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should I bridgeport or streetport?

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Old 03-20-08, 12:58 AM
  #51  
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Originally Posted by scathcart
I've passed cars through emissions running at 16.2:1, at a 1500 rpm idle and at cruise. O2 sensor was placed ahead of the air pump feed, so exhaust dilution is not a possibility. Most engines were done on an FJO using the NTK sensor, one on an AEM unit. Swapping in a Motec wideband unit in one car at another date showed identical readings to my FJO. It yakes some fiddling with the timing, but it will run.

It is amazing how low the emissions will get running the engines like these. Every time I have to laugh at the readings of 0.00% for Carbon Monoxide.

For regular highway cruising, the engine will run stabily around 15.5:1 AFR's without misfiring.
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
Old 03-20-08, 01:57 AM
  #52  
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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.
Old 03-20-08, 02:47 AM
  #53  
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What features does the ol' Microtech have as far as closed loop tuning and adjusting the trail split timing according to load?
Old 03-20-08, 11:03 AM
  #54  
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Originally Posted by Slammedblk7
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
Old 03-20-08, 11:55 AM
  #55  
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keep it coming. some good information here
Old 03-20-08, 12:23 PM
  #56  
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Originally Posted by BDC
You need a new wideband sensor/controller or there's something screwed up somewhere, Chuck. The engine won't run at 18's:1. It barely runs at low 15's as it's starving for fuel. There's hardly enough to light it at even 15's:1.

B
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.


Originally Posted by FC_boi
keep it coming. some good information here
Yep there is allot of info
Old 03-20-08, 02:53 PM
  #57  
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Originally Posted by Rx7_Nut13B
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
Old 03-20-08, 04:42 PM
  #58  
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Originally Posted by BDC
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.
Old 03-20-08, 07:06 PM
  #59  
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Originally Posted by scathcart
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
Old 03-21-08, 10:49 AM
  #60  
Engine, Not Motor

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Originally Posted by Rx7_Nut13B
Hey Aaron,
I get over 25mpg @ 80mph with my HBP REW, Around that speed the timing is 38 degrees advanced and about 18.2-18.8AFR
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.

Originally Posted by Sideways7
Dear God, man! So are you doing the Kiwi-re 4-rotor?
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.

Originally Posted by BDC
15:1 is barely enough to keep the engine running. May be able to get away with it realistically while cruising on the highway with some aggressive O2 loop but it won't work when under any load other than that. The engine will buck and stumble.
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.

I think I've got some of my maps up on my website. Let me link what I have. They're for Haltech E6K/E6X and PowerFC. I'd bet you'd do better with the Haltech stuff. I made some different ignition curves I've pretty much stuck with. Been goofing with that for about 4-5 years now for the partial bridge. This is however for the 4-port turbo block. Download the JPBP1 map and load it up in the Haltech E6X software:
http://bdc.cyberosity.com/v/Technica...h/HaltechMaps/
Which one is for a half bridge?

Originally Posted by Slammedblk7
What features does the ol' Microtech have as far as closed loop tuning and adjusting the trail split timing according to load?
Originally Posted by BDC
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.
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.
Old 03-21-08, 08:02 PM
  #61  
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Originally Posted by BDC
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.
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.
Old 03-21-08, 08:26 PM
  #62  
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Bridge if not DD.
Old 05-18-08, 03:49 AM
  #63  
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