2.4 question... from carbs to MFI or EFI?

[carreraplanes]

Not sure why people think MFI is uneconomical. My 2.7 RS spec motor with compression bump, 3 angle valves, lightened flywheel, boatailed cases, no other mods gives 30 mpg (imperial gallons not USGs which are smaller). Thats on a 250 mile round trip that sees a couple of blasts up to 120, some laid back motorway cruising at about 80, and some pedal to metal country road blasting. Set up by the best man for the job in the UK Bob Watson. Couldn't believe how good it was so went back and checked it again. Same result. Probably only 3 people in the UK that know how to setup the MFI system to this level. Many more think they can though....

[CaptainCalf]

Bryan, that setup you have now is very clean and simple. Why in the world would you want to add EFI or MFI?

I'm sure you have a good reason, but I don't think MFI would make you as happy in the end as EFI would, depending on your goals the EFI gives you almost infinite options. EFI wont be cheap especially if you do it to the detail you've done your other project cars and man they all have been very nice!

If it were me I'd just tune those carbs and drive it like you stole it!

Good luck either way,
RC

[lindy 911]

Originally Posted by CaptainCalf

Bryan, that setup you have now is very clean and simple. Why in the world would you want to add EFI or MFI?

I'm sure you have a good reason, but I don't think MFI would make you as happy in the end as EFI would, depending on your goals the EFI gives you almost infinite options. EFI wont be cheap especially if you do it to the detail you've done your other project cars and man they all have been very nice!

If it were me I'd just tune those carbs and drive it like you stole it!

Good luck either way,
RC

Kinda what I've been trying to say...

[x98boardwell]

Thanks for all the input guys. It was my curiosity that led me to this question. It was more of me just understanding MFI and EFI more and was curious on the expense of switching and what makes the most sense. I don't mind carbs it is just voodoo to me and I need to get better aquatinted with them so I know how to tune and ensure they are running properly. My motor has roughly 220hp and the car weighs 1,400 lbs so it's not that I need more power. If I do, I would absolutely need and LSD before hand.

This was great reading for sure and appreciate all of your input and expertise.

I will update if I end up doing anything.

Regards,
Bryan

[Raceboy]

Originally Posted by carreraplanes

Couldn't believe how good it was so went back and checked it again. Same result. Probably only 3 people in the UK that know how to setup the MFI system to this level. Many more think they can though....

Key is to use a decent datalogging of lambda, rpm, tps and intake temperatures and make adjustments based on those. Many just adjust and go by the butt dyno but most often that approach will not result a well driving and powerful engine but rather poorly running or worse, failed engine.

I have set up only one MFI (on a customer 2.4 S engine with 2.2 S pistons and RS 019 MFI pump) and it runs very well but took few days to get running well with datalogging. I don't know what mpg it gets but it doesn't run pig rich on low loads and hedgehogs are still alive after driving this thing on country roads

[Henry Schmidt]

Originally Posted by Raceboy

......... Many just adjust and go by the butt dyno but most often that approach will not result a well driving and powerful engine but rather poorly running or worse, failed engine.
...............

Wow, I've been tuning MFI Porsche engines for over 30 years and have owned most the latest and greatest electronic devises that technology had to offer and to this day, my butt dyno has served me well.
I guess I just kept getting lucky.
If only Racerboy lived close enough to tune my engines.
I would really like them to run as well as he can tune them.

Just teasing but the arrogance is strong with this one.

[Raceboy]

And again someone misunderstood me and took it personally. Why start to mock someone just because YOUR opinion and experiences differ?
Perhaps you should try to post a bit more constructive and technical answer than mock me and say that I am wrong with only the fact that you have done something 30 years?

It is not the electronic devices, it is about gathering data. And for example reading spark plugs counts also, what I meant was just turning screws and judging by butt dyno without measuring and checking.

There seems to be some weird attitude here in Pelican, or it just seems like that: there is few guys that are long in this board, have done 911 thing for quite some time and are respected (my respect to you too, don't get me wrong) but when something new, or different is introduced by someone, instantly a protective and unfortunately offensive position is taken.
Guess what, you are not alone in this world who build, tune and hot-rod 911's and Porsches in general. There are many other people who are not wrong automatically because their approaches and methods are different. I guess dynos are for fools and WBo2 plus other datalogging devices are for pussies who cannot tune like the real men (read: who can afford several engines to fail until learned from mistakes)?
I don't know if I have tuned my engines good or bad, I just know that they run well and haven't failed because of tuning error.

If I'm wrong, please correct me.

P.S. If it's ok, I would propose concentrating more to technical stuff and not personal attacks?

[Jeff Higgins]

Originally Posted by Henry Schmidt

Wow, I've been tuning MFI Porsche engines for over 30 years and have owned most the latest and greatest electronic devises that technology had to offer and to this day, my butt dyno has served me well.
I guess I just kept getting lucky.
If only Racerboy lived close enough to tune my engines.
I would really like them to run as well as he can tune them.

Just teasing but the arrogance is strong with this one.

Henry, with nowhere near your experience in this game, I did find my LM-1 to be invaluable in setting up my MFI pump on my oddball 3.0 build. I think what this kind of technology has done, if nothing else, is open this up to duffers like me who like to fart around with this stuff. All it really takes is a basic understanding of how the system works, too much idle time, and an LM-1 to tell a guy what is happening, and most anyone with any sort of common sense can make this system sing. And I've had a ball doing it.

[lindy 911]

Bryan asked in the beginning if he could change from carbs to MFI or EFI. Responses said yes but be prepared for the cost. I don't know the entire cost of MFI but a quick search showed parts alone (before rebuild) are worth $3,500 or so. I'm guessing when I say $7,000 all said and done. I have to admit, it looks awesome!

A proper EFI set-up with ITBs (no disrespect to your assortment of parts) and tune will be $3,000 for ready-to-use ITBs, $3000 for ECU and related parts and about $2,500 to tune. I know you're going to tell me I can use parts from a Voltec 2.4 miser-geezer and coble together my own system for far less. I don't dispute that. Personally, I don't think I would be happy with the look of it.

I had the opportunity over the weekend to run my 3.0 with Webers against a 3.2 with Motec and PMO ITBs. Similar cams, my compression is a little higher, I have headers he has SSI. They were almost identical; he pulled me on the bottom end but did not pull away, maybe a car length by 100. He has a painted interior with roll cage. I have no interior! Ha.

I also tried my luck against a '76 tub with a fresh 3.4 and 50 PMOs for reference. He dusted my ass.

As I said in my first post, it can be done but don't expect anything more than what you already have.

[Raceboy]

Originally Posted by lindy 911

A proper EFI set-up with ITBs (no disrespect to your assortment of parts) and tune will be $3,000 for ready-to-use ITBs, $3000 for ECU and related parts and about $2,500 to tune. I know you're going to tell me I can use parts from a Voltec 2.4 miser-geezer and coble together my own system for far less. I don't dispute that. Personally, I don't think I would be happy with the look of it.

The beauty is in the eyes of the beholder as the saying goes. My point was that the $3000 total EFI+ITB kit does the same job as $8000 and the word "proper" goes to the same category as "beauty" as long the chosen solution does its job as well as more expensive.
As for standalones, if the owner cannot tune itself, all comes down to the tuner who is available nearby and what systems the tuner knows best.
In next month I will be converting a 993 into ITB+standalone ECU combo, the budget for that is also less than $3000 and I can show you results from the dyno afterwards. If someone is interested in this at all that is.

[lindy 911]

We seem to be going in circles; where is this $3,000 EFI+ITB total system?

[Raceboy]

Read the above please, it would be a bit silly repeating myself all the time.

[lindy 911]

What's silly is that you can't provide the info on your calimed $3,000 EFI+ITB system...

What's even sillier is that I keep responding to you. Over and out Raceboy.

[Raceboy]

Originally Posted by lindy 911

What's silly is that you can't provide the info on your calimed $3,000 EFI+ITB system...

What's even sillier is that I keep responding to you. Over and out Raceboy.

Read this:

Originally Posted by Raceboy

I did a 2.7 conversion for a friend with VEMS ECU using 315 cc Bosch injectors and Bosch 3x2 coil-pack, ITB's from GSXR750 (these already have TPS and injector mounts), custom fuel rail from Aeromotive profile. Total cost of parts was ~1500 euros and labour cost (fabricating fuel rails, installing parts, making harness and tuning) was 1000 euros. I have to dig in my laptop for photos.

This was information about this setup. I mentioned about the photos also. It's a bit hard to take photos of the car that is over the sea and I am away from home also at the moment but if you would have a little bit of patience, then I could show them. Or 993 ITB conversion. But since you apparently don't have any interest in EFI system and at first tell that it is impossible, then that it is not proper system, I'm kind of at loss whether anyone is interested in it or not?
What supposed to be technical discussion was turned into personal attacks and I still fail to see any serious facts about your statements besides that "it is not possible" or "it is not proper". If you decide to honour me with communication again, would you care to tell me what ECU's you would prefer and why?

[trond]

I am interested in your set up, especially the ITBs and fuel rails. A picture would be very good to make it easier to get the right ITBs and rails

My current setup with Megasquirt 2 and EDIS ignition (but without ITBs) must have been well below 3000 btw all complete and tuned, and it works beautifully. Why anyone would prefer another ECU than the versatile and user friendly Megasquirt in their old 911 is beyond me. I can still see how some might prefer an all mechanical system too as I have it the same way with my bikes where I would never consider fuel injection for some reason that I am unable to explain

Regards

[lindy 911]

The later year GSXR-750 / 1000 Kehin throttle bodies are 42mm and will support about 40 HP; not bad. There would need to be a manifold of some sort fabricated to adapt the body to the intake port and the butterfly needs to be about 200mm above the valve stem. Also, the ITB come in a set of two, two throat bodies. They would need to be modified to use only three of the four throats. That in itself would be pretty tricky. The rest of the set-up seems pretty straight forward.

[lindy 911]

[al lkosmal]

Carbs, MFI.....ITB/EFI.................these are all great systems with their associated strengths and weaknesses. People tend to focus on the differences without acknowledging that they have some important features in common.

Can you say Independent Throttle Bodies? I knew you could.

I've have enough "hands on" experience with all of them to be dangerous...but I am learning by doing, with the help of others that are also doing.

After playing with Webers, Zenith's and MFI, and going through the search for 30-40 year old parts, etc..................5 years ago or so I started exploring the possibilities of finding a relatively inexpensive approach to achieving the same, or better, results as these systems....using more modern and readily available parts. I also spent many hours playing with the Bosch K-jetronic CIS system on my 77S, so I liked the instant cold start/idle characteristics, but understood the tuning limitations of common plenum intake designs, etc.......................one of the paths i decided to follow led me to motorcycle throttle bodies. Readily available, relatively inexpensive, sized properly for many applications....etc. One thing led to another.

The Triumph Speed Triple T'bodies are 42mm at the top , approx. 41mm butterflies. Not big enough to support big race motors, but great for street-able 911 hotrod motors, for sure..including 3.0 and 3.2's...i would think There are some good choices out there. I have now implemented a few systems using ITB's and Megasquirt. Definitely not for the faint of heart, but definitely for the dedicated DIY hot rodder that wants to combine the features that we love about independent throttle body intakes (like Webers and MFI) with modern engine control. i've used some very nice TWM ITBs and I've used my home brew Triumph set up....also very nice T'bodies, and both work very well. No significant difference, from an end user standpoint, between the two.

The fear factor for most is the education part of it. You do need to study up a bit to gain an understanding of how to "program" the ECU. A lot of the information out there is presented in engineering terms and may or may not be easily understood. Most of us hot rodders grew up on carbs, know them and love them...............and programming the ECU just isn't happening.

(that being said....many of us that love the carbs and MFI........can't, or don't work on them or understand how to tune them either)

But, if you have mad hot rodder skills and are willing to put in the time and want to expand your mental "tool kit" a bit, this is a great entry level way to get into it. I'm having fun with it, while still learning about it. The acceptance is growing and the DIY EFI community is growing...........quite a few of us are exchanging notes, ideas, maps........etc.

regards,
al

PS: I have nothing but respect for those that have a vision, dig in, and produce something that others would not attempt...............Jeff Higgins 3.0 w/MFI runs like a scalded dog..............however I only get to view it from the back, because i can't keep up with him.

[al lkosmal]

Originally Posted by lindy 911

We seem to be going in circles; where is this $3,000 EFI+ITB total system?

X-Factory (Kosmal) ITB/EFI KIT

[Raceboy]

GSXR throttles from 2001-2002 (K1, K2) are all separate and easily adjustable to different cylinder spacing using custom bushings. Also extensions are needed to be welded on the linkage but that is all that is needed for adaptation.

Making the flange for 911 is also easy: One of my friends made a CAD file in SolidWorks and I just had it watercut out of 10mm aluminium sheet (material + cutting cost me ~50 euros) and welded a hose connections in order to fit ITB's (doesn't let eat and vibration to the throttles and intake, also easy to disassemble).


GSXR 750-1000 are 48mm ID, 54mm OD at inlet and 42mm ID, 48mm OD at exit.