dre_2ooo

well now that I'm a "racer" (Solo II), I have been doing LOTS of heel-toe downshifting.

Of course, sometimes this can from from 3rd to 1st gear. SO i'd be in 3rd, d/s to 2nd using heel-toe, D/S to 1st using heel-toe and take the corner blah blah blah.

Of couse, then engine is in gear durning heavy breaking and foot is off accelerator, so the throttle plates must be closed. I'm thinking that the fuel injectors cut fuel alot too. Since my oil is IN my gas, can this possibly be causing underlubrication since not as much fuel as normal is getting to the apex's/housings as normal at such high RPMs? What about the OMP at this state?


Curious/Paranoid I guess.

f331

the engine cuts fuel due to the low ammout of air entering the engine

dre_2ooo

Damnit that's what I was afraid of. How will his hurt lubrication-wise? (I am running premix in conjunction w/OMP)

f331

not positive, normaly in these situations a engine will run a little leen but you can tune it to fix that so it shouldnt be a big deal

Roy James

if the engine is running.... its getting fuel. At idle the throttle plates are closed.... correct?

HAILERS

Go to the 89 manual online, and look in the Fuel section, page F-77. Tells you when the primary and secondary injectors are ON/OFF. HTTP://WWW.FC3S.ORG

The primary fuel injectors have their fuel cut during deceleration (throttle valve fully closed). Caused by the tps sensing that condition i.e. fully closed throttle.

dre_2ooo

OK, well my next question, can/does this hurt the engine at all? (Being used in racing application of course)

deadRX7Conv

What is Mazda's definition of fuel cut? They are you rich/lean/off and then fuel cut on that chart. Or is it just "cut" to the amount that is needed at idle or for the amount of air entering. At no point is fuel eliminated because the catalytics would cool down too much and this would increase emissions when you stomp on it again.

This is the first time that I've heard someone ask about lubrication during engine (compression) braking. I would hope that the Mazda engineers took this into consideration and either there is enough residual oil left or that the "fuel cut" still allows enough fuel/lubrication during engine braking. We all have driven down a hill at least once, right? I wouldn't worry about it because your MOP is working and you are running premix insurance.

What's your definition for heal-toe? My ankle and foot size doesn't find the RX7 comfortable for heal/toe driving.

HAILERS

I'm no expert, but frankly I doubt it very much. (On a normal car when you let off the throttle, the omp lever moves to its idle position where there is little or no oil metering flow (just pull one of the four metering bolts at the pump to see this). Just my wag. Talking up to a 88 model. Know not about 89 and up.

dre_2ooo

Ok, I guess I'll just keep up the good driving