The Oldsmobile Connection

85cieraholiday · Posted: Fri Jan 19, 2007 12:43 pm Post subject: Re: MAX RPM...3.8L?

88 Coupe wrote: 85cieraholiday wrote: Link about Honda speedometers
Tell us why you would consider epinions.com (or that anonymous post) a credible source?

Quote: ........ If you do a Yahoo/Google search ........
Me? Search the internet for accurate information? Shirley, you jest.

Quote: ........ there are thousands of similar complaints by owners.
Founded or unfounded. Or are they just passing along another Urban legend?

Suppose it is true. Are all the "ricers" going 10% faster than they think they are?

Or, did they start the story to justify their exaggerations.

Norm

The epinions.com link is just to show 1. I am currently looking for the news article and 2. There are some owners who claim to have this issue.

"If you do a Yahoo/Google search "

This didn't mean everyone here should do a google search, I just wanted to show everyone the path I took to start my search for documented info.

The more I think about it there may have also been an article in a mag (Car and Driver maybe?) where I read this also about an Acura.

The search continues.

85cieraholiday · Posted: Fri Jan 19, 2007 1:25 pm Post subject: Re: MAX RPM...3.8L?

Test results

Car and Driver article

Honda looses due to odometer inaccuracy

VW TSB

Car Talk-We did find that the speedometer seemed to be very inaccurate.

88 Coupe · Posted: Fri Jan 19, 2007 6:09 pm Post subject: Re: MAX RPM...3.8L?

85cieraholiday wrote: ........ Test results
Good source, in this case. The others are less than good.

caranddriver.com wrote: ........ Variations in tire size and inflation levels are the sources of error these days. Normal wear and underinflation reduce the diameter of the tire, causing it to spin faster and produce an artificially high reading. From full tread depth to baldness, speeds can vary by up to about two percent, or 1.4 mph at 70 mph. Lowering tire pressure 5 psi, or carrying a heavy load on the drive axle, can result in about half that difference. Over inflation or oversize tires slow down the speedometer ........
Here we see why absolute accuracy cannot be expected, and any rule must have tolerances included.

88 Coupe wrote: TheLSS wrote: ........ Manufacturers put the speedos so they read ahead that 15% to keep people from speeding and not even knowing it ........
I cannot speak for Canada, but that does not happen in the US ........
Read what is there: "15% to keep people from speeding".

Norm

88 Coupe · Posted: Fri Jan 19, 2007 6:56 pm Post subject: Re: MAX RPM...3.8L?

To address the original question:

sean000 wrote: Anyone know what max rpm (red line) is on my 83 Cutlass 3.8L V6?
Depends on your definition of "red line".

Back in the day, it showed the end of the max safe operating RPM for that engine. There was another line below it to indicate the "theoretical" shift point for max performance. And, in some cases, still another to mark a spot for "normal"/"cruising"/"economy" shifts.

What it means now, can be anyones guess.

If you are looking for a "shift point", that would be a different topic than is being discussed.

Norm

88 Coupe · Posted: Fri Jan 19, 2007 7:15 pm Post subject: Re: MAX RPM...3.8L?

TheLSS wrote: ........ I was reading the information from a GM Tech 2 OBD 2 Scantool under the live engine monitoring mode ........
OK. We can assume, as you have, that your instrument was accurate.

Quote: ........ well, as well as I could see it it was ........ Quote: ........ It fluctuated when idling so I couldn't get an exact reading ........
However commendable your honesty is, it seems to contradict your previous statement.

Norm

88 Coupe · Posted: Fri Jan 19, 2007 7:30 pm Post subject: Re: MAX RPM...3.8L?

Erroneous Restrictionism! wrote: ........ I still answered the question that was at hand ........
I repeat: You have not shown any reason why we should believe your answer to be factual.

If it is not fact, it is lie.

A lie is far worse than no answer at all.

Erroneous Restrictionism! wrote: ........ call it whatever, it's still happening at "the redline"...
And you still have not given the year, make and model of the car you are talking about.

Until you can do so, you are wasting bandwidth.

88 Coupe · Posted: Fri Jan 19, 2007 9:01 pm Post subject: Re: MAX RPM...3.8L?

TheLSS wrote: ........ Just about any car ........
Can you name which do, and which do not? Can you give us any semi accurate percentages?

If you cannot supply either, your statement is worthless.

Quote: ........ has an RPM limiter that is either mechanically controlled or controlled by the ECU ........
When did the practice begin?

Quote: ........ Manufacturers don't want pistons flying through the hood when the driver accidentally ........
Can't argue with that logic.

Quote: ........ it's a safeguard that's relatively simple yet does a lot ........
What methods were used, during the Nineteenth and, throughout the Twentieth Century?

Norm

88 Coupe · Posted: Fri Jan 19, 2007 9:21 pm Post subject: Re: MAX RPM...3.8L?

TheLSS wrote: andrewk wrote: ........ Not true in the least. My car ........
Ah, thought GM might have done something like this.
You thought? As in, did not know?

Norm

andrewk · Joined: 18 May 2005 Posts: 1246 Location: Ames, IA

TheLSS wrote: Erroneous Restrictionism! wrote: TheLSS wrote:
If you want to find out how high these engines can go, put the car in park or neutral, and hit the throttle till it bounces off the rev limiter, then you see where the governor kicks in, and voila, sean000 has an answer!

Does my car even have a limiter?...I still answered the question that was at hand but some don't think it's good enough.
call it whatever, it's still happening at "the redline"...

Just about any car has an RPM limiter that is either mechanically controlled or controlled by the ECU(unless it has been removed by the owner). Maufacturers don'w want pistons flying through the hood when the driver accidently puts the vehicle in neutral, or accidentally guns in when they get in thier car when it's in park, and it's a safeguard that's relatively simple yet does a lot. E.R., have you removed the rev limiter in your car? I believe your car has an ECU controlled rev limiter, so unless you have a chip in that thing, you will have a rev limiter. And we don't think it's not good enough, we know it's not good enough :wink: .

andrewk wrote:

Not true in the least. My car, albiet not a 3.8 hits the limiter at 4000 in park, shifts at 5500 or so in drive. I'll bet that your cars are the same, or at least similar, but I don't know for sure.

Andrew

Ah, thought GM might have done something like this. What does your car rev to in Neutral?

Gave it a test tonite, rev limiter is right about 4k in both neutral and Park.

TheLSS · Joined: 10 Jan 2007 Posts: 30 Location: Canada

88 Coupe wrote: TheLSS wrote: andrewk wrote: ........ Not true in the least. My car ........
Ah, thought GM might have done something like this.
You thought? As in, did not know?

Norm

Naw, I just didn't mention it earlier because I did not think these cars would do this, but it was still in the back of my mind. I only know so much at this point in my career.

88 Coupe wrote: TheLSS wrote: ........ Just about any car ........
Can you name which do, and which do not? Can you give us any semi accurate percentages?

If you cannot supply either, your statement is worthless.

I cannot give you any semi accurate percentages sadly, but I do know that every car I've driven or ridden in has one. I don't know of a vehicle that doesen't. Allthough that can't be saying much.

88 Coupe wrote: TheLSS wrote: ........ has an RPM limiter that is either mechanically controlled or controlled by the ECU ........
When did the practice begin?

Absolutely no clue, all I know is that they're used.

88 Coupe wrote: TheLSS wrote: ........ it's a safeguard that's relatively simple yet does a lot ........
What methods were used, during the Nineteenth and, throughout the Twentieth Century?

No clue, history isn't my strong point, it's why I became an auto mechanic :wink: .

88 Coupe wrote: TheLSS wrote: ........ well, as well as I could see it it was ........ TheLSS wrote: ........ It fluctuated when idling so I couldn't get an exact reading ........
However commendable your honesty is, it seems to contradict your previous statement.

Norm

The only reason I couldn't get an exact reading was because it fluctuated 50-100 RPM because it was idling, and I cannot read the information within the millisecond to get a exact reading. I gave an average to cover what RPM the engine was theroetically idling at. FYI though, the target Idle RPM the Tech 2 showed was 675 RPM, which the ECU was trying to keep the engine at, and doing a pretty good job of it too. As contradicting as that may be, it still proves my previous points. The Tech 2 showed the exact RPM the vehicle was at as quickly as the computer could calculate it, but the tachometer on the dash did not, it was stable at 1000 RPM. And as for the as well as I could see it thing, I should have been more specific, it was in a 1997ish Pontiac Grand Am GT, and the dash on those things has got to be the worst ever for accurate visibility in the daytime. The spherical design just sucks IMO.

andrewk: Crap, there goes my theroy of finding the true rev limit of these things in neutral. If I get a chance to hook the GM Tech 2 up to a 3.8, I'll tray and find the rev limit that the engine is set at and report back.

Erroneous Restrictionism! · Joined: 02 Jun 2004 Posts: 266

andrewk wrote:

Gave it a test tonite, rev limiter is right about 4k in both neutral and Park.

And you also have a '91 3.1 litre....I don't have a limiter....

88 Coupe · Posted: Sat Jan 20, 2007 2:05 am Post subject: Re: MAX RPM...3.8L?

TheLSS wrote: 88 Coupe wrote: TheLSS wrote: andrewk wrote: ........ Not true in the least. My car ........
Ah, thought GM might have done something like this.
You thought? As in, did not know?
Naw, I just didn't mention it earlier because I did not think these cars would do this, but it was still in the back of my mind. ........
In the future, before you answer one of my questions, think about it and how it relates to the quote. Is there anything you can learn from the question? I hope so, because I do not ask them just to read your excuses.

Read the above exchange, and see if you get my point.

Quote: ........ I only know so much at this point in my career ........
Yes. We are still, well aware of that fact.

88 Coupe wrote: TheLSS wrote: ........ Just about any car ........
Can you name which do, and which do not? Can you give us any semi accurate percentages?

If you cannot supply either, your statement is worthless.

TheLSS wrote: ........ I cannot give you any semi accurate percentages sadly, but ........ I do know that every car I've driven or ridden in has one. I don't know of a vehicle that doesn't ........
Do you see my point yet?

TheLSS wrote: Although that can't be saying much ........
That would be my point.

Norm

sean000 · Posted: Sat Jan 20, 2007 9:55 pm Post subject: Re: MAX RPM...3.8L?

88 Coupe wrote: To address the original question:

sean000 wrote: Anyone know what max rpm (red line) is on my 83 Cutlass 3.8L V6?
Depends on your definition of "red line".

Back in the day, it showed the end of the max safe operating RPM for that engine. There was another line below it to indicate the "theoretical" shift point for max performance. And, in some cases, still another to mark a spot for "normal"/"cruising"/"economy" shifts.

What it means now, can be anyones guess.

If you are looking for a "shift point", that would be a different topic than is being discussed.

Norm

I was looking for max safe operating range. The shift point would be nice to know as well.

88 Coupe · Posted: Sun Jan 21, 2007 2:12 am Post subject: Re: MAX RPM...3.8L?

Hi sean000,

Good to see you're still with us.

Quote: I was looking for max safe operating range ........
By design, it is not capable of revving that high.

Quote: ........ The shift point would be nice to know as well.
The number will vary, depending who is doing the talking.

It will nearly always be based on the RPM where the peak HP occurs, and will be stated as (xxxxx+y %) ex: 5000 RPM + 10%, or as (xxxxx+z) ex: 5000 + 500 RPM.

That would be a good place to start. At what RPM does your peak HP occur?

Norm