924Board.org

Mark W · Joined: 05 Feb 2006 Posts: 3 Location: Sussex UK

I have an '82 924 NA that I intend to Megasquirt. Has anyboby sucessfully fitted the Bosch EFI type injectors in place of the K-jetronic ones.
It looks as if the injector can be made to fit if I modify or make new threaded inserts for the head.

It worries me though, that the hole into the inlet port is quite small and the spray pattern from the injector may impinge on it and upset things.

Is this a problem, or am I worrying over nothing??

Mark

ESC944 · Joined: 21 May 2004 Posts: 747 Location: FL

Mark their is information on this subject, do a search, plenty of guys doing the MS thing.

Also a few directions you can go with the injectors. You can relocate them to the intake, you can use and adapter in the CIS location, thier was even a recent thread/post I forget which about the o-ring size and fitment.

endwrench · Joined: 07 Dec 2002 Posts: 1631 Location: Victor, Montana

I make fuel rails and modified inserts for the guys on this side of the pond so yes it can be done. I just bore the bottem half of the insert large enough for a press in metal sleeve to seal the bottem o-ring. There is "almost" enough meat in the injector to use without the sleeve but production tolerences leave some out of round and too big. You also need to bore the top larger to fit the body of the injector.

The injector path isn't "ideal" but for a street application you will never be able to tell. Some injectors have a more "pencil" like spray pattern and would be better suited for the 924 but I wouldn't sweat finding just the right ones. I've had 2 different sets in mine with no noticable difference I would attribute to spray patteren.

Todd
_________________
'79 924NA. Rebuilt 9.5:1, MSDS header, Mega Squirt Injection, MJLJ-EDIS Ignition, 1.6L Whipple Charger and Intercooler, 10lbs Boost, 944 Trans, Custom HD Clutch.
"simsport" said....superchargers are better than turbos its official!....

macBdog · Posted: Mon Feb 06, 2006 4:16 pm Post subject:

Hey how much for a set of the inserts for my 931?
_________________
1979 931 with a 350 chev
1973 911E with EFI

endwrench · Joined: 07 Dec 2002 Posts: 1631 Location: Victor, Montana

macBdog, I charge $30 plus shipping. It may be better to mod your own. I don't have any in stock at the moment. I need to order some more. This is what you would get:

Todd

crazyinkc · Joined: 10 Nov 2002 Posts: 226 Location: Olathe KS

We just got done doing a Megasquirt I on a 931. We tried some injectors from a 350TPI my freind had and I don't know if it was a bad injector or the pattern getting distorted but, it ran awful until it hit about 2.5K. They were 26lbs injectors. We swapped in 22lbs SAAB injectors and it runs pretty good now but I think it needs bigger injectors since it seems to fall off abit around 4K. The SAAB injectors have an extended tip which my help the pattern. Now I need to finish my N/A Megasquirt setup but I just bought an 87 924S on Saturday and seem to have lost some interest in my 77

. Todd does great work and the fuel rails and inserts for both projects were bought from him.

Keaton · Joined: 02 Jan 2006 Posts: 261 Location: 85202

if you want to put more fuel into the motor you need to lower the pressure. and to put less fuel in you increase the pressure. when you swaped the injector from 26lbs to 22lbs you uped the pressure

crazyinkc · Joined: 10 Nov 2002 Posts: 226 Location: Olathe KS

Yea, he is running a Dodge regulator off a 2.2 turbo we found in the yard. He is going to pick up an adjustable regulator sometime but all the projects seem to put it on the back burner. I do not know what the 26lbs injectors were rated at what pressure but the 22's seem to do good but I think his regulator sucks. The 22's should be good for about 150hp.

fiat22turbo · Joined: 18 Jan 2006 Posts: 4040 Location: Portland, OR

Um, excuse me for being late to the party, but don't you have control over the length of time the injector is held open? Wouldn't that then mean that you should be able to tune the pulsewidth such that you could get them to work?

BTW, the Dodge 2.2 turbo regulator is vacuum referenced, so if you are running 0 inches of vacuum it will be providing 55psi. At 10psi of positive pressure to the regulator, you will get 65psi of fuel pressure. Alternatively, when the engine is under vacuum you will get less pressure. If you search around, you'll find a page on modifying a Bosch regulator from a Chrysler 2.2 turbo into an adjustable unit. Others have also just crushed the device a little to up the base pressure as well.

Just some thoughts, please carry on

sequential · Joined: 18 Nov 2005 Posts: 500 Location: BANNED

endwrench · Joined: 07 Dec 2002 Posts: 1631 Location: Victor, Montana

First, sorry for hi-jacking this thread

Second, fiat22turbo and sequential are correct. As long as the injectors are big enough you should be able to tune it. You don't need to play with different pressures. From my limited tuning of these motors I can tell you they like more fuel than some. Atleast with the NA head. They also do not like too much fuel. I fought some pretty terrible low rpm bucking on mine untill I realized it was just too rich. I kept playing with the AE tables and it did nothing! I know it is boring but I found out the hardway, it is best to follow the tuning procedure outlined in the Mega Manual to a T. It works very well.

If you were running 60lb injectors and it ran better with 22's I might say you're on to something. 26lbs is actually too small for your application. I am running 24's and have run out of injector already at 3lbs of boost!

Todd
_________________
'79 924NA. Rebuilt 9.5:1, MSDS header, Mega Squirt Injection, MJLJ-EDIS Ignition, 1.6L Whipple Charger and Intercooler, 10lbs Boost, 944 Trans, Custom HD Clutch.
"simsport" said....superchargers are better than turbos its official!....

fiat22turbo · Joined: 18 Jan 2006 Posts: 4040 Location: Portland, OR

The 2.2 non-cross flow SOHC turbo motors use 33lb/hr injectors stock for the 150hp turbo non-intercooled 9psi motors. The 175hp intercooled 2.2L 12psi and later 150hp 2.5L non-intercooled 11psi motors used the same 36lb/hr injectors.

So its just a matter of tuning.

BTW, those stock 36lb injectors have worked to around 250hp when tuned properly, though they were using a lot of fuel pressure to accomplish that along with looooong pulsewidths

I'm hoping to start my megasquirt install on the 924 pretty soon. (got some bills to pay and a bunch of clean up work to do to the car first)

sequential · Joined: 18 Nov 2005 Posts: 500 Location: BANNED

USE MIN. 40 LBS INJ FOR TURBO APPLICATION. Since you guys like to raid junk yrd engines for injectors look at mitsubishi eclipse, 944t stock injectors. these are good for 300 bhp.
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928 gts prototype
baby blue engine block
steam in 1,2,3,4 sometimes
cold star issues while on stands
112 whp with new 4 valve head and MIS 2

Keaton · Joined: 02 Jan 2006 Posts: 261 Location: 85202

ok i think some of us are talking about EFI injector and CIS injectors.
EFI injectors: more fuel pressure, more fuel.
CIS injectors: less pressure, more fuel.

and the pound ratings are fuel PSI for atomizing properaly.

crazyinkc · Joined: 10 Nov 2002 Posts: 226 Location: Olathe KS

Thanks for the info guys. We have a set of 32's out of the Dodge we got the regulator from but they look nasty so Craig was going to send them in for cleaning and calibration sometime. I will look for 40's next time I go to the yard. They usually give them to me when I buy parts for my daughters car.