NA Build Options?

[riu]

About a year ago some guy at some car meet told me he wanted to swap a VH45 out of a Q45 into his Z32. I thought thats pretty damn cool and pretty damn crazy. My best friend's father had a Q45 so I asked him about the motor and he told me it was derived from Nissan's Indy motor. So after seeing Slim's Z32 and hearing about Albert's (zGringo) Z32 VH45 project. And the godliness of this motor, I decided I too wanted to do this.

Following the footsteps of John Dixon, I'm really wanting to do an NA build VH45 into my Z32. No offense to boost addicts out there, I just prefer linear NA power over boost.

My goal is to reach around 500 or so rwhp, and I definately wouldn't mind higher.

Now since most of you on here are all about boost, I've had a little trouble finding what would be the ideal way to build a NA VH. John Dixon's route would be rather hard for me to follow since its pretty much all completely custom done, and as much as I'd love to bore a VH to 5.1 liters, I want to see what is possible without going that route first.So this is what I have in mind so far.

Escort Racing Cast Hi-Comp PistonsMore Aggressive Regrind of cams, unless some one can point me to where i can find Aggressive VH cams for sale.Stiffer Valve springsmodified Suzuki Hayabusa thottle bodies for ITBI'm hearing great things about the stock exhaust headers, so unless someone knows some good aftermarket headers i think i'll just have to stay stock.Z32 MT transmission with adaptor plate and custom flywheel to fit (or just a spacer with some Z32 aftermarket flywheel)Map stock ECU with a romulatorPossibly 550cc injectors if i have to.

Would this be a viable tuning route?Are there flaws or things missing here?How much power would this put down?Would this be worth doing or should I just give in and twin turbo it for likely less money and effort and get the same if not better power results?

Thanks
Modified by riu at 4:16 AM 9/4/2006

[John Dixon]

You're going to struggle to get 500rwhp on an NA build without running massive revs, particulaly on stock capacity.You'll need big cams to do it which really means changing the manifolds as the stockers are the wrong length completely. With mild cams it doesn't make a huge difference, with wild ones it does. Also, MAF based ECU is not going to work very well with big camsTo be honest I'd just build it up like you said and see what power you get, 500RWHP really is a lot and if you want the Z32 as a driving tool rather than a muscle car you don't need it anyway, spend the extra cash on the suspension and a good diff.I can supply exhaust manifolds and intake runners / trumpets and air boxes if you want.You will get more power with turbos but IMO the scarifice just isn't worth it.

[slownslurious]

how are you planning on doing the suzuki ITB's AND the JWT pop charger? and in the abscene of a mafs, what are you planning on doing for engine management? I don't think a romulator will support a MAP but I don't know too much about them yet, thats just what I was told.

[riu]

John, the power figure is optimistic, but i would definately want to reach it. I could settle for mid 400 hp range though, but it just feels like a lot of work to only gain 100-150 hp

I've already got a decent suspension set up on my Z32 already, but it could definately be better. Currently i'm running Tein SS coilovers and plan on getting a rear strut bar in a month or two. I plan on having ALL suspension work done with maybe the exception of a cage, before the VH goes in.

Is there a specific differential you recommend? I'm using my stock NA Z32 diff right now, i know its weaker than the TT but its still pretty strong as I understand it. What diff are you using on your VH Z32?

If you were doing this build... which you are... but if you were doing this build with my grocery list of parts i want to throw in there, what would you do different? Just the intake runners, exhaust manifold, different ecu? perhaps motec? If i really want the power should i just go your route and bore it to 5 litres?

Slow,Most of my research and plans have really been a variation of what John is already doing. I had wanted to do ITB and heard that John was doing them, so thats what i'm pretty much going to do. The JWT Pop, i'm pretty sure JWT makes a pop charger for the VH45, i just gotta get it to fit in there, most likely it'll sit where the Z32 intake sits, under the nose panel. As far as ECU, i'm just hearing the stock ECU is so damn powerful that with a romulator you have incredible flexibility with it. If i have to use something different then i will, its not something i've researched a lot yet.

thanks for the replies, this is really helping. I can't wait until i finalize the game plan and start the build

[Mettler]

Romulator isn't a replacement computer. It's a tool that you use temporarily, it pretends to be your eeprom while plugged into the ECU mainboard, and you can use it to change settings while you tune the motor on a dyno or something. Once you've finished, you save a copy of the resultant bin file, burn it to a chip, and install the chip into the ECU... putting the romulator away for use another day.

I don't think the factory comp can take a map sensor.

[defrag010]

I've seen people in the DSM ecu community edit the MAF table values in the ECU to MAP sensor values so they can run a calibrated map sensor instead of the maf sensor with no changes to the stock ECU.

[slownslurious]

I've never heard of that being done in the nissan community... the problem is that mafs is voltage=airflow whereas map=air pressure and the two curves are different, so where the ECU is looking for a certain baseline of information the map is measuring a different parameter.If you can do it on the stock ECU that would be really cool, but I think you would be pioneering that technqiue yourself...

[John Dixon]

MAP on nissan ECU is in the pipeline ...Problem is I think that the actual code needs edited as nissan's TP load scale = F(MAF / RPM) which I don't think would really work for MAP based.