Perhaps you're doing something I'm not but that's at the absolute edge of the engine running. It's just too little fuel. I can see possibly rapidly dipping down into something that lean while using an aggressive O2 loop during highway driving but not at idle unless it's dipping up and down, too.

B

 

my big streetport T2 runs fine at 15.5:1 , on the highway at least. but as engine load increases or vehicle speed decreases, you have to richen it up or you get the bucking and hesitation you are talking about.

 

What features does the ol' Microtech have as far as closed loop tuning and adjusting the trail split timing according to load?

 

It doesn't have a closed loop function. The only function I'm aware of it has is it does detect steady load and will remove x % of fuel out on a separate tuning page. Kind of goofy IMO but better than nothing.

B

 

keep it coming. some good information here

 

Well Westbrook's engine runs in the 17's AFR but he said he could run it at 18 if he wanted to but he has his perfect where it is now, while I want to get the best gas mileage i can in the highway because I have a good 60 mile drive to and from Houston. Driving to/from Houston allot like i do I wanted the best mileage for that.

My wideband seems to be working fine, and had been backed up with Westbrook's wideband on the back end of the exhaust so it is showing correct AFR's. So that means that my engine is running the 18 like my Wideband is showing.

Just to add, you have to be out of the twin throttle and only on the primary throttle, so that all the air is going thru the primary intake ports.


Yep there is allot of info

 

Sorry Chuck, I don't mean to be disagreeable or bring a negative tone to this thread, but I don't buy it. It's far too lean on both counts; the engine won't run that lean no matter when you fire the plug. I question the accuracy of the sensor that's being used there to ascertain the ratios you guys are seeing.

B

 

Agreed. Engine will misfire above 16.5:1. Possible air pump diluting the exhaust?

That, or verify your wideband against another.

 

My thoughts are it's the latter although exhaust leaks aren't exactly uncommon. In my time going around and about to different places and cities to tune cars, I've run into alot of issues with wideband inaccuracies with both enthusiasts' cars as well as some dyno shops' sensors. There was one time where I used my old, clunky PLX M-200 to verify that the new-ish sensor at a Dyno shop in OH was bad. I know some of this topic of wideband sensors has come up from time to time on the forum, but in my experience I've seen the Bosche sensors being pretty bad wth the AEM wideband unit itself being the all-time worst. Maybe there's a reason why there's such a big price difference between the NTK and Bosche sensors...

B

 

On the highway, that's not surprising. I get that or a little better on the highway as well. It's the city that's the issue. High overlap ports suck in stop and go traffic.

I keep floundering between using the Kiwi kit or using my own setup. There are advantages and disadvantages to both. On one side I could say that I did it all myself. On another side there aren't any unknowns when using an engineered kit.

It's actually quite happy running 15:1-16:1 under light accell, but feels incredibly anemic. Compared to a richer ratio it takes a lot more throttle to accomplish the same thing, with no improvement in mileage. Even though it's burning leaner there's far more load on the engine.

Which one is for a half bridge?

Sadly, the Microtech has no provisions for closed loop. Microtech has been promising a software update for damn near 4 years yet we've not even seen screenshots of a beta/alpha version. The LT16 is due out anytime (or so I have heard) which probably means the software will be available soon.

It's a bit annoying, but you also lose the cruise functions when you switch to matrix mode.

 

My FD will cruise at 17 AFRs at above 3000 rpms fine in cool or dry weather. If hot or warm and humid it will buck a little sometimes when lightly lifting the throttle.
Thus I only run them in winter. I just turned them down to 16.5.

I have seen higher cruising 18 AFRs a little but they are not a reliable to cruise as they are too lean.

TII primary coil, HKS Twin Power, Taylor very low impendance plug wires, D9EGV plugs gapped at .030".

I am out of this thread and will not respond any more to it.

 

Bridge if not DD.

 

Pp