Tuning a FP Green w/ AFC

[allturbo]

I'm considering getting a Green for my next mod and was wondering if anyone had experience tuning one with an AFC. Right now my settings are -35% on the high tables. This is tuned for 1800hz worth of airflow, which means the ecu is only seeing 1170hz. Not sure was kind of hz a Green in capable of pulling in street trim, but I'm sure it's over 2000. Just as an example, let's say it hits 2300hz. To match the increase in air, I have to richen the AFC to -30. That means the ecu will be seeing 1610hz. Since 2g ecu's are timing senstive to increases in airflow, this is not good. I generally want the hz count that the ecu is seeing to be under 1500.

Can anyone with a big turbo and AFC share their experiences? I know I can get a AFPR, increase base fuel pressure, and lean out the AFC a bit. I can also increase base timing w/ my 1gCAS to counter the timing being pulled from the ecu. This will give me a little more room to play, but are the limitations of 2g AFC tuning too much that DSMlink/standalone is needed? Any thoughts on this would be great.

 

[ProjectGSX]

I run a Big 28 and an AFC and cant get it tuned perfectly. If you are going big, you should do it right. DSMLink or AEM.

 

[jw]

Too low of aircount is not always a good thing. When the aircount get too low, the ECU advance too much timing and it become more prone to knocks.

When my old turbo failed on me, I was only getting around 1200hz. Even at WOT, the ECU gave timing like I was doing part throttle with 30+ degree timing. Knocks were sky rocket and the car ran like crap even it had a lot of timing.

 

[larryd]

Originally posted by ProjectGSX
I run a Big 28 and an AFC and cant get it tuned perfectly. If you are going big, you should do it right. DSMLink or AEM.

not always the situation.. dave (GSX4LIFE) seems to be plenty happy with his S-AFC and his L2R.. though Im sure the DSMlink wouldnt hurt, its not always necesary

 

[TSi92]

Originally posted by ProjectGSX
I run a Big 28 and an AFC and cant get it tuned perfectly. If you are going big, you should do it right. DSMLink or AEM.

AFC is a good tuning tool. Lots and lots of DSM's running very fast with them, big or small turbos. If you can't tune an AFC you should stay away from the dsmlink or standalone systems.

 

[Tranman]

I'm currently trying to get my Green/660cc/HKS camshafts tuned with my SAFC. Have a unhacked MAF, and at 18psi it hits nearly 2400Hz (its VERY cold out here in Ohio). I currently have my Hi maps between -40 to -32 or so. But of course, people's car with be different and locations are different. In slightly warmer weather, I have to lean out the airflow some more.

But I definitely need a datalogger rather than seat of the pants to do better tuning.

 

[allturbo]

I'm pretty comfortable tuning w/ an afc. My last time at the track I ran 107mph traps at 17psi (small 16g). I logged the run and the timing was 21deg at the top of third. It felt pretty good to say the least. Now that I have cams and BS removed I'm sure it'll we better than that.

Too low of aircount is not always a good thing. When the aircount get too low, the ECU advance too much timing and it become more prone to knocks.

I'm not familiar with 1g ecu's, but a 2g ecu will start to pull timing do to high airflow counts regardless of knock. Since a Green flows upwards of 2400hz, with my setup the ecu will see something north of 1600hz. Anyways, I'll probably end up going dsmlink or aem once I get tired of the limitaions of afc tuning. I was just curious on people's thoughts of big turbo afc tuning. Oh and Tranman, whenever you get that thing loggged it would be great if you could post the results on this thread. I'm really curious to see what the ecu is doing with timing since you're flowing so much air.

 

[ItsStockOfficer]

Originally posted by allturbo
I'm considering getting a Green for my next mod and was wondering if anyone had experience tuning one with an AFC. Right now my settings are -35% on the high tables. This is tuned for 1800hz worth of airflow, which means the ecu is only seeing 1170hz. Not sure was kind of hz a Green in capable of pulling in street trim, but I'm sure it's over 2000. Just as an example, let's say it hits 2300hz. To match the increase in air, I have to richen the AFC to -30. That means the ecu will be seeing 1610hz. Since 2g ecu's are timing senstive to increases in airflow, this is not good. I generally want the hz count that the ecu is seeing to be under 1500.

Can anyone with a big turbo and AFC share their experiences? I know I can get a AFPR, increase base fuel pressure, and lean out the AFC a bit. I can also increase base timing w/ my 1gCAS to counter the timing being pulled from the ecu. This will give me a little more room to play, but are the limitations of 2g AFC tuning too much that DSMlink/standalone is needed? Any thoughts on this would be great.

You'll be at 2200 htx, maybe 2400 with cams...and you'll be able to tune it fairly well. Dont worry about it, you can upgrade later.

Sean

 

[GSX4LIFE]

None of this is very relavent. The Hz you see on the SAFC,is not an actual count, rather a guestimate of what is actually going on. Case in point: I have seen 2300Hz at 20psi, and at 26psi. I have seen about 2100Hz at 19psi and at 22psi. This was a repetable thing. Temps were similar throughout the differences. Ive also seen this on the same day back to back runs at up to 5psi difference, and logged the same Hz count. You really can tune by Hz. There is only one true way of tuning in my oppinion. Wideband baby I do like my SAFC very much wiht the L2R. Its tuned great. It seems, though, that its weekness is the 2G ecu. I am tuned about perfect at 20psi on pump gas. But, with race ga s, no matter how much boost I am running, Im unable to really lean it out good enough. The ecu just keeps dumping fuel. But I get no knock and pretty good timing(about 21 degs). So I really cant complaine.

 

[jw]

When you talk hz count, you have to consider rpm. Running 22psi at 5500rpm may yield 2100hz while 22psi at 7krpm may yield 2300hz. The higher you rev, the more air is needed to maintain the pressure so it should be no surprise here.

1G or 2G ECU works the same. More airflow means you have less aggressive timing map. It's not airflow alone but air mass (contributed by airflow, temperature and baro pressure). Therefore running larger injectors and leaning it out usually yield a few degree more timing (if there is no knocks and everything else remain the same).

 

[allturbo]

More airflow means you have less aggressive timing map.

This is what I'm taking about. Of course wideband is the best way to tune, but running a large turbo using stock ecu and afc will have it's limitaions. According to Tranman his aircount is at around 2400hz. This is a lot more airflow than the stock ecu is meant to see. I have 660's so I can lean out the afc to a decent amount, but I was thinking that it may not be enough. Since GSX4LIFE has been able to get 21 deg of timing, maybe it won't be that bad. I just keep thinking about how my tuning went when I 1st got a 16g. At the beginning I started at 10psi and moved my way up. This was on stock fuel except for a fuel pump. Anyway, my datalogs showed timing decrease as I raised boost pressure. I even tried 100oct gas to eliminate the factor of knock retard due to bad gas. Eventually I went 660's w/ afc and solved my timing advance problems. My point is that it would seem that going with a large turbo would create the same problems, ie too high of an airflow count.

Anyways, if it works for GSX4LIFE maybe it'll work for me. My ecu seems to be pickier than others, but I guess I'll find out when I upgrade.

Oh and one last thing. On the statement of "None of this is very relavent. The Hz you see on the SAFC,is not an actual count, rather a guestimate of what is actually going on." Isn't the hz count the actual amount of air the MAS is seeing (ie. karman vorticies or whatever). The AFC is tapped into that wire at the ecu so it can intercept it and change that amount. Since the ecu advances timing using several factors such as knock and aircount, I would think that Hz would be pretty important. Anyone correct me if I got this wrong.

 

[cagri]

Originally posted by Tranman
I'm currently trying to get my Green/660cc/HKS camshafts tuned with my SAFC. Have a unhacked MAF, and at 18psi it hits nearly 2400Hz (its VERY cold out here in Ohio). I currently have my Hi maps between -40 to -32 or so. But of course, people's car with be different and locations are different. In slightly warmer weather, I have to lean out the airflow some more.

But I definitely need a datalogger rather than seat of the pants to do better tuning.

Ok I am a little confused I thought I tuned my car pretty good. I have Big28 with all supporting mods except FMIC. I have 650cc injectors, and my hi settings are between -30 to -25. ??? You have a much larger turbo plus cams but you are much leaner than I am? Does that mean I am way too rich? Or You are way too lean? I know every car is different but that is a lot of difference. When I try to lean mine out temps start climbing and my timing drops on my datalogger so I know I am not that far off.

 

[ProjectGSX]

Originally posted by TSi92
AFC is a good tuning tool. Lots and lots of DSM's running very fast with them, big or small turbos. If you can't tune an AFC you should stay away from the dsmlink or standalone systems.

That is a very misleading statement.

My point was that at a certain power level it is beneficial to have a more flexible tuning tool.

Just because you can run fast with an AFC does not mean it is the perfect tool for the job. You could be running faster and safer with a better tool.

You go slice your bread with a chainsaw, I'll use a tool more suited for the job.

 

[ProjectGSX]

Originally posted by larryd
not always the situation.. dave (GSX4LIFE) seems to be plenty happy with his S-AFC and his L2R.. though Im sure the DSMlink wouldnt hurt, its not always necesary

That goes for you too.

Sure, its not necessary. You can run a 16g with no fuel upgrades either. If you want to get all of the safe power out of the turbo, you should upgrade the fuel system. Fuel control is the same thing. Sure, an AFC can do the job, but not as well as DSMlink can.

It is my opinion, and obviously not yours, that if you are going to go with a larger turbo (read, say, 400 crank HP+) that you should have a proper fuel tuning device and you better be able to see knock counts.

 

[TSi92]

Originally posted by allturbo


This is what I'm taking about. Of course wideband is the best way to tune, but running a large turbo using stock ecu and afc will have it's limitaions. According to Tranman his aircount is at around 2400hz. This is a lot more airflow than the stock ecu is meant to see. I have 660's so I can lean out the afc to a decent amount, but I was thinking that it may not be enough. Since GSX4LIFE has been able to get 21 deg of timing, maybe it won't be that bad. I just keep thinking about how my tuning went when I 1st got a 16g. At the beginning I started at 10psi and moved my way up. This was on stock fuel except for a fuel pump. Anyway, my datalogs showed timing decrease as I raised boost pressure. I even tried 100oct gas to eliminate the factor of knock retard due to bad gas. Eventually I went 660's w/ afc and solved my timing advance problems. My point is that it would seem that going with a large turbo would create the same problems, ie too high of an airflow count.

Anyways, if it works for GSX4LIFE maybe it'll work for me. My ecu seems to be pickier than others, but I guess I'll find out when I upgrade.

Oh and one last thing. On the statement of "None of this is very relavent. The Hz you see on the SAFC,is not an actual count, rather a guestimate of what is actually going on." Isn't the hz count the actual amount of air the MAS is seeing (ie. karman vorticies or whatever). The AFC is tapped into that wire at the ecu so it can intercept it and change that amount. Since the ecu advances timing using several factors such as knock and aircount, I would think that Hz would be pretty important. Anyone correct me if I got this wrong.

That's why you would want bigger than necessary injectors. You lean the hell out of the AFC and the ECU will think there's almost no airflow thus giving very agressive timing maps.

 

[BatmanGSX]

Originally posted by GSX4LIFE
None of this is very relavent. The Hz you see on the SAFC,is not an actual count, rather a guestimate of what is actually going on.

That is totally, 100% wrong. The count on the AFC is the actual count. Boost does not = airflow You getting the same count at higher boost just means turning up the boost didn't give you any more power. Airflow is indicative of power, not boost. Look at any compressor map, at a given pressure ratio (ie boost level) there is a range of airflow that the turbo will flow. If you are getting the same Karman count at higher boost it just means you didn't increase the airflow of the engine. This mean anything from crappy tuning to an intake or intake cam limitation.

 

[GSX4LIFE]

Originally posted by BatmanGSX


That is totally, 100% wrong. The count on the AFC is the actual count. Boost does not = airflow You getting the same count at higher boost just means turning up the boost didn't give you any more power. Airflow is indicative of power, not boost. Look at any compressor map, at a given pressure ratio (ie boost level) there is a range of airflow that the turbo will flow. If you are getting the same Karman count at higher boost it just means you didn't increase the airflow of the engine. This mean anything from crappy tuning to an intake or intake cam limitation.

Yeah. Im not making any more power with higher boost I gained 25 WHEEL HORSE POWER froma 1psi increase on the dyno. With no other changes to my settings. When you are even close to the power that I am, you can talk about me not making power. But since I am destroying your Green in power, dont make silly comments. Now, like i said, it is not exact. Let me further explaine why you cannot tune by Hz readings. (I guess I should have explained it further, since you cant understand it) Hz is measured at the MAF. From there the air is compressed, heated, slowed down, then cooled. Since there is much more to making power than simple quantity of airflow, how can one tune by it alone? And I know you dont rely on tuning this way alone, but you really should not be so quick to disagree with me until you think about it. Man you really dont deserve the wiseman title. I have also seen finding it amusing how you have gotten some threads closed because of being an Azzhole.

 

[ItsStockOfficer]

Originally posted by BatmanGSX


That is totally, 100% wrong. The count on the AFC is the actual count. Boost does not = airflow You getting the same count at higher boost just means turning up the boost didn't give you any more power. Airflow is indicative of power, not boost. Look at any compressor map, at a given pressure ratio (ie boost level) there is a range of airflow that the turbo will flow. If you are getting the same Karman count at higher boost it just means you didn't increase the airflow of the engine. This mean anything from crappy tuning to an intake or intake cam limitation.

Karman HTZ is a measure of air velocity, not air qauntity. The difference in velocity is not linear to the difference in qauntity. Consider the implications of this. GSX4LIFE, read his posyt slightly more carefully. If you turn up the boost and at the same temp at the same barometric pressure etc etc and get the EXACT same amount of karmans...On the EXACT same setup...your not going to make more power, since you will be having the same amount of air...however, since this is impossible, it dosen't matter a damn bit noe does it? Unless the setup is changed, it will take a higher air velocity to maintain a higher boost.

Just remember Karman are not linearly increased in regards to airflow. Going from 22 to 25 psi might onyl go from 2350 to 2450 karmans but your going to get a #### load of power if you can handle the air. Going from 15 to 18 might take you from 1600 to 1900, a much largher jump in air velocity, but not in air qauntity.