Modern Injector and Higher Pressures, What improvements have you seen? Options

[Brian Mifsud]

Another thread about custom fuel rails had references to using modern high pressure injectors with associated proper manifolding.

Has anyone "converted" and how have your results been?

I'm guessing you need to consider pulse voltage, pulse duration, flow rating of injector, and line pressure as the factors to pick the right injectors.

Cleaner? Better driveability? Better mixture control?

[Mueller]

I think it has more to do with smog/cleaner burning engines than outright power increases with the modern finer-spraying injectors...smaller droplets mix better with the air so less unburnt fuel is dumped out the exhaust...

not talking about direct injection like the new Audis have....I don't see many people playing around with that fuel injection for a while (IMG:http://www.914world.com/bbs2/html/emoticons/smile.gif)

[Brian Mifsud]

I follow you Mike. My "5th" injector is either leaking, or it's getting a signal to stay open, so while I doubt I need it for "cold start" in Southern Cal, it just prompted the thought of replacement, and if there was a better way to go "while I'm in there".

Of course, if you as you say, you get a cleaner burn, that implies that I'm burning MORE of the same charge of fuel. If I get the right amount of air in the cylinder, and enough compression and swirl, I OUGHT to get more power. Better fuel economy should be a given I'd think.

Some of the Beetle engine suppliers were furnishing GM based FI systems for the TYPE I's. I'm guessing they were running at "modern" fuel pressures?

[Mark Henry]

QUOTE (Brian Mifsud @ Feb 21 2006, 10:03 PM)

Some of the Beetle engine suppliers were furnishing GM based FI systems for the TYPE I's. I'm guessing they were running at "modern" fuel pressures?

That system is the CB performance unit...not much good is ever said about it. There's at least a dozen other systems that I'd try before I'd even sniff at that one.

Higher pressure doesn't necessarily equal better power etc.

[lapuwali]

QUOTE (Brian Mifsud @ Feb 21 2006, 06:03 PM)

I follow you Mike. My "5th" injector is either leaking, or it's getting a signal to stay open, so while I doubt I need it for "cold start" in Southern Cal, it just prompted the thought of replacement, and if there was a better way to go "while I'm in there". Of course, if you as you say, you get a cleaner burn, that implies that I'm burning MORE of the same charge of fuel. If I get the right amount of air in the cylinder, and enough compression and swirl, I OUGHT to get more power. Better fuel economy should be a given I'd think. Some of the Beetle engine suppliers were furnishing GM based FI systems for the TYPE I's. I'm guessing they were running at "modern" fuel pressures?

The cold start injector is a whole different thing to the other injectors. It's not pulsed, but just turned on during cranking to spray a huge amount of fuel in to provide the very rich mixture many engines need to start when dead cold. You can get away without it as long as you don't mind cranking more to get the engine to fire.

With better atomization, you'll get the same power for less fuel, but not really more power. One doesn't necessarily follow the other. You'll also get lower emissions. You might get slightly crisper power delivery, but it's going to be subtle. This all assumes you don't do anything else, of course.

Converting to higher pressures would not be trivial, and I don't think would be justified unless you were doing a lot of other things, too.

[davec]

I used a Haltec engine management system to program the Mustang injectors. Pulse width was determind via a wide band lambda, then refined on a full chassis dyno with variable loading. The real point of fuel injection is the resulting torque curve, which is much more consistent (level) than carbs. My 2.7 has about 200lbs across the rpm band.