I just bought a 1973 914 1.7L (with 31k actual miles) that is set up with dual weber idf 40 carbs and a 009 distributor. I'm not sure if the engine is totally stock but it does seem to pull well...but I have a very flat spot/acceleration hesitation until about 3,000 rpm's.

Does anyone have experience running a vacuum advance with the dual idfs? If so has it helped the flat response under 3k? Any help will be greatly appreciated.

By the way, this is my third 914 but the first in the last 35 years.

That's my setup, but my vac advance dizzy is not an 009 (it's a different unit off a '74). Everything I've read here seems to suggest that the flat spot is a very common trait of that dizzy, get rid of that dizzy, and you'll lose the flat spot. Originally my car had the 009, and I had the same issue as you (and everybody else with an 009)

Get the SVDA dizzy from John at aircooled.net. I installed that dizzy on my 1973 2.0 with dual Weber 40's and it ran great. You can T the vac lines to the vac ports on the carbs.

IIRC the factory 1.8 distributor is also a good option

I run one from a 1.7 but don't have the vacuum hooked up. Fixed the dreaded 009 flat spot. Runs great.

Then your essentially running a 009.

Sorry, but that is incorrect. An 009 has a completely different advance curve. The 1.7, or preferably 1.8 dizzy is apparently the best choice to run without the advance hooked up.

Made no mention of advance curve, but yes they are different but not by much and it's still centrifugal only.

I have a SVDA dizzy from Hot Spark that was suppose to overcome the flat spot but it is still there. Thinking about sending it back and going with the 009.

Mike,
The 009 will probably make it worse. The advance on the 009 doesn't come in till way too high in the rev range. But I'll let the Cap'n, Racer Chris, rhodyguy and others who know this well chime in and give the definitive. The 009 was designed for engines intended for industrial use and as such, it's advance is constant and again, comes in at higher RPMs.

I get that George. I guess I really meant to say I was so disappointed with the SVDA that it would make me go back to the 009 as bad as it is! But that really did not come across that way.

Yeah I haven't seen a lot of difference either with the SVDA. Most have recommended going back to a stock 1.7 or 1.8 dizzy, particularly the 1.8 D-jet version.

I thought all 1.8L engines were L-jet?

If you do go back to the 009 buy it from Aircooled.net. They sell a North American made one that is comparable to the old German made 009.

There is your reason: Hotspark

They're junk. You'd have been better of with a Pertronix SVDA.

Doh! Sorry. I meant L-Jet. 1.8 L-Jet. The 1.8 L-Jet dizzy is the one that is supposedly the best fit for a car converted over to carbs.

Points replacement modules can't make up for the lack of proper advance. The flat spot has nothing to do with Hotspark, Compufire, Pertronix, etc. It's the lack of a proper amount of advance when the engine sees load. Believe what you wish, but it's been debated time and time again here, and that is the consensus.

There are different 1.8 units. (All of them l-jet). One is best. I don't have the numbers at the moment.