Hallo !

I m new here and i have some questions for tuning my xjr6.
Please forgive me for my bad english i come from Austria
I already have installed a cold air intake, Andys brackets and custom dual exhaust system. I tested the jag on the dyno and it only had 280hp on the rearwheels, so i tested the loading pressure from the supercharger an it only loads 0,4bar and at higher rpm it falls down.


Now i have remanufactured and ported the SC and also bought a bigger lower pulley and i also will have a look at the bypass valve maybe there is the failure for the low pressure ??

And i also want to install a bigger throttle body, anyone did that before ? Andy Stodart told me that the engine is running rich enough no ecu remapping has to be done, i that correct ?

Thanks for your Help and Informations !

Greetings from AUSTRIA

 

Hi Austria


There is some good info about bigger throttle bodies in this thread; https://www.jaguarforums.com/forum/x...adapter-78096/


Seems like it´s possible to bore it out from the stock 72mm? to about 80mm and, of course, also have a matching blade made. If instead using some aftermarket tb you will have to arrange something different for the idle control.


I personally doubt that there is much gain with a bigger tb alone. Both the tb-adaptor and the air ducts have too much of knicks and bends. The square area in some sections are probably even insuffient with the stock tb. I have spent several hours on mine with files and sand paper rolls, trying to smooth and enlarge things but there is actually not very much that can be done. I think that, with a larger than stock tb, the only sensible thing to do is to fabricate some new tb adaptor and also skip the rest of the ducts.

Don´t know anything about the diameter of the air flow meter as I use a different system.


And, about your dyno power numbers; I don´t think that with your setup the 280 rwhp is that bad, should be equal to something like 330 – 340 hp on the crank, depending on type of transmission. Seems a little odd though that the max boost is only 0.4 bar with those numbers.


Best regards
Jan

 

Interesting topic. There are quite a few threads in some of the other model forums about bored/enlarged throttle bodies that a quick search turns up. Reactions are mixed, but one behavior they do seem to exhibit is "quicker" throttle response since at a given throttle position the butterfly is essentially open more.

Some found that quicker response attractive, others have not.

I have a TB for the XJR6 that was bored out by Maxbore, but I haven't tried fitting it yet. I had it fitted with the improved recall throttle spring when I had the R493 recall done last month, so it's ready to go. But that's a pretty low priority to tinker with at the moment.

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Hi guys

My dyno datas were 280 hp on the engine and 220hp on the rear wheels with 0.4bar Pressure from the Supercharger ! The higher the rpm the lower the pressure.

Today my jag mech called me , that a small part at the TB has been broken and at the bypassvalve also a part wasnt working. On Friday all parts will be installed in the engine. What do you think will bring me all tunings togheter ? Exhaust , Andys brackets , bigger lower Pully , Cold air intake , ported remanufactured Supercharger .