my 3" exhaust

[norm]

Just checking with you all on what I did for an exhaust. Due to $$ limits, I used straight 3" pipe to a 3" Dynomax muffler 36" long super-turbo (welded round type - nice heavy duty), and 3" tail pipe. (no "trap") I do not think it is much louder than with stock muffler if at all, and can't tell much difference in power vs. orig muffler(maybe a little). I was just wondering if I made a mistake with this muffler.
Has anyone used this? What do you think?

[Billman]

Norm

Good idea on the 'Trap'.

3" might be a bit too small. 3.5 would have been a better decision in my opinion. But price difference is big. Everybody bends/sells 3".

As long as muffler is 'See-through', it was a good decision.

[patrick m.]

i ran an exhaust similar to yours for a while, and found it did the job very well.
You probably dont need larger exhaust untill you get almost every mod availible.

(in fact, my 3inch exhaust is now on a buddy's truck) ;)

[norm]

Thanks. Further mods to my truck will not be extreme. I mainly need this truck to be reliable and last me a while. The muffler seemed alright to me, because even though it is not a "straight through" with louvers, it is very long, with a lot of volume and area through the two sections. It is a Dynomax #17789, you can check it out on their site (I got it from speedycarparts.com - free shipping!)

[Marty Lau]

Norm;
Did you replace the factory down pipe?

[CleviteKid]

According to the Dynomax Website, the 17789 muffler is good for 246 "free flow" horsepower, that is, it should not be choking off flow until you are making over 246 horsepower.

But that number is for spark ignition engines with stoichiometric fuel/air ratios. With our lean diesels flowing more gas for a given power, it might start to choke at around 200 HP or even less, if you are running high boost and low EGT.

The SuperTurbo is NOT a "see-through" muffler, after running the exhaust gas down the length of the muffler, it bends the exhaust back forward through an internal tube, and then bends it back a third time down the length of the muffler again before letting it out the back end. There are perforations and baffles inside to quiet the sound.

Dr. Lee :cool:

[norm]

No, I did not replace that ugly "what were they thinking?" downpipe... Mainly this exhaust was for the budget - and to keep it fairly quiet (I know, what am I thinking...). The performance gain over stock with trap (came out about 25% clogged) is quite noticable, however. No gauges, yet, but will likely go to pyro/boost when $, and then a chip perhaps, but the rest of my dough will probably go to just keeping it serviced well and reliable to 200K+? (now at only 111K)

[marktara]

Clevitekid, where did you get that info on the dynomax muffler. I have a dynomax 17698 on my truck and am wondering if it flows enough?

[CleviteKid]

DYNOMAX SUPERTURBO SPECS (http://www.dynomax.com/documents/super_turbo_specs.pdf) is where you can get the scoop. The 17698 flows up to 532 cfm with minimal pressure loss, and is good for 242 "free flow" horsepower with a spark ignition engine.

My system of a pair of 17770 SuperTurbos is good for 512 "free flow" horsepower in a gasser, or about 400 HP in my diesel. With no turbo, I will need to put in LOTS of nitrous and propane to hit that level. Wonder if my cylinder heads would stay on long enough to test the mufflers?

Dr. Lee :cool:

[norm]

marktara,
Interesting that the 17698 muffler came up as a "performance" option when checking some local auto parts stores that carry Walker/Dynomax. I ordered the 17789 because it was much longer (30" vs 18" body) - but it would not fit stock pipe configuration so I had a tail pipe custom made. Also for Dr. Lee: with those horsepower numbers for the Dynomax - do you have any idea how ('95ish) stock mufflers compare? Has anyone examined the GM D-max mufflers?