Megasquirt Progress, Main Board complete Options

[yarin]

Tonight I have completed building the main board for my MS II V.3.0 system. Thanks to those that have helped out. Once i'm all finished I will definitely post a complete "How To MegaSquirt a 914" website with pics and step by step. So far i'm still at the desk level. I've got 2.0 injection parts on the way.

I'll be using the following:

stock injectors
GM air temp sensor
stock fuel pump
summit racing manifold referenced fuel pressure regulator
stock injectors (i think 2.0s are on the way)
stock plenum / runners
stock CHT
MS Relay Board
Innovative WB02
High Current ignition driver
Stock dizzy with pertronix (hall sensor)
Stock Bosch Blue Coil
PWM Low impedence injector driver (no resistors)
Stock Cold start Valve (plan so far)
Stock throttle body with some junkyard TPS

Here is a pic of my board, took me a few hours a night every night this week. I took my time, double checked everything. So far so good!

I don't expect to have the system in the car for at least another month. I'm converting from carbs so I want to install steel fuel lines and clean some stuff up.

I'll be sure to post progress in the forums. (IMG:http://www.914world.com/bbs2/html/emoticons/smilie_pokal.gif)

[lapuwali]

QUOTE (Jeff Nelson @ Feb 1 2006, 05:15 PM)

Are the specified components in MS spec'd for the temperature range experienced in the stock ECU location of a 914 engine bay? If so then that is a nice place to put it. I've got a 2.0 and have some concerns regarding the use of the 2.0 injectors. One is the excessive flow capability and getting a good idle and the other is the electrical connection. I understand that the L-jet injectors have a superior connector. Do they work with the D-jet mounting components, that is the part that clamps the injector? What would be a specific L-jet injector that would flow more like the 1.7 D-jet parts but have the better connector? Would the 1.8 Subaru injector mount ok with the stock D-jet parts? What is the connector on the Subaru part? There is a good page at SDS showing a number of different injector styles: http://www.sdsefi.com/injectors.htm (This page indicates that the Subaru connector is not the one used on an L-jet injector.)

The MS processor (HC08GP32) is a 70dC part, and so is marginal in some places on the 914 that get pretty hot. The rear trunk, for example, appears to get too hot on a hot day. The front of the engine bay, from previous measurements, doesn't seem to get much more than 10dC above ambient, so unless you're driving across Death Valley in mid-summer at high noon, you're OK. The MSII processor (HC12) is a 125dC part, so it's plenty safe even sitting on the engine itself.

L-Jet injector connectors work with D-Jet injectors. The D-Jet injector connector is pretty bad, just slotting into the outer plastic bit fairly loosely and depending on a rubber shroud to hold it in place. The L-Jet connector has a plastic surround that covers the electrical connection, and has a wire clip to hold it in place. You may have to do a bit of cutting on the L-Jet connector surround to get it to fit perfectly, but it will fit.

L-Jet was used on a zillion cars, so find a car with an approximately similar cylinder size that was made in the early to mid 80s, which increases the chance of it using a hose-barb fuel connection, instead of a fuel rail. I know some Italian cars (V6 Alfas) used the hose-barb L-Jet injectors throughout the 1980s, and the 2.5 V6s have roughly the same cylinder size as a 1.7 four. The SDS site also has a handy chart showing flow rates v. max horsepower to give you a rough idea of sizing. The 914 1.8 used L-Jet with what's otherwise a 1.7 plenum and runners, so "L-Jet" injectors, at least some of them, are identical to D-Jet injectors.

I wouldn't be TOO hung up on the large size of the 2.0 injectors. If Dave has gotten in running with the fixed pressure FPR (and I have no doubt that he has), then it will work. You may find it advantageous to use the hi-res code, or MSII, so you get better than 0.1ms injector timing resolution. 0.01ms should be good enough, and I think the hi-res code did 0.001ms or better. MSII does even better still, as I recall. I'm using 1.7 injectors because I have them, and they'll work.

There's more than one kind of Subaru injector. Searching for posts by airsix will get you more detail. He's using injectors off a 1.8 Subaru on his turbo 1.7, and I'm pretty sure he's using a stock 1.7 intake setup. He'll be able to confirm this.