It has been a while since I have asked for help. I now have my Lotus Seven Replica (13B 6-port) licensed on the road. I have a MS2 and just downloaded the 3.1.0 firmware. I am controlling the fuel pump speed and the aux ports from the MS. I am starting the task of tuning under load. It is running fine at low speeds and low loads. I have been driving around the neighborhood making some corrections manually by editing the VE table. My current method takes 2 people, one to drive and the other to watch where in the VE table I am running when things need improvement. While I am making progress, I still have a large amount of tuning to go and sometimes see AFR’s in the 17 range. I don't think this is good, but I don't really know. I can see that this trial and error tuning would take a large amount of time. I could just do some logging I suppose, but why not just jump directly to the 21st century? I want to attempt using the “VE analyze live” function of Tuner Sstudio.

From what I read about it, I set up the AFR table, then enable the VE Analyze function. Where I am unclear, is where do I start with filling the AFR table values? Will this table be basically the same values for most rotaries while the VE table would vary depending on engine variables? What are good values to fill the AFR table? Do you recommend just letting the Tunerstudio just automatically update or should I review the numbers before sending the data to the MS? Right now when I burn corrections to the VE table, the engine stutters a bit during the transfer. Is this normal? Will it be worse if I let the automatic function send info to the MS? Any recommendations for the “Advance Settings” tab in VE Analyze now.

I know it is a lot of questions but, I can’t seem to find anything about the starting points directly rotary related.

If it helps any to see what is different about my setup, I have posted a pic of the 13b in the Se7en. It has a custom log-intake with a Ford Taurus throttle body and a custom header with a resonator and a turbo muffler.

Thanks
Chuck

 

79 readers so far and nobody has any input?

I could really use some advice or encouragement.

 

I just do datalogs. then look them over megalog viewer use the analyser in there. I don't trust it to do everything I just use it for comparison and small quide. Nothing is better then getting a dyno and tuning your self. If you dont get a dyno find a long hill and do 4th gear pulls from 2500 to redline.(if road are safe to of course) This is the same as a dyno. Log the run,pull over and make changes.

As for a/f rotaries like richer mixtures for driveabilty 12.5 under high loads for N/A. 13.5 for light loads. Hope this helps.

 

13bdarren, thanks. I suspected that most rotary tuners directly adjust the VE table based on the threads I have read here. I haven't seen anything on this board about using the self-tuning feature in TunerStudio. I have read many other sites where tuners just let VE Analyze Live do its charm and get good results. I tried it out yesterday using Aaron Cake’s AFR table suggestions.

I have to say, my results were mixed. While the software clearly worked as advertised, it required the use of a properly filled AFR table. Knowing what the right AFR values for various operating conditions is the challenge. I guess that is where I was looking for some input.

VE Analyze Live ran and in the areas where I had good AFR bins it worked fine. I found out quickly, that my engine doesn’t like some of the values in the AFR table from Aaron’s write-up. It may be due to my engine being a NA where his was a turbo(?), or maybe the differences in intake manifold and header setups. The low load and cruise areas where he suggested leaner than stoic settings needed more fuel. I manually adjusted the VE table bin numbers a bit higher and it ran better. I’m not exactly sure where the AFR is running now, but the car runs better. I guess I either dial in the tune by using the AFR table then running VE Analyze Live or directly in the VE table. My feeling is that it doesn’t really seem that one method is clearly better then the other. If my plan was to run the MS in closed loop mode with the wideband O2 after dialing things in, adjusting the AFR table would make more sense. I may change my mind as I work with it a little more. I still have a long way to go…..

 

Keep in mind that ignition timing can have a huge effect on how drivable a tune is.

Ken

 

I noticed you manifold is a little modded. That might have a great deal of effect on your car drives. The stock TB is progressive when it open so you may need to tune thing different then most setups. Also look at your logs and see what your accel enrichment are doing. With that on make tuning a little tricky. Turn it off and do long pull slowly to get the whole rpm range in datalog. Then gradualty step on it more to get high loads. That should get you real close so that your not tuning against accel enrichments. Then you can turn it back on and play with that.

Every setup requires different things to work. Sorry I can't tell you what numbers to use for ignition or the accel. Just takes a lot of seat time to get it tuned. All I know is my car would drive terrible with any a/f over 14 it liked pig rich to drive smooth. Post some of your msq and datalog for us to see if we notice anything that might help.

 

Sweet car by the way. Would love to something like that with turbo engine mmmm

 

Ken, I used Aaron’s ignition timing table as a starting point. Is that a good starting point? I’m not sure how to “feel” the difference between timing and fuel needs during a seat-of-the pants tune. Can you provide any suggestions?

13bdarren: Yeah, the intake manifold is just a bit different than stock. The upper S5 manifold was chopped up and re-designed to get the overall engine height from oil pan to manifold to around 21inches. This was needed to fit under the hood of the Seven. And then there is the aux ports being powered with a ford lumbar seat pump. I’m also not exactly sure what parameters/settings to use to trigger the aux ports or the 2 speed fuel pump. Right now they are set at 3800 and 3000 RPM respectively. More differences there too I suppose. I have no reason to expect my VE table to be similar to any other stock N/A. But for some strange reason, I half-expected that the AFR needs should have been similar. I guess I was wrong. So be it.

I was trying the VE Analyze Live because it is supposed to take into consideration the accel enrichment and other setting like decel. I wish I had some good long hills to tune with. I am in the middle of flatland country. Everything has to be done on a relatively flat road. I’ll have to do some trial runs with the accel and decel turned off.

When I get some more time to work on the car and a bit better tune, I will post the msq and a log.

Thanks for the compliments. Building a car from scratch was a huge undertaking for me, I had a lot of new challenges. I had to learn suspension design, power train packaging, had to meet state licensing requirements for a homebuilt, performed my first rotary engine rebuild and had to learn about EFI. It was a true homebuilt car, not a kit. With the total car weight down around 1250lbs and the N/A engine, I calculate 0-60 times in the 4-1/2 second range. That is once I get a good tune. Not too bad for a N/A powered car? Not to mention I already had access to the N/A power train. So turbo power was not in the cards.

Just to satisfy your curiosity, here is a link to one builder who did just that with a twin-turbo Cosmo engine. http://www.mindspring.com/~robmk2/

Thanks,
Chuck

 

I think aaron's table is for a turbo engine? I typically tune a little differently for NA. Generally I've noticed that for smooth running (on my S4 NA) you need a bit less timing at the lower left of the table.

It leads to a weird looking table, but it seems to run more smoothly.

Ken

 

Hey guys, thought I would add my query on to this thread rather than start a new one.

I too would love to know any recommendations for my AFR table. I have just about run my engine in and I'm looking to finalise the tune shortly so I want to get my AFR table dialled so I can get a lot of it done using the VE Analyze Live then do the finishing touches manually.

The problem is that my motor is a 13b bridgeport (N/A) and I have found it a bit tricky to get straight answers regarding my setup. All the low-down stuff is a nightmare with this motor as it's just so grumpy, you sure can't go off the AFR readings.
I'm running MS2 extra using a twin 50mm IDA style throttlebody with 4 rx7 550cc injectors - tuning with Alpha-N.

This is the AFR table I have been using (well sort of, I've been tuning manually)


Any suggestions you could give me on how my AFR table should be would be excellent, even any TPS/Alpha-N specific tuning tips would be greatly appreciated as I understand you have no effective WOT to go by either. Can anyone confirm that if I push the throttle too far under a certain condition, I'll end up tuning the wrong part of the map?

 

I would not tune alpha-n at all. Also, you should probably make the lower left part of the table considerably more rich. I typically idle around 12.5:1 on most rotaries that I have tuned.

As far as timig on NA vs Turbo, I generally use less advance across the board on NA engines, with a further dip around idle for smoothness purposes.

Ken

 

Thanks for your input Ken, it is much appreciated.

Although it is widely accepted that bridgeports should be tuned with Alpha-N due to the poor map signals they produce. I initially persevered with speed density, but it was hopeless on this motor.

These are my inlet ports, all 4 of them are this size.


Also, I failed to mention in my previous post that my AFR table is configured to what appears to be lean in the bottom left due to the misleading readings I get on the wideband due to the bridgeporting. However, do you think I should richen it up just after idle so that once it's under load it has the correct richer mixture? As I have always had a lot of trouble transitioning from closed throttle to part throttle - stumbling.

Aside from the lower left, the rest looks ok to you? I was thinking it's a little on the lean side, but what are your thoughts?

 

When you tried speed density, did you use ms2/extra's MAP sampling timing? Did you try to adjust it? Also, you may want to try one of the blended table approaches. This would allow for things like speed density at low load and alpha-n at high load.

Ken

 

Looks fine to me. I might richen it up a little at higher throttle positions. 13:1 is safe for an NA but I usually tune slightly richer which reduces EGT without affecting power.

For off idle, I would make the areas above idle and to the right of idle, and in between a bit richer. Also, ignition timing can play a big role in drivability, especially in that area.

On my stock port rotary, it liked the idle area and the area around it to be rich too.

Ken

 

I updated my AFR table to look like this.



Went out a couple of times using VE Analyze with decent results. I didn't spend as much time on it as I would have liked though. The thing pulls like a fucken freight train! even though the AFR's aren't bang on yet.

What do you mean by map sampling timing? Not quite sure what you mean sorry.

Before I started tuning Alpha-N, I read a good write-up on the blended maps and it seemed like a viable option, but it was too complicated for me at the time so I stuck to straight TPS. It may be something I look into, seems like a good compromise.

Timing is a tricky one with bridgeports too, without a dyno I'm flying in the dark a bit, but I think my timing is ok. If anyone has any suggestions for my timing map that would be great too.



I know there's a big jump in my timing table down the bottom, do you reckon this should be more linear?

 

Ms2 extra samples the MAP sensor on a rotary every 180 degrees. You can set the exact point at which it samples to get the best signal.

As far as your timing, smooth and linear will make the car more drivable, but do whatever works for that engine. It will be hard to tell exactly what is best without some time on a load-holding dyno like a mustang eddy-current dyno.

Ken