Holset H2C Turbos
Thread Starter
Junior Member
Joined: Jan 2008
Posts: 30
Likes: 0
From: Ridgeway, VA
Car: 86 IROC
Engine: Soon 355
Transmission: 700R4
Axle/Gears: 3.42
Holset H2C Turbos
Hello guys, I have two Holset H2C turbos in my garage, and I figured, I have them, why not use them?
It would be really cool to run a twin turbo setup but that may be trouble waiting to happen. I dont know anything about turbos, just basic principles on how they work, etc.
What do I have to do to get these bad boys running on my IROC? It has a 350 carburated engine. The compression is 12-1 which is way too high for a turbo, but I have a different set of heads I can use which will bring it to about 9-1.
Anyone used similar turbos?
It would be really cool to run a twin turbo setup but that may be trouble waiting to happen. I dont know anything about turbos, just basic principles on how they work, etc.
What do I have to do to get these bad boys running on my IROC? It has a 350 carburated engine. The compression is 12-1 which is way too high for a turbo, but I have a different set of heads I can use which will bring it to about 9-1.
Anyone used similar turbos?
Senior Member
Joined: May 2007
Posts: 276
Likes: 0
From: Woodbridge, NJ
Car: 85 Trans Am / 64 Chevy Nova
Engine: Turbocharged 355ci / 383ci
Transmission: WC T-5 / T10
Axle/Gears: 3.45 / 4.11
Re: Holset H2C Turbos
for twins oh yes its way to big that's why they're on single turbo diesels
Supreme Member
iTrader: (1)
Joined: Jan 2002
Posts: 4,432
Likes: 1
From: garage
Engine: 3xx ci tubo
Transmission: 4L60E & 4L80E
Re: Holset H2C Turbos
Hello guys, I have two Holset H2C turbos in my garage, and I figured, I have them, why not use them?
It would be really cool to run a twin turbo setup but that may be trouble waiting to happen. I dont know anything about turbos, just basic principles on how they work, etc.
What do I have to do to get these bad boys running on my IROC? It has a 350 carburated engine. The compression is 12-1 which is way too high for a turbo, but I have a different set of heads I can use which will bring it to about 9-1.
Anyone used similar turbos?
It would be really cool to run a twin turbo setup but that may be trouble waiting to happen. I dont know anything about turbos, just basic principles on how they work, etc.
What do I have to do to get these bad boys running on my IROC? It has a 350 carburated engine. The compression is 12-1 which is way too high for a turbo, but I have a different set of heads I can use which will bring it to about 9-1.
Anyone used similar turbos?
Member
iTrader: (1)
Joined: Sep 2003
Posts: 455
Likes: 0
Car: 1988 firebird trans am GTA
Engine: 5.7L w/hsr
Transmission: 700r4
Axle/Gears: posi 3.23
Re: Holset H2C Turbos
where would the numbers be? i have one i'm using in a single turbo build and the housing has no numbers on it i can find.
Supreme Member
iTrader: (1)
Joined: Jan 2002
Posts: 4,432
Likes: 1
From: garage
Engine: 3xx ci tubo
Transmission: 4L60E & 4L80E
Re: Holset H2C Turbos
For the compressor inducer wheel diameter you will have to cut a piece of construction paper just wide enough to fit into the inducer inlet. See picture #1 on the left of this link:
http://cgi.ebay.com/ebaymotors/CUMMI...Q5fAccessories
For the turbine numbers look at picture #3 down on the right at the link above. That turbine is marked "21".
http://cgi.ebay.com/ebaymotors/CUMMI...Q5fAccessories
For the turbine numbers look at picture #3 down on the right at the link above. That turbine is marked "21".
Member
iTrader: (1)
Joined: Sep 2003
Posts: 455
Likes: 0
Car: 1988 firebird trans am GTA
Engine: 5.7L w/hsr
Transmission: 700r4
Axle/Gears: posi 3.23
Re: Holset H2C Turbos
wow... i wish my turbine housing looked that good. that number is no longer there. i'm in the process of rebuilding it so i have it all apart.. new bearings and seals in the chra and working on cleaning up and smoothing the inlet on the turbine housing. guess i'll have to strap it in and hope its one of the good ones.
Trending Topics
Supreme Member
iTrader: (1)
Joined: Jan 2002
Posts: 4,432
Likes: 1
From: garage
Engine: 3xx ci tubo
Transmission: 4L60E & 4L80E
Re: Holset H2C Turbos
More than likely it is a 19 or a 21. Either will spool fine on a stock or mild 350ci? How much BHP are you looking for?
What distributor did you get the piston seals and bearings from? Or did you buy an ebay kit?
Did you make the comp. and exh. wheels before taking it apart?
What is the torque spec. Holset uses for the comp. wheel nut on the H2C?
What distributor did you get the piston seals and bearings from? Or did you buy an ebay kit?
Did you make the comp. and exh. wheels before taking it apart?
What is the torque spec. Holset uses for the comp. wheel nut on the H2C?
Member
iTrader: (1)
Joined: Sep 2003
Posts: 455
Likes: 0
Car: 1988 firebird trans am GTA
Engine: 5.7L w/hsr
Transmission: 700r4
Axle/Gears: posi 3.23
Re: Holset H2C Turbos
I am following the h2 series manual i downloaded (pdf). A friend of mine suggested a distributer and i asked and they hooked me up. all the parts look exactly like what i'm removing, the only thing is it didn't come with a new splash shield and the manual says to replace that.
i marked the comp wheel as the exhaust one doesn't need to come off. check out the following link for manuals and information on the holset turbo line:
http://www.holset.co.uk/mainsite/fil...%20manuals.php
i marked the comp wheel as the exhaust one doesn't need to come off. check out the following link for manuals and information on the holset turbo line:
http://www.holset.co.uk/mainsite/fil...%20manuals.php
Supreme Member
iTrader: (1)
Joined: Jan 2002
Posts: 4,432
Likes: 1
From: garage
Engine: 3xx ci tubo
Transmission: 4L60E & 4L80E
Re: Holset H2C Turbos
I am guessing you meant "heat shield" and not "splash shield". When I rebuild them I just install what they need. It is usually just new journal bearings and piston rings. Sometimes a new thrust bearing is needed. If the heat shield is good I re-use it. Keep in mind I am not a "professional turbo rebuild facility".
The biggest thing is attention to detail and cleanliness. Use picks to get the parts perfectly clean and inspect everything very closely for wear and cracks. If a wheel hit a housing I would also check the exhaust wheel for out of balance (bent).
The biggest thing is attention to detail and cleanliness. Use picks to get the parts perfectly clean and inspect everything very closely for wear and cracks. If a wheel hit a housing I would also check the exhaust wheel for out of balance (bent).
Last edited by junkcltr; Jul 4, 2009 at 08:49 PM.
Thread Starter
Junior Member
Joined: Jan 2008
Posts: 30
Likes: 0
From: Ridgeway, VA
Car: 86 IROC
Engine: Soon 355
Transmission: 700R4
Axle/Gears: 3.42
Re: Holset H2C Turbos
Hey guys, the turbos I have are both marked "22"
The inside diameter of the intake is roughly 3 3/8.
The side that goes to the manifold (or intercooler) is about 2 1/4
The inside diameter of the intake is roughly 3 3/8.
The side that goes to the manifold (or intercooler) is about 2 1/4
Supreme Member
iTrader: (1)
Joined: Jan 2002
Posts: 4,432
Likes: 1
From: garage
Engine: 3xx ci tubo
Transmission: 4L60E & 4L80E
Re: Holset H2C Turbos
The comp. inducer wheel should be in the 2" to 2 3/8" range.
Thread
Thread Starter
Forum
Replies
Last Post
New2Chevy
Engine/Drivetrain/Suspension Parts for Sale
2
Sep 28, 2015 12:35 AM





