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Discussion Starter #1 (Edited)
Hi guys,

I'm going to be doing an exhaust mod from 3" to 4" and want to run the 4" all the way from H1C turbo outlet. I was having a heck of a time finding a 3"-4" exhaust adapter that was short enough. Like many of you I have limited room toward firewall, so I wanted a very short adapter with no long tapering transition area. Finally found one and posting it up here in case anybody wants to do the same. This one can be cut very short for a nice tight downpipe connection.

Key word in the search that helped me discover it was calling it a 'reducer' instead of an adapter, in case you're looking for some other size.

http://www.supertruckusa.com/products/77620_962.htm

JimmieD
 

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A little over a year ago I stumbled into a good deal on a brand new H1C/16cm2 housing. There was a catch of course, the turbine housing has a bolt on exhaust flange instead of the v-band flange the Dodge applications have. I ended up with a flange and a nice adapter to go straight to 4" but space is an issue. Here's the fancy transition I bought, http://www.atpturbo.com/Merchant2/merchant.mvc?Screen=PROD&Product_Code=ATP-FLS-043&Category_Code=FLS

And here's another 3" to 4" without a flange, http://www.atpturbo.com/Merchant2/merchant.mvc?Screen=PROD&Product_Code=ATP-FLS-044&Category_Code=FLS

Some of you with space issues may benefit from the turbine housings without the v-band flange provision on them, the housing is machine flat where the v-band portion is normally and drilled and tapped for exhaust components for various end users. You might gain an inch or so. The exhaust would then bolt onto the turbine housing rather than clamp.
 

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Discussion Starter #5
Those are nice but a slower transition. I needed normal steel exhaust tubing as I'm not setup to weld stainless.

This might be as good place as any for folks to post info on other trick exhaust parts that they've found?

Here's another I found but it was too long in transition to fit in the space I have:

http://store.airflo.com/4315-340-3.html
 

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This is how I did my 6BT RC...Planning a similar one for the 4BT RC.

I used to original 3" down pipe and cut the "flange" off so I have about 1.5" of 3". I cut a 4" circle from 1/4" plate(old piece of frame rail) so it would fit into the the first 4" 90deg bend. Then cut an inside circle so the 3" flange fit in to it. Took some time but worked great!





I'd be interested to hear any comments about this sort of transition versus a "conical" 3" to 4".

Andrew
 

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Discussion Starter #7
Looks like a very good idea, Andrew. The only problem I would have with it is the 4BT turbo outlet may use the V-band clamp so you can't cut the flange off. Still, a guy could use your design by cutting off the stock downpipe with a short stub left and then weld it to the 3" hole in the 4" X 1/4" plate. I just may do something similar, THANKS!

I've looked at that page I linked to again and I'm not so sure it's the right part. From the little bit of text there it seems it's some kind of clamp, like maybe the narrower 3" end gets clamped tight around a pipe. If that's the case it may be too light of a gauge of steel to use for a downpipe. May call them, but your design looks better to me, and it's virtually free!
 

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I did use just the "flange" from the D.P. Worked out fine. Honestly...This was about as "tight" as I could get with a decent radius 4" 90* elbow. Hope it works out. Let me know if you need more pics.

Andrew
 

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Discussion Starter #9
No, thanks Andrew, that's enough pictures. It's the thought that counts ha ha! I was thinking exhaust so thought in terms of tubing rather than seeing another solution such as yours. Thanks!
 

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AirFlo also has the exact 6BT exhaust pipe flange that came on the OEM Dodge Cummins. Some of the aftermarket exhausts have a cheesy flange to clamp to.

There are short and long radius bends available when planning your project, mandrel bends will be free flowing opposed to the regular bend exhaust pipe.
 

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Discussion Starter #11
Just to get the truck running and driving I dropped all the exhaust down below all crossmembers. Leaves a lot to be desired, but all the pipe was free from my donor truck! To do it right wll take some considerable planning as you mention to get all the ups and overs right. I didn't think I had clearance to run inside frame and crossmembers but now see that it will fit. Only thing that concerns me is the muffler, as some are as much as 10" in diameter. I do want low restriction and that usually means large.

Yeah, mandrel bends only!
 

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Here is my 3"-4" adapter. Also a pic of a HX35-HX40 adapter and a V band adapter for a 4" pipe. You could just get the HX35-HX40 adapter and then weld the 4" pipe adapter to your 4" pipe a 4" V band adapter and your done this is what Iam doing on my 6BT so if in the future if I upgrade my turbo to one with a 4" output the swap will be easier. Also if you made it out of S/S you could tack it and then take it to get welded in stainless if that was better for you. The 3"-4" adapter is about as simple as you can get, it is stainless but can be welded to mild. I had a stainless exhaust but was welded with mild on my chevy diesel and in 7 years had no problems at all. I am sure the doom mongers and nay sayers will chime in but I had no probs. If your exhaust is a 1 off I would recommend S/S. JMHO.

Gaza
 

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Gaza,

Where did you get those adapter,V clamp section ?
Do you have a link?

Thanks
CrewCab59
The weld on 4" V band clamp and the HX35-HX40 adapter are both fron Piers Diesel http://www.piersdiesel.com/DodgeUSPrice.htm scroll down to turbos and turbine housings. I had my 4" V band adapter bored out another 5-6mm as I didn't like the step, it now mates up to the HX35-HX40 adapter with a really smooth flow. The S/S 3"-4" reducer was from a UK pipeline shop. anymore info just ask.

Just found an interesting site with some good stuff http://www.alleghenycoupling.com/images/Allegheny Catalog.pdf

Gaza
 

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I was looking through a piping book and found something that might work. There is a long radius reducer elbow available in the 3" to 4" size. I think this was a stainless steel piece, but it may be available in steel also. The wall thickness was listed as .120". I think the center radius was 6". Piping sizes are a bit different than tubing sizes, but it would be close enough to weld up. I have not seen an actual part, only the diagram.
The only disadvantage I see to the flange reducer is the abrupt change. All of the porting work I have seen stresses smooth transitions. The flange transition will cause turbulance, disrupting flow.
 

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V-clamp

Does anyone know the dodge or cummins part number(s) for the v clamp for the flanged style turbo outlet? About how much do they cost? Where did you guys get your clamps and how much were they? I think eBay's a little overpriced...
 

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4" to 3"?

hey guys.. i've got a similar probelm, but going the other way. I dont' need 4" exhaust, but the 2004.5 HY35W/9cm turbo i bought has a 4" outlet. I have a very tight space constraint, and 4" exhaust will be hard work with.

Would a 3" reducer cause problems with the turbo?

Does anybody make a 3" 9CM housing for a Dodge HY35W? Anyone have one they want to trade for a 4"?
 

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Discussion Starter #19
Gifu I'd have to say that if there's any way possible I sure would stick with the 4" you have on that turbo. It just doesn't make sense to add in a restriction there, plus it might drive EGT's way up while also reducing performance. It's not hard to do minor mods to the firewall to pick up some clearance. Are you sure your '04.5 has an HY? I thought they used an HX or something else but I'm by no means an expert.

You might want to check but I was told the H1C and HY35 used the same exhaust side, though outlet clamp can be either style and housing sizes are various diameters.

On mine I'll probably do some more firewall work plus use some of the suggestions given by others here. According to HTT my H1C with 16cm exhaust and HTT Stage II 56cm compressor upgrade is the same as an HY35, so adding 4" exhaust will make a fairly good package.
 

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i hear you on the 4"... i would if i could... but the firewall is not easy to modify on this truck, as the a/c lines are right near that area, and to remove the dash to move a/c parts and be able to cut and weld the area... would be really really time consuming.

the earlier HY35W had a 3" outlet (circa 2002 or so), so I can't see how it would drive the EGT up that much... 'specially on a mild build.

Here is a list of Dodge turbos http://www.4btswaps.com/forum/attachment.php?attachmentid=38&d=1168021666
 
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