sweet sweet sounds.

What series are they? 2 or 3 chamber.

 

[femurphy77]

I kinda figured. A Fox Body with a 5.0 and a pair of 3 chambers........ Sweet sweet sounds.

What series are they? 2 or 3 chamber.

40's, 2 chamber. I typically use 3 chamber mufflers if there's room but in this case it's pretty tight. The 3" mandrel bent 90's are 6" x 6" and it's pretty tight everywhere behind the driver's seat. The last car sounded so good at full tilt that it'd make you cry if you were of the XY chromosome group.

 

[thunderchicken]

Haven't really been giving the exhaust on the racecar any thought lately because it's not been really high on the priority list. Since there is a fairly decent probability that the car may be able to run soon. I've been giving it some thought recently and with the rear suspension links in place the mufflers no longer are able to live under the back seat humps. With the subframe connectors in the way getting from the headers out from under the car is problematic. Of course, I could raise the car up into the realm of some of the 4 wheel drives you see running around but the intention is to keep it as low as I can without impairing the suspension travel to the point of binding thru normal range of motion while on course.

I've pretty much decided that the only way to do it is routing the exhaust up into the back seat area install the mufflers there and have them exit out the body in the area where the brake scoop is on the right side of the 66 Shelbys.

I'm using 3" aluminized straight tubing and mandrel bends and will tack it all in place above the floor line but want to use the big band clamps to join it where it goes thru the floor so I can pull it out when/if necessary. Of course, since I'm going to be cutting thru the floor and probably welding in various tabs and brackets, I guess I'll hold up on painting the under carriage and interior for a few more weeks.

At least I'm starting to work on it again and "MAY" actually have this thing able to move under its' own power soon.

Right now, I'm looking at putting the mufflers on top of the hump, bring the pipes up thru the floor behind the driver's seat and then work the exhaust thru/around the cage tubes to bring it out the right side.

View attachment 199037

Can you give us picture from underneath?
I'm thinking there has to be a better way to get the exhaust out the RH side without bringing it inside the car.
How would the sanctioning body feel about that?

Do you have to run actual mufflers or is this more of a "in the spirit of the rules" kind of deal? I ask because we used to run some 4" round mufflers that came right off the collectors and just had a little turn out on the end and they tucked up under the car really well. Obviously different applications

 

[thunderchicken]

FE- what about something like this right off the collectors and then just run the pipes right along the floor pan and dump them out in front of the rear tire on the RH side?

 

[femurphy77]

Can you give us picture from underneath?
I'm thinking there has to be a better way to get the exhaust out the RH side without bringing it inside the car.
How would the sanctioning body feel about that?

Do you have to run actual mufflers or is this more of a "in the spirit of the rules" kind of deal? I ask because we used to run some 4" round mufflers that came right off the collectors and just had a little turn out on the end and they tucked up under the car really well. Obviously different applications

Pictures forthcoming, routing the exhaust that way is permitted and we have noise sensitive sites where they monitor sound levels and will dq you if you exceed.



The black lines represent the two suspension links off the bottom of the pumpkin. The red is where I used to place my mufflers but that was on stock rear suspension, leaf spring equipped cars, the green lines are the tentative route under the car for the exhaust with the roughly round blotches representing where it will transition up under the floor. If I keep both outlets pointing towards the right side I won't have any "Mario Brothers" piping to get the exhaust out of the right side.

None of this is in stone so speak up, until I start welding up the in-car portion of it I'm not committed.

I'd even thought of side exhaust but again it would have to go under the frame/subframe connectors decreasing the ground clearance even more on a car that will have already limited ground clearance once it is in fighting form. I'd thought of fenderwell headers but have too much in my custom built headers to scrap them and start over there. Just another day in paradise but then again I got nuttin' in the mad scientist department compared to Jeff S!

 

[thunderchicken]

Pictures forthcoming, routing the exhaust that way is permitted and we have noise sensitive sites where they monitor sound levels and will dq you if you exceed.

View attachment 199114

The black lines represent the two suspension links off the bottom of the pumpkin. The red is where I used to place my mufflers but that was on stock rear suspension, leaf spring equipped cars, the green lines are the tentative route under the car for the exhaust with the roughly round blotches representing where it will transition up under the floor. If I keep both outlets pointing towards the right side I won't have any "Mario Brothers" piping to get the exhaust out of the right side.

None of this is in stone so speak up, until I start welding up the in-car portion of it I'm not committed.

I'd even thought of side exhaust but again it would have to go under the frame/subframe connectors decreasing the ground clearance even more on a car that will have already limited ground clearance once it is in fighting form. I'd thought of fenderwell headers but have too much in my custom built headers to scrap them and start over there. Just another day in paradise but then again I got nuttin' in the mad scientist department compared to Jeff S!

How thick are those Flowmasters?
What about just place the mufflers near where the green lines start and just use simple turn downs and let the exhaust dump under the car? Won't your custom headers be lower than the subframe connectors anyway?
What about notching the rear floor pan above the mufflers to create a pocket of sorts to gain clearance? You might could also always go from 3" round pipe to 3" oval pipe to save some more clearance

Routing the pipes up into the car just seems like it adds unnecessary piping.

 

[femurphy77]

The flowmasters are 4" thick, the headers suck tight into the body (one of the reasons they were so damned expensive). I can notch the floorpan for exhaust clearance and hadn't even thought of that till you mentioned it. DUH! Rethinking as we speak.

 

[thunderchicken]

The flowmasters are 4" thick, the headers suck tight into the body (one of the reasons they were so damned expensive). I can notch the floorpan for exhaust clearance and hadn't even thought of that till you mentioned it. DUH! Rethinking as we speak.

If it were my car, I would probably look hard at notching the floor rather than route piping inside the car and back out. Maybe that's the answer and maybe not, just an idea

 

[churchmouse]

I'm a FlowMaster fan. I started running them when you could no longer get REAL Corvair turbo mufflers and never looked back.

Man I forgot all about the much sought after Corvair Turbo muffler. It was the best sound around during the Thrush/Cherry bomb era.

 

[churchmouse]

Pictures forthcoming, routing the exhaust that way is permitted and we have noise sensitive sites where they monitor sound levels and will dq you if you exceed.

View attachment 199114

The black lines represent the two suspension links off the bottom of the pumpkin. The red is where I used to place my mufflers but that was on stock rear suspension, leaf spring equipped cars, the green lines are the tentative route under the car for the exhaust with the roughly round blotches representing where it will transition up under the floor. If I keep both outlets pointing towards the right side I won't have any "Mario Brothers" piping to get the exhaust out of the right side.

None of this is in stone so speak up, until I start welding up the in-car portion of it I'm not committed.

I'd even thought of side exhaust but again it would have to go under the frame/subframe connectors decreasing the ground clearance even more on a car that will have already limited ground clearance once it is in fighting form. I'd thought of fenderwell headers but have too much in my custom built headers to scrap them and start over there. Just another day in paradise but then again I got nuttin' in the mad scientist department compared to Jeff S!

Our resident mad scientist rules.

 

[thunderchicken]

Our resident mad scientist rules.

He's an animal

 

[Jaybird1980]

The exhaust is already going to be below the subframe connectors at the transmission cross member right? I would find a way to not bring it into the interior space.

 

[femurphy77]

The exhaust is already going to be below the subframe connectors at the transmission cross member right? I would find a way to not bring it into the interior space.

It's got a double hump cross member so the exhaust is within an inch of the floor up to the mufflers.

 

[Jaybird1980]

It's got a double hump cross member so the exhaust is within an inch of the floor up to the mufflers.

Got it. So there's not enough room to run straight into the mufflers and then turn downs at an angle towards the outside?

Like this, I'm assuming lines are in the tunnel?

 

[jeffsqartan]

Just another day in paradise but then again I got nuttin' in the mad scientist department compared to Jeff S!

At least you know your place

Do I need to come over and give some suggestions?

Mustang is in the garage. Can confirm that the driveshaft and exhaust were not the source of my vibration.
Removing the transmission tomorrow to see what I find with everything else. Also ordered a pilot bushing at O'Reilly. Do I need to check that guy out with a magnet and make sure it doesn't attract?
Found out I have spare Ford Performance bearing that I can use as well. I like having options.

 

[Jaybird1980]

At least you know your place

Do I need to come over and give some suggestions?

Mustang is in the garage. Can confirm that the driveshaft and exhaust were not the source of my vibration.
Removing the transmission tomorrow to see what I find with everything else. Also ordered a pilot bushing at O'Reilly. Do I need to check that guy out with a magnet and make sure it doesn't attract?
Found out I have spare Ford Performance bearing that I can use as well. I like having options.

I played it safe, but I don't know if it was necessary. Just peace of mind.

 

[femurphy77]

Got it. So there's not enough room to run straight into the mufflers and then turn downs at an angle towards the outside?

Like this, I'm assuming lines are in the tunnel?

View attachment 199213

This would work notching it up into the floor but I don't want to reduce the ground clearance anymore than it is and upon further review notching the floor will require redesigning my seat mount and battery mount so I'm probably back to up thru the floor pan again.

I'm working on other things right now so this won't be happening for another couple of weeks so still time to bend the elbow a few times and think about it.

 

[thunderchicken]

Haven't really been giving the exhaust on the racecar any thought lately because it's not been really high on the priority list. Since there is a fairly decent probability that the car may be able to run soon. I've been giving it some thought recently and with the rear suspension links in place the mufflers no longer are able to live under the back seat humps. With the subframe connectors in the way getting from the headers out from under the car is problematic. Of course, I could raise the car up into the realm of some of the 4 wheel drives you see running around but the intention is to keep it as low as I can without impairing the suspension travel to the point of binding thru normal range of motion while on course.

I've pretty much decided that the only way to do it is routing the exhaust up into the back seat area install the mufflers there and have them exit out the body in the area where the brake scoop is on the right side of the 66 Shelbys.

I'm using 3" aluminized straight tubing and mandrel bends and will tack it all in place above the floor line but want to use the big band clamps to join it where it goes thru the floor so I can pull it out when/if necessary. Of course, since I'm going to be cutting thru the floor and probably welding in various tabs and brackets, I guess I'll hold up on painting the under carriage and interior for a few more weeks.

At least I'm starting to work on it again and "MAY" actually have this thing able to move under its' own power soon.

Right now, I'm looking at putting the mufflers on top of the hump, bring the pipes up thru the floor behind the driver's seat and then work the exhaust thru/around the cage tubes to bring it out the right side.

View attachment 199037

Looking at this picture, from what I can tell it looks like the seat mount and battery mount maybe up high enough to get those mufflers tucked up out of the way easy enough. Surely 3" exhaust pipe will be lower than those 2x2 or 2x3 frame rails/connectors

What kind of ride height/ground clearance do you plan to have? What about looking at those cone mufflers that slip inside the collectors?

 

[femurphy77]

This is the exhaust I built for it about 26 years ago. Still solid and ready to rock. Cost me almost 300 bucks back then, nowadays that'll get you the mufflers and collectirs.

 

[Jaybird1980]

This is the exhaust I built for it about 26 years ago. Still solid and ready to rock. Cost me almost 300 bucks back then, nowadays that'll get you the mufflers and collectirs.View attachment 199314

How far below the connectors does it hang in the circled area?


I know I'm just looking at pics, but it sure seems like you could salvage some of the old system and just move them up to where I mentioned earlier, just tuck em up and it shouldn't be far below the connectors. You could go to oval pipe in the tight area to save a little, but I'm sure that stuff is pretty pricey.

You must have this thing slammed, my 3rd gen was low and my exhaust was just under the connectors and never had any issues.