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Discussion Starter #1
I've posted elsewhere the aspirations for my car involving handling and throttle, but my final aspiration for my car is to maximize my revs. Does anyone have 1st or 2nd hand experience with improving the redline potential of a 2002 USDM Ej20? I was thinking maybe new cams, crankshaft, flywheel and clutch, but I am not sure. I am new to the powertrain world of technicals and willing to learn. :D

I was thinking new redline at maybe 8 or 8.5?
 

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A higher redline by itself is meaningless - but I'm sure you knew that. You're going to need a whole different approach in terms of turbo/IC/management/etc. The EJ20 makes pretty sweet power with a larger turbo and supporting mods with its current redline...after that it can be difficult to make more power.
 

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Discussion Starter #3
The higher red line for me, will go hand in hand possibly with a new tranny with shorter gear ratios along with higher power output
 

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and port & polish everything to keep the air flowing...
 

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Doesn't the JDM STi have an 8K redline? Actually in any motor the higher it can rev the more power you can make. Hence the crazy power from F1 engines as 12K rpm. The EJ20 just would really need a proper turbo for it.
 

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Just because certain high-performance engines rev very high, doesn't mean that it is necessarily desirable for all engines to do that. The reason why engines rev high is generally to increase the total amount of air/fuel mixture available to the engine, but EJ20 gets over that by being turbocharged. Once you go that route you apply other limitations, as the relationship between turbo performance and revs is not linear (otherwise power would just keep going up, but it doesn't).
 

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perfusionista said:
Once you go that route you apply other limitations, as the relationship between turbo performance and revs is not linear (otherwise power would just keep going up, but it doesn't).
That is why I said you'd need a proper turbo to accomplish it.
 

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Discussion Starter #10
Different changes to the motor could change for a different rev limit. The general fact of the matter is, maximizing revs is extremely advantageous in the competitive world. Increasing turbo output, displacement and power train, I imagine would put you in the seat for a such an upgrade, more revs that is.
 

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Trainrex said:
This isn't that far off topic, so I'll ask it. What does everyone in hear think redline really is?
Josh,

I would think redline should be at whatever the sweetspot for tourque/rpm where the engine is putting out all it has for the gearing of the tranny/diff,etc.

For instance, I have my rev light set to 6500 and try to stay in that range when Im runnin it up to the ol, spirited driving thingy,
I have found that you dont gain many more MPH runnin in the red..........


But you do get to hear the engine snap,crackle,pop,cry,beg,sht,and feel your booty pinch closed at around 73000revs..... :D

Shotgun
 

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ShotgunTC88 said:
Josh,

I would think redline should be at whatever the sweetspot for tourque/rpm where the engine is putting out all it has for the gearing of the tranny/diff,etc.

For instance, I have my rev light set to 6500 and try to stay in that range when Im runnin it up to the ol, spirited driving thingy,
I have found that you dont gain many more MPH runnin in the red..........


But you do get to hear the engine snap,crackle,pop,cry,beg,sht,and feel your booty pinch closed at around 73000revs..... :D

Shotgun
What you are describing is actually your powerband. Redline is the point where things become unbalanced and unstable and/or the valvetrain can't handle it. Our redline is set at around 7200 rpm because that is the point where our valvetrain stability fades, and valve float comes into play hence eventually throwing a shim and/or bending valves. I'm not up on the JDM lingo, but I know certain JDM heads and valvetrain assys. can handle 8000 rpm. Some cars redline is set because the rotating assy. (bottom end) isn't balanced past that. Some redlines are set because the valvetrain can't handle it, and some both. A typical late 70's small block chevy 350 has a redline of aprox. 5500 rpm. The same motor when balanced, blueprinted, and with the correct valvetrain such as our race engines, can spin up to 8000 - 8500 rpm safely. The power band is then tuned to maximize power up to that redline effectivly through heads, carbs, F.I., and forced induction on some engines such as ours. Normally a car can be over revved past it's redline (missed shift) for a couple seconds, but any prolonged use at that speed (minutes)will result in damage


The moral of the story? Redline is where your engine becomes internally unstable. The higher the redline, the better the engine is balanced, the better the valvetrain, the more potential for making power.
 

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Discussion Starter #13
The moral of the story? Redline is where your engine becomes internally unstable. The higher the redline, the better the engine is balanced, the better the valvetrain, the more potential for making power.
This is exactly the aim I am looking for. However, generally for most Ej20's an increased redline is achieved after new internals. Generally meaning a new motor. The motor that I'm interested in is the still developing Tomei JDM motor. Uses a cool engine set up. Radiator at the classic location, the intercooler placed between the headlights, and the hoodscoop used as a port for direct cold air intake. This is pretty much the WRC car design. As of now they estimate their redline between 9k-10.5k. *drool*
 

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EtherealWRX said:
Radiator at the classic location, the intercooler placed between the headlights, and the hoodscoop used as a port for direct cold air intake. This is pretty much the WRC car design. As of now they estimate their redline between 9k-10.5k. *drool*
Double drool :wiggles:
 

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I believe it has more to do with volumetric efficiency (of which I don't claim to be an expert). But at higher revs, the engine is consuming much more air than our small hairdryer TD04s can produce, leading to low VE. In order to make the fullest use of a faster rotating assembly, you would need a bigger turbo, but then you would have to deal with turbo lag (can't win them all I guess).

-chris
 

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fengshui said:
I believe it has more to do with volumetric efficiency (of which I don't claim to be an expert). But at higher revs, the engine is consuming much more air than our small hairdryer TD04s can produce, leading to low VE. In order to make the fullest use of a faster rotating assembly, you would need a bigger turbo, but then you would have to deal with turbo lag (can't win them all I guess).

-chris
Absolutely. Putting a monster turbo that comes on at 5000 rpm on an engine that redlines at 7200 rpm is pointless. You have 2200 rpms of power. That is a "peaky" powerband. Putting that turbo on a car that redlines at 9k will make it an absolute monster that will have more of a linear powerband and pull for 4000 rpm in each gear.
 

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Discussion Starter #17
Turbo's aren't linear with the powerband which is why when rev limits increase, the necessity for a larger power source is needed. The Turbo Tomei is planning to use, has a semblence to the PE1818.
 

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Discussion Starter #19
Still can't beat my 15 year old 2 gear bicycle with an AK 47 :p
 
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