I was browsing around and found out today that I have a WH1C instead of a HX35W. What are some differences between these two? I see both have the 12cm housing, but after that

 

Which is better bolted or clamped? and why?

 

They are functionally identical, they are just put together differently. The HX's have a snap ring that holds the compressor housing on the center section, while the WH1C (and the old H1C's on the 1st gens) use a big clamp somewhat like the clamp that holds the elbow on the compressor. There's really no "better" for our puposes, the HX-35 is just simpler (read cheaper) to manufacture.

 

Functionally identical, that is what I was hoping to hear. On htt turbo's site they had replacement compressor wheels. For the WH1C they offered a 60mm, am I correct in assuming that the bigger the wheel, the more boost? Would this also come at the cost of some lag?

 

Yes and yes. Bigger wheel=more air but also more rotating weight and more power needed to move the extra air so there will be more lag.

 

I installed the larger wheel on mine and was real unhappy with it. It pumps a lot of air on top but very difficult to spool loaded. I actually lost power towing my 10k fiver I could not get the rpms up to spool it in the higher gears it would get well over 1200* before I could get the boost up. I called piers and he said that is why they would not use the 60mm wheel he said they would only use the 58mm wheel so I called htt and traded my larger wheel for the 58 and It work real well with that.

 

I built a HX35-40 with the 60mm compressor wheel, I loved that turbo and would still be running it if I was under 350HP. I saw no increase in lag as long as you have the fuel the spin the turbo and adjust the AFC properly. The main difference between a good truck and a great truck is in the adjusting of the Pump.
Bruce

 

I was given it plenty of fuel! you probably don't live at 8000' as long as I was not loaded it worked great but pulling at 55-60 I could just not keep it spooled well enough to keep things cool

 

I don't know what RPM you tow at but I never tow under 1700 - 2000. My truck has always liked the upper RPM's for towing. That is why one of my first mods was the 3,000 RPM springs, that helped the keep the engine in it's torque range for towing. At your altitude you have problems from the thinner air that needs the RPM's up to keep the turbo spooled. A small exhaust housing helps it spin in the thin air. No I don't live at 8,000 ft. and I don't think I could drive out of the smoke at that altitude towing my 12,500# trailer.
Bruce