Usually the stats are no-load speeds. But you are right, around here you never know what has already been tested. Looks like a 1:10 overdrive, or so? That is not too horrible to do, though it might be easier as a two-stage.
Usually the stats are no-load speeds. But you are right, around here you never know what has already been tested. Looks like a 1:10 overdrive, or so? That is not too horrible to do, though it might be easier as a two-stage.
Since durability is questionable on this idea we have over looked over volting the starter to increase rpms.
Dual batteries wired parallel to charge at 12 volts and a series connection to tap 24 volts driving the starter.
Longer recharge times but more stored energy available.
Curtis73 (Forum Supporter) said:Those pesky laws of physics :)
I agree. Energy isn't free. If you have a 60A motor to drive your supercharger and a 60A alternator, it will take about three seconds for your plan to generate zero additional power. Once you start drawing 60A and the alternator starts yanking 60A worth of power from the belt, you will have pretty much a zero net gain.
Yes, there is no free lunch. The comparison I made above was under the assumption that there is a stored up charge in the battery waiting to be used. This could come from regenerative braking, idling in grid, etc.
That said, it is theoretically possible for the above example you gave to still result in power gain because it allows for the introduction of additional fuel. It would be a horribly inefficient way of doing so though, vs just directly driving the supercharger.
Well, another way of storing large amounts of energy for short bursts is with springs. Another benefit is the energy stored in a spring is released with very low loss.
What about a garage door spring driven compressor?
I've thought about trying a garage door spring on the rear axle of a fwd car on a one way clutch... Would work sort of like a wind up toy car.
I mean, we're already deep into bad idea territory here might as well keep digging.
In reply to dean1484 :
I'm sorry but has no one considered the complexity of this idea?
engines don't run at a fixed. RPM. Thus required volume of air and fuel will vary broadly.
how are you going to tie all this together?
You want a simple and cheap momentary instant boost of power?
Use. NOX ! push the button and air and extra fuel is squirted in making more power.
light simple easy
Colin Wood said:So kind of like how Max could turn his supercharger on and off whenever he wanted?
I want to think that I read somewhere there was a Toyota that came supercharged from the factory that could be turned on and off by a switch.
The Toyota Previa is what you're thinking- the SC14 blower has an integral clutch to allow that and an 8.8:1 compression allowing the van to run without 91 octane. Here's Murilee Martin talking about it.
GIRTHQUAKE said:Colin Wood said:So kind of like how Max could turn his supercharger on and off whenever he wanted?
I want to think that I read somewhere there was a Toyota that came supercharged from the factory that could be turned on and off by a switch.
The Toyota Previa is what you're thinking- the SC14 blower has an integral clutch to allow that and an 8.8:1 compression allowing the van to run without 91 octane. Here's Murilee Martin talking about it.
The cool thing about these is they're an electronic clutch so yes, you can hook them to a switch. You can still find them in a lot of junkyards but they're notoriously difficult to remove.
In case it hasn't been said already (I could have missed it), using a starter for anything more than a couple seconds at a time will most likely make it fail drastically quicker than normal.
In reply to shagles :
I think there is an award for the most spectacular failure at the Challenge.
Another storage solution is super caps.
The mercedes amg superchargers use an electromagnetic clutch pulley as well, just in case the one from the Previa isn't up to the task. Run power to a dash switch and done. I'll let someone else figure out the retrofitting to whatever blower is to be used.
The garage door spring is a terrible, terrible, terrifying idea. But I want someone to try it, and post video, cuz I don't wanna be in range when it breaks. Was it Carlson who wrote a funny as hell story about a school bus with a massive spring on the rear axle that to this day I hope and pray was fictional?
There were WRC cars that solved turbo lag issues by hiding large air volumes in the intake tract that were pressurised by the turbo and then released back to the coldside when needed. What if you had a couple scuba tanks with solenoid valves that let you blast a whole buncha air at your intake when yawanna blow things up?
But rly the best way to do this push to pass button is to wire it up to a tank o' nitrous... ah well.
frenchyd said:In reply to dean1484 :
I'm sorry but has no one considered the complexity of this idea?
engines don't run at a fixed. RPM. Thus required volume of air and fuel will vary broadly.
how are you going to tie all this together?
We absolutely have considered the complexity of the idea and that is what makes it fun!! There is absolutely no practical use for doing this. It is for the fun of it. If it bothers you think of it as the Rube Goldberg machine of boost generation.
A wast Gate is the answer to keeping boost constant. Just spin the compressor at max RPM and set your boost limit. Bleed excess boost back to the intake or better yet add in a air tank and store it that would then be released upon the triggering of the motor to overcome the lag as the motor spins up. Yes I know even more complicated. OR you could put a dc motor controller that is controlled by a signal from a map sensor that would in turn regulate the RPMs of the starter motor to maintain constant boost. This is even more complicated and should be looked in to.
You want a simple and cheap momentary instant boost of power?
Use. NOX ! push the button and air and extra fuel is squirted in making more power.
light simple easy
And what fun is that to build. I like the journey as much or more than the destination when it comes to things like this. The journey is figuring it out, problem solving, testing things, braking things, rebuilding, testing, and in the end it is a 50/50 likelihood that you will just end up with a pile of useless parts. I am ok with that. That is fun and how you learn things.
shagles said:In case it hasn't been said already (I could have missed it), using a starter for anything more than a couple seconds at a time will most likely make it fail drastically quicker than normal.
I think this is way overblown. I have cranked starters for many seconds with out issue. However if you want to make them last you need to add cooling and MOST importantly make sure it is grounded well. A friend of mine rebuilds starters and alternators and he blames cooling and grounding as the primary issues with starters failing. As he put it you are standing still while starting and there is no airflow. They over heat really fast when cranked to long. As for grounding I can see that as well as we all know grounding is always an issue especially in older cars.
I have a clutched Merc supper charger. The early ones are Eaton M62's. The down side to these is the clutched pulley is very large and because of this you need a proportionately larger crank pulley to make meaningful boost numbers. I found that swapping the snout from an early 90's supper charged 3800 from a Buick solves this issue and gives you a 2 3/8" pulley. You loose the clutch but you get a fantastic little unit. It reminds me of the small twin supper chargers used on some European V8 cars of the 90's and early 2000's. I think it was Aston Martin that did it but not 100% on that. I have one all set up. I can post a pic later here.
In reply to dean1484 :
I'm more thinking if you tried to use it during autocross runs or something similar where you'd essentially be cranking it for 60ish seconds non stop, multiple times. Not sure if they'd hold up to that or not.
In reply to shagles :
Well there is only one way to find out!!!
I think I am going to bolt a starter and a supper charger to a piece of plywood and bench test things first. Lets see what happens. Lets see if the starter can turn the supper charger with say 12-16 lbs of boost against it. I am thinking that it may not be able to make more than a couple lbs of boost simply because of the pressers against the impellers from the boost in the
"manifold". We can also see / test the temps of the starter and measure power draw under load. Should be simple to make up and interesting to see what happens.
I use Toyota gear-reduction starters for midget go karts in my senior metal class. They have a ton of torque, and -can- run for a reasonable length of time:
BUT, wouldn't it be cool to build something like the Boost Caboose?
(SBC on a trailer turning a centrifugal supercharger, which is fed into the engine of the car pulling it)
wlkelley3 said:I remember watching the Mad Max supercharger thing and wondered how that would work. I came up with the idea of using a air conditioning electric clutch on the drive pulley for a supercharger. Not sure how/if it would work on a GMC style blower that feeds direct into the head but may work with the type that mounts off the intake manifold. Don't really know much about superchargers. Would air/fuel flow through the blower that isn't turning? Which is my thoughts on the top mounted GMC style blower.
I think I remember reading that a roots style blower will freewheel if it's not driven. I am not sure it will start easily that way though.
Big time losses in gears to the supercharger. I've seen a starter motor used to raise and lower a convertible top, though (British cars).
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