complete engine overhaul questions.

Skeeterbop

I've been wanting to do something similar to the OP, except I'm not shooting for a HP goal. I plan on staying NA and trying to make the engine as responsive as possible while also being able to safely bump the RPMs to 8500-9000. I think with a lot of time, trial and error, and money. 500whp is doable. I think you would need to ditch the VVEL and go to a traditional intake cam though. And obviously a Standalone EMS. I also think it would require race gas to reach that number as well.

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theDreamer

There was a 350z in Japan (limited run) that revved to above 8k but they dropped the displacement from 3.5 to 3.3. It was designed to alter the powerband for track setups.

Now onto the OP, you must remove the ideas from American V8 motors when dealing with the JDM engines. The Japanese prefer smaller displacement cars which rev higher and occasionally throw turbo(s) on. Now this is great for certain things, but NA power it is very limited and even with engine upgrades you are very restricted. Also, this motor is very 'tech' oriented which is also a negative as just throwing upgrades at the motor will not directly lead to results.

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wstar

JeffBlue's number is about right in that 330rwhp is the best reasonable number you could hope for with NA, full bolt-ons, and a very high-reading happy dyno on a really cold day. Assuming you could easily bump the car from a 3.7 to a 4.5, a rough horribly inaccurate estimate would be about 425rwhp (330 * (4.5/3.7)). That's assuming you can get VVEL to play nice with you, but so far it seems to be mostly self-adapting within that sort of power range, given appropriate UpRev tune with a decent timing starting point and fueling. I like the idea of doing that, but I really don't expect it to be cheap or easy on this car unfortunately. It would be simpler and cheaper to slap on an SC setup and just use pulley size and ECU tuning to pick your sweet spot anywhere between around 350-500-ish rwhp.

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chii370

Wstar, your the first person in a long time that has mentioned SC on this car. From what I have heard and read over and over on forums, people are getting screwed going the SC route, not even receiving the SC factory claim of horsepower gains "which isn't even close to TT" let alone a respectable whp number in the 500-550 range which I would EXPECT with a $7000 investment.

I wouldn't have minded going SC, no lag, and it just feels like a stupid sounding NA engine with more power which is all fine and great. But did they figure out the problems yet? I've heard quite a few stories so far about how people bought one from stillin or gtm and only saw gains of 125-150 FWHP. IMO 125 whp isn't worth 7 grand just on the forced induction side of things, because now you have spent a lot of money and done NOTHING to your stock motor to ready it for that. Instead why not spend the money on the motor itself.

I'm starting to understand a little more about the differences in these cars with more research and Talkin to you guys. VVEL is what it is, I think its limited by design, that problem aside though there are a LOT of things on the motor that can be improved, and I understand it took years and millions from Nissan to develope it..... But there's one crucial thing your missing. THEY WEREN'T BUILDING A RACE CAR!! They have to get the most power they can AND worry about maximum reliability, fuel economy, emissions, engine life, transmission and differential limits... I mean the list goes on and on.

To say it's at it's max NA HP rating is naive, it is for what they were trying to design yes. But I understand what you were getting at. Ok so let's assume you can't get 500 out of it, but as it sits right now mines 368 at the crank so 450 crank seem unreasonable? I just think the main problem with this entire subject is that no one has tryed it yet, to expensive, not enough parts, and untreated territory.

Everyone I've ever talked to has always just TT, SC, or put on an exhaust with headers "3 in" and slapped in a cold air with k&n filters. That seems to be the average extent of experimentation and knowledge am I wrong? But even the guys with the exhaust, headers, intake, tune, filters are seeing 40+ gains crank depending what Dino u use. Hell I've done one thing to mine, I put k&n panel filters in and it made a average powerband gain of 4.5 horse with a max of 11.5 at 6krpm.

What does that tell me? This engine has a lot of room to grow on the intake side of things, as it sits from the factory it's struggling to breathe. So a bigger intake manifold "perhaps one from the gtr" huge heads, bigger injectors, and a tune that makes it work and I bet you could match or BETTER the gains from all your boltons and then you can still bolt on all that stuff after for even MORE gains. Little things here and there help too. Light weight flywheel, forged aluminum heads "saves weight" forged aluminum pistons.... I mean it starts to add up pretty fast and they are always gains. By pretty conservative calculations for average projected gains on each part the engine dips in the 450 crank area with relative ease..... And this is without considering an increase of volume to 4.5 or whatever you choose.... Which yet again will have decent gains by itself. Hell that was already backed up in theory by the 300zx vs 370z full bolt on base HP compairison. not all, but a lot of that extra power can be contributed by the increase in displacement IMO probably most of it.

wstar

I don't know where you're getting that SC's are in issue on this car. There have been plenty of solid SC installs on it, and GTM can set you up with a 500rwhp SC if you ask them to. You don't get to the same peak HP numbers as easily as a TT setup, but IMHO the power is more usable in a practical sense, and the whole setup's a bit less tricky and overcomplicated. I'd recommend the GTM over the Stillen. There are a number of solid Stillen installs out there, but IMHO it just seems like the satisfaction rate has been higher with GTM's kits in the big picture.

On the 3.7 NA side, I don't think it's struggling to breath as much as you think. There are just practical limits to how much volume you can push through this engine. The Stillen Gen3's seem like plenty of intake for the engine. Combine them with a solid exhaust setup (the practical pinnacle being FI's long-tube headers + catback) and a good dyno tune and you're getting about all you're going to get out of this engine with just bolt-ons. A whole lot of personal experimentation has been done on this engine in stock 3.7 NA form with bolt-ons over the past 3 years by a lot of smart mfgs and home DIY-ers.

It would be surprising if anyone found further significant gains in this area at this point without boring/stroking the block. Once you do that you've got a whole new engine of course, and you might need to play with the heads too, but then you run into the practical problem of whether or not you can do it in a way that's VVEL-compatible, since nobody's had much luck yet actually programmatically altering VVEL's workings with an ECU tuner. By the time you sort out this 4.5L setup it's just going to cost you a lot more than the proven SC/TT routes.

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