Doug&Julie

Just want to post a topic for discussion and get some thoughts here. I have a 1974 911 (note, not an "S") that has a recently (and properly) rebuilt motor. Overall it's a strong motor and has never given me any real troubles. However it does have the stock CIS and it does not run...er...perfectly. I'm not going to fix the CIS system...I hate it...but I'm curious as to what might be a better "return on investment" as a replacement.

My first thought is a Bitz Racing EFI kit on the otherwise stock motor. I've read a lot of people like this and, once programmed, gives great drivability...if minimally increased power.

But then before the holidays I was able to drive a friend's '77 with a 3.2 conversion. The torque is so nice to have (although it doesn't feel like it has "neck snapping" power) and of course the EFI means smooth running.

But of course the 3.2 conversion will be two to three times the expense (even if I could do the work myself...which I can't). So I'm wondering if it would be worth it? My ultimate goal is to have a more tractable, driveable (mostly street driven) car.

Note, I'm not a power monger and my 2.7, as it sits, gives satisfactory power. Not great. But not bad. I'm...fine with it.

Thanks in advance.

Doug&Julie

Here's our girl...

theiceman

hey isn't that a rennlist Calender car ?

Doug&Julie

Miss September!

BReyes

Very nice ride.

Wasn't 74 the first year of forced induction?

Regards,

Doug&Julie

Thanks. Not sure what the first year of forced induction was...for some reason I want to say '76?

Auto_Werks 3.6

Doug, I know you don't want to hear this, but I think the most cost effective solution would be to pay someone to work the kinks out of your CIS. I drove an SC with stock injection for years, and it only ever missed a tick when I needed to replace the injector seals. I would think the second most cost effective solution would be to find a nice set of carbs. This is known technology, and most indy mechanics would be able to help you set it up. I think you will have a lot of time developing a proper tune on a custom EFI, unless you find someone who is very familiar with that system, and maybe has a base map. Other than that, I think you will have a bunch of money paying someone to tune it. I still think fixing the CIS is the cheapest route if you know someone who knows the ins and outs.

Doug&Julie

Thanks for your thoughts. FWIW I'm not trying to find the cheapest route, but the best "investment" to make regarding my induction.

I'm not a fan of CIS...I think it's an overly complicated "technology" that is becoming harder and harder to fix and find parts for. I simply have no desire to dump money into it...because that's what I feel like I'd be doing...dumping money. (..*ducks for cover from CIS lovers*..)

Carbs...I'm not afraid of 'em, but if I want to drive this car regularly, I would appreciate the better mileage and driveability from an EFI motor. I know that sounds very "non-enthusiast-like", but I find too many excuses not to drive this car already. I don't want mileage or driveability to be another one.

So that leaves me with EFI...and I'm trying to decide if I'll get a better return for my dollars by converting my CIS or going to a larger EFI motor. A lot of factors in there, I guess, but would love to hear thought from y'all.

Thanks again.

Auto_Werks 3.6

My opinion is that a full 3.2 conversion would be a better "investment", if you can call any porsche modification an investment. I think you would have at least 6k in a complete 3.2 engine, and at least a couple grand in having it installed. Does a '74 have the 901, or 915 gear box? That might also be a consideration. The nice thing about the swap is that when the dust settles you can sell the fresh 2.7 and get some of your money back. In the end I would think the 74 would be worth a little extra with a well done 3.2 conversion, where as I don't think you would get much of a premium for a 2.7 with custom EFI. That's just my opinion, but I think the unknown injection would scare off non tech savy potential buyers. Honestly if you are thinking of selling the car soon, maybe you should sell as is, and buy a 3.2 carrera. You've owned a lot of porsches, so you know how the game works. Conversion projects are much more cost effective for the DIY guys, because you can throw as much time at the project as it requires without going into the red.

g-50cab

Save your money and do the 3.2 swap - it will mate well to your 915 box. When you switch out - get new reference and cylinder head sensors. The stock heat exchangers with a premuffler and sport muffler and steve wong chip will get you the most bang for your buck.

Then you can get in - turn the key and go - your car will perform, it will idle well - and with the added HP of the 3.2 will run like a scalded ape.

I personally would not bother modifying a 2.7 engine.

DWalker

If I had a fresh 2.7 I would leave well enough alone and spend the money to do the EFI conversion. If you want a bit more power, swap out the cams while your in there, as the CIS cams are horrible (this is because CIS doesnt like big cams, and so the CIS cars have possibly the most docile cams Porsche ever put in a 911). There is nothing to be afraid of with EFI, and while I am not sure its for the average user, there are enough knowledgable people out there working with it that there is sure to be someone in your area that will sort you out just fine.
The 3.2 is going to be an expensive hoice for a used motor, and a more expensive choice for a refreshed used motor. Honestly "if it were me" and I was removing a freshly built motor only another freshly built motor would find its way back in. In the case of the 3.2, I would probably bump up the displacement a bit more during the refresh, do a nice set of cams, and maybe a set of headers. The problem is that I would never do this with a fresh 2.7 under the hood.

EDIT: If your in our part of the country (Colorado) I would be happy to help you in any way I can, we do EFI tuning and conversions on a lot of different things.

g-50cab

Oh didn't read the part that the motor was recently rebuilt "right" if right means line bored, shuffle pinned, time certed - then yes - I would add EFI or do what Art did and put a set of carbs on it.

Doug&Julie

Thanks again for the thoughts. I think you can see my dilema...perfectly good motor already in with minor upgrades vs. larger motor but with who knows reliability? (Although, I feel pretty comfortable about my knowledge of what to look for in a motor and, overall, I know the 3.2 motors are very reliable.) I will say also add that buying a used motor would be the very top of my budget for this project. So, in other words, I wouldn't have any money to "improve" or "fix" that motor should the need arrise. So no 3.4 twin plug rebuilds...

I suppose the next thing I need to do is talk to my indy mechanic and see how he feels about the EFI conversions since it'll be up to him to work it out.

Re: selling the car...I made a promise to myself to stop buying and selling so often (if at all), so I'm trying to keep this one. When possible, I'd like to add in the future, but that's only after I've pretty much worked this one out. Besides, I can't sell the car I got married in!

flatsixnut

I am no expert but from what I have read and been told, a "nice" running CIS system is hard to beat for overall reliability. Also from what I have read/heard is that once a CIS system went bad, it was then a good time to switch to carbs. I have also read some good things about Blitz Racing EFI, which made me think about switching. I currently do not have a problem with my CIS but I "may" have another serious issue that would cause me an expensive soloution...I will start a new thread so as not to go off topic in here.

I would think that if your 2.7 is recently rebuilt and its CIS is running fine, and you are not really seeking more power...just keep what you have until you really need to make the choice.

Auto_Werks 3.6

If it were me, I would check this out:
http://forums.pelicanparts.com/showthread.php?t=452690

I don't know the poster at all, so this is by no means an endorsement of what he's selling, but it looks like a good buy.