Anyone go all motor Spec V?

[zspeed10]

It's got a ton of displacement and great internals, anyone got a clue what it would take to get 250 at the wheels, all motor? I'm sure intake and exhaust, computer, cams, valve springs, would it need; ported head, shaved head, thinner metal head gasket, dry sump? Anyone with any info on all motor 2.5 liter please check in!

[zspeed10]

Or more! Heck I'd love to get 300+ all motor. I've seen Nissans racers and I think they run around 250-300 but they're engines are worth 2 of my cars! I'm just looking to go as fast as possible all motor with turbo comparable cash.

[nametakennow]

In hp per dollar terms, turbo is the way to go.

200whp all motor is fairly easy, I/H/E/BSR/cams, but beyond that you're in mostly custom territory. Intake mani and TB spacers are a few more ponies, but that's really the end of it.

You'd have to tear it apart and rebuild everything from scratch to get 250+.

[PacoBJuarez]

what's BSR?

[nametakennow]

Balance Shaft Removal, JWT sells a kit.

Increases vibration a little bit, but unlocks a pretty good number of hp. I don't remember how many off hand.

[PacoBJuarez]

Ok, thanks for the clarification.

What about cams? Does that increase vibration at all?

[nametakennow]

Probably, given that the idle will be a little bit lopey. None of the cam grinds I've seen for the QR are too extreme, so I wouldn't expect much additional vibration.

[NismoB13]

Don't forget the lighter flywheel, pulleys, ECU reflash, and better clutch.

[zspeed10]

So your saying 200 or so is all I could expect without blueprint and the sort? What about some head work? Valves and springs, get 'er up to 7500 rpm? Thanks for all the input guys. I would intend to keep daily drivable so I'm glad to hear about those cam grinds you're familiar with.

[PacoBJuarez]

Don't forget the lighter flywheel, pulleys, ECU reflash, and better clutch.

What's an ECU re-flash?

[nametakennow]

It's a procedure that basically clears the ECU so that it goes through the adjustment period (as when the car is new) again. This allows it to compensate for significant mods more effectively.

7500rpm would be a stretch, and even with cams the powerband will be dry that high anyway. JWT makes a valve spring upgrade that will get you to 7200.

Note, JWT cams often cause a CEL. NISMO cams don't. Unfortunately, the NISMO ones are more expensive.

About 200 is going to be the limit. I'll double check that, maybe someone is making more now.

A lightweight flywheel is going to make it awfully jumpy for daily driving. If there's a midrange flywheel out there - i.e. not one of the super light 10lbs or less ones - then it might be a consideration. However, flywheel upgrades generally lead to CELs because of teeth counts. I'm pretty certain this is the case on the QR25.

[PacoBJuarez]

So when I took my car in for the ECU re-program recall, did that basically serve the same purpose?

[VMPhil]

no, it doesnt. an aftermarket ECU reflash remaps the Programming for more performance. However a the only true reflash that exist for the 02-06 Sentra is the JWT reflash. The other alternatives are the S-AFC and the Technosquare reflash. Now a few people have said that the Technosquare reflash doesnt net you much power but can raise your redline (which isnt a good idea with out cams and Valve springs) a few people have claimed no real gain from the technosquare. The problem is Nissans ECU's are encrypted. The JWT seems to be the only real deal. also from what i have read it is a bad idea to go beyond 6800 Rpm on the QR unless you change the crank (and a few other things) for a shorter stroke.

[VMPhil]

i think the most powerful all motor pre 07 spec i have read about, with dyno sheet, was 197whp

[nametakennow]

Yeah, I went and did some research on this stuff because while I'd heard of reflashes for the QR, I didn't know much about them.

VMPhil hit it on the head.

One other thing Technosquare claims is that Nissan actually programs a buffer on the TPS such that you never actually quite get to wide open when you floor it. They say their reflash takes care of this issue. If that's actually true, which I kind of doubt, then most power gains are simply going to come from having the TB actually open up all the way.

The problem with a reflash is that you have to send your ECU off to have it done, so you're carless for awhile unless you have a spare ECU lying around. That issue, combined with the fact that an SAFC allows you to do the corrections yourself in real time in real driving conditions (preferably with a passenger doing the O2 readings and adjustments), makes the SAFC generally the more attractive option for most people, even if it doesn't quite net as much power.

[NismoB13]

Oh yeah, I forgot about the electronic throttle body thing. It would make things more difficult.

[zspeed10]

Awww!!! 197! ? That kinda blows. I want a linear power curve, so maybe a supercharger? Do I really have to go turbo to get 250? I think of turbo set ups as being finicky and always in need of attention. I wanted all motor as a kind of set/build it and forget it sort of thing. I do alot of mountain driving, you know 2nd and 3rd 3-4000 to redline, in and out of corners , and that kick in high rpms from a turbo..., all that throttle manipulation in the corners, I just don't think a turbo can give me what I want. But I'm here for suggestions guys , so please...

[nametakennow]

I've only seen one supercharged SE-R and it was a completely custom job.

Stick to the turbo. Power stays decently linear with the sort of low boost you'd need to get to 250 given that the QR already has gobs of low end anyway.

[Lazybeef]

I think JET performance has an ECU reflash. Pricy though, they are asking 399 for it.

[fishRich]

Wouldn't mods like these just tear the transmission in pieces? When you double the HP, doesn't that put the rest of the drivetrain in jeopardy? Just curious.

[nametakennow]

No. The stock transmissions on most cars are much beefier than you might expect. A clutch upgrade is all that's required to get up past 300hp, though I'm sure the limit of other parts (axles would be my next bet) isn't too far beyond there. This is true for both the SR and the QR. I know there are QG's with ~200whp, possibly more, (turbocharged) using stock transmissions as well.

Stock clutches are toast beyond 200whp, generally, though mine survived ~1000 miles at 220 or so and still doesn't slip at all back at stockish power levels even with 62,000 miles on it.

[Buzzman]

So your saying 200 or so is all I could expect without blueprint and the sort? What about some head work? Valves and springs, get 'er up to 7500 rpm? Thanks for all the input guys. I would intend to keep daily drivable so I'm glad to hear about those cam grinds you're familiar with.

I read a while back that this engine is not designed to produce high revs. The main reason for that is the bore/stroke ratio. This engine has a fairly long stroke, which results in fairly long piston travel. What that means is that at higher RPM's the pistons are traveling faster than most 4 bangers. What I read was that in this engine, at 6,500 RPM, the piston speed is equivalent to most engines running at 8,000. It's something to consider when trying to get those high revs.

[VMPhil]

ding ding ding

thats correct.The only way to do a high revving QR is to do a complete custom job like Travis's SQR23, which IIRC is a QR block with a SR20 Crank and after market cams and valve springs. revs to like 8.5k.

[nametakennow]

I think I saw his tach hit 9 something in one of the vids of that thing. I want to say he's running a whole bunch of boost too. That car is ridiculous.