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Turbo choices Holset HX55?

5K views 11 replies 5 participants last post by  A sad fat dragon  
#1 ·
Ok I went back to the drawing board selling off the small S360 I was using for mockup and have my eye on a pair of Holset HX55's which are pretty close to BorgWarner EFR 9180s as I can get them cheap here

So if I was to say its either going to be a 502 at 9.19:1 CR or a 521 at 8.91:1 CR really fuck all in it price wise, about $50 I think

The spec on the Holsets is

99mm billet MFS 7 blade deep superback compressor wheel with 67mm inducer
86mm high flow 12 blade turbine wheel with 77mm exducer
.89a/r twin scroll T6 housing

Now from BW's matchbot site it seems like I could probably run that, their spec is a little different on the compressor size with a 92mm wheel and 68mm inducer but the turbine specs are pretty much the same with an 87mm .9 a/r

I know its not exact but it gives me the closest match up I can find

So with the goal of running 10psi maybe up to 15psi max (and this will all be broken in and tuned on a dyno not by me, I'm only amassing the parts!) to run on 99octane with booster if needed are these feasible?


The maps play out like this for the 521, close to the choke line at the max I'd ever take the engine to rpm wise but safe. Both 521 and 502 were within it when at 10psi or 15psi max


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#3 · (Edited)
Great turbos for the money, and a big turbine wheel, which is what you need for your capacity.

The turbine housings should be really fast spool on either of your capacities, but larger housings are very common for 55s so wouldn't be hard or expensive to go larger if you ever felt the need.

I know of a vehicle showing almost 650bhp at 12psi with half your potential capacity and 1x cast wheel HX55 with a larger turbine housing. And 4.2 Audi with a touch over 1000bhp at ~35psi with one too. They certainly won't struggle to make power.
 
#6 ·
Thanks, that's what I was hoping for! Plus with the billet wheels in this it's a little added extra, was wanting quick spool so I could Street drive it and not have masses of lag

It would be much easier if Holset would give us a calculator like Borg do!

I've put in a bid on a pair anyway, had the choice between this pair and another with water cooling too but decided not to go with them. Slightly smaller wheels too....only 1mm but the exhaust housing was 22cm which I thought would be a bit slow to build the boost up