During a quick shift on the 2-3 gear change. Do any of you guys experienced a slight lag then power comes back. I land the gear change around 5k and that is the activating rpm for the opening of the vim. Is it my clutch or an unfavorable rpm to open at? I have had it at 53k and 52 and the slight lag was still present. Suggestions welcome.

Thanks

Iilac

 

you still running the stock clutch?

 

yea, the clutch issues would depend on...what clutch you use

 

I am on the original clutch at 58k. However, I have done the 5th gear in low speeds clutch test to see if the rpm and speed goes up and it pass it with flying colors.

 

does the car rev a little higher than usual and lag, or does it bog down?

 

no, as I shift from the 2 to 3, it lands at 5k and the rpm continues to climb but I can feel a slight lag then full power comes back. It feels like an unsmooth power curve from closed butterflys to open butterflys. That's the best way I can describe it. It's a slight lag and I was wondering if it was just my clutch, my vim or the harlan taking a few seconds to open the vim or it is normal with the jwt/mevi setup.

 

so like it bogs down? that makes it sound like its NOT a clutch issue. If your clutch was bad, the power would come on, and make it slip a little (revs would climb, but car wouldnt lag) Sounds maybe like your switch has a problem, or its a natural lag.

 

Yeah, a slight bog. I just wanted to know if other people with the jwt/mevi setup have this too. Please chime in. Thanks for your help SXN.

 

yea, i can help with the clutch, but not with the mevi. sorry man, glad i could help a little, i would rule out clutch problems

 

Sweet!! I'm not the only that feels this

I know exactly what he's describing. You wind out 2nd and then grab 3rd and there's a momentary bog. It's enough that it feels like you've let off the gas. It only happens on rare occasions in my car and seems to happen more when I shift slower into 3rd and oddly, going down an incline. I've never experienced the bog at the track, thank God.

My guess is it's the Harlan switch being slow to react to close the butterflies when the rpms drop below your switchover point. What we are feeling is the butterfly valves suddenly closing shortly after grabbing 3rd which causes a wave of turbulence in the intake manifold and possibly F-ups A/F ratios for a slight second. My reasoning behind all this is that I can manually operate my VI with a toggle switch and I can induce the same sensation.


Dave

 

see, it is fine said it wasnt the clutch

 

OMG!!! This is funny. I get the same thing sometimes, maybe on 1 in 10 times I wind out 2nd and to into 3rd. And it's only going into 3rd, no other gear.

Always thought it was my 12lb flywheel causing my rpms to drop too fast between shifts. I got the flywheel intalled the same week I got my ECU from Jim Wolf so never thought about it being anything but the flywheel.

I also thought it could have been the clutch, but it's brand new and will chirp second like a champ and lets me pull 2.1X 60's, so the clutch causing the hesitation made no sense.


Same as Dave said, it has never happend at the track. That must be becuase I am ramming through the gears so fast the butterfly valves don't have a chance to close.


Hahahahaha.....thanks for posting this thread Iilac.

 

Ha, that's good to hear that it's just not me. Thanks to everyone for your help.

 

shift faster

 

My car does the same thing. Do I need to shift faster too


I get this but under slightly different circumstances, I get it under hard acceleration when I shift, but not totally WOT shifting. I can create the sensation myself if I manipulate the throttle just right on the upshift, but I don't know if I've ever had it happen as high as 5000 RPM. Usually for me its like 3k-4k, when I'm on the gas more than normal but not totally WOT. I don't recall when this first occurred but now that you mention it it has just been within the last year and a half while I've had my MEVI and JWT, not sure if it ever happened before I had the JWT installed though. It doesn't really bother me it just strikes me as odd sometimes. I can cause it or prevent it pretty much at will depending up how I manage the throttle on my upshift.

 

You should probably set the VI to open at a higher RPM. I know that if the VI opens too early, the engine feels like its hitting a brick wall.

 

my VI opens at 5200

 

there were occaisions when i got this as well. IIRC...it was when i was under casual high rpm driving. not full out race throttle if that makes any sense.

like neal said it was more around 4k not 5k and under "getting on it throttle" opposed to "full race throttle".

--Paul

 

Yeah, I've seen that bog down too. If it's too slow of a shift it'll usually do it. My VIs set for 5000 and don't really see any problems with hard accel as long as the shifts are quick.

 

Same here, just like we talked about last night. And I tried it today and I dont get that bog anymore. I think it was just the harlan.

ps - we are not alone.

 

deezo- I have had it at 5k, 53k and 52k and the bog was still present. I wonder if the summit has a faster activiting time then the harlan? Is that possible or is the difference not measureable. Ha but yeah, it's good to know it's just not me.

 

I use a summit