3.0CS versus CSI

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65gtfastback

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I am in the US and interested in a 3.0. I understand the mechanical differences of carberator vs fuel injection but I am wondering if, in reality, there is any difference between the cars in terms of power / driveability.

Can you tell the difference when you are driving a CS versus CSI? Maintenance-wise, I assume that the fuel injection will be less of an issue than trying to keep the carbs in tune. Is that true?

My preference is a CSI but I wonder if it would be easier to find a CS here since the CSI's were never imported by the factory.

Any other considerations?

Thanks
 
I have never owned a carburettor version of the E9, but I would imagine that you could tell the difference when driving as the CS has 180 hp whereas the CSi has 200 hp.

Having owned a CSi and now a CSL my experience with the D-Jetronic system is that is actually works very well for an analogue system once it is adjusted correctly :!:

Put differently the injected engine can be a pain to troubleshoot if you are having problems. Once it's all correctly set up don't touch anything and just enjoy the engine :)

I can't speak to the ease/difficulty of adjusting a carburettor engine, but I'm sure plenty of other people have first hand experience with this.

In the 3 years or so that I owned a CSi, I never had to touch anything on the engine setup ... and that car displayed some of the best cold start capabilities of any car I have ever had .. you could start it on a very cold day and drive off without any signs of hickup or anything just like you would in a new car :)

Personally I would most definitely go with a CSi over a CS if possible, but as you point out the CSi is probably more difficult to find in the US.

There are plenty for sale in Europe, but the good ones are expensive ... as they should be 8)

Have a look here http://suchen.mobile.de/fahrzeuge/s...eation=&damageUnrepaired=NO_DAMAGE_UNREPAIRED
 
I owned a CS before my current CSL. There is a noticable seat-of-the-pants difference between the two, with the CSL accelerating faster - but much of that could be the weight difference, as the CSL is truly bare bones.

I live in London, and never had any trouble cold-starting the CS. The carbs were well tuned and balanced, idled smooth and had no flat spots during acceleration. It never felt underpowered.
 
I can only compare my carbed E9 vs my injected E24. The experience
is a bit different but I wouldn't say better or worse (other than in mileage).

The E9 starts and idles great, even better than the E24 sporadically
hunting for the right RPMs. Both are about the same power on paper
but the E9 is happiest between 60-80MPH, while the E24 wants 80MPH and
above. This may have to with the car itself not the engine so much.

Before rejetting the Webbers the most noticeable difference was that
the E9 wanted to either accelerate or deccelerate but it was not easy
to baby it at constant speed around town, while the E24 can be placed
at any RPM/speed. That has been sorted out but took a while.

Oh, the other carb idiosyncracy is some dieseling sometimes when shutting off the engine. I heard it can be cured, and I heard it cannot.

The best reference is Shawn who converted from carb to F.I. on the same car...
 
carbs

Getting your carbs set up right/jetted corectly is key.

For the longest time, driveablility in my coupe around town with my dual carb'd set up was challenging. Coming off and on throttle resulted in hesitations and bucking. In the upper revs it was fine.

This past Spring, Mario played with the jetting a bit and the around town issues are now gone and the off/on throttle response is fine. We still have some work to do to ring out remaining performance.

The trick is to have someone who knows carbs go through the setup process with the jetting and the linkage. Once you've got the right setup dialed in, you should be fine with carbs.

That said, fuel injection (if set up right) requires less fiddling and will probably provide a bit more power over some dual carbs and an improvement in mileage.
 
Keep in mind that he's asking specifically about the D-Jet injection which is very different from Motronic. My experience with the D-Jet has been mixed. D-Jet is an analog system, so much of it runs on various resistance sensors which get old and start acting erratically (think about the symptoms when you have a bad fuel level sender -- sometimes it works and sometimes it doesn't. It operates on the same principal as the D-Jet throttle position sensor). When the D-Jet works, it works well on a stock motor. The problem is, even the newest original components are now at least 32 years old. Most of the stuff is still available new, but it can be hard to find and really expensive -- for instance, a new manifold pressure sensor runs about $700 -- and the car won't run without it. The distributor is also a one-off which is impossible to find. Don't think you can just swap in one from an L-Jet car.

That said, a well-sorted CSi is a bit smoother, faster and has more torque compared to a carbed 3.0. The CSi came with higher-compression pistons and the 3.25 diff makes for a nice highway cruiser. Other than that, they are pretty much the same with the exception of the fuel delivery system. If you want a stock example and intend to keep it that way, I would not hesitate to get a CSi. If you are a tinkerer and you think you'll be adding a cam, headers, 3.5L motor, etc., then I'd opt for a carb'ed version since the D-Jet isn't really able to compensate for any modifications to the flow of air into or out of the motor. Unless you really understand injection systems, you'll be asking for trouble if you try to run the D-Jet on a non-stock motor.

When I did my 3.5, I removed all of the D-Jet parts and carefully packed them away for a rainy day. I converted the whole system over to a GM-based ECU and sensors with fully programmable fuel and ignition control. It can compensate for the internal engine changes, looks nearly stock and actually works very well. Of course, I have about 200 hours of R&D and tuning wrapped up in a custom, one-off system, but it works for me.
 
One of the most valuable additions I have ever done on my twin 38/38 weber set up (and this would hold true to any carb engine) is a wide band 02 sensor that gives a real time indication of the air/fuel ratio. Huge asset in getting the most out of the engine and improving overall driveability. Several good units available such as

http://www.wmsracing.com/pgi-CustomListProducts?Wideband O2 Sensors,2,1,=,wms-wbs@

In all likelihood FI will out perform carbs on the street but if Andy is right about the D jet/engine mods, the carbs allow a more user friendly platform to work with. I like what Andy has built up for his FI solution - might go that way eventually.
 
Carburettors vs. Injection

Either model, when equipped and tuned properly, should provide a similar pants-o-meter response.

This topic, like so many others, is impossible to answer, given so many variables, e.g., typical driving style (mixed traffic vs. WOT on the Autostrada). Is the poster more interested in tractability? Ease/Cost of maintenance? Top Speed? 0-60 Acceleration? Fuel economy? Each of these considerations are trade-offs with each other. Maintenance was specifically mentioned, but given the varied history of each 30+ year old car, it is impossible to say that one car will require more maintenance than another. Obviously, carbs tend to be simpler and it is unclear what the useful life of any of these fuel delivery systems is. I have a DJetted coupe that runs fine, but I am afraid to move some of the original wiring under the bonnet due to its becoming brittle.

But there is rarely an "all-things-being-equal" comparison here.

No one has mentioned the fact that the Csi uses a tall 3:25/1 rear axle ration where the Cs is much shorter. And how about the difference in compression ratios? I have never taken the time to confirm this, but I have been told by a few 2800Cs'ers that their flywheels may have been lighter. This may cause an entirely different set-of-the-pants appraisal of the two models. :lol:
 
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