DTA s 80 with twin lambdas
Discussion
Hopefully I can get a bit of help here ..
I have a car in with a dta s80, it is configured with 2 lambda sensors.
The dta manual is of little help with my particular issue sadly, and my localish dta reseller isn't answering the phone so ..
On the real time display I can see a read-out for lambda 1 voltage, but how do I see what lambda 2 is doing? Is there a way to modify the real time display to read the outputs from both lambda sensors? or where can I see the lambda 2 output?
Also there is a lambda adaption table (essentially a self-learning table) but does this take an average from both lambdas? or only lambda 1? It "looks" like it takes readings from lambda 1 and uses that to update the adaption table, then lambda2 voltages are used to trim the other bank "on the fly" but it seems that bank doesn't have it's own adaption table?
Hope that makes sense ..
I have a car in with a dta s80, it is configured with 2 lambda sensors.
The dta manual is of little help with my particular issue sadly, and my localish dta reseller isn't answering the phone so ..
On the real time display I can see a read-out for lambda 1 voltage, but how do I see what lambda 2 is doing? Is there a way to modify the real time display to read the outputs from both lambda sensors? or where can I see the lambda 2 output?
Also there is a lambda adaption table (essentially a self-learning table) but does this take an average from both lambdas? or only lambda 1? It "looks" like it takes readings from lambda 1 and uses that to update the adaption table, then lambda2 voltages are used to trim the other bank "on the fly" but it seems that bank doesn't have it's own adaption table?
Hope that makes sense ..
spitfire4v8 said:
Hopefully I can get a bit of help here ..
I have a car in with a dta s80, it is configured with 2 lambda sensors.
The dta manual is of little help with my particular issue sadly, and my localish dta reseller isn't answering the phone so ..
On the real time display I can see a read-out for lambda 1 voltage, but how do I see what lambda 2 is doing? Is there a way to modify the real time display to read the outputs from both lambda sensors? or where can I see the lambda 2 output?
Also there is a lambda adaption table (essentially a self-learning table) but does this take an average from both lambdas? or only lambda 1? It "looks" like it takes readings from lambda 1 and uses that to update the adaption table, then lambda2 voltages are used to trim the other bank "on the fly" but it seems that bank doesn't have it's own adaption table?
Hope that makes sense ..
As you may know DTA has changed hands recently so any response direct from them will be slow.I have a car in with a dta s80, it is configured with 2 lambda sensors.
The dta manual is of little help with my particular issue sadly, and my localish dta reseller isn't answering the phone so ..
On the real time display I can see a read-out for lambda 1 voltage, but how do I see what lambda 2 is doing? Is there a way to modify the real time display to read the outputs from both lambda sensors? or where can I see the lambda 2 output?
Also there is a lambda adaption table (essentially a self-learning table) but does this take an average from both lambdas? or only lambda 1? It "looks" like it takes readings from lambda 1 and uses that to update the adaption table, then lambda2 voltages are used to trim the other bank "on the fly" but it seems that bank doesn't have it's own adaption table?
Hope that makes sense ..
You may get some response on the forum though ( or may not )
http://www.dtaforum.com/index.php
But what you're saying sounds about right.
Only one table is needed really, as you would not have both banks targeting different values, so the generic correction map should be more than adequate.
And no, real time display cannot be modified or changed, your only option to see what both banks are doing would seem to be via the logging.
Perhaps this is something Alex can look into for the future.
the car has an 8 throttle body inlet on it so two adaption tables would be great but doesn't look like it's on offer in the s80. If it was on a plenum with a single throttle then one adaption table would be fine. thanks for the reply stevieturbo. I might try a post on the dta forums too just in case someone knows a secret check-box hidden in there 
spitfire4v8 said:
the car has an 8 throttle body inlet on it so two adaption tables would be great but doesn't look like it's on offer in the s80. If it was on a plenum with a single throttle then one adaption table would be fine. thanks for the reply stevieturbo. I might try a post on the dta forums too just in case someone knows a secret check-box hidden in there
Again, there is only one fuel map, so it would make no sense for two learning tables. As for two learning tables, that would then require two fuel maps, one per bank. Which just doesnt happen.You can of course have individual cylinder trims, as well as the closed loop lambda per bank.
Really that should cover almost anything you'd need.
If you see on the logging one bank is always different during say open loop, then via the cylinder trims you could adjust this prior to using closed loop
spitfire4v8 said:
I was expecting it to work like the mbe system .. one fuel map with one correction table per bank .. like the new emerald k6 update is also going to have.
But the correction table can only apply to the main fuel map.If it has some sort of table per bank, it would only be to allow you to trim those cylinders. Which via logging you could do anyway albeit manually.
Although TBH I'd far rather do it manually, as half the time automated correction tables....you'd be forever following them and changing things.
Once it is up and running and mapped, those tables should be redundant anyway
Hi Steve .. having two adaption tables is useful if you have airflow discrepencies bank to bank.
You can update the main fuel map based on the average of the two corrections being made at any one load site, then after that is done each adaption table is having to make the smallest trim required per load site to keep to the target afr.
Once the main fuel map is set as good as possible, any small airflow discrepencies between banks is catered for with a constantly updating adaption table per bank. You don't then have to burn any changes to the main map , just allow the two adaption tables to account for the small airlfow changes occuring across the two banks..
You're right in that , if everything is accurately machined and airflow increases with throttle opening evenly across the banks, you shouldn't need twin adaption tables, but in the real world there will be small airflow changes even between individual cylinders (difficult to adjust for unless I had 8 adaption tables) or more usually across the banks where the central linkage might throw in an error.
You can update the main fuel map based on the average of the two corrections being made at any one load site, then after that is done each adaption table is having to make the smallest trim required per load site to keep to the target afr.
Once the main fuel map is set as good as possible, any small airflow discrepencies between banks is catered for with a constantly updating adaption table per bank. You don't then have to burn any changes to the main map , just allow the two adaption tables to account for the small airlfow changes occuring across the two banks..
You're right in that , if everything is accurately machined and airflow increases with throttle opening evenly across the banks, you shouldn't need twin adaption tables, but in the real world there will be small airflow changes even between individual cylinders (difficult to adjust for unless I had 8 adaption tables) or more usually across the banks where the central linkage might throw in an error.
spitfire4v8 said:
Hi Steve .. having two adaption tables is useful if you have airflow discrepencies bank to bank.
You can update the main fuel map based on the average of the two corrections being made at any one load site, then after that is done each adaption table is having to make the smallest trim required per load site to keep to the target afr.
Once the main fuel map is set as good as possible, any small airflow discrepencies between banks is catered for with a constantly updating adaption table per bank. You don't then have to burn any changes to the main map , just allow the two adaption tables to account for the small airlfow changes occuring across the two banks..
You're right in that , if everything is accurately machined and airflow increases with throttle opening evenly across the banks, you shouldn't need twin adaption tables, but in the real world there will be small airflow changes even between individual cylinders (difficult to adjust for unless I had 8 adaption tables) or more usually across the banks where the central linkage might throw in an error.
That makes no sense though.You can update the main fuel map based on the average of the two corrections being made at any one load site, then after that is done each adaption table is having to make the smallest trim required per load site to keep to the target afr.
Once the main fuel map is set as good as possible, any small airflow discrepencies between banks is catered for with a constantly updating adaption table per bank. You don't then have to burn any changes to the main map , just allow the two adaption tables to account for the small airlfow changes occuring across the two banks..
You're right in that , if everything is accurately machined and airflow increases with throttle opening evenly across the banks, you shouldn't need twin adaption tables, but in the real world there will be small airflow changes even between individual cylinders (difficult to adjust for unless I had 8 adaption tables) or more usually across the banks where the central linkage might throw in an error.
If you update based on an average in the middle, then you'd potentially be trying to trim one bank one way, and the other bank the opposite way.
IMO you would always want closed loop either doing nothing, or pulling fuel. Not adding on one bank and pulling on the other.
And I presume the "adaptation table" you refer to is the CL correction table ? Or are you calling that the manual individual cylinder trim tables ? Two different things
And presumably you would have the linkage and each blade balanced as best as possible at idle, so that aspect should be almost identical the rest of the opening.
But you cant control port shapes, differences, cam/lifter/rocker gear variances, exhaust variances, injectors etc
You're wayyyy over thinking this IMO. Two CL correction tables make no sense when there is only a single main fuel map.
You have a single AFR target table, both banks will target this after the map has been tuned correctly. There should be minimal corrections occurring. It almost reads as if you want an AFR table per bank ?
You can view logging, which would be most sensible in open loop mode and see how each bank is running relative to each other. then adjust the individual cylinder trims as required.
Then CL should be doing almost no work on either bank with a good and proper map setup.
Edited by stevieturbo on Thursday 30th April 10:21
Yes by adaption table I mean a trimming table per bank which is read in real time to apply a correction over the top of the fuel map, per bank, to take into account differences in airflow through increasing throttle opening. It does happen no matter how accurately the linkages are machined / made. The s80 has one trimming table only, so if there is a consistent difference at say throttles 25percent through to 55 percent the adaption tables would reflect that and store trimmed fuel numbers to work from next time. As I said, MBE use this system and it works brilliantly.
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