injector size too large?

sc91183 · Post by **sc91183** » Fri Sep 08, 2006 12:10 pm

I am running a Porsche 3.0 liter with 46MM ITB throttle bodies,stock cams and compression and 30 lb. per hour injectors. I can get the car to run good but not great it just seems to be a little off. When I purchased this EFI "kit" the seller was going to supply 20 lb. per hour injectors but couldn't get them so they sent 30's instead. Do you guys think 30's are too large? I'm down to 1 squirt per cycle and it still seems rich. I have a wideband O2 that constantly reads around 10.5 to 1 regardless of VE settings. My MSII is 3.0 with 2.25 software. Help!

sc91183 · Post by **sc91183** » Fri Sep 08, 2006 12:10 pm

I am running a Porsche 3.0 liter with 46MM ITB throttle bodies,stock cams and compression and 30 lb. per hour injectors. I can get the car to run good but not great it just seems to be a little off. When I purchased this EFI "kit" the seller was going to supply 20 lb. per hour injectors but couldn't get them so they sent 30's instead. Do you guys think 30's are too large? I'm down to 1 squirt per cycle and it still seems rich. I have a wideband O2 that constantly reads around 10.5 to 1 regardless of VE settings. My MSII is 3.0 with 2.25 software. Help!

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FoundSoul · Post by **FoundSoul** » Fri Sep 08, 2006 12:27 pm

That's a 6cyl right? Turbo?

On a turbo 6cy those injectors should be good for about 250 crank hp. For a NA 6cyl that should be good for closer to 300 crank hp.

Either way I'd think you could get these to run just fine, you might try two squirts alternating and see if that helps. Are the low impedance or high?

FoundSoul · Post by **FoundSoul** » Fri Sep 08, 2006 12:27 pm

That's a 6cyl right? Turbo? On a turbo 6cy those injectors should be good for about 250 crank hp. For a NA 6cyl that should be good for closer to 300 crank hp. Either way I'd think you could get these to run just fine, you might try two squirts alternating and see if that helps. Are the low impedance or high?
Jerry a.k.a. 'FoundSoul' 86 MR2 NA w/MSnS-E Available: MapDaddy - 4-BAR MAP Sensors w/ Baro Correction

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PSIG · Post by **PSIG** » Fri Sep 08, 2006 1:02 pm

sc91183 wrote:...I'm down to 1 squirt per cycle and it still seems rich...

As Jerry says, 30's should be fine. Note that the number of squirts is not directly related to tuning your idle richness. That is usually accomplished by reducing the VE number in the area (bins) you are idling to the lowest average MAP value. You may want to review the tuning section in this chapter: http://www.megamanual.com/v22manual/mtune.htm

David

PSIG · Post by **PSIG** » Fri Sep 08, 2006 1:03 pm

sc91183 wrote: ...I'm down to 1 squirt per cycle and it still seems rich... As Jerry says, 30's should be fine. Note that the number of squirts is not directly related to tuning your idle richness. That is usually accomplished by reducing the VE number in the area (bins) you are idling to the lowest average MAP value. You may want to review the tuning section in this chapter: http://www.megamanual.com/v22manual/mtune.htm

David

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sc91183 · Post by **sc91183** » Fri Sep 08, 2006 4:12 pm

It is a normally aspirated engine. I thought going to 1 squirt per cycle would mean less fuel? I have adjusted the VE table to lean ( poor throttle response ) and then slowly richened until good response. I have minimal AE and I'm running in Alpha mode vs. speed density. I'm also running 100% TPS. I just can't seem to get it perfect or at least close to perfect. And no matter how I calibrate the O2 sensor I can't get the Megatune AFR to stray much from 10.5 to 1. I don't think I'm running that rich but it is rich. My biggest struggle has been getting a consistant idle, when I adjust the idle stops on the throttle bodies to a consistant 900 rpm sometimes it will return to 900 after a drive,sometimes it will drop to 500-600 and sometimes it will go to 1100 or so. I have adjusted the throttle linkage,added return springs,greased all pivot points and of course have adjusted MS forever.

sc91183 · Post by **sc91183** » Fri Sep 08, 2006 4:12 pm

It is a normally aspirated engine. I thought going to 1 squirt per cycle would mean less fuel? I have adjusted the VE table to lean ( poor throttle response ) and then slowly richened until good response. I have minimal AE and I'm running in Alpha mode vs. speed density. I'm also running 100% TPS. I just can't seem to get it perfect or at least close to perfect. And no matter how I calibrate the O2 sensor I can't get the Megatune AFR to stray much from 10.5 to 1. I don't think I'm running that rich but it is rich. My biggest struggle has been getting a consistant idle, when I adjust the idle stops on the throttle bodies to a consistant 900 rpm sometimes it will return to 900 after a drive,sometimes it will drop to 500-600 and sometimes it will go to 1100 or so. I have adjusted the throttle linkage,added return springs,greased all pivot points and of course have adjusted MS forever.

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sc91183 · Post by **sc91183** » Fri Sep 08, 2006 4:16 pm

Yes it's a 6 cylinder and they are high impedance injectors. I will try the 2 squirts alternating and see what that does. Thanks for the suggestions.

sc91183 · Post by **sc91183** » Fri Sep 08, 2006 4:16 pm

Yes it's a 6 cylinder and they are high impedance injectors. I will try the 2 squirts alternating and see what that does. Thanks for the suggestions.

Posted by email.

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