Originally Posted by Ben
(Post 465719)
I think we need to spend more time looking at builds like what Andy, CCC, and Eliminator are doing. They are showing us that using small turbos is a mistake.
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Originally Posted by Savington
(Post 466169)
They aren't showing us anything, Ben. 16psi at 4700rpm is fucking pathetic. Hustler is making the same power at the same boost, only his turbo spools over a thousand RPM sooner.
This is a comparison between your car and H-F's. They are roughly similar in execution, but you went with a 2871 and he went with an "oversized and laggy" 3076. Note he makes more power at every RPM. Attachment 203292 Attachment 203293 Who gives a fuck if it take a little longer to make equal MAP on a gauge, if you're making more power per PSI. Incidentally, Andy said he got 16 psi at 4300 rpm. On his stock computer, with a weaksause built engine. 330 cc injectors @ 120 psi and a bipes. Andy didn't have a nice NB head. His block was a 95 with forged pistons and stock GTX (or GTR dont remember) rods. No fancy machine work. Tell me that Jeff's motor wouldn't spin that turbo up 500 rpm sooner, if not more. |
Ben, have you ever actually driven a big turboed car on a track? My 2871R makes more power and torque than my 2554R did from 3000rpm up - it doesn't make the 2871R any less difficult to drive. The 2554R feels like an OEM turbo, plant your foot and go IMMEDIATELY, where the 2871R takes that little bit of time - even if it's only a second or so - to wind up and kick you in the rump. You can whine and brag about how your HUGE turbos make more power everywhere, but all I see from HF's chart is a torque curve that slopes up in a big way, which makes for a car that is peaky and nasty to drive - end of story. If we both snap the throttle open on a dyno, and you make more torque at an earlier RPM, that's great - but do you honestly believe that if we jump on the highway at 4000rpm and snap the throttles open at the same time, that 3076 is going to wind up and pull sooner than a 2860 or a 2871?
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Yeah ben if you look at the chart cuting it off at 4k rpm savs turbo makes more torque considerably more torque. Sure after 5k he is a sitting duck but outside of a drag strip the difference in torque makes the smaller turbo faster and just all around more effecient, for raod and general performance driving where you cant just go from one redline to the next progressivly up the gears. At 3k rpm the dif is like 40 lb/ft that is nothing to sneeze at.
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Originally Posted by Savington
(Post 466250)
.....do you honestly believe that if we jump on the highway at 4000rpm and snap the throttles open at the same time, that 3076 is going to wind up and pull sooner than a 2860 or a 2871?
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1 Attachment(s)
Originally Posted by Savington
(Post 466250)
Ben, have you ever actually driven a big turboed car on a track? My 2871R makes more power and torque than my 2554R did from 3000rpm up - it doesn't make the 2871R any less difficult to drive. The 2554R feels like an OEM turbo, plant your foot and go IMMEDIATELY, where the 2871R takes that little bit of time - even if it's only a second or so - to wind up and kick you in the rump. You can whine and brag about how your HUGE turbos make more power everywhere, but all I see from HF's chart is a torque curve that slopes up in a big way, which makes for a car that is peaky and nasty to drive - end of story. If we both snap the throttle open on a dyno, and you make more torque at an earlier RPM, that's great - but do you honestly believe that if we jump on the highway at 4000rpm and snap the throttles open at the same time, that 3076 is going to wind up and pull sooner than a 2860 or a 2871?
No, I think the 3076 is too big. But you didn't give any attention to Andy Floyd's 3271, which is a much better illustration. Remember Andy had a ghetto engine and no management. I think the most interesting data is in Andy Floyd's dyno and in the FM 2560 vs 3071 plot. Giving up avg 10 ftlb below 4k rpm to gain avg 75 ftlb everywhere over 4k seems like a good idea to me. Sav's Attachment 203291 Andy Floyd's 3271 https://www.miataturbo.net/forum/att...6129-16psi.jpg http://www.flyinmiata.com/uploaded/i...0vs%203071.jpg |
2871r on my car this past weekend.
OK, so i got the 2871R
Spools about the same. I have a very quick tune going though. basically nothing was changed but the af to make it safe for this past weekend's event. I am def down on power and tq. I finished 2nd Saturday so I get to go to the nationals. Anyway, tonight I will post the dyno with the 1 hour tune on it. i think I have some solid room for improvement with timing and maybe some more boost. I def think we can get it to spool a bit faster.. Once that happens I will post that too |
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