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Stock Twins King
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So I am providing what I hope is the last update. Manifold is now in production with an ETA first of January or so. I was waiting for a fellow GT28 owner to do final back to back dyno comparisons over his log manifold. He was very meticulous on providing step by step installation, noting issues in every way. Some were VERY helpful. We then changed the drawings from his observations. One area had an unforeseen thin wall area that we corrected. Ken's Supra is near stock. He runs on race gas for dyno's and drag racing. This run was with race gas and I think about 28psi on a stock motor. He is an AUTO which will make his power lower than a 6sp. For the past 5 years, he is constantly running in the mid 10's at a peak HP around 590whp with drag radials. This spring hopefully he will hit the strip and get lower ETAs.

However, his dyno wasn't as expected. Not that there were some gains, but he had issues with his car. Either plugs, VSVs, or some other ignition breakup that resulted in a wacky curve up top. He thinks it might be is Auto tranny slipping or something. So he is resolving these issues and will re-dyno hopefully soon. But this is not stopping me to pour them. Hopefully he will have a new dyno about the time the manifolds are done.

So here is his weird dyno. The good of it is he has gained 40whp low and above but between 5000-7000 his car has issues. So for now, I am going to assume that his curve will get cleaned up and he will show +40whp across the board. Blue is new, Green is old. Overall the Dyno shows almost '0' gains at the peak(s). Bottom line is not taking this graph as gospel for gains.

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Stock Twins King
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4,415 Posts
Great news Stu, I'll definitely be buying one. Just wondering is this a comparison between a stock manifold or the previous stainless upgraded manifold.
Read my 3rd line....dyno comparisons over his log manifold
 

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thanks for the update stu. ive been following this for years and i think the manifold is what will finally trigger the begining of my build.
just one question, who is making the latest revision of the turbos with all of the upgrades (V3 and WG) and do you think there will be any future updates (gtx28...)?
 

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Having lightly kicked around this option over the past couple years, and my turbos now giving me the death whine, I’ve finally found this thread with all this awesome data. I have a 93 non VVTI JDM RZ, and I’m really trying to figure out the best way to execute my repair/upgrade. It’s awesome to see I may be jumping in right as the manifold is completed!
 

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Does this manifold etc. match up cleanly with the Suprastore upgraded turbos ? I would imagine it would for upgraded usdm ones - how about the jdm ones ?
 

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Given that suprastore will buy jdm turbos for you for $650, while the upgrade for usdm ones is way more $$, how much of a downside are the jdm ones ? I'm toying with the idea of getting Stu's manifold and a set of upgraded jdm turbos if that's worth it compared to the usdm ones.
 

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Stock Twins King
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In regards to fitment of this manifold, it is designed to fit JDM or USDM perfectly. This is the main reason for all the time and R&D I have put into this. It has been tested a ton of times. Only issue is there might be s light off set matching the turbo collector to down pipe, You will have issues if you install GT28's on a JDM Supra only because the JDM down pipe has a different bolt patter. If installing the manifold to JDM turbo's and a JDM car then no issues.

FWIW I am running now a set of JDM (Mitsubishi 16G cartridge) style upgraded turbos, and manifold in my USDM Supra. I had to cut off the USDM DP flange and install a JDM flange so my down pipe would match up. There isn't really all that much difference on the JDM upgrades, power wise. I made 620whp with the JDM upgrades, and 680whp on the GT28 USDM upgrades. Nice thing on the JDM upgrades is they are plug and play, no oil or water lines required. This is a $500 savings over the GT28's. BNR sells these for $1750 on his website. Would require your cores in exchange.
 

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Stock Twins King
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so stu, i believe i read somewere that you were able to make just over 800 with all of your tweaks, was that on the USDM gt28's? how are the 16g's in comparison?
I would not take this as gospel but this was a DynoPac Hubcentric graph I did few years back. On the GT28s. 811TQ 775HP

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Stock Twins King
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stu, how you thought about reaching out to Munro and other companies in Aus, NZ and Europe. i'm sure they would take dozens of your manifold if you wanted to sell more.
I have sent emails to ARTEC with no response. I havent sent anything to Munro because I am the only person who has installed these in JDM version. I assume over time, someone will bring these to their attention to look at. There is a guy known in AU that ports JDM manifolds for like $300 that has shown pretty good gains.
 

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Stock Twins King
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4,415 Posts
stu, you sell the turbos?
I have been selling them for years.....Since I was the one many many years ago to hand sales over to SFS as I really couldn't sell on the forums. But I continued selling on the side. I do not promote I do sell them. I buy direct from BNR and ship direct.

FWIW, Bryan at BNR does sell directly to anyone....Just might be a few hundred more.
 
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