twin turbo question

tltruckparts · #1 03-01-2010, 12:36 AM

alright so i decided im going to MAKE the twins work. but i got a question. i see no one sells twin kits for first gens but they all sell them for a 2nd gen. whats the difference in the two engines? is it just the manifold? and will a 2nd gen manifold bolt right onto the 1st gen head? i believe it will but i want to make sure before dropping the cash

ArizonaRedneck · #2 03-01-2010, 06:16 PM

PDR Diesel Performance: Cobra Stage 3 Twin Turbo Kit - (Super S300/HT3B)- 1991-1993 Dodge Cummins check this out and maybe there will be some information there you can use on what they did to make it work

welderboy250 · #3 03-01-2010, 08:17 PM

i think the issue is the truck not the engine. if it will fit in the hole it will definitely work on the engine. even the manifold for a 24 valve engine will bolt up its just that the ports are not shaped the same. there would be gasket overlap from both sides.

tltruckparts · #4 03-01-2010, 10:14 PM

Originally Posted by welderboy250

i think the issue is the truck not the engine. if it will fit in the hole it will definitely work on the engine. even the manifold for a 24 valve engine will bolt up its just that the ports are not shaped the same. there would be gasket overlap from both sides.

oh ok cool. so a 3 piece 2nd gen manifold and a 2nd gen kit should do me just fine then?

BC847 · #5 03-02-2010, 08:10 PM

Originally Posted by tltruckparts

and a 2nd gen kit should do me just fine then?

No.

The 1st gen and 2nd gen down-pipes are very different. One has to move the firewall a little using the 1st gen pipe. You'll have to cut a big hole in the firewall and floorboard for the 2nd gen to work.

For example: Here's the outlet of an HT3B turbocharger looking at the firewall (as seen from under the truck). That's the trans bell-housing to the left, the trans dipstick right in the daggum way, and the non-movable right frame rail to the right. . . . .

And here's after "Moving" stuff out of the way . . .

Even with getting one of the kits, you'll still have to make it fit. They are NOT a drop in kit.

tltruckparts · #6 03-02-2010, 09:57 PM

Originally Posted by BC847

No.

The 1st gen and 2nd gen down-pipes are very different. One has to move the firewall a little using the 1st gen pipe. You'll have to cut a big hole in the firewall and floorboard for the 2nd gen to work.

For example: Here's the outlet of an HT3B turbocharger looking at the firewall (as seen from under the truck). That's the trans bell-housing to the left, the trans dipstick right in the daggum way, and the non-movable right frame rail to the right. . . . .

And here's after "Moving" stuff out of the way . . .

Even with getting one of the kits, you'll still have to make it fit. They are NOT a drop in kit.

i dont think any of these problems will concern me. remember, i have a chevy truck that its in, so all my downpipes and whatnot are already fully custom. i was more worried about stuff bolting to exhaust manifolds etc. i can make it work with the room.

but to bc847, was the downpipe the only thing you had to make fit? did everything else go smoothly together with the exception of the DP? thanks for the info!

BC847 · #7 03-02-2010, 10:18 PM

Originally Posted by tltruckparts

but to bc847, was the downpipe the only thing you had to make fit? did everything else go smoothly together with the exception of the DP? thanks for the info!

If you go with the PDR kit, you'll need to fabricate some sort of support for the primary turbo. I made one from some scrap angle iron I had . ..

The same bolts that attach the oil drain line hold the turbo to the bracket and the other end is attached to the block, just behind the engine mount.

Of course you'll need to relocate your heat exchanger from the side of the block if your's is an auto.

You'll need to install a nipple in the oil pan for the primary's oil return.

Else it's pretty straight forward . . .

tower_ofpower · #8 03-02-2010, 10:57 PM

hey BC your minifold and turbo seem to sit a bit far to the back, i dont recall bobby's write up with the HX40 DP being that tight, he did how ever have to "dent" the firewall tho. so idk.... but way to post pics and make me drool bud. itd be stupid for me to put twins on with out the trans but man do i have the itch... never mind i took a closer look at the pics, the hot pipe dropped it and pushed it back. couldnt DP problems be resolved with a different hot pipe? i know it'd mean alot of fab work. but there's always a solution if you have a welder

tltruckparts · #9 03-02-2010, 11:06 PM

hey BC thanks a ton for those pictures! that helps alot. got a few questions. first is the primary oil return. is the nipple 100% necesarry or can you run like a Y piece to make the 2 returns go into the 1 port?

as for the heat exchanger, its coming all the way off, i left it on when i did my 5 speed swap, but thats just because i havent felt like taking it off yet.

the oil line return you have with the barbed nipple and the mount for the return line come with the kit, or did you have to make that as well?

i will probably go with one of diesel auto powers kits due to a cost factor.

and also, which turbo did you run for your smaller turbo? and i take it you have headstuds as well? and is o-ringing completely necesarry?

BC847 · #10 03-03-2010, 08:26 PM

Originally Posted by tower_ofpower

hey BC your minifold and turbo seem to sit a bit far to the back, i dont recall bobby's write up with the HX40 DP being that tight, he did how ever have to "dent" the firewall tho. so idk.... but way to post pics and make me drool bud. itd be stupid for me to put twins on with out the trans but man do i have the itch... never mind i took a closer look at the pics, the hot pipe dropped it and pushed it back. couldnt DP problems be resolved with a different hot pipe? i know it'd mean alot of fab work. but there's always a solution if you have a welder

The exhaust manifold is the typical ATS 12v model:

This "Cobra-Head" (See Cummins N series engines) hot-pipe allows the primary to be forward as much as possible from the firewall I think:

As such, the down pipe is still as short as possible coming off the primary (5" HT3B outlet reduced to 4", then turn down):

Originally Posted by tltruckparts

hey BC thanks a ton for those pictures! that helps alot. got a few questions. first is the primary oil return. is the nipple 100% necesarry or can you run like a Y piece to make the 2 returns go into the 1 port?
The primary sits too low to use the stock turbo oil return port for it to reliably return the primary oil without it backing up. Still, some Y the drains and report no problems.

as for the heat exchanger, its coming all the way off, i left it on when i did my 5 speed swap, but thats just because i havent felt like taking it off yet.

the oil line return you have with the barbed nipple and the mount for the return line come with the kit, or did you have to make that as well?
All the plumbing and fittings required comes with the PDR kit.

i will probably go with one of diesel auto powers kits due to a cost factor.

and also, which turbo did you run for your smaller turbo? and i take it you have headstuds as well? and is o-ringing completely necesarry?
The PDR Stage 1 kit comes with an HX35/hybrid for the secondary. I'm in the midst of replacing that with a 65/62/14 S300 (making the system a PDR stage 4). I do run A1 12mm head-studs. I had my head O-ringed for reliability purposes.

tltruckparts · #11 03-03-2010, 09:30 PM

thanks for the help i appreciate it alot. if you dont mind me asking how much did the oringing cost?

BC847 · #12 03-03-2010, 10:57 PM

The head came O-ringed by default.

tltruckparts · #13 03-03-2010, 11:00 PM

did you jsut buy it already done? ive thought about doing that but i dont have the slightest clue how much itd cost

BC847 · #14 03-04-2010, 07:03 PM

I purchased a full-tilt head from PDR. If I recall correctly, it seems an O-ring job was around $150 ~ $200. Not sure though.

**captain_stabbin** · #15 03-04-2010, 07:15 PM

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