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Old 09-06-2012, 09:35 PM
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Default Why not 12,000 rpm?

Formula 1 race cars have ultra-sophisticated engines that turn around 18,000 rpm, and have per-cylinder displacements roughly twice our one-lungers.

Current sports bikes easily turn 14,000 rpm with motors perhaps one and a half times our displacement on a per-cylinder basis.

Yet for some reason, unless I am mistaken, the most radically modified go-kart engines only spin around 8,000 rpm.

So why not 12,000 rpm? That's a nice round number.

What holds us back? The valvetrain? Connecting rods and pistons? Splash lubrication? Breathing capacity? Something else?
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Old 09-06-2012, 09:59 PM
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What holds us back?
Everything you mentioned.
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Old 09-06-2012, 10:08 PM
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Everything you mentioned.
Then what has been the obstacle in overcoming those problems?
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Old 09-06-2012, 10:36 PM
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Old 09-06-2012, 10:50 PM
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Industrial engines are usually meant for industrial applications where power/cost and efficiency are the largest concerns.

Faster spinning engines are generally under higher load, which requires stronger parts, closer tolerances, better lubrication systems, cooling systems, etc... which all costs money. Most engines are generally more efficient at the lower end of their RPM range as well.

So we take an engine that wasn't designed to spin fast, and make it spin faster, replacing a few key parts. But the design itself is limited too. Look at the bore x stroke of an industrial engine, then look at a race engine - then do the same for compression ratios, ignition advance, cam timing and duration, etc. - They may both be gas engines and work on the same principal, but they're very different in design.
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Old 09-06-2012, 11:58 PM
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Quote:
Originally Posted by Iron John View Post
Yet for some reason, unless I am mistaken, the most radically modified go-kart engines only spin around 8,000 rpm.

So why not 12,000 rpm? That's a nice round number.
Your mistaken, quite a few racekart engines will rev above 12,000 rpm, no problem.
The Tag Leopard go kart engine will easily rev to over 15,000.
Here's a link to the specs: http://www.remoracing.com.au/product...rillaleopardrl
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Old 09-07-2012, 03:10 AM
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Originally Posted by Iron John View Post
So why not 12,000 rpm? That's a nice round number.
8000 is a rounder than 12000; it's made up of all circles. What's rounder than a circle?
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Old 09-07-2012, 03:28 AM
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Anything is possible with enough time and money

U could make these engines do 12000
When u are finished u would be left with a totally custom made engine with a redesigned lubrication system, water cooled, re bored/new block, internals with much closer tolerances and completely differant desingn and a new method of getting gasses in and out
This engine is related to the original by the coulings

anything is possible
But it is much easier to leave this to the big company's with all the technology and skills

EDIT
an F1 engine only runs for a few hours once a month or so then it is scraped at the end of the year
And to a point sports bikes only have a life of 5-10 years with a serious routine of services and looking after it

An industrial motor is designed to sit in a puddle on a building site and chug away for 20 years where people kick it to start it and a service is re filling the fuel tank
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Old 09-07-2012, 05:23 AM
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Quote:
Originally Posted by fowler View Post
EDIT
an F1 engine only runs for a few hours once a month or so then it is scraped at the end of the year
And to a point sports bikes only have a life of 5-10 years with a serious routine of services and looking after it

An industrial motor is designed to sit in a puddle on a building site and chug away for 20 years where people kick it to start it and a service is re filling the fuel tank
To add to that, a F1 engine has to be heated to near running temperature before it can even be started, this involves running heated fluid through the engine. The tolerances are so tight that the engine practically wont start from cold...it would likely rip itself apart. And even with that the engines arent reliable at all if you compare them to a standard car engine.

From memory an F1 engine will usually go for about 2000km before being useless....maybe more, maybe less. Roughly 2000 though. By this point it has generally exploded, blown a crank, overheated, destroyed its bore etc. If you scale that down to 12000 its still not amazing reliability, of course its not just a straight comparison. But you get the jist
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Old 09-07-2012, 05:32 AM
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Ha at least u ain't building a top fuel dragster
Don't they get 30sec running time or something
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Old 09-07-2012, 05:46 AM
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Ha at least u ain't building a top fuel dragster
Don't they get 30sec running time or something
Ouch....Wouldnt be worth doing in my eyes haha
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Old 09-07-2012, 08:38 AM
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Originally Posted by anderkart View Post
Your mistaken, quite a few racekart engines will rev above 12,000 rpm, no problem.
The Tag Leopard go kart engine will easily rev to over 15,000.
Here's a link to the specs: http://www.remoracing.com.au/product...rillaleopardrl
LoL at comparing 2 stroke motors to 4 strokes
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Old 09-07-2012, 09:04 AM
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why would you want to go that fast
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Old 09-07-2012, 09:49 AM
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Originally Posted by scarletvw View Post
LoL at comparing 2 stroke motors to 4 strokes
Ok, fair enough smarty-pants... :rolleyes3:

The SwissAuto SA250, Tech F1 and Tech F1I are all go kart engines that rev to well over 12,000 rpm, and are 4-cycles:

More info about these kart engines here at this link:
http://www.ekartingnews.com/viewtopi...eb1d0bcc1cc25d





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Old 09-07-2012, 10:19 AM
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Quote:
Originally Posted by anderkart View Post
Ok, fair enough smarty-pants... :rolleyes3:

The SwissAuto SA250, Tech F1 and Tech F1I are all go kart engines that rev to well over 12,000 rpm, and are 4-cycles:

More info about these kart engines here at this link:
http://www.ekartingnews.com/viewtopi...eb1d0bcc1cc25d

Yup, and those engines are a lot closer to a race car engine then a honda GX 200 or predator or any other standard kart/industrial engine.

Our industrial engines are more akin to a standard car engine. Look at the regular ford motors, they are only made to put out so many RPM's, now look at one of the built race motors, they can put out the RPM's because they were designed to do so. The way that the honda engines and clones or even an old Briggs are designed they just cant handle the high RPM's that some people want.

And to quote from that link
Quote:
You just can't beat an engine with a pressurized oiling system, forged rod, light weight valve train and piston, proper angle for the intake and exhaust track. There is a reason for the cost difference besides the money exchange rate.
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Old 09-07-2012, 02:54 PM
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Quote:
Originally Posted by fowler View Post
Anything is possible with enough time and money

U could make these engines do 12000
When u are finished u would be left with a totally custom made engine with a redesigned lubrication system, water cooled, re bored/new block, internals with much closer tolerances and completely differant desingn and a new method of getting gasses in and out
This engine is related to the original by the coulings

anything is possible
But it is much easier to leave this to the big company's with all the technology and skills

EDIT
an F1 engine only runs for a few hours once a month or so then it is scraped at the end of the year
And to a point sports bikes only have a life of 5-10 years with a serious routine of services and looking after it

An industrial motor is designed to sit in a puddle on a building site and chug away for 20 years where people kick it to start it and a service is re filling the fuel tank
While a 12,000 rpm cement mixer engine would be awesome, that is not what I meant to imply. I was thinking of the many people who have extensive machine shops and a pile of titanium on hand. We see 'extreme' examples of engine modifications in other motorsport venues. I was wondering why there don't seem to be extreme examples here.
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Old 09-07-2012, 02:58 PM
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Quote:
Originally Posted by jman231994 View Post
To add to that, a F1 engine has to be heated to near running temperature before it can even be started, this involves running heated fluid through the engine. The tolerances are so tight that the engine practically wont start from cold...it would likely rip itself apart. And even with that the engines arent reliable at all if you compare them to a standard car engine.

From memory an F1 engine will usually go for about 2000km before being useless....maybe more, maybe less. Roughly 2000 though. By this point it has generally exploded, blown a crank, overheated, destroyed its bore etc. If you scale that down to 12000 its still not amazing reliability, of course its not just a straight comparison. But you get the jist
F1 engines also push the limits in terms of light weight and smallest physical size. I once had the opportunity to speak with Ron Dennis about how they work Mean Time to Failure (MTTF). He would not disclose much but the very little he did imply was fascinating.

My point is that given we know a little about F1 engines that spin 18,000, we should be able to create a one-lunger that goes 12,000 (or some other really round number).
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Old 09-07-2012, 03:00 PM
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why would you want to go that fast
Because we haven't.
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Old 09-07-2012, 03:02 PM
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Quote:
Originally Posted by anderkart View Post
Ok, fair enough smarty-pants... :rolleyes3:

The SwissAuto SA250, Tech F1 and Tech F1I are all go kart engines that rev to well over 12,000 rpm, and are 4-cycles:
Now we're cooking!
  #20  
Old 09-07-2012, 03:05 PM
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Quote:
Originally Posted by scarletvw View Post
Yup, and those engines are a lot closer to a race car engine then a honda GX 200 or predator or any other standard kart/industrial engine.

Our industrial engines are more akin to a standard car engine. Look at the regular ford motors, they are only made to put out so many RPM's, now look at one of the built race motors, they can put out the RPM's because they were designed to do so. The way that the honda engines and clones or even an old Briggs are designed they just cant handle the high RPM's that some people want.

And to quote from that link
I recall an article from Hot Rod (or a similar) magazine about how to build a 10,000 rpm SBC - 283 or smaller, as I recall.

I'm not as much talking about optimizing everything as is done on a purpose-built race motor as I am in the modifications that could take a stock-block (or near stock block) motor into the rpm stratosphere.
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