Possible flat spot

toppertee · Postby **toppertee** » Sat Mar 31, 2012 8:25 pm

You want to try a NA6 it's got a big flat spot right up to 5500rpm :wink:

JRBasia · Postby **JRBasia** » Sat Mar 31, 2012 10:18 pm

All the more reason to fang it xD

I also experience exactly the same characteristic in my NA6. between 2500 and 3000 rpm there is a noticeable flat section at anything less than WOT within the first 5 minutes of driving in the morning. After that it's all good. Mind you I have full exhaust system but stock intake atm.

Postby **Okibi** » Sat Mar 31, 2012 10:57 pm

JRBasia wrote:... anything less than WOT within the first 5 minutes of driving in the morning...

That's probably your MX-5 doing its best to save its own life while your pushing cold oil around the engine. :mrgreen:

93_Clubman · Postby **93_Clubman** » Sun Apr 01, 2012 12:55 pm

Okibi wrote:I was thinking perhaps the intake butterflies might have been "sticking" a bit but I think they open at a higher RPM.

Yeah, VICS activates at about 5500 RPM.

jonosx · Postby **jonosx** » Wed Apr 04, 2012 7:00 pm

Yep i have a similar flatspot around the 3K mark in my nb8a.

Only when the engines cold. It sems to be exagerated in the colder months. By the time the temp gauge reaches normal operating temp its gone.

I've swapped and changed many things (throttle body, iac, engine) but its always been there. Havent been able to try a different maf or ecu yet though.

Zcootz · Postby **Zcootz** » Wed Apr 04, 2012 11:52 pm

I'm feeling a lot happier to hear that others are having a similar experience. This does make me think that this might just be a design side effect that is highlighted when running cold.

kurumasen · Postby **kurumasen** » Tue Apr 10, 2012 5:08 pm

Me three, I've had mine for a month now (NB8A, also 130k kms so pretty comparable to yours) Mine is definitely noticeable when its cold. I've got a bit of a hill that I usually head up within a couple minutes of starting up. At 2500-3000rpm I can feel its being sluggish like it doesn't want to pull regardless of throttle position and then after about 3300rpm more torque would kick in (kinda like really shitty vtec that goes from 'I cant do it' to 'ok lets get moving')and then it'll giddyup and go. Then when it starts running normal operating temperature it seems to go away and the car runs like a gem and pulls smoothly thru the rpm range.

I've checked the plugs and they're iridium ones in pretty new condition and I've also cleaned the carbon deposits out of the TB with carby cleaner. Next I'll think i'll check the vacuum operated manifold butterflys that are supposed to help swirling at lower rpms. Does anyone know how to check if they're operating as they should, like what rpm should it kick in at? I've had a quick look and blipped the TB whilst checking to see if the vacuum actuator moves the rod, from what I can see, I don't think its doing anything.

hks_kansei · Postby **hks_kansei** » Tue Apr 10, 2012 6:00 pm

93_Clubman wrote:
Okibi wrote:I was thinking perhaps the intake butterflies might have been "sticking" a bit but I think they open at a higher RPM.

Yeah, VICS activates at about 5500 RPM.

Kurumasen ^