The low down on carbs

[rdane]

I bought PMOs and returned them. Just couldn't make that jump. Never had carbs but they look so "purty" in the engine bay. Looking for that throttle response but not 8 miles per gallon.

I have seen Randy Jone's comments on PMOs for a road car, after he dumped his off Iris at the end of his first driving season.

Come on guys tell us your carb stories, good and bad.

I remember the first PCA tour when a hefty percentage of the guys had to make a gas stop in what I thought was awful short order. Carbs and bad milage is my guess now.

We all ended up in the same place, in about the same amount of time, so are they worth it on a "fun" street car?

The PMO web site makes them look aweful tempting again. Going as far to say, "the CIS cams are great for carbs"!

It is a specific built 3.4 with 9.8:1 Max Moritz CIS P&Cs and 20/21 cams, none of which is going to change if I go to carbs.

[Steve@Rennsport]

Hi:

Everyone has opinions and experiences so I'd simply offer my own,..

Over the past 27 years, I've had excellent and positive experiences with carbs (Webers & PMO's) on Porsche motors. No problems at all.

That said, I've seen hundreds of cars with totally screwed up carbs and poorly setup installations-adjustments-calibrations that would drive anyone to drink,... No wonder carburetors have such mixed opinions and generate such polarized views. Carbs, just like MFI, doesn't suffer fools,....

IMHO, the problems people have with them is a failure to pay attention to the details and suffer the result of either incorrect fuel pressure/volume, incorrect float level and wrong configuration-jetting.

The 3-bbl carbs found on 911's were never designed nor intended for maximum fuel economy; best power and throttle response were the overiding criteria and they do that job quite nicely.

I think one chooses what is most important and follow that lead. Carbs will never deliver the fuel efficiency of any CIS or EFI system but they are very simple and reliable devices that make VERY good HP and torque. PMO's are FAR better than Webers in every respect, too.

That's my story,....

[Wayne 962]

I agree with Steve. However, I would like to add that for the cost of carbs, you can probably get yourself into a TEC-3 system (for only a few bucks more). The TEC-3 is nice because you can take it from car to car (it's universal). In addition, nothing beats engine management for throttle response and overall power. However, you're engine compartment is not going to look stock or "retro."

Also, the main advantage (one of them) of going with carbs (or any individual throttle-body system like MFI) is that you can run a very hot cam in there and you don't have to worry about fuel reversion or interaction between the cylinders within the fuel injection system.

-Wayne

[jgparker]

My one gripe with Webers is the idle jets are so small they clog every once in a while, even with double filters. At least the problem is easy to diagnose, and easy to fix.

Does the price for the tec-3 system include throttle bodies, manifolds, air cleaner etc?

Thanks,

JP

[Steve@Rennsport]

JP:

You are correct although I will tell you that if you have clean fuel and air, they stay clear for many many years.

That means a spotless, rust-free tank, really good fuel filtering, and effective aircleaners.

This would apply to carbs, MFI, and any EFI system you might use,....

[Wayne 962]

No, the TEC-3 system with a Carrera 3.2-type manifold setup would run around $2500 I think, which I think is roughly the cost of the PMOs? Individual throttle bodies from a place like TWM are super-expensive, costing something like $3K for the set retail.

-Wayne