Sprintex?

Just wondering if any of you have had any experience with their superchargers?

http://www.sprintex.com.au/sprintex/

I had a look at their promo vid on youtube;

http://www.youtube.com/watch?feature=pl ... ijI_rVyms#!

Thoughts?

Steve

Neatest positive displacement SC I've seen on the market. Might have to add Comstock's EFI/ign. system to dial her in for legal level performance public use envelope. Here's one on V-Rod for size of install to keep in mind.

http://www.youtube.com/watch?v=zmojvwco ... ure=relmfu

Wow, thats one quiet spooling huffer, oh wait, it wasn't running - nevermind..
Has anyone seen one off a Mercury 4-stroke outboard used on a bike?

http://www.ebay.com.au/itm/AMR-500-...=AU_Car_Parts_Accessories&hash=item416cf37658

I just posted this link on another thread but it relates to this one too.

Steve,


I've emailed them with an interest, but no reply as yet. I read so many time that supercharger companies are notoriously difficult to get hold of. :shock:

I can understand in this modern world folks wanting to go down the EFI route. There doesn't seem to be much info on whether using a carb is a viable thing these days. :?

I've never dealt with a SC company but get the sense they mainly deal with dealer-installers not private one in a row customers, if they even sell direct to privates.
There must be some reasons we don't see many SC or turbo bikes on the road, beside just extra pricey and wearing on drive train and tires. One thing is what happens when the evil feeling part of you just wacks WOT before the thinking part of you has time to rationalize why not...

Positive pumpers have set ratio of boost through whole rpm range, top range is pretty easy but getting the bottom range to behave just off idle to legal speeds can be tricky. Draw though is easier to rig up than push though d/t pressure bleed issues in regular carbs. But the SC blends the mix rather well so generally are smooth runners across the whole band.

I guess you've already laid in bed awake on how to drive a SC, of any sort.

Hegel said:

Steve,


I've emailed them with an interest, but no reply as yet. I read so many time that supercharger companies are notoriously difficult to get hold of. :shock:?

Click to expand...

They probably are tired of getting email from people wanting to get more horsepower out of a 50 year old motorcycle engine when you can go down to the local Honyamsuskawi dealer and for half the cost of the superchager get a bike with twice as much hp.

I guess you've already laid in bed awake on how to drive a SC, of any sort.

Click to expand...

Yeah it's a head bender for sure. I keep toying with the idea of trying to rig something off the timing chest side, rather than go down the usual route of running a belt/s from the drive side. Pulley size is my biggest worry at the moment. I found a little spread sheet tool on their website for calculating pulley size, tho I'm not sure as yet if the answer it spat out is remotely correct. I'll have to look at the theory books again when I get a minute. Now they really bend my head out of shape. :shock:

I've already started making a 3d model, which will come together over the winter months. It's too cold in the shop now to work on anything, I know from experience that working with alley in near freezing conditions is not the smart thing to do, so the engines, etc are all packed in a coat of grease and will just have to wait till the spring.

Lol, Dave, I bet they get some laughs from the guys who want to bolt a charger to their lawn mower W.H.Y, asking how to do it.

Yeah man that lovely blank magneto drive area to tap for driving something has kept a generation or two restless as hell. Gear and pulley ratios can be figured by tooth count or by OD. Drouin's blowers are 7:1 via 7" crank pulley and 1" impeller pulley so @ 7000 rpm the impeller is @ 49,000. Compressors like this instant example are not turned as fast a a turbo fan though.

I'm just trying to remember how big a pulley I can fit in board of the timing chest, without hitting the fins on the barrels? 3-4"? Dunno I'll have to measure it again.

But yeah...It's just screaming to have something put in that space :mrgreen:

One of the reasons I like this unit is that you don't have to run it at some insane rpm to get a good boost gain, that and I wouldn't need to fit an intercooler...Which in my book is a show winner in itself!

'' Boost" is compressing the inlet air, & in the process it will get hot,but just how much so - depends on a number of factors, including pressure, ambient temp & etc.
Every complication can be countered by more complication however, so press on...& have a look at some of Hobot`s threads on charge density/cooling methods..

In horology (study of clocks), complication refers to any feature in a timepiece beyond the simple display of hours, ... Moreover, that a watch movement may be a Certified Chronometer does not itself count as a complication. The more complications in a watch, the more difficult it is to design, create, assemble, and repair.

Might work in a straight line , still pay to keep it simple ,

Or LIGHt , anyway . or itll wallow like an old honda . :wink:

The TS ain't very good area for a PTO for a hi rpm blower as its already geared down 1/2 crank speed and only about a 3" pulley could fit if centered as for magneto-points drive. I didn't notice if there's any transmission to raise drive rpm inside this instant compressor besides what hooks the screws to turn together. It might be possible to stick a jack shaft out the TS case to drive another bigger pulley to drive the compressor. I've seen alternators driven by thin belt pulley behind the main crank sprocket. Drouin 7" crank pulley is threaded so just replaces the long alternator rotor crank end nut. To drive Ms Peel's external alternator behind the barrels I'm going press a pulley on top run of the primary belt. Hopefully just friction for the 3/4 hp or so load but they make these belt in double sided teeth so a cog wheel could be engaged to drive the 5-10 hp this size compressor likely requires. I've also considered a friction wheel or belt toothed wheels placed against the front side of clutch basket. Don't know if this instant blower comes in cw or ccw spin or could be ordered either way.

Ugh, Good point to worry about detonation, which will definitely be way more prone to occur with a compressor than a blower as the compressor hits full boost ratio right off idle so the piston speed can't out run the pressure wave and piston spends more time at TDC to over heat the mixture to kaBooM. There are calculators that give estimates of boosted CR and fuel octane needs to keep spark timing at maxim torque pressure. 112 octane can work up to 16:1 effective CR or so. Water added at 15-20% of fuel mass can bring pump gas into 116 range plus the inter-cooling effect. When boost hits, extra fuel generally needed to richen up for detonation but can be replaced by water up to 50% instead of fuel and not put out the fire as much as extra fuel cooling method. This extra richness on demand is tricky to do with regular carbs so fuel injection is better - either by new school digital brain$ or old school gravity fed Lake type injector that's self compensating to air flow and air density like Mt to valley changes, so common in small aircraft.

Good points, have you checked out Gardner carbs, he started out doing H2O `ínjection' to counter the low octane 'pool' petrol in use in post war Britain.

I've only seen photo's of a few Gardner injectors and installs, like the Vincent side car land speeder, but they are very similar to Lake injectors which became Lectron which became QuikSilver, which Eldlebrock took over but no longer sells and barely supports for needles and such. These crude injectors can be made to work very well but its very tedious to configure them across full power band.

According to the tech bumf the max continuous rpm is 16000, which actually surprised me, when compared to other hi rpm chargers. Max boost is 2bar@that rpm.

If I can manage to squeeze a 90mm pulley inboard of the timing case + a 42mm on the charger it'd (according to the spreadsheet tool), give me an output rpm of 15000 @ 7000rpm engine speed. Not quite the full 2 bar, but close enough without any serious modifications. I've still got to work out if I need a snout on it, or not. But that'll come later.

Thanks J.A.W I'll do a search. In one of the books I bought it goes through the theory of CR / Octane, detonation and all that scary stuff. I'll do the search as there's no such thing as too much knowledge. Again according to the tech info(unless I've read it wrong), running the charger @ 1.4 bar the temp increase is only a few degrees 49-52ish?

I know int a lot of ways it'd make more sense to go the injector route...But I'd still like to try to go the old fashioned mechanical route, if that makes any sense? Am I right in thinking that reducing the CR also reduces the threat of detonation? Like I said I've got to do the homework again. I'm not trying to build a fire breathing drag strip monster as such, more something to use every day, but with some extra bite. Not really interested in a big top speed, just something that has interesting acceleration! :wink:

Hagel I think you are being a bit too risky trying to spin even this heat 'efficient' compressor much over 10-PSI in an iron barrel air cooled hot head Norton. I don't think you can fit a 90mm pulley in behind engine useless on end of a long shaft so the pulley lands in space between primary case and cradle OR stick it outboard on TS. If going over 10-ish PSI then you have to lower static & or effective CR or use super hi octane + inter cooling and maybe cabling head to cradle too like Peel.

Nortons are torque power not rpm horsepower design so I'm going the low boost Hi CR path which means building a dragster type cam engine that gives 7.5 effective CR at low rpm but then packs it in at mid range rpms when piston is moving fast enough to stifle detonation - up 6-7 PSI boost, then inject water for ~116 octane as CR spikes up towards 17-1 diesel range.

I'd had draster power on steet tire and garantee you will have to be VERY cautious learning handling loose as goose handling on rear tire only. Like say you give some throttle while tipping out of lane to pass a line of cars and truck in a flash, you can easy end up flat tracker wide lazy crossed up slide off far edge. I do have some fear for you as I only lucked out to survive my lesions early on and definitely retain that fear on what Peel will deliver.

Think about cryogenic tempering and various ceramic and thermal coatings and Singh Grooves or good squish band closeness, which also limits rpm to clash. Also lowering the front to stifle too easy wheelies.

Here's some calculators to entertain and train.

https://www.google.com/#hl=en&output=se ... =p&pdl=300

Hegel said:

According to the tech bumf the max continuous rpm is 16000, which actually surprised me, when compared to other hi rpm chargers. Max boost is 2bar@that rpm.

If I can manage to squeeze a 90mm pulley inboard of the timing case + a 42mm on the charger it'd (according to the spreadsheet tool), give me an output rpm of 15000 @ 7000rpm engine speed. Not quite the full 2 bar, but close enough without any serious modifications. I've still got to work out if I need a snout on it, or not. But that'll come later.

Thanks J.A.W I'll do a search. In one of the books I bought it goes through the theory of CR / Octane, detonation and all that scary stuff. I'll do the search as there's no such thing as too much knowledge. Again according to the tech info(unless I've read it wrong), running the charger @ 1.4 bar the temp increase is only a few degrees 49-52ish?

I know int a lot of ways it'd make more sense to go the injector route...But I'd still like to try to go the old fashioned mechanical route, if that makes any sense? Am I right in thinking that reducing the CR also reduces the threat of detonation? Like I said I've got to do the homework again. I'm not trying to build a fire breathing drag strip monster as such, more something to use every day, but with some extra bite. Not really interested in a big top speed, just something that has interesting acceleration! :wink:

Click to expand...

2 bar??? 2 bar boost, i.e. 3 bar absolute pressure (1 bar atmospheric plus 2 bar boost) is way more than you can expect a Commando to handle. That's 29 psi boost in old money. Typical street supercharger applications for air cooled engines like the Commando are 5 to 10 psi (0.2 to 0.4 bar), and that's still pushing it with stock CR and pump gas. Am I missing something here (it's been known to happen before)?

Ken

Okay, I think I see the problem here. Looking at the Sprintex specs, what they are giving you is absolute output pressure, not boost (relative pressure). When their chart shows 2 bar absolute pressure, that's 1 bar relative, so the max boost they specify for the 150 unit is 1 bar, or 14.5 psi. That's still too much for a stock CR Commando street bike to try to live with. Like hobot said, you might make it work well with half that much boost.

Ken

The breaking point of boosting a stock engine with simple draw though carb or mechanical injector d/t detonation and fueling and heating issues occurs about 10 PSI boost and reason Drouin mostly limited to this in 750's size street engines. Over 10 PSI all kinds of things must be done to survive it or just get it to run worth a dam.

I'm not sure how the positive screw type displacement compressors boost curve works out, just that they always provide a set ratio of boost say 14 PSI over ambient while a centrifugal blower is at low or no boost on light throttle but can be spiked above its rated boost like Tom Drouin and Bruce MacGregor report - spiking boost over 12 PSI on 850 stocker. Up to 5-6 PSI boost on stock Norton is just like being on cam good w/o much worry to blow up. Issues begin showing up just over this boost level on stockers. Drouins run 5-6 lb boost showing at highway cruise speeds I"m told.

If I was to design my own supercharger I'd go with the blower end of a modern turbo to belt drive somehow by pully on crank or cog on primary belt-chain run.