Amber Gramps

AMEN

oh I got the other chip, AMEN anyway

Dave Thomas

Make that HUNDREDS, maybe even a thousand. And A-freakin-MEN.

scarceller

I have been burning my own chips for about a year and I have installed a WideBand O2 data logger in my Modified 86 Euro Carrera 3.2L. The logger lets me log the following:
AFR
RPM
WOT Switch
Air Flow Meter signal 0-5v

I'm a EE by education and a Software Engineer by trade, I also worked with these 2732 and 2764 chips extensively in the 80s while doing EE work so I'm at home working on these devices. the 27xx chips are UV-EPROMs that MUST be erased in a UV Oven so I converted my 24pin DME to take a 28pin 2864 chip which is a EEPROM (electric erased chip) these chips can be erased directly by the burner and thus makes re-burning them easy. Also the 2864 can hold 2 times more data than the stock 2732 so I have the stock map in the lower half and the tuned custom map in the upper half, when I modified the DME I added a switch that lets me flip between the 2 maps at will, even while driving the car. I can tell you for sure my throttle response is far better with the custom chip map. Read on to learn more.

I do not sell anything and make 0 $$ at this. I can tell you for certain that Steve Wong's tunning approach is SOLID and works! Steve has helped me along my study and learning process and I have learned much from him. All I can say is if you give your car to Steve to tune you are in good hands.

Now, the question is 'should I buy an off the shelf chip?' the trouble here is that these type of chips are NOT tuned for your engine. They are general purpose chips and ussually they are tuned in the part throttle maps to impove throttle response under load. Doing this causes the mixture to go rich under load (13AFR or so) when you step on the gas. But here is the rub, if you have an o2 sensor and it's connected to the DME then while in the part throttle maps you just defeated the purpose of the tuned maps because the DME will see the AFR is rich (13.0) and just simply pull it back up to (14.7). So you would think to just run the car with the O2 disconnected which is exactly what you should do to get the advantages of the tuned part throttle maps. BUT, if you have stock US exhaust with the CAT in place you risk damaging the CAT.

The other area that the chips tune for is Wide Open Throttle (WOT) and from the work I have done I tend to think the Factory went overly rich with these maps just to be on the safe side, my car was down around 12.5 AFR with the stock chip. I have learned from certain experts not just on Porsches but other cars as well that the magic AFR for WOT seems to be between 12.8 and 13.0 with it dipping closer to 12.8 at RPMs above 4000. I also noticed that my AFR was not really constant across the RPM range at WOT. But my car is not stock it is a 86 Euro engine with WebCams 20/21, Port and Polished intake, SSI and a 2in2out open pipe. So my WOT AFR curve had several low and high points that went from 12.5 up to 13.2, once I saw the curve I could then simply start tunning the values in the WOT map to flatten the curve across the RPMs to 13.0.

The other issue is that what if your car is not running correctly in the first place? (which is offten the case) If Fuel Pressure is off, the AFM is out of calibration, you have air leaks, ... the list goes on. Then putting in another chip won't help.

The last area that the tuners tune is the Timing Maps, in my opinion a lot of gain can be had here since the timing maps seem to have been conservitive by design from the factory. I suspect this was done because the engineers could not control the type of fuel a customer would use. If you use 93octane you could go more agressive that with 86 octane. I think the factory maps where just playing it safe here. Now, the issue is you BETTER know what you are doing to tune these! Folks like Steve have spent many, many long hours on dynos fine tuning these and playing the dance between detonation and power. I really think this is the magic! My car came with a Steve Wong custom chip for my motor and it's custom setup. I did NOT and will NOT touch the timing, I'm just sticking to what Steve did. However, I am fine tunning my Fuel Maps and can see the results with my WideBand O2 logging setup. Once I'm done and happy the car goes to the dyno.

In the end, my opinion is you can get decent rewsults from off the shelf chips but if you are really getting into chip tunning you should go all the way and have your car dynoed and tuned by having a custom built chip made from the dyno results. But before you do this you MUST be 100% certain your car is mechanicly correct and has no faulty components or air leaks.

I mean no disrespect to any member on this board, just sharing my experience with tuning the 3.2L by burning chips.

ked

My God! new, knowlegable & polite... this isn't going to go over very well.
{many thanks & welcome, scarceller}

Amber Gramps

OK, who let this guy in? Nice car, nice attitude, nice knowledge base, this can't be happening? Welcome aboard. Can we get some pictures?

Chip related question: Why will my car always fire 100% of the time on first tap with my stock chip, but not fire 100% of the time with my aftermarket chip on first tap of the key?

scarceller

Thanks for the warm welcome.

First, I'm new here but have posts on Pelican for sometime.
You may be intrested in this one:
http://forums.pelicanparts.com/showthread.php?t=364450

Now, for your question. Not sure what chip you have but the bottom line is somthing must be set diffrent in the custom chip, most custom chip creators start with one of the stock chips and alter it. So the chance that they started with your stock chip as a base is very unlikely. These chips not only contain the 6 or so maps that most tuners tune (3 for fuel and 3 for ignition) they also contain about 30 more maps and data points. Much of this other data is rarely spoken about but the chip has startup maps used while the engine is cold it also has intial settings for fuel and spark while cranking. By now you should be getting the idea. So the bad news is that unless someone reads your data off the stock chip (that starts well) and the custom chip, once you have both sets of data files you simply do an file diffrence (fdiff) on them to see what's diffrent. Someone with knowlge of the chips would expect diffrences to be found in the 6 basic maps but would be lokking for anything else that's diffrent else where. You get the idea. My bet is something in the data utilized while in crank mode is diffrent.

Another approach would be to copy the 6 maps from the custom chip and maybe the rev limit data if altered and move just this to your stock chip.

Also worth a note is the idle speed wich is diffrent for 84 chip vs say 87 stock chips. 84 idle was 800RPM while 87 was 880RPM.

Bottom line is you have no idea what base chip the creator of your custom chip started with.

scarceller

OK, here are some pictures of my modified DME. I piggybacked the WideBand O2 controller directly onto the DME. Meaning the Wideband O2 controller is just wired into the internals of the DME I did this so I did not splice into any wire harness to install the WideBand O2 system. Just figured it was easy to find another DME box if I destroyed the curent one.

Then I also modified the chip socket to take a 2864 EEPROM and added a switch to toggle between the stock maps and the custom maps. Think of it this way: it's like I have 2 chips in the box at all times, 1 is the stock chip the other is the custom tuned chip and then the switch let's me select one or the other on the fly.

Amber Gramps

I believe my stock chip is the 2864. It's the one Steve Wong says is the better of the stock chips. I sent it to Russell Berry at MaxHPkit to read prior to his burning me my "custom" or "aftermarket" chip. Next week the car goes in for it's first check up in 20 years. It smells like it is running rich, so I'm really confused.....

scarceller

I'm not 100% but I think the 6 maps that are mostly customized by the chip creators have very little if anything to do with initial startup. Meaning they are most likely not used at all during cranking phase. This is why my bet is something other than those 6 maps is diffrent between the chips.

You wouldn't happen to have your custom chip image as a .bin file would you?

Also, what year is your car? I have many of the factory chip images myself. If your chip is a 2764 it's an 8k chip and must be from an late87-89 DME box. 84 to early 87 DMEs used 2732 4 k chips.

The 8K chips are 28pin and the early 4k are 24pin so should be easy to tell. Good news is if you have the 28pin larger chip then it must be 87-89 program. I have the bin file for the USA cars.

If you have or can get the bin file for your custom chip I'd be glad to take a peek.

Also, If your stock chip has a label please please post the partnumber

rberry951

I'm not sure what makes you think it's a good idea for someone to send you my work. I didn't spend 20+ hours on the dyno and 10K miles of tuning just to hand it to someone else.

Douglas' chip was created from his stock bin file, modified with my performance mappings. I haven't changed the cold start fuel enrichment, nor timing advance in my chips. I only do that with MAF cars, usually turbos.

Regards,
Russell

Amber Gramps

Russell, Sal, Sal, Russell. Now that we have the formalities out of the way, what did I start here? Don't worry Russell, My chip isn't going anywhere. Sal, I don't think it's the chip that is the problem. I think it is one of the other pieces of equpment involved. It could be the O2 sensor, TPS, MAF, Idle setting on the cruise control cable, or any number of other things. The chip is actually unbelievable. It was added as just part of an overall restoration and I would have to give most of the credit for performance gains to it. The valve adjustment really helped, but the chip really smoothed out the climb thru the RPM's. I simply figured that with experiance in this area of tuning you, Sal, may know right off what would keep the car from firing at first tap. Russell had his suggestions and I have not yet taken it to a qualified shop to test the list of possible causes. When I get my tax return then we will know for sure....Sorry guys If I sparked any contention here.

rberry951

No contention, you did nothing wrong. Neither did Sal. He's been on my forum for a while now. I do not believe he means anything wrong at all, I sincerely believe he is just trying to be helpful. But I know the forums, and other vendors would get him banned, or tag him as another Loren. And he's a good fellow, I don't want to see that happen.

Russell

scarceller

Russell,

Thanks for understanding. I did not mean anything harmful. I was just trying to help a fellow Porsche owner. It really was that simple.

I'll be more carefull in the future in how I offer to help.

It did not even cross my mind about mis-using your chip in any way.

Thanks for being understanding.

Sal.

Amber Gramps

My stock chip is 1267355358 for what it's worth....

scarceller

1267355358 is a stock chip for 89 USA Carrera. This is one of the better chips the only other more agressive stock chip I know of was the 89 Euro chip. A few better Porsche chips do exist but only for specialty cars ie: ClubSport.