[burnin_ruberv8]

Was wondering when D-series crankshafts reach it's limits with respects to RPM?
B-series cranks can spin daily at a rate of 11k and starts to have vibrations at 13k... anybody spun at those RPM's and where's our limit?

 

[singlecizam]

I just noticed something....2 out of 3 thread's you've started have had reference to a B-series... And I've yet to see a Honda engine make power anywhere around those rpm's... so whats the point?

 

[SOHC_STUDENT]

In our 1.5 or 1.6 rod/stroke ratio engines pump gas can't burn fast enough to push the pistons down the bore faster than around 9000 RPM.

You would need to run nitromethane to make power in those high RPM ranges.

Personally I wouldn't rev much past 7000 on a stock cam because power runs out before then and you'd be better off shifting.

I will only rev to 8500 on a Crower stage 3 cam. This is on a bottom end that's been professionally balanced to 10K RPM.

 

[burnin_ruberv8]

I just noticed something....2 out of 3 thread's you've started have had reference to a B-series... And I've yet to see a Honda engine make power anywhere around those rpm's... so whats the point?

But it's still better then a D... I'm bringing refrence to B for the sake of compraing.

I'm not intersted in making power at those high rpm's... I was just asking if it will hold it self up those RPM's like (9k-10k) and where is it's limits???
and actually... I'm not staying with the standerd low 1.5 R/S ratio...

 

[EG5[KRT]]

so far my z6 engine lasts to fuel cut which is 7700.. and that is at prolonged use.. i.e circuit racing..

dunno about going any higher tho...

 

[SOHC_STUDENT]

But it's still better then a D... I'm bringing refrence to B for the sake of compraing.

I'm not intersted in making power at those high rpm's... I was just asking if it will hold it self up those RPM's like (9k-10k) and where is it's limits???
and actually... I'm not staying with the standerd low 1.5 R/S ratio...

So you're going to de-stroke your engine but you can't spell standard? hmmm

 

[burnin_ruberv8]

So you're going to de-stroke your engine but you can't spell standard? hmmm

I thought about this and have contacted falcon cranks... they told me there is a rare possibility of breaking the crank during the de-stroke operation... so i thought... why not make use from the torque of the 84.5mm stroke (D15 by the way ) and increase the R/S by using a deck plate??? that's what i'm doin.

 

[93 red ls]

hmmm man d15 bored 84.5 id like to see it be a new one for me?

 

[SOHC_STUDENT]

I thought about this and have contacted falcon cranks... they told me there is a rare possibility of breaking the crank during the de-stroke operation... so i thought... why not make use from the torque of the 84.5mm stroke (D15 by the way ) and increase the R/S by using a deck plate??? that's what i'm doin.

A deck plate will increase the stroke length making the engine even more out of square which will increase piston speed and reduce the max RPM that pump fuel will support.

next...

 

[burnin_ruberv8]

What are you talking about?? :-|
a deck plate is simply a plate which is added above the block... it simply adds deck height... what's it got to do with crankshaft stroke???? :noway:
if it were added and all the bottom-end stayed the same... then all what you will be gaining is deck height + decrease in CR... I'm planning for Deck Plate + Custom Rods

 

[singlecizam]

which still doesn't make much sense......... Sounds like your trying to turn an ant hill into a mountian

 

[93 red ls]

lol i just dont see 84.5 mm happening in a D? ive seen 81mm and that was pushing it!

 

[SOHC_STUDENT]

What are you talking about?? :-|
a deck plate is simply a plate which is added above the block... it simply adds deck height... what's it got to do with crankshaft stroke???? :noway:
if it were added and all the bottom-end stayed the same... then all what you will be gaining is deck height + decrease in CR... I'm planning for Deck Plate + Custom Rods

There is no point installing a deck plate unless you want to sleeve the block and run a stroked crank. Llonger stroke = more oversquare engine.

Long stroke engines are about making torque not high RPM horsepower.

The D engine is really good at some things. Reving to 13K RPM is not one of them.

 

[burnin_ruberv8]

Ok... now... my goal is raising the R/S ratio right??? more specifically i want an R/S ratio of 1.70...
Then i need at least a rod length of 143.65 mm, cause by the R/S formula (Rod Length / Stroke) which means 143.65 / 84.5 = 1.70 R/S...
But i must be aware of piston position.. will fit or not?
So with the stock bottom-end the piston position is this ( Deck Height - Rod Length - Piston Compression Height - [Stroke/2] = Piston Position ) it will be like this:
207.45 - 134 - 27(D15Y2) - 42.25 = 4.2 mm BELOW deck... so the longest rod i can fit is 138.2 mm and this gives m an R/S ratio of 1.63 NOT what i want...

So at least i need a deck height of 212.9 to allow a rod of 143.65 to reach my gola and that means...
212.9 - 143.65 - 27 - 42.25 = 0 AT the deck!!!... and now i need custom piston valve relifes to give me safe piston-to-valve clearance... but that's the minimum deck height i HAVE to do.. it will be more...
That's it

 

[singlecizam]

is this physics.org or d-series.org? Im mean come on..... what is your goal or purpose with this motor.. because so far, none of this is necessary...

 

[burnin_ruberv8]

The rod length got nothing to do with the stroke...
a rod legth of 1000 mm won't move the piston but a specific amount of mm controlled by the crank stroke...
my idea is to get the deck height of the D15 207.45mm to 212.9 mm and fit longer rods... the stock D16 deck height is 212 mm
so if you think about it... it's simmiler to a D16 block with a D15 crank and an R/S ratio of 1.70.. got it looool

 

[burnin_ruberv8]

is this physics.org or d-series.org? Im mean come on..... what is your goal or purpose with this motor.. because so far, none of this is necessary...

I'm going with this motor to 200 whp

 

[SOHC_STUDENT]

The rod length got nothing to do with the stroke...
a rod legth of 1000 mm won't move the piston but a specific amount of mm controlled by the crank stroke...
my idea is to get the deck height of the D15 207.45mm to 212.9 mm and fit longer rods... the stock D16 deck height is 212 mm
so if you think about it... it's simmiler to a D16 block with a D15 crank and an R/S ratio of 1.70.. got it looool

OK so you're going to stroke the motor with a deck plate, sleves, rods, pistons and crank. You'll have spent thousands of dollars and it will be more out of square at 1.7 than it was at stock at 1.6 or 1.52. Pistons will be moving faster down the bore at 7000 RPM than they were on the stock motor so again, pump gas won't be able to burn fast enough to support high revs.

 

[s_18]

I would much rather spend the money on a B16 swap than going through all that...

 

[SOHC_STUDENT]

I'm going with this motor to 200 whp

People come on this board all the time saying 200WHP D. They talk about high revs, high compression, custom balanced bottom ends, they talk about ported heads and expensive valvetrain parts, they talk talk talk...

What you are proposing is a $10,000 + build. Good luck to you.