In the world of 1990s JDM vehicles, V8 engines really arent all that common. Most of us are used to seeing inline-4, inline-6, or v6 engines in most JDM cars, but there were a few applications which used V8 engines. Compared to american V8 engines at the time, Japanese V8s were significantly more advanced.
As you may or may not know, the VH45DE is the first engine in the Nissan VH engine family. It was launched at a time when four and six cylinder engines were basically the only configuration you would find in a Japanese car.
The VH45DE was initially developed for use in the Infiniti Q45, and it was launched in 1989, the same year the Toyota 1UZ-FE came to market. At the time that it launched, the VH45 was a pretty advanced engine, using an all aluminum design with dual overhead cams.
The VH41DE was the second and final engine in the VH engine family. It’s based almost entirely on the VH45DE and they share a significant amount of parts. I don’t know why Nissan developed the VH41, but it’s more than likely they wanted something similar to the VH45 but with lower fuel consumption and a smaller package which could be more easily fit into smaller vehicle.
Specs and Internals
Starting with the cylinder block, both the VH41 and VH45 use the exact same cast aluminum 90-degree block. Notable features of this cylinder block include very deep cylinder skirts and a closed upper deck. The deck height is 220.35mm and the the length is 497.5mm.
For reference, the VH deck height is about 9mm taller than the deck height of an SR20 and it’s about 60mm longer. What’s really interesting is that the VH engines are most than twice as big in terms of displacement compared to an SR20, but weight less than twice as much.
To put it simply, VH engines provide a lot of displacement for their total engine weight.
Both the VH41 and VH45 are both very oversqaure, meaning bore is significantly larger than stroke. They both share the same 93mm bore, which makes sense because they utilize the same block, however, the VH45 uses a 82.7mm stroke compared to the VH41 which uses a 76mm stroke.
This puts their respective displacements at 4,130cc and 4,494cc, which is rounded to 4.1 liters and 4.5 liters.
Inside the engines, both the VH41 and VH45 you’ll find a forged steel crankshaft, forged steel connecting rods, cast hypereutectic piston, 6-bolt main caps, and a full-length girdle. To put it simply, the bottom of these engines are both very strong and arguably overbuilt for their needs.
It’s important to note that the bottom ends of these engines aren’t 100% identical, since the decrease stroke of the VH41 requires different length connecting rods and a different crankshaft throw in order to maintain the same deck height as the VH45.
Up to this point, the only major difference between these two engines has been the displacement, but the cylinder heads are also quite a bit different. One of the areas that wasn’t so great on the VH45 was the ports on the heads.
By the time Nissan was developing the VH41, they realized this problem and redesigned the ports on the VH41 heads to flow quite a bit more.
Both engines use a dual overhead cam design with four valves per cylinder and they both Nissan’s valve timing system. Compared to GM and Ford V8 engines of the time, the heads of the VH engines were far more advanced.
Really, the majority of the big changes are found in the cylinder heads where the VH41 is simply superior at making more power.
At the time the VH45 came out, it was supposed to be limited to around 280 horsepower, as per the “Gentlemen’s Agreement” which is still ongoing today. There a lot of people who claim the VH45 actually makes over 300 horsepower and Nissan underrated the power number in order to stay within the Gentlemen’s Agreement.
There rumors that the horsepower output was basically rated without VTC enabled, but the validity is questionable.
Since the VH41 has a smaller displacement, power output is somewhat limited and it outputs 268hp and 278lb-ft of torque. If you want to get really technical you can compare the power figures per liter of displacement, where the VH41 is superior, but this is likely from the improved cylinder heads of the VH41.
- VH41: 65hp and 67lb-ft per liter
- VH45: 62hp and 65lb-ft per liter
As far as applications go, the VH45 was limited to just the 1990 to 1996 Infiniti Q45 and 1990 to 2002 Nissan President, both of which were designed to to get Nissan into the luxury sedan market. The later version of the Infiniti Q45 used the VH41, as did the Nissan Leopard, Nissan Cima Y32 and Y33.
Today, you’ll find the VH41 and VH41 swapped into all sorts of vehicles ranging from the 240SX, 350Z, 300ZX, and many other vehicles including non-Nissan vehicles.
Compared to other JDM engines, the VH45 is not a popular engine to swap into other chassis, mostly due to the the sheer size of the VH platform. A dual overhead cam, 90 degree V8, takes up quite a lot space which makes it a little more difficult to swap into other chassis.
Even with the physically large size and limited aftermarket support, the VH platform is a great engine to swap into other vehicles, especially if you plan on drifting.
With superb reliability and a rev-happy engine, the VH45 is a good choice for motorsports applications such as drifting, but it’s still less popular than something like an RB26, Chevy LS, or Ford Mod motor.
It is possible to push the VH platform to around 350 horsepower naturally aspirated, but it’s not cheap and takes a significant amount of work. For those who boost, the VH is an awesome platform because the large displacement gives you a very wide torque curve compared to smaller displacement engines.
As far as major issues are concerned, there is really one significant problem with the VH45, and that’s the timing chain guide. In earlier VH45s, Nissan used a plastic timing chain guide which is notorious for breaking in high-mileage engines.
With the timing chain guide broken, the timing chain can skip a tooth or come completely undone, and the result is a blown up engine. Luckily, Nissan realized this issue and fixed it in the VH41.
Which One is Better?
To wrap this all up, it’s easy to remember that the biggest differences between the VH41 and the VH45 are the differences in stroke and displacement, as well as the better flowing heads on the VH41. The VH41 is also packaged a bit smaller and is ultimately more over-engineered.
Both engines are pretty lightweight for their displacements, they both have pretty strong bottom ends, and they both make a decent amount of power and torque for their size, especially compared to many American V8 engines of the time.
Because of how similar they are, I don’t think it’s really fair to definitively say that one engine is clearly better than they other.