Hey guys,
I just ordered the Mina exhaust and supercharger pulley for my 2011 XJL Supercharged so I was pretty excited until I talked to my friend who told me to be careful because people's cars were overheating after they installed aftermarket pulleys. (Not specifically Mina) Does anybody have any experiences with Mina pulleys or any aftermarket pulleys they could share? Thanks

Patrick

 

I think what he means is the car will go into heat soak quicker.

Your car does not overheat but the intake air gets so hot the engine computer starts to pull boost and timing to prevent pre-ignition which if not stopped or prevented will destroy your engine by knocking holes in the pistons.

If you upgrade the pulley the car will see more boost and increase the intake air temperature.

Since everything is automatic these days what will happen is the car once it enters heat soak will have very little power because of the computer limiting boost and timing. Generally not a problem as far as damaging the car but you put the pulley on to get more performance not less!

The factory has a pretty good compromise so you really don't want to increase boost very much but as all factory settings it has a safety factor so there is more power to be had!

What should be done is to cool the intake charge while also adding more boost.

Have you heard of the Killer Chiller or spraying Meth?
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I've been looking into ETG (ECU Tuning Group) out of Freemont California. They offer an ECU tune that gives about 50 to 60 HP and a ECU/pulley that takes the SC V8 to 618 HP. but they specifically state that just a pulley can throw off the timing ( Pulley Kits | ECU Tuning Group ). Before I do the tune I am replacing my worn Dunlap's with Michelin Pilot Super Sports at the XJR sizes 265/35/20 and 295/30/20 for more traction. Personally I would do some more investigation before just putting on a pulley. Check out ETG here is a link to their old site that has more information ( ECU Tuning Group ). BTW they are one of the largest suppliers to Hennessey in Texas and do tons of Range Rovers.

 

With the 5.0L cars putting on a pulley without getting a tune is a waste of time & will probably lose you power/driveability. The majority of the power output is in the tune.

The consensus now is that the ECU restricts the opening of the throttle; you simply do not get Wide Open Throttle. By limiting the throttle opening, the engines output is limited to set power (torque) values.

This is also seen as limiting boost, with the different V8 tunes showing different peak boost numbers.

What is actually used as the measurement value to determine when the ECU throttles the engine back is not 100% clear, but I suspect it's the mass airflow. (so if you put a pulley on the supercharger, you will get more airflow, the ECU will throttle back)

The "tunes" are in fact removing the limit values, or at least raising them, so that the throttle opens more.

This effect has been seen now on the earlier 4.2L engines running Denso ECU's, as well as the 5.0L running Denso ECU's and the current engines running the Bosch ECU's.

This is how one engine can have so many different power outputs;

470hp (XF & XJ Supercharged)
495hp (F-Type V8S)
510hp (various models)
550hp (various R models)
575hp (Project 7)

Absolutely same engine, just throttled back to limit power output.

The tune is the key to power, the pulley is the icing on the cake.