A.Wayne

Not the same for everyone

Raceboy

Converting a CIS car to EFI is worth every penny! Of course, it may turn into nightmare when one is not capable of doing all by himself and ends up with a tuner who doesn't have a clue about tuning.
But that's an exception, not a rule.

LukeSportsman

+10 on the idea of finding a local tuner and checking into what systems he's familiar with in the past. There are many systems out there but a simple one in good hands will outperform the most elaborate ECU with no experience. I've been down this road a few times and if its your first time, just get a system your tuner understands......they will all be superior to CIS. Going by your other questions, it doesn't sound like your out to scorch the earth so most EFI's out there will be sufficient. Sure some like Motronic will/can be superior, but if you lack a laptop computer.......SDS might even be superior. BUT buy a laptop and a wideband O2 gauge.

Geoffrey

This year I was asked to present on the topic of MoTeC Engine management at the PCA Tech Tactics event and I have posted the slides I used on my Racetek Engineering Website

WERK-I

Excellent presentation, Geoffrey.

Geoffrey

See my presentation, if someone regrets going to EFI, then it wasn't done properly.

Porschefile

Those are some pretty broad and general complaints that I've heard many make of the CIS as well. The problem is doing things right. I'd say more often than not, people with poor performing or horribly setup aftermarket efi setups either paid an incompetent shop to do the conversion, or else tried to do it themselves without having a proper knowledge of the operational mechanics behind every aspect of an engine management, fuel injection, and ignition system. Fallible human beings and a resultant poor tune is usually never the fault of the hardware.

NineMeister

To back up Geoffrey's comments, have a look at these results from a 964RS that eventually arrived at our doorstep after having a Motec conversion done elsewhere. Apparently it had been at the 3rd party's shop (and then another just down the road) for around 10 months and this was the best that it would run.
We simply upgraded it to the full 9m Motec package (by fitting a set of larger injectors and the 9m intake pipe/filter) then remapped the car starting from our base program. It took only 7 full throttle pulls on the dyno to achieve the optimum power/torque result shown on the graph. After a further hour or so of road fine tuning and a couple of cold start checks the car was done, happily starting from cold & idling without hunting and would pull 5th gear uphill with zero throttle. Our new customer collected the car just 10 days after it arrived.

A.Wayne

It is not expensive , but if done wrong it can be , regarding CIS , if that is your level and you are happy with it, fine. Your argument is no different to the carburator vs fuel infection argument and you would have a hard time convincing that crowd to go CIS , as they have heard all the bad FI stories already.

Colin are you using a gear calibrated dyno ?

Raceboy

Having seen all the things that CIS has to "offer" and having a direct and first hand comparison to EFI benefits, there is not much to discuss at all.
Wayne pointed out just right about the carb vs FI evelasting argument.

Only occasion when CIS is right to leave in place is when you get an original 964 3.6 Turbo or just a very low-mileage and pristine 930. And CIS only in order to keep the car original.

WERK-I

+1

RarlyL8

It is easy to say that "this system is superior" or "that system is inferior" when you only consider your own experiences and/or the random samplings of others, who may have their own agenda or limited experiences.

The one word that is typicaly left out of these discussions is "application".

Carbs, CIS, and EFI all have applications that favor their use. Factors such as the intended use of the vehicle, the skills required to DIY vs a check book machanic, and your budget should all be serious considerations.

ZX3 - you have posted some specific items you wish to implement. What is the reason you chose these items? Why do you want to go EFI? (this is not a trick question - it will narrow down the type of EFI system that is best for you or may point you toward another viable alernative).

Personally, I would not mix and match EFI components unless I planned to do the entire process myself. If you do not plan to do this yourself I would find a proven tuner, explain my exact needs and expectations, and use their proven system.

NineMeister

I'm not sure what you mean by "gear calibrated" but this may answer your question in a round-about way:

The system we use is a Bosch FLA203 2wd inertia dyno that is fitted with an additional eddy current brake, pretty similar to something like a Maha or Dyno Dynamics unit. The roller set has been fairly recently upgraded with Dynostar control hardware/software which can blend inertia and brake loads, but in this case the runs were done with just inertia load. The dyno measures rwhp on the way up the rpm range, then you clutch the car at peak revs and it measures the coastdown negative power from the tyres and final drive, the flywheel results shown are the sum of the measured rwhp & coastdown loss multiplied by the DIN correction factor (calculated by the on-board weather station).

As far as I am concerned we use our dyno as an internal comparative tool and pay little attention to the absolute accuracy of the numbers in comparison to other dynos, but that said most standard factory cars (including the 930, GT3, GT3RS, 997S, 968, etc) seem to measure exactly the quoted hp. In the case of this car we saw an approximate 25% improvement in engine performance with the ecu mapped correctly, happily the customer noticed a similar improvement through the seat of his pants!

ZX3tuning

Rarly,
good question!
basically we are aiming to improve the drivability and over all performance in all areas.
having looked around and talked to a bunch of people there is a serious lack of tuning knowledge with the CIS system in my area and even within a long drive in any direction. The people who "claim" to know what they are doing simply charge us for changing parts that, while they might make the car nicer to drive, they don't fix the problem we brought the car in for...

with the EFI conversion, i hope to be able to; clean up the drivability issues we have with CIS, trim back the fuel for better economy when not being pushed and have room for growth with our power goals.
while we are not looking to "scorch the earth" persay.... a TT conversion and hopefully 500-550rwhp with no lag are the end goals we are aiming for once the project is finsihed. When we bought the car it wasn't orignial and had some good upgrades already and thus the idea of keeping the "expierence of driving a 930" true to stock form hasn't even been entertained. Having put some seat time into this car and knowing my dad's driving skill, i need to make this a much MUCH easier car to drive when we take it out for the odd track day or AutoX.

i'm a pretty skilled tech but just don't know these cars and rather than just randomly reading thru threads and picking up parts that might not be what i need, i wanted to start a thread that would help me with the project and anyone else wanting to do the conversion.

I know from other communities that often the "tuners" or the guys who have done lots of these conversions will never give out all the info as it hurts their business to do so but then again, they also wont help you unless they already have your CC# to bill you!
Not a shot at anyone here that has added to this thread.

I'd like to use the DTA system as i'm somewhat familiar with it having played around with a few other cars running the EXP48 system.
other than that, i'm open to whatever will produce the best package.
Cost isn't so much of an issue as the end result. having gone thru big builds with other cars, cutting corners is something i've never been a fan of. "do it right, do it once" is a Motto i have worked by for years and will apply that here.

does that help?

RarlyL8

Huge help.
Future goals of 500+HP narrow the field considerably. Fortunately many EFI systems are flexible in their fuel delivery capacities. Swap out to bigger injectors and re-tune. At some point the idle begins to degrade as the injector size grows.
I came this close >< to buying a HalTech system a few years back that had dual injector banks. The engine was throwing down 600RWHP and drove like Grandma's car around town. There was a slight lag followed by whiplash during transition when the 2nd set of injectors kicked in.
It's a shame that there are no knowledgable CIS mechanics in your area. Most likely it would cost very little to get your car in good running condition so you could enjoy it while shopping and planning your EFI conversion.