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Anyone know?

prove_it

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Anyone know what machining is needed to convert a 14b center section to fit the 20G wheel? Yea, I know a bastard question, but been digging for info on the exact machining that needs to be done. Not looking for a how to, nor the compressor cover machining. I got a guy willing to machine the housing for me, but he's clueless on what to machine and how much.
 

AllanL

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measure the outer diameter of the 14B comp wheel.

measure the outer diameter of the 20G comp wheel.

the depth of the step where the comp wheel sits are the same, just the outer diameter of the wheels are different, and thus needs to be made bigger going from 14B to 20G.

14B is approx 58mm [2.285"], so the center section is approx 59mm.

20G is approx 68 [2.2680"], so center section is approx 69mm.

he'd have to bore the step where the comp wheel sits by 10mm.

hth
 

prove_it

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Thanks, I was wondering if that's all it was. Wasn't sure if the superback design needed to have anything special.
 

fuel

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I was under the impression the super back recess was deeper - or more so sloped but unsure how much by.
 

Wizardawd

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The plate behind the 14b wheel is flat, whereas the 16g+ back plate is concave. You should be able to swap in a 16g back plate and then machine the compressor housing to fit the 20g wheel. They actually sell the 16g-20g conversion on ebay and it consists of only a wheel and machined housing.

Wiz
 

AllanL

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Quoting prove_it:
Thanks, I was wondering if that's all it was. Wasn't sure if the superback design needed to have anything special.



the flat back/super back wheel difference basically does not have any relation to the housing bore.

the back plate is what 'decides' it for the wheel back shape.

converted 14B --> 16G --> 20G twice already...

hth
 

prove_it

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So really all I need to do is have the center section machined a lil bigger to accept the new wheel then? No tapering or anything special? Just make the circle bigger?
 

AllanL

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Correct.

Your machinist will know what to do if you show him both 14B and 20G wheels and the center housing WITHOUT the back plate...

center bore step dia = wheel/esducer diam + 1~1.5 should be just right.

But he can verify the step bore using the 14B installed on the center housing...
 
Last edited:

tektic

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Yeah the taper is only in the center piece that comes with the rebuild kit.

Just increase the diameter of the step to make the wheel fit. Machine the thrust surface to accommodate the 18mm spacer and then the cover. That's a little more difficult but the same idea.
 

Wizardawd

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Quoting AllanL:
Quoting prove_it:
Thanks, I was wondering if that's all it was. Wasn't sure if the superback design needed to have anything special.



the flat back/super back wheel difference basically does not have any relation to the housing bore.

the back plate is what 'decides' it for the wheel back shape.

converted 14B --> 16G --> 20G twice already...

hth



But you can't just slap a 16g/20g wheel and matching housing onto a 14b center cartridge. You have to change the backing plate (the one directly under the compressor wheel) to the G style for anything 16g+. That was my point.

Wiz
 

tektic

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I don't think anyone disagreed. In fact I concurred.

Purchase list
-superback rebuild kit
-20g wheel

Machine
-compressor cover
-cartrage step diameter
-thrust spacer diamater

Or obviously you could just buy a new cover as well.
 

prove_it

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Already got a 20G machined comp housing in a box of parts. That's why I'm looking at just getting parts, having a local machine do the center housing, and assemble it myself. Now that it's not a daily, I'm not too worried if it fails and the car is down for a week.
 

tektic

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I still haven't heard anything from turbo lab about my rebuild kit. They did make me a cover for I want to say $35 last time I asked. If you do get it from them ask them to open up the inlet as much as possible. They didn't touch mine only the impeller profile. They have a decent price on the rebuild kit and wheel too. I hope the send you the right parts the first time though.
 

prove_it

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loL. Not sure who I'm going to source parts from. 14of2000 (Mike) had a bastard built by them, no issues on his, also the new owner of it said it's working great, so long term is looking good.

I'm more concerned with a cheap wheel as I'll be pushing it hard. Dunno, trial and error I suppose.
 

prove_it

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Cause I have a good turbine wheel, mitsu center section, and a machined cover laying around. Hmmmm 150 in parts, or 800 for a new turbo.......

If I had the funds, (ie not needing to repair a blown trans) I would go with a 68hta with the flow enhancement cover.

Also, I auto-x this thing so I really like the spool of a TD05h turbine wheel, but looking for more high end my s16g has. A b16G would be dumb as there isn't much gain from the S16G, so....

Why not hack up one of my several blown 14Bs into a bastard with a modded 16G cover for downfiring for less than 150 bucks?
 

GSTwithPSI

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Turbo lab has an online store (on Ebay click ) I was looking through the other day. They have a bunch of billet 20g compressor wheel options. The thing is, I'm not sure what the quality on these things is. If you look around on Ebay, you see what appear to be the same wheels offered up out of Japan and China from other sellers, which I would take to be a bad sign. But, maybe not? I'm kinda just making the Ebay assumption here, and could very well be wrong. I looked around on T00ners, and Turbo Lab of America didn't seem to have a great rep over there. I have a few shitty 14b's laying around myself I wouldn't mind playing around with. Let us know what parts you decide to go with, Ryan.
 

tektic

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Like I said before what I read in multiple places was that tdo5 can't push a 20g hard enough to make a difference between the billit and the narrow shaft cast impellers. The builit wheels cost 2-3 times what the cast ones do. Also take weight I to consideration before you decide. The cast wheels are usually lighter. If you can find flow charts post em.
 

GSTwithPSI

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Anyone know where you can get a stock appearing compressor cover that'll fit the 20g compressor wheel?

Alternatively, what are guys running the down firing 20g compressor covers doing for the WG actuator?
 
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