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6.5 exhaust systems & cross overs who's are you running & why ?

Turbine Doc

Turbine Doc

Just Another Diesel Guy
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Heath's was my choice 2nd time for the truck, 1st time for the burb; as it has the 2 piece self aligning "slip-joint" configuration that makes the install any flavor of vehicle VERY easy.

My 1st on the truck was ceramic coated from Kennedy that died a premature death by me wrapping it with header wrap, wrapped/coated vs unwrapped aluminized I did not notice any difference performance wise, the aluminized ones are faring well in corrosion resistance thus far.
 
Why change from OEM you may ask ?, crawl under your truck have a look see, if you have stock and it is free of holes count your blessings, as you are getting full drive energy to the turbo, if not you ARE losing performance even little holes=lost performance.

Notice the bends, are they smooth or crinkled up in the radius, crinkle = non laminar flow which in itself is a loss but can be lived with for most 6.5s, but hidden from view with a GM style x-over is double walled construction, a few of those double walled X overs have collapsed internally and that can't be lived with.

Visually you can't tell if it's collapsed, a simple test is to run a golf ball thru it if it passes all way then you probably are not restricted in flow, what isn't known is when/if it has collapsed later down the line after passing the "golf ball test", or how would one know if the inner liner let go and cause what Hank has going on in this thread http://www.thetruckstop.us/forum/showthread.php?t=14852.

Hank is a machinist and can easily tell cast from steel, or other debris material; but it did get me to wondering the "what if" scenario when I 1st saw it.

These GM manifolds are getting some years on em now, how many times can the inner core be exercised hot-cold before cyclic fatigue takes it's toll, so performance gains aside, as a longevity insurance option to turbo health I'd be looking at a new x-over, last production for these was 2000, it's 2010 now 10+ years of thermal cycles if you have the factory one :eek:


You see in the attached photo an example of a "good" GM X-over (low miles for sale) if you really want it :D I have kept for nostalgia I guess
 

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Hi Tim,

I'm running the one from Flowmaster, as it came with both a downpipe and a crossover. Price was right. I did hit it with high-temp header paint. Seems to be holding up fine. I will say that after putting in new crossover and downpipe, and opening up the intake (with a dremel tool and a jigsaw) AND the 97+ air cleaner, the Tahoe seems to spool up really fast. My previous 0-60 before all the changes was at 11.5 seconds. It is now down to 9.5.

-Rob :)
 
Thx Rob,

I wonder how much is due to X over vs better down pipe, did you do both at same time like most of us did?

Anybody got a pic of a OEM down pipe those are VERY Scary how much they are crushed as delivered from GM
 
I have heaths cross over and it is already rusted to shit, looks like it's 20 years old.
 
Stock Downpipe

As requested.




No photos of the new one I installed, as the fenderwell is now back in :D
 
I have a Stainless Steel two piece crossover. Installed it and brazed the slip fit together, took a bunch of heat and flux to get the brazing rod to stick.

Wrapped the pipe a while back and have not looked under the wrap for a year now, may be rusted out.
 
I've got Heath's unit. Ordered along with his exhaust kit. Full winter and no issues. Noticable improvement not only in performance but with engine temps too.
 
great white said:
They were probably thinking ease of assembly during manufacture.....
Click to expand...

Agreed which is why we need to smack some sense into bean-counters and engineers that let them, or bosses that don't listen to said engineers every now and again for being so shortsighted, there is almost enuff room to have a 4" mandrel down pipe in there. And ease of assembly would not be compromised any.

Many of our problems in manufacturing world can be attributed to "cost reduction improvements" that is for another thread though.

Here is a pic borrowed from Heath's site with detail of a down pipe that has ability to breathe in it
 

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I have run the Flowmaster Kit on three trucks now. Can't beat it for 115$ with Downpipe. It is really high quality. In fact I showed Joey D a crosssection of one I cut apart(It lost an argument with a very large rock. I saw Joey's. As described. IMHO The Flowmaster is the best deal/quality out there. I woul not use anything else. The older kits, the crossover was off by like 1/16 of an inch and required a bit of muscle to get the bolts in. Studs made it much easier. The last kit I got for my Dually a few months ago fit perfect so I think they rectified it. My phone call to them may be the reason. I had called them when I ripped the one off my old 2000 K3500 and asked to buy just the crossover as the Downpipe was fine. They were great on the phone and sold me a new crossover for 60$. Great Company.
 
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