Exhaust Termination Boxes
 

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.

Re: Exhaust Termination Boxes
 

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.

Re: Exhaust Termination Boxes
 

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

Re: Exhaust Termination Boxes
 

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.

Re: Exhaust Termination Boxes
 

"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.

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Any progress?

Re: Exhaust Termination Boxes
 

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.

Re: Exhaust Termination Boxes
 

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.

Re: Exhaust Termination Boxes
 

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. :)

https://www.thirdgen.org/forums/tpi/...-cold-air.html

Re: Exhaust Termination Boxes
 

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.

Re: Exhaust Termination Boxes
 

Haha. You = awesome.





...Sorry for going offtopic. :eek:

Re: Exhaust Termination Boxes
 

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.

Re: Exhaust Termination Boxes
 

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.

Re: Exhaust Termination Boxes
 

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.

Re: Exhaust Termination Boxes
 

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 :)

Re: Exhaust Termination Boxes
 

Addicted to the laughing gas? :)

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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

Re: Exhaust Termination Boxes
 

"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.

Re: Exhaust Termination Boxes
 

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

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

Re: Exhaust Termination Boxes
 

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

Re: Exhaust Termination Boxes
 

"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.

Re: Exhaust Termination Boxes
 

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

Re: Exhaust Termination Boxes
 

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.

Re: Exhaust Termination Boxes
 

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.

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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

Re: Exhaust Termination Boxes
 

Subscribed. This is an interesting concept, makes sense but seems difficult to do well under a 3rd gen. I am one step further than the termination box - I just have the termination - right after the Y pipe. The headers are 1 5/8" SLP shorties, and the Y is right under the passenger's door hinge, and my termination is about 6 inches after that y-pipe, right where the cat once was. I dropped the exhaust on day on a whim, and couldn't have been happier with the results. I had a 3" catback to a flowmaster behind a very mild cam 305, but going to an open dump was like a light switch for this motor. Better power everywhere, from off idle right on up to 5700rpm. The motor used to flatten off at about 5200rpm with the catback, without its still pulling at 5700rpm - I'd like to take it even further, but on a relatively stock valvetrain and bottom end, I keep my shifts at about 5400.

A termination box to bring some of the noise back under control might be just the way to go, keep us posted.

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"I think that PipeMax program was the most expensive piece of software you've ever used."

Hahaha. It is the guiding light to the end of the horsepower tunnel and my wallet. :)

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Here are some progress pictures of the transmission support I'm making up to allow the exhaust tube to pass by without dragging on the ground. I also will remove the torque arm mount off the transmission to the support bracket. It will also have a driveshaft loop mounted on it.

Re: Exhaust Termination Boxes
 

Difficult to tell from the single photo. Will the boxes be installed parallel to the centreline of the car or across it? ( like an OEM muffler ).
It's great to see some progress. Seems we've been discussing it forever.
Keep at it and good luck.

Re: Exhaust Termination Boxes
 

Regarding the trans crossmember.
Do you think the aluminum has the fatigue resistance to stand up to what you'll put it through? I've seen less robust pieces than yours ( made of steel however ) that can't handle the constant compression, torsion and tension. Particularly the torque arm support.

Re: Exhaust Termination Boxes
 

Across it under the oil pan. I edited my post for more clarification

The transmission support cross member is far from complete. There are many gussets yet to be installed for increased strength and that includes the torque arm mount.

Re: Exhaust Termination Boxes
 

I wasn't commenting so much on the construction (and it's an excellent looking piece) but rather the phyisical limitations of aluminum in general.
I'm sure you've planned for all the abuse you'll give it.
Looking forward to the finished product.

Re: Exhaust Termination Boxes
 

applaud you for your efforts. Your actually going thru the steps thats great to see. I've talked about this but never got around to even testing cutouts for proper length exhaust let alone planning termination boxes

oh well i'll get around to it someday

Re: Exhaust Termination Boxes
 

Thanks guys. We will find out on the aluminum. Gary Stein who does the welding has a fabrication shop where he designs and makes, roll cages, car frames, motor mounts and you name it for car racing. Anyways he thinks it will work once we get all the gusset/bracing supports in place. It should be pretty stout once it is all done.
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atc3434 wrote: "I am one step further than the termination box - I just have the termination - right after the Y pipe."

Yep, providing the distances are correct by the open pipe you did what I'm trying to duplicate with the termination boxes.

Re: Exhaust Termination Boxes
 

A similar effect can be had with an "x" pipe, as the pulse nature of exhaust will make it appear to the exhaust that the single pipe "doubles" in area at the X. Placement of the x pipe on a dual system is critical to power, but the only way to know where it works best on a given system is to keep moving it and and dyno testing, and I don't know anyone who is really up for that.

Looking forward to learning something, keep up the good work!

TA

Re: Exhaust Termination Boxes
 

Probably should start another thread on this. Most of you know I'm upgrading to the 4L60E transmission. I have bought the TCI stand alone controller. Here is a picture of it mounted on the base I made up and put a couple of switches on it.

One switch is "dyno mode" so it will automatically lock up the torque converter at any speed you put in the program. The A/B switch is for two different programs that control the transmission. The A mode will be for the street and the B mode will be for the track.

Re: Exhaust Termination Boxes
 

This is also interesting. I've cooked a couple of 700R4's ( my own doing I'm sure ) and I've been checking out the 4L60E.
I'll subscribe to any new thread you start on this one.
PS. You have way too much time on your hands!

Re: Exhaust Termination Boxes
 

I bought one of Dana's kits at Pro Built Transmission. I told him I wanted to spin the motor to the 7000rpm range and the horsepower would not exceed 600 for a little safety factor. So we shall see.

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Does it work for a 4l80E?? you should start another thread :)

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Yes it does. Just check the software box that you have a 4L80E. In fact there are quite a few extras such as manuel shifting.

Re: Exhaust Termination Boxes
 

What improvements do you expect from the 4L60E, as compared to the 4L60/700r4?
Bill

Re: Exhaust Termination Boxes
 

same tranny but with adjustable shift points via electronics. you can precisely dial in the shifts much easier than playing with governor weights/springs. Much more accurate so you should beable to get the most efficent 1/4 mile times out of it.

Re: Exhaust Termination Boxes
 

Exactly. I could have spent the money to build up my 700R4 to handle the power and rpm and have the same problems with a shift point as I do now.

Now with the 4L60E all I have to do is stab the throttle and go with the shifts points already dialed. Makes it so much easier for someone with limited driving skills like me. :)

Re: Exhaust Termination Boxes
 

How is the termination box coming along? Any progress pics?

Re: Exhaust Termination Boxes
 

Yes, I should have some pictures maybe sometime next week. This will be the passenger side one. It will be about 1/2 done. I will have to wait for the new motor to be installed the car to totally finish it off.

I believe I can finish off the one that goes under the oil pan without having to have the motor in the car. I'm waiting on the short block to be finished so I can complete it.

Re: Exhaust Termination Boxes
 

I have the passenger side exhaust termination box back from the welder. I have taken 3 pictures to post showing the progress so far. The box goes under the passenger seat where the factory exhaust is routed.

The 45 degree outlet is where the catalytic converter will go. The outlet is tapered from 3.5" to 2.75 inch. The notch is to clear the frame support member at that location. I will have to have the motor in the car to finalize the other end of it. I have tried to have no flat surfaces outside that small portion on the oval itself. Here are the pictures.

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What is the volume of the box?

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Right now about 430 cubic inches. It might go up some if I have to add an extension off to the side to meet the collector pipe. The length of the collector pipe is the most important length when tunning the exhaust. So that cannot change.

Re: Exhaust Termination Boxes
 

Hey, Allen

When are we going to be able to have a look at the beast?