NA 6.5 Exhaust

[benz88]

is 4" to big? I was looking at the DiamondEye

[1988 GMC 355]

4" is not to big, that is a good size.

[benz88]

Thanks! ill be ordering one soon then.!

[1988 GMC 355]

Post some vids! is it manifold back?

[Koots]

The 4" Diamond Eye is a turbo-back exhaust, which is a downpipe and an exhaust from that.

This will make it hard to adapt to the NA 6.5 Manifolds, unfortunately.

Your best bet is to go to a muffler shop and have a 2.5" dual or 3-3.5" single exhaust system. Adapting gas exhausts from your body style of truck would probably be your only off the shelf option, and it too, would have to be cut up to match up with your manifolds.

[benz88]

Well if I got the Diamond Eye I'd cut the Downpipe section off or cut it where the ypipe merges to one.

[Koots]

The Diamond Eye system goes straight back off the turbo, one 3" downpipe, into a 4" single exhaust. So it won't fit to any manifolds and has no Y-section. It only follows down the passenger side on a 6.5TD, the drivers side exhaust manifold feeds into the passenger, the turbo is at the top and the downpipe and exhaust follows from there. It's definitely different than an NA exhaust.

The exhaust would be useable, it would just be a bit big and hard to match up with a set of manifolds. You would need to fab up a custom Y-pipe to make use of such a large exhaust as well, the stock exhaust is only 2" or max 2.25" before it merges.

It would be easier to get a turbo setup and slap it on, then run the Diamond Eye as is. It would be a badass exhaust but you would have to buy a new one if you were to ever go turbo, because it would have to be cut up and modified again to fit the downpipe section.

Not trying to $hit on you picnic, It's just the sad state of having a NA 6.2/6.5 diesel

If you want to stay NA, I can help you pick out something better for the truck. Plus some other mods to help move along better.

[benz88]

I was going to cut it where the factory Ypipe turns into 1 and weld it in there. So far the biggest non-6.5 aftermarket exhaust i've found is 3" and thats the same as the stock piping, No use it getting it.

What mods would you suggest for the NA. As I cant find turbo parts for it. Ive already moved the PMD and relocated it.

[Koots]

I would look into buying a 6.5TD crossover pipe and making a Y-pipe out of that. It can be had in 2.25" and 2.5" mandrel bent pipe and runs from one manifold to the other. The Drivers Side 6.5TD manifold (not the turbo manifold) can have a 3" collector diameter...which might make for a good manifold, but the matching set in your truck should be fine for now.

This would help supply the cut up 4" exhaust a little better. But a dual 2.5" exhaust with an H-or-X Pipe would make for a great exhaust, if you want to stay NA. The 2.25" duals in my K5 (stock exhaust) is plenty for the little 6.2 pump, but with a 6.5TD pump (detuned of course) it is hard to keep it from smoking under load.

You can even buy a mandrel bent, universal 2.5" dual exhaust kits and just cut up and weld how you need it.

That should be plenty for a non turbo diesel.

[benz88]

Thanks, Thats some stuff to look into

[Koots]

BTW, I typically hate chambered mufflers, but in the case of our diesels...they sound awesome!!

They can be had for dirt cheap too, even the flowmasters.