What I meant to say was just that high altitude caused the compressor to have to spin faster to make the same amount of boost. So 30psi @ sea level is fewer turbo rpm than 30psi @ high altitude.

This is because the lower air pressure/density of elevation means that the compressor is having to operate at a higher pressure ratio to make the same amount of boost (gauge pressure).

Because of this, the compressor will run off its map sooner, because it will encounter the PR limits sooner.

Agree?

 

Sorry I'm late to the party here. I never ran the 12 cm with the hybrid, but I know Swank was running an HTT stage III with a 12 cm before he built his twins (he used it as the top turbo). He lives at high altitude as well. You might want to get in touch with him and see what he has to say about how it behaved.

I think it's a good idea if the truck is mainly a daily driver/play toy. You have a good understanding of what you're doing and the compromises you are making.

 

I tried the high flow 60 mm wheel that htt offers. I had it on a 12 cm hsg I did not like it towing I could not get it to spool before my egt's where way to hot. I talked to Mark at piers and he said that is why they did not use that wheel on their turbos because you can never get "on top" of the turbo. Empty the truck was great it actually spooled a little better I figured cause it had more available air. I changed back to a 58 mm wheel and it worked better. Just my experiance with it I would like to try it again with the 14 hsg and the 215 pump I just put on and see if it would work now.

 

Justin.
I think that with Mach 4's you should be able to spool a 35/40 hybrid with a 14 housing very well, even at altitude. I don't have a wg 14 laying around, but I have a non wg 14 long housing you could try. At least that way you could see how it does without shelling out for a new housing. I ran a Dodgezilla/14 for about 6 months as a single and a year in a twin setup. It worked very well. If you ever want to try it let me know.
Ron

 

HOHN, Remeber too take into account outside barometric pressure...not sure about the yank system (sea level=29.92 inmg??) But here in the frozen north at 101.325 kPa is considered sea level. But in edmonton at roughly 2000' of elevation some days the baro pressure is 103 kPa...not much difference, but nonetheless, The air is more dense than accepted sea level pressures, thus negating the notion of "thin air"

 

one more thing, your boost guage is a bourdon tube type guage, and your boost pressures are relative too the surrounding air or baro pressure. so if outside air is at 14.7 psi, and your running 32 psi boost, then your effectivly running 46.7 psi absolute. but if outside pressure is 14 psi, and your guage reads 32, then your running 46 psi absolute.

 

Im running an HTT stage III with a wastegated 12 housing and I can say that spoolup IS slower than when compared to a stock HX35. The difference between the two is noticable up until the point where it starts making some usable boost, about 10psi or so, then it jumps up to max boost just as fast as a stocker. No scientific evidence here, just road testing.

 

Califonia trucks have the 54mm wheels all others should have 56 mm wheels..

 

HT does not have a stage IV upgrade. I called them on the rumors awhile back they said nope dont have it. The stage III upgrades all require machining to the cassette to make the wheel fit. I have the stage III with a 18 NWG. It spools okay and tows great. I do have a little more fuel than most of you guys...

 

hey hohn. just saw this on the other site. anyway, i am still running this turbo(h1c modified with mwe slot, 12cm w/ modified wg, 60mm comp wheel) in my twin set up. it's working great, and it worked great as a single. with the 54mm stock wheel, i got 75psi dp with 40psi boost. with the sixty, i would get about 47-48psi dp and 40spi boost. initial spool was noticeably slower (not by much though), but when it lit, it lit. this is all above 5000 ft too. i can't remember if i dyno'd right before or right after the turbo change, but i was sitting around 265 at that time. and the biggest difference for me was that with the stock wheel, i would hit 1600* before getting to the top of 4th. with the 60mm, i wouldn't get that hot unless i held the top of 5th. anyway, hope this helps.

dave

 

I hate to , but here is a snip of my e-mails with Paul from HTT. This is in sept. of this year.


Sorry for the late reply.
The Stage II upgrade is the 58mm housing and wheel. The Stage III is the 60mm housing and wheel. You could buy the whole turbo or just the compressor upgrade.
Let me know when you need stuff.
Thanks,
Paul
High Tech Turbo
www.htturbo.com
(801) 304-0700



Hi Paul,
Well, it's been a while, but I'm starting to get an idea of where I want my truck to be. The guys on DTR say that you have a stage IV upgrade available, but that there's a backing plate that needs to be modified in order for it to fit. Is this correct, and can I purchace a backing plate that will fit or do I need to have mine machined? I don't have a spare turbo, so I can't send it out for any length of time. I'll be running a 16cm^2 housing and an aftercooler from a late model powerstroke when all is said and done. Thanks again for your time in responding--I know you all stay pretty busy!
Greg

oh, btw, how much $$ am I looking at?

g






Hi Greg,
We can do a Stage IV upgrade for you. I can get you out a machined backplate, c. hsg, and c. wheel for the changeover. The price for all this is $285.00.
This way you can change it all over yourself and save some bucks.
Let me know how this sounds.
Paul
High Tech Turbo
www.htturbo.com
(801) 304-0700

 

Hmmm, so what's the Stage IV?

 

I think the stage IV is 62mm. Wannadiesel is running one. He'll know for sure.

 

I called him about 6 months ago on a stage IV for a HX 35 and he said NO. With NO future plans. So I guess I'll believe it when I see it....

 

It could very well be for only the H1 and WH1 turbos. Honsetly, I didn't ask about the HX, so it is entirely possible that it will never exist for an HX turbo. I know Dave is running a WH1. Maybe it has something to do with the band clamp housing vs the snap ring housing.