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How High Can A Stock R33 Rb25De Rev?

TurboDoseBro
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TurboDoseBro Proficient

TurboDoseBro

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As title says, how high can a stock RB25DE rev up to effectively? Being an RB motor i'm expecting the normal 7000RPM to be a 'safe' redline for the internals. Would there even be any point in increasing the redline as the internal components for example camshafts, valves, crank shafts, etc might not support any higher than 7000RPM, and drop the power afterwards instead of increase? As horsepower = (RPM x torque) / 5252, I'm weighing up the benefits of removing the rev/speed limiter.

Many thanks.

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https://www.sau.com.au/forums/topic/359667-how-high-can-a-stock-r33-rb25de-rev/
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G0DZLR Mentor

G0DZLR

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they run out of power after about 6 anyway. unless you had different profile cams and stuff it wouldnt be worth it. my 25DET revs out to 8 but only makes power till 7 really (on its current tune)

Nee-san Grand Master

Nee-san

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What you need is two of the big ones, and you need them by tonight.

No, seriously, if you have an NA the best way to make it quicker without wasting huge sums of non recoverable money (is it ever ?) is hiding a nitrous set up.

TurboDoseBro Proficient

TurboDoseBro

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No point. DE, lol!

That's probably one of the worse replied to this thread lol. Why do NA racecars or any racecar for that matter want to rev higher then?

Yeah seems like no point as power drops before redline anyways. In saying that it would sound awesome with an extra 1k RPM lol.

Edited by TyresBro
Galois Veteran

Galois

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In short, with different cams you can make your big power higher in the rev range (at the sacrifice of lower rpm power).

So racecars with a big redline obviously aren't using the same cams as an average street setup. You are right though, in theory power = torque *rpm, but in reality the engine is incredibly inefficient, and the cams are designed to give a power band at certain revs. The stock cams are not designed to cope with 12k rpm, they just couldn't get the fuel and air in.

89CAL Grand Master

89CAL

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That's probably one of the worse replied to this thread lol. Why do NA racecars or any racecar for that matter want to rev higher then?

Yeah seems like no point as power drops before redline anyways. In saying that it would sound awesome with an extra 1k RPM lol.

they are setup to run like that. Formula 1 cars are designed to rev high and get there quick, why? Because they are the pointy end of motor racing , Your NA skyline.... Is not the same as this

FYI, before the limitations on engine development in F1, they would spend billions doing this...... Hence why they rev hard and make such good power/torque despite being NA V10 3L then V8 2.4L

(Bring back the 1200hp turbo days :), would be amazing)

Galois Veteran

Galois

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Posted

2013 they'll be bringing back the turbo days, but similar hp and 4 cylinders instead (unless various parties manage to change that now-plotted course for f1).

Those old f1 cars used to push out 1500hp for qualifying laps, which is as long as the engine would last lol

TurboDoseBro Proficient

TurboDoseBro

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Yeah it was a rhetorical question to Kinks. My understanding of upgraded cams is that they definitely do push the powerband higher in the rev range (assuming your engine can support it), but because it's higher RPM it = higher power.

Now it would be stupid to compare our engines with that of competition race cars especially F1 (especially a DE). These engines are tuned to be on the edge of it's limits. The point was if we could squeeze an extra few kW out of a higher RPM as it feels as though there are about 500RPM - 1000RPMs of extra power left with intake and exhaust mods.

I think summary = dyno time.

PM-R33 Grand Master

PM-R33

Posted
Posted

Your power will fall off before 7000RPM regardless of bolt on mods on a NA RB25.

If you want a decent increase in power on a RB25DE run nitrous, other wise I wouldn't even bother modding one past an exhaust/intake. Absolute waste of money for the tiny power increases.

89CAL Grand Master

89CAL

Posted
Posted

Yeah it was a rhetorical question to Kinks. My understanding of upgraded cams is that they definitely do push the powerband higher in the rev range (assuming your engine can support it), but because it's higher RPM it = higher power.

Now it would be stupid to compare our engines with that of competition race cars especially F1 (especially a DE). These engines are tuned to be on the edge of it's limits. The point was if we could squeeze an extra few kW out of a higher RPM as it feels as though there are about 500RPM - 1000RPMs of extra power left with intake and exhaust mods.

I think summary = dyno time.

I wasnt comparing, I was stating different design concepts. F1 engine designed to race, RB25 is designed for a street car to have useable power. That is the key thing here. An F1 car doesn't need power at revs it never see's so all the power is at the top where the engine is used the most

RB25 is designed to be drivable everyday that's why it's not built with the intention of having power past redline, it's designed to have enough power to putt around town or smash it to about where the redline is set, compromise basically

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