VVT + VICS + Boost + MS3X = ??
#61
Overbore has been calculated into specific torque output already. Still at ~75. Exhaust may be better but I'm at 5 psi backpressure and a 3 psi reduction won't get you from 68 to 75, especially since I'm operating the GT2560 closer to its max efficiency island (200 kPa, vs. 230). I have headwork too, and oversized valves. Note that my buddy Ian got almost exactly the same torque curve as me, even tho I have VVT and a shorty tubey manifold, and he doesn't.
#63
When I try to sell the turbo, I get smart guys saying it is run of the mill turbo which is valued at $100-200 in great condition. When I dyno or race it I get different smart guys telling it cannot produce the results it does.
Piping has effect and this one could not fit into Miata as Ben told, unless you move front suspension 2' forward and firewall 1' back.
Turbo is still for sale so I can get that EFR or GTX there like designed. I want to have throttle steer on fifth gear as well
#64
I agree that piping is more critical than ppl realize
why I have fins on the twin charge pipe between the turbo and the dual inlet intercooler
larger volume, lower velocity, longer residence in heat rejection area BEFORE I/C
grab as much charge cooling as possible without sacrificing flow
sorry I missed the hill climb, would have loved to have seen your car perform, sure looks nice on facebook
instead I got to do solo laps at Bristol
but planning to be there for the next event
why I have fins on the twin charge pipe between the turbo and the dual inlet intercooler
larger volume, lower velocity, longer residence in heat rejection area BEFORE I/C
grab as much charge cooling as possible without sacrificing flow
sorry I missed the hill climb, would have loved to have seen your car perform, sure looks nice on facebook
instead I got to do solo laps at Bristol
but planning to be there for the next event
#66
Fancy head work and a really efficient exhaust with a 2560 ought to make more power up top, but also let the turbo spool up at an even lower RPM. That's why I don't understand why hrk's dyno chart doesn't show 200 kpa until 3700 RPM, while my car (2560 with vanilla FM2 parts) does it at 3300. I would have expected to see it around 3100 RPM on hrk's plot.
This is why I asked if the '2560' had been a typo for '2860'. It's not though, the part #s off the compressor and pictures do indeed point to a 2560.
Are there any boost leaks that would be delaying spoolup?
--Ian
#69
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I think it has more to do with the dyno not presenting enough load at the beginning of the pull. It releases the axle and allows the engine to rev up at a fixed rate, set up as a user configurable option in delta RPM / second. I have noticed that turbo car tend to spool faster with their wheels on the ground compared to the dyno. Heikki may have a log saved from last weekend that we could use to compare spool on the track vs spool on the dyno.
#70
I think it has more to do with the dyno not presenting enough load at the beginning of the pull. It releases the axle and allows the engine to rev up at a fixed rate, set up as a user configurable option in delta RPM / second. I have noticed that turbo car tend to spool faster with their wheels on the ground compared to the dyno.
#71
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Holding the car back for a few seconds is very hard on the car, quickly creating very high temps. Part of tuning is keeping conditions stable so you can correctly value the effectiveness of the changes made between pulls. Another part of tuning is not putting the engine in danger, IE lugging the engine at massive load for an extended time.
I think a better option would be if a knee point were added in software, allowing to change the slope of the pull rate at after a configurable RPM.
#75
That would be nice to know. The shop I had the miata at, knew exactly what to run for an s2000 or a stock miata but I kind of just pulled a number out of my *** for my car because they had no idea.
Last edited by Leafy; 06-26-2013 at 09:54 PM.