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CIS to EFI Conversions?
I've stumbled upon a couple of sites on the internet claiming to offer "bolt-on" CIS to EFI conversions for 911's. Here is a picture of one on a turbo:
http://www.pelicanparts.com/ultimate...s/930ebay1.jpg Is this idea as nutty as it seems or might it be a cost effective (and potentially "greener") alternative to carbs? Has anyone actually tried any of these products? ------------------ Janus Cole 1980 911SC & 1987 944 |
Couldn't get to the page listed at the top of your pic? Any ideas?
Any other links? Sound like a good idea to me, but I need to see more. With all the efi tuners out there now, an affordable efi system seems doable - maybe not in the carb cost region, but you can't beat the performance. Matt |
Well, I found the following three websites...
<A HREF="http://www.injectionperfection.com.au/ " TARGET=_blank>http://www.injectionperfection.com.au/ </A> <A HREF="http://www.pem.com.au/ " TARGET=_blank>http://www.pem.com.au/ </A> <A HREF="http://www.sdsefi.com/ " TARGET=_blank>http://www.sdsefi.com/ </A> I'm definitely not qualified to evaluate any of their claims. I sent an email to the first company - I'd expect it will take a while to hear back because of the time zone differences. I am curious mainly for environmental reasons - I've avoided carbs because of the emissions issues. A halfway decent alternative to CIS could make me very happy. I'll keep you posted if I get a reply. ------------------ Janus Cole 1980 911SC & 1987 944 |
I just tried the links and found that I was getting some extra html tags at the end. They don't appear in the message - but they appear in the address bar when you click on the link. So I think you'll have to delete the "br" stuff appearing at the end of the address when you clik on it.
And just in case, here they are again without line breaks. Maybe this will help... http://www.pem.com.au/ http://www.sdsefi.com/ http://www.injectionperfection.com.au/ |
Janus
It is about midday when I type this in Australia. If they get off their butts you should get a quick answer. I got something from them once, took a couple of days. Price for a pair of triple throat throttle bodies was pretty reasonable, I think. I cant find the info though (and it is pissing me off!). Cam |
I am not aware of any complete ready to bolt on systems for the 911, but there are many EFI systems out there that can be used.
Here are a few, all are priced at less than a set of new PMOs: Emtech (Haltech of Australia) Haltech Electromotive DFI (Digital Fuel Injection) EFI Technology Zytech |
Autronic is also a good unit that I have heard good things about. I am running a Haltech E6K.
------------------ Mark The Beast mark@hargett.com |
Excuse me for butting in on this post with a question but what is required to change to a Haltech type system from CIS. Controllable injectors, air box?
------------------ Rob Fix '78 SC Targa |
Hey, I just checked out the website for "The Beast". It is a beauty !! Awesome job.
------------------ Janus Cole 1980 911SC & 1987 944 |
Thanks Janus.
Robfix, I'm not that familiar with the CIS but what you would need to do is install regular type injectors, supply them with fuel pressure, and then control them with the ems. ------------------ Mark The Beast mark@hargett.com |
to my narrow point of view, it's a carb eat carb fuel world, unless you are spending big bucks.
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I remember someone fitting a 4 barrel
carburetor to his 911. Why couldn't one of the aftermarket 4 barrel throttle body systems such as the holley projection be adapted to the existing cis runners? It would be tuneable for engine mods and forced induction. Has anyone tried these systems on their muscle cars? |
I'm planing to install SDS-system on my car.
triple throttle bodies per side is a bit of overkill, at least for a turbo...it's so much easier to pick up plenum-chambers from more recent 911 Carrera together with holes for injectors and fuel-rails. N/A engine might respond better to multiple throttles tough. EFI is *much* better solution than CIS, and more simple too... I'm dreaming about throwing out all CIS-maze, with modern EFI you can put air-filetr directly on turbo intake, connect the turbo directly to throttle and voilá...it works. all you need is dump valve and throttle-body potentiometer. You can throw out several kilograms of CIS-rubbish out of the engine bay. CIS is cumbersome, complicated and power-robbing system with air-flow meter sitting directly in the airflow.... EFI is cleaner, more fuel-efficient and simpler solution. |
Quote:
Actually, with a lot of reading on the subject, along with help from this BBS, I feel quite at home with CIS. On my car, it's working just fine. BTW...if you want a good overview of how CIS works, take a look at the article in the October Panorama (Pg. 86). ------------------ '81 SC Coupe (aka: "Blue Bomber") Member: SCWDP Canada West Region PCA The Blue Bomber's Website "If it ain't broke...we'll help you fix it 'til it is!" [This message has been edited by Doug Zielke (edited 11-04-2001).] |
...or what about 6 individual electro-mechanical injection plungers linked into a MoTeC brain? New World meets Olde World in a spectacular synergy of horsepower, sound and processing grunt....
------------------ '72 911 TE |
A guy in our local PCA chapter removed his CIS from his 79 SC and installed the DFI system. He was never happy with its performance gain and felt that the CIS did just as well. He ended up selling it saying the benefits were not worth the cost and work involved.
But that may be just the DFI system...not sure how others compare. Nick ------------------ _ _ __ _ _ Nick Shumaker 1982 911SC Coupe nickshu@yahoo.com |
CIS is wide-a***d, complicated way of doing things.
It cannot compensate for air-pressure or air temperature, and as generally cumbersome way of doing things. MFI was much better, altough dirtier way of doing things. EFI rules... It was probably a good solution 20 years ago...but by now it's obsolete. Even if i dont get a single horsepower from conversion (which i strongly doubt) , i would welcome additional MPG-increase with EFI. |
beepbeep - what system are you using to control injectors? Are you also replacing ignition?
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We use SDS on our 993 race car and on my 3.2L. On my carrera I have TWM throttle bodies with the SDS system. SDS is very reliable, easy to install and a fraction of the cost of most other managment systems. It uses a standard bosch style injector harness and has a driver for each set of three injectors with fuel mixture adjustment. All engine timing and fuel is controlled by computer and the engine map can easily be adjusted with the LED display at any time.
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The problem with using a 4 barrel carb is ensuring that the fuel distribution is the same to all the cylinders, to do that you need equal length runners , the CIS manifold doesn't have that so you would need to fabricate one yourself.
There was an interesting article in one of the Up-Fixin the Porsche issues that was written when Porsche first introduced the Vario-Ram system. It explained how Porsche motors has gone from a tuned intake on the Weber carbs that allowed for a 'full' cylinder charge (a ratio of 1, or the actual volume of the cylinder chamber at bdc) to less than 1 with the first CIS to greater than 1 with the vario-ram system. Any replacement manifold that isn't fed by a turbo charger needs to take into consideration this ram tuning effect or you can seriously impair the ability of the cylinder to fill properly. Robert [This message has been edited by rvanderpyl (edited 11-05-2001).] |
CIS is a simple, but dated system.
It does compensate for pressure and air desity by measuring the mass of air past the sensor plate. A modern day computerized fuel injection system is better because of the ability to map the mixture based on an almost infinite number of different conditions, and it does not have the sensor plate creating a "slight" restriction in the air flow. But, CIS systems make less HP on a N/A motor. Having said that, i do like the CIS system when it is maintained correctly. It is simple, bulletproof and cheaper to maintain, as long as the fuel is kept clean. You don't even need a laptop computer to work on it :-) It has it's quirks, but that is part of the charm of my car, at least to me. All the CIS systems on 911s are at least 28 years old and most are still functioning properly. We will have to wait to see if the motronic systems can match that reliability record without depleting the owner's bank account. Technology has come a long way, and shown great strides over the past 10 or 15 years. Maybe I am just too nostalgic? ------------------ Gerald Gore II (Sam) 73 914 350 small block (sold) 80 911SC [This message has been edited by sammyg2 (edited 11-05-2001).] |
I'd certainly agree with sammyg2. My CIS system seems almost unstoppable despite major problems with my car's plugs, oil lines, vacuum hoses etc. But a system which could deliver a few more ponies and maybe improve mileage and emissions is very attractive (the emissions issue is actually pretty important to me). Carbs are clearly the "bolt-on" mod of choice, but they are very environmentally dirty. So in the search for a "bolt-on"-ish alternative to CIS, it seems this thread has revealed at least one scenario:
1) Intake: Natchamp's Beast has an intake manifold from a 3.2 bolted onto a 3.0 litre case. This is a very elegant solution. It uses an OEM part which provides Porsche quality assurance plus it incorporates an intake manifold which is already designed for EFI. Very smart. I notice that an inch had to be removed from the runners. Was this because of the intercooler? One wonders if a 3.2 litre intake manifold could be bolted directly onto a 3.0 litre engine. If so, then that would be sweet. 2) Injectors: I am guessing that Matter's SDS system used regular Bosch injectors when he says the systems uses a "standard bosch style injector harness." If this means one could use another OEM part, then that would rock. 3) Engine Management System: Everyone seems to have a favorite. The Beast has a Haltech E6K. Matter uses SDS. Matt Smith mentioned MoTec - obviously Porsche agrees. I've never heard of anyone adding it on after the fact. But why not? So the big question is: What would this cost and how hard would it be to install? In other words, how would it compare to carbs? Honestly, if it came within a grand or two of the price of carbs, then I'd go for it if only to avoid the emissions hit. ------------------ Janus Cole 1980 911SC & 1987 944 |
Janus, I used a 3.2L manifold for the reasons you stated. I lowered it by 1" for clearence purposes for the intercooler which would not be needed. However, to mate the manifold to the 3.0L heads I did have to add some material to the heads where the manifold seals/bolts on. I'm not sure if this would be needed with all 3.2L manifolds or not and it wasn't that much work.
The fuel injectors used are the standard double o-ring type. If you buy a 3.2L manifold you might get the fuel rails too which would work great. Or you could fabricate your own like I did. What is important about the injectors is to match their size accordingly to the engine configeration. I am not referring to physical size here, but their amount of fuel they spew. There are simple calculations for this. You will get numerous opinions about EMS as you mentioned. One point of clarification in your note: Porsche uses Motronic which is not the same as Motec. Engine management systems are a whole topic of their own. ------------------ Mark The Beast mark@hargett.com |
Hey guys, nice discussion on the topic.
Just wondering. Has anyone used Webers as simple throttle bodies (delete fuel inlet and storage), then using an adapter under the carbs (possibly replacing the existing intake manifold to support/hold a fuel rail and injector for each intake port)? I've got MFI heads (w/Webers) with plugs in the factory ports. Is there an EFI injector that fits, perhaps bore out to fit? Sherwood Lee http://members.rennlist.org/911pcars |
One point of clarification in your note: Porsche uses Motronic which is not the same as Motec.
Oops ! My mistake. I was having a total brain fart when I typed that. Thanks for straightening that out. Since the 3.2 litre intake manifold and (possibly) fuel rails might be somewhat "bolt-able" to a 3.0 litre CIS engine, has anyone ever tried going the extra step and throwing in the OEM Motronic components? If salvaged from a wreck, then that might be a very cost-effective upgrade. Or maybe I'm pushing my luck. ------------------ Janus Cole 1980 911SC & 1987 944 |
Sherwood, I have a freind that was going to try and do just that, use the carbs for the function of the throttle bodies only and out the injectors into the manifold below them. I think its a great idea and would look cool too. I also like the idea of having individual butterflys closer to the cylinders.
------------------ Mark The Beast mark@hargett.com |
I don't have a huge amount of details (ie I have never seen it in person) but this engine has MFI throttle bodies bored out to 40mm and adapted for use with electronic injectors (MoTeC controlled). I have no idea how tricky this was but I bet it was cheaper than a set of TWM bodies. You would just need to find a set from someone who has given up on MFI (ie if the pump is shot).
Actually, I am probably going to buy it, but won't get it for a couple of months http://www.pelicanparts.com/ultimate/biggrin.gif http://www.pelicanparts.com/ultimate...LM911%203L.jpg ------------------ Cameron Baudinet 1975 911S (in bits) 1969 911T |
Since I can't stand the looks or the upgrade restrictions of CIS I've been doing some research on this. I very much like he idea of using the 3.2 intake setup. The throttle body approach is attractive but very expensive. Clewett engineering offers a fairly complete kit for the SC using the 3.2 intakes etc, for about $2,500 ( In the ball park with PMOs) with after market EMS. Check out Http://www.clewett.com go to Catalogue and engine management systems. I haven't contacted them for details yet.
Jeff C 81 SC |
I have done business with Richard, he's a stand up guy. When you talk to him, ask him why he cut and welded the 3.2L manifold to have the inlet point in the other direction as seen on his website. The 3.2L manifols will fit in either direction. I was contimplating cutting mine to do the same thing until I realized it fit both ways.
------------------ Mark The Beast mark@hargett.com |
I just received my SDS system two days ago, for my '83 SC. I will be using Jenvey throttle bodies (www.jenvey.co.uk), which I expect to get sometime next week.
IMG SRC="http://www.pelicanparts.com/ultimate/image_uploads/sdsefi1.jpg" |
II6:
Yummy! Tell us how it's working out for you! I'm also taking SDS-path as soon as my wallet allows it. I'm thinking about using later Carrera-style intake with injectors and rails. Are you going to lower fuel-pressure to 3-bar?? |
II6,
Please post some more pics when you get some I am VERY interested in trying this myself. I am thinking of trying to get a DME manifold instead of TB's. Also what comes on the ecu as far as mappings? Do you have to set the whole thing up from scratch? Ben in SC |
What type of sensors do you have to add as inputs to the brain.
head temp? position sensors? Is a MAF used? I'm interested in this topic, but skeptical. Cause "real Porsches don't have computers" http://www.pelicanparts.com/ultimate/smile.gif ------------------ Bill Krause '79 911SC Euro MY PELICAN GALLERY |
I did a CIS to EFI conversion on a 78 3.0 a while back and used components off an 85 Chevy 2.8 V6.
What I ended up with was a very responsive, powerful and fuel efficient 3.0 that included all the "on board diagnostics", hot film mass air flow sensor, head temp sensor, throttle position sensor, computer controlled HEI ignition, Bosch injectors, complete wire harness, etc. all for less than $150 from the local boneyard. I'll post some pictures of my modified intake manifold and air box later. Fun winter project. Joe Garcia 86 Carrera Redwood PCA since 1976 [This message has been edited by stlrj (edited 11-07-2001).] |
I'm thinking about using later Carrera-style intake with injectors and rails.
BeepBeep, I was thinking of exactly the same plan on the theory that "Real Porsches use Porsche parts." http://www.pelicanparts.com/support/smileys/lol2.gif Has anyone ever tried using that setup on a 3.0 using the OEM Motronic brain (maybe with 3.2 litre cylinders bolted on)? I am thinking that taking the entire air/fuel injection system from a wrecked 3.2 and "bolting" it on to my 3.0 could be cost effective and OEM. Is there any reason why I am way off base? ------------------ Janus Cole 1980 911SC & 1987 944 |
What I ended up with was a very responsive, powerful and fuel efficient 3.0 ... for less than $150 from the local boneyard.
STRLJ: I stand corrected !! If you can tell us how you did this conversion, then I'll gladly give it a try. Sounds great! I'll have to modify my mantra to "Real Porsches go REAL fast." ------------------ Janus Cole 1980 911SC & 1987 944 |
Here's my manifold, not as pretty as a 3.2 setup, but it's functional and cost effective.
http://www.pelicanparts.com/ultimate..._0014.JPG1.jpg http://www.pelicanparts.com/ultimate..._0015.JPG1.jpg http://www.pelicanparts.com/ultimate..._0016.JPG1.jpg Joe |
Joe,
Any more info on the model of FI that you used? I thought most of the GM FI was of the TBI type where the injectors sat on top of a central throttle body? Any pics of the setup after installation... As you can tell many of us are VERY interested... Ben in SC |
Glad to see that picture, because now I know that intake manifolds can have curves in all directions. I guess all the intake manifolds for all cylinders must be same length though.
Wonder how this kinda setup (curved "pipes") will work for example with Holley which has this "central" for jets. |
Joe, Can you elaborate on that a little bit? Is that just the CIS Airbox with the top cut off?
Tom Curious as hell. ------------------ 82 911SC Coupe |
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