EFI conversion thread, another one... Options

['73-914kid]

I seem to constantly bounce back and forth between carbs and EFI.

I used to be really pleased with the fuel economy of my 4-cylinder with carbs. I really couldn't complain about 30mpg on a carb'd 2.1L type 4. Well, with gas prices going back up, and having installed the 6, I'm getting a whopping 16-18 at freeway cruise, which is unacceptable for me. The motor is a 2.7 built to RS specs with S cams, and it really does go quick, but either the jetting is off, throttle shafts are worn (I know for a fact they are based upon carbon deposits on the butterflies), or I'm suffering from the fact that the 40's were never really meant for a 2.7, so the transition circuit is hugely rich.. becasue fuel mileage is awful.

Anyways, I have this vision in my head of removing the fuel lines, closing off all of the unnecessary ports in the carbs sans the air bleed screws, and essentially converting them into ITB's.

I would adapt a TPS onto one of the throttle shafts, plumb the intake manifolds for vacuum for the MAP, and then weld in injector bosses/bungs which are readily available, and cheap, from various websites for the standard 14mm bosch style o-ring sealing injector. There would be no permanent modifications to the carbs, just to to the intake manifolds.

Am crazy for even trying to attempt to start collecting parts for something like this? The hope is to not spend a whole lot of money on everything, and keep it bare bones with no ignition control, just fuel control.

Brain would be megasquirt, not sure what version yet, but I was also tossing around the idea of microsquirt. I'm not sure what would be the best avenue for something like this.

Any thoughts on this? Don't do it, don't waste your time? etc.

[914_teener]

Why not MFI?

[sixnotfour]

If your still thinking of selling , don't do it, sell it, but if you want a fun project,,

[sixnotfour]

Why not MFI?

you cant tune it from a laptop..

[rsrguy3]

Look up Al's Retro cool high butterfly setup on Pelican. I have the six in mine too and that's what I'm going with plus I've had a good experience with MS.-G

[rudedude]

Pray tell, tell us more!

[JmuRiz]

Look up Al's Retro cool high butterfly setup on Pelican. I have the six in mine too and that's what I'm going with plus I've had a good experience with MS.-G

Did you buy it yet, I thought he sold that design to D-Zug to market/sell.
Btw his old 2.7 test mule engine is up for sale on eBay, wonder what he's up to next.

[Mark Henry]

Actually If I don't like my fuel mileage I may do the exact same thing. If you hide the FI and fake the carb fuel lines it would still have the look of a carbed engine.
I'd remove the venturies and just install straight tubes.

If you have Webers I'd sell them and get a set of cheaper Zeniths. This would probably pay for your ECU.

['73-914kid]

The plan for this was to be a cheap way of going ITB, and making due with what I have. Would I like to run aftermarket ITB's, of course, but I have the webers, and they make an excellent ITB as is.

Then again, I was also throwing around the idea of the Bitz Racing kit that modifies CIS injection setups..

I believe I could make most of my money back from purchasing the kit and injectors based upon how much a set of used webers cost...

[rsrguy3]

Nathan,
He gave me a parts list. I'll be collecting the parts over the next several months and purchasing his custom fabbed parts directly. If you want the whole enchilada it's like $3200, but as I'm away from home I'll be doing my usual scavenger hunt to build the common items like the brain, t -bodies and wideband. Should be a real gas as I was trying to figure out how to run MS on this app like 3 years ago. Once I have the 911tuned and registered again I'll sell my 40ida 's to offset co Ultimately I'm hoping this will be my DD.

[jpnovak]

Are your heads drilled for MFI injectors? I make adapters that let you drop in EFI injectors. Sell your webers and manifolds. Then buy some good used MFI stacks/throttle bodies for less money. Use the difference to pay for almost your whole MS setup.

There are many ways to get EFI benefits. A CIS plenum would work, would be easy to install. Did your heads get ported? Use a 3.0 plenum that will probably match common port sizes.

I don't think I would close off the webers. Just sell them and put a few hundred into throttle bodies. The current price for nice webers is close to $2K. For $2500 you can get a complete Borla/TWM 3003 setup with manifolds and linkage and TPS and air-horns and fuel rails. Get the idea here? Leverage what you have to offset the cost.

[sixnotfour]

(IMG:style_emoticons/default/agree.gif)
my above TB's have injector ports, cable linkage , and are $50, Mcmark, and I made similar manifolds as did..
http://forums.pelicanparts.com/911-engine-...olaris-tbs.html

[rick 918-S]

The webers are worth way more that you could build an MS setup for. Gather some parts and motorcycle TB's and build the system then sell off the webers. you'll be money ahead and have a fun project.

[colingreene]

Pm me, i have the unique ability to probably help you out with this.
plus im sort on the route you drive between work and home.

['73-914kid]

Actually If I don't like my fuel mileage I may do the exact same thing. If you hide the FI and fake the carb fuel lines it would still have the look of a carbed engine.
I'd remove the venturies and just install straight tubes.

If you have Webers I'd sell them and get a set of cheaper Zeniths. This would probably pay for your ECU.

A while back I picked up a set of Zeniths with the intention of using them on a different 6, however I think I may be using these as possible throttle body options. In my opinin, zenith castings look cooler than weber castings, and they should make nice throttle bodies. Plus, with the auxiliary enrichment circuit removed, there are ports that are left open on the flanges. These can be easily repurposed for MAP sensor vacuum sources.

Also, through work, I have access to a few people with lots of in depth tuning experience on porsche engines, to say the least..

[Mike Bellis]

EFI is awesome! If you have it properly tuned, it will out preform carbs and get better mileage.

ITB's can be difficult to tune but they look very cool.

If it were me, I would get a 3.2L manifold and adapt it to the 2.7L. It will run way better for your commuting and be easier to tune. It is probably cheaper to build also.

You have many ECU choices. in the long run, they will all cost you similar money. Megasquirt will be slightly cheaper but can be more work if you build it yourself. You WILL absolutely need a dyno tuning session. Maybe more than one.

In every EFI build I have done, it has cost $3000-$5000 all in. Amortize this cost versus your fuel cost and the time you will own the car.

['73-914kid]

I actually have possible access to a mostly free Pectel SQ6M ECU. That would take care of pretty much every question mark from the system.

If I can find a carrera 3.2 intake, I will pick it up. I haven't been able to find anything cheap though as of yet, but I haven't been looking intensely.

[bigkensteele]

I am in the same boat with my 2.7. I have all the CSI stuff, so I can go the Bitz route. My main sticking points are a. it uses MS 1, which I don't believe can handle spark, and b. it doesn't look very cool with a hacked up air-box. Toying with the idea of a custom air-box to remedy the latter.

[aircooledtechguy]

MS1 can handle spark, and it's upgradable to whatever you need. I can't imagine using it today though unless it was practically free since the later versions do it all and more right out of the box.

I'm a huge fan of Megasquirt and currently run MS3X in my car. I love the tuneability that it offers.

[toon1]

MS1 can handle spark, and it's upgradable to whatever you need. I can't imagine using it today though unless it was practically free since the later versions do it all and more right out of the box.

I'm a huge fan of Megasquirt and currently run MS3X in my car. I love the tuneability that it offers.

I'm also a huge fan of MS.....BUT....instead of going through all the gyrations of EFI at this point, why not install an 02 sensor and see if you can do better with the carbs.

For $190, you'll get real time readings. You can then try some jetting to see if the MPG's get better.

If it's still not to your liking and decide to go the EFI route, the 02 sensor will be there for you to tune the EFI.