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Title: KFZW differences for different cams. Post by: basshunter98 on November 03, 2023, 04:59:35 AM Hi guys! I've been comparing two ME7.9.10 maps from two different cars with basically the same engine.
The first car is rated at 120hp and that the second one at 160hp with a slightly longer duration camshaft and a ""bigger""(+3mm) compressor wheel. The first sw allows for maximum turbo pressure of 0.8 bar, at about 150 load while the second has the capacity to peak at 1.2 bar, at about 180/190 load. I have never seen such a dramatic difference in the KFZW map, especially in the high load/high rpm areas. In fact, it occurs to me that in the first version the engineers were so lazy that they tuned only the useful cells and then extrapolated all the rest, resulting in ~18-21 degs at high rpm and mid/high boost which could be destructive if not taken care of while increasing the boost. Below are the KFZW maps (TOP = 120hp, BOT = 160hp). Note they come from stock files and are correctly defined and triple-checked with IDA. (https://i.imgur.com/G5O03KU.png) Also i'm really having an hard time understanding why in both maps there are ATDC cells while building boost considering that some of them are consistently reached even by both stock tunes as confirmed by my logs (especially the ones at ~2000/3000 rpm given the tiny turbo). Also, what the hell is wrong with the 5520 rpm row in the 160hp map?? Are there any pros out there able to enlighten me on these three questions I have? Title: Re: KFZW differences for different cams. Post by: prj on November 03, 2023, 05:05:50 AM First of all, an engine is not an Excel sheet.
Second, your answer for 120hp is correct - the higher load cells were not tuned because the engine does not make this load, so who cares what is there. Camshaft and turbo makes a large difference too. Above 5500 rpm on second map it is either not tuned because engine never reaches this load or with that load after 5500rpm you have massive EMP and a lot of knock. I am not sure what staring at the map will give to you though. Take the car and log the knock and tune it. Who the f cares what there is from factory? Or if you want to understand it, then do a pull with the car, log everything and then trace it over the map and see where it reads from. As for negative timing on spool - if the engine has very high CR then it's completely normal that it has negative timing there. Otherwise it would knock. Title: Re: KFZW differences for different cams. Post by: basshunter98 on November 03, 2023, 06:40:31 AM First of all, an engine is not an Excel sheet. Second, your answer for 120hp is correct - the higher load cells were not tuned because the engine does not make this load, so who cares what is there. Camshaft and turbo makes a large difference too. Above 5500 rpm on second map it is either not tuned because engine never reaches this load or with that load after 5500rpm you have massive EMP and a lot of knock. --- As for negative timing on spool - if the engine has very high CR then it's completely normal that it has negative timing there. Otherwise it would knock. Gotcha, thank you for clearing up my doubts. Also im kinda speechless regarding the lazyness and inconsistency of OEM tuners. I am not sure what staring at the map will give to you though. Take the car and log the knock and tune it. Who the f cares what there is from factory? Or if you want to understand it, then do a pull with the car, log everything and then trace it over the map and see where it reads from. Totally agree with you and already did the tracing thingy on stock boost for both cars. I just needed someone to confirm my theory that I should temporarily fix that part of KFZW before doing any pulls and attempting to tune the car for higher loads than stock. Most tuners in my area dont even know this, I keep wondering how many innocent pistons they have blown holes in. |