Hesitation around 6krpm on track - Page 3 - Miata Turbo Forum - Boost cars, acquire cats.

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Old 09-27-2010, 05:33 PM   #41
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yeah, that's in the ASE taper table
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Old 10-08-2010, 03:53 PM   #42
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Ok, we're back to square one.
- still lack of power at 6krpm
- new 0.025 extended reach plugs
- COPs with 3ms dwell
- No smoke from tail pipe, not when on power, not on overrun
- Dip stick comes out a little when ran hard

If it were rings, wouldnt the car smoke?
Could it be MSPNP related? I have no weird corrections anymore during boost. Something about pull up resistor or IGN driver circuit? It's a MSPNP9495 from DIY with spark output inversed and Trackspeedengineering COPs.

What could blow the dip stick out ofther than rings? New PVC valce in place. Something in the head? A crack, worn lifters?

Clogged CAT?

WHAT ELSE?#[email protected]!#$%
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Old 10-08-2010, 03:58 PM   #43
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Clogged air filter?
Dying CAS?
Clogged fuel filter?

Last edited by Laur3ns; 10-08-2010 at 04:53 PM.
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Old 10-19-2010, 05:49 PM   #44
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has this problem been resolved yet?
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Old 10-19-2010, 06:03 PM   #45
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My problem at 6k on the dyno appears to have been the momentary slipping of the clutch, and then it grabbing again. The issue became obvious this weekend at the track. I thought the clutch was appropriately rated, but then someone pointed out that the clutch tq is rated at the flywheel and not wheels. oops

I think I was just barely exceeding the rating, but at the track I repeatedly exceeded the limit, which most likely led to glazing of the clutch and flywheel.
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Old 10-19-2010, 06:08 PM   #46
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Mine: NEIN
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Old 04-18-2011, 06:59 PM   #47
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Still haunting this:

Quote:
Originally Posted by Spookyfish View Post
Ok, we're back to square one.
- still lack of power at 6krpm
- new 0.025 extended reach plugs
- COPs with 3ms dwell
- No smoke from tail pipe, not when on power, not on overrun
Someone help me gather info on this:

Could it be MSPNP related? I have no weird corrections anymore during boost. Something about pull up resistor or IGN driver circuit? It's a MSPNP9495 from DIY with spark output inversed and Trackspeedengineering COPs.

Or I may have to rip the MSPNP out and replace it with something else.
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Old 04-18-2011, 07:01 PM   #48
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The dip stick will be blow by related and I will plum a VC/crankcase ventilation system.

Maybe the 6krpm flat spot is from the blow by itself? Causing spark blowout or det?
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Old 04-18-2011, 07:02 PM   #49
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Another note: the 6krpm flat spot has been seen on a dyno - so not related to cornering.
It is also heat related: I can do one 2 minute lap on the track and THEN it will develop the issue.
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Old 04-18-2011, 08:13 PM   #50
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What do your plugs look like? If they are overheating (perfectly white with little black spots) then they may be getting hot enough to ignite your mixture spontaneously -- classic pre-ignition. Like detonation, but even worse. I've had it before, and it feels like the engine is missing violently. Let off the gas, and things smooth out. Back on the gas and after a brief period -- missing again. Spark plug appearance is a dead giveaway if this is happening.
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Old 04-18-2011, 11:53 PM   #51
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I'll recheck but dont remember black spots and rather grey than white. But that sounds like the behaviour and in that case the extended reach plugs won't help. So I would need one more step colder plugs? What everyone running these days?
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Old 04-19-2011, 11:33 AM   #52
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Quote:
Originally Posted by Spookyfish View Post
I'll recheck but dont remember black spots and rather grey than white. But that sounds like the behavior and in that case the extended reach plugs won't help. So I would need one more step colder plugs? What everyone running these days?
Mine look grey as well, but I thought that was the normal color. I'm running the NGK BKR7. Also curious if people have moved on to a different plug.
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Old 04-19-2011, 11:50 AM   #53
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Grey deposits are normal. If your plugs are overheating, they have a distinctive appearance. Here's a chart with some pictures:

http://www.spark-plugs.co.uk/pages/t.../diagnosis.htm

Anyway, pre-ignition gives similar symptoms to what you've described and is easy to check by looking at the plugs. If your plugs appear normal, I think you can rule it out.
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Old 04-19-2011, 03:30 PM   #54
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Pre-IGN: But always at the exact rpm spot? Really?
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Old 04-19-2011, 04:33 PM   #55
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Quote:
Originally Posted by Spookyfish View Post
Pre-IGN: But always at the exact rpm spot? Really?
It's related to heat being added to the plugs faster than the plugs can dissipate. RPM, spark timing and mixture are contributors (i.e., max temp and max pressure on the power stroke).

In any case, it's a binary test . . . when it happens, stop and check the plugs. If the plugs are normal (grey deposits are normal) then it's not pre-ignition from hot plugs -- which is a good thing -- other than the fact you're still searching.
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Old 05-07-2011, 07:17 PM   #56
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Re-doing the PCV and catch can to comcat that.

Could it be that my CAS is dying? How could it not be it?
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Old 05-08-2011, 06:47 PM   #57
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New combat plan:
- Check MSPNP: hardware latency, raise overboost protection
- Check air filter
- Check CAS wiring and (replace) CAS
- Remove/empty CAT
- Leakdown test
- New (race) plugs, heatrange 7, 0.8mm
- Remove PCV and add catch can

Suggested order in terms of likelyhood?
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Old 05-08-2011, 07:03 PM   #58
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I'm surprised you didn't try the range 7 plugs before. You may need to gap them a little more than 0.8mm. Btw the COPs are not THAT hot. They will still fail to ignite a mixture richer than 11:1-11.2:1 at boost levels more than 14-15psi. The stock 1.6 ignition will fail to ignite 11.5:1 at 14psi most of the times, but I've seen it fail even at 9psi and 11.8:1.

So do try to go a little leaner.
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Old 05-09-2011, 03:01 AM   #59
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Quote:
Originally Posted by Reverant View Post
I'm surprised you didn't try the range 7 plugs before. You may need to gap them a little more than 0.8mm. Btw the COPs are not THAT hot. They will still fail to ignite a mixture richer than 11:1-11.2:1 at boost levels more than 14-15psi.
?? News to me. The coils on the black car (off-the-shelf TSE COP kit) had no trouble on 100 octane at 240-250kpa and 11.2:1 AFRs - even when I was doing 5th and 6th pulls with 3.63s in the rear end.
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Old 05-09-2011, 03:08 AM   #60
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Quote:
Originally Posted by Reverant View Post
I'm surprised you didn't try the range 7 plugs before.
Tried 7-range before too, even extended reach version. Im afraid it's not THAT simple.

About the CAS-wire shielding. I suppose we're talking the plug on top of the CAS and the wired coming out of that? From where to where do we shield them? On my car they're pretty well taped in with other wires, such as the loose O2 connector.
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