Pelican Parts Forums - Assembling new engine should I go MFI, Weber or PMO ?

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- - Assembling new engine should I go MFI, Weber or PMO ? (http://forums.pelicanparts.com/porsche-911-technical-forum/7017-assembling-new-engine-should-i-go-mfi-weber-pmo.html)

I'd go with the MFI. Even in a non-standard set up they can work very well. I have MFI on my 2.5l (short stroke), using TWM throttle bodies and it just screems!

http://www.pelicanparts.com/ultimate.../engineout.jpg

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Mike
See my cars

Thanks all for your input. At this point I'll stick with the MFI and see how they perform. I've ordered a dual in/dual out dansk to see how that performs. Other that obvious stumbling or rough idle symptoms, how will I know if I need to "tweak" the MFI to get the most out of my planned 10.5 CR and twin plug setup? Or can I hope for a bolt on and go setup? Ha ha ha. My last bolt on and go was my BK harness guide bar. I had to cut off 1" to make the bar fit into my early 911.

Thanks again everyone. This list is great!

Regards,
Rick

KAT....I have no background on your set-up, but I would take the sensitivity of the 911 seriously, unless there is a bulletproof program to follow. In MHO I would install a exhaust temp. sender immediately, before expermenting with dialing in the beast. Don't let your meat loaf........Ron

DAVID......I took notice that you had a 2.7 w/E-cam, Webers, etc. I plan on that in my 2.7. Carbs are in closet, cams as soon as smog is over with. My 911 is 77 w/stock gearing. Question, how was torque on highway from 3000 to 4200 rpm? Did it burn clean, or dirty spark plugs. What spark plugs did you use? How long did plugs last? I'm looking for performance on cross-country rides...........Ron

Quote:

<font face="Verdana, Arial" size="2">Originally posted by old_porsche:
I have always like the MFI. It, along with the proper exhaust, has the performance. I have had personal experience with both carbs (2.7 euro piston, e-cam, webbers) and approximatey the same motor in MFI. As to the MFI warm up feature, it was replaced with a manual choke handle set up.

With the market for carbs being what it is you may want to invest in a set-up to try it out. It's not like you can't sell them later.

I just wouldn't dump the MFI right away. There are a lot of very successful setups out there.

Good luck,
David Duffield </font>

Ron,

You can't use the 2.7 CIS pistons with 'E' or Solex cams ('E' engines used two different cams over the life of the three different production engines -- 2.0, 2.2, and 2.4) ... because of the lift, and not enough clearance with those funny 'humped' CIS pistons!

So, you are faced with either getting aftermarket pistons like JE with valve clearance notch option, or the 'Euro' RS 2.7 piston & cylinder sets. For the money, if yours are Nikasil cylinders already, the JE 9.5:1 forged pistons are the way to go.

Personally, I would recommend the GE-60 cams with a 2.7 Weber conversion, but the Solex cams are great, too, as Jack McAllister will testify ... Ferocious above 5000 rpm!!! And, with forged pistons ... 7300 rpm redline with either cam choice!

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Warren Hall
1973 911S Targa
1992 Dodge Dakota 5.2 4X4 parts hauler

maybe it would be a good idea to start with the "stock" heat exchanger and Leistritz muffler setup. at least you know you are starting with a known baseline. it's just i know of at least 1 person that after exhausting much time and effort ended up with the stock Leistritz muffler.

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Carlo
http://bigblue111c.tripod.com/dec2000/