IM dyno comparo: VICS vs VTCS vs Flat-top (EUDM) - Miata Turbo Forum - Boost cars, acquire cats.

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Old 12-13-2011, 07:39 PM   #1
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Default IM dyno comparo: VICS vs VTCS vs Flat-top (EUDM)



VTCS mani was de-butterflied.
VICS mani switchover was 5400 RPM
Tested on 2.0L n/a stroker motor by FM.
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IM dyno comparo:  VICS vs VTCS vs Flat-top (EUDM)-3-ims.gif  

Last edited by JasonC SBB; 12-13-2011 at 10:17 PM.
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Old 12-13-2011, 07:40 PM   #2
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For a track car with a >= 7400 RPM redline, the Flat-top is the clear winner.

For anything else, pick your poison.
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Old 12-13-2011, 07:41 PM   #3
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(Sent from phone via capitalism)

Now add boost and do it again. Kthnxbye
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Old 12-13-2011, 08:01 PM   #4
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IM resonance effects are not affected by absolute pressure. So with boost, should be about the same.

Affected more with temperature. Higher temperatures and pulses and sound move slower. So with high IATs, maybe the resonance effects are moved to a lower RPM.
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Old 12-13-2011, 10:15 PM   #5
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vics was operational? 5200?
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Old 12-13-2011, 10:17 PM   #6
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Yes operational, at 5400 RPM. I find 5600 RPM the "correct" point when RPMs are slowly rising. If RPMs are rising rapidly a lower switch point is better.

Last edited by JasonC SBB; 12-14-2011 at 01:08 AM.
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Old 12-13-2011, 10:26 PM   #7
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180whp with a stroker for 10k? Isn't emilio making 170whp with the non North American motors, slight head work, rb header, and tune. I could replicate Emilio's motors for 3k or so...
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Old 12-14-2011, 01:54 AM   #8
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Wait, with boost would gains follow the same percentage gain? Or would you just get a lousy ten hp.
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Old 12-14-2011, 03:17 AM   #9
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% gain.
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Old 12-14-2011, 03:32 AM   #10
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Up to a certain flow point.
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Old 12-14-2011, 03:48 AM   #11
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Has the book been shut on the gutted vs. functional VICS under boost?
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Old 12-14-2011, 04:06 AM   #12
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No
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Old 12-14-2011, 09:46 AM   #13
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Quote:
Originally Posted by JasonC SBB View Post
IM resonance effects are not affected by absolute pressure. So with boost, should be about the same.

Affected more with temperature. Higher temperatures and pulses and sound move slower. So with high IATs, maybe the resonance effects are moved to a lower RPM.

I understand this, but I still want to see it
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Old 12-14-2011, 09:41 PM   #14
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Quote:
Originally Posted by Faeflora View Post
No
OK, so if I have a VICS manifold on a turbo track only car (~15psi), do I get more area under the curve with the VICS intact or gutted?
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Old 12-14-2011, 09:59 PM   #15
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Quote:
Originally Posted by mr_hyde View Post
OK, so if I have a VICS manifold on a turbo track only car (~15psi), do I get more area under the curve with the VICS intact or gutted?
Define 'gutted'. Do you want to just remove the butterflies, or also machine it out into one big plenum?

--Ian
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Old 12-14-2011, 10:09 PM   #16
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machine it out into one big plenum seems like it would make more sense...I've seen a post where it looks like ZX-tex did this, but no before/after dynos or anything.
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Old 12-14-2011, 10:41 PM   #17
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Gutted in this context means reaming out the entire Helmholtz chamber and everything else into a giant plenium. Just removing VICS butterflys would make the manifold worse IMO. VTCS is another story - removing those butterflys is a no brainer.
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Old 12-15-2011, 12:22 AM   #18
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Any idea what causes that dip at 3500rpm?

Jim
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Old 12-15-2011, 12:40 AM   #19
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Quote:
Originally Posted by aaronc7 View Post
machine it out into one big plenum seems like it would make more sense...I've seen a post where it looks like ZX-tex did this, but no before/after dynos or anything.
FM's tried this a couple times (including yesterday, according to the thread on miata.net) with a VICS manifold and seen no improvement. That was in an NA engine, not a turbo one, but it shouldn't matter.

--Ian
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Old 12-15-2011, 12:50 AM   #20
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WTT: One VICS and one VTCS for one squaretop...
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