[OpenFlash]

Hi guys,
Last week, a few forum members had a dyno day in Las Vegas. Among the cars were 3 n54s. All 3 were FBO (or close to it). I was not present but I did ask to have all the dyno data sent to me so I could make this interesting same dyno/same day comparison. This isn't a hp comparison as the Procede car was running meth. But it does present a good opportunity to compare AFR targets. The Procede car (and perhaps the Cobb one as well?) were running stock secondary cats so AFR readings will read slightly leaner than actual. The Jb4 car was running completely catless so there should be no catalyst induced misreading. All 4th gear runs. AFR was measured at the tailpipe with fresh Dynojet AFR sensor.



Car 1
335
Procede Rev2.5
11-1 Stg 3
PWM Meth kit
FBO w/stock exhaust

Car 2
335
Cobb AP
Stg 2 map
100oct
FBO w/stock exhaust

Car 3
135
BMS JB4
Map 7
FBO
100oct

[frank35]

I saw the option of playing the fuel and boost the JB4 map6 of that new fuel values ​​you have changed?

[Jeff@TopGearSolutions]

People that have a Cobb must be rich

[vase330]

Originally Posted by Jeff@topgearsolutions

People that have a Cobb must be rich

?? Missed that part of the joke. Why do you say this?

[FirstBMWLA]

Originally Posted by vase330

?? Missed that part of the joke. Why do you say this?

Cause it's running rich burning more fuel more $$ I would guess

I see this becoming flame thread of the week. We're due for another I guess...

[OpenFlash]

Originally Posted by FirstBMWLA

Cause it's running rich burning more fuel more $$ I would guess

I see this becoming flame thread of the week. We're due for another I guess...

There is absolutely no reason for this thread to turn into a flame war. In fact, the owners of the cars are more than welcome to add whatever info they think is relevant to this thread (specific mods, car details, etc,.). Tuners are welcome to participate as well.

Shiv

[Glowin]

Originally Posted by shiv@vishnu

Hi guys,
Last week, a few forum members had a dyno day in Las Vegas. Among the cars were 3 n54s. All 3 were FBO (or close to it). I was not present but I did ask to have all the dyno data sent to me so I could make this interesting same dyno/same day comparison. This isn't a hp comparison as the Procede car was running meth. But it does present a good opportunity to compare AFR targets. The Procede car (and perhaps the Cobb one as well?) were running stock secondary cats so AFR readings will read slightly leaner than actual. The Jb4 car was running completely catless so there should be no catalyst induced misreading. All 4th gear runs. AFR was measured at the tailpipe with fresh Dynojet AFR sensor.

Car 1
335
Procede Rev2.5
11-1 Stg 3
PWM Meth kit
FBO w/stock exhaust

Car 2
335
Cobb AP
Stg 2 map
100oct
FBO w/stock exhaust

Car 3
135
BMS JB4
Map 7
FBO
100oct

And? I don't understand the point of the thread. Are we supposed to draw some conclusion?

As I read in a book, "Without analysis, raw data are left open to uninformed interpretation."

[ExpensiveTaste]

Too many factors for this thread to mean anything at all. Get a wideband sensor bung welded into the exhaust where there is still heat, test the same model car, with same mods (other than tune), with same conditions, and then it might be of some use at all...

[thebigragu99]

Originally Posted by FirstBMWLA

Cause it's running rich burning more fuel more $$ I would guess

I see this becoming flame thread of the week. We're due for another I guess...

No,it means that the arfs are richer..

Shiv the comparison is not completey fair,they not all the same fuels.

[Joshboody]

Fuel type won't make a difference as far as i know.

Any datalogs to match up?

[OpenFlash]

Originally Posted by Joshboody

Fuel type won't make a difference as far as i know.

Any datalogs to match up?

Correct. Fuel type won't make a difference to the test. And since all three cars had plenty of octane, they wouldn't run into knock-induced AFR richening. The Procede car took logs. Not sure about the other two. The owners would have to chime in on that if they wanted to.

shiv

[thebigragu99]

Originally Posted by Joshboody

Fuel type won't make a difference as far as i know.

Any datalogs to match up?

it would.

[Mike@N54Tuning.com]

Originally Posted by Joshboody

Fuel type won't make a difference as far as i know.

Any datalogs to match up?

Running methanol enables you to basically hit any air/fuel ratio you want provided the o2_biasing resistors are properly sized. You bypass the whole fuel trims issue that everyone not on methanol is dealing with. Not sure what the point of this comparison is either.

Mike

[MAC335i]

I think its kinda obvious... The Cobb and JB4 both have a bump up in AFR and the procede does not.

I think he is showing how the procede controls fuel/targets AFRs "differently" (read: "better") than other tunes.

amirite

[OpenFlash]

Originally Posted by Mike@N54Tuning.com

Running methanol enables you to basically hit any air/fuel ratio you want provided the o2_biasing resistors are properly sized. You bypass the whole fuel trims issue that everyone not on methanol is dealing with. Not sure what the point of this comparison is either.

Mike

Incorrect Terry. Running methanol will allow you to hit the AFR targets but will require less additive fuel trim (all other things equal). The only time running meth will allow you to hit your AFR targets is if running without meth results in max'd out fuel trims. Which is not the case here.

[Joshboody]

Originally Posted by thebigragu99

it would.

explain? My understanding is that WB measures the amount of oxygen added or removed from stoich. This means fuel type would not matter.

Originally Posted by Mike@N54Tuning.com

Running methanol enables you to basically hit any air/fuel ratio you want provided the o2_biasing resistors are properly sized. You bypass the whole fuel trims issue that everyone not on methanol is dealing with. Not sure what the point of this comparison is either.

Mike

Nobody should be maxing trims, since all tunes have the ability to alter fuel requirements. If AFR improves on meth, then off-meth tuning is not configured correctly.

[thebigragu99]

Originally Posted by mikeclark111

I think its kinda obvious... The Cobb and JB4 both have a bump up in AFR and the procede does not.

I think he is showing how the procede controls fuel/targets AFRs "differently" (read: "better") than other tunes.

amirite

Actually,the v3 is all over the place from going to rich,then lean,and back to rich again.

[OpenFlash]

Originally Posted by Joshboody

explain? My understanding is that WB measures the amount of oxygen added or removed from stoich. This means fuel type would not matter.


Nobody should be maxing trims, since all tunes have the ability to alter fuel requirements. If AFR improves on meth, then off-meth tuning is not configured correctly.

Correct on both accounts.

[vasillalov]

Ok,

So now that we have AFR logs from three cars with somewhat similar mods, the following question must be answered:

What is considered a proper AFR for this DI engine across the different rpm ranges? Why?

[vasillalov]

Also, for the sake of comparison, here is a bone stock dyno showing stock AFRs:

[RambleJ]

For this to be a true comparo, all the cars would need to be in the same fuel type. Either all meth/pump or all 100oct. This is worthless.

[Mike@N54Tuning.com]

Originally Posted by Joshboody

explain? My understanding is that WB measures the amount of oxygen added or removed from stoich. This means fuel type would not matter.


Nobody should be maxing trims, since all tunes have the ability to alter fuel requirements. If AFR improves on meth, then off-meth tuning is not configured correctly.

It's very easy to max out trims down low on a race gas map. Of course the fuel pressure mapping (FPMapping variable in the JB4) determines the open loop fueling and fuel trims. The fuel table determines the AFR target or o2_bias. If I were offering advice to whomever did the JB4 run I would suggest they increase the fuel pressure mapping as it looks like they are maxing out the fuel trims on spool up. In one of the newer beta firmwares that system has actually been redesigned and fuel trims added as a loggable parameter. Now if they are running meth they can go 100 all across on the fuel table to run as rich as they want without much worry of maxing out the fuel trims on stock turbos.

Mike