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Holset Turbos

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Just to take some info from this thread a 2.0L spools 20 psi from a HX-35 around 3900 and a 2.3L spools hx-35/40 hybrid 23 psi at 3900, a 2.4L spools a hx-40 at 4000. It looks like that there is hardly any difference in spool time of the hx-35/40 hybrid and a full 40 on a 2.3l/2.4L.
 
Well I have kept up with this entire thread. One thing has escaped me though. So many people have complained about how the wastegate actuators do not work. Finally a picture was entered with the actuato tucked in between the housings. But there is a much more simple alternative. why not simply turn the flapper arm toward the top so that now when you push on it from the turbine side it opens. And mount the wastegate actuator off the O2 housing...right on the top front bolt. AGP has been doing this for years. I had a bolt on L2R, and a bolt on RS65, both internally gated with the actuator mounted on the back of the O2 housing. There is much more room there and it works flawlessly.

Don't understand why Bullseye doesn't do it like that or why no one else has figured it out. So I just thought I would throw that out there for anybody having problems.
 
That is a damn good idea for mounting the actuator. The problems I was haveing with the car where all 1G MAS releated. Just installed the MAFT and 3" GM MAF and it runs like a champ now. My problem now is kepting the boost below 20 PSI. The Holset actuator doesn't open until 20 PSI so it wasn't any good. I also modified a 3rd gen RX-7 actuator but for some reason it won't open until 18 lbs and still will spike to 24-28 PSI depending on what gear I'm in. The turbo is amazing. Once I get the boost to settle down and can go WOT it just pulls like a mofo. I'm running 10.5:1 AFR right now until I get the boost situation under hand and then I'm going to tune it up good and am shooting for 11.5:1 AFR and anywhere from 13-16* of timing advance. I'm going to give the T-25 actuator a try and mount it on the O2 housing as that is a very good idea. I'm hoping to be able to get it to not spike and hit 15 PSI for DD and still be able to hit 22 PSI for racing.

The spool is faster than I thought. Looking last night I was hitting 22 PSI at 3900 RPMs. When I'm cruising at 75 in 5th I just go WOT and by 3900 I'm already at 22 PSI. It's crazy fast. I'm actually thinking the TH is actually a bit on the small side. Every now and then I'm getting a little bit of compressor stall when I let off. Sounds wicked but I'm not liking it.
 
If you really want it to work nicely, get one of AGP's Billet actuators, or one of the Forge Billet actuators. AGP also has nice mounting plates that work perfect off the back of the O2 housing.
 
Do you have any pictures of how that accuator is mounted, I'm having a hard time visualizing what you mean.
=Jason-
 
Sure I have a couple pics of it.
 

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Ok I see what you mean but I don't understand how it works correctly. Do you need a special accuator? I would think that then it would be opposite so as boost increases it would push the flapper closed. I don't know maybe theres something I'm missing.
=Jason-
 
The flapper arms on these housings point down. So when you push from the compressor side, it opens the flapper by turning it counterclockwise. Now take the swing arm off, and reposition so it points upwards with the flapper door closed. Now, when you push on it from the turbine side, the flapper door opens, by turning it counterclockwise.

Its really quite simple. Just flip the swing arm towards the top. You can just see the position in my pic. the only thing special about the actuator is the length of the rod.
 
I'm going to fab me up something simular this weekend and see how it works. I'll use a stock T-25 actuator and just cut off the original bracket and weld on a new one and drill it out to fit the top and second bolt on the O2 housing. If I still have boost issues after that with it spiking to 25 PSI and then settling down to whatever the actuator is set at I'm going to have to call bullseye and have a talk. This spike is crazy. I've heard from several other people that the bullseye housing with internal gate just doesn't work. If I can't get this to work I would like to exchange it out for one that is made for a External Gate.

As I said before I also think the A/R on this TH is too small. It needs to be opened up a bit. The top end on these things is being killed, and it's also causing slight surge at cruise and Compressor stall when the throttle is closed after anything over 15 PSI.

I have stock internals, stock cams, and running 10.5:1 AFR now and it still spools to fast for my likings. Who cares about a little lag on a hugh turbo. This is just my opinion, and my thoughts. My pics of the install will be posted up here soon. I'm just lazy and having transfered them from my camera yet.
 
Are you having creep, or spike. You mentioned settling down, so I would assume you do infact mean spike. If this is the case, there is most likely a different preoblem. Spike is generally caused by your boost controller. What kind are you using? A very long vacuum line between the boost controller and wastegate actuator will also cause significant spike.

Edit: I see your using a turbo XS MBC. I had one of those years ago, and it was a boost spiking machine for me. I would switch to a good ball and spring type like the Hallman Pro.
 
Maglin said:
The spool is faster than I thought. Looking last night I was hitting 22 PSI at 3900 RPMs. When I'm cruising at 75 in 5th I just go WOT and by 3900 I'm already at 22 PSI. It's crazy fast. I'm actually thinking the TH is actually a bit on the small side. Every now and then I'm getting a little bit of compressor stall when I let off. Sounds wicked but I'm not liking it.

5TH?? When does it spool 22 psi in 2nd and 3rd?
 
I forgot to update my Profile. Opps... I have a Greddy Profec B Spec II now, but it's not hooked up anymore. I'm running about 7" of vacumme line from the compressor discharage to the wastegate actuator, so It isn't a line issue. It is boost spike. But when it spikes to 25+ PSI and takes about a second or so to come down it's very nerve racking. I'm going to try the T-25 actuator tomarrow off the O2 housing as I like that idea.

Well in 1st gear I only see about 25ish PSI and by that time it's time to shift cause it crazy fast. I honestly can't tell you where it spools at in 2nd or 3rd cause I'm only watching the boost gauge and tring to also see my WB as well. I can tell you it's around if not sooner than 3800-3900 RPM, but that is just a guess. Seems I can't tell how hard my car pulls as the adrenialin is pumping pretty good through me when I get on it. But all my buddies tell me it is the fastest car they have ever been in. I'll post back soon about the T-25 actuator and how it turns out.

Now time to change the profile.
 
Maglin said:
Well in 1st gear I only see about 25ish PSI and by that time it's time to shift cause it crazy fast. I honestly can't tell you where it spools at in 2nd or 3rd cause I'm only watching the boost gauge and tring to also see my WB as well. I can tell you it's around if not sooner than 3800-3900 RPM, but that is just a guess. Seems I can't tell how hard my car pulls as the adrenialin is pumping pretty good through me when I get on it. But all my buddies tell me it is the fastest car they have ever been in. I'll post back soon about the T-25 actuator and how it turns out.

Now time to change the profile.
Well the only reason I said anything is 5th would spool the fastest and all the lower gears would be slower.
 
What size orifice is needed in the oil sending line to restrict flow to the turbo? My turbo came with a -6 fitting. It seems like this would be too much oil for the turbo to take. Dave or anyone? Does Holset specify a restriction on the oil inlet? I know it is a non-BB turbo, but here is something I read about Garrett BBs

Ball bearing turbos require waterlines and much lower operating pressure 30psi recommended by Tial Sport and Garrett. The usual limiting orifice on the oil feed hole is .030" to achieve this on a performance engine. Tial also recommends a filter of 20 micron capacity which most oil filters have. Excessive pressure will cause bearing float and slow the turbo's spool time. This is not a condition suffered by hydrodynamic turbos which tend to be more forgiving about operating conditions.

Will the holset center just ... take it.. whatever you throw at it?
 
Yes. Lots of oil pressure. They will respond much like Garrett standard bearings, since they are pretty much the same. 2 floating journal bearings, and 360 thrust bearing. I wouldnt worry about a restrictor to lower pressure. A good way to keep a turbo from "pushing" any oil is to have a very large well flowing return line.
 
I'm not sure what other holsets are like, but my H1C has a little built in restrictor in the oil inlet on the chra.
 
Hi!
That's my Holset HX-35 setup in a GVR4, using stock Holset WGA. Here is links to photos:

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Feel free to ask questions.
 
Finally got some pics so here is what I have. Please don't dog on the one crush bend. It's only tempary and has been moved out of sight now.
 
Maglin said:
Finally got some pics so here is what I have. Please don't dog on the one crush bend. It's only tempary and has been moved out of sight now.

The flex hose extension on the water pipe was a pretty good idea. Looks like it worked well.
 
Morphius said:
The flex hose extension on the water pipe was a pretty good idea. Looks like it worked well.
It's working very well. I'm getting full flow and currently using no fans I don't overheat unless I'm sitting still for more than 5 minutes. I'll get some better shots of it up soon.
 
Maglin said:
It's working very well. I'm getting full flow and currently using no fans I don't overheat unless I'm sitting still for more than 5 minutes. I'll get some better shots of it up soon.

Please do get better pics because I'm interested how you did that. Did you replace all of the waterpipe or just that small section?
=Jason-
 
Morphius said:
The flex hose extension on the water pipe was a pretty good idea. Looks like it worked well.

I wouldn't trust a rubber hose that close to the exhaust manifold. Maybe it will work out fine, though.
 
deusxmachina said:
I wouldn't trust a rubber hose that close to the exhaust manifold. Maybe it will work out fine, though.
You could always do the same with 4 ply silicone which can handle more heat. Only time will tell about the heat. I have it as far from the exh manifold as I can get it. As soon as everthing is dialed in nicely I'm going to be wraping my exhaust manifold / turbo TH / and Downpipe with heat wrap which will take care of the radiant heat on the water pipes rubber hose. I just haven't done it yet cause I'm having to swap parts here and their and do some other modifications as small problems come up.
 
Maglin said:
Finally got some pics so here is what I have. Please don't dog on the one crush bend. It's only tempary and has been moved out of sight now.

For that waterpipe, how much of the waterpipe did you replace with the hose? Also what size hose is that, I'm thinking about doing this while I swap my engines. Have you had any problems yet with it melting or anything? thanks
=Jason-
 
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