bigx5murf

Why would the mazdaspeed engine have a cooling advantage?

Track

Interesting you ask...
https://www.miataforumz.com/nb-1998-2005-7/thoughts-either-option-273/

follow the links in that thread!

bigx5murf

I've only skimmed the 3 threads mentioned there. It would seem the mazdaspeed head's coolant flow is the same as all 01-05 NBs?

Track

well, its odd. its got the porting of 99 head, with the port shapes of the 01+, and it has a few ports that the 99 head doesn't have. So it seems to me that its the culmination of mazda's research on the BP heat issues in the longitude configuration.

I can't really explain it well, I suggest you read the 4 page thread thoroughly. it is covered on page 3 and page 4.

atlnb

i'm curious how much hp you can produce with a 01 bottom end, 99 head, 0.020 shave, EUDM/JDM intake manifold, bp5a cam and a reflashed ecu.

Track

well, you won't be able to reflash the ECU (you will need an alternative to the stock ecu though). Emillio pretty much did this:
http://forum.miata.net/vb/showthread.php?t=372717

159whp.

atlnb

that's kinda what i was thinking

Johnny2Bad

Assuming it's true that a N/A Miata can beat a similar but somewhat superior power rated turbo car, I would attribute it to having more "power under the curve".

The "curve" is the torque curve of the engine. The broader and flatter the curve, the faster the car will be, all other things being equal (drivetrain, etc). Thus you would need more power in a car that primarily made power at a higher, narrower RPM range to be equivalent, i.e. same Elapsed Time, in a pure acceleration test.

Given a road course, the outcome could be different.

bigx5murf

I don't believe that. Turbo lag is supposed to be a thing of the past nowadays with proper tuning. So I don't see NA having a significant torque curve advantage.

As for NA having an advantage on a road course. I think that's due more to finer control over the throttle especially mid corner. Turbo cars will boost even at part throttle, so throttle position control is kind numb.

Johnny2Bad

Not sure what turbo lag has to do with it; look at the torque curve of a turbo car and see what you have at 2,000 RPM. Any NA car that can make 170 RWHP will have plenty of torque there; a turbo car making "only" 200 RWHP is going to be at near stock torque levels there.

Regardless, the area under the curve isn't theory; it's what every serious engine builder pays close attention to.

As for the rest, reread the post; I suggested the turbo car wins the road course, where the strategy differs from a drag race.

The reason being you can choose gears in a road course and thus have control over the powerband you're using; with a drag race you don't choose gears; you run through them, so the torque values available at the RPM your next gear drops to becomes critical.

You should be dropping into the peak torque or just below Peak Torque RPM with each shift for lowest ET. With a broad curve you are in good shape there.

If Miata drivetrains were more robust you could launch at 4,500 RPM in the turbo car and be golden. But, I suspect most people wouldn't try that on their lightly modded, stock differential-equipped 200 RWHP turbo cars.

Although you'd have to take a few passes to figure out what's best for your car, I'd expect most drag race Miatas are doing second gear launches.