What is the difference in spool between these turbo compressors ? I have a CT43 67/79 0.81AR, and i want to upgrade the compressor only (as the turbine is big enough), what do you think it will be the differnce in spool ? right now it has 1.8@5200 (on dyno) ?
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I dont have any personal experience but since turbo lag is mainly dependent from shaft/turbine dimensions and turbine housing AR I think that 100-200 RPM for each step would be a safe estimate. That if you don't have compressor surge.Go Holset or Go RS4 -
That seems quite laggy but then you have a large turbine wheel. Too large in my opinion unless your drag / track racing?Comment
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In fact is not laggy at all, i used this setup only for dragracing, but i think that that the increase in compressor size will generate much more lag, i dont thing that 76mm compresor (gtx42xx) will have over 1bar @ 5500 rpm, that why i asked, some one with different turbo inducer on same setup will know better ?Comment
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If you not changing the turbine wheel then your talking maybe 200 rpm for the 72mm and 400 for the 74mm. It's probably less for the compturbo
Example http://www.s2forum.com/forum/showthr...t=43787&page=7
I mean that was a major change in turbine wheel and compressor and the spool difference is a lot less than you would expectComment
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If so, then a 74mm seems to be a quite good choice, seems that the compturbos are better spooling that garrette lines. Also it has some strange turbine ration, for example 79mm is 100 trim, or how do you say it 79mm inducer / 79 exducer turbine wheel.Comment
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67/79 - so the 79 would be the inducer of the turbine then? Has to be, I don't see a 67 coldside matching well to a 79 exducer hotside unless Comp has some new wheels or something? What is the hotside exducer (typically 6765 or 6767)?Comment
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Most turbos have a bigger turbine exducer than a compressor inducer.Go Holset or Go RS4Comment
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Sure, that statement is fine, but if you look at Comp's lineup, a gap that big doesn't exist anywhere.
examples:
6265, 6465, 6767 (same), 7076. Nothing like 6779, which is a big difference.Comment
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But like I said perhaps this is something new Comp has just developed?Comment
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Not all the turbos are on the website the 79 is a straight wheel
Kai mentioned it when I was buying mineComment
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Infact didn't that other forum member with imsa s2 paint job have the same turbo
Chipen something?Comment
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Yeah I'm aware of that as well, for example dad's turbo is no longer there (CT3-6465). Interesting nonetheless. I wish they would publish more info
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Lol blood out of a stone! Justin wouldnt give me any compressor maps for the billet range.
Someone said it was to do with precision maybe maybe notComment
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Now, real life info, same car, same fuel. (The smaller turbo with leaks on intake manifold) . Checked the intercooler pressure lose (quite small 0.1 bar or close ).
1. Turbo CT43 - 67 mm inducer 79/79 turbine - 0.81 AR
2. Turbo CT43 - 78 inducer (105 exducer) 79/79 turbine - 0.96 AR
See the graph below - same dynoComment
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