Hi, Is there a mechanical difference between the DCNF QV's and the K Jetronic QV's? Searching the inter-webs is indicating different cams and compression ratio. I could appreciate the 35hp loss due to the mechanical airflow device of the K Jetronic system. Any information you can supply me with will be much appreciated.
What you found is correct. Compression ratio is a bit lower, and the cam timing is different, and the exhaust manifold is different on the FI car so that it could pass the emissions rules. Otherwise, they are the same. But to make US car into a euro car, you need six carbs, six intake manifolds, 12 pistons, four cams, four headers, and associated hardware. Imo, the easiest way to get most performance bang for buck back is to start with the exhaust. 1) Put euro headers and an Ansa sport, or aftermarket exhaust. Now you are more than half way there. 2) The next best non-aftermarket increment is the cams. This step is expensive though. Well hack, just add an aftermarket ignition to gain some more instead! You can leave the FI in place and with cams, ignition, and exhaust you are almost all the way there. 3) Changing the pistons is not worth the trouble imo because you have to basically disassemble and rebuild the motor from scratch, plus buy the new pistons! This is only worthwhile if you have a blown engine to begin with. My advise to FI owners that want more performance is to change the exhaust first, then when it is time to do a clutch, add the euro headers. Then stop there! You have most of the performance loss back, and you haven't spent that much more incremental money, and you have the fuelie reliability.
Ditto, I just put a complete Quick Silver header and muffler system on my FI. What a difference in sound. I am sure that I gained almost all of the 35HP back. Headers can be installed with engine in place.......with patience Even without any HP increase the sound is worth it alone!!
Thank you both for your responses. What are the major issues with the FI cars? Has any one had success in converting to efi, to remove the K Jetronic system, is there much of a difference in power? Thanks again!
K-jet is a very dependable simple system that was used on millions of cars back in the day. I have heard of conversions to more modern EFI & distibutorless ignitions, but (I thought I would never say this in my life time) the car as it is, is fast enough for me.
Thank you all very much, I now have a greater understanding of the QV's DCNF / K-Jetronic differences.
+1 Lots and lots of information available on the K-Jetronic systems. When you think that system was used on Mercedes, Porsche, BMW, DeLorean, Saab, Volvo, Ferrari, etc. back in the day, there are plenty of spare parts (and expertise) around. The key is to look at the BOSCH part numbers and cross reference it to a more "popular" car that used the same parts. For example, Lamborghini wants $235 ea for the fuel injectors. And yet you find the same injector was used on Mercedes 190, 280, 450 series and can be bought for around $25 each through places like Rock Auto. I think most here would agree that regardless of having a Fuel Injected car or the DD car, the biggest Achilles heel is the Marelli ignition system. Almost every Countach 5000QV that I looked at before buying mine had swapped the Marelli box for the MSD 7AL unit. Raymond has a great write-up on this from DD perspective on his site: Lamborghini Countach #GLA12997 MSD Installation BOSCH has a great technical resource manual that is all over the Internet for free (I've attached a copy so you don't have to hunt for it). Its a very nice overview of the system and the function of each component. Mike Image Unavailable, Please Login
There is actually a big difference in the cams. K jet just will not tolerate much overlap in the cam timing so it had to be done. I have not done dyno testing but in my opinion it is far more than a 35 HP difference.
