bi22le
|
| posted on 11/7/11 at 08:42 PM |
|
|
Home made supercharger?
Hi all,
I was day dreaming the other day again about supercharging my car and had a look for Rotrex superchargers, they cost soooo much!
You can get a MINI Eaton supercharger for a fifth of the price but it wont fit in a 7 as far as I know. I dont think there is room in my Striker
anyway!!
So, after looking at a Rotrex and speaking to my mad mate (bending and building a bonkers V8 MG Midget from scratch) it was thought as possible.
Could I not get a small ish turbo, split it and pulley the shaft?
A machined plate may need to be made up so the oil cooled bearings dont melt and internals are weighted, supported correctly?
10 to 1 ratio pulley.
. . . . . . . I dont know, I was just dreaming.
Thoughts, experience?
Happy driving all,
Biz
Track days ARE the best thing since sliced bread, until I get a supercharger that is!
Please read my ring story:
http://www.locostbuilders.co.uk/forum/13/viewthread.php?tid=139152&page=1
Me doing a sub 56sec lap around Brands Indy. I need a geo set up! http://www.youtube.com/watch?v=EHksfvIGB3I
|
|
|
|
|
tomgregory2000
|
| posted on 11/7/11 at 08:46 PM |
|
|
I dont think you will be able to spin it fast enough, simple as that
|
|
|
clairetoo
|
| posted on 11/7/11 at 08:48 PM |
|
|
In a word - no .
The Rotrex has an epicyclic gearbox , which increases the revs so the pulley can turn at a reasonable speed - even multi V pulleys cant run at 60000
rpm...............
[Edited on 11/7/11 by clairetoo]
Its cuz I is blond , innit
Claire xx
Will weld for food......
|
|
|
daviep
|
| posted on 11/7/11 at 08:55 PM |
|
|
I think the pulley ratios would be prohibitive, I think you'd need at least 20:1 you're looking for turbine speeds of about 100,000rpm,
which mean having a crank pulley bigger than 2 foot diameter.
Davie
“A truly great library contains something in it to offend everyone.”
|
|
|
bi22le
|
| posted on 11/7/11 at 08:58 PM |
|
|
Ah nuts.
any alturnatives to rotrex or a method of skrinking an eaton?!?
Track days ARE the best thing since sliced bread, until I get a supercharger that is!
Please read my ring story:
http://www.locostbuilders.co.uk/forum/13/viewthread.php?tid=139152&page=1
Me doing a sub 56sec lap around Brands Indy. I need a geo set up! http://www.youtube.com/watch?v=EHksfvIGB3I
|
|
|
bi22le
|
| posted on 11/7/11 at 08:58 PM |
|
|
Ah nuts.
any alturnatives to rotrex or a method of skrinking an eaton?!?
Track days ARE the best thing since sliced bread, until I get a supercharger that is!
Please read my ring story:
http://www.locostbuilders.co.uk/forum/13/viewthread.php?tid=139152&page=1
Me doing a sub 56sec lap around Brands Indy. I need a geo set up! http://www.youtube.com/watch?v=EHksfvIGB3I
|
|
|
tomgregory2000
|
| posted on 11/7/11 at 09:03 PM |
|
|
Just use the turbo as it was intended!!!!!!
You know you want to 
|
|
|
MikeRJ
|
| posted on 11/7/11 at 09:03 PM |
|
|
quote:
Originally posted by bi22le
Could I not get a small ish turbo, split it and pulley the shaft?
Certainly, but you'd need the budget to develop a suitable gearbox and solve all the lubrication issues. I doubt that it would be cheaper than
buying a Rotrex...
|
|
|
balidey
|
| posted on 11/7/11 at 09:24 PM |
|
|
Why can't you do it? I looked into this a while ago for my cinquecento, very small engine, very small engine bay.
A Rotrex is just a turbo housing on the side of a bespoke made gearbox.
As for speeds, I seem to remember from AG Bell's book on charging, a smaller turbo needs to run at faster speeds than a larger turbo, so if you
can't achieve the same speeds as a Rotrex unit just use a larger turbo running slower to achieve the same effect (OK, simplified it, but thats
basically the gist of it)
Ultimately you may not get it spinning at the same RPM, but you will still be achieving a positive pressure, so you will still have supercharged your
engine for a few hundred as opposed to a few thousand pounds. All you need to do is source or make the right gearbox. And as Rotrex have made one that
tells me there must be similar ones out there that you can adapt to do a similar job.
Dutch bears have terrible skin due to their clogged paws
|
|
|
zilspeed
|
| posted on 11/7/11 at 10:11 PM |
|
|
12V winches have planetary gears.
Not sure of the ratios though.
|
|
|
Badger_McLetcher
|
| posted on 11/7/11 at 10:27 PM |
|
|
To get up to those kind of speeds a suitable gearbox is needed. Get one and then yes, you could make yourself a a supercharger. Not entirely sure
where you could source such a beast though. It may be possible to make one yourself, dependent on your facilities.
If disfunction is a function, then I must be some kind of genius.
|
|
|
Doctor Derek Doctors
|
| posted on 11/7/11 at 10:37 PM |
|
|
Instead of gearing it up you could just use a much larger compressor. Something like an IHI 85mm truck turbo compressor would need to be spun less
quickly to to give the same flow than a tiny car turbo needing to pin at 80,000+ rpm.
But then again I think even with that size compressor you would need at least 30,000 rpm to get 10psi of boost. So you have a Turbo thats nearly a
foot accoss with a 1:5 (ish) pulley ratio to make a fairly low amount of boost.
You might as well just use a turbocharger, superchargers are a dieing technology, the manufacturers are selling them at a loss to the car makers and
they are less efficient, more complicated and make less boost. Turbos on the other hand are are getting, cheaper, smaller and more efficient.
Designer and Supplier of the T89 Designs - Single Seater Locost. Build you own Single Seater Racecar for ~£5k.
Plans and Drawings available, U2U or e-mail for details.
Available Now: The Sports Racer Add-On pack, Build a full bodied Sports Racer for Trackdays, Sprints and Racing.
www.t89.co.uk
www.racecarwings.co.uk
callan@t89.co.uk
|
NOTE:This user is registered as a LocostBuilders trader and may offer commercial services to other users
|
MikeRJ
|
| posted on 12/7/11 at 06:59 AM |
|
|
quote:
Originally posted by balidey
And as Rotrex have made one that tells me there must be similar ones out there that you can adapt to do a similar job.
The compressor is the trivial part of the Rotrex. The clever bit is the friction driven epicyclic gearbox which gives the massive gear ratio required
to spin the compressor at the required speeds, whilst taking the large peak torque during engine speed changes.
Simply fitting a pulley to an old turbo and hoping to be able to drive it fast enough is a total non-starter.
|
|
|
MikeRJ
|
| posted on 12/7/11 at 07:02 AM |
|
|
quote:
Originally posted by Doctor Derek Doctors
You might as well just use a turbocharger, superchargers are a dieing technology, the manufacturers are selling them at a loss to the car makers and
they are less efficient, more complicated and make less boost. Turbos on the other hand are are getting, cheaper, smaller and more efficient.
But still suffer from the same problems they always have, i.e. non-linear boost characteristics when they are working, and relatively high RPM
required to get them working in the first place unless you have the complexity of staged turbos etc.
|
|
|
bi22le
|
| posted on 12/7/11 at 09:29 AM |
|
|
Would it need to get to high RPM?
I only want a little boost, like 10psi or so. a big diesel compressor may do this.
a few have mensioned a massive pulley. is this to achieve tge possible required ratio needed and not due to torque required to spin the turbo?
I can get my hands pn a good condition massive boat engine turbo, garrett aswell i think.
Track days ARE the best thing since sliced bread, until I get a supercharger that is!
Please read my ring story:
http://www.locostbuilders.co.uk/forum/13/viewthread.php?tid=139152&page=1
Me doing a sub 56sec lap around Brands Indy. I need a geo set up! http://www.youtube.com/watch?v=EHksfvIGB3I
|
|
|
bi22le
|
| posted on 12/7/11 at 09:35 AM |
|
|
quote:
Originally posted by MikeRJ
quote:
Originally posted by Doctor Derek Doctors
You might as well just use a turbocharger, superchargers are a dieing technology, the manufacturers are selling them at a loss to the car makers and
they are less efficient, more complicated and make less boost. Turbos on the other hand are are getting, cheaper, smaller and more efficient.
But still suffer from the same problems they always have, i.e. non-linear boost characteristics when they are working, and relatively high RPM
required to get them working in the first place unless you have the complexity of staged turbos etc.
there are acouple of reasons why i want to avoid a turbo and this is one. power figers is appealing to me but i want good usable power in a light car.
a supercharger is better for this i feel.
the other reason is just to be different. although i would rather have a faster car and 4 figures of change than nothing!!
Track days ARE the best thing since sliced bread, until I get a supercharger that is!
Please read my ring story:
http://www.locostbuilders.co.uk/forum/13/viewthread.php?tid=139152&page=1
Me doing a sub 56sec lap around Brands Indy. I need a geo set up! http://www.youtube.com/watch?v=EHksfvIGB3I
|
|
|
nick205
|
| posted on 12/7/11 at 09:54 AM |
|
|
Didn't flak monkey use an Eaton charger on his GTS Duratec?
Might be worth looking at the install to see how he fitted it and whether a bit of imagination would see it in the Striker. There's nowt wrong
(IMHO) with having a charger poking out of the bonnet in a hot rod stylee 
|
|
|
daviep
|
| posted on 12/7/11 at 10:10 AM |
|
|
quote:
Originally posted by bi22le
Would it need to get to high RPM?
I only want a little boost, like 10psi or so. a big diesel compressor may do this.
a few have mensioned a massive pulley. is this to achieve tge possible required ratio needed and not due to torque required to spin the turbo?
I can get my hands pn a good condition massive boat engine turbo, garrett aswell i think.
You would need a huge pulley for two reasons:-
- The ratio, you need to be gearing up by a factor of around 10 or 20:1
- The pulley on the turbine has a minimum size depending on the belt used, it's not only the torque requirement but the minimum bending radius
of the belt.
I don't think a turbo turbine will have a linear output like a supercharger, I think you'll need to reach the correct operating speed.
Bolting on a huge turbo would seem counter productive to me, they aint going to be well packaged under the bonnet and it aint going to be light.
Davie
“A truly great library contains something in it to offend everyone.”
|
|
|
Doctor Derek Doctors
|
| posted on 12/7/11 at 12:33 PM |
|
|
quote:
Originally posted by MikeRJ
quote:
Originally posted by Doctor Derek Doctors
You might as well just use a turbocharger, superchargers are a dieing technology, the manufacturers are selling them at a loss to the car makers and
they are less efficient, more complicated and make less boost. Turbos on the other hand are are getting, cheaper, smaller and more efficient.
But still suffer from the same problems they always have, i.e. non-linear boost characteristics when they are working, and relatively high RPM
required to get them working in the first place unless you have the complexity of staged turbos etc.
At the end of the day though they're still a better solution, thats why more and more cars are turbocharged and less and less are supercharged.
Even the most somplex turbo's ar still simpler than a supercharger as well. Thats why the new forced induction F1 engines are all using Turbos
and not superchargers
Designer and Supplier of the T89 Designs - Single Seater Locost. Build you own Single Seater Racecar for ~£5k.
Plans and Drawings available, U2U or e-mail for details.
Available Now: The Sports Racer Add-On pack, Build a full bodied Sports Racer for Trackdays, Sprints and Racing.
www.t89.co.uk
www.racecarwings.co.uk
callan@t89.co.uk
|
NOTE:This user is registered as a LocostBuilders trader and may offer commercial services to other users
|
Toniq-r
|
| posted on 12/7/11 at 01:01 PM |
|
|
Well Im very happy with my SC fair it was not cheap but no complaints
|
|
|
flak monkey
|
| posted on 12/7/11 at 04:23 PM |
|
|
quote:
Originally posted by nick205
Didn't flak monkey use an Eaton charger on his GTS Duratec?
Might be worth looking at the install to see how he fitted it and whether a bit of imagination would see it in the Striker. There's nowt wrong
(IMHO) with having a charger poking out of the bonnet in a hot rod stylee
No I used a Rotrex.
A big compressor doesn't solve the problem, they just become very inefficient.
Either stick with a Rootes type charger, which are pretty simple to fit and set up, or shell out for a proper centrifugal one like the Rotrex.
The americans do produce some centrifugal superchargers with 20:1 step up belt drives, but none will produce very much boost and are very
inefficient....
Sera
http://www.motosera.com
|
|
|
Liam
|
| posted on 12/7/11 at 05:25 PM |
|
|
You can't just fit a truck turbo and run it slowly! It'll be so far away from anywhere on its compressor map it is actually intended to
operate it'll be next to useless.
|
|
|
ianjenn
|
| posted on 12/7/11 at 08:14 PM |
|
|
I have supercharged my kitcar with an Eaton M62, full details here with rolling road results and link to pictures
supercharging through bike carbs
[Edited on 12/7/11 by ianjenn]
|
|
|
madflow
|
| posted on 20/1/12 at 12:02 AM |
|
|
since im always interested in the unusual and homemade, this idea has me dreaming , have you seen the GATOR web site --they seem to make the idea of
belt driving the turbo possible, that is until you go futher into it --its an engineering exercise in bolt together components from your local bearing
supplier. more for show purposes than actual use , as i cant see those bearings taking the rpm and lack of oil feed for the turbo floating bearing
system.Still it does seem to have been done in the past and been made to work if only for limited period on short run time engines---not weekend use
even , let alone a daily driver .My next let down was calculation of cost , toting up the prices and its couple of hundred just in materials and
bearings , then add on machine costs so unless you can do machine/ lathe work your- self and get the bits for free or next to nothing , the eaton
45 or 62 unit is going to work out cheaper ( providing it not knackered) and at least give an almost guarenteed result of sorts. But this still hasn t
put me off the idea totally --bugger for self inflicted / time wasting/ money pit projects. cheers
|
|
|
spiderman
|
| posted on 20/1/12 at 01:29 AM |
|
|
I seem to remember that PPC magazine were doing a x/flow supercharged Westfield which was looking quite promising but as usual the articles stopped
before it was finished. Yet another unfinished project from the boys at PPC, I don't think I have seen a completed project of theirs yet,
perhaps they should have called it "Projects Permanently Ceased". 
Spider
|
|
|
