First logs..Not sure if they are good or bad

[Ridgeracer]

I have 816cc modded stock injectors. I'm in NYC so I guess close to 14.7

[Ridgeracer]

Thinking about switching to EWG but I got to save for this. Car seems fast as is. I would just be happy with a safe, consistent tune. I'll take your advice and work on getting a WB and new DP for it first.

[mickeyd2005]

Assuming you don't have a massive boost leak and that the logs were done at Patm = 14.7, then your MAF scale is approximately 27% off. Multiply your MAF and load by 1.27 to get a more accurate MAF and load value. I don't think you have a boost leak because your car is accelerating correctly based upon your "adjusted" MAF.

 

In order to make your fueling work, it looks like the injectors may have been scaled to 650 cc/min.

 

After discussing modified injectors with some of the STi guys, I think I know where the problem is. Modified injectors DO NOT have stock latencies even though there is a HUGE myth that they do have stock latencies. The only way to make the injectors idle properly with stock latencies is to either change the injector scalar or screw around with the MAF. I know that some of the STi guys scale their modified injectors at 650 cc/min and use stock latencies.

 

The problem with using MAF or scalar to adjust for incorrect latency is that it won't work at low load and high rpm.

 

In the low load and low rpm range, the ecu is in closed loop so any errors in fueling will be adjusted by the ecu.

 

Above 4000 rpm, the ecu is almost always in open loop so your fueling must be correct.

 

At 4000-4800 rpm and load between 0.6 and 0.85 g/rev, a latency that is too low will cause the fueling to run too lean. I think that's why you are getting -7 FLKC in this range.

 

Try logging battery voltage and latency.

[Infamous1]

It is a shame some "professional" tuners don't know what this ^^^ man knows.

[Tuning Alliance]

Are these logs done with the modified waste-gate flapper arm?

[mickeyd2005]

There is no doubt that OP will eventually make more power when his boost control issues are resolved.

 

However, his current problem is the partial throttle knocking and that has nothing to do with the wastegate. The WOT logs actually don't have any knocking in them. The FLKC is driving down the timing. There's no way to know where the FLKC is causing the knock without resetting the ecu and doing partial throttle logs.

 

The large AFR learning values indicates a poorly scaled MAF. That combined with the calculations of MAF based upon MAP indicates that his MAF and fueling issues need to be resolved first. I normally allow AFR learning C to vary by +-3 and AFR Learning D +-2.

 

It's common to have some negative FLKC. However, -7 and -2.8 degrees is too much and FLKC in the high load range is not good. It causes driveability issues.

[Tuning Alliance]

His waste-gate flapper was actually not sealing at all. This means increased airflow across the board, and requiring recalibration of the maf. You can harp on the tune all day long, but he made physical changes to the setup, since the tune.

[Infamous1]

His waste-gate flapper was actually not sealing at all. This means increased airflow across the board, and requiring recalibration of the maf. You can harp on the tune all day long, but he made physical changes to the setup, since the tune.

This is simply not true, it wouldn't effect the MAF scaling....

 

[Tuning Alliance]

Ok first of all. The ECU was not reset and had learned -3% fueling into top end. So its already 3% leaner then how it was tuned. So Ian (reset the ecu) then resend your map, then get a more useful log.

 

Secondly, you don't think changing the waste-gate, or turbo will effect your maf scale? A customer just switched from a .82 hotside to a 1.06 hotside and the car was now fueling almost a full point off. This is on a 3" blow-thru maf in which i didn't believe the scaling would be altered so greatly, but it was...

 

Air flow through the engine as a system, and how the engine will effectively use the air and fuel is a large factor. Idling with a vf40 and with a gt30r are different, the car is seeing much cooler dense air, even if its pulling the exact same voltage at the maf.

 

With the wastegate leaking at idle the turbos efficency, drops and produces less and warmer air into the manifold, requiring less fuel. Now with it sealed its flowing better and denser air, needing more fuel.

[mickeyd2005]

His waste-gate flapper was actually not sealing at all. This means increased airflow across the board, and requiring recalibration of the maf. You can harp on the tune all day long, but he made physical changes to the setup, since the tune.

 

This is absolutely not true. This is a MAF based car.

 

Opening and closing the wastegate doesn't change the MAF scaling.

 

Did you tune this car?

[mickeyd2005]

Ok first of all. The ECU was not reset and had learned -3% fueling into top end. So its already 3% leaner then how it was tuned. So Ian (reset the ecu) then resend your map, then get a more useful log.

 

Secondly, you don't think changing the waste-gate, or turbo will effect your maf scale? A customer just switched from a .82 hotside to a 1.06 hotside and the car was now fueling almost a full point off. This is on a 3" blow-thru maf in which i didn't believe the scaling would be altered so greatly, but it was...

 

Air flow through the engine as a system, and how the engine will effectively use the air and fuel is a large factor. Idling with a vf40 and with a gt30r are different, the car is seeing much cooler dense air, even if its pulling the exact same voltage at the maf.

 

With the wastegate leaking at idle the turbos efficency, drops and produces less and warmer air into the manifold, requiring less fuel. Now with it sealed its flowing better and denser air, needing more fuel.

 

You're saying that at idle the MAF intake will be affected by the turbo?

 

OP doesn't have a blowthrough. There's no way a turbo affects a MAF intake scale below 100 g/s. The turbo has no impact on the intake temperature on a standard MAF setup.

 

And we're not talking 5% or 10% here. We're talking 27% off.

[Tuning Alliance]

The maf scaling won't change dramatically, it may only be slight! More the fact that the car is hitting different maf voltages then it was previously.

 

I'm not going to waste time fighting about it, I tuned this car and plenty others. The learned -3% throughout the pull should have been a red flag to anyone.

[Tuning Alliance]

OP doesn't have a blowthrough. There's no way a turbo affects a MAF intake scale below 100 g/s. The turbo has no impact on the intake temperature on a standard MAF setup.

 

The turbo has a huge effect, but the car doesn't see it. It measures the air coming in, and temp coming in. What happens after it goes through the turbo? It gets compressed and compression causes an increase in temp (pressure, volume, temp laws) which the car is not measuring! However, in a blow-thru setup it will measure the air as it comes into the engine.

[mickeyd2005]

The turbo has a huge effect, but the car doesn't see it. It measures the air coming in, and temp coming in. What happens after it goes through the turbo? It gets compressed and compression causes an increase in temp (pressure, volume, temp laws) which the car is not measuring! However, in a blow-thru setup it will measure the air as it comes into the engine.

 

Have you tuned many rotated setups?

 

We're not talking rotated setup with speed density or blow through setups. We're talking about a MAF sensor installed BEFORE the turbo.

 

The MAF scaling between 20 and 100 g/s is not affected by the turbo. And yes, I have seen the effect of installing a new larger turbo. MAF scaling is almost unchanged.

 

If you tuned this setup, why don't you tell us what the injector scaling and latency you used? OP can datalog it anyway.

[Infamous1]

The turbo has a huge effect, but the car doesn't see it. It measures the air coming in, and temp coming in. What happens after it goes through the turbo? It gets compressed and compression causes an increase in temp (pressure, volume, temp laws) which the car is not measuring! However, in a blow-thru setup it will measure the air as it comes into the engine.

You do realize you are talking about two different setups? In the OP case a faulty WG will NOT effect the way the MAF should be scaled. The -3 learning is quite obvious however it will not hide the fact that the MAF is WAY off. Just look at the MAF volt's vs g/s. WAY OFF, a blow through MAF has nothing to do with the OP car at all.

[Tuning Alliance]

The g/s vs volts is different the stock YES. Of course the car has a different intake, larger injectors, FMIC, and a bigger turbo. There are many ways to scale the injectors, change latency, injector trim error. Your right I don't use 816cc for a 816cc injector.

 

The fueling is flat and not that far off.

[mickeyd2005]

It's true that you can use whatever injector scalar you want. As long as the MAF scale goes with it.

 

However, you can't arbitrarily choose a latency. There can only be one latency unless you have a 3D MAF scale or the car was tuned using speed density which is an equivalent 3D scale. This would explain the -7 FLKC at 4000+ rpm in the low load range.

 

I think the scalar is 650.

 

On a bone stock ecu, load can be approximated as:

 

load = 0.090553*MAP - 0.0834

 

I got those numbers from the 522N rom.

 

On a stage two car, the slope will increase from 0.090553 to 0.092 to 0.098. On a stage 3 car with a larger turbo, it might go up to 0.105. I have found this relationship to be very accurate between 2000 and 4000 rpm on any LGT.

 

OP is running 2.23 g/rev at 3356 rpm and 30.23 psi MAP. That indicates to me that the MAF is way off true. The AFR learning C and D indicates it isn't accurate even for the injector scalar. And I stand by my statement that AFR learning C and D are not affected by the wastegate opening or closing.

[rc0032]

Is Tuning Alliance Jon? or is that HBsomethingsomethingsomething?

[mickeyd2005]

I think he is TDC Mike.

[Ridgeracer]

Well the first set of logs were taken after I resent the realtime map to the ECU. The most recent logs where done with less than 40 miles of driving since the map was resent to the ECU.

[edmundu]

Well the first set of logs were taken after I resent the realtime map to the ECU. The most recent logs where done with less than 40 miles of driving since the map was resent to the ECU.

 

IF by resent, you mean just that...resent. Then this does nothing for resetting the stored learned values. You have to reset or clear the RAM for learning to be back at 0.

[edmundu]

....

On a bone stock ecu, load can be approximated as:

 

load = 0.090553*MAP - 0.0834

 

I got those numbers from the 522N rom.

 

On a stage two car, the slope will increase from 0.090553 to 0.092 to 0.098. On a stage 3 car with a larger turbo, it might go up to 0.105. I have found this relationship to be very accurate between 2000 and 4000 rpm on any LGT.

 

 

Is this formula only accurate for the mentioned rpm area? Reason I ask is I tried applying it in higher rpm areas, and it was not jiving with my logs....but it did follow in the peak trq area. Which on my setup is around 4800 rpm in 3rd gear.

[edmundu]

As a point of reference, I run an AVO intake & dw740's...My intake scaling is also much higher than the OP's....although I use 725cc for scaling in Enginuity, 3654 in ST speak...

 

In the same 4.66-4.7v maf levels I see 299-306 g/sec, and don't hit 320 until 4.78v.

[Tuning Alliance]

The learning was 2.2, 5, -8.3, -3 trims are not that far off, considering its a 0-25. The -8.3 and -3 clearly caused all the learned knock corrections. Any car will become unhappy when it learns negative fueling up top, and reduce timing.

[mickeyd2005]

Is this formula only accurate for the mentioned rpm area? Reason I ask is I tried applying it in higher rpm areas, and it was not jiving with my logs....but it did follow in the peak trq area. Which on my setup is around 4800 rpm in 3rd gear.

 

It is only accurate before peak torque at WOT and at partial throttle.

 

It is not accurate at idle nor is it accurate at very low throttle.

 

That's the equation that the ecu uses to estimate load when the MAF fails. It's the primitive speed density mode.

 

load = k x MAP + offset

 

k and offset are constantly evaluated. If the MAF fails, it uses either the default rom setting (the number that I posted) or the latest k and offset that it calculated based upon previous driving since ecu reset.

 

On a modified LGT, k should NEVER be below 0.9. That's worse than stock. It's only possible if the injector scalar and MAF were arbitrarily scaled down. However, this would cause an incorrect load calculation and unless the timing table was rescaled, it would result in an incorrectly high timing in the partial throttle area.