Brucechas

Greetings all,

I'm wondering if anyone has installed PMO webers on a 3.0 motor? I would like to know overall results, dependability etc.

Thanking you in advance,

Bruce

Steve Weiner-Rennsport Systems

Hi Bruce:

Yessir, dozens of these conversions, to date,..... We are PMO Dealers.

These things really increase throttle response as well as overall torque but need to be used with a SSI-Sport muffler exhaust to make it worthwhile.

As long as one fully understands how to set these up and is willing to invest the time, its really neat!

Doug&Julie

Now here's a question you probably don't get when asking about putting carbs on a 3.0....how is the mileage?

Steve Weiner-Rennsport Systems

Well Doug,....mileage is all about how they are setup and jetted as well as what your right foot position is,....

They CAN do very well.

Wachuko

Care to share a rough estimate on what the conversion goes for? Are the ones to use the 46mm???

46mm around US$2700 + US$600 for the installation kit + ???

Thanks you. Something I have in my wish list and would like to know how much I have to budget for....

Steve Weiner-Rennsport Systems

Jaime:

I tailor the carburetor size and configuration to each particular engine's displacement, cams, compression and how its being used.

These run $ 3300 for the complete 46mm kit.

r911

yes, plus labor to install and tune

BUT, if you really want what the carbs can offer it is MUCH more expensive: you need new cams, new pistons + labor. But you then get a real powerhouse.

Brucechas

Thanks a million for the great info on the PMO's, Steve...I emailed you at your shop and am looking forward to working with you.

Thanks again,

Bruce

Doug&Julie

Good to hear. I'm more of a "use it as a daily-ish driver but love to get on it once in a while" kind of 911 owner. So mileage is kinda important to me. I just don't want to get 12mpg in a car I'll drive frequently.

That is if I can't sell it.

Thanks for the info!

Wachuko

Thank you for the information.

TonyG

Done PMO's quite a few times.

Great carbs. You need to really understand how to get the cross bar linkage geometry correct. I wish Richard would mold in the bosses for the cross bar into the carb bodies like the Porsche MFI. This would go a LONG way towards taking a good thing and making it great.


Also, you need to have a good understanding of carb setup & calibration.


Mileage > Sucks (it ain't ever gonna get 20MPG)
Performance > Excellent
Drivability > Good (depends on your knowledge of carb calibration)

No cold start/choke feature. Not a problem in Southern California... but could be a problem elsewhere.


TonyG

joetiii

I've got PMO 40s on my stock 3.0 SC motor with SSI's and an M&K 2 in 1 out. As mentioned above, its got great throttle response.

I'm curious Steve, how the carbs make for better torque???

I plan on updating my '82 engine with new cams next season and am thinking about how extreme a profile I should run.

I was under the impression that a warmed up street / track car would do fine with 40s while 46s should be considered for higher compression / more overlap cams. No?

TonyG

joetiii

I had a rebuilt '82 (small port) SC engine, bone stock except SSI exhaust, M&K 2 in/2 out muffler, Web Cam 20/21 cams, and PMO 40mm carbs.

Made 199.xxx HP to the rear wheels SAE corrected on a dynojet.

Also, you are better off using 40mm carbs on the small port heads, as you will be using either a 34mm or 36mm venturi.

Here's the dyno (with 34mm venturies):




TonyG

Steve Weiner-Rennsport Systems

Hi Joe:

A simplified answer is that PMO's one-throttle-per-cylinder offers 6 short columns of air for each cylinder to accelerate when the intake valves open, compared to a common-plenum intake with one throttle plate serving all 6 cylinders. Intake velocity in each stack is much faster than the common-plenum systems, depending on venturi diameters.

I will also mention that we've done some common-plenum intakes using the resonance chamber and added individual throttle butterflies (ITB's) to each runner instead of the big single throttle and the results are simply amazing. The throttle response just as good as carbs or MFI much a much flatter torque curve. Of course, we use Engine Management to tune these systems.

Camshaft limitations in your motor lie with your stock pistons which cannot tolerate much valve lift. 964 or 20/21 cams are about it unless you install pistons with double valve reliefs. I'm no fan of the common practice of machining stock pistons for more clearance.

SeattlePorsche

Tony,

Thanks for posting your dyno data. I like the relatively tall and flat torque curve with your 20/21's. Did you have special compression ratio P/C's or stock 3.0 CIS ones? (if so, are they US or Euro?)

By the way, a belated thanks for the sun visors. I had to go to a funeral about the time I got them and I wasn't much in the writing mood. But anyways, much thanks. (Where have you been lately?)