QR25DE

[sykikchimp]

Since Nissan is going with this use the same engine in every other car..  Lets say for a minute that the QR25DE from the Spec-V will end up in the S-chassis predessesor (mini-G45).  How do you think it will be as a tunable engine?

We all know how happppy the KA, and SR are turbo'd.  How do you think the QR will stand up?  From what I gather it has the makings of a true monster.  The questions I have in my head are:

What effect would Variable Intake runners have on a turbo Engine?
How hard or necessary is it to defeat the VTC for high PSI applications?
How would the Balancing unit on the bottom of the timing chain effect performance?

Here are the specs:

Engine Code: QR25DE
Type: Inline four, aluminum block and head
Valvetrain: DOHC, four valves per cylinder,
VTC variable intake cam timing
Displacement: 2488cc
Bore x Stroke: 89.0mm x 100.0mm
Compression Ratio: 9.5:1
Claimed Crank Hp: 175 hp @ 6000 rpm
Claimed Crank Torque: 180 lb-ft @ 4400 rpm
Measured Wheel Hp: 141 hp @ 5750 rpm
Measured Wheel Torque: 150 [email protected] 3750 rpm
Redline: 6200 rpm

Things I wonder about not in that list:

Cam duration and Lift?  Composition of metals used to build the Rods? pistons? Crank?  How Strong are the Valve Springs?

So essentialy..     KA/SR vs. QR  ?

[AceInHole]

the QR25DE is a lot like the bastard child of a KA24DE and an SR20DE... so i'd imagine that it'd respond to boost just as well.

Oh yeah... and we're waiting for the mini G35, not the G45 <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/tounge.gif" border="0" valign="absmiddle" alt=':p'>

[s15dude]

I doubt it will happen but we should all pray for a QR25DET. It could happen but prolly won't.

[Ser_rah]

On thing; QR engine has an open-deck block design. &nbsp;This is a feature more traditionally associated with Honduh's.

The closed-deck engine block is what makes the SR so good to push air through. &nbsp;So the QR might not be as tolerant of boost. &nbsp; &nbsp; &nbsp;I'm not sure about the Ka but I think it's a clck design too.

&nbsp; Doesn't mean the QR can't take pressure. &nbsp;I'd bet you have to fortify the block to get it to hold more than like 5-7 psi.

[sykikchimp]

I've only worked on my KA-E and DE so I don't know what an open deck design is. &nbsp;Can you explain the difference?

[SimpleS14]

I'm wondering the same thing since I don't know the difference.

[ca18guy]

In the pic below notice the space between the piston wall and the block, thats an open deck design. &nbsp;A regular block does'nt have that (obviously)
http://www.honda-s2000.de/01fahrzeug/images/engine_open_rt_460.jpg

[onebadm5]

i've been talking to the B15 guys for months, and after test driving the SE-R Spec V, i have to agree that the QR is not half what it is cracked up to be. plus as Ser-rah said, many of them are worried that the block will be up to the task of taking moderate boost pressures.

[Ser_rah]

I also heard (I forgot where sorry) that the QR has really soft valve springs, thus the low redline. A nice JWT cam package with ecu, springs, and retainers should be an expensive, but worthwhile fix. This means shit to the 240 driver though.
I am not sure but... You would also have issues with Tranny/bell housing if you tried to put a QR under a 240 hood.
I am suspending judgment on the QR until I see the aftermarket packages for it, although the block design, and soft valve springs do concern me.

[sykikchimp]

whats the space for?<img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/confused.gif" border="0" valign="absmiddle" alt='???'> &nbsp;Ser-rah its of concern to the 240 crowd if they build a 250vx (orsomething) and use the QR. &nbsp;Thats why I'm wondering. &nbsp;I want to see how Area 51's supercharger tums out...