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Turbocharging the CRF450
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Posted by: marshall5---------------------

I posted this in the wrong forum, so here it is again:

Ok folks, I'm going to perform a turbo install on my '02 CRF450, and possibly hillclimb with it. Although I'm very experienced with turbo setups on race cars (I own one), I haven't got much experience with bikes.

First off, what is the stock CRF motor capable of handling as far as power wise? I may do a 480-500 kit if forged internals are needed.

Also, I would need to fit an injection system with an airflow meter to keep air/fuel ratios correct, does anyone know what street bike has an EFI system that could be retro-fitted to the single cylinder CRF?

Lastly, can anyone direct me to a place specializing in custom fabrication that has good prices and does excellent work when it comes to custom piping and flanges?

Thanks.

Posted by: Rich Rohrich---------------------

Quote:

Originally Posted by marshall5

I posted this in the wrong forum, so here it is again:

Ok folks, I'm going to perform a turbo install on my '02 CRF450, and possibly hillclimb with it. Although I'm very experienced with turbo setups on race cars (I own one), I haven't got much experience with bikes.

First off, what is the stock CRF motor capable of handling as far as power wise?

The CRFs use a forged single compression ring slipper skirt that won't seal properly under the additional cylinder pressure. You are going to need to talk to JE or Ross about making you custom pistons with a different ring package and a totally reworked skirt design.

The oiling system doesn't have the capacity to handle the additional heat, and certainly not the capacity to supply the turbo center bearing if need be. A major rework of the oiling system would be in order. None of the current cam designs will work properly with a turbo either, so you'll need a custom grind from Webcam.

Quote:

Also, I would need to fit an injection system with an airflow meter to keep air/fuel ratios correct, does anyone know what street bike has an EFI system that could be retro-fitted to the single cylinder CRF?

You'd need to run a speed density system based on manifold absolute not mass air flow. None of the current street bike systems will be even close to workable but the F.A.S.T ECU could be adapted without too much work. Kinsler can supply a single barrel throttle body and RC Engineering can help with sizing a custom injector.

Quote:

Lastly, can anyone direct me to a place specializing in custom fabrication that has good prices and does excellent work when it comes to custom piping and flanges?

Thanks.

Talk to the folks at www.burnsstainless.com , they are real craftsmen and great to work with.

Posted by: Studboy---------------------

marshall,

While a real, working, turbo CRF450 would be awesome, do you really think that it would be worth the mucho time and money required to get it working? I'm thinking that a hillclimb modified CR500 or CR500AF would fit the ticket.

I'm not trying to put you off of your project or anything, but as Rich as layed out, it would be a really complex project. I would love to see it happen though.

Posted by: BradFrost---------------------

Yeah, sounds like a wicked project. Better buy some ear plugs for the infamous exploding head trick.

Posted by: marshall5---------------------

Rich that answer helped incredibly. I'll have to look into the FAST computer, I'm not too familiar with it. I forgot to mention that I'm going to convert it to an alcohol motor and possibly spray some N2O at it. Will the same companies still be able to supply the fuel components needed? Also, how would a Wiseco 500cc kit perform with a turbo? Or what about a 525cc stroker kit?

It would have been nice if I would have bought a Service Honda CR500AF and performed this project, but at this time that's not much of an option. Mainly because my bike is an '02 and would run me another $6k to upgrade bikes...unless of coarse someone out there wants to trade.

I'm really not stuck on the idea of using the 450 motor, but more or less anything I could wedge in the frame without going into too high of a price range at this point (don't know if a banshee motor would be possible). Does anyone happen to have measurements on a Banshee motor?

I felt the 450's style of power would give it awesome sandracing/hillclimbing potential, but maybe a two-stroke is the way to go.

I definitely appreciate any feedback from you all. Thanks.

Posted by: Studboy---------------------

marshall,

I would take the CRF450 motor ANY DAY over the banshee motor for hillclimbing, unless of course you are talking about one of the 540cc drag race banshee motors... in which case they are very fast, but VERY expensive. They would probably be too wide to stick in the frame without some serious widening, and there would be no place to put the pipes needed to make them run correctly.

Posted by: Rich Rohrich---------------------

Quote:

Originally Posted by marshall5

Rich that answer helped incredibly. I'll have to look into the FAST computer, I'm not too familiar with it.

http://www.fuelairspark.com/Technic...ems/Default.asp

Quote:

I forgot to mention that I'm going to convert it to an alcohol motor and possibly spray some N2O at it. Will the same companies still be able to supply the fuel components needed?

Yes.

Quote:

Also, how would a Wiseco 500cc kit perform with a turbo? Or what about a 525cc stroker kit?

They'll just be bigger versions of the initial problems.

Posted by: Green Horn---------------------

I know most of this stuff is way out of my league so I'll go easy on what I am thinking. How can a single cylinder motor operate a turbo? I was under the impression that it takes multiple cylinders to keep it spooled up and not lose rpm's? When the cylinder isn't going through the actual exhaust stroke, then what keeps the turbo spun up? On a mult-cylinder engine you have a more constant flow of exhaust flow to keep the turbo spun up, right? Granted the revolutions are quick, but I'd still think you'd see too much variance in the turbo rpm's. Forgive me if I have no idea what I am talking about and feel free to educate me.

Posted by: Rich Rohrich---------------------

In a case like this a turbo with a variable area turbine would likely be needed to keep things balanced. Something like the Garrett VNT (Variable Nozzle Turbocharger), but I haven't seen a compressor that was sized for anything as small as a 450cc engine.

Aerodyne had some really small variable area turbine models that people have adapted to sleds and lots of other small engines, but I'm unlcear on the status of the company and it's product at this point. I know Cujet put one of the Aerodyne models to great use on one of his projects.

Posted by: Green Horn---------------------

Quote:

Originally Posted by Rich Rohrich

Something like the Garrett VNT (Variable Nozzle Turbocharger

Which is why I tentavily posted.

Figgered there had to be something out there to avoid that problem.

Posted by: marshall5---------------------

I can't figure out how it would be possible to pump oil through the turbo bearings from the CRF motor. As far as cooling ability, a cooler could be added under the seat. I've also been thinking that another possible setup would be staged twin turbos. That setup would achieve max boost levels but may be far from possible. Does anyone know what the limits are of the stock cylinder as far as max bore size attainable before cooling issues? I would want to bump the cc's to the CRF's limit to attain better spool and boost characteristics, however stroking it will hurt the top end power I believe.

Posted by: Jasle---------------------

the Banshee motor is the same basic motor as the RZ350. So it fits in a bike.

Posted by: Rich Rohrich---------------------

Quote:

Originally Posted by marshall5

I can't figure out how it would be possible to pump oil through the turbo bearings from the CRF motor.

The OEM oiling system would never be able to handle feeding a turbo bearing. You'd need to use a sealed bearing style turbo.

Quote:

Originally Posted by marshall5

. I've also been thinking that another possible setup would be staged twin turbos. That setup would achieve max boost levels but may be far from possible.

You are only working with about 27-30 cubic inches so I wouldn't get my hopes up on this idea.

Quote:

Originally Posted by marshall5

Does anyone know what the limits are of the stock cylinder as far as max bore size attainable before cooling issues?

2mm is pushing it with a normally aspirated engine.

Posted by: flyinzuki---------------------

We have a KLR 650 with a turbo from a Diesel fork lift.
It's a tiny little turbo with no wastegate, we run the stock carb into it (draw through) on Methanol.
It is a blast...until the intake pops off and blows atomized methanol up your helmet

The motor is untouched and supplies oil to the turbo.

Posted by: marshall5---------------------

After a little research today I came to the conclusion that the only way I'm going to get to where I need to be is by putting in a different motor and taking advantage of an aluminum frame. If I pulled this off on the 450 motor in the end I'm still at a disadvantage to the 500 two-strokes being that they are lighter. I need to greatly up the power-to-weight ratio. I think I'm going to have to start thinking about possible powerplants which could somehow be wedged into the frame with minimal fabrication. I think it's all going to lead me to a Rotax motor. I've thought about using a large streetbike motor but an 800cc methanol-injected Rotax with a turbo seems like it would offer the most hp to weight. Not to mention it could climb some hills. Does anyone know where to find Rotax motors?

Posted by: xsnrg---------------------

A used CR500AF sounds like a good place to start...new they are $9k...I'd think by the time you sell a CRF450 and do all the mods you are talking about, you'll be a $9k and then some anyway, no? Unless your 450 is blown up or something and you couldn't get anything for it.

Posted by: marshall5---------------------

I'm guessing about $4-5k for what I want done on top of my bike. That would get me double the horsepower of a 500cc by using a Rotax 800cc twin. But there will be many big issues there. Drivetrain being number one. If I could find a used CR500AF I would very much consider it, thing is I can't find one. If anyone could help it would be greatly appreciated.

Posted by: xsnrg---------------------

Service Honda's website has one on there for $8200. What can you get for a '02 CRF450?

Posted by: techman---------------------

Flyinzuki,
I'd like to know more about your turbo KLR. Have you tested the hp, what about detonation, jetting changes at all, how much run time has it survived, etc
techman

Posted by: flyinzuki---------------------

The turbo KLR has 70 RWHP, but it wasn't running well that day.
Methanol was used because it was detonating @ 4-5 pounds of boost on pump 94.
Jetting... lets just say 1/8" was too big, main is .093"
The rings are shot from the methanol washing the oil away, we now use a top lube.
It has been running for less than 10 hours over the last year.
The chain used to get adjustments every 2000 miles, now it's every 2 miles.

The KLR has a roller bearing crank, I'm not sure what the new 450's have because I haven't been inside one yet.

Posted by: cujet---------------------

The Aerodyne turbo may still be around in a different form. Gerhard from Aerodyne now works for Bellintercoolers.com. Call there and ask for him. He can direct you to the current manufacturer.

By the way, they made aerodynes small enough to run on briggs and strattons. They also can mount in any position (as long as the internal setup is done first) and they hav self contained oil systems, not needing engine oil.

Chris

Posted by: nephron---------------------

Which would technically be more feasible, turbo or blower? Blow through belt-driven blowers are simple bolt-ons on V8's. Why not a bike? I have seen a VMax (and heard it

) with a crank-driven blower. Get yourself a piston with an inch-thick ringland, blow through the carb and inject nitrous into the intake....

Seriously, any blown smaller-engined dirtbike/motorcycle examples around? Somebody?

Posted by: Rich Rohrich---------------------

Quote:

Originally Posted by nephron

Seriously, any blown smaller-engined dirtbike/motorcycle examples around? Somebody?

SAE doc # 1999-01-3318
Title: Advanced super charge system for small engines
Publication Date: 09-01-1999
Author(s):

Shunzo Fujiwara Yamaha Motor Co., Ltd.
Nobuo Norimatsu Yamaha Motor Co., Ltd.
Jun Taue Yamaha Motor Co., Ltd.

Abstract:
The specific output of 4-cycle engines are generally smaller than that of 2-cycle engines. Increasing engine speed is one method to improve the specific output; however, it contains some disadvantages in application. Hence, improvement in torque with the 4-cycle engine is desirable. Although torque could be improved by supercharging, it seems difficult to apply existing systems for small displacement engines due to problems of their size and cost.

We have, therefore, newly developed a supercharging system named Advanced Crankcase Super Charge (hereinafter referred to as ACSC) using a crankcase as a supercharger. In this study, we made a 50 cc single-cylinder prototype engine with ACSC and carried out the engine unit tests and actual running tests on a scooter. From these tests, the torque that is twice as that of the naturally aspirated engine was obtained.

In addition, the driving performance equivalent to that of the vehicle with 2-cycle engine was achieved in the actual running test. It was also confirmed that the emission level was equivalent to that of a vehicle with a naturally aspirated engine. There was also an improvement in fuel consumption compared to the vehicle with 2-cycle engine.

Posted by: SFO---------------------

I used to have the dirtbike article where Donny Emler built a crancase supercharged xr-100. It was on a case reed kx-80 bottom end using reed valves on both sides of the cases to pump a plenum with variable volume.
I never saw it again so I assume it wasn't sorted.
On draw through turbo systems we would run a plate between the carb and turbo with the nitrous nozzles. Burping the no2 would help spool the turbo up off the line.

Posted by: flyinzuki---------------------

How about a blown Hyabusa that runs 8.20
FMS Blower
You can get a smaller blower for about $1,700 - $1,800.
It will work in a draw through set up.
You will however, have to do alot of work to mount and tune.
The turbo would be easier no doubt.

Posted by: bikepilot---------------------

A while back there were reports of a turbo charged XR650R that was making 105hp at the rear wheel. I belive it was a swedish guy that built it. Might be worth a bit of searching.

have fun

Posted by: nephron---------------------

Quote:

On draw through turbo systems we would run a plate between the carb and turbo with the nitrous nozzles. Burping the no2 would help spool the turbo up off the line.

Stupid question...what type of bike, SFO?

Posted by: nsxxtreme---------------------

While not bike related you might look at the Honda jet ski. It's the only 4 stroke turbocharged jet ski made. Maybe look into how they accomplished it.

Posted by: SFO---------------------

Quote:

Originally Posted by nephron

Stupid question...what type of bike, SFO?

I don't remember the class, maybe pro/comp?
Draw through kit by Mr Turbo, gs1100/kz1000.

Posted by: DirtyDrew---------------------

What about the turbos and superchargers from waverunners? They seem more appropriately sized and designed for this application.

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Turbocharging the CRF450

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