Some people like mi loves his XK8 and don't want to replace them with XKR even if they need more power. Unfortunately there iwas not much you could do to have more power in xk8.

I have found the solution. The soft-turbo (low pressure supercharger) is the answer.

At the moment my car is much stronger and what is the most important I have high torque at very low RPM.

The engine keeps high, original compression rate and it`s charged to 0,39 BAR.

Before:

After:

Please visit my web page to see the full instructions how to do it. It`s a step by step guide. Unfortunately at the moment there is only Polish version but you can use google translator... There is a lot of pictures so you can understand some just with watching them. I`m working on English version!

Ps. There are also my another projects and interesting informations about XK8 and XKR.

If you have any questions, just ask!

Marcin, FISHMAN ;-)

 

It looks as if you swapped the entire engine. Anyway, congratulations!

 

If I had a hat on I would take it off to you.


Not many people have the kahunas to do what you have done

 

after translating it im still alittle confused. im excited for the english version

 

Fantastic, Great Job!

 

I would think that there are a myriad of other changes needed in the engine internals/externals to accommodate the extra heat and power that will be generated.

Doug

 

Fishman has choosen wisely (imho) to go for about 6 psi of boost instead of the 11.6 for the supercharged cars. This means less thermal load and less power needed from the engine to drive the SC.

The SC engine needs about 60 hp to drive the Eaton at 12000 rpm and 11.6 PSI, and assuming fishman is running about 8000 rpm max at 6 psi it would cost only about 20 hp.

Also the discharge temp is much lower, on the SC engine it is about +200 F, whereas with 6 psi it will be more in the +100 F region.

 

Bravo ! Never say never.

 

I'm fluent in Polish, and one thing I noticed was that he said he had to add some type of second ECU to make everything work. I guess the standard ECU doesn't like the boost. I wonder how the second ECU interfaces with the first one. That seems like it could be problematic.











By the way, in addition to Polish I'm also fluent in 51 other languages.
http://www.google.com/webmasters/igo...le%20translate

 

Hi,
Avos is right, but not in 100%.
I`m charging just 6PSI and that of course means that the supercharger runes on much lower rpms. That means that I`m loosing less energy to spin the charger. That also means that the charged air is less hot and needs less cooling!!!
BUT!!! My engine has compression rate much higher than XKR. Some XKR`s has 8.9 some 9.1 mine has almost 11!!!! That means that you can not compere Power coming from 6 PSI in my engine to 11.6 PSI in XKR with much lower compression. So power and heat coming from my engine is much higher than would be from 6PSI XKR!

My idea was not to go for max power. Other wise I would go for XKR and I would do exactly what AVOS did! But now my xk8 is almost as good as XKR what is enough for me and the fuel efficiency on 10.7 compression rate is much better than original XKR.
It`s hot and I`m thinking about changing bonnet to XKR`s or find another way to cool down the temperature under it. The rest of cooling system comes from XKR what you can see at my web page.

I was trying to use different supercharger. Much better one! It was the new Eaton TVS. The Audi S5 is using it! It would be perfect for 6PSI bust. Takes much less power to spin and better efficiency - less hitting charged air. Unfortunately I was not able to make the conversion to connect it with my engine. I guess AVOS would do it ;-) This model of charger but a bigger one is being used in new 5.0 supercharged.

Quote:

Originally Posted by Reverend Sam

I'm fluent in Polish, and one thing I noticed was that he said he had to add some type of second ECU to make everything work. I guess the standard ECU doesn't like the boost. I wonder how the second ECU interfaces with the first one. That seems like it could be problematic.

I know, i`s just a translator but it halps a little doesn`t it?
I did mansion why I`m using Piggyback unit. It`s not about the bust. I just used fuel injectors from XKR and the original XK8 ECU doesn`t know about it. So the fuel to air ratio has to be fixed!! And there is no problems with electronic at all......

Arther way would be to use XKR original Ecu which I do have, but I can not find anywhere XKR MAP sensor!!! I don't want to spend hundreds of $ to buy a new one. I`m not sure how it would work if I don't want to use EGR. As soon as I get the MAP sensor I will try with XKR ECU.

Does any one knows if XK8 has speed limit set to 155 miles? I was trying ones and it was my max. Or I had no time enough, or power or the speed limit... Any way it was too fast for my poor suspension. In 2 weeks I`m planning to change this situation. I have already Paramount springs, Bilsein HDfor back, Koni Sport Special adjustable for front and all new bushing, upper mounts and......
After replacing it it should be fine ;-)


Let me just translate the my web page and you will understand everythink.

Br, Fishman.

 

All XKs are limited to 155mph, unless desrestricted through mapping or you have a XKR75

 

You can't mix ECU's I am afraid, it will not work together with the Transmission.

When you have control over the mixture, you could try to do the same as the XKR ECU's, and that is to make it richer under load. This is more of an insurance and will help cool down the charge even further. Another feature on the XKR ECU is that it measures the air temp after the intercooler, and it will retard the ignition in relation to the temp. So it would probably be good to review the current timing, and maybe move it more to a safer value under load.

The hood vents are there to help the airflow thru the radiators, so would be a good thing to add, and it also looks better imho.

 

Regarding the transmission you can be right but I`m not sure. The transmission has separate module and I guess the ECU is sending the same info in both cases.

I don`t have any problems with Air to Fuel mixture. I did exactly as you said - more in high loads....
Regarding the timings I had no time to play with them and they are based on temp sensor next to MAF not the one in intercooler. I guess they are aggressive because of it, but I don't have problems with knocking so far which is GOOD ;-)
My extra computer is able to take info's from temp sensor in intercooler and base on it correct timing advance but I just had no time. I`m working out of my country and I`m spending just few month in Poland. To make this project it took me around 2 month almost every day. Keep in mind that I wasn`t car spec. Before this project I was reading and preparing my self for another 2 month.... Now you understand why not everything is perfect finished!

The bonnet from XKR is much nicer but imagine how nice is to stay next to XK8 on the traffic lights and with out any notice just disappear as a slipper... .

 

Don't get me wrong, I merely want to provide info for you from what I have learned so far as a headsup, I think you have already done a great job.

 

how to delete post?

 

No it`s all fine. Thanks AVOS for discussion.
Your advices are fine...
Thank you.

 

I have one problem and I need your help. May be I should open new thread.

It looks that my breaks are not that strong, not that sharp as before. Looks like the servo doesn`t work properly!
As it`s know the servo needs underpreassure to work. With supercharger situation is a little different. Especially when you push gas pedal to the flour and then suddenly you press the break! Then the bypass value is being opened and in my opinion a kisc of the air pressure can go to the servo...
I`m not sure about it but my breaks are not that good like before supercharger.

So is there any difference in breaking system? Is the servo the same? Does the pipe between servo and manifold is the same or has special valve in XKR.

Br, Fishman.

 

You probaly need a check valve, the brake servo normally works on vacumn. And now you have introduced boost. Some one else who has a little more knowledge will either confirm or set you in the right direction as I am fairly new to the Jaguar set up.

 

I doubt there is any difference between the 8 and R, and am sure there is no check valve or anything like that. Better to double check the vacuum hose, that there are no leaks or that it is folded somewhere.

Once you close the TB, vacuum will be build up which is also needed to open up the bypass valve. I beleive the excess boost will be gone quickly into the engine, and I doubt that the left over boost in that short period could have an effect (although I suspect some different with the NA engine due to the camshafts). You could attached a vacuum meter to get a real idea.

 

I've moved the posts regarding the LR3 S/C conversion to it's own thread, you will find it here ==>> https://www.jaguarforums.com/forum/j...ersion-145327/