rdane,

thanks for posting information about your CIS. I have been toying with the idea of going with PMOs or trying some sort of aftermarket EFI. After reading your posts and some from others who actually like CIS, i think ill spend my money sorting out what i already have and take what i saved and buy something nice for myself like driving school or maybe get my pesky 915 rebuilt with the 7.31.

OK; To answer my own question, here's some that I found by doing a quick search...

Jpachards carefully built stock 3.2 with his custom headers:
http://forums.pelicanparts.com/uploa...1086724798.gif

From Steve W, a comparison of a stock 3.2 (EFI) to a 3.2 with a 911chips performance chip..
http://forums.pelicanparts.com/uploa...1093488121.gif

jakermc's 3.2 with the following:
- Euro 3.2
- No cat converter
- Heat exchangers
- 2 in 1 out custom DynaMax muffler
- Bored throttle body by MSDS, cone filter
- Intake ported and polished
- Performance chip, believed to be by Authority
- Magnecor 8.5mm wires
http://forums.pelicanparts.com/uploa...1069536838.jpg

Here are the results from a published article about some BRD modifications. Note that it appears to be flywheel numbers rather then rear wheel numbers.
http://forums.pelicanparts.com/uploa...1062705023.jpg

CamB's 3.2 which had the following specs:
- 1978 SC case and crank, rods
- 98mm Mahle P&C with 10.3:1 c/r
- twin plug (964 dist)
- S cams
- ported and polished heads - 42mm inlet, 40mm exhaust
- standard (1978 - same year as case I assume) SC valves
- early MFI throttle bodies bored out to 40mm, converted to EFI
- MoTeC 3D controlled EFI
- SSIs and standard 2 in 1 out exhaust
http://forums.pelicanparts.com/uploa...1102018699.jpg

That seems to be a pretty good sample. I'll compile the data and share the chart when it's done.

John, BIG problems mixing dynos not from a Dynojet machine IMO....un reliable data as the end result.

I am very careful in my dyno comparisons. It is too easy to skew data either way from even a Dynojet and it is the best of the bunch.

At the risk of interjecting yet another Randy into these data, FWIW, my PMO'd mild street cam SSI twin-plugged 3.2L puts out a tad less than 250 hp - that on an engine dyno.

I am a known, card-carying CIS hater -- but I will agree that it isn't _that_ bad for a street car --- as long as your street car is not a sports car. What is missing in all this, is that CIS slows the engine's "feel." Or "revability" or what not.

Which makes you right about with the rest at 213 rwhp......
The supposed lack of CIS throttle response is way over stated if my car is any comparison to a lwt 3.6 or mid 80s turbos.

Be happy to meet you on the Columbia river, Klickatat grade and give a CIS demonstration :)

What happens when you take a CIS and convert it with TBITZ's EFI kit,do you get the best of both worlds?I really like the simplicity of TBITZ's EFI kit and it still uses the CIS intake runners and partial air box.I am thinking of going this route in the future and would like to hear opinions.

Looks like early next week for the injection molder to run my parts. There is also a few opperations in the mill too.
Need boxes,print stickers...you know, stuff. Its coming I swear!

re overstated - well, I am one of the few to compare two cars with and w/o CIS (Webers). Both had SSI's and a 2.7L. The car with Webers was much heavier. And YET I loved driving it because of the engine responsiveness (even tho both had the stock CIS cams). I owned and drove them back to back for 2-3 years.

So I know the difference -- over an extended time period not just a run up a grade.

But, no, CIS isn't THAT bad....

OK; Here's the graph comparing the torque curves from each of the engines. rdane has a point about comparing dyno results from different dynos taken at different times, under different conditions, yada yada yada. The interesting thing is how close all of the graphs are which suggest that for the sake of discussion the results are comparable.

http://forums.pelicanparts.com/uploa...1102023829.jpg


Some observations:
* The 911chip chip seems to be effective in filling in the mid-range.
* Jpachards headers help at the high end.
* CamB's "short stroke" 3.2 data had to be adjusted because his chart was in flywheel HP rather then RWHP. As a result I discounted all of his numbers by the standard 15%. From an absolute perspective it's hard to say if cam's 3.2 is more powerful or not becuase of the adjustment, but it is pretty clear that it has a much wider torque curve then the other versions. The much higher CR I'm sure helps.

Conclusions: It's not easy to get better performance out of a Porsche engine without drastic measures. Small gains can be achieved by working the details like the right chip or the right exhaust. Conversely, picking some popular modifications which don't work well together can also result in less performance. If you want to make a significant change you're going to need to re-engineer the entire engine.

Thanks Randy,
Dr. Evil smiles again ;)

John, Cam's numbers skew the data unrealistically. Bad data would be my quess. Porsches are nothing if not consistant.

Often repeated engine dyno numbers (and these are good ones as well on Cam's car) but not real world on a dynojet.

Iris (281/244) and Cam's build (273/231) are very similar as are their engine dynos.

Iris' engine dyno and chassis #s off a dynojet.

"281 H.P./ 244 ft./lbs. torque at the flywheel at 6700 RPM's.
(27% hp and 21.5% torque loss by these figures)
Changed muffler and put her on the DynoJet to rejet the carbs and this is what we received. S-CAR-GO Racing dual in/out stainless steel muffler change and we received 222.1 HP and 201.5 ft/lbs. torque measured at the rear wheels at 6500 RPM's"

No pressure, eh? Getting closer to dyno time, I just turned 600 miles with it and am driving it everywhere. 160 miles RT from OC to San Diego today. Another 160 tomorrow. Dry as a bone and other then a slight fan belt tension adjustment, so far so good.

Got to get Steve W. on the red phone to set up a final "optimization" session.

Ralph

Ralph I dynoed mine at 1000 miles with good results and again at 7000 witha reasonable jump up in power and torque. Take your time and do it right.

My bet is your 3.5 thumps everybody but the newer 993 vario ram 3.6s with RSR cams.

so how much exactly is the cost in getting a 3.2l motronic installed in a car vs. building and installing a 3.4 liter CIS with all the coatings and mods needed?

My entire engine build was $13,500 done by a professional shop. I now have a new engine that has no comparison to a stock 3.2 other than they are both flat 6s.

Take a motronic 3.2 and add MAF sensor, cat bypass, bored throttle body, match and flow your injectors and a sport exhaust will almost duplicte the 3.4. You'll still be lacking the torque of the 3.4 and have a used engine. Cost? Easily cut in half what I spent. Rebuild the 3.2 to my 3.4 spec and spend $12,000 or less and have more yet with a new engine.

The reasonable way to decide on what engine is best for you money wise and performance is to take a close look at what you have to start with.

Stock 3.0 or less... do 3.2 or 3.6 transplant depending on budget

Cams and SSI in a 3.0... 3.2 / 3.4 rebuilds are a reasonable option for a new engine.

3.2 with a little work done to it...3.4 / 3.5 is a great option again and can be an exceptional bang for the buck.

Hmm, here we go again.

Noah is 100% right - and I agree with him. CIS's limitation is in the throttle-body design, not in the airflow characteristics.

The Motronic engines and the CIS engines are very comparable, and CIS does a fine job of metering the fuel in this case. I tell people that putting Motec or a TEC-3 system on a CIS *stock* motor is not generally a wise investment, as you won't get much improvement out of it.

The power gains are not to be discovered in changing the fuel injection system, but instead, in changing the mechanical characteristics of the engine.

The true beauty of electronic engine management systems is their ability to let you program the system to match your non-stock engine. Placing Motec on a stock 3.2 would be like placing super-expensive high-performance tires on a stock 3.2 car - it's not going to make much of a difference, as you haven't dramatically changed the engine configuration.

So, I'm not the least bit surprised that your 3.4 and the 3.2 are somewhat comparable (accounting for the change in displacement too). The CIS system does a good job of metering the fuel with the stock (mild) cams. Swapping a Motronic and CIS system back and forth on a 3.2 engine would probably show minimal difference between them (probably a minor improvement in performance with Motronic). The nice thing about the Motronic system (and engine management systems) is that they integrate ignition control (advance/retard) along with the fuel metering. CIS doesn't do that.

Another thing to point out is that early Motronic systems (like the 1984-89 Carrera systems) are generally pretty primative and lack a knock-sensor, which is vital to squeeze the maximum power out of your current octane fuel. While the 1984 Motronic system will offer similar performance to the CIS system that preceded it, a system that integrates a knock sensor should show better statistically better perforamnce, particularly when running on poor quality gas...

-Wayne

Dane, I hope that you are right and I am wrong, but I honestly don't think so. I am expecting 235-240 rwhp with what I have done, anything more is pure gravy. I've seen and driven enough of these 3.4/3.5 CIS/Motronic combos over the years to know they are not going to make huge power. At Andial, we were seeing in the 255-270 CRANK horsepower in the late 80's-early 90's with 964 cams and the stock heat exchangers. I don't think things have changed that radically over the years with respect to 3.2L engine development for street applications.

Michael in PA (89911) has almost the same motor as me, other then 3.4L displacement and SSI's instead of 3.5L and headers. The best he has seen is 229 rwhp but he believes there are a few more ponies on the table to be had with more chip tuning. I really won't expect to see that much more then him. 10 more rwhp (extra displacement and better exhaust) puts me in the range I am expecting.

My goal was/is a nice street motor that has very good bottom and mid-range torque (something the stock or mildly modified 3.2L lacks no matter what anyone says), is easily smog legal and will run on CA's 91 octane. 80 hp/litre (Porsche's most powerful street motors through the years hovered around this number) is my goal with the above constraints and that is what the intent of the build was/is. A stock U.S. spec 3.2L is about 68 hp/litre. Pathetic and leaves plenty of room to improve on.

Ralph

Bone stock Euro 3.2 has 231 crank hp, measured by factory (and they seldom lie). Rdane's 13500$(!!) -improved 3.4 with extra cheese delivers 220hp.

That's laughable.... especially considering that I bought complete -81 300hp euro 930 for 14000$ (more in todays dollars but dollar was stonger then) and even got a set of extra wheels with it.

CIS is not a performance fuel injection system and has very few advantages.

No, it's not reliable. It has lot's of grommets that can fail and when (not if) they fail they demand finicky trouble-shotting involving pressure-measurments, checking analog things that can be "slightly OK but not quite" etc. It's flapper chokes the intake (there are numerous dyno papers to proove that) and it's too complicated.

Yes, there is a group of "good old boys" trying to convince world & dog that CIS is nice and has good torque and yadda yadda but it all depends on your definition of "nice".

If your mech skills aren't good, your idea of "performance engine" is "good midrange torque" and you want to keep your engine stock then I guess it's perfectly OK to keep it there.

On other hand, if you are a tweaker and want more power then I suggest getting rid of it.

Oh, one more thing... where does all this panic about "intake reversion" come from? You get the impression that nothing 'cept full-fledged throttle bodies will do, 'cause Porsche-demon will get inbetween and suck the air from the intake and make your engine explode. Yes, I have read that CIS doesn't tolerate cams that are too wild and I believe it (as I've never had the luxury of dynoing my 930 with hotter cams). Actually, I've seen other CIS-injected 2-valve/cylinder cars tolerating hot cams very well
( here is dyno of 4-cylinder engine equipped with EXACTLY the same CIS as Porsche 930/ MB450/porsche 928 http://luminasweden.com/temp/SAAB99Tkammar.JPG and with different cam profiles) but I'll believe it for lack of better proof.

But I fail to recognise the reasons why a EFI-equipped Carrera engine would suffer from famed "intake reversion"?? I mean, there are literally millions and millions of cars running with hot-cams and EFI w/o fancy ITB's cut from finest steel by virgins during full moon.

Anyone dynoed a Carrera with hot cams and noticed something on dyno sheet that had him say "ahh, that's typical intake reversion, let's buy them 2000$ ITB's , guy on Pelican BB said so"??

Oh, one more thing. It's kinda inflamatory as well ;)

TORQUE DOESN'T MEAN A SQUAT

Really. It's one of those hard-to-understand things that always get skewed on internet forums.

You could install a gas-turbine with 5Nm torque and still run away from 500lb/ft BB V8 provided sufficient revs and matching gearing.

With other words, CIS "torque-advantage" isn't advantage at all. There is nothing magical CIS can do to bump midrange torque compared to EFI. It's just air passing obstructions and getting into engine, getting mixed with gasoline.

What matters, gentlemen, is SWEPT AREA UNDER POWER CURVE.

With other words, if rdane's grunty 3.4 tries to overtake high-revving 3.2 on a highway but his shift points fail to accumulate as much area under power curve as 3.2, he'll get waxed no matter how grunty engine is.

Yes, 3.2 (or 2.7 or whatever) will rev more and produce more noise but it's area under power curve that counts.

So, a few politically incorrect statements:

- Power wins races, sells cars and corrupts.
- There is replacement to displacement and it's called "boost".
- CIS sucks and will keep doing that. Throw those things out and make world a better place.

Thanx for listening ;-)

Either way Ralph I want to see the dynos when you are done. It should be an outstanding motor.

Wayne, thank you for commenting. You are the first to say or write what I have suspected but no one would varify. Hate to have to verify your comments and my thoughts with my money.

As most know Randy built his 3.2 engine to take maximum advantage of the rules in Solo2. So he was limited on what he could do for engine gains. Induction was free, so Motec and Varioram make sense. He is still using the original CIS cam.

As the installer and I discussed my engine and what Motec would do for my engine numbers like 25 more on HP and torque were thrown about as easy gains. Once we got to the computer and actually looked at Randy's 3.2 and my 3.4 and the A/F ratios there was less discussion on gains to the point of now being very noncommital to any HP/T gains.

I have no plans on changing my 20/21 cam. I do think twin plugging would be good insurance to keep my engine together and worth a few points in HP. But the Motronic injection manifold and the CIS injection manifold look very similar.

Just so I have this straight..I think Wayne said..

Motec (any engine management) won't help my engine gain HP or torque? The cams/build define that process and I have a limited platform.

Motec (AEM) will get me consistant max performance out of my engine build and bad gas?

Neither Motec (AEM) or the switch to a Motronic manifold/Motec will gain much over the CIS with my current engine build.?

If all those things are true, can you give me an idea on how "much" you might expect?

Guys are picking up a documented 25% on Torgue and HP going to Electromotive over CIS on the turbos.

Will a NA car gain anything?

Thanks for your time.

Dane

Goran...come on, join the party will you? A stock Carrera 3.2 typically does 200+/- 5hp at the wheels. My 3.4 does 223 at the wheels. If you want to make a point get the numbers right please. 231 and 263 is a better comparison. Peak torque on a factory 3.2 is at best 200# at the wheels usually a good deal less. My 3.4, 215# at the wheels.

$13,500 US dollars bought a professionally installed, brand new engine based on my 3.0 case. Your numbers are bad as are your comparisons. Laughable in fact.

From experience a stock 3.2 isn't in the same ball game..sorry.

Sheesh! What a Buzzkill...
 

This stuff if hurting my head, making me question my normally aspirated aspirations.

Gordo

Mmmkaaaayyy....

14000$ bought me a proffesionally built 300HP engine with (pun intended) lot's of good-old CIS-torque. Around 375lbs/ft as far as remember. Oh, I got a car as well ;)