Blown Interceptor

iTrader: (5)

I have spent the last two hours reading threads about how everyone should get their car to the dyno for the A/F readings...I totally agree with that. A wide band tune is the best way to get the best A/F reading, but what I don't understand, is if you have Ram Air(like I do,VaraRam), how the heck am I gonna get a TRUE reading from the wide band if my car is sitting in one place, and not moving??? The only way I have to determine my "A/F", is by the scanner in HP TUners, which if you know, it is just like A-Tap.

It would seem to me, that there is alot more air coming into the motor at above 40mph and would be hard to tune. Anyone have any thoughts???

Thanks,
Jason

P Mack

iTrader: (6)

If your tune is right, the ram air won't change your air/fuel ratio because the pcm will account for any extra air. Just like it shouldn't matter if you're at 90% throttle or 100% throttle.

Oh yeah, and since you have hptuners, you might as well buy an lc1 wideband and the enhanced interface so you can do wideband tuning yourself. It'll be cheaper than a dyno tune and you can sell it when you're done.

SSpeedracer

iTrader: (8)

I've got a FTRA, sealed lid, K&N filter and descreened MAF. (MAF is clean w/out any K&N juice on it)

My wide band reading indicates leaner AFR at different MPH while keeping everything else the same. In other words, as speed increases A/F ratio decreases. The difference is slight at about .1-.2 AFR. I dont know if more air is actually getting in or if the velocity profile across the MAF is changing. Maybe its a combination of the two.

I'll only know whats up if I ever dyno tune. But since I dont drive to work on a dyno, nor race on a dyno, it is not a priority.

slow

iTrader: (7)

racing on a dyno is fun

What kind of wideband are you using, and is your commanded air fuel changing (assuming no)

Ryan

P Mack

iTrader: (6)

If you had hptuners it would be easy to look at the maf and map to see if more air is getting in. I guess I could look but I don't have ram air.

Blown Interceptor

iTrader: (5)

I think it is a DynoJet?

Here is the place: http://www.thedynoshop.com/

The problem I see is, when I got my car dynoed(NA), my A/F was 12.4-12.8. When I look at the O2 senors, I see 870-910, is that correct? Those numbers mean I am running lean, right?

Blown Interceptor

iTrader: (5)

I am still learning HP Tuners, where would I look on the log file?

Thanks,

P Mack

iTrader: (6)

You should look in the chart display. Should be easy to compare the max maf reading in different gears.

Pro Mouse

iTrader: (15)

.870-.910 doesnt mean your running lean or rich.You need wide band to know for sure.My Tuner Had my A/F @ 12.6 to 12.8 my Auto Tap runs where at .900 to .920 so dont try to dial in your A/F for WOT without Wide Band o2's...

SSpeedracer

iTrader: (8)

PLX Devices. Commanded afr varies slightly 12.5 to 12.7 per the PE muliplier v RPM table.

WB reads dead on commanded AFR for 15-50 mph, .05 rich for 55-80 mph, .15 rich for 80-100 mph, and .25 rich for 105-135 mph. Vaccum was 98+/-1 KPa for all WOT data.

Comparing data at the same RPM points indicates the MAF is over reporting air as the mph increases. Since manifold pressure is always the same, the air velocity profile through the MAF must be changing. I tuned the MAF at lower speeds.

SSpdDmon

iTrader: (10)

I'm in the same situation with my SSRA. I'm fairly certain the car is leaning out to the point of knock retard at 100+mph. The answer to this is to tune it on the road if you ask me. If the ram air is truly altering the airflow characteristics of the motor, then that should be represented in the speed density tune as a change in manifold pressure. If you dial in all your MAP vs. RPM cells in the VE table, then you should be fine. Finish up the tune with lining up the P/E & WOT tuning. Then, the trick would be to recalibrate the MAF sensor because that will be off without a doubt. That's the path I've chosen. Now the only problem is I have to figure out how to do that with my LC-1 and copy of EFILive when all of you are talking HPTuners terms.

SSpeedracer

iTrader: (8)

The VE table is dead on (short of drastic weather changes). Dialed it in via speed density tune using many 0-140mph runs. The VE did not change relative to speed. At least not enough to show up during scans. In other words, same air mass per RPM regardless of speed.

The air is turbulent and has an undeveloped profile when it hits the MAF. I doubt more air mass is entering since the MAP never shifts more than .2 psi from 50+ mph and VE tuning indicated no change. More than likely, the MAF is calibrated for speeds below ~80MPH. Above 80 MPH and the air velocity profile changes enough that the MAF cant meeter it accurately (error ~2%).