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Old 07-26-2010, 04:13 PM   #1
ger
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Default Flat spot

I'm getting a flat spot at 5k, picks up after a second or less and goes to redline anyone encountered this?

Basics are mk1 1.6 greddy, Bipes, vortec FMU, FMIC, O2 clamp, 265cc tan tops. Boost 6-7psi

Plugs long reach NGK's (not sure of the ref off hand, long reach versions of BKR7E-11).

Base timing 18 degrees, bipes set to pull 8 degrees 3-4k rev map.

Air temperature 68 degrees.

No obvious detonation.

Anyone.
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Old 07-26-2010, 04:20 PM   #2
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Are you positive you're not getting any knock? Base timing is 10 BTDC so even with the bipes you're not actually pulling timing at all compared to stock. At 6-7psi if you're not running an intercooler or have bad fuel I could see some knock happening. Also, check to make your plugs are gapped correctly, if not a bit less gap than normal.
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Old 07-26-2010, 04:26 PM   #3
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Fuel seems good, i have a FMIC (decent bar and plate with diy pipes)
I do not have a knock sensor but did bear that in mind and listened carefully, no obvious knock.

i brought the timing slowly up to this point careful to listen out, this has just started and its not any hotter than normal, i use 99 RON fuel same as 95 MON AFAIK.

I guess i should be in WOT at this point so I'm ruling out the O2 clamp

I'll pick up a set of BKR7E's tomorrow the std plug is gapped at 1mm instead of 1.1 not sure what this is in thou

Just looking for ideas to try one at a time.

Last edited by ger; 07-26-2010 at 04:37 PM.
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Old 07-26-2010, 05:26 PM   #4
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what are you running for an intake manifold?
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Old 07-26-2010, 06:25 PM   #5
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Considering he is running bandaids. most likely stock.
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Old 07-26-2010, 06:53 PM   #6
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stock intake manifold.
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Old 07-27-2010, 12:34 AM   #7
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make some det cans and you'll be sure to hear if your knocking.

I believe that you are knocking and that is why the flat spot. Knock won't always be audible to our unaided ear until there is significant damage. The timing on the Bipes seems to be too high and not enough timing retard once in boost. Try tuning the stock timing to 14* BTDC and making the Bipes pull a total of 8* and see if that clears it up.

The best advice is to pull more timing and see what happens also buy a wideband and be sure of your of the AFRs. With the Vortech you might be dumping in way too much fuel and drowning out the power. I know I was doing the same at one point.

Last edited by seraph; 07-27-2010 at 12:40 AM. Reason: NINJA EDIT
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Old 07-27-2010, 10:17 AM   #8
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Seems as though the problem was bad fuel and timing on the edge of detonation.

Ran the tank down and refilled at another garage and the problem seems to have gone.

But just to be on the safe side, i have reduced the base timing to 16, pulling 8 with the bipes, this should be fine with 99 RON (95 MON) and FMIC.

It seems logical to dump the vortec and get a variable Fuel Pressure Regulator and WBO2.

Had a read of the MSPNP thread, the piggy back version seems appealing, leaving the std ECU to control basic functions, any major drawbacks with these over the full MSPNP.

Budget is the thing, the miata is a second car for fun, with 5 mouths to feed and a big *** volvo to run it doesn't leave much in the kitty.
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