A few weeks ago I ran my first dyno test. I mainly wanted to check my A/F ratio\'s, not purely hp numbers.
I went in looking to tune the ratio\'s in the 11.4 area but found out that the tuner\'s computer only plots CO% and Lambda graphs (not like they do in the States) Can anyone help me understand how to tune a/f ratio with system. The tuner does not specialize with rotary motors but he said I should be in the 5.5 to 6.0 range...which I was at 4000 rpm\'s but then it climbed after that. He said I was plenty rich, but until I better understand how to read A/F reading this way. I decided to stop there. Looking at my Lambda he also thinks my O2 sensor may not be working correctly? I am changing the sensor and I hope to make another dyno run soon.
Can anyone help me out here?
Thanks!!
I made 282.7 rwhp at 6185 (11.5psi or .79 bar) and 352.5 Nm at 4849 rpm
Co% and Lambda graph
Hp and Nm graph...sorry they are so hard to read.
From my limited knowledge thats very rich.
You dont want to be running at 5/6 AF. At top end, full throttle you want to be looking at around 9/9.5 and thats still on the rich side. Idle should be around 13.5.
Someone who has been playing with their PFC\'s and wideband please post some figures.
Dan
Thanks Dan!
Are there any tuners in the UK who can help me better understand how to tune with Co and Lambda?
The only person I have spoken to that might know tuning is Geff at Reworx, what do you think? or there must be some people on this forum who have dyno tested? How do you do it in the UK to read your A/F ?? if some could show me there charts, that might help.
Thanks again,
Oliver
I found some information with numbers on reading Lambda to a/f readings, near the middle of the page. Looks like a nice unit from australia.
http://www.techedge.com.au/vehicle/wbo2/info5301.htm
Still need to figure out how to us the CO chart for tuning????
Right, I shall do my best to help :)
Sorry in advance if you already know the basics, but I\'ll take it from scratch!!
First off, Lambda 1 = 14.7:1 air/fuel ratio, where a lambda of 1 represents the so called \'ideal\' air fuel mix or stoichometric value (sp?) for cars.
A lambda of 0.9 is the same as an air/fuel ratio of 13.23:1.....but....
Rotarys love fuel, and so do high boost applications, so you need to be richer than this.
When you are off boost ie in a vacumn or neutral state of driving you can aim fairly close to a lamda of 1, as the engine is off load, off boost and low throttle and hence not liable to knock. My car runs between about 14.1:1 and 13:1 off boost
On rolling roads, you are generally looking at the load area of your map, so you are looking to be richer still.
I would recommend aiming for 11:1 a/f or .75 lamda throughout your boost period throughout the rev range. Maybe go a little leaner at about 6.5k revs to about 11.5:1 or 0.78 lambda.
You could go leaner and generate a little more power with about 12:1 a/f or .81 lambda, but one reason that rotaries love rich fuel mixes is because the fuel is partly used to help cool the compressed air charge going into your engine, helping to prevent detonation.
Always err on the side of caution and run rich!
If you go too far rich, any more than 10:1 or 0.68 lambda, you car will start to stutter at about 6k revs (peak load for most rotaries), which will sound like a misfire.
Hope this helps!!!
Regards
Max
Nice info Max, always wanted to know the relationship between Lamda and Air/fuel ratios, and what is lean and rich for a Rotary
:cool
Lean is anything above 12.5:1 on boost and rich is anything below 9.5:1 on boost.
Dan
PS. I only quoted on boost, as we only ever drive them that way. ;)
I\'d be interested to monitor the A/F ratio on my car when it arrives. Is there a sensor on the car somewhere I can use? Can I monitor the gas out the exhaust? Would ideally like to watch it while I\'m driving. Not particularly interested in getting it done on a rolling road.
I see there are several devices for monitoring the data in the ECU, can I take a reading from there, or do I need a special ECU?
Sorry, but my knowledge is pretty weak when it comes to ECUs and the like.
The stock oxygen sensor is a very basic narrow band item - totally useless for tuning.
You need a wide band lambda sensor (and some thing to see the readings it\'s providing on) in order to see whats going on A/F or Lambda-wise.
Max has the MoTeC PLM (professional lambda meter); this is a pucka WBo2 with its own LCD display. They go for between £750 and £1000. You can get cheaper widebands for upoward of about £450 I would say.
Not cheap then :rolleyes:
R.
looks like we will be renting off Max then, how much ya charging Max??? lmao
Thanks Max and everyone for your help! :)
I didn\'t understand the ratio relationship between Lambda and A/F reading until I found the Tech edge website the other day. Now it\'s very clear, and I appreciate the added info Max and Fish. I have always been able to get straight A/F reading from the dyno\'s in the States. But like I said, found out it\'s not done the same here in Denmark.
Fish-
I am still a bit confused with reading C0%?? When I wote 5.5 to 6.0. I was speaking of CO%. I think you thought I was saying A/F ratio?? From 4500 to 6000 rpm\'s I was near or at 9.0 on the CO%. Everyone here thinks that is rich?? But if you look at my Lambda at 6000 rpm\'s. I am Lean at .85.
One more thing. I veiwed my video tape of the dyno test and noticed the Lambda sensor was coming out during the pull. Maybe?? this had a effect on the reading?? not sure.
I also changed my O2 sensor today. Using my O2 sensor volt readings.
- at idle (with lights on) 0.07 V
- 4500 rpms, 4th gear, 12 psi 1.09 V
Anyone with a PFC ...are you seeing the same volts on the O2??
After work today I visited a friend who just installed the Tech Edge WB unit in his Subaru WRC. It\'s very nice and I ordered one for myself today. This unit should make dyno testing, track days and even emission testing a hole lot easier.
Still, if anyone can explain CO% reading while I wait for the unit to arrive, I would appreciate it.
Thanks again
Sorry for the confusion on my part.
Here is another Wide Band unit from the States.
http://www.innovatemotorsports.com/lm1.php
Here is a group buy for those who don\'t visit the RX7Club forum?
http://www.rx7club.com/forum/showthread.php?s=&threadid=220439
CO (carbon monoxide) and CO2 (carbon dioxide) are directly related to air fuel ratio.
As a general rule, as CO goes up, CO2 will go down. It is possible to use conversion tables to convert your CO content or CO2 content to an air/fuel ratio.
This method is only generally used for setting up vehicles to within manufacturers tolerances (where they normally quote a standard CO or CO2 level).
For tuning, a good wideband (oxygen sensor) setup is far more accurate.
Hope this helps a little!
Regards
Max
A CO closer to about 7 would put you more in the ballpark for tuning,but as max has said you are better off using a wideband.
From the voltages you are getting from a stock sensor and pfc, you are rich .95v is a ballpark figure, but DO NOT tune with the stock sensor.(These figures are guides and will vary from car to car)
Jason
Have you still got a cat? and where did you take the readings from?
QuoteOriginally posted by maximtaylor
CO (carbon monoxide) and CO2 (carbon dioxide) are directly related to air fuel ratio.
As a general rule, as CO goes up, CO2 will go down. It is possible to use conversion tables to convert your CO content or CO2 content to an air/fuel ratio.
This method is only generally used for setting up vehicles to within manufacturers tolerances (where they normally quote a standard CO or CO2 level).
For tuning, a good wideband (oxygen sensor) setup is far more accurate.
Hope this helps a little!
Regards
Max
It helped! :) Thanks Max
Hopefully my own WB on the way. It will help make my tuning a lot more precise and accurate.
QuoteOriginally posted by JayDee
A CO closer to about 7 would put you more in the ballpark for tuning,but as max has said you are better off using a wideband.
From the voltages you are getting from a stock sensor and pfc, you are rich .95v is a ballpark figure, but DO NOT tune with the stock sensor.(These figures are guides and will vary from car to car)
Jason
Have you still got a cat? and where did you take the readings from?
So, 7.0 CO is ball park. The tuner thought I was lean from 2-4000 and rich from 4-6000 rpm. Thanks Jason. Atleast I have some idea of CO reading.
The reason I posted the PFC volt readings. I just changed my O2 sensor and it is reading the same as the old O2 sensor. I was hoping to hear what others see on there PFC\'s. Just for reference purposes.
I have just installed a Knight Sport Metalit catalyzer (high flow) and the dyno reading was from a Wide band in the tail pipe. I will have my own WB in a few weeks and will have a better idea what\'s going on so, I can tune it right for the next dyno run.
Thanks again Jason
I use to see .95 on the pfc but on my car that is still slightly rich.
You will want to place the wideband in front of the cat.
Unless your wideband has a temp compensation I would have a bung placed in the bottom of the downpipe, if it has you can put it in place of the stock one, and turn O2 control off in the PFC.
The leanness maybe from the airpump giving you a false reading low down, it does cut off at @ 3000 I think.
Also be wary of wideband that are not yours, we have had someone\'s DIY reading 16.1 A/F ? full thottle, mine read in the 10\'s
Jason
Here is some good information on wideband and A/F stuff. (http://www.nopistons.com/forums/index.php?showtopic=25103)
Taken from NoPistons forums.
Dan
I have moved this as it covers both T11\'s and FD\'s, and the information is of a general(ish) nature.
Dan
Hi.
Have any guys out there in the UK bought a wideband meter from the USA? If so, how much customs duty did you have to pay? I just wanted to know how much the thing will cost in all.
Thanks
Trev
Fish - Thanks, I found this on the thread you posted. Some good basic info... helped me understand things a bit better.
http://auto.howstuffworks.com/framed.htm?parent=question257.htm&url=http://www.interro.com/techtips.htm#anchorchart2
Jason - I was thinking about attaching the wb sensor, 5-6 inches down from the DP / HF flange. Just before the high flow cat. The air pump does cut off around 3000...but maybe I have a bad ACV? A few weeks back, I posted a thread about my metering oil nozzle may be faulty. I have since purchased 2 new nozzles from Jimmy\'s in the UK. I have read that if not working correctly it can have an effect on emissions? Will fine out after they are replaced?? My plan is to change the nozzles (top of the rotor housing... :( ) and hopefully the WB will arrive soon after and give a second go at the dyno.
P.S. Is that your engine compartment in your photo?? if so, looks very clean!:) Also, do you have a WB unit?
//Oliver
Yes that is a good place to mount the sensor. I don\'t think it would be your ACV, see what readings your wideband give.
With the wibeband in the tailpipe you can get false readings especially if you have a big exhaust tailpipe, at low air flow.
Yes I do have a wideband and datalogit.
Thanks for the comments on my engine, I have just got to make it go as good as it looks now. (must beat Evil rotor on Oct 12th):D
Jason
What, with that little rotary choker you call a turbo!
We shall see!!
You sorted my part yet?, so I can beat you:D
Just remember the wideband and datalogit are in my hands;)
You know I am not worried about this engine, going to have some fun finding a limit!
Your motor wont spool till Bristol
QuoteOriginally posted by JayDee
Your motor wont spool till Bristol
Is that after leaving from Glasgow???
Dan
You just wait until Mr Apex seal says hello to Mr Exhaust turbine, and then we will see if the roller bearing was a good choice!:rollin
maybe, but as long as it lasts one run:cool
ported engine, bigger turbo here i come
In light of your recent comments, i have to inform you of a new delivery date for your parts, this will be the 13th of Oct.:wave
no matter, you will still be left at the starting tree. with other mod you dont know about:bandit
Anyway back to the thread Oliver do you have datalogit?
It makes tuning alot easier
Jason
Unfortunately, I do not have Datalogit. It has been on my list of "must get" for over a year but keeps getting switched back to my "down the road" list :(
I have been trying to save up for a laptop but keep spending money in other places.
I do look forward to having it one day. When that time comes, I would like to talk with you.... if that\'s ok?
Any chance we could have an update after the Oct 12th challange between you and Evil Rotor?? :D Maybe a new thread with lot\'s of photo\'s or even a video!!!
I installed my new Tech edge Wideband unit a few weeks ago. If anyone is interested in this unit. Here are some group photo\'s showing how I installed mine.
After installing the wideband unit. I made some runs on the Motorway. Added and removed fuel where needed and took my FD back to the Dyno. I was able to get 20 more Horsepower at the same boost (0.79). I very happy with the new wideband unit.
Nice job Oliver :)
It was worth the money!
Regards
Max
And I have just placed my order for one of these units. Looks like its money well spent.
Good job Oliver, keep us updated. :)
Dan
As I\'ve been telling you all along, its a top toy and all cars should have one.
If you want to play I do still have a loan unit available.
Bill
Thanks Max and Dan :)
Without a doubt, it was well worth the money and peace of mind knowing my A/F ratio\'s on the street and mostly on the dyno are safe.
I was happy after my dyno run. I would be lying if I said I didn\'t want to up the boost alittle :D But I have decided to build my power slowly with what I have. I hope to keep my FD for a LONG time.....so I am not in a hurry to get 400hp. One day would be nice... before my kids are old enough to drive my car!:rollin
Dan - my WB arrived within 10 days ... let us know how you like it.
Best Regards/
Oliver
Where are you plumbing in the wide band ?
pre or post cat ? (or do you not have one)
I placed it around 6 inches behind the flange on and before the High Flow Cat. Positioned it at 12 o\'clock.
sorry forgot the photo........