Happy Lunar New Year to everyone.  Hoped you had a good one!

It has been a relaxing one for me and having nothing much to do, I decided to install something new to my car.

Nothing fancy, nothing too technical, just some simple 12 year old technical class tasks.

The car this time is the 2001 Mazda MX-5.  This car has a room light so dim, its basically useless.  When its dark, you can forget about tearing coupons, looking for Touch’n'Go Cards if you dropped it, or something essential like reading your map when lost.  Sure, we all know the MX-5 is not the most practical vehicle to own, but come on, Mazda could have put in a couple more lights couldn’t they?!?

Anyway, since we have a full warehouse of car accessories, I basically have access to numerous types of super bright LEDs at my disposal.  This was something that I have been wanting to do since early 2009, but well, procrastination is always good…

so that I can work on other MORE important stuff.

I chose these

Small and bright enough to fit on one of the panels on the dashboard.

Of course, just a good dose of double sided tape will work well enough to have them fully functional and connected to a on-off switch.  But if that were my standards, I’d rather die or just put something like this instead, something we use in the house.

NO!  I will not have any of those slipshod work… I just got to have them the best, the neatest and something that will make me smile every time I use it.

While surfing Yahoo!Japan, I came across this used switch.  Originally used to disable power to the windows, but it will work for my application too!

Now, time to get the hands dirty and start working.

Firstly, we drill a small hole.

Then get a hole saw the right size and drill it to suit.  Since it is the Lunar New Year, and none of the hardware shops are open.  I just have to use the closest sized hole saw I have.  It would have saved some time if I got the right sized one as I can just drill it through and have it fit perfectly than having to port the hole to get the perfect size.

After we are done with that, time to port it so that it matches perfectly and the LED will sit flushed with the surface.

Trusty Standard Abrasive Head Porting tools to the rescue.

Perfect fitment!

With all that hard work out of the way, time to wire up the car.  Since these LEDs sap very little power, I just thought that its easier to wire the 12V power direct so that I can have it working as and when, rather then having to switch the ignition to Acc.

Some simple wiring work, and everything was hooked up nicely.

Factory style switch.

Super bright footwell!

A shot at night, man, I need shades!

Now, this was how the MX-5 should have come right from the factory.

Wiseco recently released a shelf piston in 12.4:1 Compression Ratio for the K20A motors.  This was previously sorely lacking in their 2008 and 2009 catalogs.  A high compression piston for K20A motor was almost solely dominated by CP Pistons as they were very early adopters in this category.

I have always been a fan of Wiseco Pistons as I find them to be consistently superior in quality and value.  Most of their offerings come in lightweight guises and also has the skirt coated.  Many other companies tend to charge extra for that.

What we have here are all shelf pistons from the various companies.  They are in the same bore size (86mm) and for stock K20A motors.

Left: CP Piston X-forging.  Weighs 295 gram.  Advertised 12.5:1 Compression Ratio.  Skirt uncoated.

Middle: Wiseco Piston.  Weighs 320 gram.  Advertised 12.4:1 Compression Ratio.  Skirt coated.

Right: Stock PRC Piston.  Weighs 336 gram.  Factory 11.5:1 Compression Ratio.  Skirt coated.

All opinions are just based on visual inspection on these.

Firstly, lets take a look the obvious difference in the pistons.

• Wiseco looks to have the highest dome.

Although these have the highest dome, but only an advertised compression ratio of only 12.4:1.  It could be that the dome volume is being negated by bigger valve pockets and thus sacrificing a little compression ratio.

• Wiseco and stock pistons has the skirt coated.

This would aid in reducing friction and making for a more efficient engine.  This can even lead to improved fuel economy.

• Wiseco pistons offers anti-detonation grooves on top ring lands.

The stock piston also has the same anti-detonation grooves, but they are very shallow and finely cut and does not show up very well in the pictures.  CP pistons however do not have any of the anti-detonation grooves present in their design.

• CP pistons weighs the least.

The mass on the CP piston is very evident.  Just by holding different pistons in both hands, you can already tell that the CP piston is the lightest of the lot.

• Wiseco has the deepest valve reliefs.

Upon measuring with my trusty vernier caliper, I can safely deduce that the Wiseco piston will accept higher lift camshafts with significantly less problems compared to the stock piston.  In comparison to the CP piston, it is marginally deeper, but at this stage where we are getting aftermarket camshafts bordering 14 mm of lift, every little bit of additional clearance adds up.

• CP piston has 2 sharp edges along top ring land

Both the CP and Wiseco piston are machined to accept the largest possible intake valve, and as such part of the top ring land is being machined into.  Running my fingers along the edge, I realize that the machining process CP piston did for their edges does not have “finishing” work done to deburr it.  I would sand it down a little bit more if I were to put it into any engines.

• CP piston under piston area more weight savings

There are more hollows in the forging that the CP piston uses; thus saving weight.  It looks like CP piston used a special custom forging for this piston in order to achieve its superior weight.

• Wiseco has thicker top ring lands

The Wiseco piston measures a thicker ring land of 7.4mm vs the CP piston’s 5.2 mm.  This thicker ring land should give little more insurance in abusive racing environments.  The stock piston ring land measures 6.5 mm.

PS: In all pictures, Left-most piston is CP, Center is Wiseco and the Right-most is Stock PRC.

Now, lets compare between wrist pins, Left is CP and Right is Wiseco.

Both of the wrist pins weigh the same; 72 grams.  The stock one is 90 grams.  I do however realize that the Wiseco wrist pin has a taper on both outsides in its bid to keep the weight to the minimum.

Hope the data discussed here is of some use to anyone who are wanting to choose between these pistons.