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Old 09-08-2011, 12:19 AM   #1
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Default Increasing boost and injectors

I'm going to be installing a TDR crank overlay pulley soon, bumping me into the 550cc EV14's and 11-12psig range (up from 320cc and 9psig).

For megasquirt (9495MSPNP), I want to make sure I've covered all my bases. Am I missing anything before I get on the road tuning?

Rescaled for fuel:
Req_fuel
Injector opening time
Cranking pw
Accel enrichments

Rescaled for boost:
AFR target table
Fuel VE table
Timing VE table


..and backed up the current tune .
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Old 09-08-2011, 02:20 AM   #2
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which 550cc ev14s are the ones you plan to use?
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Old 09-08-2011, 02:21 AM   #3
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he's using the five-o ones
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Old 09-08-2011, 02:27 AM   #4
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looking for part numbers off them
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Old 09-08-2011, 02:29 AM   #5
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http://www.fiveomotorsport.com/product-search/?v=13974

The last injectors on the page

026IMP550X

Not sure about BOSCH part numbers, but they're custom from five-o

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looking for part numbers off them
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Old 09-08-2011, 11:31 PM   #6
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One of the first starts with the EV14 injectors.
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Old 09-09-2011, 12:28 AM   #7
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silicone hose collapse on itself, nice. Plan to fix that later?
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Old 09-09-2011, 12:36 AM   #8
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Nah. The only thing bad with that currently is that it surrounds the AIT sensor and has the potential to heat soak if I sit idling for long periods of time after a hard drive. I call it the 'variable throttled volume' upgrade. I just make sure the clamps are extra tight at the ends so that the sudden expansion doesn't blow them off. Maybe somewhere down the road I'll pick up aluminum wire and weld some tube.

I posted over at the other forum also. One thing I'll need to figure out is scaling the VE_Table to reasonable values. Copy & pasted:

To idle around a 14.5:1 AFR, I needed to add 5-10 to the VE table for every 0.1ms drop in injector opening time. For example, it idles perfectly fine at 0.6ms and VE of 95-100 or 1.2ms and VE of 65-70.

It felt like the AFR fluctuated the least at 0.7ms & VE of 95, so presumably this is the idle opening time to base my tune around?

If I keep the opening time at 0.7ms, do I need to change other settings to get the VE_Table lower (increase Req_Fuel perhaps)?
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Old 09-09-2011, 02:45 AM   #9
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I'd probably keep your opening time around .7 to .75 and see how your car likes it. I'm idling really smooth right now with my settings, but I'm trying to see if I can get it smoother.

Right now, I have my Y-axis in the VE table starting from 27 kpa going up to 230. The lower left corner is at 83 (night run with lights on with MAT at about 70 degrees F). Weird enough, in lower rpms and higher kpa, it actually reduces my fuel load to 68-69.

Really I don't think there is a set type of VE table. you just have to find your best opening time you're comfortable, and just let the VE table do it's thing in autotune. Reverent's recommendations helped me when I first got started with the EV14's, but even he said to set it and what it says in the VE table doesn't matter too much as long as your afrs are good.

don't lower the req_fuel
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Old 09-09-2011, 10:10 AM   #10
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One thing on my mind is this, coming from the PW calc in the megamanual.

PW = REQ_FUEL * VE * MAP * E + accel + Injector_open_time

Considering the Req_Fuel and Injector opening times are constant, and assuming the "VE*MAP*E+accel" function is a finite value greater than zero...then by lowering the Injector opening time, I'm merely leaving more of the pulsewidth float in the variable parameters.

A larger injector opening time may unintentionally set a top limit (for large injectors) for the range "VE*MAP*E+accel" can utilize without creating too rich a mixture from too long a pulsewidth.

This adds up to your statement that, whether the VE values are 60 or 100 etc., I am giving the "VE*MAP*E+accel" function more influence in the pulsewidth calculation, and the final pulsewidth will be sufficient.
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