Dual Exhaust

BigBlueV8 · May 29, 2002

Hey guys new to the forum. I have a question about the exhaust on my 1990 GMC Sierra 1500. I have Vortex cherry bomb mufflers on it right now with dynomax headers with 2.5" diamater pipe with no catalytic converters. But I have decided to take the Vortex off cause they are just to loud and don't have a good sound to them. I have just ordered 2 flowmaster 40 series 2 chamber mufflers and was wondering how you guys think this will sound and if you think and x pipe or h pipe will be needed. Thanks for your input.

SnakeEyeSS · May 29, 2002

from what I have heard from everyone that knows more than squat, YES! It makes sense to me to put an X on, better flow

BigBlueV8 · May 29, 2002

also will one affect the sound and where is the best place to put one and which do you reccomend. Thanks for the info.

Shaners · May 29, 2002

A crossover pipe will balance the the banks on the motor. It will help your truck run smoother and will more than likely generate a little more power. It will also take away some of the "raspy" sound of the straight duals.

I don't know for sure, but I would want the "x" or "H" pipe in front of the mufflers a few feet. That is the location I've seen most of them put...

SnakeEyeSS · May 29, 2002

I think in between(the cat and muffler) where the pipes would be straight normally, from what I have seen in magazine's.

SnakeEyeSS · May 29, 2002

Now I've got a question for you, didn't taking the cat off mess with the oxygen sensor?

MarkD · May 29, 2002

Reviews I have seen recommend the X pipe over the H pipe for torque. Yes, it will change the sound. I would best describe it as Mellow-er. I was told to put one as early (in the exhaust path) as possible without adding much bending to the system to reach the X.

BigBlueV8 · May 29, 2002

No taking off the cat did not mess with my o2 sensor. the truck only has one which was on the driver side manifold and the dynomax headers that i purchased had a threaded hole for the o2 sensor.

BuckMaster · June 4, 2002

Having an engineering background I do agree with the comments about x/h pipes balancing the engine's backpressure but I am hard pressed to believe that there would be any significant increase in hp or mpg. The guys at my local muffler shop also agree. I personally do not have the cross pipe. I have searched on different forums and have yet to see dyno results of before and after. It's all been speculation from what I've seen.

BigBlueV8 · June 4, 2002

Well I installed the flows without an h pipe or x pipe and they are pretty loud. I am thinking of installing a flowmaster h pipe kit just to quiet it down a bit.

BuckMaster · June 5, 2002

Well I installed the flows without an h pipe or x pipe and they are pretty loud. I am thinking of installing a flowmaster h pipe kit just to quiet it down a bit.

BigBlueV8, let me know if it quietens down the tone any when you put in your x pipe, I may want to do the same, just message/email me.

tks

GREGGO · June 7, 2002

Here is mine: ASM long tube headers; stock cats,;semi stock Y pipe; 2.5" cutouts (not in pics here); 2.5" pipes; 2.5" Magnaflow X pipe; 2- Magnaflow 1 in /1 out mufflers; dumps. This set-up is amazingly quiet until you want to get on it. This whole thing is queiter than my old complete stock front end with a Dynomax 1 in /2 out Ultraflo Welded muffler.

GREGGO · June 7, 2002

Ok, here is the cutouts that were put on later:

Greg

BuckMaster · June 7, 2002

Ok, here is the cutouts that were put on later:

Greg

Cool!

Where did you get the cut outs?

I see the wingnuts, can just hand tightening seal them completly?

What kind of gasket is that under the plate?

GREGGO · June 8, 2002

I got them at MTI, but Tbyrne (great to deal with BTW ) should be able to get them also. The gaskets re standard paper and will tear up over time, but they seal good enough. I wil be going with a differant type in the future, I'll let people know. I am looking into a brand of gasket we use at work to see if I can get the size I need.