Data Logs! Post them here.

[thambu19]

Originally Posted by jvincent

Going WOT in 3rd gear my load starts of at about 0.8 at 2800 RPM and gets up to 1.3 at around 7000 RPM.

Cruising at 3200 RPM in 6th it's around 0.5.

Thanks that looks more like what I would expect. I dont expect those number to change from stock numbers unless cam timing has been changed or someone is running a header to help breathe better (at the expense of emissions which I am guessing no body cares about in this forum)

[Kodename47]

Originally Posted by thambu19

I still do not understand the g/rev concept. Is it same as volumetric efficiency meaning 1.0 = 100% VE? If that is the case why do we have numbers like 1.4 and 1.5 since I dont expect an NA engine to run at 150% VE.

Simple, MAF scale is in g/s. Load is g/rev.

Here's the maths:
RPM/60=Rev/s
MAF(g/s)/(Rev/s) = g/rev

@solidONE which ROM are you running? Looking through some 2D tables I have found another that is similar to the A/F Learning ranges I posted above but the values are smaller. To test you can just set the last boundary just above the highest g/s you see in closed loop. That way you shouldn't get any LTFT in the majority of your open loop. You can try changing one at a time to see which one changes, it could be one for DI and one for PI, the 2nd one has lower values so is possibly setup to generate LTFT from different areas of load.

[thambu19]

Basically MAF (in g/s) / (Engine speed in rpm /60 to convert rpm to rpm /2 as there are one intake stroke every two revs * 2 litres of engine volume * 1.2 density of air) should give VE

So if MAF at 7500rpm = 150g/s then
VE = 150/(7500/60/2*2*1.2) = 1 assuming IAT = 25degC

[thambu19]

Originally Posted by Kodename47

Simple, MAF scale is in g/s. Load is g/rev.

Here's the maths:
RPM/60=Rev/s
MAF(g/s)/(Rev/s) = g/rev

I see so the load isnt necessarily VE then.

if MAF at 7500rpm = 150g/s then Load = 150 / (7500/60) = 1.2 g/rev

[thambu19]

Any one knows the AFR for best torque on this engine? Typically it is 12.5 to 12.25. Usually going richer doesn't yield better torque. Could be different on this due to higher compression and knock relief from enrichment

[solidONE]

Originally Posted by thambu19

Have you messed with the cam timings? If you are running too much overlap there is no point looking at AFRs in the scavenging range since the O2 sensor is easily confused with the fresh air that is short circuiting the engine.

That was what I was thinking as well considering that at the afr lean spike is right where the cam overlap increases, but I wanted to try to see if I could get the afr closer to 12.7:1 where it's been going as lean as 16.1:1 according to the stock O2 before moving on to cam timing adjustments.

Here's an earlier log I did while running E85 with the variable cam timing being logged. Any input would be appreciated, so I have a better idea how to proceed with the cam timing adjustments once I get there. Thanks! (dont mind the lean lump on the 91 octane pull, it was due to loading a load limit table that was not well suited to my setup. That lean lump has been address by increasing the load limit where it goes lean.)

http://datazap.me/u/solidone/plm3-ca...1698&mark=1572

Heres a graph to give you an idea what kind of power is being but down on 91 octane petrol versus E85 using the same cam timing tables, which in terms of midrange torque, I'm quite happy with. Though, I wouldn't mind some more top end, or more mid range for that matter. lol

Originally Posted by Kodename47

Simple, MAF scale is in g/s. Load is g/rev.

Here's the maths:
RPM/60=Rev/s
MAF(g/s)/(Rev/s) = g/rev

@solidONE which ROM are you running? Looking through some 2D tables I have found another that is similar to the A/F Learning ranges I posted above but the values are smaller. To test you can just set the last boundary just above the highest g/s you see in closed loop. That way you shouldn't get any LTFT in the majority of your open loop. You can try changing one at a time to see which one changes, it could be one for DI and one for PI, the 2nd one has lower values so is possibly setup to generate LTFT from different areas of load.

I have the A01C rom currently.

[thambu19]

Originally Posted by solidONE

That was what I was thinking as well considering that at the afr lean spike is right where the cam overlap increases, but I wanted to try to see if I could get the afr closer to 12.7:1 where it's been going as lean as 16.1:1 according to the stock O2 before moving on to cam timing adjustments.

Here's an earlier log I did while running E85 with the variable cam timing being logged. Any input would be appreciated, so I have a better idea how to proceed with the cam timing adjustments once I get there. Thanks! (dont mind the lean lump on the 91 octane pull, it was due to loading a load limit table that was not well suited to my setup. That lean lump has been address by increasing the load limit where it goes lean.)

http://datazap.me/u/solidone/plm3-ca...1698&mark=1572

Heres a graph to give you an idea what kind of power is being but down on 91 octane petrol versus E85 using the same cam timing tables, which in terms of midrange torque, I'm quite happy with. Though, I wouldn't mind some more top end, or more mid range for that matter. lol




I have the A01C rom currently.

If you know that you are scavenging a ton then trying to get to an AFR = 12.7 at those points will not be a good idea because you could be running much rich inside the cylinder (trapped volume)

Ultimately what matters the most for torque is to have an incylinder AFR = 12.5 or 12.25.

Another thing to consider when changing cam timings is that if you change the cam timing in regions meant to run closed loop it will mess up the STFT and eventually LTFT in the region. This will make engine think it is getting way more Airflow than it is getting and hence will ask for more fuel than necessary and also will be running off a different spark lookup (usually more retarded) and hence you can feel a dead spot in power delivery when you hit there.

Id say keep cam timings normal in closed loop region and just mess with the WOT cam timings if need be. Scavenging is great for torque but beyond a point what happens is the scavenged rpms torque increase will make the dip (non scavenged region between scavenged region and normal power band) look much bigger. Most OEMs who have a scavenged exhaust do some torque shaping to reduce the size of this torque dip. It is in inevitable to some extent unless one has unequal headers designed so that one bank scavenging at one rpm and the other at another rpm sort of smoothing out the torque shape and expect the power band to kick in just as the scavenging falls off.

Another approach is to altogether move the scavenging to a higher engine speed so that the scavenging drops off just where the powerband is picking up. But this will lead to a drop in torque at the low 2K rpms and most OEMS want the torque there for Fuel Economy reasons since it is where a car runs most time in an FTP cycle for fuel economy test.

[thambu19]

You can expect to get 5-10% better VE with heavy scavenging at the most from what OEMs already have calibrated to. So seeing super high AFRs means its not real. On E85 you dont have to scavenge a ton because engine isnt knock limited on E85. Half the benefit of scavenging is VE improvement and other half is knock relief which you dont get on E85 since it is already knock free

[solidONE]

Originally Posted by thambu19

You can expect to get 5-10% better VE with heavy scavenging at the most from what OEMs already have calibrated to. So seeing super high AFRs means its not real. On E85 you dont have to scavenge a ton because engine isnt knock limited on E85. Half the benefit of scavenging is VE improvement and other half is knock relief which you dont get on E85 since it is already knock free

Got ya! In CL operation while running 91 petrol it's been pretty solid (much less aggressive overlap) aside from your typical tip-in and medium load knock correction in the 2600~3200rpm range. It's actually quite annoying since that where you spend the most time putting around town, but it seems no amount of enrichment or timing retard can get rid of it completely. So, most of us just let the ecu do it's thing and dial back the IAM now and again. I seriously wonder if it's real knock that the knock sensor is picking up, or some sort of "phantom knock."

Since you say the E85 doesn't require as much scavenging, how would you adjust the cam timings according to the earlier log I posted? Slower ramp up to the overlap at WOT?

You probably wont get the reference but...

[thambu19]

Originally Posted by solidONE

Got ya! In CL operation while running 91 petrol it's been pretty solid (much less aggressive overlap) aside from your typical tip-in and medium load knock correction in the 2600~3200rpm range. It's actually quite annoying since that where you spend the most time putting around town, but it seems no amount of enrichment or timing retard can get rid of it completely. So, most of us just let the ecu do it's thing and dial back the IAM now and again. I seriously wonder if it's real knock that the knock sensor is picking up, or some sort of "phantom knock."

Since you say the E85 doesn't require as much scavenging, how would you adjust the cam timings according to the earlier log I posted? Slower ramp up to the overlap at WOT?

You probably wont get the reference but...

I had a posting in the knock and pre-ignition thread regarding tip-in knock
Here it is: http://www.ft86club.com/forums/showp...95&postcount=7

One should never pull base timing to avoid tip in knock.

If drivability is what you want you may want to read this posting:http://www.ft86club.com/forums/showp...7&postcount=53

You can drop the cam overlap for E85 compared to your 91 octane tune.

Havent had a chance to go through the log yet. I will.

[thambu19]

One thing to always remember though is that Cams and spark go together. So if you make a cam change most likely it also needs a spark adjustment. This adjustment can also be pulling out spark.

[thambu19]

@solidONE
Looks like you have kept intake at max phase all the way to 6K rpm. Let me put it this way. Usually OEMs wont leave anything on the table unless they will get hit by emissions at WOT. So that means the only area they would have compromised torque will be in the scavenging region before the dip. After the dip the Intake cams are chosen that gives best possible VE/Torque. So by moving the cams so far I am not sure if you are gaining anything.
There is only one way to tell though and that is a vehicle dyno. Unfortunately that is not practical. Fortunately there is another and that is the MAF sensor. If you compare back to back logs (dont use just one run per setup. Use two to make sure it is repeatable) of MAF you can tell if you are gaining or losing in air flow. Stop advancing/retarding cams once there is no more gain in airflow.
The tricky part is sometimes Intake and Exhaust timings have to go together.

[solidONE]

Originally Posted by thambu19

I had a posting in the knock and pre-ignition thread regarding tip-in knock
Here it is: http://www.ft86club.com/forums/showp...95&postcount=7

One should never pull base timing to avoid tip in knock.

If drivability is what you want you may want to read this posting:http://www.ft86club.com/forums/showp...7&postcount=53

You can drop the cam overlap for E85 compared to your 91 octane tune.

Havent had a chance to go through the log yet. I will.

Retarding the base timing was done to address the medium load/low rpm knock. For tip in I have increased the amount of transient enrichment and transient ignition retard on each corresponding table that have been defined thanks to our resident programmers hacking the factory ecu.

Edit: in the other thread about knock, you stated to leave certain cal tables alone. If you currently own this car, I invite you to log the stock calibration using 91 octane or even 93 octane, if that's what you have available in your state, for knock. Then reflash with a OTS tune from Vishnu or I can send you one of my cals I tuned for 91 octane and I believe you will see why we've been making modifications to the stock tables for better knock resistance, power, and economy. Since most of us have no means to measure emissions, I cannot say whether its worsened or improve with the modifications.

Originally Posted by thambu19

@solidONE
Looks like you have kept intake at max phase all the way to 6K rpm. Let me put it this way. Usually OEMs wont leave anything on the table unless they will get hit by emissions at WOT. So that means the only area they would have compromised torque will be in the scavenging region before the dip. After the dip the Intake cams are chosen that gives best possible VE/Torque. So by moving the cams so far I am not sure if you are gaining anything.
There is only one way to tell though and that is a vehicle dyno. Unfortunately that is not practical. Fortunately there is another and that is the MAF sensor. If you compare back to back logs (dont use just one run per setup. Use two to make sure it is repeatable) of MAF you can tell if you are gaining or losing in air flow. Stop advancing/retarding cams once there is no more gain in airflow.
The tricky part is sometimes Intake and Exhaust timings have to go together.

The cam table I've loaded were supposedly dialed by other members on this forum to work with the long tube headers I've installed. Now, I'm assuming that since the length of the runners are much longer also the lack of a catalytic converter on the header I'm currently running compared to the stock header it will require much different cam phasing to extract the maximum amount of power while WOT. The amount of power I've gotten while using these cam tables and this long tube header over a short tube, cat-less equal length header I was running previously was very satisfactory, to say the least. I'm sure even more power can be extracted with some tuning, but I'm happy using it as baseline.


Blue, long tube EL header (current)
Red, short tube El header
baseline stock header with tune was about 168whp and 135tq
This is on 91 octane petrol:


Using the logs I can replicate closely what it will read on a dyno using a freeware called virtual dyno, so measuring power output after changes is not a problem. I've used this software extensively and have found that it can produce very repeatable and consistent dynographs as long as the road is perfectly flat and there is no wheel slip in the log along with accurate input of vehicle weight, wheel diameters, temp and barometric pressure. Check it out if you haven't seen it before. http://www.virtualdyno.net/

[Kodename47]

@SoldONE is it an OFT A01C? I'll dig out the table address for you to try If you want.

Other things to note, overlap will cause changes in AFR however it is unlikely that the cylinder AFR will be that different. By that I mean cylinder AFR of <13 and O2 AFR of 15. I know what you're trying to do, but if you're going to play with the AVCS then I'd do that 1st before fueling otherwise you'll just have to do it all again.

I have something in the pipeline with regards to road tuning AVCS....
@thambu19 most tunes only change the cam timings under WOT. Why don't you start liking at the tunes