flat plane vh45, possible?

[POE]

I want to change my vh45 to a flat plane. Does anyone know where I might be able to get my hands on an indy crankshaft? Or is it posible to have one made? I have a feeling this is not going to be an easy thing to come by.

[AZhitman]

That crank is different, Dave....

[ScottJackson]

POE, is that some sort of Dr. Strangelove reference? Are you organizing a mutiny of preverts? Why go with a flat plane crankshaft? I think it'd be very difficult ($$$$$$$$$$$$$$$+$$$$$$$$) to have one made. Don't forget, you'd also then have a different firing order and you'd need new custom cams too.

[AZhitman]

That's his last name, Scott.

[Mettler]

While it would be awesome, it wouldn't suit road use. You may as well try and score yourself a VRH35Z magnesium block while you're at it.

It'd also cost you approx. a billion dollars.

[elwesso]

ANYTHING is possible wiht enough money.

Even jessica alba...

[Mettler]

Even jessica alba...

Hahah and where do you propose to get THAT kind of money from ? :p

Mind you, she did recently admit in an interview that she loves getting it

[Clifton]

It would be expensive as you would need to have four cams made as well. A friend had some billet L28 Z cranks made about 10 years ago. It would be cool. Flat plane V8's sound awsome. It would cut some weight too.

[SSDwellah]

Good point Clifton. I also think that flat-plane V8s typically have balance shafts because there is a lateral vibration as opposed to the longitudinal vibration in a cross plane V8 (manageable by counterweights). The only real benefit you would get is a lighter rotating assembly so you could rev it up higher and quicker, but the VH already revs well for a V8 (especially when you go for stiffer valvesprings and a lightweight flywheel). So given all of that, I am not sure why you would want to spend all kinds of money to fabricate and machine a LOT of things for little benefit.

[David Steele]

1. Different camshafts are required due to change in firing order.

2. Crankshaft manufactuers usually have a minimum amount of cranks required to even commense.

Quote » The only real benefit you would get is a lighter rotating assembly so you could rev it up higher and quicker[/quote]Thats not the only ''real benefit'' It's intake and exhaust tuning its much easier.

[SSDwellah]

Okay well I'm not entirely sure so I'm not going to argue with you. I will say this though: the earliest V8's were all flat-plane - it was the more natural progression from in inline 4. When the cross-plane v8 was invented, it was considered superior in many aspects, and although it is actually more complicated, it became the de facto standard. Only a few manuafacturers use flat plance (I can only think of ferrari's and tvr cerbera off hand, not even modern lambos use them AFAIK).

That's not to knock the flat-plane if that's what floats your boat, I'm just saying you've got a whole lot of convention working against you.

[Mettler]

not even modern lambos use them AFAIK).

What modern Lambos have V8s ? IIRC they only make two models, the Murcielago V12, and Gallardo V10.

But yeah, everyone uses crossplane cranks, probably because they're easier to balance and more reliable.

[formula94lt1]

Actually the tuning of the exhaust isn't just easier, its far better. There are more vibrations with this setup. Im not going to say it will be rattling your fillings since Ferrari uses them, but I don't know if they use balance shafts.. my guess is no, but I could be wrong. There are gains to be had, F1 wouldnt use them exclusively if there werent, but I think it comes down to doing the research of how much exactly and if the cost is worth the benefit of the power gains(based on the application), sound, uniqueness etc...

[David Steele]

Actually the tuning of the exhaust isn't just easier, its far better. There are more vibrations with this setup. Im not going to say it will be rattling your fillings since Ferrari uses them, but I don't know if they use balance shafts.. my guess is no, but I could be wrong. There are gains to be had, F1 wouldnt use them exclusively if there werent, but I think it comes down to doing the research of how much exactly and if the cost is worth the benefit of the power gains(based on the application), sound, uniqueness etc...

There are not proven to make more power.

Ferrari doesnt use balance shafts as far as I know. '' V8's don't like to rev high'' Cross or flat plane ex racing F1 commentators say. You'll shake your teeth out with this configuration.

[formula94lt1]

I was using f1 to illustrate there being an advantage to a flat plane engine for tuning accuracy and ease, not that it wouldnt vibrate like hell at 20,000rpm. I dont imagine he was contemplating building an F1 engine. Ferrari uses the flat plane engine and revs to maybe 8 or 9krpm at most and having driven them before they arent lexus smooth but they leave nothing in the way of vibration to complain about. Its my opinion, and we are all stating opinions here, that if the harmonics were researched I think you could make something worthwhile and interesting out of it. The cost however might prohibit you from bothering if it wasn't being thrown into something special.

[David Steele]

I was using f1 to illustrate there being an advantage to a flat plane engine for tuning accuracy and ease, not that it wouldnt vibrate like hell at 20,000rpm. I dont imagine he was contemplating building an F1 engine.

I didnt either.

Quote »Ferrari uses the flat plane engine and revs to maybe 8 or 9krpm at most and having driven them before they arent lexus smooth but they leave nothing in the way of vibration to complain about. [/quote]Ferrari also uses high rod stroke ratios along with compact engines translate to = small diplacement 3.5 - 4.3

Why am I mentioning high rod rod stroke ratios? Because it doesnt magnify vibrations. It helps. But these v8's also have x2 the imbalance of a 4 cylinder.

I'd stay with the cross plane, if anything happened with your engine you have parts already to replace. Doing that custom crank. You'd have to get another crank made it would suck.

[formula94lt1]

I get the feeling we are both arguing correct statements towards a different direction. Basically he is right it will vibrate more, and be a hassle if anyhting breaks along with being pricey in the first place. I think if your pockets are fairly deep and you feel the need to create something fascinating, well youve got a pretty good platform. BTW with a custom crank the stroke and therefore displacement and rod length are your choice... I think it could be made more then reasonably within the average sports car driver's tolerance for vibration especially if its still compliantly mounted.

[Mettler]

Ferrari also uses high rod stroke ratios along with compact engines translate to = small diplacement 3.5 - 4.3

Why am I mentioning high rod rod stroke ratios? Because it doesnt magnify vibrations. It helps. But these v8's also have x2 the imbalance of a 4 cylinder.

2005 Ferrari F430 Spider:Quote »EngineType: 90° V8Bore x stroke: 92 mm x 81 mm (3.62 x 3.19 in)Unitary displacement: 538.5 cc (32.87 cu in)Total displacement: 4.308 cc (263 cu in)Compression ratio: 11.3:1Maximum power: 360.3 kW (490 hp/483 bhp at 8,500 rpm)Maximum torque: 465 Nm (47.4 kgm/343 lbs ft) at 5,250 rpmSpecific power output: 114 hp/l[/quote]F430 V8: 92 / 81 = 1.136:1 Bore / Stroke ratioVH45DE: 93 / 82.7 = 1.125:1 Bore / Stroke ratio

So the F430 engine runs the same bore/stroke ratio as a VH45, and with a huge 11.3:1 CR they're still only making 490HP at a whopping 8,500rpm.

What a piece of sh*t tbh, a 45 will produce numbers like that with less revs.

[zebee]

I like the idea.

I have 240z and have been uming and ahing about the power plant. I have a rb26 head that I was going to put on an rb30 block, but then fell in love with the VH45.

I just don't think the cross plane warble will fit with the 240z, so looked into the flat plane crank option

I figured If I destroke it to about 3.2 litres by using a 6 3/4 inch rod giving a stroke of just under 60mm, I will have a great engine for the 240z. This gives a rod to stroke ratio of about 2.9:1

By milling the head by 1mm, compression should be lifted up to 8.2 using a flat top piston (for forced induction). I could use a high compression piston from something like a N/A cosworth without having to mill the head by any great measure and still be able to run decent boost. In both cases would have to check on valve clearances.

I have found forged rods and pistons that will fit both scenarios off the rack.

I have the skill to design the crank and cams using cad/cam and have access to a 3d modeler if needed and mills/routers to do the work.

I want a drivers car, not a street machine. Something that I can take through the windiest routes with the engine singing. Probably won't ever drive it into town and will never see the 1/4 mile.

Talking to one of the guys with boosted vh45's in a 240z, his biggest problem was getting it to hook up. I hope to avoid this problem by purposely not building a torque monster and shifting both torque and horsepower up the power band

[Mettler]

Sounds like pipe dreams m8.

And you don't think the V8 sounds good in a 240?? Come again?? I reckon it sounds f'n brutal! More right than the sound of the factory L series engine!!

http://www.youtube.com/watch?v=4oNzb-PQ ... T-_f-TUc_M

[David Steele]

Sounds like pipe dreams m8.

And you don't think the V8 sounds good in a 240?? Come again?? I reckon it sounds f'n brutal! More right than the sound of the factory L series engine!!

[zebee]

LOL

Maybe

That car does sound nice though. Don't get me wrong, I love the sound of the v8. Have had several SBF's and think they are grouse, but don't think my 240z should sound like my falcon.

My sister is an industrial designer for a large firm in NZ with plenty of contacts and I have some well to do friends who build custom engines like this for ****s and giggles and are keen on the vh45 platform. I have done several engineering units myself. It is well within my capabilities and means to make these parts, but like you said, it may not be suitable for road use.

I will have to extrapolate the torque and power curves for that scenario and evaluate the valve train which will have to operate at least 1.5x as fast as standard.

Failing that, I will still use the vh45 platform mildly boosted, just cause its so reliable and balances the 240z well.

I have no time limit on this project and work between Australia and NZ, so have limited time to do actual work on the car and more time to play out scenarios like this, but it's worth a look!

[kscherbaum]

Just put 180 Degree Headers on it and call it a day... Cheap and sounds awesome too !

[Q45denver]

Beautiful Z-car. How do you manage to get 417 HP out of a L28?