Spec V, first build, about $1000
08-04-2007, 11:59 AM
#194
0.5 BAR
Thread Starter
Join Date: Dec 2006
Posts: 141
Re: Spec V, first build, about $1000
Originally Posted by klyph
You're a ****** for worrying about your warranty.
How's that JD?
How's that JD?
I'm planning out a build too. It's not a mini me or LS Vtec hybrid type ----, but it's the best we've got for this motor. The QR25 motor was slightly redesigned for 2007.... but the QR in the 2007 Spec V got special treatment. The rods are reinforced, new cam profiles, fully counterballanced crank shaft, improved cylinder head. My parts guy at Nissan ordered in one of the new rods so I could spec it out and take some pics. It hasn't been done before so I can't go to hondahybridbuildspecs.com and download specs so it's in the "paper build" stages right now, so far it looks great. The specs at the critical areas are the same as the old rod the main diffrences are in the profile and construction. The old half ballanced crank has stability issures above 7000rpms but the new fully ballanced motor has a factory redline of 7K meaning theres is probably a good 500-1000 more that can be had safely.
Pics of old rod next to new rod:
All I want is 400-450whp (if I stick with the new factory rod, 500+ with an aftermarket rod) and 7500rpms, that'll put the end of fourth at 125ish MPH instead of 100mph, and a therotecial top speed of about 200 mph
08-05-2007, 12:38 AM
#198
0.5 BAR
Thread Starter
Join Date: Dec 2006
Posts: 141
Re: Spec V, first build, about $1000
it's up in the air, but the only way I'd go w/ a CR that high is a standalone..... I think some where between 9-10:1 is going to be the best especially if I can tune the cam timing. Being able to play with cam timing (cvvt) is great because static CR is a mathmatical theory, dynamic CR is what determines actual power and cylinder pressures, and the majority of that is found in cam timing.
It might be that playing with cam timing I can make 8.5:1 act like 10:1 out of boost and phase the cams in boost to allow more boost with a higher static CR and not sacrifice out of boost performance. Don't know yet
It might be that playing with cam timing I can make 8.5:1 act like 10:1 out of boost and phase the cams in boost to allow more boost with a higher static CR and not sacrifice out of boost performance. Don't know yet
08-05-2007, 04:16 AM
#200
1.5 BAR
Join Date: Jul 2007
Posts: 752
Re: Spec V, first build, about $1000
Originally Posted by Big J
it's up in the air, but the only way I'd go w/ a CR that high is a standalone..... I think some where between 9-10:1 is going to be the best especially if I can tune the cam timing. Being able to play with cam timing (cvvt) is great because static CR is a mathmatical theory, dynamic CR is what determines actual power and cylinder pressures, and the majority of that is found in cam timing.
It might be that playing with cam timing I can make 8.5:1 act like 10:1 out of boost and phase the cams in boost to allow more boost with a higher static CR and not sacrifice out of boost performance. Don't know yet
It might be that playing with cam timing I can make 8.5:1 act like 10:1 out of boost and phase the cams in boost to allow more boost with a higher static CR and not sacrifice out of boost performance. Don't know yet
i dont like this "looks like" analogy at all really.
as for dynamic compression ratio being related to hp, is my definition of dynamic compression ratio fucked, or does it not include the effective altitude that the engine happens to be operating at? (ie, boost doesnt count) boost just adds overall chamber pressure throughout the cylce, and comes in (in less good setups) preheated to therefore need a lower compression ratio. if it comes in dead cold, it isnt that much worse than having half as much...
end rant. (without signing fred ;-) )
