[JimmieD]

Hi guys!

Well, I'm doing it: just swapping out the compressor & impeller on my Holset. I've heard mention on 6BT forums about a 'silencer ring' that can be removed. I don't see any such animal!?? Does the stock CPL858 4BT H1C use this silencer ring? Thanks!

Impeller shaft has a wee bit of play side to side, none in thrust, but that will have to wait until next time. Also some carbon on inside back of impeller/compresor housing and back of impeller. Doubt it should be there....?

Oh, another thing: The HTT kit came with a flange gasket, plus a small O-ring, about 1/2" I.D.. Is this something I need to change somewhere, like to stop this exhaust carbon leak?

 

[JimmieD]

Found out the silencer ring is an option on Chrysler Corp installations, at the request of Dodge. It quiets down the high pitched whine and isn't used on all turbos. Removing outlet tube to intake manifold you can peek in the compressor hole and see the silencer ring held in with a snap ring. It's pretty obvious to see. My non-Dodge H1C of course didn't have one, and assumably most bread trucks will not.

A little concerned about exhaust side. I notice the exhaust impeller will drag ever so slightly on the housing, but this may be because the compressor side is removed. Hope so, that re-installing compressor impeller pulls exhaust impeller out of contact with housing. A very slight side play in shaft, couple of thous', but no play in thrust forward/reverse. When I shut down I can hear the turbo keep spinning for quite a while, at least 30 secnds, so probably good to go! Overall looks good, maybe rebuild in a year or ten haha!

Great opportunity to clean up some of the crud on side of engine that I can't get to with turbo installed. And for others considering a compressor upgrade, boys, it's dumb easy, just like Carl Donica said it would be! Challenge factor of about 1-1.5. If you can change spark plugs, hopefully on a gasser, you can do this swap in no time. 30 minute job if I didn't stop to wipey-cleany.

 

[JimmieD]

'Scuse me for talking to myself but I'll finish the epic:

Got the HTT Turbo Stage II upgrade done. I wanted this level as I originally intended lots of towing. This is supposed to provide better torque, and bottom end to midrange power. According to HTT it effectively makes my H1C with 16cm2 exhaust into a HY35, with the new 56cm2 compressor & impeller. My engine is entirely stock otherwise.

It was very simple to swap, but these Stage II are no longer available. All others, Stage III on up, require some machining of the housing for the new impeller to fit or somesuch thing, according to HTT.

My results were more boost low down, more midrange and more top end. I picked up 6-8 lbs boost at light throttle, as compared to none to 3-4 lbs, and midrange it built up higer sooner, and top end is at least 8-10 lbs more. Ran out of road, but 5th gear was at 20lbs, above the old number of maybe 12-14.

Overall much quicker boost, no turbo lag, smoother more powerful acceleration, better lugging power, engine runs noticeably smoother, and better power throughout the engine's range. Should be interesting when I install the #366 3,200 rpm governor spring and twist the screws some. I'm sure the boost will get past mid 20's then. From the way engine feels I expect better mileage, even though I already get 30+ mpg!

 

[BobS]

Thanks for sharing Jimmie. I for one am curious about your MPG's average after this modification. BTW, it's not the guy who is talking to himself that is crazy, it's the guy who is just standing there not listening to him that is crazy. Ha ha!

 

[JimmieD]

Hah, yeah, Bobster, there's still hope. What really helps is to look back in history at all the known wackos: the nut cases that said a wheeled vehicle could ever exceed 20 mph, the idiots that said man could fly, the screwballs that actually believed they could make a boat that men could go underwater and still breath, etc.

Unfortunately I take few 'road trips' lately, only having one estimate since I built the truck, and that coming in at 30+mpg in heavy winds. Seat of the pants says maybe 10% improvement, maynbe more? We'll see.

 

[Carl Donica]

JimmieD,(tear), I almost feel like a proud papa (tear). Ha Ha, I'll have a beer in your honor this evening. Carl