Holley EFI, Not just for American 4BBL carb replacements anymore... Options

[horizontally-opposed]

So I am hearing this is a very attractive setup for 4+ cylinder engines, and can be made to work with ITB setups for a flat six, such as PMO's. The 4BBL pricing sure is right, and it's said to be "self tuning" and a dream to work with/on.

Anyone have any experience of this, or know of a Porsche engine running it?

[Mark Henry]

You can get almost anything to work (IMG:style_emoticons/default/smile.gif)

With large duration cams and ITB's any engine is going to have vacuum issues. If you want to avoid these issues with SDS, MS or any of the other other systems you must do a single TB plenum type intake and use a cam(s) with less duration.
Jake messed with a system called Kit Carson (sp?) back in early 2000 they abandoned it and I believe the issues they were having was to do with ITB/vacuum. Jake then went with SDS largely because of my success on a single plenum application, but he to ran into ITB/vacuum issues.

You look at Porsche and all other manufactures, once they went with EFI all their systems have a single TB plenum intake and cams with less duration. This have everything to do with the poor vacuum signal and the mandate to have a smooth performance curve.

Why I take issue with Rob knocking SDS is he has no experience with PEFI other than one engine that was misconfigured to his expectations. It doesn't matter what system whether it be MS running "alpha-N" or SDS "TPS only" he would have ran into the same issue.
He never tried TPS only, in fact he refused the suggestion and he never did MS, he just gave up and sold the engine.

MS has the exact same issue, do a google search using keywords "megasquirt","ITB", "vacuum", "apha-N", "TPS only", "cam duration" and you will see this is not just an SDS issue. Go over to the Pelican parts forum and you will find most MS ITB hot cam application they have to resort to alpha-N (TPS only) programming.
This is the point I was trying to get across, it's not just SDS that has this issue, all systems do.

I ran SDS with a basicly stock D-jet single TB/plenum intake, 2.0 D-jet injectors, on both a stock 1.8 and a 2.0 with a mild scat C-25 cam, both engine ran flawlessly with none of the ITB/vacuum issues affecting the MAP sensor. Nothing spectacular as FI doesn't add HP, but you couldn't tell the difference between L-jet, D-jet or the SDS. The 2.0 I ran for about 4 years with the programer never installed after initial tuning. It behaved no differently than a stock FI system.
I have installed several systems in customers cars this way, with similar stockish engines and all have performed flawlessly.

Does the Holley have an edge on this issue?
My educated guess is no, thier test beds are LS engines that have a single TB/plenum and engines using a V8 carb manifold which is a lot like a plenum. I would go over to V8/FI forums and see if they have the same ITB/vacuum issues with aftermarket FI, my bet is they do.