Hello everyone!

Im new in this forum and a new jag owner so I would like to introduce my plans.. I'm from Finland and my english is not the best but at least understable. I know that in my plans I'm taking a quite of a challenge since nobody has really pushed its XKR nor STR this far in Finland. Someone needs to the first and I'm ready for it....

So this story started when I was looking for a new RWD hobby car where I could get 650 ehp out and after doing a thorough study and reading the thread by Avos about TS supercharger I decided to by a jag instead of M5/M6 or E55 amg, Another key reason for this selection was that S-type is considered more as "gentlemens car" and nobody actually realizes that it has some real power in it... So building a furious sleeper is my goal and before dynoing 650 ehp I will not quit.

So last week I went and bought a 2003 STR with 172 tkm on it. The car is stock but the previous owner had put quicksilver rear mufflers in it so the sounds are guite nice.. Eventhough we have lots of snow and ice I was able to get the feeling of the power in the engine and even with my "*** feeling" I thought that the car is missing some horses..

So I decided to start by getting a baseline dyno and the results are attached. 338 ehp and 553 NM.. This is apparently quite normal for worn supercharger and stock engine with those kilometers... SO now I only need to "double the power", not bad..

First mods are going to be following: (this will be my prioritylist in mods as well)
- Quaife LSD (who idiot builds a car with this power without a LSD?) (quotes asked for TL jaguar and paramount performance)
- H&R lowering springs (ordered)
- Avos TS kit (to be ordered after getting knowledge in the capabilities of surrounding components such as IC's and the extra potential to be gained by using e85 fuel.
- Exedy 600 whp kit for 6HP26 tranny
- E85 fuel and 700+ ehp?

For achieving my goals I need lots of your help, for sure. So I'm extremely glad from your answers in this thread. I'm here to push the engine to the limits and share my experiences.

As a starting point I would need to understand follwing things better:

1) What is the capability of these water cooled IC's? In the dyno we tested those and they worked fine since a quick acceleration and a "slow one" gave similar results.. In this case the outside temp fed to engine was -26 celsius so in those temperatures allmost everything should work... In addition I know that TS lowers the temperature of the pressured air in the cylinders but has anybody measured the difference in TS system with 600 ehp and the stock one? This is a key thing since too warm pressured air in the engine kills the engine by resulting in knocking and other issues... Going further with E85 fuel does not make any sence before the manifold air temperature with higher boost levels are in control as well...

2) How much the pistons, crankshaft, con rods and bearings can handle? Have you done an engine rebuild in tuned engines? Are there better bearings, pistos and rods available? Of course custom made but some other options..

3) Engine management? Avos has gone very far with stock ECU so it means that there are some extented capacity in that ECU after the stock maps end? Eventhough the original ECU has potential, I believe that optimal results are gained by doing a custom tuning to optimize the selected boost to maximum spark advances for each revs and boosts. Then of course designing optimal ignition retarding for higher manifold air temperatures is critical for avoiding destruction.. Has anybody used third party ECU in STR or XKR? Does anyone know how much the stock ECU retards the ignition advance in open throttle situations because of heat or knocking?

These are major things still open for me and I highly appreciate your help to get started to the right way in this project.

-Tama

 

My understanding is that the factory front mount intercooler and charge cooler water pump Need to be upgraded for the str once you up the boost from standard with eaton roots m112 , so the upgraded intercooler and pump should be sufficient and complement the cooler running temps of the T/S Blower!
Also I think you will struggle to beat avos for power in the Str as the limeted space in the the Str engine bay limits the possabilatys of the greater flow that xkr has !
As from factory the Str is 20hp down on the xkr for this reason , as the xkr charge coolers
Have inherently better flow (no 90• bends in the intake side or charged air side).
I think avos even states some were on this as well !
Cool t/s kit thou snap one up wile you can I say
And power to you!!
As for the stand alone Ecu it's a no brainer if you are looking to push the limits ,
You will be tuning within a few HP of destruction an after market ecu will certainly be more simplified and faster to get results as factory ecu is self learning witch will = delayed results. All so there are some cool ecu's around now that sence and know how mutch ethanol is in the mixture and map them selves accordingly ! Safe option I recon
But don't know how you will get the trans to comunicate with the engine !
It will obveastly be way Easier to just run with factory ecu and just let it learn plus you'll
Inherently gain the torqu limiting controll from your tranz to look after and protect itself from itself ! Good luck with this keep us informed. Cheers

 

Thank you for your answer!

I know that the air intake needs to be as smooth as possbile but I really do not think that some bends in the intake are restricting anything.. If thats really the case and I cannot fit big enough air intake I have a solution in mind for that as well. That solution and parts are attached in this post. And if needed, I will do it.

Going with the standard ECU is of course the easiest way but I would like to know how close to optimal can I get with that and how much it retards the advance in different cases.

-Tama

 

Ask avos - he has tried various things and at least may save you time/money in avoiding ones that were little help.

You can use the web site / forum Search - choose Advanced - to find posts only by him. Look for 700HP as one of the other ideas

 

Thanks for your reply. I have been in contact with this true pioneer and got lot of very important information. He has truly done a huge job in designing the kit and testing different parts.

Apparently there are not too many other people who have tuned their Jags that much..

Hopefully someone could still answer tho my key questions.

-Tama