If engine is coming out...what exhaust upgrade?

[VelodromeRacer]

Ok,

The existing header is old and not jet coated...
The car has a race prepped 948 and straight pipe out the rear of the car upon leaving the header...

I wonder about a few things...
1. Do other vintage bugeye racers coat the headers?
2. Should I run a straight pipe or a muffler?
3. Should I be worried about the noise a 948 makes and limits at tracks?
4. I am building a 1275 motor for the future as a backup motor...how will this exhaust impact that motor..different header?

Ideas? Supertrapp?

Pictures?

Thanks.

 

[Bugeye58]

In numerical order.
1. I run coated headers. Others don't. I also have a through-tunnel exhaust.

2. That depends on the sound limits where you will be racing at. A properly sized muffler won't hurt power levels at all.

3.Yes. My 948 will not pass sound limits a Waterford without a muffler. Of course, we have the tightest sound regulations of any track in the world. Unmuffled, I run about 94dB. I have to be below 75 at Waterford.

4. The 1275 will require a different exhaust, including the header.

I run a small Flowmaster for a muffler. I hate Supertrapps.
By the time you take out enough plates to make a significant difference in the noise level, they seem to strangle the engine. Other folks like them. I'd get more opinions on them from folks who run them.

Next?
Jeff

 

[aeronca65t]

All these are just my opinion:


1. Do other vintage bugeye racers coat the headers?

Yes, if you want it to look nice and resist rust long-term. May also reduce under-hood temps slightly but not enough for any big power gain. Nice, but not a *must*.

2. Should I run a straight pipe or a muffler?
Straight pipe mostly. Simpler and lighter. Exit under the car in front of the left, rear tire. The "through the tunnel" systems are neat, but they're mega-bucks and very tight to work around. For vintage, you don't really need them

3. Should I be worried about the noise a 948 makes and limits at tracks?
Even full-race 948s are pretty quiet compared to other, bigger engines. But it depends on where you run. I run at Lime Rock once a year and I have a bolt-on tube-muffler that slips over the exhaust pipe and runs along the side of the car. I can pull it off in 5 minutes. None of the other tracks in my area require muffling. Where are you intending on running? Check their dBA requirements (your local club should know)

4. I am building a 1275 motor for the future as a backup motor...how will this exhaust impact that motor..different header?
I'd use a Long Center Branch header (LCB). They list a different header for the 948 and the 1275, but for vintage, I bet you could just use the 1275 header for either engine. Call APT and see what they say. You can find them here:
https://www.aptfast.com/APT_Parts/Aseries_Parts/a_Exhaust_Headers_Systems.htm

Ideas?

Supertrapp? I dislike the Supertrapp muffler...very restrictive. If you need to reduce sound, a cheap "turbo" or "saugage-shape" muffler is better. You can get then from Summit Racing.

You can sort of see my "Lime Rock" muffler in ~This Picture~ (keep in mind that my 1500 car has the exhaust on the opposite side of a 948/1275 car).

Edit--Hey Jeff. That's funny...we even agree on some things /bcforum/images/%%GRAEMLIN_URL%%/jester.gif

 

[Bugeye58]

Nial, I think it's more along the lines of "Great minds think alike".
That's my story, and I'm sticking to it! /bcforum/images/%%GRAEMLIN_URL%%/grin.gif
Jeff

 

[Hap Waldrop]

The 948s with a straight pipe that I've driven run about 100 DB, just under SCCA limits of 103, the 1275 in limited prep build ran about the same, the FP 1275 full prep motor had to have a muffler to keep it under 102. As far as the direction on the exhaust run it straight out the back, the longer, the better for RPMs.

 

[VelodromeRacer]

If I run it straight out the back as it is now, is it possible to possible cut it back a bit so that I can keep a pipe fitted when I don't need to silence it and then I can remove the pipe and fit a muffler at the end if I need to silence it?

I like Aeronci65t's thought of being able to bolt on a muffler if I am asked to. I'll run with VSCDA in the midwest, so Mid Ohio, Blackhawk, Grattan, Gingerman will be the tracks...being new, I don't want to show up and suddenly be stuck because my car is too loud.

I figure since I'll have the engine out in a few weeks, (When Hap's gearbox arrives?) that I might as well upgrade the header as it looks like it could rust through right now and the header in my BJ8 was Jet Coated and really feels solid after that!

 

[Hap Waldrop]

The gearbox will probably go out the first part of the next week, I had to get a dust cover for the SAAB throw out bearing, and finish the top of the crate, it's quite a packing job to say the least. It's mouted on its own wooden crate within a box.

Back to the exhaust rather than run it short, I would just put a muffler on it, or you could you make to back section that slips on and bolts in place, one with a muffler and one without. A good suggestion on a mufflke that won't rob HP and yet is fairly small is the Walker Dynomax racing mufflers, thay make one that is 2 1/2" inlet and exahust, you can sleeve it samller if needed, it fairly compact, looks like a small glass pack, and its cheap, less than $50.

 

[Bugeye58]

I may as well get some good out of this picture. Here's a decent shot of the exhaust on my Bugeye. If I wanted to run sans muffler, I just pulled the rear hanger, and loosened the band clamp to remove it. The I'd just reinstall the turn down, or I could add another section of tube where the muffler was.
This muffler was actually a front resonator out of a prototype 2000 Euro Market GM S-10 Blazer.

The system isn't nearly as close to the fuel cell as it looks.
Jeff

 

[Michael Oritt]

Why does it say "This Space For Rent" on the bottom of the fuel cell?

 

[Bugeye58]

It actually says. "If you can read this, I've <span style='font-size: 11pt'><span style="color: #FF0000">really</span></span> screwed up". /bcforum/images/%%GRAEMLIN_URL%%/grin.gif

 

[blkcorvair]

I may as well get some good out of this picture. Here's a decent shot of the exhaust on my Bugeye. If I wanted to run sans muffler, I just pulled the rear hanger, and loosened the band clamp to remove it. The I'd just reinstall the turn down, or I could add another section of tube where the muffler was.
This muffler was actually a front resonator out of a prototype 2000 Euro Market GM S-10 Blazer.

The system isn't nearly as close to the fuel cell as it looks.
Jeff

Thats one way to show off a clean under carriage. If not for that who really see any handi work /bcforum/images/%%GRAEMLIN_URL%%/jester.gif

 

[VelodromeRacer]

I look at that picture, and after I wince, I say "the hood sacraficed itself for the sake of the frame"

I visited a exhaust shop today, a shop that does a bunch of race cars and a few cars that have been sold at Barrett Jackson. They are real interested in helping me come up with something.

Hap, I wasn't trying to push you on the box, when she arrives, she arrives. I did get the Tilton clutch assembly today.

Now I am looking at doing some work on the Aldon distrib.


WHEN WILL IT END!

 

[Hedgehog]

Velodrome, sound at BHF is 103db and is driver's right as you exit turn 6 (at the silo). Turn your exhaust tip to driver's right and you'll be fine. I've run 948s, 1098s, and 1275 Spridgets at BHF without muffler and have never had an issue.

Sound at RA is also driver's left at turn 14 entering the front straight. I've never had issues there either.

With a little luck, I'll be joining you in the VSCDA this year or next. Depends on time and resources to get the Midget in vintage trim.

 

[VelodromeRacer]

Great Thanks! I really look foreword to the start of the season. I'll get the car back out to Putnam park to go over the winter changes, which accordimg to my visa bill, are many. I think adding the Taylor-Race box from Hap and the Tilton clutch will be most noticable for me!

I am looking at getting the distributor rebuilt/recurved this winter as well.

Exhaust header from APT is off to get jet coated, then I'll figure what needs to happen with the rest of the pipes, but it sounds like a lack of muffler won't be a big deal.