jdwest

Any of you have experience with a 12cm non-wg housing on a stock H1C? I've been looking at used HX-35s...but something about buying a used turbo just doesn't sit right with me. So, what I was thinking was to go ahead and get a smaller exhaust housing and then when I get my piggy bank full (2-3 months) get the HTT IV upgrade for the H1C, if it will live that long. I was gonna stay with a non-wg housing just for simplicity's sake...and because I'd probably just plug the wg if I had one like I did on my old truck. I don't tow anything. The most I haul is a bed full of camping or rafting gear. Once again I'm looking for low end responce, mostly for in town and back country mountain road driving. I'll leave the drag racing and WOT rice grinder thumpings to more deserving trucks. As long as I keep the pump turned down until I get the turbo upgraded does anyone think I'll have a problem? Thanks again for the wealth of knowledge on this site. It's amazing what can be accomplished when we're all working tward the same goal and willing to share the info learned along the way. Now if only the rest of the world worked like this....

flashgordon

If you run a non waste gated 12cm......and turn the pump up........you will have a lot of fun....right up to the point that the turbo fins let go(from turbo over spooling or spins to fast, causing centrifugal force to destroy your turbo!)

the smallest ex housing i would consider(non waste gated) is a 16, witch you may already have!

If you don't want to go with the waste gated housing's,you can still do the HTT stage IV, witch is how many people on here have dun it!


Flash.

keithplacervill

never heard that before I was always told here that on a 5 speed without bigger injectors that it was the best houseing also the 94-99 use that housing and they can make much more fuel and ho problem with it. our turbos can handle 30 psi and that is what he would push

flashgordon

Well.......From my on experience, mine is stock except for 3/4 of a turn on the full power screw. and i when form 17 psi to 26(on a long hill)

Can't imagine what the turbo speed as well as psi would be if i remove the caller off from the power screw and turn it in 2 or 3 turn with my 16cm, let alone a non waste gated 12cm

Flash.

spunbearing

I'm not the most knowlegable guy around here by far but the 12cm2 works great on mine. I've put about 30k miles on it with no problems and I drive pretty hard. I have internal mods on my pump, timing bump, full fuel in to the collar, etc. I'm still running stock injectors though.

90firstgen

I run my turbo at 40 psi approximately. And as soon as I get my head o-ringed, I'll turn the fuel up more and hook up my wastegate. I'm gonna have it actuate at 50 psi. These H1C's can easily handle in the 30's for boost numbers. I'd still recommend getting the wastegated housing though. I could hit well over 50 psi if I had an aftermarket fuel pin so don't spend the money twice... do it right the first time!

DJ

If you use the 12 just adjust your fuel to where you get the max boost you think is safe. I never hooked up the waste gate on my 12cm, just set the fuel for 25psi. If you go to the stage 4 I'm not sure if you can controll it that much though.

Falcon1

I don't think they make a 12 non WG, but I could be wrong. Hooking the WG is easy. Get the 12 you'll like it. But now I need more air so a 16 is in my next upgrade with a hx40.

Greg

bigragu

If you want real excellent low end response, pick up a used HY35 9cm that is used in the 2001 and up automatics. Any diesel performance shop will have these sitting around because of customer turbo upgrades. My 93 W250 has this and for around town, you will leave evryone behind you once the light turns green.

gman07

Let us know how long it takes to blow it up at 50psi

You'll probably actually see cooler EGT's at 40psi than at 50, and the turbo will last longer.

90firstgen

Yeah I plan on doing some testing to see where the EGT's get too high, and where the inefficiency of the turbo starts to kill performance instead of help it with the higher boost numbers. It'll be a little trial and error for sure. EGT's don't scare me too much right now cuz I've got a few hundred degrees to play with b4 I hit absolute danger. I've also heard that higher EGT's help the air flow (as long as its in the safe range). The hotter the air, the easier it moves around and flows out the tailpipe... I'm just kind of talking to myself in that last part

gman07

Let us know how the testing goes; you should put a drive pressure gauge on and then test different wastegate settings and make a report for us. That way we can see at what boost pressure (approximately) the compressor/turbine becomes inefficient.

dpuckett

I noticed little to no improvement over a ported 18 when I went to a 12. A little better spoolup, but nothing to write home about. If you are going to tow AT ALL, I'd say go for a 16, or keep the 18 on it (by all means, if you have a 21, upgrade, though). The reason for this is drive pressure. The smaller the housing, the higher the drive pressure, esp under load. Higherdrive pressure raises EGT, which heats EVERYTHING up. The 12 cm wastegated can only support 250RWHP, according to TST, et al. Not to say you cant make more, it just isnt as efficient. I think I actually lost MPGs when I went with the 14. I'll put the 18 back on when it dries out around here, and may have the 14 for sale. I may not, either. I had good results with the PDR HX35-18 on my old 91, and got 21mpg hwy with 4.10s.

If I had an auto, planned to keep it near stock, and only drove empty, I'd consider the 12. I have not had good expereinces, or at least not GREAT experiences with them coupled to a manual.

Daniel

1stGen545

well I dont clame to know every thing but I have put 12cm on 5 trucks and they all made a night and day differance with out running to hot. please dont run over about 30psi on a H1C your wasting your time and buting unnessesery stress on it and it gets way off the compressor map. I ran my truck non/wgt with lots of pump mods and POD's and a 5spd it out ran a lot of 2nd and stock 3rd gen trucks. I used it for lots of towing ( 16,254lb man lift on a 32' tandom duel goosneck) leaving the shop was a long hill, with the stock housing I toped the hill at about 40 with the 12cm it was 55 and actualy had lower EGTs becous it made more boost and a lot faster, and you all know that more air helps to keep things cool. I know its all a trade off but I think the 12cm is one of the best thing you can use (unless you hang around a big truck junk yard and finde a HX-35 14cm/wg with 30,000 miles for free)

dpuckett

I topped 30with my nonIC 91, stock everything except fuel settings. I frequently ran 40+ psi through a PDR HX35-18. In MY experience, installing a 12cm housing was a waste of time, though it looked cool and was a bit of a selling point to prospective buyers (spools quicker than a Banks unit). If you can stay under 30psi or hook up the wastegate to 30psi, and have good results, then do it. I was just offering a differing point of view.

What semis run a HX35 of any variety?

DP