86 951 Driver

Since this thread has been derailed. I remember there being a post about a company that manufacturers harnesses for old Mercedes. I would think that they could also do a Porsche Harness no problem. No idea on cost, but it seems like that would help our cars out a lot.

On the subject of the A Tune, did you ever run Vitesse chips for the AFM?

zerMATT951

It sounds as if you could be in a position to start building 944 Turbo wiring harnesses and raking in the cash!

User 52121

Wow who pee'd in your Cheerios this morning?

zerMATT951

Apparently labor is free...

Hey, so I live 8 miles from Mouser and my office is across the street from Allied Electronics (and a good friend of mine is a marketing manager there). I should be able to pick up whatever connectors are needed, possibly for a discount. So I'll volunteer to help with that side of the new wiring harness building & group buy venture!

User 52121

Vitesse *AFM* chip - no.

So far I've run stock, Weltmeister, Lindsey, and (for a very brief period) some form of Turbo Cup chip. (And of course the A-Tune.)

There's only so much one can do with a tune from behind the constraints of the original software strategy. There is no magic bullet - you're not going to pull 100hp out of a tune in these cars, keeping all other things equal. The stock strategy has a lot of limitations, you have to make a lot of assumptions. Plus the way it uses 3 tables is kinda goofy and horribly inefficient. They did what they could for the technology and knowledge they had at the time.

The performance most tuners find out of the stock strategy (Lindsey, Vitesse, Welt, Autothority, etc.) is going to be mostly equal. One might have a tad more mid-range, or a little more top end, but at the end of the day I bet you're talking only by a percent or two difference. Based on manufacturing and wear variances, one tune might work "better" on one specific vehicle than another - whereas you might flip flop those results on a different vehicle. But I bet that, on average, they're all going to be about the same.

Realize that Porsche had a lot more requirements to meet, being a manufacturer of new vehicles, in their engine control software. They had to make sure that the software was adaptable enough to cover manufacturing variances - for not only performance and driveability (so one 944 Turbo drives the same off the lot as the next one - at least similarly enough that the customer can't tell the difference), but emissions too. (In fact I can promise you that emissions compliance was #1 priority, with everything else falling in behind that.) Hence stock tunes leave a little on the table - they need to ensure that they will operate just as properly on cars built at 2:00 on a Wednesday as cars built right before happy hour at 4:30 on a Friday. Having been in the software engineering side for an engine manufacturer, I speak from experience - the EPA is a *bitch* to deal with. They will show up at the plant at random, pull a handful of vehicles right off the production line, and test them. If they don't pass emissions regs within a certain percentage - the whole line gets shut down until you can prove you've resolved the issue. Trust me - you don't want to be one of the folks responsible for having a production line shut down. (EDIT: Speaking from experience with a US manufacturer, of course. No, the EPA probably won't show up in Germany... but I'm sure they probably tested random cars off the boat as they arrived in port - and if enough didn't pass, they would've stopped importing until the issue was resolved...)

So by narrowing that tune window down, you can generally pick up some power in most cases. My guess is that's also why some chips work better than others, and some have a reputation (like Autothority) for running lean and causing engine failures. Completely my own made up theory here, but as an example to hopefully better illustrate my point: Whoever came up with that tune probably happened to test on cars that were all closer to the "rich" end of the spectrum, leaned them out, made power... but now the occasional rare car that's running on the "lean" end of the spectrum goes TOO lean and kaboom. Etc. My bet - Those cars were probably way on one end of the fuel flow tolerance range to start with.

The advantage of the Rogue stuff is that Josh rewrote the code. He doesn't use the original 3-table setup. As far as I know - he's the ONLY one who does this. Everybody else still uses the original 3-table setup to some degree. So he was able to find more mid-range power and torque than the others, by using tables with more dimensions and capacities and adding information that wasn't there before (MAP signal) which allows the DME to better select the appropriate fuel and timing for the boost level (vs. making an assumption based on pre-determined, hard-coded values in a table.) And even with this - once you consider flat-out, wide open throttle performance - the A-Tune probably doesn't really vary much in power output from the others (so long as you're comparing the A-Tune against a different tune that's running the boost level it was designed for.) The benefit is in the part-throttle stuff.

zerMATT951

Pretty much sums it up:



My car is a daily-driver on a 92-mile (round trip) commute. I don't have many opportunities to hit full boost during that drive in traffic, but I am able to tip into the throttle pretty regularly and get 3-5-9-13 PSI, and the car is an animal even at those boost levels. I smile every time I drive the car... even in traffic!