What kind of realistic horsepower can i expect if I build a VH or VK?

[Rainier]

I am thinking about buying a VH or a VK and building one up from the ground up and putting titanium rods, high compression pistons, ported heads, race cams, high performance intake from Kinsler and racing headers. Is it possible to get around 450-500 hp?

[defrag010]

on pump gas, you should be able to get at least 400 horsepower out of the motor, but titanium rods are way overkill and not suited for a build like that. You ill be better off with some 4340 billet I-beams

[ScottJackson]

titanium is touchy. You can't use some solvents to clean them and you can't scratch them or they easily develop stress cracks. Titanium rods are for F1 and Nascar engines... where the money grows on trees. You could get 500hp out of it. Basically copy the 5.0L BMW M5 engine. You'll need probably 12:1 compression (more if you're running it on alky or race gas), some nice big cams that let it breathe around 9000rpm, valve springs, the intake, headers, matched injectors... But yeah, it's certainly doable. If you could find the specs on the Ferrari F430 engine, that'd give you a good idea of what it will take.

[Rainier]

I have a 1999 Ferrari 360 challenge car that caught on fire and I thought why not put it in there. since my F430 challenge car has the 4.3 liter 90 degree v8.

[Mettler]

Are you talking about power at the wheels, or flywheel?

[Rainier]

At the flywheel is fine with me

[Clifton]

If you could find the specs on the Ferrari F430 engine, that'd give you a good idea of what it will take.

Flat plane crank, and heads the VH will never have.

[Raxephon]

Flat plane crank, and heads the VH will never have.

I have a somewhat stupid question to ask & I'm unfamiliar with Ferrari motors.

Whats so spectacular about the heads?

[T45]

They're extremely tiny...

http://www.youtube.com/watch?v=9f6YxAvcxhU

[DeXteR]

fantastic response!! i'd like to nominate it for "nico's post of the day"

[Clifton]

I have a somewhat stupid question to ask & I'm unfamiliar with Ferrari motors.

Whats so spectacular about the heads?

Port shape/flow. You can have whatever bore/stroke and rod ratio but the power is in the head and you can only do so much with a factory port as far as porting and shaping. Not trying to say the VH is bad but you can only do so much with what you have.

[Mettler]

Flat plane crank, and heads the VH will never have.

Would be nice to be able to compare the heads to see just how different they are! Rainier, do you have pictures of your F430 engine out of the car at all?

VH heads are pretty badass... with the VH being related to indy & le mans engines, I'd wager that they hold up pretty well in comparison to the likes of Ferrari. Of course the Ferrari design will be superior, but I'm wondering just how huge the difference actually is. (For example, 1UZ heads wouldn't even come close to comparing!)

Remember the F430 engine produces 490HP @ 8500rpm, and that's with 11.3:1 compression ratio. We have guys in NZ producing similar power @ similar revs with VH41s running only 10.0:1, no VTC, minimal porting, and carburettor. Of course, the Ferrari engine's powerband will be significantly wider due to their clever variable valve timing system etc... but it shows the Nissan heads are pretty damn capable.

[clip14]

Would be nice to be able to compare the heads to see just how different they are! Rainier, do you have pictures of your F430 engine out of the car at all?

VH heads are pretty badass... with the VH being related to indy & le mans engines, I'd wager that they hold up pretty well in comparison to the likes of Ferrari. Of course the Ferrari design will be superior, but I'm wondering just how huge the difference actually is. (For example, 1UZ heads wouldn't even come close to comparing!)

Remember the F430 engine produces 490HP @ 8500rpm, and that's with 11.3:1 compression ratio. We have guys in NZ producing similar power @ similar revs with VH41s running only 10.0:1, no VTC, minimal porting, and carburettor. Of course, the Ferrari engine's powerband will be significantly wider due to their clever variable valve timing system etc... but it shows the Nissan heads are pretty damn capable.

mettler what other mods are the nz people running to produce 490hp?are they still running pump gas?

[Clifton]

I know this is a VH forum and people here are very biased to the engines they run and have a hard time accepting an engine for what it is.

Is it related to an Indy engine, sure they are both V8's made by Nissan. I'm not saying they aren't good, but a cams and compression will only get you so much. Ya, porting will gain some more. The F430 will idle smooth and pass CA emissions. Cams that will get a VH45 close to 114hp per liter (513hp) probably won't be so street friendly and idle nice either. You need revs to make that kind of power and if the heads don't flow, it won't make it. Are they good engines, sure, but they were designed for a different application from the start.

There are alot of engines from Nissan(VG30E/VG30DE), Toyota (7M/2JZ), and Honda (lots) that with just a few years between have a huge power increase. Most of the older engines will never make the power the newer ones can make even with cams.

[Mettler]

mettler what other mods are the nz people running to produce 490hp?are they still running pump gas?

It's variable, the more hardout ones are ~500HP+ & have more extensive mods, some run a bit less because they spend less on their builds. Typical mods are cams (max 12.7mm lift), valvesprings, porting, decompression pistons (10:1 max), aftermarket rods, 9000rpm (not everyone runs aftermarket rods, and many with stock rods are also revving this high like the racer I bought the 45 crank from), 107octane avgas (some people run 98 octane pump fuel), carburettor, different manifold, long headers.

That's it, pretty much just breathing and huge revs. Of course, they all run the supporting stuff like big fuel system, dry sump etc, but as for actual power production, there's not a huge amount in it.

[T45]

Don't forget the cool homemade cam driven distributors!

[nismology]

I know this is a VH forum and people here are very biased to the engines they run and have a hard time accepting an engine for what it is.

Is it related to an Indy engine, sure they are both V8's made by Nissan. I'm not saying they aren't good, but a cams and compression will only get you so much. Ya, porting will gain some more. The F430 will idle smooth and pass CA emissions. Cams that will get a VH45 close to 114hp per liter (513hp) probably won't be so street friendly and idle nice either. You need revs to make that kind of power and if the heads don't flow, it won't make it. Are they good engines, sure, but they were designed for a different application from the start.

There are alot of engines from Nissan(VG30E/VG30DE), Toyota (7M/2JZ), and Honda (lots) that with just a few years between have a huge power increase. Most of the older engines will never make the power the newer ones can make even with cams.

I've not, but have you seen VH head flow figures?

[clip14]

It's variable, the more hardout ones are ~500HP+ & have more extensive mods, some run a bit less because they spend less on their builds. Typical mods are cams (max 12.7mm lift), valvesprings, porting, decompression pistons (10:1 max), aftermarket rods, 9000rpm (not everyone runs aftermarket rods, and many with stock rods are also revving this high like the racer I bought the 45 crank from), 107octane avgas (some people run 98 octane pump fuel), carburettor, different manifold, long headers.

That's it, pretty much just breathing and huge revs. Of course, they all run the supporting stuff like big fuel system, dry sump etc, but as for actual power production, there's not a huge amount in it.

Decompression pistons?? that seems a bit counterintuitive

great to hear that a fair amount of power is available with fairly straightforward modifications. Were you able to gleam any information about their cam specs which you may be able to apply to your cam development?

[Q45tech]

All about valve curtain area which can be accomplished with [cams higher lift] or just a larger diameter valve.

Do some research on valve diameter, stem diameter and lift what creates the curtain area. Measure and Plot the air flow speeds inside the head especially short radius.

The area of the intake valve(s) is the ultimate determining factor, but this assumes that the intake valve is fully opened. By this, I mean that it's lifted off the seat by at least 0.25 times the valve's diameter, which is where the valve "curtain area" (the circumference of the valve times lift) equals the area of the valve itself. This should allow the valve to flow at its maximum.

Four-valve setups take advantage of more of the cylinder area, but almost as importantly, they suffer less from shrouding since the smaller diameter of the valves doesn't as closely follow the cylinder wall (the valves can shroud each other, but that's less of an issue

1.5 " valves need .375" [9.5mm] lift and oem is 0.390" or 9.9mm brand new and valve guide side to side play is tested at 10mm lift so we can be assured that 10mm lift is possible at least at 6,000 rpm or 6900.

When you track down every parameter you'll see the intake runners and plenum tuning to peak torque at 2,000/4,000/6,000 rpm is the main restriction.....cams only help 1/2 as much as you would think because the reflected wave comes too early and allows a tiny back flow at redline which just gets worse as you raise rpm without redesigning the intake tract.

Change runners and plenum leave cam alone until you get them correct for new rpm.

10 day free demo software:http://www.performancetrends.com/download.htm#pfa

I'll be back later

[Mettler]

Decompression pistons?? that seems a bit counterintuitive

Stockcar racing has been around for decades, before these fancy alloy multivalve V8 engines became available, hence the rules are still set up to allow it to be fair and affordable for people using the oldschool gear, that's why engine specs such as displacement, valvelift, compression ratio, fueling, removal of computers & so forth are all strictly regulated, otherwise the VH would pretty much dominate.

Presently, the VH & the top shelf Ford SVO engines are actually the ones that dominate.

Were you able to gleam any information about their cam specs which you may be able to apply to your cam development?

Yeah... heaps, except with what I'm doing I won't necessarily need to lean too heavily on their work. I'll probably go with specialist advice mixed with Q45tech's advice for the exhaust cam profiles, but part of the fun is experimenting with things.

[Q45tech]

After some serious research and phone calls it appear that cams alone without reoptimizing the runners and plenums will leave 18% of usable HP on the table at 8,000 rpm...............the exhaust manifolds are short tuned so not fixing them will be less afactor say 7-9%.

The TB and its Helmholtz pipe to plenum will be a restriction also.

All in not redesigning tuning might leave you 30% short of possible 8,000 rpm HP regardless of what cams you have made.

With everything right 90 lb/ft per liter is doable [400lb/ft] with a 12% loss in VE at 8000 rpm and a torque peak of 6200 rpm ..................8000/5252= 1.523 x 350= 535 HP.

[Mettler]

After some serious research and phone calls it appear that cams alone without reoptimizing the runners and plenums will leave 18% of usable HP on the table at 8,000 rpm...............the exhaust manifolds are short tuned so not fixing them will be less afactor say 7-9%.

Are you saying 18% less HP than what's potentially available at those revs, or literally only 18% of that figure? Sounds like a huge effect!

How much would the 4-1 headers with long runners affect your percentages and the helmholtz effect, when you account for increased overlap?

The TB and its Helmholtz pipe to plenum will be a restriction also.

I'll have to have a look where this pipe is, I'm not sure my 41 has quite the same bits on the intake. I'll check up on some old photos and see if I can't identify the part that you're describing, as I may have changed it already.

All in not redesigning tuning might leave you 30% short of possible 8,000 rpm HP regardless of what cams you have made.

With everything right 90 lb/ft per liter is doable [400lb/ft] with a 12% loss in VE at 8000 rpm and a torque peak of 6200 rpm ..................8000/5252= 1.523 x 350= 535 HP.

What do you think would be the ideal plenum volume and runner length to suit a set of hot cams optimised to rev right out? I actually don't want HP peak to hit at 8000rpm, I want it to be a bit earlier like 6500-7000, and the VTC to keep the torque consistent to 8000.

It seems copying the F430 engine's style of intake plenums might be a good way to go, except modify runner length slightly to suit your calculations for the reflected waves.

One problem though, is that I was hoping to retain a decent amount of low end torque by keeping the standard manifold. If I changed to an intake design that squeezed that additional HP out at the top end, would that remove a bit of that low end and more or less shift the powerband up?

[qsiguy]

I read somewhere a while back that a Ferrari engine designer was involved with the design of the VH. Has anyone else heard that?

[Clifton]

400 hp maybe, 400ft/lbs from a 4.5, no way with out boost.

As for cams, it's not just the lift but duration. If the ports drop off flow at .400" there isn't much benefit in lifting them another .100", the duration would have to be increased too and have more overlap (on n/a), that's when the nice idle disappears.

[Mettler]

You want to be careful just how much duration you actually have, as you can hamper performance across the powerband if your compression ratio isn't high enough to support a long duration. I'm designing cams to work most optimally with 10.2:1, tho of course, any profiles will be possible providing they're compatible with the valvetrain.

And I reckon 542N-m is totally reasonable with a 4.5 running that kind of efficiency!

Interesting that at 9.5mm valvelift, the curtain area = the valve area... isn't 9.5mm real close to standard? So are you suggesting that any further benefits gained by increasing this out to 12.7mm are more due to reduction of valve shrouding, rather than additional port flow?

[Clifton]

You want to be careful just how much duration you actually have, as you can hamper performance across the powerband if your compression ratio isn't high enough to support a long duration. I'm designing cams to work most optimally with 10.2:1, tho of course, any profiles will be possible providing they're compatible with the valvetrain.

And I reckon 542N-m is totally reasonable with a 4.5 running that kind of efficiency!

Interesting that at 9.5mm valvelift, the curtain area = the valve area... isn't 9.5mm real close to standard? So are you suggesting that any further benefits gained by increasing this out to 12.7mm are more due to reduction of valve shrouding, rather than additional port flow?

You reckon wrong. For an n/a gas engine you need displacement to make torque. Even a 5L 500 hp BMW doesn't make 400 ft/bs.

Now I really question your cam ideas. Increasing the lift without knowing the port flow per .100". You may be maxed just over stock. As for duration. I know alot of people running what you may consider alot with less than 10.5:1. Some 280-300* adv (270-280 @ .050"). The few ft/bs lost at 2500 rpms doesn't matter much as most of these engines were put into cars that originally had half the CC's and it will still have double the torque of the previous engine even with a slight loss down low. It will carry the torque curve farther into the power band though and that's what will need to happen to make more power.

[trix]

You reckon wrong. For an n/a gas engine you need displacement to make torque. Even a 5L 500 hp BMW doesn't make 400 ft/bs.

Actually, the BMW M5 V10 5 litre generates 383 pound feet/519Nm@ 6100 RPM. Not 400 pound feet, but it's close.

[Q45tech]

Even the V10 was designed to be in compliance with idle and cruise emissions and at least 100,000 mile cold street start gasoline durability.

On a per liter basis the V10 is barely 3% more torquey than the 4.5 Infiniti engine because of the above legalites.

Dinan sells a mod package to get the torque up to 415 lb/ft NA at a relatively low 5,000 rpm while still meeting CA emissions.

[Mettler]

Now I really question your cam ideas. Increasing the lift without knowing the port flow per .100". You may be maxed just over stock. As for duration. I know alot of people running what you may consider alot with less than 10.5:1. Some 280-300* adv (270-280 @ .050"). The few ft/bs lost at 2500 rpms doesn't matter much as most of these engines were put into cars that originally had half the CC's and it will still have double the torque of the previous engine even with a slight loss down low. It will carry the torque curve farther into the power band though and that's what will need to happen to make more power.

Question away! Have a look at some of the cam specs as used in superstock race engines, they are increasing lift quite a bit and getting huge gains. I won't need to rev as high as the 4.1s to see these gains overall because of the 4.5's additional stroke causing faster piston acceleration away from TDC and therefore higher intake charge velocity.

As I said, any cam profile is possible by being able to design it on the PC. If you have a different idea of what you want to see in a cam profile, you can spec it to me and I can draw it up and show you what it looks like running in the simulation. I have goals for my build and a pretty good idea of what I need to meet those goals, and one of them is to retain a big fat powerband for my street motor, in my street car. Absolute maximum possible peak power isn't the goal, but rather, excellent driveability is.

My research accounts for the engine's characteristics in both the advance and retard positions of the intake cam, and therefore some level of compromise has to be made with the profile to allow the engine to work nicely in both conditions.

Sure I want to rev it to 8000rpm, but I also want it to be responsive just off idle. I don't mind sacrificing a bit of peak power to retain great low end... I don't want to have to launch my car every time I go to take off just to get fast acceleration from standstill, or to do a nice smokey skid.

Also.... cmon man, you should really describe things in metric if you're dealing with a VH seeing as they're a metric built engine.

[ScottJackson]

I think comparing the F430 engine to the VH isn't that far off. I'd like to see and hear a VH head on a flow bench. I'm no engine building pro, but there are plenty "good ol' boys" who can tell when a port has maxxed out on a flow bench just by closing their eyes and listening. I can't imagine the stock cams are anywhere near the peak valve lift that the VH ports/valves can handle and keep making power. The ports are such a straight shot at the valves and decently sized for a 4.5L engine. And a flat plane crank may make great exhaust sound while also letting the engine rev a little quicker due to less weight, but it won't make more hp than the VH crank. To me, the proof is in the pudding... that is, guys down unda have been hot rodding them with great results. I like lots of old domestic (U.S.) V8s and I like the VH. They all have upsides and downsides. As for a small displacement V8 that can make good mid and top end power, I think the VH is a fine engine.