Looking for 20g greddy twin turbos
05-18-2014, 08:06 PM
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Looking for 20g greddy twin turbos
Right now I have a twin turbo greddy 18g's however i would want to upgrade soon and have been looking online for pricing. Does anyone know where i can get 20g turbos for this greddy kit?
05-19-2014, 04:40 AM
#2
350Z-holic
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A subaru legacy GT buddy told me about BNR super cars out of Alabama (of all places) that does a bunch of turbo modifications. Might be a good place to start.
http://bnrsupercars.com/
I had my 18gs rebuilt by G-pop shop last year and I thought they did a good job - a local, non-dealership, volvo shop turned me on to them.
http://gpopshop.com/
http://bnrsupercars.com/
I had my 18gs rebuilt by G-pop shop last year and I thought they did a good job - a local, non-dealership, volvo shop turned me on to them.
http://gpopshop.com/
05-19-2014, 05:45 AM
#6
hatersgonnahate
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Well if you find them new please do post a link if it Is a vendor.
Most likely you will have a hard time finding bnib mitsubishi turbos.
I have tdo6h-20g chra stuffed in the 18g housing (modified) and will be getting tuned here soon.
Most likely you will have a hard time finding bnib mitsubishi turbos.
I have tdo6h-20g chra stuffed in the 18g housing (modified) and will be getting tuned here soon.
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06-05-2014, 09:26 AM
#9
FWIW, and it's a little known fact outside the DSM community, but MHI turbos are component balanced and do not require rebalancing when replacing components as long as no part of the rotating assembly has contacted the housing.
This means it's relatively easy to modify an MHI turbo with an aftermarket wheel and housing- just bolt it on and go. I've been modding MHI turbos this way for about 8 years, and I pushed mine pretty hard (30psi daily) without any failures. Honestly though, I would look at kawasaki turbo systems billet 18g wheel, since it will flow about the same as a 20g and spool quite a bit faster, and it would be a drop-in replacement. There are several variants with differing blade counts and heights. A tall 5+5 would spool similar to a standard 18g but outflow a standard 20g. A higher blade count would spool faster and flow a bit less. And you could use your existing compressor covers.
Higher flowing wheels like these require the upgraded thrust system though. You'll need the oiling plate with double holes and larger thrust bearing. Kamak sells them for like $20 each, and the comp wheels can be as little as $120 depending on which distributor you buy them through. There's no reason this has to cost more than $500 unless you're totally uncomfortable rebuilding a turbo- and you shouldn't be, it's not difficult.
20g wheels are garbage, IMO. They're an outdated diesel compressor that happened to find its way into performance applications. They surge pretty badly at higher boost levels (18psi+, less at altitude) because of the ridiculously high rotor ratio (and that same surge line exists to a lesser extent on the 18g wheel as well). The extended tip billet wheels are a significant improvement, as the tips decrease the rotor ratio (some people erroneously call this "trim") and the increase in blade exit angle reduces shock losses at high wheel speeds. No surge and about a 50% increase in flow, with a couple hundred rpm improvement in spool. There is absolutely no reason to continue using MHI cast wheels in these turbos.
This means it's relatively easy to modify an MHI turbo with an aftermarket wheel and housing- just bolt it on and go. I've been modding MHI turbos this way for about 8 years, and I pushed mine pretty hard (30psi daily) without any failures. Honestly though, I would look at kawasaki turbo systems billet 18g wheel, since it will flow about the same as a 20g and spool quite a bit faster, and it would be a drop-in replacement. There are several variants with differing blade counts and heights. A tall 5+5 would spool similar to a standard 18g but outflow a standard 20g. A higher blade count would spool faster and flow a bit less. And you could use your existing compressor covers.
Higher flowing wheels like these require the upgraded thrust system though. You'll need the oiling plate with double holes and larger thrust bearing. Kamak sells them for like $20 each, and the comp wheels can be as little as $120 depending on which distributor you buy them through. There's no reason this has to cost more than $500 unless you're totally uncomfortable rebuilding a turbo- and you shouldn't be, it's not difficult.
20g wheels are garbage, IMO. They're an outdated diesel compressor that happened to find its way into performance applications. They surge pretty badly at higher boost levels (18psi+, less at altitude) because of the ridiculously high rotor ratio (and that same surge line exists to a lesser extent on the 18g wheel as well). The extended tip billet wheels are a significant improvement, as the tips decrease the rotor ratio (some people erroneously call this "trim") and the increase in blade exit angle reduces shock losses at high wheel speeds. No surge and about a 50% increase in flow, with a couple hundred rpm improvement in spool. There is absolutely no reason to continue using MHI cast wheels in these turbos.
Last edited by kilogram; 06-05-2014 at 09:32 AM.
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iideadeyeii (08-28-2019)
08-28-2019, 05:57 AM
#12
Kilogram is right. The 20g’s suck. 18g turbos flow 41 lbs/min and 20g are only 44lbs/min. Forced Performance can modify your 18G turbos to flow up to 71 lbs/min including machining housings for about $700 each. I have been in contact with them recently for the same reasons as you. Really helpful and knowledgeable.
Old man- on a single pump, Charles at CJM recommended to me that i use a 370z fuel basket and modify it as outlined in his tech doc on his web page. He says they are much less restrictive and I got one used on eBay with 17k miles for $130 bucks. Looks like the most important thing would be shortening the rods to get the basket to fit the 350z tank which looks to be done easiest by using his 370z fuel module hat. Plus drilling the Venturi to maintain idle which you did to mod the 350z pump module for your dw300 (I’m running that pump too). Just a little bigger for the higher flow pump. I’m just gathering the parts to do this myself. Check out that tech doc.
http://host.cj-motorsports.com/pdf/3...ump%20Tech.pdf
Old man- on a single pump, Charles at CJM recommended to me that i use a 370z fuel basket and modify it as outlined in his tech doc on his web page. He says they are much less restrictive and I got one used on eBay with 17k miles for $130 bucks. Looks like the most important thing would be shortening the rods to get the basket to fit the 350z tank which looks to be done easiest by using his 370z fuel module hat. Plus drilling the Venturi to maintain idle which you did to mod the 350z pump module for your dw300 (I’m running that pump too). Just a little bigger for the higher flow pump. I’m just gathering the parts to do this myself. Check out that tech doc.
http://host.cj-motorsports.com/pdf/3...ump%20Tech.pdf
Last edited by hulkout; 08-28-2019 at 06:06 AM.
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OldManZ350 (09-23-2019)
08-28-2019, 06:52 AM
#13
350Z-holic
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OMZ - I ran a 485 for a few weeks, spun the bearing (October of 2018) and during my rebuild I dropped the 525lph in. I followed the 485 DIY that is floating around here. Other than a tight fit the 525 slides in like the 485lph.
09-23-2019, 11:19 AM
#14
Kilogram is right. The 20g’s suck. 18g turbos flow 41 lbs/min and 20g are only 44lbs/min. Forced Performance can modify your 18G turbos to flow up to 71 lbs/min including machining housings for about $700 each. I have been in contact with them recently for the same reasons as you. Really helpful and knowledgeable.
Old man- on a single pump, Charles at CJM recommended to me that i use a 370z fuel basket and modify it as outlined in his tech doc on his web page. He says they are much less restrictive and I got one used on eBay with 17k miles for $130 bucks. Looks like the most important thing would be shortening the rods to get the basket to fit the 350z tank which looks to be done easiest by using his 370z fuel module hat. Plus drilling the Venturi to maintain idle which you did to mod the 350z pump module for your dw300 (I’m running that pump too). Just a little bigger for the higher flow pump. I’m just gathering the parts to do this myself. Check out that tech doc.
http://host.cj-motorsports.com/pdf/3...ump%20Tech.pdf
Old man- on a single pump, Charles at CJM recommended to me that i use a 370z fuel basket and modify it as outlined in his tech doc on his web page. He says they are much less restrictive and I got one used on eBay with 17k miles for $130 bucks. Looks like the most important thing would be shortening the rods to get the basket to fit the 350z tank which looks to be done easiest by using his 370z fuel module hat. Plus drilling the Venturi to maintain idle which you did to mod the 350z pump module for your dw300 (I’m running that pump too). Just a little bigger for the higher flow pump. I’m just gathering the parts to do this myself. Check out that tech doc.
http://host.cj-motorsports.com/pdf/3...ump%20Tech.pdf
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OldManZ350 (09-23-2019)
09-23-2019, 11:52 AM
#15
Thanks so much for the Info........ 
Kilogram is right. The 20g’s suck. 18g turbos flow 41 lbs/min and 20g are only 44lbs/min. Forced Performance can modify your 18G turbos to flow up to 71 lbs/min including machining housings for about $700 each. I have been in contact with them recently for the same reasons as you. Really helpful and knowledgeable.
Old man- on a single pump, Charles at CJM recommended to me that i use a 370z fuel basket and modify it as outlined in his tech doc on his web page. He says they are much less restrictive and I got one used on eBay with 17k miles for $130 bucks. Looks like the most important thing would be shortening the rods to get the basket to fit the 350z tank which looks to be done easiest by using his 370z fuel module hat. Plus drilling the Venturi to maintain idle which you did to mod the 350z pump module for your dw300 (I’m running that pump too). Just a little bigger for the higher flow pump. I’m just gathering the parts to do this myself. Check out that tech doc.
http://host.cj-motorsports.com/pdf/3...ump%20Tech.pdf
Old man- on a single pump, Charles at CJM recommended to me that i use a 370z fuel basket and modify it as outlined in his tech doc on his web page. He says they are much less restrictive and I got one used on eBay with 17k miles for $130 bucks. Looks like the most important thing would be shortening the rods to get the basket to fit the 350z tank which looks to be done easiest by using his 370z fuel module hat. Plus drilling the Venturi to maintain idle which you did to mod the 350z pump module for your dw300 (I’m running that pump too). Just a little bigger for the higher flow pump. I’m just gathering the parts to do this myself. Check out that tech doc.
http://host.cj-motorsports.com/pdf/3...ump%20Tech.pdf
04-03-2021, 12:24 PM
#17
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