cknaak

Apologies in advance for the book....

Howdy all, I bought my 87 951 in November and it is pretty heavily modified. I have been slowly figuring out whats what while fixing the PO's shotty work here and there. Overall, its a great car but there's still a few items I'm addressing.

Anyways, today I finally got around to playing with the Mafterburner software(already installed) as I recently added a new SFR MAF kit to replace a home made setup that was on the car when purchased. While using the software it didnt seem like I was really able to make much of an impact.

I did some research on this board and I saw some suggestions stating that the DME/KLR needed to be burned with the appropriate mods to set a good baseline. BUT, I also saw some posts that said it didn't matter what Chip you have in the car because the DME is totally tunable by the Mafterburner. see why I'm confused?

I pulled the chip out of the DME and I have a Lindsey Racing chip that is setup for mods slightly better than stock. My car has a bigger turbo, injectors, 3' exhaust, boost enhancer and many other performance parts.

SO this brings me to my big question. Do I need to buy a new set of chips that take into account all my mods or does it even matter because of the MAfterburner software because I can totally customize the tune of the car? Do I need both? What do I do? If I don't need to spend the money on new chips great! If I will get more performance by doing so then I will buy new chips.

Also, do the DME chips come in different sizes for different years? I understand the DME and KLR are different sizes. I have a spare set of LR chips that have a tune closer to my setup but the DME chip was slightly to big for my DME? Strange...

944CS

First, find out what boost your chips are burned for

Get Rid of the boost enhancer, that should be your #1

Get 2 wastegate shims from Lindsey

Use either the factory electronic boost control, or an aftermarket (stay away from MBC)

Then call me!

cknaak

944CS, thanks for the response. I wil call Lindsey today and see if I can find out what boost the chip is set for. Since I'm still learning all this could you help me understand why the boost enhancer should be removed and why I need the Wastegate shims. Just trying to understand for my self.

The car does have a a boost controller installed up under the dash on the drivers side(I assume its aftermarket). I've only messed with it a little.

Paulyy

In other words you have 2 boost controllers. The boost enhancer shouldn't be there unless the PO was using this to keep the wastegate closed for a longer time IF the stock wastegate is still there.
To answer your question, You can use the mafterburner to change the volt curve from the MAF. It would help if there's a wide band o2 sensor installed to see the AFRs.

cknaak

Hi Paulyy, after doing some digging it appears I made a mistake when I said I had a boost enhancer. There is no mention of it anywhere in my paper work and after what you just said it wouldn't make any sense as to why it would be there. My car actually has a LR dual port wastgate installed already and I have an AEM WBO2 sensor to see the AFRs.

Back to my original question does it matter what chip I have in the car if I have the Mafterburner? The car seems to run lean and I haven't really been able to make much of change when I used the Mafterburner software. The chip in the car isnt really matched to all the mods.

JohnKoaWood

Yes the chip matters, the chips contain the fuel and timing maps, the mafterburner only modifies the signal being fed to the DME, the DME then uses that signal to select the appropriate field out of the fuel and timing tables (maps) on the chip.

ALSO of note, the above applies to the DME chip, MOST aftermarket KLR chips are noting more than duplicates of the stock KLR... notice I said MOST not ALL... if you are running a dual port WG, and aftermarket boost controller the KLR is doing little more than control the boost gauge in the dash (if it is still hooked up) and listen for knock to retard timing... little more, but not really germain to your question...

My recomendation would be emmulator and custom tune, but I am biased.. a set of chips from either lindsey, or Russel Berry (www.maxhpkit.com) would be the second best way to go... and FWIW LR gets their chips from Russel... but the LR chips are a custom tune setup different than what russel sells directly IIRC....

You either need new chips for your current setup, or a chip emmulator with a full custom tune... or you could just dive in head first and go full stand alone!

m73m95

You would also have to use the correct size injectors for the chip. Injector scaling is coded on the chip.

If your chip is tuned for 55lb injectors, and you have 80lb installed, you will be running WAY to rich.... or vise versa.

cknaak

Thanks John, your post really clears up a lot. When you say full stand alone what do you mean?

cknaak

ahhh, and the Mafterburner cant correct this? I know there is a selection in the interface that allows you to choose what sized injectors you have to get the correct fuel map.

JohnKoaWood

Stand alone engine management system, would remove the need for the Mafterburner, and really the MAF as well... but is a little bit more involved than modifying the curve of the mafterburner...

There was recently a Tec3 system for sale on here for around 2K ready to be installed...

cknaak

I think I will stick with a custom tune or chips. Thanks for the info

JohnKoaWood

Also worth considdering, IIRC it is cheaper and easier to change the chips than the injectors.. just food for thought..

BTW, an ostrich2 emmulator and MaxTune from Russel will set you back a few clams, but are well worth the investment if you ever plan on making additional changes, bumping boost pressure, or any additional mods... I ran this setup for over 2 years and loved being able to fine tune for new injectors, higher or lower boost pressure, exhaust changes.. or just change the fuel and ignition maps on a whim.. some times while driving down the road!

MaxTune while not required for this all to work (see roageant DIY tune thread) it does make life easy for loading the maps and creating the chip image, not to mention it is pre-set with the memory addresses of MANY different Porsches, not just the 944...

cknaak

So I just got off the phone with Mike at Lindsey Racing and he basically told me the chip tune doesn't really mater with Mafterburner as its fully customizable through user interface. He also told me to call back tomorrow and talk to Dave as he better suited to answer tuning questions. Now I'm slightly confused again. i hope Dave can clear some things up for me when I talk to him.

86 951 Driver

Lindsey Racing should be able to help you out since you have most of their stuff anyways. I have always had great luck with them. I would make sure you have a list of all mods on the car so they can help you a little better. Instead of guessing what kind of injectors, turbo, and all that you have.

m73m95

There are actually a few more things to adjust than just the maps when changing the size of injectors.

If you're using the stock O2 sensor, it adjusts fuel on a percentage.... 5-10% more/less fuel to maintain 14.7AFR

10% fuel on a 55lb injector is a lot less fuel than 10% of an 80lb injector..... Meaning the stock O2 sensor will swing the AFRs wildly rich/lean with 80lb injectors....

I don't know that much about the mafterburner, or lindsays setup....just stating the differences in injector size, and how the DME reacts.