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Old 10-12-2006, 04:19 PM   #1
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Default Just curious about my bogging...

Heres the setup again;

Gt28
Lovefab downpipe and exhaust
Begi mani
no intercooler yet/crossover pipe
Olderguy's o2 clamp (a must)
6psi / 6 degrees of base timing
(pictures at https://www.miataturbo.net/forums/showthread.php?t=4921 )

Old vortech 12 to 1 because I ran out of money. I will install a pierburg very soon and I plan on either going adjustable begi/bipes, emanage ultimate, or aem ems (if wife gets a great job). I just wanted to get the car running and carefully enjoy it before I put it away for the winter. The car has tons of power at about 5k and above. But in second gear, from boost (about 2.8k) to 5k, it just bogs really bad (no power). Once it is really warmed up, it isn't nearly as bad and seems to have power closer to about 3.8k. I am either running too rich or starving, but why is the car so powerful at high rpms and why does it get better as the car warms up?

Their hasn't been a hint of ping (cross my fingers) in this cold weather and I haven't done any high speed runs for obvious lack of fuel management issues. I also assume that any one of my three choices will fix this, but I really want to know what it is. Also, would it be safe for me to adjust the timing to 10 degrees and just not take it past 5k? (to see if it is timing related)
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Old 10-12-2006, 04:23 PM   #2
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I have to start asking the basics first. How new are the plug wires and plugs? Recent fuel filter? Have you verifed fuel pressure is rising?
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Old 10-12-2006, 04:27 PM   #3
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New colder plugs, wires have about 5k on them. I definitely need a fuel pressure gauge, but why would it run so strong at higher rpms? Fuel filter has 29k (but will be replaced with pierburg.)
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Old 10-12-2006, 04:32 PM   #4
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No wideband either? Pull the plugs.....what do they show?

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Old 10-12-2006, 04:38 PM   #5
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Might want to raise the voltage on the O2 clamp a little. If it is better when warmed up, it sounds like the ECU is seeing too lean a signal from the clamp and throwing in too much fuel until you hit open loop, where the O2 is no longer referenced
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Old 10-12-2006, 04:50 PM   #6
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Good call......This may be the first time a dummy air/fuel gauge would be handy.
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Old 10-12-2006, 05:55 PM   #7
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I vote too rich since it gets better at high rpm. Isn't that 12:1 fpr way too rich for a 6psi set up? I think my 6psi sc unit was 4:1 or 6:1. Or is it adjustable?
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Old 10-12-2006, 05:59 PM   #8
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what fuel pump?
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Old 10-12-2006, 06:48 PM   #9
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6 degs of timing isnt helping things.
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Old 10-12-2006, 07:06 PM   #10
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6 degrees does make it feel a little flat. Not to be a sales ***** but have you thought about water injection at all? It should let you bring that timing back to 10 or more.
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Old 10-13-2006, 02:09 AM   #11
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Good advice everyone. The plugs have been good, no little white specks and not covered in black. I have heard that 8 to 1 is really what I need, so it probably is too rich. So the timing can't really cause the total lack of power, right? Also, how many turns should I turn the o2 clamp?

I will also pull my afr meter from my civic and give it a shot. Yes, I also want a wideband. We just got slammed with snow, about 5 inches, and its October 13!! Hopefully it will melt tomorrow. I am really curious about how the pierburg effects everything, but it will likely make it even richer. I wish I had more time and $ so I won't keep thinking about it all winter.

The water injection sounds really cool, but I can't even consider it yet until I get everything functioning smoothly. When I finally start knowing what I am doing....
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Old 10-13-2006, 10:36 AM   #12
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Put a digital voltmeter from white to ground at the pressure switch. Don't try to adjust it by guessing. As you received it, it should have been around .32 volts.

Increase the voltage slightly and try it (maybe to .38 volts) at different levels. You don't want to go above Stoich, which is .47 volts.
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