When switching from 305 to 460cc injectors how much will I have to lower the VE table - Miata Turbo Forum - Boost cars, acquire cats.

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Old 05-11-2008, 11:14 PM   #1
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Default When switching from 305 to 460cc injectors how much will I have to lower the VE table

Ok so im throwing the 460ccs on, and I know to change the rq fuel, but then about how much / do I need to drop the points on the VE table by?

Like im saying does changeing the rqfuel chenge the ve table as a whole?
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Old 05-11-2008, 11:17 PM   #2
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No wideband? let me see if i can find the thread on this. I did it a couple of months ago.
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Old 05-11-2008, 11:19 PM   #3
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https://www.miataturbo.net/forum/sho...ighlight=460cc

It looks like 60 is a good place to start.
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Old 05-11-2008, 11:23 PM   #4
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You don't drop the VE table at all. You adjust the reqfuel, crankings PWs, and accel enrichment.
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Old 05-11-2008, 11:57 PM   #5
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I have a wideband, I just wanted to know to make life easyer. Thanks guys!
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Old 05-12-2008, 12:08 AM   #6
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It should start by changing the stuff that cjernigan said. FWIW my car idles really well at about 12:1 AFR so if you can get it close to that you should be good.
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Old 05-12-2008, 07:42 AM   #7
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Really, you ought to know what you're doing, not just following sheep (read: check out the megamanual, please). The fuel injected into your engine is mainly calculated from Req fuel and the VE table. So if you correct for the injector change via the req fuel...
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Old 05-12-2008, 11:33 AM   #8
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Quote:
Originally Posted by cjernigan View Post
You don't drop the VE table at all. You adjust the reqfuel, crankings PWs, and accel enrichment.
This needs to be pounded into peoples brains.

If you don't change the required fuel value then you would have to drop all your VE table values to the reciprocal of the percentage of increase.

305 to 460 is a 150% increase in flow. so you need to reduce your Required Fuel by the reciprocal of that, 1/150%(66%). That would take your 10.1 RF for the 305s to 6.7 for the 460s.

If you don't want to do that(for whatever reason) you can just go and change your whole VE Table. Highlight the whole thing and multiply by .66.

Now this isn't to say that your tune will be dead on still. There are other variables contributing to like the actual flow of each injector but you'd have to deal with that even if you swapped to the same size injectors.

I don't know why they didn't design the software so that it works this way for crankings PWs, WME and accel enrichments too.
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Old 05-13-2008, 02:18 PM   #9
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man... I'm going to be so lost when I start messing with MS..
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Old 05-13-2008, 02:57 PM   #10
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After you recalculate your reqfuel, you will have to tune the table some too. After I swapped my stock to 460 even after changing req fuel the values dropped about 5 points across the board.
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