Just ordered the Mina Pulley kit for my 2008 XKR 4.2. Anyone have any experiences with this Mod?

 

You would better have asked the question before ordering the kit.

Well since you already ordered it, just share your experience with us!

 

I DID A FAIR AMOUNT OF RESEARCH, AND HAVE BEEN GOING BACK AND FORTH WITH A JAG MECHANIC. However, do you feel there is something I should have known? Please share.

 

You probably used the "Search" feature, but if not three threads came up on the XFR forum when searching under "Mina Pulley". Here's the link to them...
Jaguar Forums - Jaguar Enthusiasts Forum - Search Results

 

I take it the caps you used on your reply indicated irritation. I'm trying to edify, not irritate. When I first looked into itfor my 2005 XKR, I was told that the pulley itself, to run the supercharger 6 or 8% faster (I don't recall which) would also run the engine hotter and for safety to the engine, would require a larger intercooler between the two stages of the siemens supercharger. Also a larger air inlet filter would be needed, and yes, it would be nice if we are going to do more gulping on the front end (intake cycle) to do more breathing on the back end (Exhaust cycle) and therefor, it would be proper to get a higher performance exhaust system. Then, with those changes, I would need a reprogram of the ECU. That was $5,700 and got me 78 HP gain. Remember , the stock 4.2 liter is developing a heat load of about 100 HP more than the 400 it was originally made with and the extra HP is used to drive the supercharger. So when you talked to the mechanic, did he tell you all that? The 75 promised HP gain became 68 for whatever reason, also if I had asked for the porting and polishing of the heads, I would have got more HP-35 to be exact, but at a cost of $3,500, or $100 per horsepower. At the time I declined on the porting. And looking back, yes, could have been a bit faster but the Perillis are nail magnets and only giving me 11,000 miles or so now, sow who needs the extra 35 HP after you already have nearly 500?

 

I think it would be helpful to talk directly (phone) with Mina.
From what I have been able to gather, the Mina pulley is not a radical boost increase. No doubt it will reduce gas mileage, but how much is very dependent upon your right foot.
Any increase in boost increases air intake temperature, which increase can cause the start of detonation, which the motor ecu compensates by dialing back ignition advance, which decreases power. So, a larger intercooler radiator will help, not only with the Mina pulley, but also the stock motor. Even then, you are limited by size of the intercooler itself which lies beneath the supercharger.
My guess is that the stock ecu can easily compensate, without reprogramming, the Mina pulley. Bear in mind that the ecu will maintain 14.7:1 fuel ratio in closed loop with just about any off-the shelf mod - it is that flexible. When you step on it, the ecu reverts to open loop which dumps a huge fuel load to the motor. Most ecu's on open loop are pig rich, and intake/exhaust mods do not per se cause the motor to run over lean.
I think anyone who is modifying their XKR should invest in an air/fuel ratio meter to monitor the effect of their mods.
The Jag's intake tract is a true cold air intake system, but suffers from small filter size. Mina makes a new filter system for about $225, a reasonable price.
I think the Jag OEM cat back system is fairly well designed. It may not be loud enough for some people, but it does deliver. The "active" exhaust with muffler valve is an effective remedy for exhaust drone.
I am surprised that no one effectively markets long-tube headers for the Jag. This may be an engineering challenge. But, my experience with long-tubes on GM autos is a hp increase of about 2X that of the typical cat back system.
I would steer away from "porting and polishing, etc" claims. This is a delicate art; and I have yet to see any objective published results.

 

Sorry, did not want to imply irritation with the caps. It was just a typing error. I do appreciate all the feed back though. I'm more concerned about the installation more than anything else. The recommendation from Mina and the general concenses is to cut the original pulley off. Which means there is no going back. The alternative of pulling the old pulley is labor intensive (expensive). You have to shell out $170 some for the correct puller from Eaton, or you will end up damaging the old pulley. This is along with the extra labor of removing the fan assembly etc. To get the puller tool to fit. Only looking for a 25 Hp gain. Mina tells me the computer can adjust itself for this level of boost increase. The Mina pulley is on the low end for boost increase psi compared to other pulleys available after market. Hopefully low enough for the intercooler the handle.

 

Thanks for taking the time to discuss- this makes perfect sense.

 

The advantages of running a smaller pulley are better mid-range torque andbetter throttle response. The Mina pulley is not radical enough to require a modified intake or exhaust and, unless you run the engine at redline, is not going to cause enough additonal heat to noticeably pull timing.

Cutting the old pulley off is the only way to go unluess you invest in the correct puller. Don't worry about cutting the original pulley off, you won't needit to go back on. I saved my original but it's a just paper weight now.

When you install the new pulley do a hard reset (disconnect the negative battery terminal and touch it to the positive for 10 seconds). This will allow the ECM to adapt to the additional boost more quickly.

I would recommend high efficiency cats as your next mod but I modified my car in the reverse order. Let us know how you like your new pulley

 

This is what I was hoping. 13psi to14.5 didn't seem radical enough to cause heat issues. Appointment is made for install. I'm going to let them cut the old one off. Unfortunately, I'm going to miss the last day of the local dragsptrip for the season. I wanted to see if repeat full throttle passes would diminish in performance do to extra heat. I know this did not happen stock. The air is cooler now anyway, and there is always next year.

 

So what is the result of your upgraded pully? are you happy with the upgrade?

 

Finally got the Mina pulley on. The throttle response does seem a little more snappy. Just drove it home today, so I'll need a little more time for the computer to relearn the new boost. Like I said, can't get to the dragway do to seasonal closing. This is where I'm hoping to notice a difference in the spring. I'll note any changes I feel in performance in a little more time with street driving. Note, when cutting off the stock pulley, A Snap ON power steering puller tool is needed to install the new pulley. Having to order this tool is what took a little longer with the install.

 

I'm interested in your sense of how noticeable the difference is, and whether you had any bad experiences at all (even small ones) with this mod.

Thanks,
JustNiz

 

I feel that the car definitely pulls harder when accelerating in drive mode. Especially in 2nd and 3rd. It has improved the throttle response. It seems the car just wants to go, even when just pulling away from a traffic light in drive mode. I have driven it quite a bit now, and checked the belt after each good trip. There are no signs of belt wear, or any smell of burnt rubber. Also, no warning lights have come on so far. In conclusion, I'm satisfied with the upgrade. Can't say for sure that it added 25 Hp to the wheels, but I feel a difference. The car feels a little more exciting now, even when not in sport. Can't wait to see if it improves 1/4 mile times.

 

Just to update on the pulley upgrade. I had the car at the drag strip yesterday for 4 passes. My best mile per hour before the upgrade used to be between 107 and 108 in the 1/4 mile. With the upgrade it was consistently 110 mph for all 4 passes. Mph usually reflects horse power regardless of pass time. This leads me to believe there was an increase in HP. I also had my best pass time. I can't say for sure that this doesn't account for differences in weather, humidity, etc. I just wanted to note the difference for anyone interested in the upgrade. One finale note, I did the passes consecutively and the results where more consistent than before the upgrade. This tells me the intercooler is handling the new pulley just fine.

 

Well this is great news... I got a mina pulley for my 09 xkr but have not installed it yet.