Project Fuel Injected Turbo FZR250, half

Intercooler in place. Kevin was kind enough to supply a lump of alloy to make the turbo-intercooler connection. It'll have a rubber hose joint to allow it to move around a bit. I'll probably make a new fuel tank to fit between the seat and the intercooler and there will be ducts to get cooling air to the intercooler in the front. They should fill in the gaps nicely

 

Very nearly finished with the flanges. Just need to drill the 2 holes in the flange to bolt to the turbo, left one. The other one will probably have a bit more machined off once I figure out how it's going to fit to the bottom of the intercooler core. Inside the turbo flange is 2.5° from about 5mm in through to the start of the other flange. Then the angle changes in 5° steps to 25°(per side) where it will open to the core. I'm not holding them together very well in the photo. When I do I can't see where they join. The OD where the connecting hose will be is 36mmOD

 

SIGH! It needs to be different. The turbo flange needs to change a bit and I'll make a new bit to weld to it. I also need a 45° elbow that I'll buy from Mikunioz which has a 34mm ID. I'll use the elbow as the way of making the connection when fitting the intercooler

 

A little bit early for the pool room. Now I've started thinking about the fuel tank. As usual there's far too many options - cut the existing tank and use just the back portion with the outlet on the bottom and the filler, or make a small alloy version, or try a fibreglass copy of the back section and glass in ally bits for the filler and outlets. I really don't want to cut a tank in half but it's looking like the sensible option. Plus, to add excitement to my life, I was thinking of cutting it with a cutoff disc without cleaning the tank. I'll video it for YT of course.

 

I've been working on the duct for cooling air to the intercooler. I've got the outside bits cut and bent and the main bit that forms the bottom of the duct. The last 2 bits are for the front bottom. Hopefully I'll sort that out tomorrow. Cardboard has been a blessing. Much easier to cut, shape, and start again when I screw up.

 

Progress with duct for cooling air to the intercooler. Luckily the worst of the welding is on the inside. I'm still thinking about how to secure it at the front. There's a few options but I might leave it for a bit.

A 45° elbow arrived from Mikunioz today so I can get back to making the connection from the turbo to the intercooler. I already have the tapered pipe designed and just need to spin it up using the lathe. As usual the plenum on that side will be mocked up using old cereal boxes.

 

Had a week in Sydney which was fun, mostly. After weeks of cutting, trimming, & restarting, I have more or less figured out how it's going to be between the turbo and the core. Miserable weather today is providing no motivation, hence me typing away on the PC and watching YT videos. It's hard to believe how long it's taken to come up with the shape of 2 little bits of aluminium. Hopefully it'll look pretty cool, and work, once I weld it together.

 

Sooo many weeks of work. Cutting cardboard templates, making alloy bits, throwing them in the bin, and finally getting something that looks like it might work. Yay . . .

 

Little bit of progress. Bits sort of sitting where they'll end up. Since this photo I have tacked the bits in place and given it a tap with the hammer. Access to one weld is going to be a bit of fun.

 

Intercooler finished and flushed out. apart from the welding it's turned out more or less how I wanted.

 

Put it together to see if it still fits and that I can actually install it without too much drama now that it's all together. It goes together fairly easily and the fuel lines snake through the gaps just right. The duct can be fitted with the intercooler in place. Quite pleased with how it came out. A little pit bike tank I have could fit without too much drama if I can't be bothered to make a nice one

 

The pit bike tank was a bit manky so I've started work on a nice alloy one. The rear curve is similar to a stock tank and it will slope forward at a similar angle. I have nearly finished the base, although I'm debating whether to mill ribs into the bottom. It'll look cool, not that you can see it, and will save a bit more weight. Kinda funny considering how heavy the bike is compared to other bikes in the class. I've made a rear mount which will bolt into the stock mount and 2 front supports from 5mm plate which will bolt into the 2 sub-frame bolts which I'll machine a flat into and then drill and tap. There was a couple of rubber grommet things which are perfect for the job.

 

Progress. The tank is together and mounts up without a problem. It feels just like the original tank when sitting on the bike. Just got a few pinholes to fix.

 

Took it to the track on Sunday. Sitting on it and riding it is exactly the same as having a standard tank. As for the intercooler , , what a difference. IAT has dropped from about 100°C to about 20°C which is huge. The bike now makes boost easily and quickly. With more than 10-12,000rpm the boost follows the throttle. Even backing off the throttle it maintains boost so clearly it is flowing a greater mass of air. Two problems though. 1 - the manifold pressure, MAP, oscillates. This is due to how I have the boost control working which results in a slight overshoot followed by an over-correction. This should be easy to fix. 2nd problem is that the AFR is very lean. With the reduced IAT the inlet air will be much denser and will require much more fuel. Initially I thought the ECU should have compensated but I think it might be just a bit too much. It shouldn't be a problem to fix. I suspect that the tuner will more or less ignore the main fuel table and add fuel using the 4D fuel table which is spanned with MAP and RPM. Fuel can be added dependent on boost and RPM. A section of the log display where the faults are obvious. The leanness is a good indicator of the increased mass of air entering the engine.

 

Not much to add apart from it has been back to my tuner. A bit of thought was given to how best to alter the tune and a little fuel was removed from the main map and a lot of fuel then added to the 4D fuel map to get the desired lambda on boost. With only 10lbs boost it made a bit more peak power as previously with 14lbs boost. We/He changed boost control for a steady 13 lbs boost.
As per the attached image the difference in the mid-range is impressive. The green line was photoshopped onto an image of 2 runs from this last session. The blue line is with 10lbs boost, the red line is 13lbs boost.
The green line equated to 30RWHP when tested on a dynojet. My calculations, I haven't tested it yet, suggest 33.5RWHP. The big thing is the gains through the mid range.
I'm pretty happy with this. The tune is still real conservative, although a few degrees of ignition timing was added it's still real safe. After I have a ride at the track I'll bump boost to 20psi at which point it should be approaching 40hp(or exploding).
A guy here in NZ, Glen Skachill, has built something similar. He's using a homemade ECU. Glen's a reasonably handy rider and I've put a link to a bit of on-board from Kaitoke kart track. It's worth a look. Glen thinks his bike is making horsepower in the mid-high40s.

 

Dyno runs. What happens is I start the run at about 8-9000rpm. Revs build to about 11,000rpm at which point the dyno applies load which it then varies to allow revs to increase at a designated rate. The dyno is configured for cars and the bike is only driving one roller, hence the inflated power numbers on the chart.