How much change in power going from a stock inlet to an HTT Stage IV? What is the boost difference?

 

You probably won't gain much power from just swapping to a Stage IV unless you're fairly overfueled. Mine felt like it gained maybe 10hp, but it could be in my head. It hazed at 32psi before the Stage IV; the upgrade cleared the haze and upped boost to around 40psi. The most important part: EGT's were down slightly, and it sounds great

 

I just installed a Stage 4 compressor. I think I got a couple psi more boost with it. I had some smoke at WOT with the stock comp. and that went away with the Stage 4. My EGT went down a little also. What I noticed the most is that after the comp. swap my middrange boost and response is so much better. I love the Stage 4. The problem now is that I want bigger injectors.

Dean

 

What injectors are you running now? I didn't see it in your Sig.

 

Stock injectors for now. I did notice that I am getting more boost than before. Now I get 31 lbs peak boost. It was 25 or so. I don't know if that is from the colder temps or what. I did turn the pump up 1/4 turn though.

Dean

 

Turning the pump up will account for most of the gain, though, once spooled, the bigger wheel will push more air for a given RPM, and, all else being the same, will result in more boost.

 

I hope more efficient boost. I hope the new StageIV also has MAP slots, because I don't want to break another shaft!

Any thoughts on how much boost I can produce with this upgrade before it looses efficiency?

 

I wouldn't run it over 40 psi for durability reasons.

 

Durability of the turbo or drivetrain or what?

 

no the durability of the turbo. you have half a weak old HX40 once you go stage 4

 

I don't mean to be dense, but what do you mean?

 

An Hx 40 is comprised of a cold side/compressor that is 60cm blade, the same things as a stage IV htt upgrade.

 

So are you saying I am wasting my money? I did blow up my turbo, but it had 312,000 miles on it, and I haven't been kind to it, especially bearing in mind that I have probably been over speeding the crap out of it up at this altitude.

I believe the stage III has a 60 also, but with 8 fins. The Stage 4 had 6 fins. I think the tolerances are much better on the HTT stuff than on the stock Holeset Hx40.

Could be wrong though....

 

no no waste of money at all, but start comparing your turbo to an HX 40 when you go stage IV. Hx40's have lost popularity because people pushed them up and beyond 40 and the shaft is the same size as a baby h1c. bigger wheels on both ends on the hx 40 but has the same shaft as the baby h1c even. All I am saying is that in agreement with Wanna, don't push the turbo above 40 psi with the stage IV htt for durability reasons. There are other turbos out there with bigger shafts made to handle those higher pressures. I.e. phat shaft, sled puller, hx55 et al

the h1c is a great platform if used under spec power and stay within the map efficiency, hx 40 wheel or not.

 

How do I keep the boost under 40? (I mean, besides the obvious). I guess I could advance the pump more, but I like it where it is.
I could make a wastegate, but that would be a pain. Will the water/Meth injection do anything to lower the manifold pressure?