Clutch Spring Stiffness

[VenturiSection]

Does anyone know the clutch spring stiffness for a 2006 FZ6 Fazer.

I'm currently involved in building a formula student vehicle that runs a Fazer engine with a supercharger. It produces around 80hp and over 100Nm of torque. Low horsepower due to use of 19mm restrictor. The engine is also running on ethanol. The throttle has to be upstream of the restrictor which means the engine has to be remapped etc.

The plenum needs a backfire pressure release valve as we're in the phase of trying to tune it and sort out the ignition timing and I'm trying to find out if we can use the clutch springs from a different engine we have lying around to make a pressure release valve.

you can check out the project here:

Chalmers Formula Student

we aim to be running a carbon intake with intercooler cores asap as our intake temps otherwise are in the region of 125 degrees so our old car had some cooling issues.

Any help would be greatly appreciated! and i'll put a mention in the next newsletter we do to all our sponsors


or if anyone has any other ideas what to use instead of this spring that i can rip from a damaged motor we have! All responses are welcome!

 

[madmanmaigret]

could you use something along the line of a turbo waste gate? what psi are we trying to bleed? is this in a high temp application? I dont know the spring rate for the clutch springs but it seems they would be pretty stiff.

p.s. car looks really cool. is volvo a sponsor?

 

[HavBlue]

Go down to the local speed shop and get a pop off valve for a blower. That will do exactly what you want.

 

[VenturiSection]

the car pictured is last years one we're busy at work with this years.

Pop off valves are one of my initial ideas but thats more of a temporary solution and the next problem is that because the throttle is upstream of the restrictor the engine will go on full throttle-supercharger input. its a good idea though. I was thinking of using a radiator cap which is a bit colin chapman.

Its not for pressure created by the supercharger its if there is a backfire into the plenum during overlap or whatever as we haven't set the engine up properly yet and we had a backfire yesterday that sent the plenum flying. at least this year we managed to avoid denting the ceiling.

I also added the loverly complication of dry sumping this years stuff so we have loads to do still.

Volvo is a sponsor of ours - we have quite a list of sponsors.:thumbup:

 

[HavBlue]

the car pictured is last years one we're busy at work with this years.

Pop off valves are one of my initial ideas but thats more of a temporary solution and the next problem is that because the throttle is upstream of the restrictor the engine will go on full throttle-supercharger input. its a good idea though. I was thinking of using a radiator cap which is a bit colin chapman.

Its not for pressure created by the supercharger its if there is a backfire into the plenum during overlap or whatever as we haven't set the engine up properly yet and we had a backfire yesterday that sent the plenum flying. at least this year we managed to avoid denting the ceiling.

I also added the loverly complication of dry sumping this years stuff so we have loads to do still.

Volvo is a sponsor of ours - we have quite a list of sponsors.:thumbup:

Isn't the whole idea to prevent the pressure in the plenum from exceeding a specific level? The reason street cars will use the pop off valve on a blower is the same as it is the backfire that launches that blower; hence the reason for straps on competition cars. In this case you are simply placing it further down stream. The effect should be the same.

 

[VenturiSection]

Isn't the whole idea to prevent the pressure in the plenum from exceeding a specific level? The reason street cars will use the pop off valve on a blower is the same as it is the backfire that launches that blower; hence the reason for straps on competition cars. In this case you are simply placing it further down stream. The effect should be the same.

our throttle body is upstream of the plenum and we don't want to run with a pop off valve in competition because that means the end of the race.

 

[HavBlue]

our throttle body is upstream of the plenum and we don't want to run with a pop off valve in competition because that means the end of the race.

Yesterday you said the plenum went flying (assuming this means it blew off the mount) so it is understood the pressure inside the plenum got to the point it could overcome the bolts mounting it down. Would it not then be prudent to limit the pressure at that point? Doesn't matter where the throttle body is. What matters is where the pressure develops and what you want to limit it to.

 

[madmanmaigret]

is a pop off valve the same or similar to a blow off valve used in turbo'd engines? or totally different? is there some way to limit the backfires?

 

[VenturiSection]

Yesterday you said the plenum went flying (assuming this means it blew off the mount) so it is understood the pressure inside the plenum got to the point it could overcome the bolts mounting it down. Would it not then be prudent to limit the pressure at that point? Doesn't matter where the throttle body is. What matters is where the pressure develops and what you want to limit it to.

What are you trying to say. I really really don't understand

 

[VenturiSection]

is a pop off valve the same or similar to a blow off valve used in turbo'd engines? or totally different? is there some way to limit the backfires?

When the engine is properly tuned we might be able to limit back fires. As it is its not set up yet.

Pop off valves pop off and you need to reset it. meaning we can't use one as the engine will then go on full throttle as the valve will be open.

This is not a solution we can use.

And i wouldn't bother with a pop off valve i'd just use a radiator cap as its cheaper.

 

[HavBlue]

What are you trying to say. I really really don't understand

At issue is a positive pressure differential. Under normal characteristics the airflow is a downstream flow however, when that engine backfires it is creating an upstream positive pressure increase within the plenum with a magnitude great enough to blow that plenum right off the mounting boss. This in effect is the same condition which occurs when the 6, 8 or 1071 blower decides to launch itself right off the intake manifold when you are overdriving the blower and that engine backfires hence the reason for the pop-off valve. So, the corrective action would be to (A) alter the run profile reducing the possibilities for that backfire and (B) determine where the greatest pressure increase occurs so a pop off valve can be installed to bleed off that positive pressure. Now, there are any number of specifically rated valves available right down to those used on the air compressor you may have in your home garage. What we need to know is how much pressure we are talking about. If we don't know what kind of pressure we are dealing with how can we know what rating we are looking for?

 

[madmanmaigret]

When the engine is properly tuned we might be able to limit back fires. As it is its not set up yet.

Pop off valves pop off and you need to reset it. meaning we can't use one as the engine will then go on full throttle as the valve will be open.

so is the pressure to high for a blow off valve in a turbo system? They will reset themselves after the pressue goes back down.

 

[Hellgate]

Man, I'm confused...:surrender:

Here's a link to a place in the UK who is putting blowers on Hayabusa engines for some kind of a Formula car. Maybe you could contact them and see what they are doing? Because its an inline four, I'd guess your plumbing would be similar.

Afterall, why reinvent the wheel when someone else already has a nice wheel?

Suzuki Hayabusa Car Supercharger Suzuki Hayabusa Car Superch

 

[grommit]

Man, I'm confused...:surrender:

Here's a link to a place in the UK who is putting blowers on Hayabusa engines for some kind of a Formula car. Maybe you could contact them and see what they are doing? Because its an inline four, I'd guess your plumbing would be similar.

Afterall, why reinvent the wheel when someone else already has a nice wheel?

Suzuki Hayabusa Car Supercharger Suzuki Hayabusa Car Superch

They do FZ6s as well, not shown on the website, but they had an ebay entry for some time, not working now thou.

http://www.600riders.com/forum/fz6-mods/1319-super.html

 

[madmanmaigret]

seems that with the efficiency of turbos, superchargers would be obsolete on anything this small.

 

[Hellgate]

seems that with the efficiency of turbos, superchargers would be obsolete on anything this small.

Good point, simpler and lighter too.

The GPz Turbo 750 was an amazing bike in it's day. Talk about FAST! When it was on boost it hit so hard. Off boost if was a dog. It had a little, tiny turbo, but man it hit.

I've always kept my eyes open for one of those. All that I've seen are all totally flogged and completely worn out.

 

[HavBlue]

seems that with the efficiency of turbos, superchargers would be obsolete on anything this small.

The turbo guys would like to think so and while they are more efficient, that hairdryer will never be as easy to modify or produce the all out horsepower associated with a huffer. Now, the diesel guys have it both ways and have for years while using both the hairdryer and huffer on the same engine for industrial applications like that of oil well skids.

As to pop off valves needing to be reset, only some do while others are auto reset.

 

[madmanmaigret]

that hairdryer will never be as easy to modify or produce the all out horsepower associated with a huffer.

changing pulleys FTW!

 

[HavBlue]

changing pulleys FTW!

Yeah, just carry a few different pulleys and like Burger king says, have it your way.....

 

[madmanmaigret]

Yeah, just carry a few different pulleys and like Burger king says, have it your way.....

...and such linear power delivery.