exhaust question

[7SEC1000]

well my question is i have bought the 4 in exhaust to put on my 95 dually crew 6.5 turbo and i wondered if the cross over pipe is needed i mean the factory one is 2 in and i only see 2.25 crossovers and i saw one that was 2.5 in which really isnt all that big of a diff am i right in this way of thinking and if not please explain...thanks in advance Donnie

[sturgeon-phish]

The factory crossover is less than perfect for flow, with the crinkle bends and pipe diameter, but the gain by replacing it from what I understand is minimal.

[DennisG01]

Besides, it really doesn't matter how big the crossover is - the limiting factor is still the manifold opening. The benefit comes from it being mandrel bent and/or ceramic coated, not the actual size. But, like what was said above, minimal gains.

[winemaker]

I just ordered an exhaust system from Heath, including the crossover. It happens that my crossover needs replacing, so for me it's a moot point, but I found the picture on the HeathDiesel website showing a section of stock crossover to be telling. I'm not sure if it is typical or not, but the caption explains that the stocker is double-walled, or a pipe in a pipe. In the picture it shows the inner pipe badly crimped. If that's what a typical stock crossover looks like, I'd say it's worth replacing while you're at it.
Another consideration for myself is that I don't have fab skills or equipment, so I'm happy to get a new crossover with a bung for my pyrometer probe. Have fun.
Brett

[sturgeon-phish]

You mean like this
http://i126.photobucket.com/albums/p81/sturgeon-phish/Truck/000_0003-6.jpg

[winemaker]

Just like that! My welding buddy moved 4 hours away and the local muffler shop is a crook, so for me the new crossover is also cost-effective. Nice job, by the way.
Brett