Thanks Cambo!

Walt

 

Just to complement, I don’t know the newer Ftype ECUs but I guess they work similar as the older 5.0 XKR Denso ones in how they control the engine output. There the ECU is not bleeding of the boost, it controls the torque with the throttle opening. So once you reach a maximum torque, the ECU will not further open the throttle (even though you press the pedal to the metal).

This is also why it was so simple to make ECU tunes without having much prior knowledge on 5.0 XKR cars, the XKR-S model had these torque limiters at a higher level so you could simply locate where these torque limiters where by comparing the maps

The Gearbox also control max torque, so for an optimum tune, ie get the max out of the engine, you would probably also have to tune the TCM.

 

Whoa!!!
That is totally different than what others have been saying previously. A bleed valve bleeding off boost vs electronically limiting throttle inputs may have the same end result but are vastly different concepts.

F-typical?
Cambo?

 

F-Type has the Bosch ECU, is very different to the earlier cars than run the Denso.

EDIT

If you have a look at the various discussions about tuning the XKR, it is mentioned several times.

Here's one:

https://www.jaguarforums.com/forum/x...38/#post844644

and have a look here too https://www.jaguarforums.com/forum/x...lution-122060/

 

The 5.0 SC cars do not have any mechanism to bleed of boost, there is only a vacuum controlled bypass valve, that’s it, so boost changes as an effect of controlling the TB. Next to that I found this myself by checking all parameters with the IDS so know it by a fact. This way of controlling power is actually already used since the early 4.2 cars.

 

Well i'm probably wrong then.

 

No, at most you have been misinformed by some who could have known ;-)

Sorry, I only wanted to compliment the posts already made, by giving some factual info.

 

That sounds like a normal recirculating system - boost is bled into the inlet before the S/C rather than to atmosphere. It should operate on vacuum, even if it isn't electronically controlled, to prevent the S/C providing boost to a shut throttle and blowing the inlet hoses off.

 

So, again I'm a novice concerning tuning issues ... if a smaller pulley is added to boost psi, something would also have to be done with this 'vacuum' system to make use of the added boost. Or looking at it another way, perhaps the existing super charger provides enough boost, however the 'vacuum' system could be adjusted so the engine receives more.
Anyway, interesting stuff ... but confusing to me at times as well.
Lawrence

 

Its a very simple vacuum operated system, that lowers the SC's power consumption at idle/cruise situations as it equalizes the pressure of the in and outlet.

 

The vacuum system has nothing to do with the maximum boost you can make, that was my point.

But that is on the 5.0 SC cars with the Denso ECU, I have no knowledge of the Bosch ECUs used. There could be changes in how power is controlled, although I would guess it is still the same.

 

Where are the before and after dyno graphs?

 

Thanks to everyone for the information.
I'm very interested in the your results of the Eurocharged tune in Houston as that is my plan after I get a little more education on the subject.


Thanks again everyone. Very informative.