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-   -   CIS to Carbs? (http://forums.pelicanparts.com/911-engine-rebuilding-forum/552501-cis-carbs.html)

Walt Fricke 10-29-2010 07:52 PM

I just switched from a carbureted 2.8 race motor to EFI and ITB. The throttle response was amazing. Good for a couple of seconds on the track. But track tuning is a lot simpler than street tuning, as you really don't care about part throttle or idle.

A mag cased 2.7 is not, however, the engine I'd want to fuss around with hot rodding. Longevity compromised with stock power as it is. CIS is a pretty nice street system. Its complexity is at least easier to understand to some of us than a computer controlled system. It can be made to run just fine.

Walt

safe 10-30-2010 12:49 AM

EFI is sweet with endless tunability, but I think its a lot easier than carb and CIS. My belief is that initial tuning of an EFI system on a rolling road by a professional is mandatory.
A good tuner will have the system running at 99% in 4-6 hours.

Back to the mag case CIS to carb with e-cams. I just want a sweet running street engine with good throttle response and a bit more power than its original 165-175hp.

red 2.7 11-02-2010 11:03 AM

carbs?
 
I have a very sweet running mag case 2.7 1977 with PMO 40's e cams barry hershon recurved dizzy ssi's and m&k 2 in 2 out. MSD 6al. Idles beautifully and pulls strong up to the redline and beyond if I let it. I have a 6.5k limiter. I could not recommend it mor e it's super. I only had to change idle jets from 55's to 60's to remove a slight flat spot at transition. It's a little loud but i love it. I had Webers before the PMO's and they were sold for $1500 and the new PMO's cost 3K I think. My pro Porsche mechanic's butt dyno estimates 200 to 210 horses. good luck with your project.

wally , Montreal

safe 11-02-2010 11:11 AM

Quote:

Originally Posted by red 2.7 (Post 5650733)
I have a very sweet running mag case 2.7 1977 with PMO 40's e cams barry hershon recurved dizzy ssi's and m&k 2 in 2 out. MSD 6al. Idles beautifully and pulls strong up to the redline and beyond if I let it. I have a 6.5k limiter. I could not recommend it mor e it's super. I only had to change idle jets from 55's to 60's to remove a slight flat spot at transition. It's a little loud but i love it. I had Webers before the PMO's and they were sold for $1500 and the new PMO's cost 3K I think. My pro Porsche mechanic's butt dyno estimates 200 to 210 horses. good luck with your project.

wally , Montreal

What pistons do you have?

al lkosmal 11-06-2010 06:31 PM

Here is my EFI ITB setup......

http://forums.pelicanparts.com/porsche-911-technical-forum/573869-my-triumph-speed-triple-project-update.html

JmuRiz 01-05-2011 01:08 PM

Quote:

Originally Posted by red 2.7 (Post 5650733)
I have a very sweet running mag case 2.7 1977 with PMO 40's e cams barry hershon recurved dizzy ssi's and m&k 2 in 2 out. MSD 6al. Idles beautifully and pulls strong up to the redline and beyond if I let it. I have a 6.5k limiter. I could not recommend it mor e it's super. I only had to change idle jets from 55's to 60's to remove a slight flat spot at transition. It's a little loud but i love it. I had Webers before the PMO's and they were sold for $1500 and the new PMO's cost 3K I think. My pro Porsche mechanic's butt dyno estimates 200 to 210 horses. good luck with your project.

wally , Montreal

Sorry to bring up an old post, but I'm in the process of getting parts to convert to carbs as well:

When you all do an MSD 6al ignition do you also convert the dizzy to remove the points?

Thanks,
Nathan

PS: al lkosmal - your ITB setup sure looks cool, I'll probably check into something like that at some point, just no all-inclusive kits for us newbie EFI ITB guys. If yours ends up like that I'd be all over it.

Eagledriver 01-05-2011 05:59 PM

You can use the points with the MSD. I haven't done a conversion to no points. I like the simplicity and reliability of points.

-Andy


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