Why EFI?, maybe excellence was expected and they came as close as they could.. Options

[Gunn1]

you are the op , obviously you are a retard, corndoggfhohole, a retard, where we going with this ?

I would say your crossing the line bud.

I have a niece that has Down's syndrome. People have used that word to describe her.
That is a vile description of someone that has a learning disability.

Using that type of language is not acceptable.

I think you need to apologize

[Mueller]

this is the stupidest thread i have ever seen. i think rabys response covers the controversy pretty eloquently.

Huh, and yet "this is the stupidest thread (you've) ever seen... (IMG:style_emoticons/default/unsure.gif)

Your welcome to your own opinion, but The fact there were so many replies with really great data proves anything but it being The stupidest thread you've ever seen.

Just because people disagree doesn't mean their point of view is stupid

No relevant data was posted, (the dynamometer graph has nothing to do with the factory using EFI)

Jakes comment has nothing to do with the factory using EFI. Even my comments do not answer it completely, it is pure speculation until we see something in writing or a video from someone at Porsche (or perhaps Bosch) saying why the switch to EFI.

[injunmort]

what data? one guy from england posted a dyne sheet from england with carbs
. vague on the build, this is your proof?

[Gunn1]

this is the stupidest thread i have ever seen. i think rabys response covers the controversy pretty eloquently.

Huh, and yet "this is the stupidest thread (you've) ever seen... (IMG:style_emoticons/default/unsure.gif)

Your welcome to your own opinion, but The fact ther

e were so many replies with really great data proves anything but it being The stupidest thread you've ever seen.

Just because people disagree doesn't mean their point of view is stupid

No relevant data was posted, (the dynamometer graph has nothing to do with the factory using EFI)

Jakes comment has nothing to do with the factory using EFI. Even my comments do not answer it completely, it is pure speculation until we see something in writing or a video from someone at Porsche (or perhaps Bosch) saying why the switch to EFI.

I got a lot out of it,

Thanks

[gereed75]

Thanks Brant. I think I will lower my float levels a bit and then keep on keeping on.

This board can be a bit harsh at times, but Injin seems out of srts...should crawl back under his rock or back into his bottle

Thanks all and thanks again Darren

[Bulldog9]

(IMG:style_emoticons/default/poke.gif)

[Bulldog9]

Those graphs were great, thanks.

Not sure they answered the mail on 'why' or driveability, but that was good data and makes total sense as I am trying to dial in my Dellortos. I'm using that data to go a bit smaller on my main jets and larger on my accel pump jets. LOVE this forum.

Not related to your graphs, I find the comments about this board being 'harsh' a bit amusing. I've been on BB's since the early 90's with SAAB NET and the XS11 Forum and from Jeep to SAAB, to G Body to COG, FJR, Subaru and a couple others, 914 world is total chill, and has been the best community so far and virtually troll and moron free. A bunch of cool guys, helpful and absolutely generous and gracious. IMO, the person who encounters troubles here brought them............

Look guy's,

I've got outta my seat and spent hard cash to obtain some (what I consider anyway) good information then willingly shared it free for the world to see on here.
I am asking nothing in return.

I'm not taking sides on the Carb v FI debate.

The data simply shows how jet sizing in a 914 with retro fitted carbs effects:

Air Fuel Ratio (and consequent mpg)
Driveability through rev range shown as torque
and Horsepower.

Whilst showing that factory HP & Torque specs can be met, by having to compromise on mpg.

I searched previously for some hard data, and basically came up with just strong opinions, so sought to obtain impartial facts that can be used to illustrate what's going on when you swap jet sizes, and the quirks in the graphs that you might not necessarily have predicted in response.

That's all folks......

[veekry9]

https://www.youtube.com/watch?v=60Lb3-kYvc8

https://www.youtube.com/watch?v=vK8OX8xbka0

(IMG:style_emoticons/default/happy11.gif)
/
https://www.google.ca/?ion=1&espv=2#q=k...mp%20for%20sale
Since 1968,efi has been the way.
Retro-fitting carbs to an injected T4 can be made to work tho.
Mapping egt back to back on a dyno is one way to make a valid comparison,quickly.
Another is time consuming trial and error testing,one change at a time,a seat of the pants,'feel' method.
The factory abandoned the mechanical carbs over injection 5 decades ago,so,
the question the op should have asked is 'Which efi system is most suitable for my application?'
http://www.total911.com/technology-explain...fuel-injection/
/
Gee,I wonder who will be the first to offer a DFI system for the TFour.
Get sum soon.
https://www.google.ca/search?q=direct+fuel+...gwvt4uUakTUM%3A
http://www.hotrod.com/how-to/engine/1501-d...-future-of-efi/
(IMG:style_emoticons/default/biggrin.gif)

[wndsnd]

Too Funny Veekry (IMG:style_emoticons/default/laugh.gif)

[Bleyseng]

Here is my dyno chart from when my 914 2.0L was bone stock with newly fitted Djet.

[914_teener]

So......


Flatter torque curve with FI with aprox. a 5 hp gain with carbs.

For my street car I.ll take FI for a stock config.

[Darren C]

Here is my dyno chart from when my 914 2.0L was bone stock with newly fitted Djet.

Wow Geoff, thats great info. opening two tabs on my PC I can bring up my graph and yours and flit between to write this post. To make it easy for others I've edited it in here so you can just scroll up and down for comparison...

(IMG:http://www.914world.com/bbs2/uploads_offsite/i265.photobucket.com-18255-1465932137.1.jpg)

914_teener, the torque curve is about the same no flatter or curved between the D-Jet and the Weber 40 IDF's.
Take a look at the RPM scale at the foot of the graph, mine starts at a lower RPM, so by the time I'm at 2000rpm I'm making Torque about 118, peaking at about 122 whereas Geoff's D-jet torque peaks at 108 and his RPM trace starts at 2000 which is why it first appears flatter. (eggs & eggs scenario) if you could see Geoffs trace pre 2000 rpm it's gonna curve like mine. In fact you can just see it curve down, so if it were extrapolated I'd guess you'd be around 90-95 torque at 2000rpm Geoff....I'm making 118 torque at 2000 rpm on a 135 jet! (105 torque on a 125 jet and 108 torque on a 140 jet both at 2000 RPM both above the stock D-jet which is kinda curious too)

Brilliant data to show some "basic" comparisons Geoff. Thanks so much for sharing it's really made my day to see this real newly fitted D-jet data.....

Taking into consideration the US and Europe DIN & SAE scales I'm still up by 6% on peak torque WOW, I'm up by 15% on torque at lower RPM (2000rpm) and that's a real driveability bonus. Wow, Wow!

Don't suppose you have an AFR trace do you Geoff? I'd like to see what the trade off in mpg looks like between the two.

Thanks again Geoff, this thread just got a whole lot more interesting.

[stugray]

https://www.youtube.com/watch?v=60Lb3-kYvc8

https://www.youtube.com/watch?v=vK8OX8xbka0

(IMG:style_emoticons/default/happy11.gif)
/
https://www.google.ca/?ion=1&espv=2#q=k...mp%20for%20sale
Since 1968,efi has been the way.
Retro-fitting carbs to an injected T4 can be made to work tho.
Mapping egt back to back on a dyno is the only way to make a valid comparision.
The factory abandoned the mechanical carbs over injection 5 decades ago,so,
the question the op should have asked is 'Which efi system is most suitable for my application?'
http://www.total911.com/technology-explain...fuel-injection/
/
Gee,I wonder who will be the first to offer a DFI system for the TFour.
Get sum soon.
https://www.google.ca/search?q=direct+fuel+...gwvt4uUakTUM%3A
http://www.hotrod.com/how-to/engine/1501-d...-future-of-efi/
(IMG:style_emoticons/default/biggrin.gif)

Carbs vs EFI sounds surprisingly like this:


https://www.youtube.com/watch?v=FL7yD-0pqZg

[stugray]

And here is a question that I pose whenever this comes up:

IF EFI is superior AND Porsche had EFI on the 911T & 911E (both MFI & EFI) then why did they opt for carbs on the 914-6?

The answer is: They intended to race the 914-6 from it's inception, and they knew that carbs provided more adjust-ability than the EFI did at the time.


Now if you want The tuneability of modern EFI with the "vintage" appeal of the stock EFI, then you can use 100% stock EFI parts from the D-Jet and add a Megasquirt for the ECU.

Two guys in my vintage racing group did exactly this.
They use 4X stock throttle bodies for ITBs and run E85 controlled via Megasquirt.

I am not positive, but I think they use aftermarket MAP sensors in place of the MPS.
Although I could make a circuit that would use the stock MPS and provide an analog output that the megasquirt can read and mimics a MAP but that just sounds like a lot of work.

[Jake Raby]

The EFI system being more tunable is both a pro and a con for some people. The benefit comes from the ability to dial in fuel every couple hundred RPM, BUT the issue with this is that all of those increments require perfect tuning.

Again, this is why PEFI is not for everyone, but its also why some people love it.

I have cars with stock EFI, CIS, PEFI and carbs. They all have pros and cons, but at the end of the day I like whats simple.

[Darren C]

I have cars with stock EFI, CIS, PEFI and carbs. They all have pros and cons, but at the end of the day I like whats simple.

Couldn't agree more Jake. I have cars with all manner of fuel delivery too, but the simplest always give me less trouble and when and if I get trouble, they're normally easy cheap fixes.

[Root_Werks]

I like carbs and they have a place for the appropiate application. But, I've never really thought of them as more than a somewhat metered fuel leak.

Carbs only have a few inputs which AFM is adjusted. FI simply has more.

[stugray]

I have cars with stock EFI, CIS, PEFI and carbs. They all have pros and cons, but at the end of the day I like whats simple.

Couldn't agree more Jake. I have cars with all manner of fuel delivery too, but the simplest always give me less trouble and when and if I get trouble, they're normally easy cheap fixes.

One person's 'simple' is another person's 'complex'.

Which is more 'simple'?:

Plugin in a laptop to an OBDII port, download ROM from ECU, edit a table using a hex editor, reflash ROM to ECU?
OR
Pulling off an air filter, removing a mainjet holder with a screwdriver, swapping main jet, then repeating this 3 more times and replacing air filters?

Ask 5 people and you will probably get 3 different answers.

[Darren C]

Ask 5 people and you will probably get 3 different answers.

I totally agree with you Stu.

But at a guess I'd say that most folk on here would find it easier to lay their hands on a screwdriver at the side of the road than a laptop to an OBDII port, download ROM from ECU, edit a table using a hex editor, reflash ROM to ECU. :-)

[damesandhotrods]

And here is a question that I pose whenever this comes up:

IF EFI is superior AND Porsche had EFI on the 911T & 911E (both MFI & EFI) then why did they opt for carbs on the 914-6?

The answer is: They intended to race the 914-6 from it's inception, and they knew that carbs provided more adjust-ability than the EFI did at the time.

Using that kind of logic would lead one to believe that the 910, 907, 908, 917 and so on were never intended to be raced. Because those cars were all fuel injected. The 914/4 and 914/6 were too good, giving the 911 fits remember. The 914 got the 2.0 911T to keep it slower than the 911, so the FIA homologation required it to race with carbs. In SCCA, Porsche and SCCA made a deal to allow the 914/4 to race with carbs instead of the OG fuel injection…