Destroked QR25DE..










Here's the details..

SR20DET crankshaft (86mm stroke, down from the QR's 100mm stroke)
6" Custom Cunningham rods
Custom 92mm 8.8:1 CP pistons (moly/ceramic coatings)
Custom 272* 11.2mm lift cams
Custom valvesprings/retainers
Custom flywheel (uses Maxima/Z clutch and works with stock QR trans)
FI-R ported head
Custom head and main studs
LA Sleeve T-sleeves (AEBS)
Stock MLS head gasket

Electromotive TEC III-R
1000cc injectors
Precision SC61/T350 (.63/.60 A/R's)
FI-R custom 4-1 316L Stainless turbo manifold
HKS 50mm wastegate
FI-R custom short runner intake manifold
FI-R custom fuel rail
Greddy Type R BOV
FI-R custom intercooler (Griffin core, using custom end tanks)
FI-R custom piping
FI-R custom 3" DP and 3.5" custom exhaust
Apexi 3.5" muffler
KA24DE throttle body
Twin Walbro 255lph in-tank pumps
Twin feed fuel system
Aeromotive FPR, modified for twin feed
Autometer boost, EGT, water temp, oil pressure guage
Greddy Profec E01 boost controller
Custom guage cluster
AEM UEGO Wideband


What we've done... is taken the SR20 crankshaft, which shares the same bore centers... and modified it to fit in the QR block. The main pin diameter is the same, which made it easy. The thrust area had to be modified, as well as the snout for the QR timing gear and oil pump drive collar. The rear main seal fit perfectly.. and a custom flywheel was made to get the right spacing/bolt pattern to use the stock trans. I'm running a 250mm clutch with a 1200kg pressure plate. Drives almost like stock, and holds 450ft lbs. With a rod/stroke ratio of around 1.76:1, the bottom end can now take better advantage of the QR's awesome flowing cylinder head. It's only a few ticks under a K series head.. flow wise. The simple cam on bucket valvetrain allows for high revs with no breakage. So far, we've made 400whp at 13psi on pump gas.. with a 11:1 A/F and only 20* total advance. This was with a massive boost leak as well.. the 1/8" NPT plug in the compressor housing wasn't installed. DOH! We'll be heading back to the dyno on the 25th of this month to see what she'll do. I'm thinking around 500whp on pump gas at 15-16psi, and 600-625whp at 25-30psi on C16.


Here's the initial fire-up video.. it was kinda rough at first because all of the assembly oil/lube had to burn off.. but, it settles down to a nasty lope at idle.

http://www.fi-r.net/images2/CharlesCarFireUp.wmv

Anyway.. thought you guys would appreciate this engine.. Nissan 4 bangers aren't known for being able to rev too high..

Travis

 

Here's a few engine internal shots..






I'm also doing a nasty N/A build soon.. Hoping to compete with the K-series 2 liter guys..

Travis

 

nissan doesnt' fu;ck around on bottom ends. that crank looks good enough to eat

 

yeah looks great dude

how does the 100mm crank do in NA motors?? i would imagine with the right hardware and good balancing you could get about 8k rpm out of it, no?? the motor is 92mm bore stock?? isnt that like a 2.6l, not 2.5?

sry for all the questions, nice car

 

The 100mm stroke and 143mm rod makes for a torquey engine, but no top end at all. Only plus, is that with a turbo kit, at 7psi on pump gas (T3/T04B S-trim/stage II turbine), it makes 280-285whp/260-265wtq, with a TQ curve that's flat as a rock from 2800-6200. I've taken a 100mm crank to 7200rpm, but there's a nasty harmonics issue past that. I suppose with balancing and such, 8K could be possible. Piston speeds would be approaching 30mps though..

Travis

 

yeah that piston speed is insane....but i figured torque would be pretty sick with that stroke....

good luck with the motor

 

thats bad ***, post up some dynos when done

 

Anything done to make the tranny stronger to handle the power?

 

that thing is badass, lets see some videos!!

 

that's bad as hell. good to see that it can actually rev past 6.5k now. 100mm stroke is mighty large.

 

I thought the Qr25de had a 1.63:1 rod stroke ratio stock?


Modified by MidShipCivic at 12:40 PM 2/14/2006

 

That's how you do a nissan, top mount and all.

what about the tranny setup?

 

There was a misprint in SCC Mag by Dave Coleman, years ago... saying that the QR had a 163mm rod. It was an error.. in fact, the QR has a 143mm rod.. giving us the dreaded 1.43:1 R/S ratio.

The trans, believe it or not.. is very beefy in stock form. The trans is borrowed from the 6spd Maxima, and is huge, to incorporate the VQ35's big power. We've put 500+whp through one, and haven't had a single failure yet. The axles.. are about 1.5" in diameter! Plus, it comes stock with a Helical LSD.. The input shaft is the same size as a Twin Turbo Z..

Travis

 

Nice work!

I love seeing people doing something different.

Sounds like you had a good startup. It's always exciting to start an engine for the first time and actually have it work.

Approximately how much would it cost to build an engine like this? Just in parts? I'd like to hear cost wise how it compares to a similarly built Honda engine.

 

He's got around 7K in the engine... and about 7-8K in all of the other components. This includes my labor to blueprint/assemble and install everything. So, roughly 14-15K for a custom built 600whp car. Probably a little more than you guys are used to spending.. but, keep in mind that almost everything had to be custom made for this setup. Hell, the Cunningham rods were almost 1000.00 alone.. lol..

Travis

 

What year of Sentra is this in? Pretty badass!

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by boosted92 &raquo;</TD></TR><TR><TD CLASS="quote">What year of Sentra is this in? Pretty badass!</TD></TR></TABLE>

Looks like my girlfriends car, so maybe a 2003+. Neat build.

liam

 

^ That body.

 

awesome build. must be a blast to drive.

keep us updated as far as the dyno/track times.

 

Sweet!!! yall finally finish the sickest QR in the world...

 

We head to the dyno on the 25th of this month..