I have been wanting to run a Holset on my DSM for several years. Up until this point, over a decade worth of years being around DSM’s, I had mostly used TD05 or some kind of Mitsubishi frame turbo on all of my DSM’s. The first time I wanted to run a Holset was back when I had #VirginMary. She came with the factory T25. I switched to an old school turbo called a SBR2G20G and then ran an Evo III 16G. 

When I built #PoisonIvy, using most of the parts from #VirginMary, I only planned to run the 16G long enough to get the car up and running smooth. So, I built the car with the intentions of running a Holset. Life just didn’t work out the way I wanted it to and I tried living a slightly more responsible life if you will so I kept it on the backburner. Until now.

Words By: SPOOLIGAN  |  Images By: SPOOLIGAN, Extreme PSI, Justin Whitesell, eBay, Misc.


Holsets are becoming more and more popular in the DSM Community, but there still is no quick and easy direct bolt-on method. In fact, there are a ton of routes and variations to choose from. The most notable is which turbine housing to use. You can run a BEP housing to retain a DSM Flange exhaust manifold. You can run a BEP housing to utilize a T3 flange manifold. You can use the factory Holset turbine housing. You can run single scroll. You can run twin scroll. There are many many variations to choose from. In the end, it all comes down to personal preference, budget, goals, simplicity, etc. 

I was very adamant on banging this all out as quickly as possible because I am very impatient, but also because I wanted to go to The DSM Shootout with a Holset and not the 16G. The route I took was time efficient and cheap. But, I also want it to be reliable and work properly. Some areas I cheaped out on, and others I did not.  

In this article, I will go through my personal route. I will list everything I bought to put this all together and give you a brief description and other information along with each individual thing. 


PARTS LIST


The Turbo- The turbo is of course step number one. I chose the HY35 instead of the HX because the HY comes from the factory with a single scroll housing. This allows you to run the turbo with the factory housing instead of having to fork out the extra money to buy a BEP bolt-on housing just to run a single scroll setup. I bought my Holset core off of a private seller on eBay for $150. I had it shipped directly to Justin Whitesell and he completely rebuilt it and modified it for me. I HIGHLY recommend going through him for ANY turbo. The guy has been involved in the DSM Community for over a dozen years. He has helped so many of us whether it was advice, getting information about turbos, troubleshooting turbo issues, or building turbos. I won’t go to anyone else for turbo work. 

My Cost- $375 shipped after rebuild


Exhaust Manifold- There are many manifolds and tubular headers to choose from, both expensive and inexpensive. I chose the Rev9 Ebay manifold because it is cheap and has been proven to be a very reliable manifold, unlike other manifolds out there. It is also one of the shortest manifolds you can buy. Shorter manifold runners allows for a quicker turbo spool. This manifold is T3 and can be mounted directly to the factory HY housing or any T3 housing. The manifold comes with studs, nuts, washers, and lock washers. It also comes with an exhaust manifold to cylinder head gasket as well as a turbo to manifold gasket. DO NOT USE THE BOLTS. I was also recommend using better gaskets. The bolts are very cheap will will strip out easily. I ran to the hardware store and bought (4) M10x1.5 studs, (4) lock nuts, and (4) lock washers. I will be posting more information on this below this parts list.

My Cost- $117 shipped on Ebay

Direct Link- https://www.ebay.com/itm/REV9-ECLIPSE-TALON-TSI-GALANT-CAST-IRON-TURBO-MANIFOLD-T3-T3-T4-38MM-1G-2G-4G63/292038115112?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649

Part No. MF-028


Wastegate- This is one area I refused to cheap out on. From what I have seen over the years, people try to cheap out and buy a cheap wastegate, just to turn around and buy a legit wastegate anyway. I went with a Tial 2 bolt 38mm external wastegate. My wastegate came with a dump tube. You may have to source one out and figure out how you want it routed.

My Cost: $200, bought new from a private seller 


Wastegate Gasket- I bought two gaskets. One goes between the wastegate and the manifold and the other goes between my wastegate and dump tube.

My Cost- $5.50 each on Extreme PSI

Direct Link- https://www.extremepsi.com/store/product.php?productid=17654&cat=0&page=1

Part No. TL-WG38Gasket


Wastegate Valve Seat- I purchased a valve seat for my wastegate. If you buy a wastegate new, this will usually come with it. If you buy one privately, you may not get one. You need one. If you don’t use one of these, you will have a huge exhaust leak and your wastegate will not function properly.

My Cost- $14.95 from Extreme PSI

Direct Link- https://www.extremepsi.com/store/product.php?productid=19940&cat=0&page=1

Part No. TL-38VS





Oil Return Line-
I decided to build my own return line because there aren’t really any kits out there for what I needed. It is strongly advised that you use a -12AN return line. Most kits are only -10AN. This is too small and doesn’t allow for ample flow. Oil will not be able to drain as quick as it needs to which can cause a whole lot of problems. I bought 3ft. of Push Lite Race hose from Summit Racing. Your return line will only end up being around 6″ in length. Part No. FRA-803012

My Cost- $24.99 for 3ft. from Summit

Direct Link- https://www.summitracing.com/parts/fra-803012

Part No. FRA-803012


Return Line Fitting, Turbo Side- Your fittings and angles will vary depending on what manifold you are using along with many other variables. With my manifold, I needed a 30* fitting off of the turbo.

My Cost- $22.99 from Summit

Direct Link- https://www.summitracing.com/parts/fra-203012-bl

Part No. FRA-203012-BL


Return Line Fitting, Oil Pan Side-I needed a 60* fitting at the oil pan side.

My Cost- $26.99 from Summit

Direct Link- https://www.summitracing.com/parts/fra-206012-bl

Part No. FRA-206012-BL


Return Line Turbo Flange- Again, there are a few options here. I went with the more expensive, one piece design rather than the cheaper, two piece design. 

My Cost- $46.00 from Ebay

Direct Link- https://www.ebay.com/itm/S400-OIL-DRAIN-FLANGE-12-AN-BILLET/332276737756?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649


Return Line Oil Pan Bung- I am not sure if there is a -12AN bolt-on fitting for the DSM oil pan, but if there is, you shouldn’t use it over a weld-on bung. One reason is that with a weld-on bung, it cannot leak. The other reason is because you need to enlarge the hole in the pan so allow oil to flow into the pan quicker. If you do not, oil will build up as it will drain slower into the pan which will raise your oil pressure to the point it is too high and you will definitely need a restrictor. I used the AllStar Performance bung. ARP and Vibrant are a couple other companies that make them.

My Cost- $9.49 from Summit

Direct Link- https://www.summitracing.com/parts/aaf-all50774/overview/

Part No. AAF-ALL50774


Turbo Oil Feed Line-You will need a -4AN feed line to properly feed oil to your Holset. With my setup, I do not need any restrictor. You can also use an in-line filter in your feed line. My turbo came with a feed line fitting at the turbo so I bought the line and the fitting at the OFH individually. 

My Cost- $25.00 from Extreme PSI

Direct Link- https://www.extremepsi.com/store/product.php?productid=30496&cat=0&page=1https://www.summitracing.com/parts/aaf-all50774/overview/

Part No. PSI-4AN-28


Turbo Oil Feed Line OFH Fitting-You will need to feed your oil to your turbo from the OFH. The Holset requires more pressure than our TD05 turbos that generally feed from the cylinder head. You can use a 90* fitting like I did or use a straight fitting. When installed, depending on which fitting you are using, your feed line may have clearance issues with the crossmember brace. 

EDIT: I ended up not being able to use my 1990 OFH due to clearance issues with my exhaust interfering with my oil filter. I purchased and used successfully a Forward Facing Oil Filter Housing (as shown below). The threads for the feed line hole in the FFOFH are not the same as you would use in a regular OFH. The threads are 1/8″BSPT. I retapped it to 1/8″NPT and used an 1/8″NPT to 4AN adapter fitting instead of this fitting. I bought the fitting at a local machine shop so I do not have any links. You may be able to find a 1/8″BSPT to 4AN adapter fitting online to avoid retapping the hole if using a FFOFH as I had to.

My Cost- $9.95 from Extreme PSI

Direct Link- https://www.extremepsi.com/store/product.php?productid=30984&cat=0&page=1

Part No. PSI-742-04-06S-90


Turbo Oil Feed Line Turbo Fitting-I didn’t have to buy this fitting like I stated above because it came with my turbo (thanks Justin!). I just quickly looked online and couldn’t really find this exact fitting. These mostly come in some kind of kit. You can buy the kit on Extreme PSI as a full -4AN feed line kit. The fitting you will need (most Holsets) is -4AN x M12x1.5. The kit on Extreme PSI has a drop down menu for you to select from with various turbos with different thread sizes. 

My Cost- $0


Cylinder Head Feed Plug-If you were previously feeding your old turbo from the head, you need to use a bolt to plug the hole. Extreme PSI offers the perfect solution and it comes with a washer to prevent leaks. 

My Cost- $4.95 from Extreme PSI

Direct Link- https://www.extremepsi.com/store/product.php?productid=23793&cat=0&page=1

Part No. PSI-HeadPlug


Exhaust-This is something you are going to have to decide for yourself. I had been using a front bumper exhaust on #PoisonIvy with my 16G so I opted to purchase a BSFAB front bumper exit V-band exhaust. Allen at BSFAB does amazing work. I bought mine brand new off of a guy that bought this from BSFAB. He had Allen utilize a muffler in the bumper exit. Buying something that had been previously built and/or used on a Holset setup would be the simplest approach. Anything you buy, whether it is a front bumper exit or a downpipe that connects the hot side of the turbo to the rest of the exhaust will have been custom made specifically for using a Holset turbo. 

My Cost- $300 from BSFAB


Speed Density Bundle-Nearly everybody that switches to a larger turbo like a Holset also switches from MAF to Speed Density. Although, you can still use a MAF. I chose to go with a GM IAT sensor and a 4 Bar MAP sensor. If you are using a 2G intake manifold, you can buy a kit that utilizes the MDP sensor flange to bolt the IAT sensor to. This saves you from having to weld a bung for the IAT sensor to the intercooler piping like I had to do.

My Cost- $95.00 from Extreme PSI

Direct Link- https://www.extremepsi.com/store/product.php?productid=27807&cat=0&page=1

Part No. PSI-SDK-GM-A


Forward Facing Oil Filter Housing- I had to purchase and use a FFOFH due to clearance issues with my oil filter with my 1990 OFH. With my setup, my front bumper exit exhaust would not go on without interfering with the oil filter, even with the smallest possible oil filter I could find. The FFOFH is from the Mitsubishi Mighty Max/ Dodge Ram 50 trucks. There is a 6 bolt version and a 7 bolt version. This puts the oil filter facing the front and allows more room for an exhaust. Even without the oil filter on my 1990 OFH, my exhaust would not clear the oil feed line fitting on the OFH. 

My Cost- $49.00 from Extreme PSI

Direct Link- https://www.extremepsi.com/store/product.php?productid=27807&cat=0&page=1

Part No. MIT-MD122260


Non-Turbo (NA) Water Pipe- I originally thought I had one of these already. After searching for it for hours, I remembered that I sold it to a friend online that needed one in a hurry. So, I had to purchase another one. This really only applies to a 1G or at least a 1G thermostat housing. But if you are using a 2G, you still need to do something about this. From the factory, the turbo 4G63’s use a water cooled turbo. The Holset of course is not water cooled. So, you need to block this line somehow. Below in the Installation Notes, I will describe a couple things you can do to remedy this.

My Cost- $40.00 from Facebook Groups


Total Cost- $1427.30, not including most shipping, tax, and PayPal fee’s. This total cost, along with the article, will change as it is being added to. I am still in the process of swapping the Holset on. 


INSTALLATION NOTES

Again, there are a million different routes and paths to choose from when installing a Holset, or more specifically, an HY35. I am going off of my exact route with this tech article. I would like to say that the way I did things is easily one of the most efficient and cheap way to install a Holset. The manifold is probably the biggest and most important part of the puzzle. You don’t need a fancy, expensive manifold. The Rev 9 eBay manifold has been proven 100 times over with a Holset. Going to a true T3 setup is very efficient and cost effective. The HY35 allows you to use the factory housing and run a single scroll setup without using a BEP housing. The HY35 housing is the only housing out there that allows you to run a Holset in single scroll form without a BEP housing. 


The biggest hurdle in my opinion is building or buying an exhaust setup. You can buy an “O2 housing” and flex section but then tying it to your existing full exhaust will most likely require some kind of fabrication at some point. My front bumper exhaust is what, 3ft long? I still had to modify some shit. Like having to use a FFOFH. Along with it, I had to remove the front-to-back subframe brace and then I also had to grind away part of my frame/unibody in the left front in order to fit it all in there. If you have the access to a fabrication guy, or can fabricate things yourself, you can build an entire setup to fit the entire exhaust exactly how you want it and need it. But trying to make some pre-fabricated items to fit your exact car and setup will most likely require modification somewhere along the way. 


Another thing that helped me a ton was being able to mock everything up in my house on a spare long block. Doing this will allow you to dent the water pipe as needed easily, makes it a lot easier to build a return line, etc. I cannot stress how much easier mocking everything up on a spare engine it made when it came to putting the turbo in my car. I was able to completely bolt everything up, slip the manifold onto my exhaust manifold studs, and connect my return line. 


When choosing a wastegate or wastegates, do NOT cheap out. Do NOT buy eBay wastegates. I cannot tell you how many times I have seen someone try and save a couple of bucks and buy knock-off wastegates only to end up buying genuine wastegates after the fact anyway. If you want to save a little money, try buying one used or privately off of the Facebook groups or something. I spent $200 shipped for my Tial via the Facebook groups and it was never used. And it came with a dump tube. If you can’t find one with a dump tube, you will need to source one or make one. In order to use my dump tube, I had to flip the wastegate and run the dump tube out the hood (which ended up being awesome!)


If you have a 1G, you will have to cut up your front roll stop motor mount in order to gain clearance for your oil return line. This is a very very common modification when running most larger, aftermarket turbos. 


To make my return line, I only really needed a couple inches of hose after selecting my AN fittings. I used a 30* elbow on the turbo side and a 60* elbow on the oil pan side. I actually had to cut both fittings to make them shorter. Again, this is a very common thing. I cut off 2 of the 3 barbed ridges on each of my fittings. If you use the same manifold as me and do not use a spacer between the manifold and head, a 30 and a 60 will work. If you are using a different setup, you may need different angles. The important thing is to make sure both fittings added together equal 90*. 30 and a 60, 45 and a 45, a 90 and a straight, etc. 

This is also very important. You must use a 12AN return line and a 4AN feed line. If you use a smaller return line for example, you will need to use some kind of restricter in the feed line in order to slow down the oil generated from the higher oil pressure. If oil cannot exit the turbo as quickly as it needs to, it will create a higher oil pressure. If you run too high of an oil pressure, you will surely risk damaging the turbo. You will find that nobody sells a 12AN feed line, the biggest is 10AN. This is why you have to build your own. 


The OEM Mighty Max FFOFH feed line thread size is 1/8″BSPT. I did not buy a fitting online as I did with everything else. I lucked out and a machine shop at a couple of 1/8″NPT to 4AN adapter fittings so I retapped the hole in the OFH to 1/8″NPT. I bought a 90* adapter fitting and a straight adapter fitting. I ended up using the straight fitting. I haven’t looked, but you may be able to buy an 1/8″BSPT to 4AN adapter fitting online to avoid retapping the hole. Of course none of this will matter if you are able to keep your existing non-forward facing OFH. The fitting you need is listed above in the list of products I purchased. 

Installed FFOFH

You may have to slightly bend your dipstick tube in order to fit the manifold and setup into your engine. This is almost a guarantee regardless of what manifold you are using. It’s not a big deal, but worth noting in this article. 

The water pipe will be an issue and will require some modification or a replacement water pipe. The stock turbo 4G63 water pipe is set up to feed coolant to the turbo in order to cool our factory water cooled turbos. On a 1G, the coolant is fed from the water pipe to the turbo. It has a provision on the water pipe. On a 2G, the coolant is fed from a fitting that bolts directly to the the block, just beneath the water pipe. This will need to be blocked. There are many different ways to do this. Some practical and some jimmy-rigged ways. 1G guys have the feasible option to run a 1G non-turbo water pipe. This allows us to simply swap the pipe on and be done with it. But, this pipe also does not on the outlet on the end closest to the water pump that would normally go to your water cooled OFH. So if you end up being able to or want to keep your water cooled OFH, this won’t work. Not without also blocking off and/or deleting your oil cooler lines. Which is fine, it won’t hurt anything. Another decent option is to have the feed line section cut off of the 1G water pipe and welded closed. 

1G Water Pipe, Provision for the Coolant Feed

My HY35 was built by Justin Whitesell. Out of everything in this entire process, I am extremely grateful that I had him build it. He has build undoubtedly hundreds of turbos to be used on DSM’s. He had to do several modifications to ensure the turbo would fit on a 4G63. For example, grinding down part of the housing that would have normally interfered with and would have made contact with the balance shaft passage on the block. The end result was so perfect that you would be lucky to slide a piece of paper between the housing and the block. This allowed me to avoid using a spacer or do any of the modifications myself. If you are reading this, I don’t care what turbo you are using, contact Justin Whitesell and have him build your turbo. I can’t imagine the head ache I would have gotten from trying to complete this swap without having Justin build the turbo for me. 


POST INSTALL NOTES

Justin Whitesell nailed it. Everything he said about how the HY35 would perform was spot on. He told me with my manifold that I am using, which he referred me to, I would see full boost no later than 4200-4300RPM. I am seeing full boost (currently 20PSI) at 4100RPM. It pulls hard, much harder than my E316G (obviously LOL). The HY35 basically has the spool of a TD06 20G but with way more flow. Of course if you end up doing something and run a twin scroll setup, you will see a significantly quicker spool. But one thing is for sure, the HY35 in the bolt-on T3 single scroll form, there isn’t a combination out there where an HX35 will spool quicker than the HY35 as single scroll. 

I am hitting peak load right at or before 5500RPM. Below is a quick representation of my timing curve through a pull with the ignition map that is currently flashed onto my ECU. This is the same map I was using on my 16G and have been making changes to. Although, I am not seeing any knock yet, other than a couple counts, at 20PSI.

Evo III 16G on the left, HY35 on the right.

I am also currently still using my 2G MAF. I bought a 4″ to 2″ reducer coupler to attach my old intake pipe to the HY35. I still haven’t gotten my IAT bung welded onto my IC pipe yet. Once I do, then I will be tuning for SD. But the 2G MAF is performing very well still. I have thought about looking into the 2G MAF 1/4 mile record, just to prove the 2G MAF will get you very very far. Much further than most people like to believe.


This is similar to what people say about the need to have a rewired fuel pump. I am STILL running a single, UNWIRED, Walbro 255. My IDC with my PTE 1000cc. injectors with the HY35 at 20PSI is around 75%. PTE is known for not being able to flow what they are rated for. All of their injectors seem to flow about 100cc. less than what they are supposed to. I believe I can push the HY35 to run 30PSI and still not run out of fuel. My AFR is still in the low 11’s at 20PSI. If needed, I will rewire my fuel pump and/or increase my base fuel pressure. I would also like to note that my Aeromotive AFP is set to have 42.5PSI base fuel pressure, not the normal 1G 37PSI base fuel pressure. I am using an Evo 8 ECU and a 2G MAF. Both the Evo’s and the 2G’s have a base fuel pressure of 42.5, which is why I run it. Sometime after The Shootout, I will be switching to a larger injector so I can really push the HY35.

GOOD HY35 RELATED LINKS

10 Second HY35 Thread

Holset FAQ

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