HX35 and HT3B.... What down pipe?

[RSchwarzli]

Sooo, years ago the crew cab got a PDR kit that has a HX35 and HT3B. Issue is, I dont have a down pipe.

I called PDR and they were extremely rude and non helpful. Granted, I know Piers Harry isnt there anymore so the guy may not know....

Anyone know if there is anything that is available on the market for this? Anyone know what someone did for a 1st gen application?

I know the HT3B is a 5" marmon....

Thanks!

Robert

 

[mwilson]

Robert,

Do you have an existing downpipe in 4"?? Or do you want to run 5" all the way?? There are weld on 5" to 4" Marmon repair flanges for example....

Would the bends be 90 Degree on each end? There might be something in Freightliner that would work....

Give me more info.....

 

[mwilson]

For example.....Give me "B" and "C" dimensions.....

 

[RSchwarzli]

Hey Mike,

The kit itself came with a 5" marmon flanged 5" downpipe from a 2nd gen. I hacked the thing to **** and learned I wont be getting a 5" in there. So I will have to flange the 5" marmon down to a 4". Even that will be snug.

Oooooooh. Reaaaaally? A 5 to 4" flange exists? You have my attention!!

Yes. I need 90 deg as tight as possible off the turbo. I actually wonder if I need a cobra head type of pipe as it is tight as a frogs ass in there. I have to do an exact measure but I dont think I have much more than 4" between the turbo and firewall. So yes it would be flange off the turbo, immediate 90 deg down, and from there I will fabricate it into my system. If that is available, I dont care what the bottom end looks like as I will weld onto it whatever is needed.

As for B and C.... those arent really applicable in the way it sits on my truck. That second 90 is likely going to become a 30 or 45. Really the important part is how snug that first 90 off the turbo is.

Robert

 

[RSchwarzli]

Here is my sketch if it helps you visualize.

Robert

 

[mwilson]

So if you simply use a 5" weld on Marmon repair flange all would be good??? It's not like you are a stranger to fabrication work....

See page 2.7 for some examples.....

https://www.nelsongp.com/images/uploads/files/On-Hwy-Exhaust-Products-Catalog.pdf

 

[mwilson]

There are some pipes that FTL offers that do what you need at least for the 90 degree aspect with a reduction, I will tap the fertile mind of Seth when he returns from lunch......let us do some poking around...

 

[mwilson]

Found the one I was thinking of, Grand Rock makes it. May be too long but you could trim some off.


Page 46 of this catalog.......http://grpipes.com/sites/default/files/catalogs/files/GrandRock2018v2i2.pdf

 

[RSchwarzli]

Oh the fabrication work doesnt scare me. My challenge is the measurement D on that style F.... D is 4.5" between turbo and firewall on the crew. And that means that no fitsky. lol

 

[RSchwarzli]

This is almost what I need but the flange is wrong and not sure if I have room for more flange adapters or if said adapter even exists.

 

[mwilson]

Call Grand Rock directly, they think out of the box. They might be able to build it for you......there must be a Grand Rock dealer over on your side of the line that could facilitate the sale....

 

[RSchwarzli]

I will do some digging. But even if there way, they charge too much on this side of the line. Better on your side. lol

 

[mwilson]

We are having pow-wow....

Does the HT3B have a bolt on flange for the marmon pipe connection???

 

[mwilson]

Roll down this thread and see how the guy re-engineered the adapter.....

https://www.cumminsforum.com/forum/89-93-performance-parts-discussion/199041-down-pipe-twins.html

 

[RSchwarzli]

We are having pow-wow....

Does the HT3B have a bolt on flange for the marmon pipe connection???

No sadly. It is machined out of the back of the turbo. Else it would be gone. lol

 

[RSchwarzli]

Roll down this thread and see how the guy re-engineered the adapter.....

https://www.cumminsforum.com/forum/89-93-performance-parts-discussion/199041-down-pipe-twins.html

Yeah, thats what it looks like. lol And I guess a 4" will fit. You can see in that space why I was thinking the cobra head would be helpful. Yet the flange is all wrong.

Question.... in your system, does it show the specs for Cummins 3927862? As in pipe size and flange size?

 

[mwilson]

Shows the application is a "C" Series and it's for a 4" exhaust pipe.

 

[mwilson]

No joy on the flange size.....used in about 20 different engine builds for a vertical exit exhaust but I can't reverse engineer the turbo it's used on without an ESN. Cummins keeps things pretty close to the vest..

If you have a business card from a plant tour for a Cummins insider (preferably in engineering) this might be a good time to use it.....

 

[RSchwarzli]

That helps. That will likely then bolt to a Super HX40 as that is what my 1990 is running and it looks real similar and that turbo is for a C series.

Either way, that being a 4" pipe is what I needed to know. Thank you! The top end I know then would need a machined adapter.

 

[CBottomley]

Good Morning Sir
You might try if you haven't already www.dieseltuff.com. Guy name is Mark. He used to work at PDR years ago before going on his own. Anyways he set me up with Stage 1 twin turbo kit from PDR just before he left, same turbos you listed above. I bought this kit like 6 years ago. I still have it all. Hopefully next year I will install it in my 91 early truck!