Owned the XFR for about 2 years and been wanting to upgrade the power for a while. I have the X pipe already with the center muffler and resonators removed, mated to two Varex mufflers. I was initially thinking of just doing the upper pulley and tune from VAP, but after seeing others run dual pulleys on the V8 and get near 590 WHP and 580+ WTQ, I am interested in going the dual pulley and tune route.

My only concern, I have only seen XFR-S and F-Type owners run the dual pulley setup. Those cars have the ZF8HP and mine is the ZF6HP transmission, would my drivetrain be able to handle that amount of HP and TQ? My car is currently right under 60k miles, I plan on doing the transmission and diff fluid flush. Anything I should address to handle that power for the hot climate we have in Atlanta?

 

I thin I saw somewhere that with upper and lower pulleys done you get the supercharger at over 18,000 rpm and beyond its efficiency limit. The Eaton TVS are rated to 18,000 max

 

If you haven’t done the upper pulley yet, I wouldn’t bother with it, for two reasons:
1) It’s nonreversible, meaning you can’t undo the installation of the smaller supercharger pulley
2) Both pulleys push the supercharger to its limit and in warmer climates you will only be pushing hot air, and not making any more power.

I recently recommended another local to me XFRS owner to do the lower pulley only with a tune, and when we ran each other it was hardly a difference between us.

As for the limits of the six speed I wouldn’t be too worried about it Jaguar pushes XRS-GT pretty hard with that 6 speed

 

I think that there are multiple torque limiters in place that won't let the car go over 700Nm so I wouldn't worry too much.

I was advised to not put both pulleys on due to the reasons that others have mentioned so have just the top pulley, tune and cross pipe on my '10 XKR and it is putting out around 630bhp based on standing quarter terminal speed times so you may get slightly more with the bottom pulley and a decent tune.

 

I did the eurotoys lower pulley and tune and love it. for many the same reasons many on the forum recommended it as a better performance option as well as a quick return to stock. I just put a mina axle back I got off ebay for $500 along with the center section delete and x pipe she sounds nice. I also have a mina intake and filters so im pretty much done now. Next spring ill get some wider rims and tires and spend some time at the track and dyno it. winter is here

 

I read through all your threads on the XFRS upgrades and track runs and that's what really had me interested in getting both the pulleys. I know the 3.0 engines come with the smaller pulley from factory so most of the threads I saw, mentioned those engines should only update the lower crank pulley. Given the 5.0s come with 66mm size pulley, swapping that with the 1.5lb pulley and changing the crank pulley to a larger size should make the supercharger spin at similar RPM to the tuned/pulley'd 3.0 motors.

But looking at specs from the Eaton's website for the TVS R1900 (https://www.eaton.com/us/en-us/catal...fications.html) on the V8 and TVS1320 (https://www.eaton.com/us/en-us/catal...fications.html) on the V6, the max rotor speed on the V6 supercharger is 20,000 vs 18,000 on the V8 supercharger. So, the dual pulleys on the V8, like everyone stated, is not optimal.

Thanks for all the feedback on this topic, lower pulley and tune seem like the best bet.

 

As you get closer reach out to Mike at eurotoys my experience with him was great. Do to our relative location I drove down and spent the morning with him while he did my car. Good guy and always responds quickly to questions.

 

I have heard good things about Eurotoys, but I am leaning towards VAP for the tune and lower pulley combo.

 

When reading through other forums on the lower pulley replacement, another forum member mentioned this:

"When replacing the lower pulley, only one sided belts come in the right size, so a smooth idler pulley needs to be installed to accommodate. Adds to the materials cost (minor), but the total labor effort (and cost) is much less than swapping out the upper pulley." But this was on the V6.

Does this apply to the V8 as well? Did you get everything you needed from the the lower pulley kit to do the replacement or did you have to buy additional material?

 

I purchased the stage two kit and it came with everything I needed. I drove down and Mike installed everything for $250. It came with a gates belt.

 

Just a note about changing your idler pulley to match the belt?
If you go with VAP like I did you won't need to change the idler pulley as Stuart now has had the correct SC belt made.
So that means a lower pulley swap is beyond simple and quick. 6 Bolts and change the belt. Your done!

Hell I only took off the intake "Y" pipe for great access!




I changed it out on my 2014 XJR in under 2 hours and I am very slow. Also do the pulley from the top of the engine. I read of other installs going from underneath and that's way harder!
I have lift too so I looked at both methods of attack before I got into it.

One other thing is depending on the year of your car the 5.0L SC came with either a silver or black pulley. Not sure about the difference but they did ask.





It's bigger and fits great! Still only seeing around 10.5-11 psi max and am working on why it's not more?
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Where are you pulling boost from? Using a boost gauge or OBD II reader? OBD are notoriously slow and not totally reliable to read in the proper increments. If you have a gauge it will read better.

 

They need to know the colour of the OEM crank pulley because the larger pulley upgrade is different depending on which one you have
Same operational diameter but a different internal shape and offset and different belt length.
Same with the V6 on the F-Type, I got the wrong ones first of all and they didn't fit right.

 

To answer this question, both Velocity AP and Eurotoys offer the double sided longer/ correct belt as an option now. Initially for both Velocity and Eurotoys you had to change your idler pulley, for the single sided belt, but now I believe both vendors supply a double sided belt that works for the larger crank pulley, and this also means you will not have to change your idler pulley. But having had to replace the idler pulley back to the stock one, after switching form single sided to double sided, that was literally a 15minute job, least of your worries.

Either way you will get everything as part of a package, you just have to contact the vendor of choice, and they will fill you in on all the details.


I to noticed my boost maybe maxes out at 12.5 - 13.0psi, I use an OBDII reader with an app on my iPhone, and I was told by Velocity that where OBDII is sensing the pressure isn't the correct location... I haven't bothered installing a boost gauge, as I don't want anything to clutter the interior, and it's not like I'm worried about performance, at the moment. If I wasn't getting the results on the dyno, and the 1/4 mile strip, then I might start looking at getting more meaningful boost readings, but no need for trouble shooting at the moment. Nothing would make me happier than making the power that I do with lower boost (safer way to do it, but definitely isn't plausible).

 

That's a good point and I don't know where it's reading the boost from.
Is there any way to tell? Where should we be getting it from?

There is a ton of PID's but I can only see one "Boost Pressure" in any of these scanners
With these apps your kind of stuck because you can't get behind the scenes to see what's really happening.
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Yes that's why I asked about the boost gauge, OBDII uses MAP (manifold pressure). For full boost pressure you need to be before the manifold ( that shows any limitations on the boost through the system ie leaks)

Here's the 1320 boost map: The Pressure ratio is the pressure in Bar over Atmosphere (14.7) so at peak efficiency say 1.73 (=14.7*1.73)-14.7=11.4
At 1.9 efficiency starts trailing off, 13.23. Tough to squeeze any more out of this one at least

As effcicney goes down any increase in boost does not equal a simialr increase in flow ( and flow is what you want, PSI is no that important)

 

having only done an upper pulley, I'm often wondering about the lower one. my tune has 7,000 rpm shift with soft and hard cutoffs at 7200 and 7400 rpm.
i'd entertain the lower in conjunction with my upper for all the part throttle stabs and the added torque lower in the power band. redline engine speeds are only occasional and i suppose you could over boost there. this may just mean time to shoft a little sooner / safer anyway amd wouldn't you get benefits all the way up through the power band?
one thing i marvel at in these cars is the part throttle hill climb abilities at lower RPMs in 4th or 5th gear. when i can easily fly up a fill in a gear that has another 100mph of potential in it (above current speed), i smile wide