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Exhaust ideas needed.

ellero

ellero

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Location
Covington, Georgia
The rig: 84 K5 blazer, 350ci motor, T-350 / NP203 with part time kit, new CV driveline, 35X12.5 Cooper Stt tires, stock gears.

I am having an exhaust system put on tomorrow, but not sure whats best. Should I go single or duel? Also what size pipe?

I know that I do not want the crosover tube up front in the event I change the transmission, the lift, or driveline angles in the future. My thought was to go duel exhaust to avoid that problem but some say that single is better. Would I get the same bennifet to have a crossover pipe installed at the rear of the K5 rather than the front? Someone once mentioned more power with an X-pipe. Anyone know?

The motor is still stock and may have some work done on it in the future or possible the motor may be replaced in the future with a new and more powerful one. With that said, I am hoping for some good advice from all of you who have been there and done that. Keep in mind that this system will be WITHOUT cats. Where I am moving to there is no smog or inspections and therfore I am exempt even on an 84.

Although performance is the key, lets face it, I want it to really sound good too.

John
 
i've been looking at this problem on my 82. i think small diameter (2") dual pipes with an H-pipe over the rear driveshaft could work. and i'd probably have them exit at 45 degree angles so they don't get in the way of the suspension (particularly once i do a shackle flip) and, more importantly, so that when i'm mudding, if i sink one side into a deep rut, the exhaust can still flow through the other and not kill the engine. that's another selling point on having duals with a crossover pipe of some sort. x flows better, but H is better than nothing, IMO.
 
You are in Oceanside so if you go dual you will fail the visual when you go to smog. I run a single 3" with a highflow cat and super40 and it exits behind the rear wheel. I have a post on here that I will find a link for you.

In California you have to keep the exhaust in the factory location with respect to the cat and 02 sensor. Other than that you can do what ever you want.

Ira
 
sandawgk5 said:
You are in Oceanside so if you go dual you will fail the visual when you go to smog. I run a single 3" with a highflow cat and super40 and it exits behind the rear wheel. I have a post on here that I will find a link for you.

In California you have to keep the exhaust in the factory location with respect to the cat and 02 sensor. Other than that you can do what ever you want.

Ira
Click to expand...
Thanks for the info. I am moving to GA and already have GA tags on it so smog is a thing of the past. Im not worried about any inspections anymore. Just want whats best for the truck you know?
 
ellero said:
Thanks for the info. I am moving to GA and already have GA tags on it so smog is a thing of the past. Im not worried about any inspections anymore. Just want whats best for the truck you know?
Click to expand...

Got it. I prefer a single over double as I run rocks (when I go wheelin) and it is less to get hung up on stuff and it costs less and has less hassle being routed.

I still say go with a single 3" as it will work excellent for the majority of rigs out there.

I am no expert just my opinion.

Ira
 
I am with Ira here. Single 3" is nice. Less stuff to have to worry about.
 
sandawgk5 said:
You are in Oceanside so if you go dual you will fail the visual when you go to smog. I run a single 3" with a highflow cat and super40 and it exits behind the rear wheel. I have a post on here that I will find a link for you.

In California you have to keep the exhaust in the factory location with respect to the cat and 02 sensor. Other than that you can do what ever you want.

Ira
Click to expand...
Is that really true? I have duels on my truck, I'm not requirred to have o2 or cats so that might be why but I;ve seen a lot of trucks with duals that were newer.
 
*Generally* it's the catalytic converters that drive the equation.

No trucks that I'm aware of up to 1987(91) had dual exhaust with dual catalytic converters. Since it is *federally* illegal to add or subtract from the number of converters a vehicle originally came with, really the only way to run duals in these trucks, is on ones that didn't come with catalytic converters from the factory. Anything downstream of the cat you can do whatever you want to do with it, so GM put dual tips off of the muffler on single cat trucks for a dual exhaust look. Saved them the money of adding converters, certifying yet another drivetrain combination, etc.

As to the original question, I'm with the 3" crowd. Less parts, less expense, cleaner undercarriage, short of the y-pipe.
 
ellero said:
Thanks for the info. I am moving to GA and already have GA tags on it so smog is a thing of the past. Im not worried about any inspections anymore. Just want whats best for the truck you know?
Click to expand...

Look into that smog thing further brother. i live in Hall Country in GA and we dont have emissions testing, but all the counties around Atlanta do, and I'm not sure what others... In Hall, we dont even have safety inspections.
 
I run dual 2 1/2 with flowmasters and headmans on my pickup. I had to cut them under the bed to fit the hitch, but i like it better now. The fumes stay out and it sits high by the frame. My brother did the same with his 79 k5, but he used cherry bombs and stock manifolds. This allowed him to keep everything between the frame and it helped with the fume. It's also much cheaper. Oh and neither of us run x-overs.
 
It'll still flunk the state safety inspection if it doesn't have all the original type smog control equipment on it or evidence of EPA recertification, even if there's no requirement for a tailpipe gas test.
 
If your motor is stock with only mild peformance parts planned, a single 3" would be plenty. If you anticipate more mods down the road, headers and dual 2.25-2.5 is probably good with some sort of balance. Xpipes are damn near impossible to put in the correct location on our rigs while still keeping the pipes up out of the way. H pipes are much easier but not quite as effective as x pipes.

IIRC I read exhaust should flow 1.5X the CFM rating of your carb. Might have been 2X, not 100% sure. You can google for flow rates of different sizes of tubing. that'll get you in the ball park at least.
 
Well I went with the majority and did the single 3 inch with a "Y" pipe. I had my exhaust guy make the "Y" conection in front of the muffler and the crossover pipe is under the T-case, just before the output shaft so that I lose no ground clearance and it also does not interfere with either drivline. It is also flanged so that I can remove it easy for future maintenance. I will try and get a few pictures of it as I think it turned out great.
 
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