100cc forced induction F4 bucket. Anyone keen to have a real go?

[husaberg]

To save clogging other threads.

Speedpro made a start will anyone have a serious go

[Ocean1]

To save clogging other threads.

Speedpro made a start will anyone have a serious go

Not me, for the moment.

But collecting data against the possibility doesn't hurt...

All the calculations i was able to muster (Plenty) pointed to those to get the Hp i was aiming for.
The heat was the issue (these were i should say based on a Routes blower) which by nature of their design transfer a lot of heat if you can use a say screw or centrifugal blower yeah you can go higher for sure....
but the manner in which the there boast is delivered is much more problematic...... same as a Turbo scenario for instance
If anyone is dead serious i will see if i can retrieve them? maybe start a separate thread to stop clogging Mosseys.

I liked the wee Roots blowers on TM you linked to. Still pretty big but useable.

Heat is a result of compression, why would a Roots blower generate more heat than any other compressor design?

Another possibility is to use half a turbocharger, (the compressor) and belt drive it. There's far more available in the smaller sizes and they're less susceptable to wear so a 2nd hand item is more likely to be useable. Need an oil feed to bearings in either case.

I agree that the compression needs to be way down on that of a high performance NA engine, if you're looking to roughly double the output then you need 15psi boost. With allowable fuels and reasonably accurate ignition control I believe you'd get away with 8:1 without cooling. And there’s really no reason not to intercool it anyway, it’s not as if the engine is taking up an enormous amount of room.

As I mentioned, one possible source of dished forged pistons might be small diesels, even if the crown needed a little re-shaping there's far more material to work with and any normal diesel piston would cope with the load easily.

Oh, mention of Suzuki being chunky, or less well developed. Doesn't necessarily rule it out, the higher the pressure the less important is what would normally be considered essential flow characteristics.



And we got no bites with mention of a blown 2T?

[Kickaha]

To save clogging other threads.

Speedpro made a start will anyone have a serious go

His engine is to big and there's one already underway elsewhere

[TZ350]

And we got no bites with mention of a blown 2T?

It has been talked about but its not within the rules so no real incentive but there is a F5 2-stroke running nitrous up here, just for fun mind ...

If we were going to run a supercharged or turbo 4 stroke we would look at having a motive force (engine) just to drive the compressor as the rules don't say it must be turned by the prime mover. For a turbo we could look at cng/air for driving the exhaust impellor.

Blowing a 4 or 2 stroke with either compressor style we could use an inter cooler and pump up a large plenum to say 15psi and have it blow through a fuel injector body on the inlet.

[Drew]

It has been talked about but its not within the rules so no real incentive. There is a F5 2-stroke running nitrous up here, just for fun mind ...

No2 is the goods. One of the many positives, is that it cools the combustion chamber as it enters.

[Grumph]

Well I suppose as probably the only one on here who has actually built and road raced a supercharged bike, some words of experience may help someone...
Twins can be carburettored - singles can't. Inject singles if you do one. i'd link pressurised air to a relief valve to vent pressure when the throttle is shut on a single. Unneccessary on a multi.
Compression - we ran 9:1 on methanol and got away with it in a watercooled motor. Injected 9:1 should be possible on avgas, again watercooled head. as an aside, make the head joint dry, it's gonna walk around on the barrel whatever you do.Plenty of overlap on the cams helps too as the blow - through period cools valves off and doesn't sacrifice power. We started out at 18ib boost and found even on meth the charge heating from churning in a rootes blower (answer you question Husa ?) was such that the rotors picked up on the end plates. Enough clearance dropped boost to 15lb - which was penty.
I've looked in passing at car air con compressors - compact and designed to accept revs - but heavy....
Weight is always the tradeoff. We finished up with an F3 bike making well over 100 rwhp but weighing same as an F1...and with odd power characteristics. Steam engine torque which made a 6 speed box actually a penalty - 4 would have been about right.

Hope this helps someone

[Drew]

There's a wealth of knowledge someone should tap!

Problem with bucket blowing in the context of that f3 bike, is we're not allowed to run anything but pump gas. Adding more weight, but LPG is as good as we could get.

[koba]

Well I suppose as probably the only one on here who has actually built and road raced a supercharged bike, some words of experience may help someone...
Twins can be carburettored - singles can't. Inject singles if you do one. i'd link pressurised air to a relief valve to vent pressure when the throttle is shut on a single. Unneccessary on a multi.
Compression - we ran 9:1 on methanol and got away with it in a watercooled motor. Injected 9:1 should be possible on avgas, again watercooled head. as an aside, make the head joint dry, it's gonna walk around on the barrel whatever you do.Plenty of overlap on the cams helps too as the blow - through period cools valves off and doesn't sacrifice power. We started out at 18ib boost and found even on meth the charge heating from churning in a rootes blower (answer you question Husa ?) was such that the rotors picked up on the end plates. Enough clearance dropped boost to 15lb - which was penty.
I've looked in passing at car air con compressors - compact and designed to accept revs - but heavy....
Weight is always the tradeoff. We finished up with an F3 bike making well over 100 rwhp but weighing same as an F1...and with odd power characteristics. Steam engine torque which made a 6 speed box actually a penalty - 4 would have been about right.

Hope this helps someone

Cool!

Care to share more about this bike, it sounds interesting. Got any pictures?

[jasonu]

Weight is always the tradeoff. We finished up with an F3 bike making well over 100 rwhp but weighing same as an F1...and with odd power characteristics. S

Was this the brightly coloured GSXR400(I think) I saw at Pukehohe in the early 90's? I remember them having all sorts of electronic issues on the day.

[husaberg]

Not me, for the moment.

But collecting data against the possibility doesn't hurt...



I liked the wee Roots blowers on TM you linked to. Still pretty big but useable.

Heat is a result of compression, why would a Roots blower generate more heat than any other compressor design?

Another possibility is to use half a turbocharger, (the compressor) and belt drive it. There's far more available in the smaller sizes and they're less susceptable to wear so a 2nd hand item is more likely to be useable. Need an oil feed to bearings in either case.

I agree that the compression needs to be way down on that of a high performance NA engine, if you're looking to roughly double the output then you need 15psi boost. With allowable fuels and reasonably accurate ignition control I believe you'd get away with 8:1 without cooling. And there’s really no reason not to intercool it anyway, it’s not as if the engine is taking up an enormous amount of room.

As I mentioned, one possible source of dished forged pistons might be small diesels, even if the crown needed a little re-shaping there's far more material to work with and any normal diesel piston would cope with the load easily.

Oh, mention of Suzuki being chunky, or less well developed. Doesn't necessarily rule it out, the higher the pressure the less important is what would normally be considered essential flow characteristics.

The rootes heat the air more but vitue of its design i will post why later
the Assin 300 ids perfect size if run at half engine speed which is still within its reliable speed limits.
Re comp To make power boost boost and more boost
Diesel piston is a great idea but i never came accoss any but i didn't actually target them though
Arh yes... but you should start with a s few compromises as posible in my opinion anyway

His engine is to big and there's one already underway elsewhere

Only needs de-stroking, as does mine

No2 is the goods. One of the many positives, is that it cools the combustion chamber as it enters.

NO2 while great, is against the MNZ rules unfortunately.

Give us some more details Greg please.

PS is the turbo Atlas the guy From Turbo technology did still getting around CHCH?

[Grumph]

No pics ever taken sorry...never the same two outings running and i was too busy working on the thing to take pics anyway.

It was a 500 Kawa twin in a GSXR750J rolling chassis with 851 Duc seat and fairing of all things...actually looked quite good IMO. Royal blue. ChCh made Martin blower in prototype 750cc volume - only ever 2 made. Sidedraft dellorto twin choke with air cleaner rubbing the rear guard, 1250cc plenum chamber/manifold onto motor. Pipes almost rubbed front guard too....bulky.
Polyvee belt off LH end of crank - 1:1 with a tensioner pulley. Drive never gave any probs - up to 13 grand....
Marvics on loan from Kirby...and we used the 5.5 rear with an experimental soft slick ex Dunlop's Aussie testing programme...again through Kirby. Mal Campbell had found it too soft for the RC30 - just right for the F3.
Carburettored well - the big Dell was easy to set up. Odd feature, rev it on the stand and it would move forward. 2 X 2 inch pipes developed quite a sizeable amount of thrust. As raced, 15lb boost from just off idle to as far as we ever took it - 13 grand. I knew the guy who designed the Martin blowers and he was highly gratified at the flat delivery curve. He'd designed it with a turbulence reducing bar in entry and exit - reckoned it bench tested at better than 80% eficiency.
Head gasket probs killed it. i didn't mind the head and barel moving round on the cases but I couldn't keep the head to barel joint watertight. Ideally I'd have cast another barel with provision for meaty hollow studs joining head & barrel then the normal long bolts to the cases. Std barrel just didn't have the material there to do it. Dry decking anything is the way I'd go now.

We ran it at a puke national then changed it radically when we got home...any pics of it there would be gratefully received.

[Grumph]

PS is the turbo Atlas the guy From Turbo technology did still getting around CHCH?

Don't know - I've been told about it but not seen it. i did see what may have been an earlier version with a cabin blower.

Compression - in buckets you're talking (very) small bores which don't give the det problems of larger ones. we had a 74mm bore 4V/cyl head which wasn't as good as current 4V ones. Unblown we were running 40 deg plus advance and it needed about the same blown.
i'd estimate as said before that 9:1 is quite achievable on avgas even with around 12lb boost. A lot of the ignitions used now have det sensors anyway. Overlap as i said is a plus....too many people doing a blown motor look at the camming and say I don't want to waste any pressure...crap. Look at the post WW2 blown 1.5 Liter F1 motors. The Alfa 159 had a heap of overlap which the team described as the 5th stroke...rich alky mixture blown through the head cooled it enormously. 2 stage rootes blown straight 8 making around 450HP with only 2V heads. Still quite good but beaten on HP by the BRM V16....when it ran, but never on the track of course.

[speedpro]

I can relate to the head/cylinder joint problems. On my McIntosh I blocked off the oil galleries and supplied oil to the head galleries by external lines. I used copper gaskets with wire in grooves sitting just proud of the surface of the cylinders to form a mostly gas tight head gasket seal. Even with HT studs there was always evidence of minor leaks and movement. I also dropped the bore size to 72mm to leave just a little more meat in the sleeves and block which sorted out the reliability problems. With modern electronic engine management systems it'd be sweet if I ever get it going again. I have fired it up with a Haltech installed a long time ago but never rode it. The compression is about 8:1 and we've run it up to 18lbs boost but it cracked the #2 main bearing support part of the case. It did wheelie in "any" gear though. 12lbs seems a good boost figure. The motor still uses '73 Z1 cams but they have been degreed but there is still plenty of overlap. Heat was a huge problem. With bent exhaust valves it still made 175hp on the dyno.

[mossy1200]

Take a inline 4 , 400 and make 3 cylinders compress air into a collector and ram the last 100cc with unlimited oxy.

[husaberg]

Don't know - I've been told about it but not seen it. i did see what may have been an earlier version with a cabin blower.

Compression - in buckets you're talking (very) small bores which don't give the det problems of larger ones. we had a 74mm bore 4V/cyl head which wasn't as good as current 4V ones. Unblown we were running 40 deg plus advance and it needed about the same blown.
i'd estimate as said before that 9:1 is quite achievable on avgas even with around 12lb boost. A lot of the ignitions used now have det sensors anyway. Overlap as i said is a plus....too many people doing a blown motor look at the camming and say I don't want to waste any pressure...crap. Look at the post WW2 blown 1.5 Liter F1 motors. The Alfa 159 had a heap of overlap which the team described as the 5th stroke...rich alky mixture blown through the head cooled it enormously. 2 stage rootes blown straight 8 making around 450HP with only 2V heads. Still quite good but beaten on HP by the BRM V16....when it ran, but never on the track of course.

Fred Hicks built it nice job too very std looking with a link computer and a IHI of a Daihatsu (RB32)
i have an article here on it.
The beauty of using a FZR250 as a donor is that there are different std spec cams (3ln 2kr plus mix and match inlet ex)available
Also the worst thing you can do with a supercharged motor is give it insufficient cam duration on the exhaust because it has to breathe out all the mixture crammed into it under pressure. The victory library has excellent in depth article s that are basically a how to guide.
http://victorylibrary.com/supercharg...er-engine5.htm