I am looking at options to improve drive-ability in my SII XJ6. I have had the car for a number of years and pretty much have stripped out all of the smog equipment. Currently running the twin zenith strombergs. I am looking to take it to the next level and am considering EFI options. Has anyone had any experience using a fuel injection kit from Classic Fuel Injection? http://www.classicfuelinjection.co.uk/ Any feedback would be appreciated.
Take look/search o the etype forum. there is a lot on this subject. The main work is in the fuel delivery/return and crankshaft position sensor assembly.
I would start with an S3 manifold and an aftermarket ECU. I’ve been running a 67 S Type on EFI for 20 years, check the archives.
Looking at the Classic Fuel Injection (CFI) website, they use throttle-body fuel injection instead of port fuel injection. Port fuel injection is what most people think of when they think fuel injection, and is the method Jaguar used/uses.
A throttle body injection setup basically injects the fuel into a central throttle body instead of the ports feeding individual cylinders. It’s kind of a halfway point between true port fuel injection and a carburetor. You might almost consider it a electronically controllable and tuneable, more precise carburetor. The only OEM cars I recall in recent memory using throttle body fuel injection were the GM models of the 80’s and part of the 90’s.
I believe the CFI configuration uses three throttle bodies for the XK engine, so one injector for two cylinders - just like a three carb SU setup.
Throttle body fuel injection does have benefits and is much less complicated than port fuel injection, but the potential capabilities are also correspondingly less. From my standpoint, I’m not sure I would just go halfway with throttle body injection, since I’m not sure how much potential gain (if any) there would be over well tuned SUs,
It might be a worthwhile gain over ZS’s, if the cost is less than an SU conversion. If close in cost, if it were me, I’d have to see what the advantages are before sacrificing the “OEMness” and looks of the SU’s. (not originality, since of course the ZS carbs were the originals.)
For sure, properly tuned port fuel injection would confer considerable advantage, though the difficulty and cost may be prohibitive for most.
Dave
Dave,
I concur with your statements on the advantages and limitations of a throttlebody set up. The CFI group would sell me a kit to use the Z’s but that seems to me like continuing the compromise, and they even advised that using SU’s (as throttlebodies) would yield better performance.
One additional advantage of the CFI conversion seems to be the removal of fuel from the bowls which undoubtedly will leak/weep.
Since the last time I posted, I’ve looked into a few other options, and found an outfit out of the UK that has manufactured throttle bodies to directly replace the Weber DOCE. The challenge seems to be getting it to all fit under the hood…
A number of years ago I recall reading an article in the Jaguar Journal about a guy with an XJC who installed a triple Weber set up, but to date I haven’t been able to relocate that article to find out how he made it fit.
I have fitted a “Classic fuel injection ltd” system to my 1968 mk2/240 it’s my first weekend out, and having driven 300kms i can tell you it makes your pussy purr like a very content cat.
i will always be disadvantaged due small engine size but the gains in smoothness pull off and high speed [running 5 speed w58 box] and every thing else made the leap to efi well worth it, i’m booked for the rolling road next month. i think i may not need it as the system has wide band O2 and learns it self. The simple thing about it is just fit the mounting blocks between the carb and inlet manifold.Longer studs are required for fitment and an extra inch distance for air box to move away from engine. Take a look on the site it show a xj6 fitment with su’s. Kevin is a great guy and very helpful. This option is so much cheaper to buy and very easy to fit. no more smell of petrol yay, no problem parking on hills and no hunting other parts ect.