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Discussion Starter · #1 ·
I don't know if this is true or not, but I heard a rumor on some other forum, while searching on some nissan parts about bumping the redline on the QR25 to 7200RPM, I've been trying to find some more information on it ANYWHERE, but I've been coming up dry. I'm still trying to find the first page that I found this rumor, but I'm not getting anything solid.

Does anyone know if this is achievable? How is it accomplished and how would the extra rpms react with the short gear tranny or is the tranny capable of just working with the extra rev and giving extra speed?

Sorry if this is a false alarm, not trying to get any flames started, I'm just curious if it's possible to move the redline and how much is possible.
 

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Eganrac said:
I don't know if this is true or not, but I heard a rumor on some other forum, while searching on some nissan parts about bumping the redline on the QR25 to 7200RPM, I've been trying to find some more information on it ANYWHERE, but I've been coming up dry. I'm still trying to find the first page that I found this rumor, but I'm not getting anything solid.

Does anyone know if this is achievable? How is it accomplished and how would the extra rpms react with the short gear tranny or is the tranny capable of just working with the extra rev and giving extra speed?

Sorry if this is a false alarm, not trying to get any flames started, I'm just curious if it's possible to move the redline and how much is possible.
To do that you need to reprogram the ECU. I don't think anyone has cracked the ECU yet, however.
 

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It isn't possible on the QR without cams, springs, rods, and a few other parts. The engine would literally fall apart with all of the stock internals.
 

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silverbullet said:
OK, So when you do have the internals, how do you change the rev limiter!!!!
wait for someone to crack the code on the ECU. I'd say that JWT is already working on it.
 

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A few companies have just started making high compression pistons and rods for our cars. Supposedly JE makes pistons and Eagle makes rods...this is new. You would also need aggressive cams in order to get good top end power.

Theoretically, you could also destroke the QR, run JDM high quality internals and push the motor to upwards of 10K RPM...that's what people say, but now is that really worth it? ;)
 

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Discussion Starter · #8 ·
I'll let you answer that last question.... Is it worth some guy pulling up to you in a Mustang, scowling at you with his gas-guzzling V8 only to be smoked by a demon of a 4cyl, pulling up next to you at the next light, looking confused as ****, wondering what just happened?

Yes... Yes I do believe it is worth it.... if I was rich :p

But seriously, I'm curious about pulling some power out of this car. I've been pretty disappointed with the numbers that I've been seeing in terms of power. The highest I've seen is 275hp, for a civic, this might be impressive at 1.6liters on a daily driver. But on a 2.5liter, not a daily driver, I find this to be a lil odd. Although, I have to say, even at such lower numbers. I've been hearing some WICKED stories about the performance on these cars. Even one I read about a B15 with less HP than this, beating out an NSX that was highly modded. That story was in an SCC mag, that I left at my friend's house. I don't remember what month it was. But that was the thing that made me look at the sentra in a whole new light. Performance is great... But bragging about numbers is fun ;) And if the car breaks 300hp, without issues, I'd be ecstatic.

/rambling OFF
 

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Eganrac said:
I'll let you answer that last question.... Is it worth some guy pulling up to you in a Mustang, scowling at you with his gas-guzzling V8 only to be smoked by a demon of a 4cyl, pulling up next to you at the next light, looking confused as ****, wondering what just happened?

Yes... Yes I do believe it is worth it.... if I was rich :p

But seriously, I'm curious about pulling some power out of this car. I've been pretty disappointed with the numbers that I've been seeing in terms of power. The highest I've seen is 275hp, for a civic, this might be impressive at 1.6liters on a daily driver. But on a 2.5liter, not a daily driver, I find this to be a lil odd. Although, I have to say, even at such lower numbers. I've been hearing some WICKED stories about the performance on these cars. Even one I read about a B15 with less HP than this, beating out an NSX that was highly modded. That story was in an SCC mag, that I left at my friend's house. I don't remember what month it was. But that was the thing that made me look at the sentra in a whole new light. Performance is great... But bragging about numbers is fun ;) And if the car breaks 300hp, without issues, I'd be ecstatic.

/rambling OFF

275 WHP on our car will run it in the high 12s...that will decimate a Mustang GT and give a Cobra hell. With lighter wheels and slicks, a few other mods and good weight reduction, that 275 WHP could land low 12s or high 11s...no one has gone this far, yet. Honestly, I have put a few grand into my car and it will give quite a few sports sedans a run for their money. With the tranny build, nitrous and lighter wheels, I hope to see 13s. Personally I'll be happy with that but if you love your car and want to push crazy custom power, by all means do it. It is a matter of your income vs. your threshold for how much you want to spend.
 

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Eganrac said:
I'll let you answer that last question.... Is it worth some guy pulling up to you in a Mustang, scowling at you with his gas-guzzling V8 only to be smoked by a demon of a 4cyl, pulling up next to you at the next light, looking confused as ****, wondering what just happened?

Yes... Yes I do believe it is worth it.... if I was rich :p

But seriously, I'm curious about pulling some power out of this car. I've been pretty disappointed with the numbers that I've been seeing in terms of power. The highest I've seen is 275hp, for a civic, this might be impressive at 1.6liters on a daily driver. But on a 2.5liter, not a daily driver, I find this to be a lil odd. Although, I have to say, even at such lower numbers. I've been hearing some WICKED stories about the performance on these cars. Even one I read about a B15 with less HP than this, beating out an NSX that was highly modded. That story was in an SCC mag, that I left at my friend's house. I don't remember what month it was. But that was the thing that made me look at the sentra in a whole new light. Performance is great... But bragging about numbers is fun ;) And if the car breaks 300hp, without issues, I'd be ecstatic.

/rambling OFF

If the article you mention is the one I'm thinking of (it was at Buttonwillow for the track attack or time attack) the car that passed the NSX was an older (B13) SE-R cup car SRX class and it had a turbo 2.0L
Found a link:http://search.netscape.com/ns/boomf...remove_url=http://www.sportcompactcarweb.com/
the car:
 

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the biggest thing you guys aren't thinking about is the crankshaft!

between 7200-7400rpm the crank will crack and eat itself alive. Destroking with a custom forged crank would be the only way to go.

that requires money. And if you're going for n/a of that caliber, a standalone ecu is what you should be looking at.

What you new guys need to realize is, if you raise the rev limiter without cams, there's no more power to be made. Stock cams aren't made for higher redline than stock....and there are specific reasons the QR isn't a rev-machine like hondas. The QR is an undersquare motor, meaning the stroke is larger than the bore. Which is one of the reasons the torque is so good, and another reason why high rpm isn't really feasible.

It's a truck motor, basically.
 

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well, overseas and in South America/Latin America, the Xtrail has been utilizing the QR25 since 2002 if I remember correctly.
 

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chimmike said:
well, overseas and in South America/Latin America, the Xtrail has been utilizing the QR25 since 2002 if I remember correctly.
Yes, as well as Canada. And the QR in those engines seem to be less problem prone for some reason.
 

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because they're used for basically what the engine was intended to do ;)
 

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NickZac said:
Yes, as well as Canada. And the QR in those engines seem to be less problem prone for some reason.

Perhaps because the QR25 in our X-trail is only rated at 165 HP?

Another interesting fact: one member on X-trail section "Terranismo" claims that his truck "in 4th gear will go to 6700 RPM"
see post #14 in this thread: http://www.nissanforums.com/showthread.php?t=91349
 

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it won't exceed the stock rev limiter.....i'm sorry to say that the stock tachometer is not that accurate.
 

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Sorry for bumping an old thread but I just wanted to add to this discussion about the rev limiter on the QR25DE...

We have been having discussions in the X-Trail forum following my BSR mod and its has been confirmed that some generation X-Trail in some countries (where the X-Trail is advertised with 180 HP stock rather than 165 HP) does have its redline and fuel cut off at 6700 rpm rather than 6200 rpm. Probably one more good reason to get rid of the bs unit.

linky
 
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