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4000 RPMs = magic?
Posted: Sat Apr 12, 2003 2:50 am
by IggDawg
Maybe it's just me, but my engine seems to have a huge power step at 4000 RPMs. It's like I have VTEC or some crap. what up with that shiznit? 4000 doesn't seem to be around any of the power/torque/boost peaks. so what's up with the sudden surge at 4K? am I the only one with this?
Posted: Sat Apr 12, 2003 4:18 am
by entirelyturbo
Not sure where a turbo's torque peak is, but us N/A guys have ours at 4400rpm. So at 4000rpm for me, my car will leave some "torquey" domestics behind...
Plus, a turbo's power delivery isn't linear like a supercharger. Igg, I would say your turbo is delivering the most efficient boost at 4000 or above, remember what WRX owners whine about all the time, that their cars are dogs under 3000rpm...
Posted: Sat Apr 12, 2003 3:18 pm
by STi_GUY
I have a N/A and my car spikes in power right above 3700. Like you said, feels like Vtec or even better.... AVCS
.
Posted: Mon Apr 28, 2003 1:30 am
by mattocs
When it has specs for max HP and such it says like 135hp @ 6000 RPMs...so when you get the RPMs up is when you get the most power. I notice that above 3000RPM is when I get most of my power.
Posted: Mon Apr 28, 2003 3:23 am
by morgie
Igg : not sure if it's at 4000rpm too, but around that RPM, in full throttle in first, i get that kinda Kick, or "Vtec Like" feeling you describe...
kinda strange.
Posted: Mon Apr 28, 2003 3:45 am
by IggDawg
yeah, it's somewhere in the 3800-4200 range. definitely in 1st gear. I think in others as well. even at part throttle it seems to have a little more pep if the revs creep up to that point.
I thought it was a resonant "sweet spot" in the intake or something. like that's when all the engine's "acoustic" charecteristics fit togehter just right. but even after I intercooled it, that magic spot was still there. The intercooler certainly changed the dynamics of where the engien got the most pull. still that magic 4000-ish mark remained.
Posted: Mon Apr 28, 2003 1:44 pm
by Legacy777
Even the n/a subies have that sweet spot.
It's most likely how the cam profile/timing is setup that makes it act that way.
Posted: Mon Apr 28, 2003 3:46 pm
by STi_GUY
I can attest to that. I love it.
Posted: Mon Apr 28, 2003 7:35 pm
by ciper
Those of you getting the 4k "boost" have an automatic as well?
Posted: Mon Apr 28, 2003 9:16 pm
by morgie
5speed manual for me
Posted: Mon Apr 28, 2003 9:38 pm
by STi_GUY
Same here.
Posted: Tue Apr 29, 2003 1:51 am
by Legacy777
auto
Posted: Tue Apr 29, 2003 4:24 am
by Brat4by4
On the EA-81 in my '85 Subaru Brat it has that same sweet spot at 4000 rpm. It's kinda funny when I realized that that is the same thing I experienced. It feels like a turbo hitting... with the force of a bumble bee, but hitting none the less (70+ horse).
In my EJ22T, I have to say the sweet spot starts around 3000 rpm when cruising. If in a race, yeah the higher the revs the better, but mine will start to really pull at 3000 for nice effortless acceleration.
I HEAR THAT
Posted: Wed Apr 30, 2003 3:30 pm
by Rbees
I know for a fact mine gets a pure boost of power cause i was racin this one guy and he had me until i got my boost and after that i had just enough to beat him it was sweet......Thats subaru for you always something good comes from under the hood even if it would appear as if nothing was there.....I know for a fact there is!!