1989GTATransAm

I'm making this post for those doing research on the subject.

The idea for the exhaust termination box is for the exhaust collector to act like it is exiting into atmosphere. If done correctly the exhaust will "think" there is no exhaust system or muffler after the termination box. It is part of exhaust wave tuning. It can be a substantial horsepower gain.

You need the proper size header primary pipes, a good merge collector, the proper diameter collector pipe and the proper length for the collector pipe. This will all dump into the termination box. The good thing is this will work quite well with properly built shorty headers. You don't need long tube headers.

There are a couple of things I have found out in my research. Some of the information is from Jon Bauer(Bret's father) who built termination boxes for the Engine Masters Challenge. One problem will be heat under the car. One solution is to have the system sprayed with a thermal barrier such as used on headers. I will be going that route. Another problem is oil canning. You do not want to use a flat sided box. It will eventually tear itself apart with the exhaust pulses and have a "tinny sound". If you are using a larger diameter pipe I see no problem. Myself I will be using oval tubing.

David Vizard has covered the subject quite well in his exhaust science article for further information.

1989GTATransAm

I have acquired the material for my first termination box. Here are some pictures. I will be using this thread to show the progress. By the way this piece is around 415 cubic inches.

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	Exhaust Termination Box 001 (Large).jpg (97.6 KB, 107 views)
	Exhaust Termination Box 002 (Large).jpg (94.6 KB, 65 views)

drknow90rs_ss@y

Isnt this concept the same as a single chamber muffler? Forgive my ignorance, but...???

skinny z

I've been thinking about the oval tubing idea, or any large diameter pipe for that matter and am wondering if it qualifies under the "substantial change in cross sectional area".
An empty muffler case has been used as well as fabricated enclosures. These appeear to offer a greater difference in cross section ( I'm not refering to the actual box volume ) that can be provided with any oval tubing I've come across. It's difficult to tell from the posted pics. What size pipe is that?
Do your contacts agree with the idea? Personally I think it's our best shot at getting this to work with our limited work space. I'll be watching with interest.

1989GTATransAm

"Isn't this concept the same as a single chamber muffler?"

Possibly depending on how the muffler is designed and the cubic inches. Also it would have to be in the proper location to generate the wave tuning effect.

Skinny z. The tubing is 4"x7" and 16 gage. I don't think substantial change in size has to be very much. Just look at the one Vizard made up for the Corvette. The size of oval tubing for the passenger side exhaust will be 3.25"x6" and 16 gage.

My collector pipe diameter is 2.75" and corresponds to size recommended by PipeMax.

skinny z

Any progress?

1989GTATransAm

Hehehe. I just finished the Super Ram modification for someone else. Now that I'm back to working on my car the Super Cold Air Intake is next on the plate. No restrictions allowed.

My tubular K-member was to have shipped today. Should have it by next Friday. Next up is the new transmission support with the driveshaft loop. This will allow room for the exhaust pipe to pass through the area and allow for the termination box.

skinny z

Cold Air Intake!
Should we start a new thread for that one?
I've been trying to build an effective CIA for a carbed application for a while.
Short of a cowl hood there dosen't seem to be a lot of options.

1989GTATransAm

The CAI is for my TPI and I already have a thread on it. Here is the link with an updated picture from this evening.

http://www.thirdgen.org/techboard/tp...-cold-air.html (My Latest Cold Air Intake Design)

Orr89RocZ

wow good deal, glad to see your startin this. I havent gotten around to getting cutouts. I bought a nitrous kit instead, oh and a roll bar but that isnt getting installed probly for another month

I'll try to get cutouts in to do some testing on collector length to show what there is to gain when you design the system right.

IROCThe5.7L

Haha. You = awesome.





...Sorry for going offtopic.

mw66nova

can someone post up the formula for coming up with proper pipe size and location? the new motor will likely benefit from a larger diameter primary (ie, i'm running hedman lt's, would like to upgrade to the hookers) and when i do i'd like to reconsider the exhaust system once again. i'm currently running a single 3.5" exhaust and i'm wondering if i'll benefit from either a larger 4" or from going back to a dual 2.5" system with an x-pipe.

__________________
Matt

watch for updates at www.walterracecraft.com
vid of new motor: http://www.youtube.com/watch?v=weBt7kK7n68

1989GTATransAm

mw66nova your best bet is to get a copy of Larry Meaux's program called PipeMax. You can find it at www.maxracesoftware.com

That way you can plug in your motors numbers and your goals. The program will tell what size pipes are the best. Also does the intake.

1989GTATransAm

A little update and with good news. The tubular K-member arrived from RaceCraft today so I could take some measurements. Looks like I will have lots of room for the drivers side exhaust termination box. The passenger side termination box will go on the passenger side where the factory exhaust runs. Here are some pictures showing the placement of the termination box. I will have a serparate thread on the RaceCraft K-member. Here are the pictures.

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	RaceCraft K-member 001.jpg (393.2 KB, 25 views)
	RaceCraft K-member 002.jpg (395.9 KB, 41 views)

Orr89RocZ

it will be interesting to see how you lay all that out

i still havent gotten around to doing cutouts yet... my bad guys. that be some good data to get before and after cutouts with pipemax determined collector length. i got that nitrous kit and the power is awesome, i dont want to race on motor anymore

1989GTATransAm

Addicted to the laughing gas?

Orr89RocZ

lol yes. I hope to get it on the dyno soon if i could get a weekend date somewhere. Maybe if i could get the cutouts on then i can do a motor run, cutout motor run, then do the nitrous tuning

I do think these termination boxes will work i just dont have much room to do it

1989GTATransAm

"i just dont have much room to do it"

That is the problem and I had given up. But I saw an installation with a tubular k-member and the light bulb went on. That and a custom oil pan it will all fit. It looks like I can get in nine times the cubic inches of one cylinder.

skinny z

Hope we haven't lost a development engineer to the 'easy squeeze'.

skinny z

Do you think there would be sufficient space with LT headers and the tubular k-member?

Orr89RocZ

my headers dump before the crossmember by like 18 inches.

If i do the boxes i'll have to go to true duals, with 4inch tubes as my boxes, or i may beable to make my own using plate sheet steel. But thatts just more work

4inch may work, i wont beable to fit 5 inch... so thats out. unless i ovalize it.. but that would be difficult.

I think longtube cars need to do duals with boxes because the joint volume will have to feed twice the engine displacement and thats alot. on my setup, you could make a custom shaped box down the driveshaft tunnel but its tight in there and clearance will be lost. My clearance sucks as is

1989GTATransAm

"Do you think there would be sufficient space with LT headers and the tubular k-member?"

...and the exhaust termination box? I would have to say no. Maybe with mid length headers which would not be all bad. I think PipeMax says something around 13.5 inch primary pipes for my setup or 15" for a setup like Orr's.

With the tubular k-member and custom oil pan I think a custom set of long tube headers would fit just fine with plenty of ground clearance.

Orr89RocZ

Yeah thats the benefit, a k member and oil pan will make it easier to have nice longtubes that fit good and have better primary lengths..more equalized than most headers that fit these cars

shorties with the ypipe crossover makes it possible to put a box there

1989GTATransAm

Just a little update. My Canton custom oil pan came in today. This will allow me to run the drivers side termination box under the oil pan. Here are some pictures of the oil pan.

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	Canton Oil Pan 001.jpg (350.5 KB, 17 views)
	Canton Oil Pan 002.jpg (498.2 KB, 12 views)
	Canton Oil Pan 003.jpg (561.6 KB, 22 views)

1989GTATransAm

Update on the exhaust termination box. Here is the drivers side termination box with the exhaust exit now welded in place. The exit pipe will run along the passenger side of the transmission. The exit pipe is a piece of taper going from 3.5" to 2.75". Here is a picture.

Edit: The picture shown is how it would be installed if you were sitting in the drivers seat and looking forward and a little to your right. The header collector will enter from the left side of the picture. The termination box will fit under the oil pan going South North in the picture.

Attached Images

Exhaust Termination Box.jpg (64.2 KB, 31 views)

TA

1989GTATransAm

I think that PipeMax program was the most expensive piece of software you've ever used. We'll still keep an eye on what sort of results this brings.

TA

atc3434