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holset turbo maybe twin?

C

carguy13

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so I recently aquired a holset turbo off of a fedex truck was told it had a cummins not surehis which engine or what turbo because there is no id tag on the turbo but the turbo is set at 30 psi of boost and looks to be a hx35 or similar turbo not sure. My problem is how do I get the boost down to a safe level? My other thought is can i just run twin turbos and run my factory turbo off the compressed air produced by the holset? In my head that would eliminate back pressure from the factory turbo and give you a cooler air charge and be cooler because you have twin turbos. Please give me some feedback on this either how to get the boost down or the twin turbo idea thanks for your input.
 
well to be honest I don't think the set up you are talking about would be worth it. Twin turbos in the technical sense are two separate turbos, both feeding into the engine, while a compound turbo set up is the one you are describing where one feeds into the other. To me, these set ups are better if you wanna run very high boost, so that the small charger will help spool the larger one which can produce more boost, this isn't really our goal. Also a compound set up would be very hard to fab up IMO. Also if you were to do the compound set up you would have the smaller GM-x turbo in front of the Holset, not the other way around.

maybe if you could post some pics of the turbo some of the gurus on here can held identify it???

If it is in fact a Hx-35 or something similar, just slap that turbo in place of your factory turbo and call it a day, it will be a good upgrade :)
 
with compound turbos they need to be sized to the engine and where you want to make the power among other things. you cant just install a smaller turbo and a bigger turbo and expect it to work. if you want to lower the boost you need to adjust the wastegate
 
post up some pics of the turbo. if it was off a 4 cylinder fedex truck its probably a hx30 which is a little smaller then the hx35. i dont know how it compares to a gmx turbo though. should be close in size.
 
carguy13 said:
woody- it was idle speculation.
great white- yesyou did read that correctly
Click to expand...

Interesting.

Compound turbos use the first turbo (often refered to as the atmospheric turbo) to feed the compressor of the second turbo.

I'm not sure you would get enough drive pressure out of the first compressor to drive the turbine on the second in what you're thinking. I'm thinking it wouldn't work satisfactorily, but thats just my opinion.

It would have the merit of never been tried though...at least not to my knowledge.
 
my thought on the compound turbo is if it can supply enough air to fuel an engine why cant it provide enough air to spool up a turbo and then the second turbo has cooler air running it so the air charge is cooler
 
yeah 2 tips are broken and it looks a little rough but it was free. I have a friend I'm gonna have take a look at it it might need a couple things but it should still be a lot cheaper than buying one off ebay that may need the same work anyways
 
I wouldn't use a turbo that already has broken blades.

You never know when a hard to see stress crack will let go and frag the whole engine.

Not to mention, now the compressor is out of balance. Easy for things to go wrong at 30,000-ood rpm with an out of balnace unit.

That would be one expensive "free" turbo....
 
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