CIS to EFI Conversions? - Page 7

JohnC · 10-17-2002, 08:36 AM

Injector info.

http://fiveomotorsport.com/Injector_Sets.asp#f83e

tbitz · 10-17-2002, 09:54 AM

Janus,

My project has been put on hold till winter. Once the car is parked for winter I will restart the conversion.

I picked up my injectors on ebay. I got eight 19lbs/hr injectors from a 5.0L (302ci) Ford for $15.

I think they should be big enough for a stock 3.0L. Some calculations were done on an earlier post in this thread.

I think the openings for the injectos are fairly standard, so I think they would fit on the stock 3.2L manifold too.

I can post some dimensions of the injectors from 5.0L ford (they are actually made by Bosch) and maybe Ben can compare.

Have a look at my web page(link below) I have pictures of the injectors posted.

Note: Ben has his ECU in the engine bay and hasn't had any problems. I had the ECU in the engine bay during the summer, and had it fail on a really hot day. I was only monitoring rpm and air temps at the time. I think I will be putting the ECU in the cabin, to avoid such problems.

Wrecked944 · 10-17-2002, 10:34 AM

"Assuming a BSFC of 0.55 lbs/hp/hp you get the following power based on 100% duty cycle of the injectors. I believe this assumes a fairly rich mixture.

19lbs/hr = 207Hp
25lbs/hr = 272Hp

Some of the "experts" say you shouldn't run them at 100%, but rather 85%. If you use the 85% duty cycle you end up with:

19lbs/hr = 176Hp
25lbs/hr = 231Hp"

So if one runs at less than 100%, then wouldn't the 25lbs/hr injectors be better? And yet porsche uses the 19lbs/hr model for a bigger carrera engine? I guess I am really asking a deeper question: What are the criteria for selecting a particular fuel injector model? Is it more art or more science?

CamB · CamB's Garage

I went round and round on this for different reasons. I suspect the Porsche engine is more efficient, plus don't forget you can raise the fuel pressure.

Everyone with over 250hp read me!

garrickl · garrickl's Garage

Here is a site for determining injector size and possible horsepower: http://www.rceng.com/

For those of you looking at adapting the factory DME EFI you may want to consider Split Second products for reasonably priced MAF conversions, air\fuel mixture calibrators and timing retard boxes [turbos]. They have an air\fuel calibrator that allows laptop mapping of the entire air\fuel table factory DME brain using Windows software for under $400. http://www.splitsec.com/

tbitz · 02-23-2003, 07:59 PM

My 911SC started and ran for the first time tonight under the new EFI system. The CIS is out and EFI is in. I was surprized how quickly it started and ran. The tuning fun begins now

Here is a shot of the engine bay with the engine idling. All that is missing is the air filter. I love how clutter free this engine bay is.

I'll be updating my web page within the next couple of days with the latest info.

Wrecked944 · 02-25-2003, 08:27 AM

Weeeeee !!! Congratulations !! Man, that is awesome. You have now forged ahead and pushed the technological frontier beyond its previous horizon. So far, the only documented CIS to EFI conversions have used Carrera intake manifolds...but your method will help to reduce the costs for DIY-ers...I await the website update so the knowledge can be disseminated.

Perhaps we can arrange to have you and Ben Willis awarded the "SCWDP Gold Palm for Technological Excellence".

Sadly, I must report that my own EFI conversion has been permanently postponed by an "external combustion event" (read: FIRE) that toasted my precious 911SC. She is much better now, but her new engine has carbs...so it will be a while before I can afford to do any major research into EFI...so till then I must live vicariously through you guys...

:-(

turbo6bar · 02-25-2003, 08:55 AM

Tony, I will follow your project with great interest. I am particularly interested in the driveability, economy, and power (can you get more power with EFI on a stock CIS engine).

Good job,
Jurgen

tbitz · 02-25-2003, 09:39 AM

Unfortunatly it is still very much winter here in Ottawa, Canada so it's going to be a while before this baby is on th street. I will do as much tuning as possible in the garage. This will only allow me to tune for no load conditions though.

turbo6bar: The ECU runs 'closed loop'. It uses an O2 sensor to montor the exhaust and automatically adjusts the fuel mixture. This should help improve the fuel economy.

As for more Hp, those with a sharp eye will notice the "red top" injectors (32lbs/hr). These are capable of delivering enough fuel for well over 300Hp. Can anyone guess my next project?

Mukilteo911 · 02-27-2003, 03:53 PM

how many self fabricated parts to do this conversion? From looking at your web site it looks like you need metal lathe to pull this off. I want to do the same thing I have a 2.7 CIS system in my garage and want to do this for a 2.4L engine. How much has it cost you to do it ?

Thanks

tbitz · 07:33 PM

double post, whoops

tbitz · 02-27-2003, 07:32 PM

There is really one thing that must be custom made. They are the adaptor rings that allow EFI injectors to fit in the CIS intake runners. A machine shop could easily build these for you.

I used my lathe to make my fuel rails too, but you could find an off the shelf solution (ie: Carrera fuel rails). Also I made an adaptor to fit TPS sensor on the CIS throttle body, but again you could probably adapt some other cars throttle body that is already made for a TPS.

The rest of the stuff, you don't need a lathe, but boy does it come in handy. Once you have one, you'd be surpirsed how often you use it to adapt one thing to another. Best tool in my shop, for sure.

Cost has been mostly my time. The Megasquirt unit was $100US and I'd add another $200US for fuel lines, fuel regulator, six injectors, wiring, air filter, etc...