McLeod Clutch & Fidanza Flywheel Test

[Robert_McDonald]

5.0 Mustang Performance Clutch and Flywheel

There are times when true streetablity and the race track go hand in hand.

Text, Photos and Drawings,

By

Robert McDonald

I doubt you would be surprised to hear that about a third of tech enquiries are for vehicles that must serve as both street and drag strip capable machines. Many of those also have to be driven by two parties, one usually being the wife or girlfriend. When it comes to clutches a heavy duty clutch often means a heavy clutch pedal. Pushing a heavy clutch pedal in and out repeatedly in crowded traffic situations gets old real quick. So does listening to the rpm rise when the torque from your mildly modified 5.0 overcomes the clamping torque of the usually somewhat worn stock clutch. And the smell is not that good either!

So what to do. At this point you have to install a clutch so it may as well be something that holds way more than a stock clutch – but you do not want to have any higher pedal operating loads. If this sounds like you then GFN has a clutch recommendation that will suit you down to the ground. The clutch concerned is from McLeod Industries.

#1 High torque capacity and low pedal force are key claims for this McLeod clutch assembly (Pressure plate # 360048 and plate # 260830). We test just how well the clutch delivers in these areas.

The stock clutch was getting somewhat long in the tooth in one of our 5.0 project cars and exactly apposing this was the fact that bolt-on go faster parts were increasing the torque and hp. When traction was good as per the drag strip the transfer of engine output to the wheels was suffering to the point of mild clutch burning. It was obviously time for a new clutch so while that was being installed it made sense to install a lighter flywheel at the same time. For this a Fidanza steel faced aluminum flywheel was chosen. Also McLeod’s Red Roberts recommended their organic facing disc. Red claimed this would deliver better pedal modulation which is good for a more controlled drag strip start – especially if traction is at a premium.

Weights.

The McLeod pressure plate and disc tipped the scales at 21 lb compared to the stock items 22 lbs. This is a small but worth while step in the right direction. The flywheel though was where the biggest mass reduction was made. The stock flywheel was 20.5 lbs as apposed to the Fidanza flywheel at 11.5 lbs. The clutch assembly and flywheel then delivered a 10 lb saving of rotating mass. This may not sound much but it’s effect on the mass the engine has to rotate up to speed as well as accelerate forward is far greater than you may suppose. A ball park calculation (borne out as reasonably accurate by track testing) indicates that, for a stock Mustang with stock gear ratios, a 10 lb flywheel weight reduction is equal to a reduction of about 120 lbs in first gear and about 40 lbs in high gear. This may sound out of all proportion to what might be expected of a 10 lb drop in flywheel weight so let’s look into it in a little more detail.

When you stand on the gas and take your stock ratio geared 5.0 to the red line on the tach in first gear the car hits about 40 mph. The periphery of the flywheel mean while hits 230 mph! What we see here is that the flywheel has to be accelerated in two modes - both rotationally and forward. What we want is the engines energy accelerating the car forward not accelerating a mass in the system. The bottom line here is that the car will accelerate off the line quicker and ET faster with the lighter flywheel. In addition to that the shift will be faster as rpm will match quicker giving the synchro cones in the gearbox less to do.

Track Time.
After installing the clutch and flywheel assembly the first evidence of a change was that the engine responded to the gas pedal noticeably faster. As for the amount of effort to push out the pedal the clutch was everything McLeod claimed. Pedal effort was in fact down on stock by – at a guess about 10%. Engagement was silky smooth and overall the clutch and flywheel unit was all that you would want in terms of street use. After the requisite break in of some 500 miles we took the car to Rockingham.

#2 Here is how the flywheel face looked after about 40 drag race starts and just under 3000 miles. There was some evidence of burning but nothing to be concerned about.

A true back to back was not possible because of differing weather conditions and we had to look at times recorded before the stock clutch started to give out. Sure we can correct for weather but let’s face it; a correction is just that – a correction. Although the weather was favoring our ‘before’ runs done about 3 weeks earlier our 5.0 did record it’s best time and mph with the new clutch/flywheel combo.

#3 The pressure plate’s friction face was in very good condition with much less wear than would be expected.

A best ‘before’ of 13.713 was seen as apposed to a 13.651 for a reduction of 0.062 seconds. As for speed this only went up by a tenth of a mph. When the time honored drag strip weather corrections are applied the ET reduction rose to 0.077 seconds and the mph increase to two tenths of a mph. As for holding power the McLeod unit had it in spades. The test for this is to engage 4th gear, turn the engine up to about 5000 rpm and side step the clutch and mash the throttle at the same moment. When this was done the engine instantly stalled.

#4 The key to good pedal control on a traction limited start is the disc material. The McLeod 8000 series disc proved to be very good in this respect.

After about 6 months use the clutch and flywheel were pulled from the car (didn’t quite make 3000 miles). The wear is as seen in the accompanying photo’s. As can be seen no undue wear was present suggesting that at the power level our test vehicle was at (about 240 rear wheel hp) the clutch would have a more than reasonable life.

Based on what was seen during our tests it was hard to fault this clutch and flywheel assembly but, who knows, a longer test may have shown otherwise. That said the GFN rating awarded is a conservative 4.5 stars for an excellent product from both companies concerned.

Of the big mail order companies the best price for the pressure plate and clutch disc was from Jegs at $207 and $195 respectively. The flywheel from Jegs was $339.