Gears 2!

[90Notch]

Raph130 thought you might find this interesting. Here's a portion of the code off my stock A9L EEC program:

PIP 961 # Minimum PIP period (PIP = 6250/maxRPM)HALF_FUEL_REV_LIMIT_ON 8000 # Turn on half-fuel rev limit
SECOND_SPEED_LIMITER_ON 134 # Turn on 2nd speed limiter (MPH)
SECOND_SPEED_LIMITER_OFF 134 # Turn off 2nd speed limiter (MPH)
FIRST_SPEED_LIMITER_ON 134 # Turn on 1st speed limiter (MPH)
FIRST_SPEED_LIMITER_OFF 134 # Turn off 1st speed limiter (MPH)
NO_FUEL_RPM 7000 # Max RPM (no fuel)

Take note of parameters in bold, do you still think you hit 145 MPH?

 

[5spd GT]

I'm not to sure why the Gear thread got locked but this is in response to Michael's post...I'll quote him...

"5spd - all you have to do is read magazine tests over the years to see the discrepancies in performance that have rolled out of the factories year after year. Of course there are performance discrepancies - sometimes quite large. No, they would not all perform the same. +/- 8-12% isn't an usual performance difference at all - which makes a big difference on dyno, the track, and in top speed. It's amazing to me that they're as close in performance as they are when you look at the complexity of the product the manufacturers are producing. And they're MUCH better today than they were even 10-15 years ago. "

Are you comparing factory freaks to magazine tests? That is even "worse" in the "discrepancies" on judging factory freaks or not...there is different drivers/trans/conditions/head wind...

I know on the 05 Gt's...they test each car after final assembly for any "discrepancies" which alludes back to your "10-15 years" conditioning...

 

[jb89coupe]

That's weird, I have a refurbished (from ford) a9l in my car, and I've had my "certified calibration" 160mph speedo past 140 once or twice. This was with the stock gears, stock tire size still. My car doesn't appear to be governed...? It's a special service car, but like I said the computer is a refurb a9l. I guess my speedo could have slipped calibration or something.

 

[raph130]

*

 

[5spd GT]

YES. 87-93 mustangs are not speed governed. plain and simple. any 5.0 stang can hit over 140mph in a 5 speed. 140mph is the SAFE top speed ford will announce, when in fact the car has no problem getting to 150 even with stock gears and power. if they are then every stang ive had has had this feature disabled. because i ahve reached 145mph at least in every single one of them. i know what a fuel cut off feels like i have had very pesky turbo cars have this feature, and i have never experienced it on a mustang. so stuff your made up proof down your throat.

Please quit posting..."pretty please"?

 

[cleanLX]

90notch,
maybe you should have someone explain what that code is doing.
Because, it's not shutting any systems off at 134.

Rags of the day routinely ran the cars out to 140-142mph.
Guy in our club has been verified over 150mph by, yep, a Gixer.
Another guy in our club has been verified by AEM over 150 having not altered any "speed limiter"...

It's also interesting how the code turns on and off the limiter at exactly the same speed, and, has no code saying what exactly is cut at 134.

I've been told, the EEC has all kinds of useless crap writen into, and this apears to be some of it.

 

[89MustangGX]

Top speed limiter: my understanding is that it's in there, but it's not activated. Why, I don't know -- but that's what I've heard.

As for hitting those top speeds, I believe one can hit 140(ok, I know), but 150 or beyond, I wouldn't believe it unless you were talking downhill with a tailwind.

 

[90Notch]

"90notch,
maybe you should have someone explain what that code is doing.
Because, it's not shutting any systems off at 134."

Well atleast I'll admit when I wrong for this function to work the ON setting has to be set higher than the OFF setting. It's a built limiter that has to be turned on default is set off. When turned on it shuts off motor when speedometer hits listed speed. Been awhile since I've played with it, my bad.

Others are self explanatory, Fuel cutoff cuts fuel at rpm & PIP is a sample frequency that limits the PCM program (i.e rev limiter)

 

[Michael Yount]

5 spd - many magazines test similarly equipped cars - sometimes because the manufacturer provides multiple examples; sometimes over several model years when the car changed very little. They account for the kinds of differences you spoke of, and their testing protocols help eleminate the kinds of discrepancies you're referring to. Yes - there's a wide range of performance on cars that roll out of anyone's factory. Granted most of the cars perform similarly - but you definitely get the odd few that run really well or really poorly.

Then this - "I know on the 05 Gt's...they test each car after final assembly for any "discrepancies" " -- they don't test for peak performance discrepancies. They have a pre-programmed electronic systems test along with a brief run up on a set of rollers. It confirms that systems are working as they're supposed to - you know - the back up lights come on when the car goes in reverse, sensors are working properly - those sorts of things. Tests like that last about 2 or 3 minutes before the vehicles are rolled off and into the temporary storage area for shipping. They're not checking to be sure they hit some preset HP or 1/4 mile number. There are very few manufacturers that do any extensive testing of that nature. AMG (Mercedes hot rods) is one that does on some of their engines - each of the 5.5L supercharged engines they build (around 495HP/580 lb-ft torque) gets dynoed to be sure it hits the advertised HP/torque BEFORE it goes into the car. But that's one of the reasons those cars cost just a few dollars more than your garden variety new $25k Mustang.

 

[Michael Yount]

Anyone know what the speed rating of the standard tires that came on the 5.0 fox bodies were? That's the usual reason for speed ratings. You'll frequently see speed limits in systems of 112 (S speed rating), 118 (T speed rating) or 130 mph (H), and those just happen to correspond to the common speed ratings of some tires. Back in the late 80's/early 90's we didn't have the selection of tires we do today. It was pretty much H (130 mph) or V (149). Today we also have W (270 kph/168mph) and Y (300 kph/186 mph). The new GT is both top speed limited (I just read the test but I can't remember where - somewhere in the 130's); and it also has software activated that severely limits tire spin. Burn outs essentially are eliminated. You can dry hop it, but when the software detects tire speed in excess of real speed for more than a second or two, it closes the electronic throttle to eliminate the situation. That's right - you need a chip to uncork the real top end or to do a burnout. Why? Warranty cost control and legal liability. It'll be interesting to watch what happens as folks start disabling those systems and then trying to make a warranty claim. Subaru and Mitsubishi are catching some flak for monitoring SCCA's public listings of autocross results, identifying drivers who are racing their cars, and disallowing their warranty claims. Big brother (oem's) is watching.

In Germany, the oem's agreed to not have an all out autobahn top speed war, and despite the fact that Audi, VW, Mercedes, BMW and Porsche all make cars capable of top speeds in the 170-180 area (some even more), over there they agree to limit them to 250 kph - a tick over 155. Of course one of the first things done is to find a tuner to undo the speed limiter.

Limiting codes like those shown above are almost always written in to allow future flexibility even if it's not active on a certain model. My guess is the old foxes came with H-rated tires, not V's. But it's just a guess. And since Explorers had not yet started rolling over from (poor driving right after a) tire failures, perhaps Ford didn't feel the need to activate the speed limiting code.

 

[jwzg]

Mike, the tires from 1985-90 were Goodyear Eagle VR Gatorbacks. From 1991-1993 either ZR Gatorbacks or Michelin XGT Z4's (ZR) were the flavor of the day. My car had the latter.

Motor Trend topped one 1987-88 Mustang out at 148 mph on in Fort Stockton, TX. It's been a while ago, but I remember the Mustang was only 1 mph shy of the IROC 350 tested at the same time. I do remember that in subsequent top speed tests, the Mustang inexplicably posted lower numbers every year until 1993 where I believe most rags were quoting around 135. Hell Motor Trend ran a 1995 Cobra on "Mrs. Orcutt's driveway" in a top speed test and it didn't even make the 140mph cutoff for the test.

 

[Michael Yount]

Thanks - well the speed rating on the tires certainly allowed for no limit in the computer. Since Bridgestone/Explorer, that's probably changed.

 

[jwzg]

Mike that's my guess as well. The '93 Cobra's cut timing and richened the fuel mix above 93 mph, so top speed was definitely an issue as early as then. Don't even make me talk about the SN Cobra's. Their EEC's are deservedly maligned.

 

[juniordog]

Top speed limiter: my understanding is that it's in there, but it's not activated. Why, I don't know -- but that's what I've heard.

As for hitting those top speeds, I believe one can hit 140(ok, I know), but 150 or beyond, I wouldn't believe it unless you were talking downhill with a tailwind.

did anyone else find this post kinda funny? just because u are going downhill with a wind doesnt mean your car can go faster. you engine still has to keep up with the speed of your wheels...

 

[Michael Yount]

junior dog - top speed achieved is DEFINITELY impacted by terrain and wind speed/direction. The main thing a car has to overcome to achieve higher speed is aerodynamic drag. If you have a 40 mph tail wind, the car's gonna be able to achieve a higher road speed than if there were no wind, and even less if it's running into a head wind. Downhill - well that's pretty easy to figure out. Set the on level ground with no wind with the engine off in neutral. It will just sit there. Set the same car on a 10% grade with the engine off and in neutral - it'll keep increasing speed until the aerodynamic drag (and other lesser frictional drags) created overcomes the pull of gravity on the car. Zero engine speed.

Yes. A car will achieve a faster top speed going downhill with a tail wind.

I found your post kinda funny.

 

[5spd GT]

5 spd - many magazines test similarly equipped cars - sometimes because the manufacturer provides multiple examples; sometimes over several model years when the car changed very little. They account for the kinds of differences you spoke of, and their testing protocols help eleminate the kinds of discrepancies you're referring to. Yes - there's a wide range of performance on cars that roll out of anyone's factory. Granted most of the cars perform similarly - but you definitely get the odd few that run really well or really poorly.

Ah...I still don't buy the factory freak idea...to many variables

Like I said in the original gears post...if you look at rsw007/25ths/cleanlx/89sleeper/ they all are making the power numbers they "should" because they have been on a dyno...and rsw007 is ALMOST in the 12's with 210rwhp...how is that factory freakish? Just good drivers and lower weight...

I bet that again if two 5.0L 5spds/same options (a/c and all)...same stock base timing/octane...same gearing...etc..etc...and even had the same two bugs stuck in their air filter and the same outside conditions...I bet they would dyno within 5hp...but of course we will never find out...

I know on 90MustangGT's friends car (I'm getting reflections of Raph130 - "friend")...anyways...I know his friend has/had an lt1 and it was always beating cars it shouldn't be like the overall more powerful ls1...and the previous owner told him the engine was untouched...well later on in the cars life they tore the engine down for something and found out the heads were worked on...and all along they thought they had a "factory freak"...in short you never really know what the previous owner did...

On the 05's...they don't hook up anything that would trip them to any kind of sensor that could show where the power might not be there like it should (a/f ratio?)...?

 

[cleanLX]

Top speed limiter: my understanding is that it's in there, but it's not activated. Why, I don't know -- but that's what I've heard.

As for hitting those top speeds, I believe one can hit 140(ok, I know), but 150 or beyond, I wouldn't believe it unless you were talking downhill with a tailwind.

Neither car had near a stock motor, simply stock computer, er, at least no fideling with the "speed cut out" in the stock computer.
Example, one puts out over 600hp/700tq to the rear wheels running dart block and a fancy hair dryer.
The other was actually verified at over 170... 180 'indicated' on the Gixer.

Well atleast I'll admit when I wrong

Something we should all learn to do... :salute:

 

[juniordog]

junior dog - top speed achieved is DEFINITELY impacted by terrain and wind speed/direction. The main thing a car has to overcome to achieve higher speed is aerodynamic drag. If you have a 40 mph tail wind, the car's gonna be able to achieve a higher road speed than if there were no wind, and even less if it's running into a head wind. Downhill - well that's pretty easy to figure out. Set the on level ground with no wind with the engine off in neutral. It will just sit there. Set the same car on a 10% grade with the engine off and in neutral - it'll keep increasing speed until the aerodynamic drag (and other lesser frictional drags) created overcomes the pull of gravity on the car. Zero engine speed.

Yes. A car will achieve a faster top speed going downhill with a tail wind.

I found your post kinda funny.

i understand what you are saying and i definatly agree. i guess my understanding of this arguent was that top speed = redlining in 5th. i guess i misunderstood. i've never taken my car to top speed, so im really just talking from a logical point of view rather than experience.

 

[Michael Yount]

I understand dog - you're right. It was discussed earlier in the thread. Very few contemporary cars are geared to hit top speed in top gear. The car is usually geared to help it with fuel mileage and won't pull enough revs in top gear to get anywhere near it's top speed. The C5 Corvette is a great example. Top speed achieved in 5th gear. Shift to 6th at top speed, and the car slows down because the engine's turning too few revs to make enough power to hold it at the top speed. Same thing happens on stock Mustangs with 2.73 gears. Top speed in 4th. Shift into 5th, and it slows WAY down.