kens911

Why cant a 3.2 efi system be used to convert a 3.3 to efi without having to add a motec or megasqirt etc. All the correct sensors seem to be there. It seems you should me able to use the motroninc box and just reprogem the chip, with as many people out there already reprogramming motronic chips I would think it woul be a very economical way to switch to efi. Is there something basic I am missing? I have been doing a little research and all of the sensors evry one adds for all the different efi systems are contained in the 3.2 system. looks like you should be able to change the mass air flow sensor and reprogram the chip with a map that works with a turbo, add a overboost switch and relay.This would also look much better no crappy looking digital display boxes mounted in variuos places in the car every thing would still look stock and use the stock 3.2 wiring harness

Geoffrey

Crappy looking digital display boxes??? Who's installations are you looking at?

Several things come to mind, first, the 3.2 Carrera system is a very very old motronics setup which does not do sequential injection. This in itself is not really an issue, but just represents old technology. Second, the 3.2 system uses an air flow meter to measure engine load and as you mention needs to be changed to something else since a turbo engine will have the AFM sensor at 5v (max) before the engine is on boost which means there would be no way to meter additional fuel. Changing to a MAF would as you suggest require rescaling of the code. However, it also requires a TPS so the ECU can do acceleration enrichment since the MAF cannot respond quick enough to changes in throttle opening. The 3.2 Carrera does not have a potentiometer style TPS, but rather a switch.

Todd at Protomotive has done exactly what you mention except he is using a MAP sensor for load rather than a MAF.

kens911

Oh ok the digital display box I was refering to was the one on the SDS system not sure about the motec or the rest. anything other than the stock gauges would look out of place to me. so if I switched to efi went with a motec system would i pull the kjetronic box out and toss it? then replace the whole wiring harness? After going through the fuel pumps not wanting to run deal with this thing and still not having it solved this cis is really starting to bug me, on the flip side I have had the engine out of my 3.2 carrera several times. Always runs and works flawlessly.

Geoffrey

Any efi system, MoTeC or otherwise would generally consist of a square box as the ECU, and a wire harness similer to a 3.2 Carrera which would replace the CIS parts in the car now. Depending on how you installed it, and how you finished off your wire harness, it could be unnoticable, or it could be much nicer than stock, or it could look like crap. Basically, it is all up-to-you. I converted my turbo in 96 to MoTeC and is still running today after some hard track miles and two engine rebuilds, neither related to any issues from EFI, just wear from the track. It also served as a daily driver for awhile. EFI is not that big of a deal.

kens911

oh ok so you tossed the kjetroninc box the motec will do everything that it did? I would have no problem replacing it with something that works better but would have a problem adding extra boxes etc. should get mine back from the second trip to the body shop this week So hopefully I can spend Thanksgiving underneath it trying to figure out why the fuel pumps will not run.

fast951

The idea of using a 3.2L Motronic for the 930 is very sound, you get the factory look and feel, you inherit all of the drivability characteristics of the factory systems. The Motronic has many features that a very few know about.
We just added functionality and flexibility. We rewrote the code to offer semi-sequential injection, true MAF support (transfer function unique per MAF in the code). We also designed a Wasted Spark system to work with the Motronic (single or dual plug). We can program the Motronic to retard timing based on Intake Air Temps, Head Temps even boost. Large injectors support, with factory like drivability is there as well..
For data alogging and playback we offer the Motronic Monitor.. You want additional control over AFR and timing, we have a PiggyBack.

Check out our website, all of the systems for the 944/951 exist for the 3.2L..

We have designed many systems for the 951, we have the same technology for the 911.

edit: You can use all of the 3.2L sensors on a 3.3L, even the 930 starter ring. We can reprogram the code to understand the different number of teeth.

A.Wayne

WOW!

Contact the mods, he used Motec and megasquirt in the same sentence

kens911

ok thanks John. Wayne I'll bite whats the difference between the two? wasnt trying to step on any toes or promote anyone just wanted some info. hopefully I can get this CIS sorted out the other car is sooo much easier.

Porschefile

There's no reason you couldn't convert to the 3.2 Motronic, and it would be relatively inexpensive compared to some of the more exotic stuff like a Motec. It's decent enough compared to CIS, and many have been able to modify the 3.2 Motronic to perform well above and beyond the stock levels. Todd at Protomotive for one. I also have been pleasantly surprised with the tuning from John at Vitesse with regards to my 951's Motronic (which is very similar to the 3.2's motronic). I wouldn't have thought such an old efi would be capable of doing some of the things that have now been done. I also wouldn't have thought that our older efi systems could be made so adaptable to newer technology such as maf or map sensors, sequential injection, etc. Though, several reputable people have proven it's possible. On the flip side, once you get into the 3.2 Motronic the prices can really add up when you factor in a maf or map conversion cost and any other additional things. These costs can quickly add up close to or equal the cost of a technologically superior aftermarket efi which could provide superior performance with a proper tune. There's always tradeoffs. I'm currently dealing with this dillema at the moment. I already have the 3.2 Motronic with Todd's chips. For ~$2.2k I could have his map conversion. Though, for ~$4.4k I could also have an AEM ems from Chris @ Turbokraft, which opens up alot of other possibilities such as an AEM CDI ignition, true sequential injection, and a ton of other nice features which would ultimately provide better performance. At the risk of being flamed, there is also the piggyback route for efi of course. There are plenty of piggybacks available now that are so advanced that they are basically an aftermarket ems by themselves. Take the Greddy E-Manage for example. It features the ability to convert to full sequential injection, a map sensor, you can run a wideband interfaced for an initial "auto" tune, etc etc. There are plenty of people in non-Porsche communities making big hp reliably just with piggybacks. There's no reason that wouldn't apply to our motors as well. It's all a matter of tuning. Luckily technology is so much more widely available now that we have a heck of alot more options compared to a decade or 2 ago.

Generally, it seems when most people reach the point they want to convert to efi they tend to want to upgrade and get the best for their money as well as the best components available. True, many of these setups can be very expensive, however there are plenty of capable aftermarket ems' that can be setup for cheaper than some of the $10-20k+ prices I have heard in the past. Of course, most of those high prices are also including engine work as well as the technical know-how to get things done and tuned perfectly, which in itself is probably 90% of the battle. To many this is well worth the added cost. Though, we aren't all made of money so that route might not suit everyone. At the risk of starting another motronic vs. aftermarket efi war, many modern aftermarket efi systems are ultimately superior to the 3.2 motronic. Many have tried to argue otherwise, but it's like trying to argue that a 1ghz cpu is faster than a 2ghz processor. The core components of something like a Motec ecu, for example, are physically more advanced and are able to process data faster then the stuff available for the Motronic in the 80's, they have larger grids to tune at smaller rpm intervals, etc. That's a plain and simple truth that can't be argued. I could go into more detail, as could others more well versed on the subject (like Geoffery), but I don't want to get too OT. Anyways, the point of my statements is that I wouldn't completely discount the idea of an aftermarket efi. Setting one up on your own won't necessarily be a cake walk, and it will take lots of research and learning though so much of the info is just out there on the net for free if you have the time or patience. If you're looking for more of a plug and play solution, I'd consider just going with a 3.2 motronic and having someone like Todd at Protomotive tune some chips for you. That would, most likely, be the easiest and most cost effective way.

All of that being said the most important thing is tuning, period. It doesn't matter what kind of fuel injection you have, whether it be mfi or efi. If it's not tuned right then it won't perform well. This may seem obvious, however even the most archaic injection setups will still perform well when tuned right. If you go with an EFI setup, I'd highly recommend going with someone reputable to tune your aftermarket efi or motronic. Don't skimp on the tuning otherwise all of your efforts will be for nothing.

Kens911, just some basics are the Motec has more advanced and faster hardware and it's built with superior materials (milspec connectors, etc). It also has a more advanced tuning interface (at least from what I've seen). In addition, it features quite a bit more load sites to more finely tune at smaller rpm intervals. Those are just some of the basics I can think of. Sorry to type a novel. I have some strong feelings in the efi category!

kens911

Well thanks for the info just looking into it now out frustration with the CIS, I still have to get this one going then it's time for the carrera to get some tlc since I have been driving it to work every day, I really want to do it all myself Im just wired that way. sending the thing off for somone else to do it along with a large check, isnt my idea of building your own car.

fast951

Kens911, There are many ways to convert to EFI, Motronic is just one of them. Hardware prices are much less expensive per feature, many good standalones on the market. Reliability, ease of use, customer support, features are all important. Good luck with your search.

kens911

ok thanks!!
weather took a dip was to cold to paint so it looks like i dont get it back until next week

kens911

got the water tank for the windshield washers done it looks just like a stock slant nose water tank. kind of stunk up the house welding it with a soldering gun but it came out great. so the holiday wasnt a complete loss. one other thing any one know what a reasonable price for a set of carrera intake runners that were cut apart and ported then welded back together, also has dual injector ports. would less than 500 be reasonable?

Geoffrey

Dual injector ports are not required when using a modern EFI system.

kens911

oh ok saw one listed on e bay was wondering what it was worth or if I should bother bidding