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niacc

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I now own a couple of E9s and have completed paint and general sprucing up. Enjoying them both.

Now, I'm ready to play. Can I tell if I already have a 3.5 motor in one or both? Assuming I do not, what models would be the best donor cars for a core for such a project?

What can I expect from a triple weber conversion along the lines of driveability, mileage, and performance?

I've been collecting parts to install an AC in one of them. I have all but a compressor and brackets that may be required to mount one. Any advice on best choices? Past experiences? I plan to make it a R134a system, so that may be a factor in what compressor I use. I have a small one from a Z3 M Roadster. It has a serpentine pulley, so I am not so sure it is a good candidate.

Sorry for the ignorance........but I'm late to the party.

Dave
 
Archive

Yes, a little. Some good info, but maybe I am missing some. I'll continue to rummage there.......feel free to point if you know of some particularly helpful locations.

Dave
 
I believe that if you look on the block just under the forward intake manifold you will see some large letters (1.5"-2") reading 3.0/3.3 if you have a 3.0; at least that is what mine has and I have always assumed it implied the basic block size.
 
Well, I guess you're going to have double the fun, what a lucky dog. Am I correct to assume that you have two carburetted CS's. If you coupes have 3,5 engines, yes the blocks are stamped with a coma(Europeans use comas as we American use periods) then you should see this designation on the intake side of the block.

3.5 engines reguires a lot more fuel and air than a Zenith or Weber downdrafts carbs can provide, therefore a triple sidedraft carb setup or fuel injection are needed for correct fuel deliveries. There is nothing like the sight and sound and the performance of a Weber triple sidedraft equipped coupe. The induction roar is a sound to die for as the beautiful eye candies of the Webers. As for the performance and the reliability, awesome power delivery when properly jetted and tuned but reliability suffers in higher elevations. some other drawbacks are lousy fuel mileage and maybe hard cold start issues, don't know if this Weber setup has carb
choke mechanisms. Finally, there are probably very few qualified mechanics who can properly tune and syncronize these multiple carb setups.

If you're interested in a 3.5 engine conversion, there are few options available. One is to mate the block with the second generation oxygen sensor equipped Bosch L-jetronic fuel injection system of the 1979 to 1981 BMW's such as the 528i, 633 CSi and the 733i of this period. The 02
sensor system regulates the fuel mixture a lot more efficiently and precisely than the the earliest L-jet system, giving a little more power and less emmisions. Another option is to fit the Bosch Motronic equipped 3.5 engines of the mid and late 80's. These 3.5 engines were derived from the 535, 635 and the 735 models of this period. These units could be ecu 'chipped' and gives superior power and good driveability although 91 octane or higher is required. All the used engine components are plentifully available and reasonably priced from BMW salvage yard. Many of these parts are still available new from BMW dealers, but are hugely expensive.

Whatever performance upgrades you decide on, good luck and enjoy driving you cars. Two CS coupes, how lucky can one guy get?

Bert
72 3.5 CSi (L-jet, Getrag 265 5 speed, 4.10 LSD)
88 M6
 
Sorry I missed your car listings, you do have a CSi. You already have most of the components for a 3.5 engine swap. Basically you'll need the Bosch L-jet engine parts such as the engine control unit with its complete wiring harness and the associating relays. Also you will need a different air intake plenum, throttle body, and the airflow meter. The round tubular fuel injection rail with it's 6 fuel injectors are also needed. Also, you'll need a new vaccum assisted fuel pressure regulator.

As I previously stated on my other post, your best bet for a donor car is the second generation Bosch L-jet system of the 79-81 cars. If you're lucky enough, you may find a 3.5 high compression motor from the Euro 635 CSi from this same era. The engine setup of the CS Bosch D-jetronic and the later L-jetronic systems look pretty similar to each other saved for the big air filter of the CS and the waffle shaped airflow meter of the L-jet equipped car. Personally, I prefer the banana or C intake runners of the D and L-jets to the clunkier squared off induction units of the later cars of the mid to late 80's. Sorry cannot provide you with any A/C info.
 
Thanks for the reply.

You note that I have one of each. I am driving the CSi now and will have the CS on the road within a week or so. Just reassembling after paint work, now.

You have me on a mission to look for that comma on either of them. Both motors are in great condition and may just be original. Neither car has clear mileage history, but either one could be a genuine low mileage example. I bought them with body damage issues.

I like the look of the CSi intake runners as well. I think I saw an example of the conversion you speak of, using the original runners at Carl Nelson's place.

I likely won't mess with the CSi anyway and go for the triple webers on the CS. I like to listen to the symphonies.

I do my own work, especially on these older cars. So I mostly avoid the expensive sessions with the dealers. And, while I have sync'ed a few dual carb setups, three sounds like a challenge I won't want to pass up.

Now to find someone who has that setup and wants a break!

Thanks, again.

Dave
 
I echo Bert

Assuming that you do not mind forsaking originality - the triple side draft is a hoot - and both real eye and ear candy [not sure one can say ear candy, but the sound is intoxicating]. I have found mine to be reliable but thirsty - maybe even more than the S38 in the M6, but for less than 5K miles a year - no biggie.

In these days of covering engines with large ugly plastic covers - the triple side draft setup is particularly attractive (as Bert mentioned) on a 3.5 - almost as nice as the S38 of an M6 (Bert) or the S14 (a chopped S38) in your e30 M3.

Both you and Bert have great taste in cars (as does everyone on this board) - but even apart from your e9 attraction. I would love an e30 M3 or a tii.
 
Gkb, thank you for the kind words....

that is quite a stable of BMWs you have there, talk about fine taste in cars.

Bert
CSiX2
 
I guess I should admit I also own a 66 Corvette coupe, too. Some would say the horde is a bit much. I would agree, but I just can't decide which one (or three) needs to go.

Dave
 
...if your going to do triple Weberss.....

go directly to 45s. My brother has had both 40s and 45s and the the word from our Weber Guru (he's dyno'd & dialed Webers on Ferraris, all six) is that the 45 are more tunable. We've raced them both 40s and 45s in his coupe, 45s give you more options. He's never had a cold start issue, but we're on the Calif. coast. The thing to watch out for is clearance from the stock brake booster, a Tii booster offers more clearance for the velocity stacks/carbs....ie: triple Webers create a Pandoras box...(lotsa $$ parts for best fit/most performance)
triple 45s need a fat header (Stahl) and high flow exhaust system to get best out of them...and a good dyno/Weber guru sesssion...on top of a real nice motor.

I'm currently trying out dual Weber 38s on a Hipo 3.3L with a mild header set-up. Just can't justify triples right now.....someday I'll have my triple 45s.................someday! :twisted: They just look fantanstic on inline 6s: BMW, Triumph, Jag, Aston Martin....just awesome!

-shanon
 
Agree with Shanon

Well, actually I cannot speak for the other Weber setups, but the
45s have worked very well for me (i.e. good performance, minimal hassle) and the PO did put in a Stahl header.
 
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