jimlab

My puzzlement was why someone would "punch it" in 4th gear when only traveling 45 mph.

Perhaps I should have added the qualifier "under boost/high load". Accelerating at part throttle through the normal cruising range off-boost will not cause problems, obviously. Allowing boost to creep up in higher gears because of load while accelerating at part throttle (i.e. not WOT) is what I'm talking about, and it's generally accepted that this is a no-no, at least with the factory ECU.

jimlab

I think you meant ridiculous. And you're right, it is ridiculous that people still try to convince themselves (and others) that the FD is reliable in light of the number of engine failures it has accumulated. No other sports car that I know of has the concept of "reliability mods" associated with it, which pretty much says it all.

turbojeff

iTrader: (30)

I think I understand what your saying but I'm not sure I think it is correct.

Boost is the result of load so I interchange the terms.

I'd agree high load, low rpm boost gives a lean condition with the stock ECU, ie under 2500rpm and in many cases is a bad idea, esp in the higher gears like you mention.

At other rpm ranges (above 2500rpm) I don't see the problem with part throttle acceleration with boost in any gear. I've run a wideband on my car and IIRC it goes full rich any time the ECU sees boost.

poss

iTrader: (5)

Oh no, spelling queen is on my ***. You need something better to do with your spare time...I'm serious.

I by no means said that it was a reliable car. Anyone who knows anything about FD's knows that the engine is very likely to need to be replaced before the 100k mark, many before 60k. That's why they're cheap to rebuild. The old saying "The candle that burns twice as bright, burns half as long" should have been on the window sticker.

That comment was mainly directed to the posts as of late about the cold being bad for the rotary. Other than an increased chance of flooding, it handles cold just fine. And now the preposterous claim that running part throttle on an otherwise properly maintained car is gonna "blow yer motor!" What has this forum come to?? Old bitter ****** and young lazy asses w/o any common sense?

scotty305

iTrader: (2)

This is an interesting thread. Here is a photo that might be useful for this discussion:

...carry on...
-s-

scotty305

iTrader: (2)

^^Quote of the year. I'm sure that most of the 'bitter ******,' as you so delicately put it, weren't always that way, but the steady flood of the young lazy asses caused them to become that way. I blame pop culture, especially television, crappy public schools, and professional sports. And people who use the internet but can't spell correctly.

[/off topic]

-s-

FadedFD

iTrader: (3)

Im just glad there is always people with different opinions to discuss issues like these. We all learn from each other. I'm a newb so it helps alot.

dubulup

Don't worry brother, you will NOT blow your engine at part throttle accelaration.

TwinTurbo_SE7EN

What about brake boosting? I hold down the brake and gas in first gear to maintain ~20 mph and build boost to about 3 psi. that puts me at about 3800-4000 rpm starting out. then its off with the brake and WOT. is this bad?

TEDDER1

iTrader: (1)

I skimmed through this thread but I think I know what he originally was saying. In my hooptie, if I give it ~30% throttle it'll haul complete ***. If I floor it the car just goes but not like partial throttle.

I have showed several people and let them try it out... But mines some freak according to everyone who's been in it. (serious)

PLEASE NOTE I am talikng about launching @40mph in 2nd...

PhoenixDownVII

While nobody directly responded to my post, I suppose what I was aiming at was somewhat true, and very important to mention.

And it's common sense, if you're in 4th going 45mph UP a hill, why would you go full throttle? You'll notice your car is hardly getting anywhere fast, and it would make sense to downshift to start accelerating from a higher rpm anyways.

If you drive your FD like that I guess it deserves to be blown anywho, a sports car is meant to be DRIVEN, not cruised around like a towncar trying to pinch out all the gas mileage you can get out of the thing...

Les

You guys are doing a great job, thanks for all the info. As a new Rx 7 owner I am learning alot and questioning how the car performs and don't want to blow it up any earlier than necessary(humor). So an A/F gauge would tell you under partial accelerating throttle that you were running lean and under WOT that you were running rich?

Also the poor guy who spelled ridiculous wrong was, I thought impersonating Mike Tyson.

turbojeff

iTrader: (30)

In reference to the ECU fuel "zones" those pressures on the the left must be in absolute pressure, otherwise they are off the map boost pressure wise. The "heavy load zone" is actually is a very narrow operating zone. 27.7inHg = 13.6psi. Atmospheric pressure is about 14.7 psi so that would be a very slight vacuum reading on the boost guage. 32.7inHg = 16.1 psi, so that would be a 1.4 psi boost on a guage.

It is very hard to run a sequential FD at any boost level below a few psi with any acceleration so I'd say that graph agrees with my wideband experiences.

Part throttle acceleration under boost above ~2500 rpm the ECU goes full rich and there is nothing to worry about.

turbojeff

iTrader: (30)

Cutting out the "fuel cut zone" which is off throttle operation and the boost zone. You see that ECU map is a narrow range of engine operation. It seems to be the "emissions zone" or closed loop operation, it also is noted as the narrow range on the TPS. This represents regular cruising.

turbojeff

iTrader: (30)

No, part throttle accel on a FD = boost operation for any moderate level of throttle opening. That graph only shows very narrow throttle opening. This means the ECU goes full rich after about 2500 rpm based on wideband testing.

Jeff

poss

iTrader: (5)

Don't make me bite your ear off!!

That makes sense Jeff. I was thinking those numbers were screwy.

dubulup

I've got lots of respect for Jim's skills and everything, but sure didn't think that was a very accurate statement.