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Discussion Starter · #1 ·
Hello all.
Im a newby,with a few questions.
Ive been a diesel tech,since school,14 yrs now.
Anyway,long story short,im currently a owner of 2 holset/cummins turbos new.
One is a 1308384,3525700,H1C.
Other is a 802317rx,3528739.
Im in the process of trying to fit one on my 350tpi motor,but having some trouble getting the specs on these,as far as size,spool etc.
Im sure they were for 4bt/6bt engines.
Any help would be greatly appreciated,and thankx in advance.
 

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I dont know that last number, but you have several options. I will disagree with Dougal on this one.....gas turbo stuff is where I cut my teeth.

The H1C's are perfect in a pair for a 350, but you will want the smaller turbine housings. Those turbos will support 6-700HP(boost level dependent) or a little more on a gasoline engine; you can figure 100hp/lb air if everything is setup for good efficiency in the engine. If one is an HX35, you could get another of those as well. They will support closer to 900HP at higher boost levels. Another option is to build a real stump puller with one HX35. If you have an old smogger and want to wake it up without spending any real money you could build a 400HP low RPM torque monster.

Most of the junk yard guys are moving to these turbos due to high availability. The Garrett T3's have been popular and have been used succesfully up to 460cid, but they are realy just too small. The T4 family is really just right in a pair which is basically just like the H1C and HX35. The T4's have been the most popular frame for all the aftermarket stuff. The GT series are gaining popularity as well, but they are more pricey than the old T4's.
 

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Both are H1Cs

Hello all.
One is a 1308384,3525700,H1C.
Other is a 802317rx,3528739.
Im in the process of trying to fit one on my 350tpi motor,but having some trouble getting the specs on these,as far as size,spool etc.
Im sure they were for 4bt/6bt engines.
Any help would be greatly appreciated,and thankx in advance.
They are both H1C turbos..... just good examples of the many different versions of the the H1Cs that are out there.

The smaller (compressor side) 3528739 turbo has a 18cm2 turbine housing with a 41mm (inducer) x 65mm (exducer) diameter compressor side impeller.

The larger 3525700 has a 16cm2 turbine housing with a 46mm (inducer) x 83mm (exducer) diameter compressor side impeller.

Both have the same turbine shaft & wheel.
 

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The smaller of the two is probably a 4BT turbo and the larger from a first gen 6BT Cummins Dodge pickup.
If that is the case, then they are the same two turbos I have, I pulled the smaller one off and installed the larger one.
 

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Did some comp map matching on a 350 vs a Dodge ram H1C and found that a single turbo will fall off its map around 4200 rpm or so....

Gets out of the heart of the map around 3000 rpm.

I also ran the calcs assuming an intercooler and it moves the rpm numbers up, but not enough to make it worth while on that engine. A pair of H1C's would ventilate a standard block.
 

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Definately not a matched set, which is required. A pair of the large ones would work, but you will need external gates. You would be better off finding a set of HX35W's with internal gates.
 

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Discussion Starter · #11 · (Edited)
My plan is to go single,im at 340 or so hp to the flywheel,looking at 400 or so.
For what im seing is, either one would not work as they are.
Twins would be overkill,i believe for a mild smallblock.I may be wrong tho.
Another issue i got to work with is the tpi goes downhill about 4500 or so.
 

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Another issue i got to work with is the tpi goes downhill about 4500 or so.
Boost fixes that. no problem.

I went low 13's in the 1/4 mile at 105 (would have been 12's with a good 60 ft time) blowing through the stock 1-1/8" venturi 1-bbl carb on a Ford 200 cube straight six.
 

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My plan is to go single,im at 340 or so hp to the flywheel,looking at 400 or so.
For what im seing is, either one would not work as they are.
Twins would be overkill,i believe for a mild smallblock.I may be wrong tho.
Another issue i got to work with is the tpi goes downhill about 4500 or so.

Your goals and the setup are all wrong...!!

It is senseless to go through what it takes to do a turbo setup for 60HP. A set of heads, cam and some tuning will get you more than that and cost you less.

One of these is not going to work for an engine that is really already 340 HP. That is close to 1HP/cid which means you likely have higher compression ratio and more aggressive cam. What I meant by waking up a smogger was something like the 190-210HP 350's that are low compression and run out of gas at 4200RPM.

If you put a single 35 on a 340HP engine it will be all wrong. The compressor will be way off the map and the turbine will be super restrictive. Twins would be the ONLY way to go and I would want to know all the specs on the engine before I would suggest that. I know of one stock bottom end 350 churning 600HP and living through over 100 quarter mile passes. When properly tuned turbos can be very easy on an engine and will work with stock parts if you are careful.
 

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Discussion Starter · #16 ·
Great info, just what im looking for,
Just some info on my eng,
What ive done,{besides machine shop work}
030 over block,new crank,stage 2 rods,forged pistons,hardened pushrods,stock valves , dialed in hyd roller cam 214/220 452/465.ported tpi,stock heads ported,,hardened springs,worked maf,prof.done flowmatched injectors 22"s,afpr at 53psi,air intake rerouted thru my foglight holes,still on a stock prom.duel elc, fans.
By changing my heads ,ill have to change to carb,or steath intake,throttle etc.
Now,its a summer cruiser car,where i like the tpi,700r4,great off the line launch.Trans has all new internals,new pump,stage 2 shift kit,manual valve body,umi subframe connectors,and relocated lca"s,lowered 1 1/2.
Like said,its mild,any sngl turbo you think would work?Im in the process of making proms/cust tuning in which ill need to do this winter.
thanx
 

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any sngl turbo you think would work?
If you stay with the Garrett/AiResearch line, then something around T61, T62, T70 will work well, or around an H trim or better.
There are a lot of variables, and you will REALLY need to do a LOT of research on your own before you start buying stuff. What you are asking is kind of like: "how do you do brain surgery?"
It is short question that takes a long time to answer.
 

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If you stay with the Garrett/AiResearch line, then something around T61, T62, T70 will work well, or around an H trim or better.
There are a lot of variables, and you will REALLY need to do a LOT of research on your own before you start buying stuff. What you are asking is kind of like: "how do you do brain surgery?"
It is short question that takes a long time to answer.
I would also add that you want a fairly large turbine wheel, and I think P trim is a pretty decent choice on the T4, but dont take my word for it do your research.

I actually like a Holset HX40W or WH1E, which are basically the same, for what you are doing. They will be comfortable from 400-550HP. I am running the E on my 4cyl, 300cid pulling engine and it is just perfect. It is a 19cm wastegated turbine which would also work well on your engine. I can get 22psi by about 3500RPM and it holds strong to 4400(my rev limit). I have one spare on the shelf in my shop I got for $125 on ebay...it is like new. They are not popular turbos, but they are quite nice and have the map enhancement ring compressor and wastegated housing making them versatile and economical. They are basically the older version of the HX40W from what I understand. They use a different clamping arrangment on the housings, but other than that are about identical.
 

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Great info, just what im looking for,
Just some info on my eng,
What ive done,{besides machine shop work}
030 over block,new crank,stage 2 rods,forged pistons,hardened pushrods,stock valves , dialed in hyd roller cam 214/220 452/465.ported tpi,stock heads ported,,hardened springs,worked maf,prof.done flowmatched injectors 22"s,afpr at 53psi,air intake rerouted thru my foglight holes,still on a stock prom.duel elc, fans.
By changing my heads ,ill have to change to carb,or steath intake,throttle etc.
Now,its a summer cruiser car,where i like the tpi,700r4,great off the line launch.Trans has all new internals,new pump,stage 2 shift kit,manual valve body,umi subframe connectors,and relocated lca"s,lowered 1 1/2.
Like said,its mild,any sngl turbo you think would work?Im in the process of making proms/cust tuning in which ill need to do this winter.
thanx
You could run Vortec heads and a Scoggins or Edelbrock base for your TPI. That gives you the stock TPI look with the benefit of the vortec heads. That combo with stock style iron heads is supposed to be good for an honest 40hp over stock L98 heads, and the gains are much greater with aftermarket heads.
 
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