PMO TB and injection versus PMO carbs
 

I have a 3.0 with 964 cams, Euro P&C's and headers. I use my car for as a daily driver and a weekend fun car, with some long trips across the desert and into the mountains.. I am looking forward to some track time in the future.Like all of us, I'd like a little more hp, without breaking the bank.
My mechanic is recommending PMO carbs and bigger cams. I like the price and simplicity of carbs, but I am concerned about difficult starting, idling, frequency of adjustments and changes in elevation. In theory, I suppose PMO TB and EFI is superior, but this Board is frequently filled with owners complaining that they can't get their settings straight. I'm not interested in having a lap top as a co-pilot. Also, if I am away from home and something in the injection goes south, I'm pretty much looking for a trailer ride.
Any words of wisdom from you carb and EFI owners?

R Goodrich

81 SC
83 Euro SC (gone)
99 996 (totaled)

PMO carbs rock the house. They are the most "set and forget" carbs I've ever seen, aside from what I've put on small block chevy's (big edelbrock fan). The PMOs start decently cold, warm quickly, decent fuel economy (with proper adjustment) and flawless drivability.

The FI is better in every way for driveability, starts, and probably fuel economy. It does cost more and will require a fair bit of setup. There's at least one or two threads on this BBS regarding the setup. Those would be good reading to determine what you are getting into for setup.

angela

I have webers on my 3.0 right now. great. mileage could be better but dead dependable and easy to diagnose/fix. jetted decently they're great. I can floor it in fifth at 1500 rpm and it just pulls away, no popping sputtering, nothing. I like a fuel pressure gauge, makes easier diagnosis, likewise clear fuel filters right before the carb. cold starts are fine, give them a couple of pumps and fire it up. run it on the foot pedal for 30 secs and you're good to go. by all accounts PMO's are even better.

http://forums.pelicanparts.com/porsche-911-technical-forum/502996-3-0-dyno-day-pleasant-surprise.html

I like my PMOs.

Where do you live - how cold does it get?

I live in the deserts of AZ. Cold is only a problem on trips to the mountains, but vapor lock could be an issue in the summer.
R

Also, if I am away from home and something in the injection goes south, I'm pretty much looking for a trailer ride.

you pretty much summed it up right there. not saying anything bad about pmos in particular, but if you can't fiddle with the system to get it going again in the middle of the desert, yer screwed.

John, wouldn't that be pretty much the same with any injection system, including Motronic if there wasn't a spare box in the next little town? You have far more experience in this area than I, but other than a failed DME relay, I'm pretty certain there's not much a person can mess with if it just quits.

summer temps here are commonly in the 90-100 deg F range. phenolic spacers under the carbs an I've never had vapor lock. I should add that cold starts here mean 40 deg F plus. I don't drive the car in winter.

if the ability to fix on the fly matters, go carbs. I carry an extra fuel pump and some fuel line. figure there's not much I couldn't get going somehow, fuel-delivery wise. with a good fuel filter, there ain't much can go wrong with a carb. your ignition is much more likely to be the no-go issue.

Speaking from Colorado, most days in the spring and fall with carbs were a bear. Below freezing was almost impossible without a lot of work. In cold weather I could get them started, but without a hand throttle I had to babysit the throttle for the first 3 or 4 mins. After that it was still a good 10 mins to get a good operating temperature. ymmv.

below 32F w/carbs means lighting up a cig and wait till CHT gets to 150F before moving

at least i could easily tell if ignition or fuel is the issue and r&r on the side of the road if need be

zooming around the SW deserts and having a FI issue must suck even if you could isolate it to the FI. In a metro area a trailer ride could cost $100. If you're way out in the desert 200 miles from a shop maybe you could trade your first born for the ride?

maybe - or you could die there

one reason I went with carbs

on a cold day, you can use a heating pad to warm things up - sounds crazy but I've crammed stoves, fuel bottles, etc. into my armpits or crotch (try to reserve for hands of female companion)

Besides looking really cool, what are the added benefits of going ITB EFI over just EFI?

Mainly throttle response. Think BMW normal vs M, almost always changes to ITBs.