any perf. upgrades for 72 911 mfi?

I have a 72 911. This is what is in it engine wise. 2.7 rs p's and c's. Modified t cams-why, for auto crossing. Modified inj. pump. Rebuilt ignition, but not updated or modified. K&N fiter. Crane coil,Magnecore 10mm wires. Stock heat exchangers. Muffler is stock but, I'm buiding a new one myself and will post if it works. By the way this car is stripped down and about to be painted. So, what else can be done to this car engine wise to give it a little more power. I know there are allot of performance guru's out there that know little tricks that I don't. These mfi cars are tricky so any help would be great
Thanks

Isolon,

You don't mention wheels and tires, or flares ... I would hope you are putting SC/Carrera flares on, along with the painting. With 6 x 15 Fuchs, you could run 225/50ZR-15 tires on the rear, and that would shorten your gearing a bit. If you go with flares and large 16" Fuchs or similar wheels, Y ou can go with 245/45ZR-16s.

I have the feeling anything much more to the engine gets expensive, as tear-down and cams/head work, and more injection pump work would be needed. I'm not sure I understand your decision to not update to full RS 2.7 specs on the engine, because that engine was known for a very healthy torque curve above 2500 rpm! My recommendation would be to go with GE-60 cams, Jerry Woods' sport spring set and Titanium retainers, but that gets expensive from where you are now!

My own feeling is that transaxle work is the next order of business, with 'Airport' gearing being the most appropriate, requiring revisions in 2nd thru 5th gears, winding up with a 5th gear around 1:1 ... whether it is 1.04, 1:1, 1.08, or 0.96 is a flexible option. A minimal cost version would be: 1st-3.18 (11:35), 2nd- 2.0 (16:32), 3rd - 1.6 (20:32), 4th - 1.26 (23:29), 5th - 1.04 (25:26). A ZF or Quaife limited slip differential should be fitted at the same time as any revisions.
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Warren Hall
1973 911S Targa

[This message has been edited by Early_S_Man (edited 04-03-2001).]

Hey Warren in my quest to learn somthing new about Porsche today,why do they call those gear sets"airport gears".I just bought a new tranny for my S with lsd with close ratio 4and 5 gears..

At one time after WW II, there were many air bases closed due to cutbacks, typical of bad thinking politicians after major wars, and many were put to use in ways that could be very flexible, depending on the local promoters and politicians. Some were put to use for racing the growing 'sports cars' of the day in the late '40s and early '50s. Such was the case in Sebring, Florida, and it is the only one that survived into the '60s and got major sanctioned professional events. World-Championship sports-car racing, such as those dominated by Cobras and Ferraris ... were also competed in by Porsches in the 'lower-displacement' classes.

Because Porsches since the early '50s had interchangeable gears in both 356 and 550 Spyders/RS 60 series cars, special gear combinations were developed, and standardized by category of race track, including a 'standardized' series of names for the new 904 race car in 1964 (originally intended to use both 901 engine and gearbox) ... 'High-Speed,' which included Le Mans, and Spa race tracks, 'Nurburgring,' which was similar to high speed, but had a slightly lower 5th gear for slightly slower race tracks, 'Airport,' for even slower tracks like Sebring, and finally, the 'Hillclimb' set for the specialty work at speeds not much over 100 mph! The approximate top speeds for the above sets of gears ranged from 175 mph down to about 110 mph in the 904 ... or 911 with the gearboxes listed in the '69-'71 spec book!

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Warren Hall
1973 911S Targa

Back to the question at hand. I would
ask, what do you have for intake stacks,
intake flapper size, exhaust and intake port size on your heads? If you got a T engine MFI configuration with RS P/C and pump,
you got be neutering down your engine.
You have to know what is there first.
Your explanation only covered half or
so of the needed components to get the
most out of a 2.7 RS MFI engine.

Bill
T-->S

Stock heads, stock intakes. Was told once to install intakes from a sportomatic if i could find which i could not. The car runs great. Incredible amounts of torque with these cams. No problem spinning the tires in first and second without slipping the clucth. This is with kuhmo tires in the rear. The power curve is from 1500-4200, but that's it. The engine drops off after that. Don't want to tear down the engine again. Looking for any top end add-ons. What about distributors and the way they are curved. Would i be better off with one from an e engine or are they the same as the t.

Isolon,

All of the '72-'73 T, E, S distributors have the same advance curve, only the rev-limiter rotors are different. The RS 2.7 distributor has a more aggressive advance curve, but it wouldn't be much help with your cams!

About the only thing you can do is reset your cam timing to the most retarded (lowest lift setting) at TDC overlap. That would help the top end a bit ... but don't expect much!

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Warren Hall
1973 911S Targa

Thanks to all for your help. Have messed with the timing like crazy. When i autocross, i advance it. When street drive,I retard it.

I love the way the narrow body looks therefore i'm not flaring it. Believe me i thought about it long and hard. Also don't want to mess with the class that i run in. If i went to the wide body, there would be no way i could keep up with the people and their machines in that class. I will keep the tranny upgrade specs. My tranny has about 1-2yrs left. Sounds like a great upgrade.