Ok, lets talk 2.7

[Chuck Moreland]

I realize you are asking about the tbitz setup. It may be able to accept a more aggressive cam than the CIS, and thus make more power. I don't know if anyone has tested this yet.

I've got my own EFI 2.7 project happening, but it is different. I'm putting an EFI setup on top of MFI stacks. All this goes on top of a twin plug 2.7

I'm hoping to accomplish the best of both worlds; MFI throttle response, look, power and sound, EFI programmability, efficiency, flexibility.

Still in the parts collection phase, so I can't report on the results.

[wowzer911]

I like TRE Cup's Recipe

[bigchillcar]

chuck,
that sounds very interesting. do you have an active thread on your efforts to date? but you're correct in what i'm asking about..and no, i haven't heard a peep out of anyone trying it yet..maybe tbitz will weigh in on this thread.
ryan

[bigchillcar]

Still in the parts collection phase, so I can't report on the results.

ahh..re-read your post, chuck..any idea on how long before you have parts installed and reaching the testing phase? i don't guess you have any idea or can speculate as to what power you might be generating? and would it need special octane? i'm guessing this is more intended to be a track application with the twin-plug setup?
ryan

[TRE Cup]

our recipe will work with 91 octane pump for daily driving , but we recommend boosting it with 25% race gas at the track for insurance. CIS tends to go lean at the top end so we think it best to have that extra margin to prevent detonation

[lateapex911]

Chuck-

I am struggling with Webers and am on the verge of taking the same route. I LOVE the idea, but haven't done much leg work yet.

My *idea*, LOL was to get an old MFI set up, use the pump as a "fuelrail" by modding the internals and just leaving the pump empty but attached for original appearances sake, and going with a megasquirt system or similar.

My first question (see how far I haven't gotten with the idea?? LOL) was how to measure incoming air, or is that even an issue?

You should really start a thread on this for brainstroming..I think it would be very do-able, and totally cool

BTW, two thumbs up on the poly bronze parts I got from you ...neat and easy install. Tonight it's the monoballs in the rear...I hope!

[Chuck Moreland]

No thread on this yet, I'll start one once I get to the assembly process.

This motor was a 77 so no injector ports in the head. I'm using MFI tbodies/stacks bored to S specs and rebushed - as new.

I'm going to machine a port into the side of the stack to accept an EFI injector. I'll use a traditional EFI fuel rail.

I'm leaning towards the Autronic controller, but haven't settled yet.

Incoming air can be measured in one of 2 ways. You can use a throttle position sensor (TPS) or a manifold pressure sensor. The sensors are fit to the MFI tbodies. Some systems use a combination of these methods.

[Dan Mc Intyre]

Originally posted by Halm
LOL... Sputtering and pumping happens in the heat of summer as well as in winter! Here is what I do: Turn on the ignition and let the system build some pressure while I put on my seat belt. Next I slowly pump the accelerator 5 times. Finally I hit the starter. It usually takes no more than 2 tries. As soon as it catches I pull up the hand throttle and let the carb’s “clear out”. As soon as they are running smooth, I lower the idle to 2K and off I go. All this takes no more than 2 minutes on a cold morning. Within 3 miles I release the hand throttle and things are pretty smooth until it is fully warmed up.

Hope this is what you were looking for.

Thanks Hal. That is exactly what I was looking for. It seems that it isn't as big of an ordeal as I'd thought. I was even getting excited about S cams and PMO's and how that would run and sound, then I read what TRE Cup wrote:

Originally posted by TRE Cup
here is a recipe for inexpensive build up IF you have some skills at doing the motor yourself:
get a set of JE higher compression p/cs' no more than 10.5 :1
get your ignition distributor recurved to RS specs
get a 78-79 CIS complete injection system (from a carb conversion?)
get a set of SSI's or headerswith twin outlet exhaust
get your cams reground to 964 spec or get the 964 cams with towers
port your heads to 38 mm intake- leave the exhaust alone
when setting up cam timing- go for as much advance in the spec range as possible
you will have a motor that puts out a true 200 hp coupled with everyday reliability. So in the end euro SC performance from a lighter car at low $$ investment. And it will look "stock" to the average Porsche guy

Dave - that sounds like a winner. I really like that idea. I even thought I saw a 3.0 CIS setup on parts for sale the other day. My question to you, then is I see you did not mention twin plugging and I assume that was intentional. Just for clarification, can the Tre Cup "recipe" work with single plugs. I saw you stated it will work with 91 octane for street use. This looks like a great engine idea. Thank you.

Originally posted by Lukesportsman
I went with big bore 2.4 with RS cylinders and slightly bumped compression with milled heads. We setup the pump and ran E cams. This gave us a broad torque band and reasonable pull. I currently run it behind 8:31, but the 7:31 made it quicker out of the hole. I might be lighter than you with my no frills long hood, but it gets out of its own shadow. I have fast cars, and this isn't one of them, but it is a blast on a crooked road.

Luke - I am curious why you went back to the 8:31 instead of the 7:31. Does it make 1st a "granny gear" stump puller?

Originally posted by bigchillcar
what i WOULD like someone to address would be pelican member tbitz' efi conversion.

I have read about this system. But as you can see, I'm nervous about carbs...imagine the anxiety I'd experience with something like that?

Originally posted by Chuck Moreland
I've got my own EFI 2.7 project happening, but it is different. I'm putting an EFI setup on top of MFI stacks. All this goes on top of a twin plug 2.7

Chuck...I can't wait to read about your project. I'll be great day dream material for me.

Originally posted by Grady Clay
Ask Pelican rs911t what he thinks of his big bore 2.4T (2807 cc, 10.5:1 CR, S cams, heads, throttles, stacks, and pump calibration.)

Grady, thanks for the suggestion. I'll research that one for some info.


Thanks for the ideas everybody. They have helped me a lot and fostered more questions still. I guess the research continues.

[TRE Cup]

single plug will work fine with 10.3-10.5:1 compression with decent gas. probably go with 29-32 degrees advance on the distributor.

[Vapors]

I built a'74 2.7 with 10.5:1 JE pistons. Electromotive HPV-1 Twin plug Ignition, intake & exhaust ports opened up to 36mm, and 40 IDC webers with 36mm venturies, Cam was a mild elgin, bursch headers, and early twin outlet muffler. The car was easy to start, tons of power and super fun to drive. Remember the 1974 911 had a lower gear ratio which would help the acceleration.

[bigchillcar]

dan,
tbitz' efi setup actually purports to simplify induction and basically you can remove all the old cis parts, vacuum lines, etc. and it's 'tunable' via a laptop computer..sound it makes is also 'throatier', as it gets rid of the big old airbox and puts a much smaller k&n style filter over the throttle body. an added benefit in my opinion would be the fact that that would create room to easily put a 12 volt electric fan underneath the rear a/c condenser to keep running cold in stop and go traffic..but i digress..
ryan

[duffster]

I've been eyeing ************'s TBI/electronic control-crank fire set up as well. The main determining factor is the 8k+ costs, which I'm not really feelin' right now. Mine runs "ok" on 91 octane around town, but I juice it up with about 25% hotter fuel for track days. I'm going to be hiding in the bushes watching what Chuck does and, of course, I always pay some attention to TRE Cup.

[Dan Mc Intyre]

Originally posted by Vapors
I built a'74 2.7 with 10.5:1 JE pistons. Electromotive HPV-1 Twin plug Ignition, intake & exhaust ports opened up to 36mm, and 40 IDC webers with 36mm venturies, Cam was a mild elgin, bursch headers, and early twin outlet muffler. The car was easy to start, tons of power and super fun to drive. Remember the 1974 911 had a lower gear ratio which would help the acceleration.

Hi Vapors,

Sounds like a terrific engine. Man, now I keep thinking about carbs and S cams. I gotta rethink my views on carbs.

Originally posted by bigchillcar
tbitz' efi setup actually purports to simplify induction and basically you can remove all the old cis parts, vacuum lines, etc. and it's 'tunable' via a laptop computer..sound it makes is also 'throatier'

Bigchillcar -

I dunno, guess I'm a traditional kind of guy. I guess if I went with a different induction system, it'd be carbs. Probably PMO's. It is an interesting alternative, tho. FI is pretty mysterious to me. I grew up on carbs. And used to know how to work on them. Not a lot of mystery on those.

Originally posted by duffster
I've been eyeing ************'s TBI/electronic control-crank fire set up as well. The main determining factor is the 8k+ costs, which I'm not really feelin' right now.

duffster,

I'd be interested in knowing what system you're thinking about buying for 8k. Can you PM the info to me?? Thanks


Dan

[Lukesportsman]

Chuck:
Is there enough material to machine for EFI or are you adding material or spacers for the EFI injectors. I would think that a TPS and MAP would work easily in this application since it shouldn't care if its one big or 6 smaller butterflies.

Dan:
I would have stayed with 7:31 if I didn't figure the HP bug wouldn't hit me in the future. I just went with a 8:31 tranny and later axles now to simplify the move up in the future. First gear is still OK, but could use shorter 2-4 gears with the taller ring and pinion.

I actually doubt I will rebuild the MFI in a future failure....probably go with different induction options as I move for more aggressive cam and compression options.

[CARRERIC]

My .2 cents. Here is the car I had professionally built last year - 1975 911 Carrera 2.7 US. I feel this car is putting out around 200 hp. It is a bad a$$. Still waiting to dyno it.

RS Pistons
SC CAM GRIND (web cam)
Fly cut heads
SSI's , dansk sport muffler
Stock CIS (w/ sc throttle body
7:31 Ring and Pinnion
Engine Case updated and machined by CE
Everything new in CIS from tank to injectors
etc etc...

I have a friend with a 83 SC he just finished cpmplete rebuild with 964 grind, big intakes, euro fuel distributor, ssi's, etc etc... all the upgrades. With a worried look on his face - He is always asking our mechanic why my car is so fast for a 2.7.....

[CARRERIC]

By the way one of the best mods I did was install a new RS spec distributor. Made big difference on the curve.

[Chuck Moreland]

Originally posted by Lukesportsman
Chuck:
Is there enough material to machine for EFI or are you adding material or spacers for the EFI injectors. I would think that a TPS and MAP would work easily in this application since it shouldn't care if its one big or 6 smaller butterflies.

No. I'll be affixing injector bungs to the side of the stack. Basically the stack will just have a hole to spray through.

The bungs will be machined to match the curve of the stack, then affixed with some type of adhesive. I'm using mag stacks.

[bigchillcar]

carreric,
now we're getting somewhere..that's what i've had on my mind for several years, but have been concerned about how much it really improves with the cis. have you seen or heard of tbitz' efi setup? read member 'flipper's' thread on his recent swap from cis to efi on his 2.7..the dude is in driving heaven last time i checked. i'd love to know what it would do on a car like yours..i think it's exactly what i'd wanna do. i think it would be cheaper than carbs or mfi, be more fuel efficient, driveable, programmable. you really need to dyno that car for all of us 2.7 guys you know..
ryan

[bigchillcar]

carreric,
btw, can a rs spec distributor be swapped for my stock '74 model? i don;t have the 's' cams, but i do have the 7:31..how did it change your advance curve basically in driving terms?
ryan

[Dan Mc Intyre]

Carreric,

Sweet car. Seeing as your's is a 75, I assume you converted from an 8:31 to a 7:31. Did you change any ratios in the box? If so, which ones and how do you like your first gear? I'd really like to hear your tranny story, too.

Dan