Hi there! How is everyone? Hope everoyne had a good X-mas and got lots of goodies to bolt on to their trucks for plenty of flash and dash!



Me, I got a small bit of money....and that money is going towards a homemade 4" exhaust for my 93.

But I need some helpful tips if ya'll got any.

I managed to get a 6.5ft long 4inch pipe from a friend for free so thats one less bit Ill have to buy.
I also managed to get a scrapped, what seems to be, a 4" cat-back exhaust off of a 2nd gen....for free. So thats another bit of pipe I can hack and piece together.

Ill be using 6.5ft piece for my DP. For the flange on the DP I have a "drrr" question....
Do I use the 4" CTD flange... http://store.airflo.com/ad311.html or the regualr 4" flange http://store.airflo.com/88-415.html???

Seems like a pretty straight forward answer, get the CTD flange, but if that other 4" will work fine, its half the price too and Id rather get that.
Any brilliant answers for my dumb question would be great

Also, Im really not wanting to mess with all the bends in making it passed the T-case and Im debating on using some flex tubing http://store.airflo.com/ss4.html to go through there.
Anyone done this?
Any pros or cons to this?

And one final question from a friend, will it alter the sound in any way having the slight "baffles" of the flex tubing?

Any help would be awesome!
Thanks in advance.

 

Try here. You can buy the parts you need to go around the t case please don't use flex pipe and do it the right way.

http://www.dieselperformancesystem.c...rformance.html

Greg

 

Thanks, but if I was gonna spend that much money Id might as well go to Stans Headers and get a full 4" from the turbo back with hangers included.
Money is tight and spare time is ubiquitous...

 

That piece that goes around the transfer case though starts out at 3 inches. What would be wrong with flex pipe through there? I just wanna know, im in the same place right now.

 

hey bud if you are just wanting to get it done and dont really care about the looks of it the heck yeah go on and do the flex tubing, I have some on my truck for my stacks and I havent had a problem out of it yet. One word of warning though, the flex pipe might start to leak after a while. One of my buds has had this problem on his. If you want send me a PM with some contact info and I will see if I can help you out, I come to Stephenville every now and then on the weekends, and believe it or not I even travel through Harlingen too.

 

just make sure you get stainless flex pipe. the galvinized only lasts a couple of months

 

Its the first flange you mentioned. And its 3".

 

Aint nothing wrong or illegal with flexpipe. EVERY semi on the road today has flexpipe somewhere in its exhaust from the FACTORY.

A 4" flange is only for a 4" outlet on the turbo, u need a 3" "CTD" turbo outlet flange.

 

You can buy one piece at a time. $33.89 for the one that will go around the t case just cut off the 3" part and use the 4"

 

Probably true up there.... but no rust concerns here. I ran a 2' piece of galvanized 4" flexpipe on my truck for 3 yrs! No leaks, no rust .......
and (to answer original question) no noticable change in noise level.

RJ

 

1' of flex pipe generates the same backpressure as 10' of smooth pipe (common racing knowledge). It's a mistake to use it anywhere unless you have massive pipe size overkill.

 

Mark, that's the piece of info I was waiting for in this thrad, thought I had heard that somewhere.

 

I was thinking of using flex pipe for the section that goes over my rear axle. Would the above theory still apply at the end of the exhaust system, where the pressure is less? If so, should I go to 6" flex for that section? I too plan on making a "custom" 5" system for my truck. And it's not to save money, but to have a fun project!

BTW, I think I've seen your truck on I40 a few times (many months ago). I also live in the East Mntn's.

 

I wouldn't even use it at the end of the pipe. There is still a lot of flow even back there.

Great to hear from another east mtn. guy! What does your truck look like?

 

I'm not sure what you are calling massive, and I don't know what size others have on their trucks.... but my 4" system (turbo back) never increased EGT's or slowed spoolup when I added my 2' section (twin downpipe was to short). Twins 'released' 60 additional HP on the dyno.... which is what others found when they went to twins??

AND when I went to a 5" exhaust (downpipe back)with no flexpipe, I gained only 25-50* in lower EGT's (with no flex).

RJ