Econo Jag MK2 1967 2.4 Auto

Looking lovely.

At least nobody can claim the mascot will cause injury to pedestrians!

Good luck with the move.

I've arranged for the car to be moved from my mums house next week into its new home, hopefully all will go smoothly and I can get on with it again.

One thing i've been thinking about over the past few months and the Temptress thread on here ivanhoew has made me thing about even more is whether I could turbo charge or supercharge the old 2.4 XK engine, I know they aren't the best engine in the world but for me thats not the point, some cheap power would be good and I think they are fairly unstressed as the bottom end is the same as the 3.4 and 3.8 engines which have nearly double the power.

The issue is where on earth do I start, how do I know what is best for the engine, what would I use to control the fueling, what size supercharger or turbo (or turbos) would I use?

Its probably all just pie in the sky given my budget but it certainly sounds interesting and something that is very rarely done on these old XK engines.

It could be a fun adventure to add either a supercharger or a turbo to your XK engine

But, if you e not dabbled in that type of tuning before the learning curve will be very steep, just as it is when people who do modified car tuning stuff try to turn their hand to rust repairs!

Turbo and super chargers both have their advantages and disadvantages. Very broadly speaking a supercharger will give you a more instant response and work right from low revs, but as it uses engine power to drive it and that power requirement increases with revs, the top end power increase isn’t as high as the midrange and it’s not as fuel efficient. Turbos on the other hand will take a certain amount of time to ‘spool’, and at low revs will not make any boost, but their parasitic losses are much less meaning you can keep making that power further up the Rev range.

You also have to consider packaging. Super chargers require solid mounting to the engine with sturdy brackets and the front pulleys and belts on the engine need to be reworked so they can drive the supercharger. The turbo mounts just to the exhaust system, but you need to make the exhaust manifold and down pipe mate up to the turbo. So it’s potentially different types of fabrication skills needed.

I don’t think twin turbos would be wise for a first attempt. Twin turbos are used where packaging makes it easier (v6 / v8) or because two smal turbos can offer a better low down response than one big turbo. With your straight 6 layout you could do either, but the plumbing for one turbo would be much much simpler.

Turbo manifolds can be made from mild or stainless steel. There’s various approaches. Often steam pipe sections are used for DIY custom manifolds, as they are very thick wall and come in nice handy bends, T shapes and straight sections. See this example of a kit you can buy to build a turbo manifold for an mx5 to see the kind of bits you need and how they assemble into a simple ‘log’ manifold. bofiracing.co.uk/brands/davefab/davefab-td04-log-manifold-fabrication-kit-for-mazda-mx-5-na-nb/

You can also repurpose sections of your original exhaust, if it’s suitable shapes. Lots of the v8 guys simply fit their exhaust manifolds upside down which instead of then pointing out down and behind the engine, now point up and forwards, you can they cut the manifold off after the collector and you’ve just one pipe to join up to wherever you want to locate the turbo.

Regarding fuel and ignition control, forced induction can be done with carbs and distributer controlled ignition, but it’s often a compromise resulting in poor cruising performance and also does not maximise the available performance. I believe if staying with carbs then superchargers are a more tried and tested route.

Home build EFI (electronic fuel injection) can be a really interesting and enjoyable project. But it is not an easy project and it is important to have ( or be up for learning!) a reasonable grounding in basic electronic theory otherwise you will find yourself blindly following guides with no idea why you’re doing something or how it will help.

Megasquirt and Speeduino are both affordable home built solutions. They are available as a ‘solder it together yourself’ kit, or you can buy prebuilt units. Speeduino is cheaper and seems to be growing a bit In popularity, but megasquirt ultimately has more flexibility to run unusual combinations of engine designs and different components (different types of coils / injectors /etc). Megasquirt also benefits from good detailed manuals and documentation (www.msextra.com) and active forums where you can ask questions and learn.

There are of course other EFI solutions, which are much more ‘plug and play’ but they tend to come with a much larger price tag!

Installing the ECU itself is only part of the battle, you will also need to consider the new sensors needed to tell the ECU what the engine is doing (crank position, throttle position, air and coolant temperatures, etc) along with the outputs from the ECU, so coils and fuel injectors. You will also need to a range high pressure fuel to the injectors, which might mean using a swirl pot or converting your old tanks to have an internal swirl pot.

Finally (and this is the part that takes the longest) you need to learn how to actually tune the ECU! Again there are lots of guides and information out there online. The principals are simple, actually getting it working as smoothly and perfectly as you’d like is another matter!

I’m not trying to put you off, far from it, I’m just trying to lay out what’s actually involved in ‘just going fuel injected’ as often I think it’s glossed over and peoples expectations differ to the reality.

If you will enjoy the project of figuring if all out, the challenge of debugging the system and chasing down the wiring issues that’s giving you false reading on sensors, or of going for drives taking data logs and then revising that information and updating your tune to make the car faster / better, then you’ll find home built EFI great. I certainly enjoy it.

if you just want a car that works and you don’t like wiring, then possibly a swap to a 3.8 xk engine would be better!!

i just bolted to the original cast manifolds, no welding .










re carbs , not sure , with the metro turbo su , you have a box bolted to the inlet ,fed with boost , and there is a single connection to the float bowl breather connected to this box so boost wont simply push fuel out , also there is a bit of fun and games getting the carb needle the right shape to be correctly fuelled .

what GNR says above i agree with ,although a turbo can be made to respond at any rpm , if its sized to do so ,eg on the temptress the turbo is sized to work from low to mid range rpm best , for max torque .

it will tail off a bit at max revs but thats fine for that car .


re ignition , cheapest ,i would take out the mechanical advance mechanism in the distributor ,and run fixed timing around 24 degrees , and play with it , leave the vacuum advance on ,and live with that compromise , its way cheaper than mapped ign ,and will work .just not ideal . obviously this depends on your compression ratio , fuel octane ,and boost level.


regards
robert

Ah, with that experience then you'll find Megasquirt or Speeduino a walk in the park. They are pretty simple as far as control systems go, essentially just some simple analogue circuits to condition the inputs and outputs from a microcontroller.

There are calculations you can do on the air flow of your engine and then you can plot that against the compressor maps of a turbo. That is the arithmetic approach to turbo sizing, and will allow you to see where in the rev range the turbo will be working most efficiently. I've got the calculations in a book somewhere I can dig them out if you need them.

Equally, as ivanhoew says, a turbo correctly sized for 250hp on one petrol engine will be broadly suitable for 250hp on another petrol engine, especially when you've a moderate power goal at moderate levels of boost. If you're looking to run big power from a big turbo on a small engine, then finding a turbo thats perfect is more important.

A blower would probably be easier but a Turbo would be more...fun...

With GT35 and 45 being so cheap I would buy a new one.

www.ebay.co.uk/itm/312835251333?_trkparms=ispr%3D1&hash=item48d66f1c85:g:GrgAAOSwUJNdwRqH&amdata=enc%3AAQAGAAACgPYe5NmHp%252B2JMhMi7yxGiTJkPrKr5t53CooMSQt2orsSB0Xm7k0guzAysaIMfJcbBNtrUD0UDWllM4y8BAF2agpz3mUEW4yHkESRrqf4uR0AP1nejf0hh8cr%252Ba1zEcqVeXs7O9WTaAaP6kC6MCT8TvpEt3I8pb50%252BlsZ0WIfCj0KtIZ1oMu2%252BRJFAnxkdHRjg%252BLsruq8DqYZvtbCdkqxTByFGjfzCxd8sRw7wm7G2yY4oVAqZGEvh701rOIO9vbfVCmTrk72xHp9%252BK8nHtWOy7tHQsLYpwnsZYcBxuovhEpP67OV%252BUMKxet4bb02x7li0kYfflCPsUM%252BjQk1TOppWWfTXF1eX%252BdA6Oq3MIkiNSNY6nGpOsraQrZtE5jOvUtZntqLea7Nfwzf%252Bq6O2eHPtNYKp3BN61I5wwfbk2gREGRCTYY5%252BsayEqXaVqqBCLfpyyQ%252FJH1zn2b3l%252FfcDagxk9Dy%252B%252FhMzJAJlX%252FGe%252FesBGHzolxQCDsdW%252FH%252B%252BgFK7KZorFUqgojHHVsBA8xC5L%252FZDjtaL6zrL8jor2eddPEMh0Wy9UPnOQNUwfs6tcCIh%252BTCEy13MZ7SSe%252F%252BLa0diL%252BYH%252BbU8lRC1pdLpOm2q4DCqZZQGnjY7RfOTILZF6oQmCwSC6Ie3RzoDH1FewtrXlOxkJGayQjwuIsLZVPIufjQNlOHzvTHsvY2oY7kHRE7mxGYQwPHmbBBJTkN3VXg%252By%252BlPqP6s5OFVIRTujh3N0827SQ3oVoaxoYtkmMJ9IXm1SUimCejkb73g93pKscRizL5E1v2ZAmfeeUg982GM7tyBU%252B%252BIPSkUC%252BaGM%252Bu%252Bi8tKV7b%252FNKzxxkuiZiAo7T3jjE2tbs%253D%7Campid%3APL_CLK%7Cclp%3A2334524

There is so much information on YouTube now a talented man such as yourself should have no trouble getting into trouble...

My main concern would be is the gearbox upto the increase in power.

What ever, I would love to see the addition to the rebuild.

P.

I used citric on all the parts of my last motorbike build. It works great. I found 2r hours soak, remove and give a light wire brush, give them another 12 to 24 hours and brush/rinse. Even on badly rusted and pitted parts I ended up with shiny steel right into all the nooks.