Despite the title of the domain, the new website we started is intended for VH41s and VH45s, we may add another domain or 2 and have it link to the same website.

Anyway, Im going to be writing some techincal informaiton.... Please critique/add as you see fit, because THIS is the information thatwill go onto the portal. Obviosuly it will be spell checked and formatted nicer, but i just wanna get the nitty gritty going. Some of this stuff I'm pulling out of my butt so if its wrong please let me know.

What is the VH?

- The VH series engine was used in the early 90s up until 2001. The Nissan VH was used in the following models.

1. Infiniti Q45- 1990-1996- VH45DE- 1996 had no VVT in the US.2. Nissan J-Ferie- (not sure on production times of the J)- VH41DE3. Nissan Cima- (not sure on years)- I think both VHs were offered4. Nissan President (1989-2001)- VH45DE5. Infiniti Q45 (aka Nissan Cima)- 1997-2001-VH41DE*

- The VH series motors is probably one of Nissan's best kept secrets. Each motor was individually balanced and dyno tested from the factory, and its tolerances exceed that of most Mercedes-Benz AMG motors.- Rated at 278HP from the factory, the VH45DE actually makes more HP than it is rated at. We see people make 240-250 WHP on a stock VH with the automatic trans in the Q45!

Basic specs

VH45DEClosed deck engine6 bolt mains, 2 are crossed274.22CI, 4494CCBore/stroke- 93x82.7mm (3.66/3.256in)Multiport fuel injection with equal length runners370CC injectors2 compression piston rings1 oil piston ring10.2:1 Compression RatioIndividual runner exhaust manifolds

Camshafts:

Inlet:Lift = 9.9mmDuration = 248°IVO 0° BTDC IVC 68° BTDC38mm diameter

Ex:Lift = 9.9mmDuration = 248°EVO 60° BBDC ECV 8°ATDC32mm diameter

Q45techThe 90-95 Q45 uses an intake cam of 248 with 0 or 20 BTDC [vvt wrote: so it closes at 112 or 92.

The exhaust is also 248 and closes at 8 ATDC so opens at 120 ATDC.

Don't have a 4.1 FSM on hand but remember~~ 236 degrees duration.

Modern OBD2 engines [Q41 etc] use less duration and much less overlap.

Not necessary with big multiple valves, as the SUM of the opening flow is what counts.......the curtain area = ratio of imaginary cylinder [valve diameter less seat , less valve stem, times lift. The problem with big valves is like big cams at idle.

Extra Lift is the usual variable added to performance cams [for 32v engines]vs. duration........but tiny margins in valve to pistion clearances when extremely hot, thus flycuts in pistons.

The exhaust cam durations on both engines could be increased to gain 5-10% at the expense of idle........as the vvt engine idles with a only 8 degrees overlap vs 1500-4500 at 28 degrees and back to 8 above 4500....another 10-15 degrees might open it up to above 6200 rpm performance.

All the same with the VH41 except they came with metal timing guides from the factory, smaller stroke, and only came with 270cc injectors.

*NOTE: The VH41 was also produced in the early 90s, but not in the US. It was put in the Nissan Cima, Nissan J-Ferie, as well as a couple other auto's. This version of the VH41 is very similar to the VH45 except with the differences listed above. The VH41 in the Y33 (97-01 Q45 in the US) is considerably different. Mainly the intake and exhaust is different for emissions/OBDII purposes. However the basic long block engine design remains the same.

ideally, id like to add more info about the cams, which I do not have and honestly im not really sure about all that stuff with the cams....

Aftermarket support:

- Escort makes low compression forged pistons, however they are very expensive and somewhat hard to get ahold of.- Thomas Knight of Miami, FL builds a roots type supercharger for the 90-95 VH45DE's. This kit has been built and run on an old Q45 and can be remade to run on any VH setup. Probably the best setup if you intend to keep low boost (within the stock injector range of 400-450HP)- Inner valve springs from the GTiR SR20DET fit on the VH heads. This allows you to run a stiffer spring on the stock cam profile to reduce valve flutter under boost.- VQ30DET Pistons will (allegedly) fit into the VH and give a lower compression ratio- NISMO side feed low resistance injectors will fit into the stock fuel rails. Basically any injectors that fit into the SR20DET or VG30DETT will work in the VH

VH Capabilities

Despite what may be said, the overall VH scene remains sort of arbitrary. Nothing has really been proven, but there are plenty of people out there with fairly stock motors running big power. What your VH is capable of handling as far as HP is concerned more depends on its condition. The VH's do not take kindly to bad oil change habits....

What we do know:

- The motor has no problems handling any power up to the stock injector capabilties (370cc injectors @ 450HP). 100-150 shot nitrous, 10lbs of boost and so on dont really seem to phase this motor too much. - The motor has sort of a large road block at the 450HP area, due to the injectors and high compression.- With a lowered compression ratio and slightly different cams (mainly stiffer springs), the stock internals are capable of a large amount of power.

Transmission options:

Automatics-- the VH came with the RE4R03A automatic trans from the factory, same as the 300ZXtt with slightly different gearing... Its a fairly stout trans as far as factory auto's go.... There are many places in the US and abroad that can rebuild them to handle big power. I recommend getting a billet TC if you are running any big power.

- One of the members on the forum is running a powerglide trans.

Manual Trans- Most popular is to make the 5 speed manual from the 300ZX, the flywheel and clutch setups will bolt to the motor via an adapter plate and spacer.- Another member is using a custom fabricated bellhousing to a 6 speed supra gearbox with a custom flywheel and clutch.

What people are doing: (please add your details), this is only for people that actually have running . Ideally id like to get a few pictures of the peoples rides. maybe it would inspire people to get their stuff out and post up.

Wes from Indiana is running 150 shot of nitrous on his completely stock VH45 and level 10 transmission.

Rick from the east coast is running 150 shot on his completely stock engine and transmission.

Slim from Atlanta is running the following setup:- Twin turbo VH45DE (VH45DETT) swapped into a 300ZX Z32- Custom adapter plate, twin turbo 5 speed manual- Twin T28 turbos- Front mount intercooler- Custom rear sump large capacity oil pan.- Approx 8-10 lbs of boost- Has proven to be reliable for long drives, 170MPH, and summer atlanta traffic

A member from Australia is running a cerntrifugal supercharged VH45 in a 1994 Skyline with the automatic transmission

Ezekial from Austrialia is running a single turbocharged VH45 in a S12. The car is currently undergoing a rebuild to produce even more HP than before.

Nice Wes, a couple of notes:

1. The RB25DET also runs the same type of side feed injectors, and is another potential source for aftermarket injector options.

Furthermore, a guy in New Zealand has found that early 1990's Subaru Legacy Turbo injectors will also fit straight in, and are something like 500cc's. Nice cheap option there.

2. I am running a 5 speed supra box, not 6.

3. It should be noticed that the timing chain setup on the VH41 differs significantly to the VH45, with the camshafts on each cylinder bank being driven by a stronger, duplex chain on the VH41.

4. You may want to make mention of the differences in ports between the various generations/versions of the engine.

5. Being all alloy, the engine weighs 220kg less manifolds, which is roughly the same as the cast iron RB engine, and is shorter. An RB26DETT engine would weigh more than this. This makes the VH engine an excellent choice for conversions.

6. The front-sump design allows it to fit nicely into an R31 Skyline & other Nissans with this same front-half chassis (think S13 Silvia etc.)

7. The ECU is tuneable like other Nissans, with conversative factory fuel and ignition mapping being a key to unlocking a lot more potential power.

thanks shaun.... ill take note of that....

I think i will also pointout that there is no evidence of any weakness of any VH cam drive setup.... so the duplex chains may be an advantage, but not really a "selling point" if you will. Just want to be truthful, not trying to dog the VH41 (which I do agree that a VH41 block with all other VH45 stuff is the way to go).

i also figured about the RB stuff, but i wasnt sure. The Subie injectors are good info too.

I know ^_^ The duplex chains are just something I like to rub in VH45 fans' faces every now and then

Good info though, and you could use the photos of the internals as supplied by various people on here too, with dimensions etc.

Ezekial says he's going to be photographing every step of his build process, so those could be some nice pics to have access to as well!

310,500 miles on the 16.7 year old engine chains with just a guide up grade at 100k. Modded ecu since 1994 [7300 rpm redline]..........they may be stretched but enough durability for most.

I've not once said they were weak guys... it's just kinda like laughing at the guy with a tungsten alloy front door to his house, because I have a diamond one... if you get the analogy :p

Mettler wrote:
Good info though, and you could use the photos of the internals as supplied by various people on here too, with dimensions etc.

yeah! I didn't do all that measuring and pissing my boss off by not doing work for my thread to be forgotten! haha

zerothread?id=179262

that is your master dimension thread.... ill add that info on here sometime.

In fact, this might be a bit of an ambitious project/suggestion but....

If anyone has a spare VH engine lying around, and is willing to pull it apart to every last bit, and measure all of it up for me.... I'd be happy to model the entire thing in 3d using Solidworks and make the stuff available !

What do you guys reckon ? Imagine if I had the engine assembly in 3d, and what awesome parts I could design for it !

how does solidworks compare to Pro/Engineer? (slightly off topic)

I don't know, but I've been using Solidworks for 5 years now and Maya for about 3, and have become pretty proficient at both.

I've tried lots of alternative 3d packages including the much overhyped Inventor, which I found to be crap.

Pro Engineer looks nice, but never having used it before and now that I'm used to Solidworks & Maya I think I'll stick to them for their respective purposes as they get upgraded & new features introduced.

With sw 2006 they've just introduced really nice support for cams and gears, which will enable me to design mean as camshafts amongst other things.

So yeah, piece by piece, I'd actually love to model a complete VH41DE and VH45DE !

you ever used lightwave? I'm taking a class on lightwave9 right now and it's pretty sweet.

I FINALLY did something with all those great pics that Defrag sent me and put them on my iServe account.

You may like to add the following

Generation3 4G63 lifters are identical and so 2 x 4G63 solid lifter kits is possible. SR20DET lifters look similar but i have no measured them up! I wouldnt be surprised if they are the same.

http://www.performancesprings.com.au/ Performance Springs Australia can provide with upgraded valve springs to suit whatever cam profiles you provide ...

http://www.acl.com.au/ACL has 3 different thickness triple layer metal headgaskets available to suit VH45DE at around $100 AUD per bank

http://www.heat.com.au/ Heat Treatment can crack test / stress relief and nitride the VH 24ish kg crankshaft for $100 AUD. Then follow with straightening and journal linish

http://www.qri.biz/content.aspQuantum Racing Industries can supply CP Pistons with any chosen dome/dish to suit whatever static compression for roughly $1500 AUD to suit VH

http://argorace.com.au/Argo can make custom conrods to suit VH engine and any desired pistons. I cant see this being necessary unless you are producing over 800-900 engine hp. For reliability though ... great idea

As mentioned already, RNN14 GTiR SR20DET inner valve springs fit. They can be had second hand for about $50 AUD for 32! GTiR inner valve springs seats can also be used. The Intake ones have to machined roughly 1 mm on inner diameter to fit over the head/guide. Seats can be purchased brand new from Nissan for roughly $30 AUD for 32!

ARP RNN14 GTiR Replacement Head Studs can be used in the VH45 engine

Tighe can make a grind to suit your camshaft needs. Or hard face to retain factory base circle and hence factory lash and HLA's

Factory Port Matching in the VH45 engine is not far off embarressing!

Like any engine ... conrod bolts should be replaced and conrods close & honed during rebuild. Head bolts should also be replaced as they use angle torque (bolt stretch) method

just a corection - 4g63 lifters are taller and are not the same diameter as the VH45 lifters. I thought I took a pic of them together, but I guess not.

thanks... ill add that stuff!

defrag010 wrote:just a corection - 4g63 lifters are taller and are not the same diameter as the VH45 lifters. I thought I took a pic of them together, but I guess not.

i'll take a photo!

VQ30DET pistons in a VH

zerothread?id=127315

Hmmm, it's important to know the compression height, deck height, and stroke of the VQ30DET so that we can establish what length conrods are required, and whether the VQ conrods can be used.

compression height of the pistons would be enough ... i've tried to order one in ... need a working part number ...

I can do it if you tell me what the VQ30DET was in...

elwesso wrote:I can do it if you tell me what the VQ30DET was in...

Nissan Gloria Y33,Y34 Nissan Cedric Y33,Y34 Nissan Leopard Y33

Hmm i was able to pull up the Y33 cedric and gloria, but neither of them list the DET as an available engine... I'll keep looking though!