#6

[pete376403]

Would this be any use? Controls the pump so a return is not required. May not meet your requirement of rising pressure with boost
https://www.madhu.com/content/Main/FuelPumpController

[speedpro]

Good feedback and suggestions, thanks. Adding a vent to the surge tank seems like a good idea and I'm part way through doing just that. Cooling the fuel or at least reducing the variation in temperature also seems like it's worth looking at. I don't feel like making another surge tank with baffles between the return line and the pump supply line. Another option could be to pipe the return line into the main fuel tank. Fuel sucked out of the surge tank would be replenished by the normal fuel line from the main tank and the return fuel could be fed into the main tank in any place. I actually have a bolt on fitting with two pipes out the bottom. On the inside of this fitting one outlet has an extension tube. This connection could be used for the return putting the bubbles in the returning fuel above the outlet to the surge tank, or I could simply fit another fitting to the tank and connect the return line to that. This would increase the mass of fuel absorbing the injector heat, rather than only the small amount of fuel in the surge tank, plus increase the area radiating any heat which also would not be behind the hot engine. I'd have to make sure that the fuel line from the main tank to the surge tank flowed more than the pump was sucking out or it would simply draw down the fuel level.

The bottom of the tank already has a layer of foam rubber. I wonder if that was to keep engine heat away from the fuel?

[speedpro]

I have been thinking about engines and rod length ratios and so on.

What I wonder about is if there is a better velocity profile for a piston when it comes to extracting the maximum power from the fuel/air combustion. Currently the piston velocity varies at a more or less sinusoidal rate. Would there be any benefit to having the piston move at a different velocity at various points around TDC and ignition. Could more power be extracted if the piston moved at a slower pace after ignition and accelerated at a slower rate or would faster be better?

I'm not asking how it would be achieved although I have been thinking about how it might be done. I am interested in the theory of extracting power from fuel and air as it combusts and how that would most efficiently be done using a piston whose speed could be altered from the current piston speed at the same RPM.

[F5 Dave]

Start by asking how much friction would be added to such a bottom end beyond the plain or roller bearing crank, and what happens to the heat, and what happens if it can't keep up.

[husaberg]

I have been thinking about engines and rod length ratios and so on.

What I wonder about is if there is a better velocity profile for a piston when it comes to extracting the maximum power from the fuel/air combustion. Currently the piston velocity varies at a more or less sinusoidal rate. Would there be any benefit to having the piston move at a different velocity at various points around TDC and ignition. Could more power be extracted if the piston moved at a slower pace after ignition and accelerated at a slower rate or would faster be better?

I'm not asking how it would be achieved although I have been thinking about how it might be done. I am interested in the theory of extracting power from fuel and air as it combusts and how that would most efficiently be done using a piston whose speed could be altered from the current piston speed at the same RPM.

Generally Formula 1 and motorcycle engines - have rod ratios of more than 2:1.
Honda know this but their street engines but for economy tend to have much shorter rod ratios this maybe to saver materials in engine parts and blocks.

With the dwell you gain in one area but lose in another.
Your FZr has two rod lengths used in the two main models the difference being made up not in the deck height but in the piston deck height
With the the pistons design as far as i know, the closer the ring is to the top the more power it makes.
but the more heat it is exposed to so in your case with a turbo will this extra heat rings be worth it?

[speedpro]

This is nothing to do with the FZR. Just a new thought.

[speedpro]

Been tidying up the exhaust system for my FZR. Once I get the fuel map where I want it this lot will go back on. There's still a new piece needs to be made for the intake plenum to connect to the turbo. I have a few plans for the intake and have cut the plenum inlet and mounted a flange. There is a longer term plan to remake the exhaust manifold and to relocate the turbo directly in front of cylinders 3 & 4. In the meantime I'll probably run this system and properly set the paint and then wrap the exhaust to trap the heat to aid with maintaining the gas volume between exhaust port and turbo. EDIT: the turbo tailpipe isn't tapered. It just looks that way in the photo. Plus I still have work to do on the tailpipe to plumb in the wastegate outlet.

[speedpro]

Done a bit more painting, this time it's the intake plenum. This afternoon I also made an alloy adapter that bolts on the plenum and connects the hose from the turbo. It took way longer than expected but there was a bit more to machining it than I thought. Thanks to Kevin at Motorcad for showing me. Just need holes for the mounting bolts and it'll be finished

[speedpro]

Bolted together. After a bit of tuning tomorrow it will be installed with the turbo and then things will start getting serious. 40hp would bring a smile to my face.

[F5 Dave]

That's for pussies. Turn the pressure up until it blows, then rebuild the other side.

And obviously try just a little bit more. Just a smidge.

[speedpro]

Had an enjoyable and successful afternoon at ESE with the FZR on the dyno. I was doing runs at various throttle settings and logging the AFR so adjustments could be made to the fuel map. I made up a "desired lambda" table and the ECU can do a comparison of "desired" and "actual" lambda and also calculate what adjustment is required to make them match at every TPS position and RPM point. You only have to hold the throttle position and let the motor rev through the region of the fuel map you are tuning.

It's not perfect but does work very well.

One reason I wanted to do this all again is that last time resulted in a peaky looking fuel map. What I expected was a progressive change in values. I was very careful today to concentrate on the locations that had peak values with lower values each side.

The outcome was a fuel map with a ridge of peak values at 7000rpm and another ridge of peak values at approx 14,000rpm and partly into 15,000rpm. It doesn't seem to be an error as I went over it more than once.

I suspect it might have something to do with peak power supposedly being at 14,000rpm in standard trim. If this is correct it does highlight the compromises made using carburetors which will be incapable of fuel delivery with the peaks and troughs.

The attached table has the peaks highlighted. In the graphical version of the table it is REALLY obvious.

[speedpro]

Here's a sample mixture map. The squares are highlighted in red-green depending on how far away from the desired value the actual logged value is. The light blue highlight cells are ones I have double clicked to update the fuel map.

[TZ350]

.
The maps are very interesting. I am looking forward to the dyno results with turbocharging.

[Grumph]

The outcome was a fuel map with a ridge of peak values at 7000rpm and another ridge of peak values at approx 14,000rpm and partly into 15,000rpm. It doesn't seem to be an error as I went over it more than once.

I suspect it might have something to do with peak power supposedly being at 14,000rpm in standard trim. If this is correct it does highlight the compromises made using carburetors which will be incapable of fuel delivery with the peaks and troughs.

The attached table has the peaks highlighted. In the graphical version of the table it is REALLY obvious.

Historically, Yamaha have got round the mixture peaks and troughs by tweaking the ignition advance curve. Too rich at one point and can't change it ? - Add advance. Lean - retard at that point.
The ignition curves for the five valvers show this up perfectly.

[speedpro]

Spent time dummying up the turbo install today. Getting the turbo back together with the bits lined up relative to each other and fitted back on the bike was a mission but I'm there now. The electric waterpump is going to need a new home, or I'll need to change a few things with the turbo compressor inlet and airfilter. There also a little boost control valve that is going to need a home. I forgot how tight a fit the turbo is in the bike and to the engine. Maybe it's a good time to relocate it to the front of the engine but that brings it's own set of problems.

My wife asked why I do it. She doesn't understand these things.