Gtx2860 gen2-- 373whp/351tq-- 22psi
#42
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I absolutely agree. The 67 has a lot more headroom at higher PR. There is a guy with a YouTube channel and a 4age and he did a back to back on the 2860 and 2867 gen 2. 300rpm spool difference which on the street you probably hardly feel
#43
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The real reason I got the Gen2 2869R is because
My Gen 2 GTX2860R showed up yesterday. I also heard that my G25-550 finally shipped. That should get to me next Tuesday. Hopefully I get some dyno time scheduled soon.
#44
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as there is some conversation about this, and it is something I have really looked at in detail, I figure I will post a couple of things I find interesting.
There is a really small space where the GTX2867R G2 will out-spool the 2860 as well as out flow it. For modern turbos on small displacement engines, you ride the surge curve until you hit your PR target. It is really evident in the logged PRs from my setup. I think Garrett must have had an OEM request to revamp the compressor characteristics, as the Gen 1 compressor was more efficient over most of the map. When they came out with the G2, the biggest change was in this surge bump. I have run both the G1 and the G2, and sure enough the G2 has the bump profile on the PR curve vs RPM in the real-world data. Pretty fascinating.
The first image here shows the bump when you overlay the maps, The second shows the "Bump" from the surge line in the real data. Once the turbo PR hits ~2.25 - 2.5 it immediately jumps to 3. The second also shows a scenario where a GTX2860R would be superior to a GTX2867R G2 with a PR of 2 in terms of spool.
edit: 3rd gear pulls, 6 speed
There is a really small space where the GTX2867R G2 will out-spool the 2860 as well as out flow it. For modern turbos on small displacement engines, you ride the surge curve until you hit your PR target. It is really evident in the logged PRs from my setup. I think Garrett must have had an OEM request to revamp the compressor characteristics, as the Gen 1 compressor was more efficient over most of the map. When they came out with the G2, the biggest change was in this surge bump. I have run both the G1 and the G2, and sure enough the G2 has the bump profile on the PR curve vs RPM in the real-world data. Pretty fascinating.
The first image here shows the bump when you overlay the maps, The second shows the "Bump" from the surge line in the real data. Once the turbo PR hits ~2.25 - 2.5 it immediately jumps to 3. The second also shows a scenario where a GTX2860R would be superior to a GTX2867R G2 with a PR of 2 in terms of spool.
edit: 3rd gear pulls, 6 speed
#45
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Ted,
I love it when you talk nerdy to me!!! I have thought the EXACT same thing as you have. Garrett Gen1 was more efficient but the surge line was much worse therefore the spoolup was slower, with the Gen2 the compressors have a much more upright surge line which helps spool a LOT. My 2860 literally spools like a 2560 which is quite an achievement. As you have shown the 2860 will outspool a 2867 until you get into that bump on the surge line which is SUPER interesting. I need a 2867R so bad lol, the 2867 has about 40hp more headroom it looks like vs the 2860. I have seen people make right over 400whp on a gtx2860 Gen2 and it was probably riding the outer surge line to get there.
I LOVE your post man I enjoy this tech talk there isnt enough of it.
I love it when you talk nerdy to me!!! I have thought the EXACT same thing as you have. Garrett Gen1 was more efficient but the surge line was much worse therefore the spoolup was slower, with the Gen2 the compressors have a much more upright surge line which helps spool a LOT. My 2860 literally spools like a 2560 which is quite an achievement. As you have shown the 2860 will outspool a 2867 until you get into that bump on the surge line which is SUPER interesting. I need a 2867R so bad lol, the 2867 has about 40hp more headroom it looks like vs the 2860. I have seen people make right over 400whp on a gtx2860 Gen2 and it was probably riding the outer surge line to get there.
I LOVE your post man I enjoy this tech talk there isnt enough of it.
#46
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I'm just curious now, so I'm gonna ask here since you guys seem to know what you are talking about.
I have a oldskool gt2860rs turbo, can this housing be used along with a newer gen CHRA as an upgrade?
I have a oldskool gt2860rs turbo, can this housing be used along with a newer gen CHRA as an upgrade?
#49
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Most Recent virtual dyno pull I have. This was right after I installed my built head ( see my build page for more info on that....
This is the first time I have seen my car make 400whp on any VD pull I have done. Tq is slightly inflated because I actually spun 5th gear slightly on this pull, 40* temps outside and 200tw tires turn into plastic big wheel tires.
Most recent VD pull I have on the built head I just installed.
This is the first time I have seen my car make 400whp on any VD pull I have done. Tq is slightly inflated because I actually spun 5th gear slightly on this pull, 40* temps outside and 200tw tires turn into plastic big wheel tires.
Most recent VD pull I have on the built head I just installed.
#51
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I have my 93 octane map and my 100octane map in there.
https://www.miataturbo.net/build-thr...burning-96993/
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