Does anyone know the specs for XJR (AJ27) fuel injectors? The flow rate in particular...

 

yeh, see here for full breakdown
https://www.jaguarforums.com/forum/x...-photos-70199/

 

Would be interested too in the XKR/XJR injector flow data, I can only guess, and would think somewhere between 450-500cc or so.

 

Sean, thanks, but that data is from n/a engine.

Avos, does your XKR have original injectors?

 

No, am using the 4.2 injectors now, but you can get pretty far with the original injectors, especially as you can also up the fuel pressure.

But what is your plan?

 

I'm trying to figure out what it would take to convert to E85... it's 1€/liter ($5/gallon) while regular gas is 1.7€/liter ($8.5/gallon).

Good read on the subject (some stuff is Volvo specific, but most is relevant to all cars with electric injection): Converting to E85 (ethanol fuel) - Turbobricks Forums

 

Be sure to use E85 certified fuel pumps. E85 is hard on component materials.

 

Some tuning is also required to get it right (let me know if you go this path, I can help you maybe with a tune), so there is some investment to be done including injectors so they match the MAF signal. As you lose efficiency, you also need more E85, so the price difference becomes smaller.

Am not sure if the stock fuel pumps are able to run E85 (don't think so), they might just be able to handle the extra flow. You can find higher flow pumps that can handle E85 pretty easy, so better to swap them out.

 

I've made calculations of fuel costs based on an estimated 30% increase in fuel consumption, and with current prices I would still save about 1,000€ per year with E85... I'd be happy if I could get away with just replacing fuel pumps and increasing fuel pressure. Injector swap might make the conversion too expensive.

ECU tuning is required to take full advantage of the new fuel, but that would mean that I couldn't use regular gas anymore..? And while E85 is available where I live, the same doesn't apply for most of Finland. Not yet anyway.

 

I thought you would lose more efficiency, especially when you don't change you timing, so better check again the calculations if you are not going to change your ignition timing.

I think you must make a choice for either E85 or normal fuel, as for one you would like to have the ignition optimal, and you don’t want to change your fuel pressure manually all the time based on which fuel you put in your tank (not even thinking about calculating a mixture of fuels).

Not sure if there are piggyback systems available that can identify the fuel type (and mixtures), so to apply the right ignition and fueling, but I think you need to investigate that more.

 

A piggyback system that would sensor the amount of alcohol in the fuel line would be ideal. That would make it a true FFV/flexifuel car. Might be pricey is such a system exists.

For the moment I'm still looking into how the injectors and factory ECU can handle E85. If your estimate of the injector flow rate is correct, then the injectors should be ok. I'm planning to have them professionally cleaned and tested, after that we'll know for sure. This won't happen very soon though, as this means the car will sit in my garage without injectors for almost a week, and it is still my daily driver...

The ECU should adapt to E85 by increasing the long term fuel trim with E85, right? It may of course hit a limit in the adjustement, and go to restricted performance mode. Another thing is what happens in open loop situations. Any idea whether LTFT is applied at WOT in these cars, or does it just go to a default/fail safe fuel map (which may be too lean for E85)? An E85 conversion kit (increases injector open times) would of course help here, and would cost maybe 200€.

 

You can also increase the fuel pressure if it would be just not enough flow when using the kit to extend the injector time. But you still have the issue again that you need to either 1 type of fuel only.

There is some room with respect to the fuel trims, and the ltft values will be used in open loop, that’s what they are there for.

Here is a thought, let’s say you need 30% more flow with E85, then you could for instance increase the injector timing by 15%. This will be too much for normal fuel, and to low for E85, but the can be just within the limits for the ECU to correct. The borderline there is -20% or +20%. But you need to have everything working properly (best to use a new MAF also), so your fuel trims at stock condition are close to 0. This way the ECU will automatically adjust to the mixture of E85 and normal fuel, but it will also need its time before it is adjusted, so not go shock wise from 1 fuel to the other... This requires some careful tests though as you need to tune it all so it souts the ECU / fuel mixtures best.

As you are not going to tune your car, you could already advance timing with your ECU, I would say about 2 degrees, that will help a little...

 

There is an adjustable E85 conversion kit that allows you to do just that. It also has a few presets, so you can change between fuels by pressing a button if needed.

Bioadapter E85 conversion kit

 

Had a quick check, but you need to preset the unit. The automatic mode will work based on the O2 sensor input, but don’t forget that our ECU is doing the same thing which you can't turn off, and having 2 ECUs trying to adjust the mixture is something to be wary off!
Good luck though.

 

Actually the automatic mode on that box is not automatic at all. It's not connected to any sensors, it's just set to 20% increase (by default) and lets the car's ECU do the rest for different fuels. Just like you described in your earlier post.

In other words, it has four presets that you can adjust yourself. Personally I'd tune one preset for E85 so that the LTFT stays close to zero, one for straight gasoline, and two somewhere in between.

 

I've done some googling of E85 usage in charged engines, and I've seen cooler air intake charge listed as a pro-E85 argument in many places... I wonder if there's a temp sensor in the XJR that would show the temps in the intake manifold so this could be verified? The IAT that shows up with an OBD2 scanner is probably the one at MAF, because it shows ambient temps soon after the car starts moving.

 

Regarding cooler intake air charge, I don't see how this can happen, as the fuel is injected just before the inlet valves. It would make for a cooler charge in the cylinders, more air/fuel, and possibly more advanced ignition timing.

Pete

 

Buckhead Imports has a 550cc injector kit for the XJR/XKR. The stock ones i beleive flow about 440cc.

 

Where? I don't see them selling anything for Jaguars on their website.

 

I purchased the 550 injectors thru Buckhead. If you call speak with Tony he is the person I dealt with.