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View Full Version : TIII Holset HX35 project.



Tony Hanna
06-18-2007, 08:00 PM
I've been at this for awhile now, but I've finally got about everything I need gathered up, so I thought I'd start posting pics.
Here are some random ones of parts, and one of the turbo on the car.

RJ138
06-18-2007, 09:09 PM
Nice! Did you weld a bracket for the wastegate on the compressor housing? Looks good!

Did you have really bad fitment issues with the compressor housing? With the Hybrids you can usually get away with just grinding down the little ear of the tranny that it hits.

Just curious as I have a Holset waiting to go on.:evil:

Tony Hanna
06-18-2007, 09:25 PM
I had a friend weld it. He does good work.:)
I'm using the stock Holset turbine housing, so in addition to grinding the ear off of the trans, I had to run a 3/8" spacer between the turbo and the manifold. You can see it in the picture. Also I had to rework the shifter cable bracket to drop the selector cable, and cut the stud and a little bit of the nut off of the bobble strut. That's all I've run into so far, but it's still a good way from being ready to fire up.

2.216VTurbo
06-18-2007, 11:52 PM
Tony, you have GOT to be single, no way any wife would tolerate turbochargers on the furniture:lol: Man I washed some 'sort of greasy' parts in the kitchen sink ONCE:o I thought I had cleaned it all up:( ...

Tony Hanna
06-18-2007, 11:58 PM
Not single, just extremely lucky.:thumb:
Tiff's really easy going about stuff like that. Plus it doesn't hurt that the chair is from my old place and in rough shape to start with.:)

87glhs232
06-19-2007, 12:03 AM
LOL, I was going to comment about that as well. Figures its an old chair, my guess is she wouldn't have picked that fabric :faint:

:focus: Nice parts and work you have there!

Darkwolf
06-19-2007, 12:54 AM
LOL, I was going to comment about that as well. Figures its an old chair, my guess is she wouldn't have picked that fabric :faint:


1983 was a good year ;). Hurry up man I want to go to the track.

Tony Hanna
06-19-2007, 01:13 AM
LOL, I was going to comment about that as well. Figures its an old chair, my guess is she wouldn't have picked that fabric :faint:

:focus: Nice parts and work you have there!

I don't know... I have the absolute ugliest couch in existance. The pattern is 70's I mean straight out of Fear and Loathing. I was going to haul it to the dump when we got this place, but she was having none of it. "I don't care what it looks like. It's comfortable so it stays!":lol:


1983 was a good year ;). Hurry up man I want to go to the track.
Me too, but I'm having a hard time finding motivation. It was too hot to mess with it today. Here in a few I'm gonna run the the 24hr parts store (I still can't get over that! We have a freaking 24hr parts store!!) and pick up some bolts and fittings. Hopefully I can get a fair bit accomplished tonight/morning and then sleep when it starts getting hot.:thumb:

Tony Hanna
06-19-2007, 09:03 PM
A little update on the project. I got the divider in the turbine housing cut back and knife edged today. I also drilled a hole through the divider directly opposite the wastegate hole to help the pressure equalize when the wastegate is open. Hopefully that will kill any possible boost creep issues.
I picked up most of the small parts I'll need when I went to the parts store last night, including a fitting for the oil feed line. I'm going to start on that later this evening. I still need to pick up an O2 sensor bung to weld in the downpipe and a new stud for the exhaust manifold. The old one spun out of the manifold and is "trapped" on the old turbine housing by the nut.

Anybody know what size those studs are? I may run by the parts store again tonight and see about picking up a bolt I can cut off and use as a replacement.
Thanks,
Tony

Tony Hanna
06-24-2007, 08:41 PM
Well, it's alive! I don't have any real data on when it starts making boost because well... there's no boost gauge in the car yet.:o
That's tomorrow's project as well as running it by an exhaust shop to get the downpipe John and I made connected to the exhaust. Just by feel, it seems as though it's going to spool pretty late. The assometer says it starts making decent boost by about 5k. That's a little (about 1000 rpm) later than what I was hoping for, but that could be due to any number of things. I'll know more tomorrow.
One thing I can say, with the HX35 and open downpipe, it sounds like a freaking road tractor.:D

Will Martin
06-24-2007, 10:00 PM
Time to advance the cam timing. ;)

Tony Hanna
06-24-2007, 11:09 PM
Time to advance the cam timing. ;)

Yeah, I should probably invest in a set of adjustable gears. I may put the timing belt off until I can afford to do it and the gears at the same time.:thumb:
Another thought that had crossed my mind was to fool with the cal and set it up to pull a bunch of ignition timing between 0" of vac and about 5 psi. That should help it spool a little quicker too. I've got some ideas I want to try, but they'll have to wait until I have the money. At least it's back together and drivable now.:thumb:

Tony Hanna
06-26-2007, 01:28 PM
Another little update on the project.
Got a boost gauge installed so I can see what's going on. Onset of boost (2 psi) happens at about 3,000 RPM, and it climbs to 7 psi by 4,000 and holds 7 through the rest of the RPM range. I'm hoping I can get that up to 10 psi by 4,000 by fooling with wastegate preload and mbc. That'll be enough for now as I'm still running the stock fuel system. Keep in mind it's also still breathing through the stock exhaust system minus the cat.

I'm real tempted to go for a quick blast with the wastegate line unhooked and the preload cranked up to see what the best case for spoolup would be, but I'm not sure if I'm comfortable relying on cutout to save the engine if I don't lift off of the throttle quick enough.
Any thoughts on that?
Thanks,
Tony

Darkapollo
06-26-2007, 03:05 PM
Id say let off by 5500 and you should be fine if the cut off fails.
Thats what I was doing when my tona wasnt tuned. Just to make sure there was nothing about to POP on the way to redline.

Tony Hanna
06-26-2007, 03:47 PM
Well, I gave it a try. Boost builds slow enough with the big turbine housing that it's pretty easy to control. With the vac. line off the wastegate, it just does make 10 psi a little above 4000 RPM in second gear. I didn't push it any past that because of road conditions.

I'm not really happy or disappointed with the way it acts. It's about what I expected and was told to expect by others. I'm sure it would act much better with a ported head, nice FMIC, a full 3" exhaust, and some tweaks to the cal and timing to improve spoolup. I plan on doing that eventually, but even then, I doubt it will ever be a very street friendly turbo without swapping turbine housings.

From my limited experience so far, my advice to anybody considering using an HX35 on a stock to mild street car is to do yourself a favor and spend the money on a Bullseye turbine housing.

Tony

Tony Hanna
06-30-2007, 06:59 PM
I've got it back apart now to try another idea. Since this is a divided tang housing and is obviously too big, I'm going to try blocking off the side of the turbine housing closest to the center section. I've been reading a thread on another board where others have tried this, and the results look promising. This should cause much quicker spoolup at the expense of a little more backpressure. How much backpressure remains to be seen. My main concern is that the internal wastegate might be a little too small for the effectively smaller turbine housing. With that in mind, I think I'm going to try to transplant the larger wastegate puck from the TIII and open the hole to match.
Hopefully I'll have the housing sorted out tonight and the car back together with some results to post by tomorrow evening.

Tony Hanna
06-30-2007, 10:28 PM
Well, I didn't get done, but I did manage to get a good start on things.
I got a 3/8" thick blanking slug made and fit up. I just need to get it welded in. Here's a pic of the slug. Everything looks alot rougher and rustier in the pic for some reason (the slug is freshly ground and shiny). It's also kind of hard to tell from the pic, but the slug is on an angle from the side of the flange down to the divider in the middle. Once it's welded, I plan on smoothing everything up for a nice transition into the open side.

RJ138
07-01-2007, 10:46 AM
Nice! I'm curious how it will work out.:thumb:

2.216VTurbo
07-01-2007, 11:09 AM
I'm not sure I follow the theory how reduced inlet size is going to help if the total scroll volume stays the same:confused: Sure velocity at that point of the inlet will go up, but will it stay higher into the scroll? Or is that the point of the trial?:o

Millerman340
07-01-2007, 11:37 AM
Well it's said that the split scroll is .55 a/r per side (Not by me) , so if you use only 1 side :blah:

Millerman340
07-01-2007, 11:41 AM
Cut from another forum ....you could actually measure the a/r if you wanted all youd need is a caliper and some way to measure the inside of the housing...caliper etc...here is a pic to kind of describe what I'm talking about


now that you understand this i can explain a lil more in detail...

the stock 12cm housing is what we referred to as a divided housing...where you could use the exh pulses to actually help spool up the turbo faster than just the exh gas pressure...this is often referred to as a split scroll turbo...hence the split in the turbine housing...now w/ the housing intact the a/r is around .55 , now if you were to grind out the divider and increase the area obviously the a/r ratio is going to increase...hence why when you grind out the divider the a/r is approx .63

now w/ the bullseye housing its a .55 housing that isn't divided....so there is no restriction of the gas pulses hittin it if you were to run a undivided manifold...and you dont have to grind out the divider and increase you a/r...also bullseye had internal wgs that you can add on to their housings making it a good setup as a whole...i still run an external gate...but if space was a concern...the internal gate would be an option...

now remeber when you decrease a/r....spool will be lower in comparison to engine speed...as when you increase a/r...spool will be higher in engine speeds....the problem is if you go to small on a a/r it will choke down the flow of the whole system...so a balance of both worlds is what you shootin for for an street car....whereas a drag car you could neglect the spool losses for increased power potential...and just build the car for the higher powerband

2.216VTurbo
07-01-2007, 11:42 AM
Well it's said that the split scroll is .55 a/r per side (Not by me) , so if you use only 1 side :blah:


Oh, it stays spilt through the entire housing?? Showing my lack of experience on the HX series:o ...

Tony Hanna
07-01-2007, 01:47 PM
Oh, it stays spilt through the entire housing?? Showing my lack of experience on the HX series:o ...

Exactly. The two sides are divided all the way to the turbine wheel. It helps if you think of a divided tang housing as 2 seperate housings within a common casting and acting on the same wheel.:thumb:
Here's a thread where the idea is covered in-depth, and several people try it. One of the guys even uses a custom header and external wastegate to valve one side open and closed. Neat stuff.

http://www.theturboforums.com/smf/index.php?topic=45148.0

Tony Hanna
07-01-2007, 05:56 PM
Here's the finished product. I welded the blanking slug into the turbine housing with a 99% nickel electrode. My photo skills leave something to be desired. It looks alot nicer in person with a nice smooth transition.
I'm getting ready to begin reasembly now, so I should have some results by later tonight or tomorrow afternoon.

TurboGLH
07-01-2007, 06:33 PM
Here's the finished product. I welded the blanking slug into the turbine housing with a 99% nickel electrode. My photo skills leave something to be desired. It looks alot nicer in person with a nice smooth transition.
I'm getting ready to begin reasembly now, so I should have some results by later tonight or tomorrow afternoon.

Didn't you drill through the divider at the WG puck to help with wg control? If so, how are you planning to plug that hole?

Tony Hanna
07-01-2007, 07:09 PM
Didn't you drill through the divider at the WG puck to help with wg control? If so, how are you planning to plug that hole?

I did, but it's a small hole (1/2"), so I'm just going to leave it alone for now. I'm guessing that 1/2 of the housing is going to be a little small anyway, so I'm hoping a little bleedover won't have much of an effect. If it does present a problem, I'll pull it back off next weekend, tap the hole, install a plug a little below flush, and then tack it in place.:)

edit: Almost there! Another 1/2 hour or so and it should be ready to fire.:thumb:

Tony Hanna
07-01-2007, 08:31 PM
Well, it's back together and tested. Here are some thoughts from the initial test run:

Cliff Notes version:
Hello torque, throttle response, and part throttle boost. I'm glad you're back, I really missed you guys!

Long version:
It's a whole different turbo! And I mean that in the best way possible. Boost onset in 3rd gear went from above 3,000 to just above 2,500. Past that point, the needle on the boost gauge climbs quickly to target boost instead of the lazy crawl that I was seeing before. The car also feels alot more responsive and I'm able to build boost in 1st and second gear and also at part throttle (part throttle boost was nonexistant before). I haven't had it on the interstate yet to wind it out and see how much of an issue boost creep is going to be, but the smallish internal gate seems to be doing fine in the lower gears.
I'll post more as I drive it over the next few days and see how it's going to act under different conditions.

Tony Hanna
07-03-2007, 03:10 AM
Another little update:
Had it on the 4 lane for some high RPM runs to check for boost creep. Doesn't seem to be a problem.
I am noticing an odd occurrence though. Boost will shoot up to 10 psi pretty quickly and hold steady there for a little bit, then it will jump (not creep) to 12 and hold 12 to redline.
I'm not sure what's causing that, but I suspect it has something to do with the hole in the divider across from the wastegate. Since I'd like to check to see how my welds are holding up now that it's got some driving time on it, I think I'm going to pull it back apart tomorrow and plug that hole while I'm at it.

8valves
07-03-2007, 09:15 AM
Pretty neat findings. Good stuff!

Tony Hanna
07-05-2007, 02:06 AM
Thanks Aaron!

I went ahead and pulled the turbo yesterday evening and got the hole tapped and plugged, then filed the plug down flush. Also, while I had it apart, I swapped the larger wastegate puck from the stock turbo onto the Holset and ported the crap out of the hole. I wasn't seeing any boost creep, but it seemed like something worth doing while it was apart.
I got the car back together this evening and test drove it to check everything out. Unfortunately the tach needle has taken to hanging up, so I don't have any hard data on the effects of plugging the hole, but it feels like it may have helped some. Boost climbs straight to 12 psi now without pausing at 10 like it was before. I'm going to try to get the tach sorted out tomorrow so I can post some accurate numbers.

Here are a couple pictures from last night. The first two show the housing before and after opening the wastegate hole. You can also see the plug through the hole. The 3rd pic is a size comparison of the Holset puck and the stock TIII puck.

Tony Hanna
07-07-2007, 12:58 AM
Ok, I've got some fairly accurate final numbers. In 3rd gear rolling into WOT from 2000 RPM, boost onset happens at 2500, and it's all in (12 psi with the g-valve) by 3500.
I'm pleased with the results especially considering everything else is stock. I'm really curious to see how it's going to act once I get the exhaust, intercooler, and fuel system upgraded so I can run some more boost. That's going to have to wait awhile though.

I've got alot of time invested in this project, but not that much money. I didn't keep track or save recepits, but I'll try to give an accurate breakdown.

Low milage take-off HX35: $100
T3 Flange (spacer): $15
3" SS flex pipe: $35
cone filter: $20
Misc. hardware (est.): $50
exhaust work (downpipe to exhaust system): $35
discharge elbow: free (thanks Craig!!)
discharge plate: free (thanks John!!!)
Aluminum welding (compressor outlet & w/g can mount): free (thanks John!!!)
Everything else I had laying around.

Grand Total: $255