3.0vs3.2

[svandamme]

Originally Posted by island911

Yeah, a lot of people move away from MFI as it is a mechanical computer. (complex and difficult to understand)

Props to Jeff Higgins for remapping MFI to a 3.0 - carbs would have been so much easier.

changing displacement isn't to much of a problem on MFI
as long as the cam on the pump matches the engine camshafts, it should work just fine. its just enrichement which the pump had plenty of adjustment room for.

[aigel]

They are very similar. The injection system is probably the biggest difference indeed. I had good luck with the CIS on my SC. If this is a car question (SC vs. Carrera), go for the better car and let the engine be secondary. If this is about what engine to buy to put into xyz, then the 3.2 is probably the easier solution, unless you are changing the air/fuel delivery.

[mattdavis11]

I think the 3.0 probably could have put out close to same horsepower if it had the variable valve timing and lift electronic control that the 3.2 has.

The 3.0 has one huge advantage over the 3.2 though. If the 3.0 blows a timing belt, no worries about bent valves.


































I'm trying to save this thread from getting moved from off-topic. You're welcome.

[Bill Douglas]

Yep, with a SC you just check the oil and water, and drive off towards the horizon as fast as you can.

[911 Rod]

What a bunch of bored old guys we are

OP asked a question without details to not return and we are on page 3 rambling on

[Bill Douglas]

I'll wait until I've had another beer before I give an authoritative answer...

3.0 and 3.2 are goth good. but some are gooder than the previous goodest.

[Jeff Higgins]

Originally Posted by Shaun @ Tru6

I think the 85+ wheel is one of the most handsome modern wheels ever made and iconic Carrera. But it's huge. For driving, this wheel in the 73 is more my taste.

Great minds think alike. My favorite steering wheel in my favorite car:

[Jeff Higgins]

Throwing MFI into this mix rally isn't fair. Neither motor came with it originally, unless we're talking Euro Carreras and RSR's.

Converting either motor to MFI will completely, absolutely change its personality while adding a noticeable bump in power. Both systems that followed it represent a compromise in performance in the name of emissions requirements. Drive MFI and experience how God and Butzi really meant these cars to be.

[rusnak]

The later G-series 911s handle much better than the earlier ones.

I don't know 100% why. Perhaps the chassis are stiffer, better roll bar technology, etc. But I have noticed that the '84 through '89 911s are far better than the mid-year or SC as far as grip and that feeling of confidence at initial turn in.

[island911]

Originally Posted by Bill Douglas

Yep, with a SC you just check the oil and water, and drive off towards the horizon as fast as you can.

But only if you know that you can depend on the performance of cross-drilled brake lines.

[Racerbvd]

Originally Posted by Jeff Higgins

Throwing MFI into this mix rally isn't fair. Neither motor came with it originally, unless we're talking Euro Carreras and RSR's.

Converting either motor to MFI will completely, absolutely change its personality while adding a noticeable bump in power. Both systems that followed it represent a compromise in performance in the name of emissions requirements. Drive MFI and experience how God and Butzi really meant these cars to be.

While we are at it, the 46 Webers and Twin plug helped the 3.0 for my 914-6 GT clone
And when comparing the slightly modified 3.0 (cams, SSIs and a few other things) in my old 83 cab, to the low mileage 88 Carrera 3.2, without a doubt the 3.0 is much more lively.

[Jeff Higgins]

Yeah, either carbs or MFI will certainly make any 3.0 more "lively". CIS is just that bad, from a performance standpoint. Don't see many 3.2's converted to carbs or MFI, which says a lot.

Driving either one in stock form, I have to say, feels like my right foot is pressing into a block of clay.

[Bill Douglas]

In 28 years of SC ownership (I don't want to temp fate by saying this) I've done almost nothing to the CIS. It's a '82 ROW engine that has been balanced and rev's like a Honda - what's not to like.

Any faster and I'd be upside down, down a bank, so the car suits me perfectly. I'm a nice sensible boy who doesn't drive faster that 235 kmh (146mph).

[island911]

same, no CIS issues

Originally Posted by Jeff Higgins

Yeah, either carbs or MFI will certainly make any 3.0 more "lively". CIS is just that bad, from a performance standpoint. Don't see many 3.2's converted to carbs or MFI, which says a lot.

Driving either one in stock form, I have to say, feels like my right foot is pressing into a block of clay.

Still, there is a big difference between the two.

I recall a dyno-day where I drove a euro Carrera that I had just seen putting up the big HP numbers. Driving it I first thought it was just my power expectations being too high. Nope. Got back into my less than stock HP SC and enjoyed much snappier throttle response. It did not pull nearly as hard on throttle, but the snappy throttle was there.

Come to think of it, driving (previously Warren's) 73S (stock w/ MFI) that felt very SC like. The snappiest I've driven was likely a carb'd 2.7 in a 1972. I have yet to drive an EFI car that feels snappy.

[Jeff Higgins]

I have driven way too many MFI inducted cars that are an embarrassment to the breed. Way too many. I've tuned every one of them (that's why I was driving them) to bring out that "snap" for which they are known.

Now, I'm still a rank amateur on all of this, but I have noticed a trend that has repeated itself in every MFI car that I ever tuned that had been running like a dog. I believe it is attributable to one step, and just one step that is documented in the CMA manual - the idle CO2 adjustment. Setting it to the factory spec appears to result in a very, very lean running condition. And they run like crap.

IMHO, this was a period effort to meet ever tightening emissions. Set per the numbers found in CMA, they pass emissions. And run like crap. Back then, of course, wide band O2 sensors were still just a dream, so CO2 was all we had. Today, with readily available wide band O2 sensors, we can merely drive on down the road and get A/F ratios real time, under a broad variety of operating conditions. When tested this way, it becomes painfully obvious that, when the CO2 is set per CMA, the poor things are just too lean.

Correcting that changes everything. Unfortunately, "everything" includes significantly increased emissions and, with it, that infamous MFI stink. They like to run on the rich side, even richer than carbs. When made to do so, they become an entirely different animal.

This is, in a large part, why I'm rooting so enthusiastically for the electric car market. The more folks I see driving those things, the less guilty I feel. I figure for every couple hundred of those I see, I can sneak in one old school MFI car...

[svandamme]

Somebody should develop an electronic plugin to attach to the MFI pump
that connects to the rack adjustment.

Add a throttle sensor
an O2 bung
RPM sensor
Knock sensor
6 coil packs
Voila, Electronic self tuning with MFI throttle response.
As long as your Correlation is set, it could figure out all the rest and learn as you go
It would go like a raped ape

[island911]

Originally Posted by Jeff Higgins

... Set per the numbers found in CMA, they pass emissions. And run like crap. Back then, of course, wide band O2 sensors were still just a dream, so CO2 was all we had. Today, with readily available wide band O2 sensors, we can merely drive on down the road and get A/F ratios real time, under a broad variety of operating conditions. When tested this way, it becomes painfully obvious that, when the CO2 is set per CMA, the poor things are just too lean.

Correcting that changes everything. Unfortunately, "everything" includes significantly increased emissions and, with it, that infamous MFI stink. They like to run on the rich side, even richer than carbs. When made to do so, they become an entirely different animal.

.

Good points. I suppose i should note that my SC runs stronger w/o O₂ sensor attached, and dialed richer than OE spec. Still much leaner than the MFI or carb'd of course. Those things... I can't help but think of chasing an MFI car thinking "Porsche - Kills bugs fast" line - as the fumigation behind the car drops the bugs.

[Por_sha911]

Originally Posted by dewolf

Is a turbo

My answer: "No, but it is a hemi" (queue puzzled face of other person).

[Por_sha911]

One more major advantage of 3.2 in my `87:
G50 transmission. (Hmmm, I wonder if it was built by GLOCK?)

[Jeff Higgins]

Originally Posted by svandamme

Somebody should develop an electronic plugin to attach to the MFI pump
that connects to the rack adjustment.

Add a throttle sensor
an O2 bung
RPM sensor
Knock sensor
6 coil packs
Voila, Electronic self tuning with MFI throttle response.
As long as your Correlation is set, it could figure out all the rest and learn as you go
It would go like a raped ape

Ask and you shall receive. Not cheap, but full electronic control, replacing the entire governor half of the MFI pump. I'm sure you read German, so I won't need to translate for you.

Produktinfo - Elektromechanische Einspritzpumpe - Viktor Günther GmbH / VGS-Motorsport



Unsere eigens entwickelte elektromechanische Einspritzpumpe lässt jede herkömmliche Einspritzpumpe im Schatten stehen. Mit Hilfe eines elektronischen Stellers wird die Gesamtfunktionalität der Kraftstoffzuteilung nun elektronisch gesteuert. Rotierende Masse und unnötiges Gewicht werden somit überflüssig.

Die MFI2ECI (mechanical fuel injection to electronically controlled injection) wird direkt an das im Originalzustand bleibende mechanische Hochdruckelement angeschlossen. Die mechanischen Steuerungselemente der Pumpe (bestehend aus: Drehzahlregler, Warmlaufsteller, Höhenkorrektur und DK-Stelleinheit werden demontiert ohne dabei die Mechanik zu beschädigen. Bei Bedarf lässt sich die Pumpe außerdem jederzeit wieder auf den Originalzustand zurücksetzen.