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Location:
Sydney
Registered:
July 2002
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 What is a "red line"
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Fri, 24 January 2003 00:48
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Talking about rev limits of the 1uz I want to know: What is a "red line".
I know from looking at various dyno outputs that power drops off after hitting its peak. Some drop off quicker than others.
I'm thinking a good definition would be:
Where the engine is past its ability to make power.
OR Is it more:
Safety level for engine as components and fuel system can not cope with revving more than this point.
Also I know that with forced induction you can make an engine rev more and increase the rev limit. Is this true?
In gone in 60 secconds when he's in the flood drain and hits the NOS, he stays in the same gear, is this just pushing that gear a little further as the engine has ran out of puff (dropped off the back of the power curve)?
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I supported Toymods
Location:
Perth
Registered:
May 2002
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Re: What is a "red line"
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Fri, 24 January 2003 00:50
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I'm assuming with forced induction, that its because you are forcing air through the engine, it overcomes some of its breathlessness, as the intake is usually one of the most restrictive parts of an engine.
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Location:
Cabramatta, NSW
Registered:
May 2002
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Re: What is a "red line"
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Fri, 24 January 2003 01:48
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| HKSPete wrote on Fri, 24 January 2003 11:48 |
Also I know that with forced induction you can make an engine rev more and increase the rev limit. Is this true?
In gone in 60 secconds when he's in the flood drain and hits the NOS, he stays in the same gear, is this just pushing that gear a little further as the engine has ran out of puff (dropped off the back of the power curve)?
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That only works when you have two bottles of NOS instead of one that's twice the size.
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Location:
1st street on the right
Registered:
November 2002
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Re: What is a "red line"
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Fri, 24 January 2003 22:43
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People may correct me if I'm wrong. I have always taken it to be the max revs for the engine as it is built. Forcing the induction may increse the revs but if it hasn't been built to take the extra load from this then it won't last long (ie turboing a high compression engine)
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Location:
Sydney
Registered:
May 2002
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Re: What is a "red line"
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Sat, 25 January 2003 02:52
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LoL my 1J dosn't know what a redline is either  i couldn't belive i was bouncing the needle at 7600
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Location:
Brisbane
Registered:
January 2003
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Re: What is a "red line"
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Sat, 25 January 2003 10:48
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I always thought a "Redline" was when you're reaching the rotation limit of the engine, if you go further you risk mechanical failure.
(That doesn't mean it won't go above a redline 
As far as I know forced induction does not increase a redline, just helps get you there quicker.
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Location:
Barossa valley SA
Registered:
January 2003
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Re: What is a "red line"
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Sat, 25 January 2003 12:13
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I always thought that the redline was the point that the manufacturer recomended that you dont rev past for the safe operation and longer life of the engine?
Also I dont know about everyone else out there but I am always a bit sceptical about automotive things I see in movies, especially after seeing the fast and the furious. (by the way have I been out of the loop because I just heard there is a sequal to that movie in the pipeline.)
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Location:
Barossa valley SA
Registered:
January 2003
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Re: What is a "red line"
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Sat, 25 January 2003 12:15
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One more thing what is the redline for a 7MGTE?
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Location:
Lost in the K hole
Registered:
May 2002
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Re: What is a "red line"
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Sat, 25 January 2003 13:53
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redline is where you risk mechanical failure due to the inherent design characteristics of your specific engine: ie stroke length, rod length, stroke rod ratio, rod material, crank shape, weight, counterbalancing, piston weight, crown height... etc etc.
it is also the point where the engineers have found harmonics would start to affect other things like valve springs, valve bounce etc etc.
forced induction, NOS and all that shit doesnt change the redline ONE IOTA! what is does change is the power output of a given engine design/capacity/VE and lets you reach your redline much faster. thats all.
engines tend to "run out of puff" on the dyno because their cam is deisigned to work within the given rev range of the engine, and outside that rev range, it doesnt work - thats why the engine output drops off approaching/after redline. if you change your cam, you can shift the power curve around. but if you want a cam that works beyond your engines redline, you have ONE HELL of a tasks at your fingertips prepping the rest of the engine to handle it. and some stuff, like stroke/rod ratio is not changed easily, or without big $$
cheers
ed
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Location:
Lost in the K hole
Registered:
May 2002
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Re: What is a "red line"
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Sat, 25 January 2003 13:55
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7mgte redline : around 6800 (v.BAD stroke rod ratio)
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Location:
Southern Sydney
Registered:
August 2002
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Re: What is a "red line"
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Sat, 25 January 2003 15:04
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Depends what your driving.....
If its a Super POS crapbox that you don't care at all about then its a fraction short of valve bouncing. (right before you sidestep off the clutch )
If it is anything with a dollar value or that has any meaning whatso ever it is significantly short of this though!!!
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Location:
Sydney
Registered:
May 2002
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Re: What is a "red line"
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Sun, 26 January 2003 23:45
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i had my old 7m up around theree many times
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Location:
Lost in the K hole
Registered:
May 2002
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Location:
Sydney
Registered:
May 2002
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Re: What is a "red line"
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Mon, 27 January 2003 01:08
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from memory it was inbetween 7000 and 7200 but the fuel had to be really good else the thing would get the shakes i normally would put mobile8000 and half a bottle of race formular octane booster and the thing had no probs reving hard...it was a beutiful engine and less tiersome to drive around....but when the 1J open up its a whole other story 
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