How to increase RPM without damaging engine

[RagingMain]

I have some ideas but I was wondering what you guys think.
Reason being is power.
Since HP= Torque x RPM/5252 we can see by making it go faster we can get more power, especially for racing.

Our bikes make a lot of torque comparitively so lets say we were to get the RPM up to 12000 and I know my torque is 83 ftlbs

So 83x12000/5252 that would be 190 hp, kind of high but is getting more revs out of our engines possible.

Besides the valves floating all over the place I am assuming, we all know how that goes, there are quite a few other internal mods that would have to be done.

Sean can you chip in on this???

 

[naughtyG]

I reckon it'll spin higher very happily, and easily reach 11-12k. But, it'll also self-destruct, I think the small and big bearings would be the first weak link, followed by the pistons and rods.

Next will be the crankshaft bearings, and so on..

 

[satariel666]

I have some ideas but I was wondering what you guys think.
Reason being is power.
Since HP= Torque x RPM/5252 we can see by making it go faster we can get more power, especially for racing.

Our bikes make a lot of torque comparitively so lets say we were to get the RPM up to 12000 and I know my torque is 83 ftlbs

So 83x12000/5252 that would be 190 hp, kind of high but is getting more revs out of our engines possible.

Besides the valves floating all over the place I am assuming, we all know how that goes, there are quite a few other internal mods that would have to be done.

Sean can you chip in on this???

Before instaling the DYNA with rev limiter I hit 13k once lol
Not much more power above 9k I felt.

Those engines(stock) were not designed to such high rpm.
Just look at this dyno graph from stocker:
http://www.motorcycle-usa.com/photogallerys/VMaxHPDyno.gif

Torque is falling after 6,5k and power after 8k rpms.
Of course tou can rev them to even 13k but no gain there, loss even.

Reving this engine to about 12k require many many changes.
I doubt that stock heads can hold it.
Heads are the biggest problem. Im afraid that changing the cams only is not enough.

I reckon it'll spin higher very happily, and easily reach 11-12k. But, it'll also self-destruct, I think the small and big bearings would be the first weak link, followed by the pistons and rods.

Next will be the crankshaft bearings, and so on..

Bearings should hold on well but heads can explode...
Heads, internal parts of heads are to heavy and not balanced for that high revs.

Answer for question:
-cams
-valves(titanium)
-springs/retainers
-chains
-rods(titanium)
-pistons

Balancing staticly and dynamicly evrything what can be balanced.


Complety redesign the heads to make that reving useful.

 

[SpecOps13]

I've been thinking of installing a Sassy and setting the rev limiter to 8,000.
I don't see much need to strain the engine when the horse power is dropping
and there is that infamous O-Ring. My thought on more horsepower and torque
would be more cubic inches, not rpm.

 

[RagingMain]

Lets take for example the RSV4, yes I know our bikes are not sport bikes, just the engine

It is a dual overhead cam, 4valves per cyclinder, water cooled, 4 stroke, 65*, V-4 engine. 1000cc
Look familiar to anyone??? (except for the size)

Its redline is 12,500, max engine power 182 hp, RWHP 150.

What I am wondering is instead of all the money needed to make more displacement is getting it to breathe better at higher rpms and doing the mods necessary for higher revs.

Of course this wouldnt be of much use on the street, stop light races and such but for the quarter mile, naturally aspirated it would be a very lethal threat.
No one would expect a "stock" looking and stock displacemnt Vmax capable of such numbers.

This is something I am seriously considering pursuing and am asking for serious help from our forum.

With the right stuff I dont see why it couldnt be done:confused2:

 

[one2dmax]

Yes, the higher the RPM's the greater the "potential" for more HP. The effects working against this are of course the obvious which are parts failures. Some of that can be remedied by using stronger parts (Rods, Pistons, Valve Springs, ect...) but the real limiter for us is flow. Both in intake and exhaust. You can use larger cams and larger valves as well as bigger ports and carb bodies to help get the flow in. Then you can use custom exhaust to get the flow out. All of this will increase the RPM and power but will also raise the rpm range in which it makes it. So, it will be slower for most street riding then maybe even a stock engine and exhaust would be. BUT, get the rpm to 8-10K and hold on.

At some point the block and crank become the weak links which aren't as easily fixed though the new block girdle will help keep the block and crank living longer at higher rpm's.

Sean

 

[RagingMain]

Thanks Sean
Thats exactly what I am looking for
If our blocks arent strong enough then there is no need to worry about this.
Every thing else can be engineered to flow more.
The RSV4 has 48mm throttle bodies on an 1000cc engine
We all know what that does to our bikes uke:
But if we can strengthen the girdle, block, rods, pistons, etc etc
I think I am going to try this.
Will be a little while with my wedding coming up, gotta pay for that first
But until then most of this battle will be in designing it. I already have the fuel inection for it unk:

 

[one2dmax]

Lighter valves can go a long way to higher rpm's which I am not sure what's available out there. Larger valves too. Yamaha tried to get the lighter valves years ago with the 5 valve setup so they could cut valve weight. They held that design for many years and finally went back to the 4 valve setup (and lower rpm) and gained more power.

Super high lift cams and shim under buckets would be needed. Carrillo or even the new rod we are using now (Max Speed). The carrillo's are lighter which is a big factor. Some really high revving engines actually use SMALLER bores and strokes to lighten up the mass. The overall head design will be a big challenge since it's not designed already so retro work is harder to make work right.

Sean

 

[satariel666]

Lighter valves can go a long way to higher rpm's which I am not sure what's available out there. Larger valves too. Yamaha tried to get the lighter valves years ago with the 5 valve setup so they could cut valve weight. They held that design for many years and finally went back to the 4 valve setup (and lower rpm) and gained more power.

Super high lift cams and shim under buckets would be needed. Carrillo or even the new rod we are using now (Max Speed). The carrillo's are lighter which is a big factor. Some really high revving engines actually use SMALLER bores and strokes to lighten up the mass. The overall head design will be a big challenge since it's not designed already so retro work is harder to make work right.

Sean

How about the bottom end vibes?
IMO it has significant effect on high rpms.

And another clue.
Check the v-max piston stroke. Its 66mm while most modern sport engines comes with 53-55mm or so.
Whta do you think about shortening the stroke but geting bigger bore?

Another one.
V-max engine weight is about 100kg while modern sport bikes engines comes with about half of that.
Whta is realy heavy in those engines besides shaft drive?

 

[satariel666]

Thanks Sean
Thats exactly what I am looking for
If our blocks arent strong enough then there is no need to worry about this.
Every thing else can be engineered to flow more.
The RSV4 has 48mm throttle bodies on an 1000cc engine
We all know what that does to our bikes uke:
But if we can strengthen the girdle, block, rods, pistons, etc etc
I think I am going to try this.
Will be a little while with my wedding coming up, gotta pay for that first
But until then most of this battle will be in designing it. I already have the fuel inection for it unk:

And thats why secondary butterflies are used in lagre id bodies.

IMHO max 11k is what you can get without detonating the engine.

 

[RagingMain]

How about the bottom end vibes?
IMO it has significant effect on high rpms.

And another clue.
Check the v-max piston stroke. Its 66mm while most modern sport engines comes with 53-55mm or so.
Whta do you think about shortening the stroke but geting bigger bore?

Another one.
V-max engine weight is about 100kg while modern sport bikes engines comes with about half of that.
Whta is realy heavy in those engines besides shaft drive?

I have been spending a lot of time on the interweb searching this stuff out.

I have looked at shortening the stroke.
Our swept distance per bore is reduced so likewise is volume requiring an increase in bore to return to the same swept volume. The pistons are no longer travelling up as far, so to maintain CR either high crown pistons, planed head and/or block could be considered.
Piston pin will have to be raised and the skirt will have to be shortened.

All the internals will have to be lightened and strengthened.
The flywheel will have to be lightened.

 

[one2dmax]

Yes, a longer rod can be used to compensate for the shorter stroke which will also give a better Rod-Stroke ratio (it's good now anyway). Lighter pistons is one of the big things we are using with the stroker motor we are building. This should help us keep the same rev limit.

Sean

 

[RagingMain]

84 mm bore
55 mm stroke
1219 cc engine

Sean what is the biggest one could go on the bore with our bikes???
Also it seems like an "ideal" Rod/Stroke ratio would be 1.7:1 or there abouts.
A longer rod makes more torque with the same piston force, and since it's less angular than a shorter rod, reduces sidewall loading and decreases friction, less stress on the bearings. All of which adds up to more power.

 

[satariel666]

84 mm bore
55 mm stroke
1219 cc engine

Sean what is the biggest one could go on the bore with our bikes???

Im not Sean LOL :rofl_200:
but id say 87mm.

 

[RagingMain]

Im not Sean LOL :rofl_200:
but id say 87mm.

You a funny guy :biglaugh:

Oh yeah I would make this engine chain drive as well
dont know if I want a shaft drive trying to make 12k rpm

 

[one2dmax]

87 is the 1570 block and the absolute limit. 85mm is 1500 cc's. 75mm is probably the max stroke you are going to fit in there.

Sean

 

[satariel666]

You a funny guy :biglaugh:

Oh yeah I would make this engine chain drive as well
dont know if I want a shaft drive trying to make 12k rpm

:biglaugh:

87 is the 1570 block and the absolute limit. 85mm is 1500 cc's. 75mm is probably the max stroke you are going to fit in there.

Sean

87 couse the coolant space limit or theeres something more to consider?

Oh finaly got the all parts for covers and finished the carbs, Will try to assemble the carbs asap and make some testings.
Also covers are 70% complete.

 

[one2dmax]

Cool, Keep me updated on the carbs and when ready we will release it on the world!

Sean

 

[RagingMain]

Cool, Keep me updated on the carbs and when ready we will release it on the world!

Sean

Well since no one has volunteered to test the carbs I will be the first in line!!!!!! unk::clapping:

I will be your guinea pig :biglaugh:

 

[satariel666]

Intersting read!