Ok, who is making changes in ST4?

[CP]

All you do to spot a LWFW is pull back the rubber boot for the clutch fork and stick a pen magnet in there. If it doesn't get stuck to the flywheel then a lightweight aluminum unit has been installed. Easy to police provided you can find someone willing to crawl around underneath the cars.

[paultg]

....btw...I'm committed at this point.

If the BOD changes the swap rule..... I will be very VERY pissed.....and in SPC.

Just curious (not really a miata guy), how much more whp can you expect from the 1.8 versus the 1.6 once you include all the legal Street Touring mods like exhaust, chip, whatever?

The NA 1.8L's (94-97) were rated stock between 128 -133hp depending on the year, the early 1.6L's were 116 hp. The bigger difference is the hp and torque curves. I would assume the gains from ST4 rules would be similar with a 1.6 or 1.8, but I really don't know.

Troy, I've been doing alot of research on this, if you have any questions or want to trade notes let me know. I'm hoping to get my 1.8L on a stand and freshened up over the winter for an early season swap (march).

Paul G.

[CP]

For reference, my 99 with a 2 season old 1.8L crate motor with SM required restrictor plate dyno'd at 106HP in April. I'll be interested to see where it is next spring after the 45+ races it ran in 2010.

[paultg]

I know racing is different than street use, but my '91 with the 1.6L dyno'd at 95hp and 88 ft-lbs of torque with 116K miles. Pulls were in 4th gear (took forever) on a Dyno Jet 224 chassis dyno here in NH. Only mod was timing and a custom cat back with a high flow cat, according to some folks good for about 2 hp.

[Stynger]

....btw...I'm committed at this point.

If the BOD changes the swap rule..... I will be very VERY pissed.....and in SPC.

Troy, Ive done a bunch of these swaps. Give me a call if you have any questions.

[breakaway500]

"All you do to spot a LWFW is pull back the rubber boot for the clutch fork and stick a pen magnet in there."

Not quite good enough,Cy.

Flyin-Miata sells a lightweight STEEL replacement:

"These flywheels are 1.8 size. You can use them on a 1.6 car if you also install a 1.8 clutch.

We offer them in 13.5 lbs, often referred to as a "street" setup, and 10.3 lbs for a little more responsiveness. The heavier unit will be a little quieter on overrun (lightweight flywheels can cause the transmission to make noise on closed-throttle deceleration) and a bit easier to drive. The stock flywheel is around 21 lbs. The heavier weight is also well suited to supercharged cars to avoid idle droop, while the lighter model is for those who are looking for the sportiest experience.

This particular flywheel is made of steel with an integral ring gear. Unlike aluminum flywheels, it will use your factory pressure plate bolts."

For many mods,the honor sytem will be the only way to police them.