BTW I did modify both my stock intake boxes by cutting out the big plastic grill in front of air filters so Im wondering if my higher reading helps with this at all. I wish I would of done before the mod measurements. here is the link to what I did https://www.jaguarforums.com/forum/x...rboxes-165613/
Also my G/S measurement is with Eurocharged tune. Im going to turn it off and run it with stock file to see if there is a flow change.

 

Crap I hope we are not fighting an uphill battle. If its true, any mods without this limiter removed are worthless.
I wonder if tuners address this at all
Maybe we can get Eurocharged and other tuners to chime in on this.

 

Not sure where the limit is when the ECU steps in (probably not with just a upper pulley), but you can also see it in your recordings if the airflow suddenly drops to a ECU regulated flow. Or you can do another recording with just the throttle opening.

With the airflow value you only record a voltage from the MAF to which the ECU maps an then an estimated airflow, so the number will depend on the accuracy which as we know change over time. You can't measure any other improvements from tunes that alter the timing/fueling obviously. Last but not least, air density/temperature at the time of measurement plays a role as well, so without any corrections there, it will not be something you can use to compare with other cars (or your own runs!), its just a rough ballpark, and a cheap way to check if you have made improvements on the airflow only.

 

Wow Thats pretty darn impressive on how close Maf readings are to your actual whp numbers

383 g/s x .95 is 363 Dynojet WHP , and you got 361 whp on your dyno run

 

What we really need is someone with a dead stock XKR to make the same tests and see what sort of numbers they get, I won't be in a position to do this for a while unfortunately...

 

Indeed, hindsight is 20/20...

 

My ex-JLR contact lifts this limit value in his tunes. You can ask others, see what they say, I think most don't/can't change this, maybe some can, I don't know everyones capabilities in detail.

I don't know the exact number of the limit either but he says he reached it when developing his tune on his XKR... with a pulley, no cats & exhaust mods (x-pipe).

 

The changes made in airflow he made are of course more then "just a upper pulley", but it shows that it is not far off.

My 1st experience with this limiter was on an early 2005 PanPag ECU for a RR where we had to lift this limit. This was for a TS at a higher airflow then just a pulley for the Eaton, but of course limits could be different with Jaguars software.

 

I did runs tonight comparing Stock, Eurocharged tune and OE tune
somewhat confusing results.
I have logs for all of the experiments so if anyone wants to take a look let me know what can be understood.

Im not an expert but Eurocharged tune looks very similar to stock, where OE tune is very different and feel way more powerful in everyday driving

First was the Eurocharged tune, 388, 390, 383 g/s

Second stock 385, 379, 380

Third and last run was OE tune which runs crazy rich and was slower than stock on a 1/4mi but pulled 392, 388, 384

 

Thanks for making the effort to do that.

Some head scratching required for sure here...

The only mechanical mod on your car is the 1.5 pulley yeah?

 

Pulley and the stock air filter box mod with the plastic grill being cut out and discarded.

 

I did a check, but there are to much sensors selected to make a gr/s comparison obvioulsy, but you can see the Eurocharged tune is better because of the (big) timing advance, roughly 3 to 4 degrees more, and that could possible be about 25 rwhp or so.

One thing noticeable is that the engine load isn't 100%, so you may want to check if the ECU is holding it all back (so only select throttle opening). One thing to note, the ECU can also go into safe mode (similar action as with the torque limiter) if you hit the rev limiter hard, once done, it will only go back if you restart the engine.

 

Avos
thanks for checking the logs. Any idea why OE tune feels like it has a lot more torque down in lower rpm band?
Also you say eurocharged looks better with the timing increase but G/S show it only has 5+7 crank HP over stock which is a tiny gain not worth the tune Id say

 

What would you define as midrange? I only looked at max power from 5000rpm, and then I don't know what to trust in figures (ie is the value for the a/f ratio correct?) etc.

Normally after a tune change I would make sure to drive a while 1st to see all settling down, to be sure there is nothing left in memory that could affect the readings. But I have no direct experience with the PanPag unit you have, as I see the fuel trims (memory) remains the same at wot over the 3 runs.

Please note that with your current logs you can't use the MAF gr/sec for mentioned reasons, so there isn't much I can get out of that. Next to that there can always be a small variance.

 

Are we able to see how much hp/air flow is robbed when the aircon is running

 

Usually WOT cuts out the a/c.

 

• ​​​​​afr ratios should be correct but they max out at 12.17 , so do not show any richer than that. Up to 3500rpms OE tune feels like it has 50 extra lb of torque compared to stock and eurocharged tune, I can see it goes rich with this tune as soon as a push the throttle slightly.Not sure the extra torque has to do with it being rich or maybe there is something else in OE tune that's giving it the extra power. Why can't we use the g/s again? It seems acurate and logs happen more than a few time/second

 

As I already explained in the other thread, as soon as you go full throttle past a certain load the WOT Enrichment mode in the ECU kicks in and the O2 sensors are turned off. There is a commanded AFR but the actual AFR is not monitored by the PCM, and only the last value measured before the switchoff is broadcast via OBD2, which just happens to be 12.7

But the timing in the log doesn't exactly match up because there are so many measurements being recorded some are lagging behind.

Like for example, in your logs of the stock tune, timestamps 49:52.7 to 49:53.4, you've gone full throttle but there are identical numbers for the MAF, Fuel Trim %, etc, but some others are changing. This is a massive lag, in reality every split second these values are changing, but you cannot capture it. And then from 49:53.4 to 49:53.5 the MAF rate jumps from 97.91 to 266, that's not how it happens.

In the meatime during that period the PCM has switch to WOT enrichment, the O2 sensors are "off" and it's not until 49:53.8 that the logger has caught up on that measurment and is displaying the last number the PCM got before it switched off the O2's. It's about a full second behind the numbers recorded for the engine load. The MAF data is also "running late" as is the RPM's...

 

This is an interesting thread, I tried this to supplement my power runs. In third gear I saw peak readings of 441g/s which equates to approximately 485bhp or just over 400 to the wheels. This makes me pretty sure that when I had the smaller pulley on a week ago, I would've been over 500HP at the engine

Let's see if I can get back over it with some more mods.

 

Thats a impressive number if thats not a 5.0 engine
what mods do you have?