Hi, I have a stock 97 5 speed 4x4. The truck is stock (and will remain so) except for BHAF. I am going to be putting 4" exhaust on it. I found the cat back on craigslist for 50.00. I'm wondering if it's of benefit to also buy the downpipe? I think the downpipe is 3.5", and given the cost of it (75-125.) I'm not sure that the benefit will justify the cost? I do haul a trailer (4.5 to 9 K), but the truck is never pushed nor does it get hot. I'm looking for mileage and temperature reduction. What do you think????

 

Temps will drop 50*-150* depending on who you ask.
If you have no plans on bombing, I guess there is no real NEED for a 4" DP.

I'd do it anyway, but thats just me.

 

Try to find a 4" cat , then do a complete system , then you will get all the benefits .

 

Just go up to the 4".

I dropped the cat out on the stock system and gained the 50-100°F EGT's and about 1-2 psi boost. Obviously mine was getting plugged. After that mine was rusting out at the muffler so I just got the whole system. I think the MBRP in the DTR store is only $480 for the aluminized 4" from the turbo out with the muffler, you would just need the '98 rear hanger for $35 as well.. Try and see what an exhaust shop would charge, I would bet double for just a 3" replacement.

It is worth the investment, especially if you tow..

 

i dont see the point in even buying a cat back to get any sort of impressive reduction. you need a full exhaust from turbo back to see real egt gains. Instead of payin extra for a just a name theres expandit exhaust kits for around 340 shipped.

 

Man you really don't like MBRP eh? Paying for the name... HEheheheh, try pricing out Magnaflow, Banks or any of the others. I would say MBRP would be well under that.

Support DTR (its a free site) and get a deal through the DTR store..

 

I agree just ditch the whole stock system, and go up to the 4". I did mine in sections like that at first and was never happy until I yanked it all off and built my 5" system. Not sure on the 97 but on my 98 the down pipe was only 3" not 3.5 so the full inch difference going to 4 would be noticeable.
If you don't mind the noise, leaving the cat and muffler off will help lower temps too. Think of it as a big air pump, the better air flows the better it runs.

 

Cats plug up.
I wouldn't even consider leaving one in the system.

 

can I jump in here.....so if I cut the cat out of my stock system I should see a gain? until a custom Is affordable.

 

Yea, you could, but with complete 4" turbo back systems on Ebay for 229-249, why?

 

The aluminized MBRP 4" system from DTR is 250 beans !
http://store.dieseltruckresource.com/mb19docualtu.html

 

I am a cheapo and I am looking for a 3rd gen complete exhaust, a little larger than 2nd gen and possibly free....

You just have to replace the flare at the begin (turbo) with your old one.

 

What cha mean "beans"?

I've decided to go 4" turbo back but I definitely gotta have a muffler, I want quiet as possible but want the performance. (so NO Magnaflow, been looking at the MBRP... but is there something quieter that doesn't decrease performance? I know its gonna be louder than my current cat/muffler system)

Looking at aluminized vs T403, can I get 10 years of service out of an aluminized?