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5.0 sc modifications. Anyone do upper and lower pulleys?
I’ve done the upper pulley and was wondering if it’s beneficial to change the lower crank pulley?
would it heat soak?
what’s needed to run this setup
thanks guys
Always do a tune and lower pulley first. That gets you the most for the least amount of money. The upper pulley is less effective plus WAY more difficult to install. Remember the upper pulley needs to get smaller in diameter to make more boost. This leads to less belt wrap and belt slippage. VAP and others offer GripTec pullies and if I ever do go with an upper pulley I would make sure to use that surface treatment.
The lower pulley is much better because you will be increasing the diameter and that gives you more belt wrap and less slippage. The limit to the lower pulley is how large of a diameter will fit the engine. Plus it's about a 30 minute job to remove the stock lower pulley and install the after market one. It's REALLY easy!
If you plan to run both pullies I would get a bigger IC before doing those mods. Several are out there and don't forget to upgrade the IC pump as well. I also recommend using VAP for the tune but it's your choice. Again after dropping the front bumper cover all the IC stuff is in plain sight and much easier to work on. The IC sits in front of the cooling stack so nothing else needs to be removed.
If your interested in pushing the 5.0L engine start reading the F-Type forum as we have some real racers over there! On the XJ forums not so much. Meth injection and killer chillers, transmission tunes, pedal controllers. Best of all is that larger 2300 TVS blower from Harrop!
BUT bring your checkbook!
I am making around 620 HP at the crank. On a Dyno my car made 530 HP/540 TQ at the rear wheels. I think it makes more (Don't we all!) because the dnyo guy had never done a Jag and I only got 5 pulls. Each pull gave high HP numbers as he figured out how to run the car on the dyno. Biggest problem was it kept kicking down gears when he did not want it to. So he thought it had more in it and I do to but I ran out of time. I was only suppose to get 3 pulls but since he was having trouble he gave me a few more. This is with a lower pulley and VAP tune. Larger IC and bigger IC pump. Pretty basic mods and fairly simple to install for a home DIY guy like me.
I have sent data logs to VAP as they will custom tune your car as well as selling canned tunes. This is an additional cost. I must say the canned tune is very nice and the car is a real pleasure to drive! Especially after removing that ridiculous Symposer stuff!
But I am lusting after that 2300 blower with meth injection!
Heat soak just depends. I will tell you I live in the hot south and can't say I have ever got the car to heat soak. Now my old 2005 S-Type R would heat soak even when stock. But that shows how much better these newer TVS blowers are compared to that old "Heaton" M112 in the S-Type.
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I have owned numerous cars and been on many different forums.
I must say you sir are by far the best I’ve ever encountered.
you’re a blessing to this community and I really appreciate your input.
thank you
Originally Posted by clubairth1
Always do a tune and lower pulley first. That gets you the most for the least amount of money. The upper pulley is less effective plus WAY more difficult to install. Remember the upper pulley needs to get smaller in diameter to make more boost. This leads to less belt wrap and belt slippage. VAP and others offer GripTec pullies and if I ever do go with an upper pulley I would make sure to use that surface treatment.
The lower pulley is much better because you will be increasing the diameter and that gives you more belt wrap and less slippage. The limit to the lower pulley is how large of a diameter will fit the engine. Plus it's about a 30 minute job to remove the stock lower pulley and install the after market one. It's REALLY easy!
If you plan to run both pullies I would get a bigger IC before doing those mods. Several are out there and don't forget to upgrade the IC pump as well. I also recommend using VAP for the tune but it's your choice. Again after dropping the front bumper cover all the IC stuff is in plain sight and much easier to work on. The IC sits in front of the cooling stack so nothing else needs to be removed.
If your interested in pushing the 5.0L engine start reading the F-Type forum as we have some real racers over there! On the XJ forums not so much. Meth injection and killer chillers, transmission tunes, pedal controllers. Best of all is that larger 2300 TVS blower from Harrop!
BUT bring your checkbook!
I am making around 620 HP at the crank. On a Dyno my car made 530 HP/540 TQ at the rear wheels. I think it makes more (Don't we all!) because the dnyo guy had never done a Jag and I only got 5 pulls. Each pull gave high HP numbers as he figured out how to run the car on the dyno. Biggest problem was it kept kicking down gears when he did not want it to. So he thought it had more in it and I do to but I ran out of time. I was only suppose to get 3 pulls but since he was having trouble he gave me a few more. This is with a lower pulley and VAP tune. Larger IC and bigger IC pump. Pretty basic mods and fairly simple to install for a home DIY guy like me.
I have sent data logs to VAP as they will custom tune your car as well as selling canned tunes. This is an additional cost. I must say the canned tune is very nice and the car is a real pleasure to drive! Especially after removing that ridiculous Symposer stuff!
But I am lusting after that 2300 blower with meth injection!
Heat soak just depends. I will tell you I live in the hot south and can't say I have ever got the car to heat soak. Now my old 2005 S-Type R would heat soak even when stock. But that shows how much better these newer TVS blowers are compared to that old "Heaton" M112 in the S-Type.
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Well thank you VERY much! Usually these types of compliments are reserved for our senior member Karl!
I am biased because when I saw that red car it's almost a twin to mine.
Is yours is IRR too?
Picture from dealer when I got it back in 2017.
The dealer has stopped selling any Jaguars and is only a LR dealer now.
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Last edited by clubairth1; Apr 15, 2026 at 09:49 AM.
Well thank you VERY much! Usually these types of compliments are reserved for our senior member Karl!
I am biased because when I saw that red car it's almost a twin to mine.
Is yours is IRR too?
Picture from dealer when I got it back in 2017.
The dealer has stopped selling any Jaguars and is only a LR dealer now.
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Same with my local dealer here in the DFW area. Only LR going forward. Which kind of sucks. But there aren't many Jags to sell these days either.
I’m assuming you’re asking me about the paint?
if so then mine is Radiance Red Pearl
Your XJR is beautiful, I would buy one if I ever see one for sale that’s in good condition.
I just picked up the one on the right and it only has 35k on it. It’s pristine so it’ll stay stock
I have a silver and black one that I’ve been modding.
the red one is actually for winter
Originally Posted by clubairth1
Well thank you VERY much! Usually these types of compliments are reserved for our senior member Karl!
I am biased because when I saw that red car it's almost a twin to mine.
Is yours is IRR too?
Picture from dealer when I got it back in 2017.
The dealer has stopped selling any Jaguars and is only a LR dealer now.
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Agree with Clubairth1.
I am about to exchange the lower pulley to 181mm and upper pulley 60mm, sc cooler pump to bosch, and heat exchanger to Moshimito triple core, and fuel pump. I have already had the supercharger ceramic coated for heat isolation, done a basic flat filter to cone conversion (more for the sound ), as well as a thermostate and all cooling upgraded to aluminum, and injectors. Dyno is booked for 4 weeks from now. I may back the upper pulley to 62mm but wanted to see how an aggressive bottom hit feels. However I am aware at top end the supercharger will hit its red line 250 engine from early. Obviously I am not tracking a XJL so max high end revs isnt an issue. Going to be a fun month!
Always do a tune and lower pulley first. That gets you the most for the least amount of money. The upper pulley is less effective plus WAY more difficult to install. Remember the upper pulley needs to get smaller in diameter to make more boost. This leads to less belt wrap and belt slippage. VAP and others offer GripTec pullies and if I ever do go with an upper pulley I would make sure to use that surface treatment.
The lower pulley is much better because you will be increasing the diameter and that gives you more belt wrap and less slippage. The limit to the lower pulley is how large of a diameter will fit the engine. Plus it's about a 30 minute job to remove the stock lower pulley and install the after market one. It's REALLY easy!
If you plan to run both pullies I would get a bigger IC before doing those mods. Several are out there and don't forget to upgrade the IC pump as well. I also recommend using VAP for the tune but it's your choice. Again after dropping the front bumper cover all the IC stuff is in plain sight and much easier to work on. The IC sits in front of the cooling stack so nothing else needs to be removed.
If your interested in pushing the 5.0L engine start reading the F-Type forum as we have some real racers over there! On the XJ forums not so much. Meth injection and killer chillers, transmission tunes, pedal controllers. Best of all is that larger 2300 TVS blower from Harrop!
BUT bring your checkbook!
I am making around 620 HP at the crank. On a Dyno my car made 530 HP/540 TQ at the rear wheels. I think it makes more (Don't we all!) because the dnyo guy had never done a Jag and I only got 5 pulls. Each pull gave high HP numbers as he figured out how to run the car on the dyno. Biggest problem was it kept kicking down gears when he did not want it to. So he thought it had more in it and I do to but I ran out of time. I was only suppose to get 3 pulls but since he was having trouble he gave me a few more. This is with a lower pulley and VAP tune. Larger IC and bigger IC pump. Pretty basic mods and fairly simple to install for a home DIY guy like me.
I have sent data logs to VAP as they will custom tune your car as well as selling canned tunes. This is an additional cost. I must say the canned tune is very nice and the car is a real pleasure to drive! Especially after removing that ridiculous Symposer stuff!
But I am lusting after that 2300 blower with meth injection!
Heat soak just depends. I will tell you I live in the hot south and can't say I have ever got the car to heat soak. Now my old 2005 S-Type R would heat soak even when stock. But that shows how much better these newer TVS blowers are compared to that old "Heaton" M112 in the S-Type.
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Can you share the whats and wheres you got for the pulley and IC components please sir? If the IC and pump aren't that big of a deal I can cetainly take those on.
As to lower vs upper pulley... What I have seen was the lowers run several times what the uppers do. Have I missed a vendor that was a bit more reasonable with them? TIA
I use VAP. I wait until the end of the year for their sales. But I don't know why the difference in price. There are other vendors for pulleys too.
Here is my thread on bigger IC and bigger IC pump. With the bumper cover off it's pretty easy. Upgraded IC and Pump
Do read that thread because I got burned and paid about $400 more for the exact same IC. I just did not know who made what! Now again time has gone buy and there are other IC options and pumps now. If your real serious there is the "Killer Chiller" setup several have added to their car. And good ol Meth injection as well.
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5.0 sc modifications. Anyone do upper and lower pulleys?
), as well as a thermostate and all cooling upgraded to aluminum, and injectors. Dyno is booked for 4 weeks from now. I may back the upper pulley to 62mm but wanted to see how an aggressive bottom hit feels. However I am aware at top end the supercharger will hit its red line 250 engine from early. Obviously I am not tracking a XJL so max high end revs isnt an issue. Going to be a fun month!
