ZXR750 turbo conversion

[Mr Fro]

It'll all be worth it in the end!

 

It won't bring back my Allen key though.

[Hoggs]

Hoggfather lost an Allen key once. You guys should start a support group.

Sorry it didn't go great but you didn't explode so... win?

[Mr Fro]

Hoggfather lost an Allen key once. You guys should start a support group.

 

That's not a bad idea.

We had been together for... oooh... must be 15 years.

I'm more upset about losing that than [strikeout]some[/strikeout] [strikeout]most[/strikeout] all of my ex-girlfriends. Even the really dirty one who made superb sandwiches.

In other news, I've been reviewing the data from the ride and decided that dropping the float heights 2-3mm should help out a bit.

[JRH]

Hoggfather lost an Allen key once. You guys should start a support group.

 

That's not a bad idea.

I'm more upset about losing that Even the really dirty one who made superb sandwiches.

 

 

I didn't know allen keys could make sandwiches.

[Mr Fro]

I decided that using the fuel tank outlets for flow and return from the pump/regulator and therefore not having a reserve was pants. I want be able to use the reserve line as a reserve so added a dedicated regulator return line to the tank.

First off I drilled a hole in the tank:

Then I bent a bit of stainless pipe to exit the fuel somewhere near the filler point and machined down a pressure fitting to fit said pipe and accept the fuel hose:

 

Unfortunately, when I came to weld the two together the fitting that I thought was stainless steel fizzed, popped and melted so I had to remake it.

Plan B was to weld an M12 nut to the pipe and weld that assembly to the tank, then tap a thread on the fitting and use a hydraulic seal to stop it leaking.

Because I'd only emptied the tank in the morning I had to leave it out in the sun for a bit then purge it with Argon before and during welding to prevent explosions.

I also had the carbs off and reset the float height.

For some reason I can't quite fathom, everything is hunky-dorey when I test it on the bench but when I assemble it all on the bike the carbs start leaking.

If I ever do something like this again I'm going to use all new parts. I've wasted so much time chasing round fixing old stuff on this thing.

[bud]

Anything that starts off with "First off I drilled a hole in the tank" has my respect.

It's a great project and I'm sure you will get there I the end.

[oldgrump]

Hi, I take it you test Carbs on bench with the same pump you use on Bike? If using another pump. Maybe different pressures. Hence pushing fuel past Float Valves.

[Mr Fro]

Anything that starts off with "First off I drilled a hole in the tank" has my respect.

It's a great project and I'm sure you will get there I the end.

 

Thanks Bud. This is mainly driven by stupidity.

 

Hi, I take it you test Carbs on bench with the same pump you use on Bike? If using another pump. Maybe different pressures. Hence pushing fuel past Float Valves.

Yarp. It's variable pressure so I can fiddle it. Oddly, OEM pressure is 3psi and it leaked with 2psi... But only on the bike.

I'll take a look at it later in the week with any luck.

[Joeman]

Carbs at an angle when mounted to the bike..

Floats not floating enough? Need to bend the little tab a bit to make them close the valve more?

[Mr Fro]

Carbs at an angle when mounted to the bike..

Floats not floating enough? Need to bend the little tab a bit to make them close the valve more?

 

I test them at an angle and I nipped the floats down a couple of mm. The floats are floaty... I dunno but we shall see.

[leener]

This one has gone a bit quiet. I want to see the finished result

[Mr Fro]

This one has gone a bit quiet. I want to see the finished result

 

Yeah, I know. I've recently acquired a child which has bollocksed my free time.

I need to finish it up though as I'm using it as my uni project.

[leener]

Congrats, mate. Hope to see some new stuff on here soon. I always wanted to do this with my own bikes, but never had any time. Barely have time to fit heated grips.

[Westbeef]

Can you finish this yet ?

[Mr Fro]

Can you finish this yet ?

 

Oh, erm... yeah. Pretty much done.

It goes vooooom-tish and all that and it's been dynoed at ~170 bhp. I've still got work to do on the clocks and bodywork and I've got another turbo I want to try.

I'll bung up the dyno and some pics when I get a mo.

[Westbeef]

Can you finish this yet ?

 

Oh, erm... yeah. Pretty much done.

It goes vooooom-tish and all that and it's been dynoed at ~170 bhp. I've still got work to do on the clocks and bodywork and I've got another turbo I want to try.

I'll bung up the dyno and some pics when I get a mo.

 

Thank you

[Justarn]

Looking forward to that

[Mr Fro]

I realised that I posted pics of the bike a couple of pages back and I've not done anything about the bodywork since then.

Anyway, for the enjoyment of [mention]Westbeef[/mention] and anyone else who still looks at this thread, here's the final dyno readout:

 

I've not really ridden it what with kiddiwink and all that stuff but it goes quite well. The VNT turbo gives it a nice, smooth power delivery unlike a fixed geometry turbo (although I'm planning on sticking one on for shits&gigs) so it's just like riding a more powerful bike.

Time wise, it's taken the equivalent of 3 3/4 work weeks to complete and cost a smidge over £1.1k although that includes quite a few components bought in bulk but only a few were used and a few f**k ups along the way so probably £1k once those were taken out.

I really enjoyed the build but I doubt I'll get much time to use it.

[megawatt]

How much boost ya running?

[Westbeef]

I realised that I posted pics of the bike a couple of pages back and I've not done anything about the bodywork since then.

Anyway, for the enjoyment of @Westbeef and anyone else who still looks at this thread, here's the final dyno readout:

IMAG1266_1.jpg

I've not really ridden it what with kiddiwink and all that stuff but it goes quite well. The VNT turbo gives it a nice, smooth power delivery unlike a fixed geometry turbo (although I'm planning on sticking one on for shits&gigs) so it's just like riding a more powerful bike.

Time wise, it's taken the equivalent of 3 3/4 work weeks to complete and cost a smidge over £1.1k although that includes quite a few components bought in bulk but only a few were used and a few f**k ups along the way so probably £1k once those were taken out.

I really enjoyed the build but I doubt I'll get much time to use it.

 

That's impressive, do you know what it was making pre turbo? I guess you will have to give it me if you've got no use for it now

[Mr Fro]

I realised that I posted pics of the bike a couple of pages back and I've not done anything about the bodywork since then.

Anyway, for the enjoyment of @Westbeef and anyone else who still looks at this thread, here's the final dyno readout:

IMAG1266_1.jpg

I've not really ridden it what with kiddiwink and all that stuff but it goes quite well. The VNT turbo gives it a nice, smooth power delivery unlike a fixed geometry turbo (although I'm planning on sticking one on for shits&gigs) so it's just like riding a more powerful bike.

Time wise, it's taken the equivalent of 3 3/4 work weeks to complete and cost a smidge over £1.1k although that includes quite a few components bought in bulk but only a few were used and a few f**k ups along the way so probably £1k once those were taken out.

I really enjoyed the build but I doubt I'll get much time to use it.

 

That's impressive, do you know what it was making pre turbo? I guess you will have to give it me if you've got no use for it now

109 bhp - there's a dyno print on the first page or so.

I'll probably finish it up, use it for a bit then flog it on.

[mention]megawatt[/mention] - The boost gauge is only 1" diameter so the dyno guy couldn't get a good look during the runs - he reckoned it was about 0.7 bar though. I still need to finesse the boost regulation as it's a bit pants right now...

[megawatt]

That's nice n low, with stock pistons I wouldn't go higher. You need a bigger gauge and a reliable waste gate system. Also make sure you have very clean oil for turbo bearings.

[Mr Fro]

That's nice n low, with stock pistons I wouldn't go higher. You need a bigger gauge and a reliable waste gate system. Also make sure you have very clean oil for turbo bearings.

 

Yeah, that was the idea - to keep the engine as stock as possible. The only mod I've made to the engine is to lower the compression slightly to give a margin of error.

The "gating" is done with the turbine nozzles using a bit of a lash up by converting the old vacuum system to positive pressure. I need to play about with spring rates to get it right.

I'd really like an electric system driven by a servo motor - I think the ECU I have will do an on-off at x-boost. A servo that will survive close to the turbo and have enough torque is mo money though...

[megawatt]

I'd keep it as simple as possible, with maybe a back up electronic system. Maybe run a little bit retarded ignition timing.

A mate ran his race bike with a separate oil system and pump for the turbo, to keep the clutch crap away from the turbo bearings. Difficult on a road bike, but it's very easy to destroy a turbo engine.

[Justarn]

Maybe grab an old apexi avcr for boost control, fantastic once you get your head around em.