Questions about Rear turboing a B6 SOHC

[sketchman]

My theory is - use bigger injectors, turn down initial fuel pressure with an adjustable FPR, then use the FMU to bring it up under boost. I've never done this though.

I have also read that too low a pressure can cause problems with the injectors. However, I remember reading a project (which I can't find now to save my life) where a guy used an Arduino board to inject a little single cylinder engine, and he said that the injector worked fine even down to something like 10-12psi.

[eurotiva]

Why not just use an fmu? There's no need for bigger injectors with an fmu. The fmu makes the the injectors flow more than they are rated. I ran 10 lbs of boost for years like this

[sketchman]

If you can start at even 15psi fuel it would give you more room to boost while using a single fuel pump and keep max fuel pressure lower.

[Flyin4stroke]

Injectors are rated at 43.5 psi. Not sure how they would react at less than half the pressure. Here is a chart for 600cc

[Movin]

Why not just use an fmu? There's no need for bigger injectors with an fmu. The fmu makes the the injectors flow more than they are rated. I ran 10 lbs of boost for years like this

How much fuel pressure did you have to supply to the fmu ? Would 90 psi be enough ?

[sketchman]

There is also this. Go to bottom of page.

http://www.witchhunter.com/injectorcalc1.php

Found it. All the images are gone, but it was even lower pressure than I thought.

Only 7psi, and they still worked fine.

http://forum.arduino.cc/index.php?topic=8677.0

The pump is a Mr. Gasket 7 psi. Before installing the injector I played with the pulse width by watching the spray patern on a piece of paper. My findings were that lots of small squirts are much better then longer ones, 2ms pulses are hardly visable and 100ms pulses are like pulling the trigger on a windex bottle.

[TorqueEffect]

Isn't mega squirt a fmu. I can't afford one of those. Lol
Hence the question about swapping injectors, ecus, or vafs.

[bhazard]

Megasquirt an FMU? Lol

I suggest you break out of your cocoon and read, bud.

http://en.wikipedia.org/wiki/MegaSquirt

[bhazard]

With all the time and money you would spend trial and erroring combinations of VAF, injector, fuel pressure, rednecking it along the way you could have put together a MS kit for a few hundred and be 10x farther ahead.

[TorqueEffect]

Megasquirt an FMU? Lol

I suggest you break out of your cocoon and read, bud.

http://en.wikipedia.org/wiki/MegaSquirt

well can you blame me? Technically an ecu can be called a fmu since its main purpose is to manage fuel delivery. So I thought fmu might have been a different way of saying megasquirt.

[Movin]

Its just a fancier version of the regulator already on the fuel rail.

[TorqueEffect]

Its just a fancier version of the regulator already on the fuel rail.

Yeah, just did an eBay search. They seem to be about $100. What ratio would be best? I plan to run about 8 or 10 psi of boost, nothing more to avoid throwing rods.

[Movin]

A lot of really good ideas, but unless you have spare engines look for the guys who have everything working good and a long history of no problems. It looks like even then you have choices but at least they are good ones!

[TorqueEffect]

A lot of really good ideas, but unless you have spare engines look for the guys who have everything working good and a long history of no problems. It looks like even then you have choices but at least they are good ones!

I've got a spare engine. Just a b3 though. I know turboing old engines is a gamble. Might even buy that other b3 for $75 that someone listed for ohiostiva. Can't have too many engines when you start running boost though them lol.

[Flyin4stroke]

The boost doesn't kill the engine. Boosting for long periods of time and heat soaking the engine is what kills engines. On 8-10psi I would say you wouldn't be hindering the longevity of a stock engine. Now once you start turning that 1 knob that gives you more boost welllll then you will be putting a lot of strain on parts. More boost more pressure more heat it all goes together.