redline

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umm.... what does your tach say???

if you want to know the fuel cut-off then hit your gas in neutral and see when it popcorns
 
popcorns?? lol

the 88-91 civic LX had a 1.5 D15B2 which has a 6800rpm redline.

the 88-91 civic si engine 1.6l D16A6 has a 7100rpm redline.
 
I'm new to this - as you can see. but is that bad to redline your engine - I mean I know that it'll ruin it if you do for a long time but is there any immediate effects?
 
no, i redline my little D15 about 10 times a day. your rev limiter saves it from being over-revved, and the tach is often off by 200rpms or so at the redline (looks like u are at redline, but its actually a little lower). the danger of redlining a stock engine is over-stepping the rpm limits of the ECU's program. mechanically, you are still ok, unless you are running boost (NOS, turbo, supercharger).
 
RPM's = Ruins Peoples Motors. Over Revving is the number one cause of fucked up motors. Don't do it unless you are racing.
 
yes but those are usually modified engines. im talking factory stock. although there is danger of blowing a gasket or seal, but if your oil level isnt over full it should be ok i think.
 
holy shit why would u wanna rev that high i usually shift at 4 or 5 on daily drive. jesus. redlining your car does NOT make you cool!
 
Only if you know what the powerband is. Factory redline is (almost) always well past peak horsepower. You would have to know what the HP and torque curves look like and what your various gear ratio's are to gain any meaningful benefit from overrevving any engine with stock internals.
Short answer: Stock cars with stock engines usually go slower down the track when over-reved.....and needlessly risk engine damage. :eek:
Pappy
 
Originally posted by steelbuster@Dec 3 2003, 07:52 PM
Only if you know what the powerband is. Factory redline is (almost) always well past peak horsepower. You would have to know what the HP and torque curves look like and what your various gear ratio's are to gain any meaningful benefit from overrevving any engine with stock internals.
Short answer: Stock cars with stock engines usually go slower down the track when over-reved.....and needlessly risk engine damage. :eek:
Pappy

yes, the peak hp happens a few hundred rpms before redline, but if you shift much lower than redline, you just happend to get off the vtec cam profile (well, depending of course on when you shift)
 
TOP PART EDITED OUT. I AM AN IDIOT!

read this. this was written by Ed Lansinger (Design Engineer, Ford Motor Company, Visteon Automotive Systems). note the bold print at the bottom.
....

Ed Lansinger wrote about best shift points in a Neon -

I'm going to assume that the DOHC puts out at least 145 horsepower at the redline (7200 RPM). Shifting at the redline in each gear should drag the engine down as follows:



shift RPM drop Horsepower change


- ----- ---------- ------------------


1->2 7200->4700 145->114


2->3 7200->4600 145->110


3->4 7200->5500 145->139


4->5 7200->5000 145->124


(I derived this, but all you really need to do is drive the car, shift, and find out where the motor lands)

Note - and this is important - the transmission does not amplify power.

Power in = power out, minus losses
(which are low for a manual transmission).

This is predicted by the law of conservation of energy.

Is 7200 the correct shift point? It would *not* be the correct shift point if the engine was making more power in the new gear than the old gear. That would mean that you should have shifted earlier. But in this case, the power output at redline is always greater than the power output after the shift. So it's the best performance you can get.

A more rigorous way of doing this is to graph horsepower vs. velocity in each of the gears. If power in one gear drops below the horsepower of the next gear at a particular MPH, then that MPH is where you should shift, otherwise shift at the redline.

above was copied from this webpage:
http://www.allpar.com/eek/hp-vs-torque.html


you = :owned:
 
Very nice.

But yes, when driving hard, and shifting, usually when I go to redline it never drops below 5500 area in my d16z6 but in 2nd it goes to redline even in 2nd because of my mad shifting skills. :p
 
Originally posted by steelbuster@Dec 3 2003, 07:52 PM
Only if you know what the powerband is. Factory redline is (almost) always well past peak horsepower. You would have to know what the HP and torque curves look like and what your various gear ratio's are to gain any meaningful benefit from overrevving any engine with stock internals.
Short answer: Stock cars with stock engines usually go slower down the track when over-reved.....and needlessly risk engine damage. :eek:
Pappy

Hey crxtunerfan..what part of this don't you understand? All the crap you quoted is about a Neon written by someone who we will have to assume knew the power curve and trans ratio's of THAT car....I think that's just what I originally said. <_<
Pappy
 
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