individual throttle body injection on type IV?
 

Greetings -

I assume this has been done before but I though I'd ask...

Has anyone ever considered putting individual throttle bodies (one butterfly per cyl) combined with an electronic fuel injection system on a type IV? I don't think there would be any easy way to measure airflow for all 4 intakes, so you'd have to run mostly open-loop (oxygen sensor?).

This would give something similar to the Bosch mechanical fuel injection used on the early 911s. More than just the HP increase from the optimized intakes, I'd be interested in what such an engine would sound like - especially if combined with a hot cam! I wonder, would it "wail" like a mechanically injected 6?

I've seen the CB Performance EFI setup on a Type 4 before. Basically they fit on a T4 Weber manifold, and look like carbs, but with a fuel rail and injectors per side.

Sound a lot like carbs, but it is EFI with 48mm individual throats.

Later,

G

Wayne Baker used a system from a BMW (I think) on the #22 IMSA 914 that had a 2.2l four engine in it. It was a mechanical system similar to the Porsche mechanical system and from what he said it was pretty hard to get tuned, but it made 250HP plus once it was correct! That car runs a RSR spec 3.4l six now which is much less tempermental! If you want just power and bragging rights, Gene Berg's HUGE IDAs (54mm) are the way to go!

Mike Nugent's car 914lite ran the CB FI setup. Check out the BIG FOUR article in the article section of this BBS.
I never heard it run as he was parting it out before he ever raced it due to some injury he had.
Geoff

Go here for more than you ever wanted to know...

http://www.shoptalkforums.com/bbs/cgi-bin/forumdisplay.cgi?action=topics&forum=Fuel+Injectio n.&number=23&DaysPrune=&LastLogin=


-Rich Hilgersom

I once read an article that Ferrarri 8cyl. uses one fuel injection system per cylincer bank with a single throttle body per bank. Upon further reading it would seem that to save $$$, parent company Fiat (sic) actually came up with the solution which uses two sets of Bosch FI systems that would normally go on a 4-cyl. FIAT.

This got me thinking about doing a similar set-up using 2 sets of Bosch systems from a 2-Cyl. horizontally opposed BMW motorcycle engine. The BMW is a 1200cc air-cooled motor with a modern Bosch MAF style F.I. In theory the system would work on a TYPE-IV up to 2.4L with little or no modification.

You would have 2-MAF, 2-Throttle-Bodies, 2-O2 sensors, 4-knock sensors

I proposed this on ShopTalkForums quite a while ago and was pretty much shot down that it was too complicated, impractacle, etc.

I suppose the CIS & LH-Jet solutions people are coming up with are simpler (VW, Volvo, SAAB, & Mercedes sources Bosch units usually) . The LH-Jet would probably make 99% of the people who own Type-IVs more than happy. I still think the BMW sourced system proposed above would make for a sreaming engine and probably cost less than most of the programable racing style aftermarket systems.

That said, a lot of my crazy ideas do tend to conflict with the popular beliefs. I was the kid that wanted a 914 when all the other guys were buying Monte Carlos, El Caminos, & Cutlass Supremes, so what do I know ;)

That BMW system is probably Kugelfischer (sp?) off the BMW 2002 tii, or something very similar. If it's anything like Bosch MFI it's extremely expensive to be rebuilt, injectors are $100 a pop, etc. Anyone who puts something like that on a 914 and gets it to work is very hard-core!

Like a few have said, this has been done a few times....

IMHO, a 914 Type IV will never sound like a 911 engine at full song....part of the beautiful noise of the 911 is from the chains for the cams :)

With 4 t/b's, flow can be still measured with a MAP (manifold absolute pressure) sensor or you can run it Alpha-N, which is still electronicly controlled.

With Alpha-N, you are sorta mimicking the MFI since the amount of fuel and air is not measured directly, you are using the position of the throttle to set how much fuel is sprayed.

Alpha-N is used for very agressive cams.

A true independant-runner setup (four throttle bodies, no air connections between them) is gonna give you a really nasty MAP signal. The pressure is gonna pulse wildly because of the opening and closing of the intake valve. This will result in a very uneven mixture.

You could dampen out the pluses, but this will introduce a lag into the MAP signal. You can tune around this by using the throttle position sensor, but that seems to me to be a band-aid on top of a band-aid.

With an IR setup, alpha-N is the only way to fly, IMHO.

--DD

Why wouldn't you set it up like they do with other modern multi throttle plate system, like the M3? Here, you have a common airbox that all the intakes pull through a heater wire mass flow meter.

If we're off in outer space on this topic, while we're at it, what about adding variable length intake runners so I can get low-end torque and high-rpm HP, too? I also want this to be an ultra-low emissions vehicle, so let's have the dual cat / 4 O2 sensor setup, too.

Redesign the heads for four valve with central plug. Whoops, heat's way up, so let's use the 911 shroud and/or water-cooled heads. Gotta have a couple of external oil coolers, too. Damn, can't see how to do the heads with pushrods, let's go to chains.

Latest Motronic or Siemens engine controller, of course. Knock sensors, crank-fired ignition, coil-on plug, etc. Everything coated with the latest high-tech stuff for proper heat management. We should probably bump up the displacement to at least 2.5L, hell, let's turbo it too.

I'm figuring if we're going for reliability, we'll keep the compression to 10.5:1. A solid 350 hp and 300+ ft-lb torque sounds good. Guess we've got to ditch that wimpy clutch and 901 box, too.

Gee, sounding like a 4-cyl verison of the 993 Turbo's motor. Hmm.

Didn't the 3/4 midget cars run F/I when they were (or maybe they still are) running VW engines? Wasn't it a Hilborn (thats not the right way to spell it) setup? They had the big 8" stacks sticking up.

As I recall, the Hilleborne (I think that's the spelling) injection only really works at full throttle. At anything else, the mixture is evidently really badly off.

--DD

Than it should work fine in my car! My foot is always to the floor.

ha ha...

Hilborn injection is ran with Alcohol (which requires almost twice the amount of fuel) Very high volume and very high pressure. The hot ticket is to convert Hilborn injection stack setups to electronic.

DaveD,

Even with individual stacks you still have to have a common vacuum source. The VW guy's build a small box and have lines from each throttle body running to it so the MAP sensor has a common source.

The "brains" of this list ROCK.

PB.. let me know when you want to move back to NORCAL. A certain exhaust company was developing its own replacement brain for the Motronic cars. SOMEBODY needs to pick that back up and take off running again....

Oh.. MikeM... The V8 911 has a 655 lift roller cam in it and runs closed loop. AlphaN didnt help.

B

I didn't mean to make it sound like you had
to run an Alpha-N system with a big cam, it's just they are a little more freindly with it compared to the others.....no personal experiance, just going by what I've read........

PB wants to rain on our parade and 'dis us for thinking outside the boxer :D

There will always be nay sayers (I just wish it wasnt PB) LOL

Maybe we can pay him off to be quiet... :)

B

Maybe I'm jealous 'cause he's got an M3 to play with as well...nah, i don't think so...

My ideal setup would be a stroker kit on it, maybe 2.3 ltr or so, with water/alcohol injection and turbocharged maybe 3-4 psi street, and pumping 9-10 race(thats really low but hey its not a 944t engine ;),) basically airfilter, turbo, Fi, slick setup IMHO. Hey its just my idea, im still working on my little 36 carbs on my 2 ltr, feels like 60-70hp or less.

Hey, I ain't no nay-sayer. I'm just teasing about all the paper engines we see posted here. I'm very impressed by those who have gone and actually built their dreams - e.g. the guy who has a 962 engine in his 914, for example! Or how about the guy who has the 4-cyl chopped-down 911 motor? Wish I had the time, $$, and determination to build one of these way-out motors.

Play with as in drive, yes. Play with as in work on, no, and that's part of the appeal of the 914 to me. The M3's too friggin' complex for me, I have to dole out $$ to my mechanic.