Real world power out of 3.0 vs. 2.7

I am rapidly approaching the point that I must decide between building my 1976 2.7 or going with a 3.0

I have talked to several engine builders and really can't seperate their sales pitch from the real world.

240 HP is my goal for either motor and I want to use Carbs. MAKINUI makes an excellent copy of the Weber's that are not only easier to tune, but also have better flow characteristics. MFI is cost prohibitive and CIS just wont do what I want...

The 2.7 needs quite a few extra ($) things done in the machine shop that the 3.0 does not need. It also seems that the 3.0 SC engine is far more reliable and also has that precious .3 extra liter displacment.

Is is true for PORSCHE's that there is no substitute for cubic inches???

I would like to hear from a few with built up (more that stock power) 2.7's and 3.0's How do they drive, and how long lived are they?

Thanks very much for your opinions!

[This message has been edited by VIPRKLR (edited 10-21-2000).]

I doubt that you could rebuild the 2.7 for less money than what you could buy a used 3.0 for. If originallity doesn't matter go for the 3.0 and sell the 2.7 for parts. Use the extra money for carbs,backdated exhaust and more aggressive cams.

Bobby

PS. I think 240hp may be a little on the optimistic side for either motor. 210-220 is a little more realistic.

[This message has been edited by Bobboloo (edited 10-21-2000).]

Look at Bruce Anderson's Performance book...the best thing to do...I think (I have an 3.0SC)

Get a 3.0SC, replace the pistons and heads while you are there, 3.2L, agressive cams, Webers, SSI, he says (i think) 270 for that set up...those are my plans...

240 hp can be made with a 2.7. If you know what you are doing.take a 2.7rs spec motor and port and flow .Goodluck it will take a month just to get the ports done

If you compare the engines w/o any modification, the 3.0 is the choice.
I've driven a car with both engines (the same car, a '76 targa !)-whow, what a difference!

Jens

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IMHO bu the 3.0 SC motor and don't look back!

Randy Jones
1971 911 (3.0 SC engine)

I've owned them both (74 911 2.7 & 82 911SC 3.0).

I bought the 2.7 with 30K miles and it started leaking oil thru the valve guides at 60K. Finally exploded doing 125mph when one of the valves wobbled bad enough to stick open, piston hit it on the next upstroke, exploded and took the finned casing with it. In a split second it had destroyed one entire piston, sleeve, wrist pin, rings, et all leaving just that incredibly strong connecting rod to proceed to enlarge the whole in the magnesium case. Spent $5000 in parts and machine shop work to put it all back together including new dilavar studs, etc. Later it developed more problems and I was never happy with it. To top it off the 74 was the least troubled 2.7 --- the 75 to 77s had those thermal reactors for exhaust and usually turned your engine into a Chernobyl nuclear reactor meltdown (heat-wise) without the radiation.

The 3.0 Porsche I bought from somebody who never changed the oil, allowed the oil lines to deteriorate to the point of my having 8 oil line leaks to fix (I replaced practically all of them including the thermostat), the plug wires are falling apart, the vacuum advance had a leak that was patched with silicone, some vacuum lines weren't plugged into anywhere, it backfired like crazy because the rich/lean mixture was way off, the timing was off, and it had about 130k miles on it. I've put another 25k miles on it --- but the basic engine it self? --- goes like a bat out of hell --- solid as a rock, despite incredible mistreatment by the previous (idiot) owner(s)!

I think you can guess my opinion on which way you should go!

Well, that certainly sheds some light on this topic - thanks for the input!

Anyone else care to comment on this?

If I put Webers or Makuni's on 3.0, how much power do you think I can get and still maintain reliability and streetability? The car is very light as cars go, so super high output is not necessary.

VIPRKLR

Do you have more info on the Makinui carbs? (Not Mikuni sp?, like on Japanese motorbikes?).

Either way - any internet resource on the Weber equivalents?

Thanks!

Cam

I'll look into it tomorrow...

It is spelled "Mikuni" : )

I have them on my IMSA car they are a hands down superior unit to Webers. The make most Weber modles, so I would be very suprised if they did not make one for the 911.

250 H.P. is very possable with a 3.0 SC motor, and that is with cams that will idle and be reasonable on the street, using PMO 40mm carbs, SSI's, a sport muffler and 9.8:1 compression pistons. A little wilder with exhaust and 3.2 Carrera heads 260-270 is possable.

Randy Jones
1971 911