Swapping GT40 for HX35

[Raymos24]

Hey guys, I have been reading up on the holset turbos ( most of the 60+ pages) and have decided that the hx35 gives me the power and street ability I am looking for. I will include my mods list at the end and pictures of my set up. Basically I want to swap out the GT40 turbo for the HX35 because of the lag on the GT40. I am not looking for 600whp so the turbo is basically too much for me. So I wanted to know if I would be able to take out the GT40 and just swap the HX35 directly in as far as the oil lines and fitment issues go. (My GT40 has been flanged to fit on a mitsubishi manifold). Also I was thinking of going full E85 instead of the half/half mix of E85 and 93 I run now. Would I see significant gains with the HX35? Thanks for reading the long post and I'm open to any suggestions at all. Thanks again guys. Here is the list of mods and pics.

MODS LIST:

ENGINE:
complete 6-bolt engine
1g big rods
.080 over ross 10:1 compression custom made forged pistons
stock knife edged crankshaft
(all new bearings, gaskets, rings)
.080 over MLS headgasket
ARP headstuds
FP2 cams (same as 272 cams)
stock valvetrain
new timing belt and water pump
1g throttle body (has 2g tps sensor)
880cc PTE injectors
Slowboy racing high flow fuel filter and SS braided upper fuel line
stock fuel pressure regulator
NGKBPR7es spark plugs


TURBO SETUP:
Garrett GT40 turbo
stage 5 wheels
"S" compressor cover
SS oil feed line from oil filter housing
SS oil return line
Stock 2g exhaust manifold
external wastegate on the o2 housing (i think it is a 44mm wastegate)
external wastegate dump tube
full 3" exhaust no cat no muffler
Slowboy racing HUGE front mount intercooler with slowboy racing hard intercooler piping
1g stock BOV
3" intake tube
stock 2g MAF

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[1stGenTSi]

You will see much faster spool with the Holset, and yes it should bolt right on although you will need a different fitting for the oil feed. With a 10:1 CR you would be better with 100% E85. However your mod list says stock FPR so I'd assume your running something smaller than a Walbro 255 in which case you'd be running out of fuel pretty soon.

 

[Raymos24]

Thanks for the reply. I am actually running a supra pump. Getting the afpr is a definite priority right now. So would I have to buy the oil line kit from online for the Holset?

 

[Raymos24]

And I was thinking of getting 1600cc's injectors also to be able to send all that E85 .

 

[gsxtasy]

What EMS are you running?

 

[Raymos24]

I'm running DSMlink but have absolutely no idea how to tune even after like 3 months of reading. So I am probably going to have to take it somewhere to get tuned once everything is in place.

 

[doesitonall4rs]

the oil return line was a bi*** to run on my holset hx35 that i recently put into my car this past weekend. everything else was pretty straight forward. plus this thing spools mad fast im sitll on the 7.8:1 6bolt and only running 10psi right now, and i see 10psi by 3300rpm!

 

[Raymos24]

Ok sounds good. Thats the only thing I am worried about. The oil lines are going to be the hardest part of everything. Glad to hear you like the turbo, I can't wait to get mine in there.

 

[olmytsi]

I been helping you on link forums. As far as tuning, honestly, find the local dsm forum for you and find a local dsmer that can help you tune. You will learn better that way. New England has lots of fast ass dsms.

 

[Raymos24]

Oh yea you found me here too . Yea I am a member of the new england dsm forum but they don't see as many hits as here or other forums. I decided to go the way of the hx35 because I am fiending the faster spool.

 

[1gDSM4g63]

HX35 is a good turbo, but the GT40 is more equivalent to a HX40 power wise and spool just as fast as the GT30.

 

[Raymos24]

Thanks for the input. Around what rpm would the hx40 be at full boost. I think I read around 4500 on the other thread?

 

[xi Talon ix]

not too sure about the HX40 but ive personally seen 27psi at 3900 out of a HX35

 

[Raymos24]

Dang thats some good spooling . To be honest I want to get the hx35 because this gt40 is more for a track car and someone who wants to see like 600hp. I want a street car with no more than like 450whp and I think the hx35 would give me a better power curve because that gt40 needs a high revving to reach its potential.

 

[Raymos24]

So how easy/difficult has it been for you guys running the hx35 or hx40 to bolt that bad boy up? Do you think I should go right ahead and port the 2g manifold while I am at it? How much does porting usually go for?

 

[1gDSM4g63]

The BEP housing it pretty big but come from a GT40, it shouldn't be too difficult for you. And you need to port your 2g manifold or get a FP Race manifold, it'll make a huge difference.

 

[Raymos24]

I read a little more and ran into the H1c and the hx35 and I have a couple questions. The H1C seems to spool a little faster. Does the BEP housing fit this Holset too and as far as top end which one is better. Oh yea, sorry to ask so many questions, but will the H1C have more/less fitment problems than the hx35?

 

[1gDSM4g63]

No, the the H1C housing is a lot larger then the BEP housing and the reason it spools faster is because the stock Holset housing is a divided T4 housing and in order to outspool the BEP housing you'll need a twin scroll T4 manifold too.

 

[Raymos24]

Thanks for clearing that up. Thats probably more work than i want to get into .

 

[doesitonall4rs]

So how easy/difficult has it been for you guys running the hx35 or hx40 to bolt that bad boy up? Do you think I should go right ahead and port the 2g manifold while I am at it? How much does porting usually go for?

i dono about the manifold but the 02 housing ## gonna have to do some extensive porting because the exit on the BEP is 2.75, the evo3 o2 housing is 2.5, so ## gonna have to get a pretty large 02 housing or port what ever o2 housing u have!

 

[Raymos24]

So I took the intake off of the turbo to try to figure out once and for all what kind of turbo it is. No luck though, I did not see any markings or numbers. But I took a couple pictures if you guys want to chime in.

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[olmytsi]

Is that a 4 inch inlet? Looks BIG.

 

[kahl23]

You can't really tell if there are no markings on the housings. You really need to pull the turbo off and then take off the compressor cover and measure the inducer and exducer of the compressor wheel. The inducer is the smaller part that sticks out more from the CHRA, the exducer is the the overall size of the blades and their widest point. Inducer=where the air comes into contact with the blades, exducer= where the air leaves the blades, pretty straight forward. Same measurements can be made on the turbine side, but obviously the inducer and exducer are switched, i.e. the inducer will the measurement at the base of the wheel and the exducer will be at the "end" of the wheel. FWIW, I have never heard of a bolt on GT40 variant, I wasn't aware that the gt40 turbine could fit in a bolt on housing, so it may be something else. Also, it appears that you're missing a bolt on the backside of the comp housing, which might be a source of a boost leak, they have been before.
NewEngDSM.org :: Index is a great resource, there are plenty of guys on there who can help you with your tuning. It's too bad NED is closed, or else you could go up to a street night when there are plenty of other DSMers there that can take a look at your logs, see what's up with your tune, and give you some tips. Good luck!

 

[kraka]

I've never seen a GT40 compressor housing look like that, nor seen with a bolt-on housing. Either way, you will DEFINITELY like the Holset over a laggy Stage V turbine wheel garrett.

 

[Raymos24]

Thanks for the help guys. I'm just going to take the turbo off next weekend. I have to find out what this is because I want to sell it and get me a holset hx35. Thanks again guys.