NineMeister

I am sure that we could help you/Geoffrey with start maps for either ecu, or alternatively send one over and we could pre-map it on one of our own cars first.

Reynard38

I can see myself going this route someday. I have thought about forced induction, but the cleanliness of 350 NA horsepower wins out everytime. When the time comes for the top-end rebuild I can only hope that Colin will have an affiliated shop here in the US.
Hey Colin the weather is great here in Atlanta!

JasonAndreas

Would you by chance have the eproms already removed from the ECU or extracted onto your computer?

Lorenfb

"I am sure that we could help you/Geoffrey with start maps for either ecu, or alternatively send one over and we could pre-map it on one of our own cars first."

1. For less than $100, you can buy an EPROM reader/programmer.
2. There are numerous free PC programs on-line which will provide
a remapping capability, e.g. the 944 Rennlist Form.

Bottom line: Twenty year old stuff/efforts which generally yields little.

Caveman

Hi Loren,

I have no affiliations to any of the other listers on this post but your comments come across as a bit negative given what seems to be a genuine offer of assistance? I've seen a lot of cars over here where remapping to suit a particular car (rather than just creating a generic chip for a car) has given some great results.

Regards,

David

Bill Verburg

I've got the original e-prom from the M64/21, I had a new one burned when I put the RS kit onto the engine.

except for the idle it runs great

Do you have a need?

NineMeister

Loren,
I respect your opinion, but I cannot agree with you that for $100 anyone could achieve the same results, nor can I agree with you that it yields little in this case. I'm not going to get into a debate about this, but I would guess that there are plenty of others who could back up our findings with respect to live dyno remapping.
KR

Lorenfb

"I respect your opinion, but I cannot agree with you that for $100 anyone could achieve the same results, nor can I agree with you that it yields little in this case."

Issue 1: the availability of the necessary tools
Solution 1: most/all, given the internet, can easily buy the tools for less $500

Issue: 2: remapping a chip
Solution 2: very basic PC & software knowledge needed

Issue 3: maximizing torque -> to max HP
Solution 3: access to a dyno & A/F info

Issue 4: minimize remapping development time
Solution 4: buy an EPROM emulator $1000 (not necessary for one time remap)

They teach the above in most high school auto shops now,
so most high school kids or computer geeks are "at home"
with doing this!

Bottom line: Check out the Rennlist 944 Forum, those guys do it
all the time.

Red rooster

Loren,
I know how you feel about this remapping subject but I believe your aversion is leading you to make contradictory statements ?

1. $500
2. $ ? mapping software + correct map identification and calibration factors.
3.$?? Dyno time @ $100 + / hour
4.$ 1000 for a simple emulator . $2-3000 for something useful.

A quick addition leads to a little more than $100 !!

An important detail ommitted was the experience to be able to recognise a succesful calibration .
Can I ask if you have attempted this task yourself . Even on the simplest 3.2 DME ?
I and many others in the motor calibration business, both OE and aftermarket, dont share your view that this is such an easy task to get right !

All the best

Geoff

pcar964

While the physical task of remapping might be relatively straightforward, I would think experience with the particular engine is key. All the same, I would rather have someone like Colin do the mapping Even though I've never met the guy, he's one of the few people I would trust my car with.

Lorenfb

"An important detail ommitted was the experience to be able to recognise a succesful calibration . "

Some can and others can't, e.g. some shops can work on a '73 911 but when
it comes to ODBII and complicated diagnosics have trouble moving from a
ratchet to a Porsche tester PST2. For those that are willing to read & learn,
remapping is not a big deal!

"Can I ask if you have attempted this task yourself ."

Yes, many times, mainly to solve overly aggressive timing maps which "push"
the limits and enter the detonation region to achieve the desired performance "feel".

As I said, check out the Rennlist 944 guys. They're on top of it and exemplify the
basic simplicity of the process. They've got their web site which has a disassembler &
a first class remapper (3D).

Cost Issue: You just have to know the right sources or where to find them for the tools,
e.g. Rennlist 944 guys know how to find the "deals".

Additionaliy, check out the Rennlist 928 guys, as they're like the 944 guys
when it comes to DIY. John Speake (JDSPorsche - Rennlist sponsor) has a
unique remapping system which is virtually self-tweaking, i.e. each map cell
is optimized for a desired AFR.

Reynard38

We are argueing about reamapping the ECU? Seems like most of those extra 70 ponies are coming from the heads. Obviously you will require the remap after the install, but I'd want the guy who came up with the heads and has a proven package to do the work on my car.

Geoffrey

There is a large difference between the 88pin Bosch Motronics ECU found in the 993 and the earlier 55pin Bosch ECU found in the ROW 993 and earlier 964 series cars (we won't even begin to talk about the simple 944/3.2 Carrera ECU). The later 993 ECU is more complex, and I believe that the chip is soldered on the PC board using surface mount technology rather than through the PC board or in a socket like the earlier ECUs. Just this alone adds to the complexity of gaining access to the chip for reading and replacement with an eeprom.

Properly remapping an engine is not something anyone can do. Sure, its not hard to look at software and understand what makes numbers do what, but to properly make changes without risking engine damage is not well understood. I see this all the time with my students in the EFI University classes, even at the professional level. Last class I had some guys from a Grand Am DP team. Further, you need access to the proper dyno, not just ANY dyno. You need to be able to hold a load so you can adjust the timing to determine the optimum spark angle and very few chassis dynos can do this adequately. The additional power is going to come from the ignition timing optimization not the air/fuel ratio. The proper air/fuel ratio is going to keep the engine cool enough and within a normal range will have very little to do with outright power.

If access to proper software that allows real time emulation and mapping as well as access to the chips without desoldering were easy, I would have already done it.

Red9

There is a big difference when you can buy a replacement engine for $250! At that price you can afford to educate yourself. My other observation"a little knowledge is a dangerous thing" .Especially when you decide to start advising oyher people.

NineMeister

In the UK we charge around £5-600 to live remap a 993 on our chassis dyno. This is not a chip job, it is a full 3D remap of ignition and fuel maps from 25% to 100% throttle, from 1250 to 7000rpm during static rpm hold and roll-on inertia pulls. The job typically takes around 4-5hrs from scratch, so when you take into account that we charge £100/hr for the dyno if you used Loren's logic you could argue that you acutually get the remapping work for free, hence undercutting his $100 by a nice 100% margin.

As Geoffrey says, the principles of remapping a car is pretty straightforward but the practise of doing it is entirely different, but I cannot see the logic of advising novices to do it themself with their fresh $20k engine build in order to save less than 5% of the cost of the job.

So, swiftly moving on.....