I'm having the hardest time finding this. I need as much info as possible about cutting an mwe slot in an h1c turbo. What tool to use, how deep, what angle, etc... Or if i should just bring the housing to a shop to do it? Thanks

 

It's actually not a single answer. Turbo manufacturers will "tune" the surge line by varying placement and width of the slot. There is a tradeoff in efficiency (~0.5 point loss typical) that comes along with it. I don't have direct data to suppot this but would expect that the further downstream the groove is the bigger the benifit to the surge line the bigger the detrement to efficiency.

The groove is typically anywhere from just upstream of the splitter blades to somewere halfway between the inducer and the splitters. For grove width I would say plan in the range of 1-1.5mm wide. These are just estimates based off of typical turbos I've worked with. There are some grooves that are angled but that's difficult to machine so stick to a radial groove.

Are you actually encountering surge during spool-up or steady state operation (not during decels or throttle closure)? If you aren't then don't bother as you'll just be hurting performance.

Steve

 

Do you happen to have a picture of a where its normally located? Btw its on a 12v cummins diesel. I want it for two reasons: first is because i'm going to be towing a boat 4 hours at a time and some areas are stop and go and i want to remove any possibility of damage and i've read that this can help. And also, of course, the sound is awesome

 

Sorry. I don't have any pictures. If you're running the stock non-wastegated turbine housing on that H1C you won't be anywhere close to putting the compessor into surge. This modification will have zero performance or durability benifit. It will actually make performance a bit worse as the air coming out will be slightly and lower pressure (but only by a very slight amount).

I won't argue with the sound benifit though as it will make the turbo whistle louder.

Steve

 

I guess i will take it to a shop because it seems like it might be out of my league with the tools i have available to me.

 

Your H1C has a ported housing without the groove cut?

 

Firstly, does it have enough material to machine into?
The depth is , to the secondary blade height.
I use a modified 1/8th part off tool in the lathe.
Either use a indexing head and drill down to that slot...using multiple holes,
Or use a mill end bit and machine a radius , leaving blocks every 1/4 turn to hold the piece in the comp housing.
Yes u lose comp wheel eff. As it disrupts air flow in,
But u gain shaft speed recovery on surge, throttle closing, spool up etc

 

I read that a few times and don't get it, how do you use a parting tool in a lathe and leave material every 1/4 turn?

 

Not on parting tool...
From the front,
not level with secondary blades

 

What kind of H1C housing is in question?

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If it's the ported housing on the left, then it's just a matter of cutting a slot in the right place and all the way through into the open space of the ported area. This eight-bladed HX40 I had was equipped with a slot right above the lower blades.

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Here you can see where it was cut all the way through.

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