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Cactus
Cactus Reader
6/14/17 11:31 a.m.

With a proper tune, 100% (OK, 99.whatever%) methanol will give you the most power out of any readily available fuel without mechanical modifications.

Not really in the same cost bracket as e85 though.

alfadriver
alfadriver MegaDork
6/14/17 12:34 p.m.

In reply to Cactus:

While true, in CSP trim, that's not allowed- M100 is not a legal pump fuel.

Hungary Bill
Hungary Bill GRM+ Memberand UberDork
6/14/17 1:05 p.m.
Cactus wrote: With a proper tune...

I've waited for an in long enough, I'll take it!

White Lightnin!

Keith Tanner
Keith Tanner GRM+ Memberand MegaDork
6/14/17 3:39 p.m.
iceracer wrote: I found, on my ZX2SR, that an underdrive pulley to be a better power producer than many of the usual stuff. Not even mentioned any more.

On a Miata with any sort of horsepower, that means oil pump death in fairly short order because the crank pulley is also a damper - this is fairly typical. Better way to save rotating mass is on the flywheel, if you want to slow down your accessories then put larger pulleys on them.

rslifkin
rslifkin Dork
6/14/17 3:45 p.m.
Keith Tanner wrote:
iceracer wrote: I found, on my ZX2SR, that an underdrive pulley to be a better power producer than many of the usual stuff. Not even mentioned any more.
On a Miata with any sort of horsepower, that means oil pump death in fairly short order because the crank pulley is also a damper - this is fairly typical. Better way to save rotating mass is on the flywheel, if you want to slow down your accessories then put larger pulleys on them.

Do they not make a damper with a smaller pulley or one that takes a bolt-on pulley to allow a smaller one to be used?

Keith Tanner
Keith Tanner GRM+ Memberand MegaDork
6/14/17 3:53 p.m.

There's more demand for dampers that are more effective than stock, and there's a minimum size for that sort of thing. Oil pump failure sucks a lot more than spinning your water pump at the speed Mazda intended

Knurled
Knurled GRM+ Memberand MegaDork
6/14/17 4:56 p.m.
Keith Tanner wrote:
iceracer wrote: I found, on my ZX2SR, that an underdrive pulley to be a better power producer than many of the usual stuff. Not even mentioned any more.
On a Miata with any sort of horsepower, that means oil pump death in fairly short order because the crank pulley is also a damper - this is fairly typical. Better way to save rotating mass is on the flywheel, if you want to slow down your accessories then put larger pulleys on them.

It means a lot of failures in a lot of engines, not just Miata oil pumps.

If you could do an underdrive while keeping the harmonic damper ability, that's best. Or eliminate the belt driven water pump and go with a beefy electric, no worries about cavitation at high RPM anymore.

I remember a Saturn racer guy did a test with underdrive pulleys on a dyno and found no difference (within measuring error) between stock, underdrive, and no belt at all. Don't underdrive for power, underdrive to make the accessories last or to get the water pump working in its efficiency range.

(Say, didja know a stock 12A pulley set cavitates the water pump at only 6000rpm? Not a problem with a 7000rpm redline, major problem when the revs DROP to 5500-6000 after a shift)

rslifkin
rslifkin Dork
6/15/17 7:44 a.m.
Keith Tanner wrote: There's more demand for dampers that are more effective than stock, and there's a minimum size for that sort of thing. Oil pump failure sucks a lot more than spinning your water pump at the speed Mazda intended

That's why I was thinking of an American V8 style damper. Damper is whatever size it needs to be, pulley bolts to the front of the damper. So the damper can easily be bigger than the pulley without causing any conflicts.

Keith Tanner
Keith Tanner GRM+ Memberand MegaDork
6/15/17 7:58 a.m.

That'll work if your belts have some standoff room from the front of the motor. On a car with tight packaging, they're usually snuggled up against the block so there's no room for a damper between the block and the pulley. The damper is inside the pulley. The LS engines, for example, have an extra 3/4" behind the belts on a truck setup than they do on a car setup.

We use an ATi damper for our high performance Miata stuff. Works great, but it's as small as it can be.

Rumnhammer
Rumnhammer Reader
6/15/17 8:02 a.m.
Keith Tanner wrote: There's more demand for dampers that are more effective than stock, and there's a minimum size for that sort of thing. Oil pump failure sucks a lot more than spinning your water pump at the speed Mazda intended

Yes it does. I work at ATI and I can't tell you how many people call and want to run an underdrive damper on their car, (usually corvettes) because they read on some forum that they can get an extra 5hp at the expense of the extra harmonic damping they would get from a proper sized damper. I usually ask them if they can feel a differnce when they turn on their ac in a vette that's making 500hp. When they say no then I tell them that the ac is taking more hp then they would gain with the underdrive and they would be ahead of the game to go with a OEM size replacement. Especially in a corvette which requires $1000+ in labor to install when the engine is in the car. Seriously I tell people this on a nearly daily basis.....

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