Need exhaust advice on hot 383 build - Page 6 - Exhaust - Third Generation F-Body Message Boards

TheBadazz · 06-06-2008, 04:45 PM

Yeah that does look good. I was checking out the topic and i have done a few true duals on 3rd and fouth gens. I've done long and shorties, 2.5" and 3" all over the axle with no ground clearance issues and dynoed before and after. I must say that true duals done right will make a huge difference on a cars hp and trq out when tuned for the exrta flow. To me thats the only way to go.

1989GTATransAm · 06-06-2008, 04:59 PM

So, Orr89RocZ how is your project doing? What is the latest?

Orr89RocZ · 06-06-2008, 05:22 PM

haha its coming along... if all goes well i HOPE to start it up and do some break in this weekend. Y pipe is mostly done and i just need to get hangers installed for the exhaust.

see this thread for my exhaust progress
http://www.thirdgen.org/techboard/ex...om-y-pipe.html (My Custom Y-pipe for Spohn Crossmember)

1989GTATransAm · 06-06-2008, 05:41 PM

Like you we are all waiting on the results. Looks like you have everything together with a good plan. You should be putting down some good power.

skinny z · 06-06-2008, 09:11 PM

Quote:

Originally Posted by TheBadazz

Yeah that does look good. I was checking out the topic and i have done a few true duals on 3rd and fouth gens. I've done long and shorties, 2.5" and 3" all over the axle with no ground clearance issues and dynoed before and after. I must say that true duals done right will make a huge difference on a cars hp and trq out when tuned for the exrta flow. To me thats the only way to go.

Do you have any experience with terminator boxes?

Orr89RocZ · 06-06-2008, 11:01 PM

Quote:

Originally Posted by 1989GTATransAm

Like you we are all waiting on the results. Looks like you have everything together with a good plan. You should be putting down some good power.

I know and i appologize for how long this is taking me but you know you cant always focus 100% on the car project

I just feel i've been leading you guys on for months and months awaiting this build and its still not done. I should have had this done last month

1989GTATransAm · 06-06-2008, 11:51 PM

These things always take longer than expected. Thats why I'm saying this winter for the next mods on my car to be completed. I think you are better off taking a little longer and do it right the first time.

TheBadazz · 06-07-2008, 08:24 AM

Quote:

Originally Posted by skinny z

Do you have any experience with terminator boxes?

Yes I do, the systems we've done has been on stock cube heavy modded LS1s, 355-383 sbc heck we even got a sbc 355 with a tbi converted to lay down 380hp 390lbs. Basically you want the engine to see the collectors (tuned lngth of course) and that's it. No back pressure and not too loud (hard to get races)

Then all you have to do is make sure your tune is right.

skinny z · 06-07-2008, 08:26 AM

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Quote:

Originally Posted by 1989GTATransAm

These things always take longer than expected. Thats why I'm saying this winter for the next mods on my car to be completed. I think you are better off taking a little longer and do it right the first time.

Couldn't agree more.
Even when you think you're done there will be something else needing your attention.

TheBadazz · 06-07-2008, 08:31 AM

Quote:

Originally Posted by Orr89RocZ

I know and i appologize for how long this is taking me but you know you cant always focus 100% on the car project

I just feel i've been leading you guys on for months and months awaiting this build and its still not done. I should have had this done last month

Don't sweat it, it's better to take your time and do it right then to rush and have to fix on it all the time.

skinny z · 06-07-2008, 08:34 AM

Quote:

Originally Posted by TheBadazz

Yes I do, the systems we've done has been on stock cube heavy modded LS1s, 355-383 sbc heck we even got a sbc 355 with a tbi converted to lay down 380hp 390lbs. Basically you want the engine to see the collectors (tuned lngth of course) and that's it. No back pressure and not too loud (hard to get races)

Then all you have to do is make sure your tune is right.

Our problem has been lack of available room to build a suitably sized enclosure.

TheBadazz · 06-07-2008, 08:43 AM

[quote=skinny z;3782839]Our problem has been lack of available room to build a suitably sized enclosure.
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Not really, if you have access to a car lift or four 6 ton jack stands there's plenty of room when you make some simple mods. Fore the enclosure you can go with a 4" or 5" pipe, depends on the motor size and ci you need. Next on 10 bolt cars you will have to take a little metel off the pass side of the dif case (not much). Then slight mod on the upper part of the panhard brace and thats it. Enough room for your enclosure and two 3" pipes with your choice of mufflers.

mw66nova · 06-07-2008, 09:27 AM

i'm gonna need to see pics, cause i'm having a hard time visualizing what you're saying.

TheBadazz · 06-07-2008, 10:19 AM

Quote:

Originally Posted by mw66nova

i'm gonna need to see pics, cause i'm having a hard time visualizing what you're saying.

No problem, I'm work on a heavy modded 2000 Z28 right now. 1.75" pacesetter long tubes 3" trues, 4" res and two 3" bullets (TOOO LOUD) so I can get somes pics when I get to my shop.

Orr89RocZ · 06-07-2008, 10:48 AM

would love to see it! i know you can squeeze 2 3" pipes over the axle, especially if you take off the upper panhard bar support.

i'm thinking 5" pipe would work but not sure how you would join two 3" pipes into that and then back out again. you'd have to do a box it would seem and somehow weld around it to seal the joints

TheBadazz · 06-07-2008, 11:07 AM

Quote:

Originally Posted by Orr89RocZ

would love to see it! i know you can squeeze 2 3" pipes over the axle, especially if you take off the upper panhard bar support.

i'm thinking 5" pipe would work but not sure how you would join two 3" pipes into that and then back out again. you'd have to do a box it would seem and somehow weld around it to seal the joints

5" will work although a 4" long enough is good for 427 cubes. Joinning the two pipes is not hard. Just cut off a section of 4"/5" flare the ends hammer the two pipes to fit then weld it all up. After that just weld the y to the rest of the system. I don't know why GM didn't do this in the first place.

1989GTATransAm · 06-07-2008, 12:28 PM

Hmmmm. This is getting interesting. What kind of horsepower gain are you seeing? Pictures would be a big help. For most of us the collector ranges are 18" for best, 36" next and then 72".

Orr89RocZ · 06-07-2008, 01:51 PM

where can you buy 5 inch pipe, most places i've seen only carry 4. And where to get 4/5" flare? I know diesel trucks use 5inch pipe but i cant find it for sale other than in catbacks

1989GTATransAm · 06-07-2008, 06:22 PM

Here is a link to some 5" exhaust tubing.

http://store.airflo.com/4310-548.html

And some adapters.

http://store.airflo.com/exhaust-adapters.html

skinny z · 06-07-2008, 09:35 PM

Long live the terminator box. I'd like to see pictures too.

TheBadazz · 06-09-2008, 11:11 AM

Quote:

Originally Posted by 1989GTATransAm

Hmmmm. This is getting interesting. What kind of horsepower gain are you seeing? Pictures would be a big help. For most of us the collector ranges are 18" for best, 36" next and then 72".

Well here are some pics that we took over the weekend. We are now installing the sbfc. It's a convertable so I have to make some mods to get them on. This system has 100% of the ground clearance that the flow master cat back had. The car will be getting dynoed tmro so I'll have some more data for you guys. The car should put down 460 to 470 to the wheels.
As far as the hp gain it depends on the motor output and what you started out with. Most 350ci+ that's making 275+hp to the wheels with headers and a 3" cat-back see about 25 to 35hp gain after tuned duals and af/spark tunning. A GOOD tune is the key.
O by the way this car is going to race a 3rd gen that we also did a lot of work on (from paint to drivetrain) in the 1/8th mile.

skinny z · 06-09-2008, 11:22 AM

I'd love to see some pictures.
We've been pursuing a true tuned dual exhaust for a while now.
I've built my current system to allow for easy adaptation to resonator/terminator box if space and ground clearence permit.
The lowest point is at the crossmember (which is modofied) however the box would be beyond that with an average collector length of about 36". Still there's not a lot of room for a 700 cubic inch enclosure.

1989GTATransAm · 06-09-2008, 01:42 PM

Here is another picture of one way to enter a pipe into a termination box. You want it to extend into the "open air" an inch or two.

skinny z · 06-09-2008, 01:50 PM

Quote:

Originally Posted by 1989GTATransAm

Here is another picture of one way to enter a pipe into a termination box. You want it to extend into the "open air" an inch or two.

If my application, the header collectors end up a different lengths if they were to be stopped or cut off at the existing merge pipe. Extending them into the box (as per the spec) will allow me to stagger the ends to provide equal lengths of around 36".
Question remains. Where does it all fit?

TheBadazz · 06-09-2008, 02:04 PM

Here's a couple of pics.

TheBadazz · 06-09-2008, 02:05 PM

Here's another

TheBadazz · 06-09-2008, 02:12 PM

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