Supercharging: the forgotten form of FI

[Type[R]+]

Originally Posted by 82mm 4g63

The only beef I have with that Bullet SC you linked is "OEM high quality Installation with virtually silent Supercharger operation." Where's the fun in that?

Yes, that does suck.
Can still have 'fully sick' blow off valve!

[madfast]

Originally Posted by 82mm 4g63

The only beef I have with that Bullet SC you linked is "OEM high quality Installation with virtually silent Supercharger operation." Where's the fun in that?



Water to Air IC's are superior for race cars, not for daily drivers. Water to air coolers are more efficient so they can be smaller. You can drop ice in the reservoir to radically reduce charge air temps on the track. And you can mount them almost anywhere without worrying about them getting maximum airflow.

However, in a daily driver they can get overwhelmed and heat soaked causing them to be extremely inefficient in long duration trips. That combined with all the added accessories and parts that can fail, I would never go with a water to air intercooler unless it was exclusively a track car. Air to air can handle the job just fine.

this info sound more relevant to turbos than superchargers. first, roots blowers are air pumps. there is no internal compression. thats why old school blowers dont even use intercoolers. instead they used water spray, etc.

secondly, the boost is directly proportional to rpm on a roots. so at higher boost levels, you should be traveling faster. faster means more air over the heat exchanger of the water/air intercooler.

thridly, the roots blowers have bypass valves. the engine may not even see boost at low load. the water pump is independent and can still circulate.

so imo on a roots blower, water to air is perfect. compact and efficient. heat soak is overrated on a roots...

[Neutral_Eyes]

Originally Posted by Type[R]+

close, but still no Veyron.

I thought matching the top speed and standing mile while besting it at the quarter mile would suffice for an '86 Trans Am... Are you talking Super Sport? Should we drift them both?

[u2b]j7oKfwSV3hQ[/u2b]

[Random_Art]

Originally Posted by 82mm 4g63

Almost as funny as this.

[u2b]http://www.youtube.com/watch?v=mOmm5cw0DqE[/u2b]

Wood grain side panels and all. lol

even though the embed doesn't seem to be working for me for some reason... That's one of my favorite youtube clips.

[Matador]

Originally Posted by serialk11r

So with the pump disengaged, the engine has to pull air through the pump...I have a feeling that doesn't really work with a positive displacement pump. Thus, a bypass valve so the engine doesn't pull air through the pump.

Ahhh. Gotcha


As din Said, it does have one.

[82mm 4g63]

Originally Posted by madfast

this info sound more relevant to turbos than superchargers. first, roots blowers are air pumps. there is no internal compression. thats why old school blowers dont even use intercoolers. instead they used water spray, etc.

secondly, the boost is directly proportional to rpm on a roots. so at higher boost levels, you should be traveling faster. faster means more air over the heat exchanger of the water/air intercooler.

thridly, the roots blowers have bypass valves. the engine may not even see boost at low load. the water pump is independent and can still circulate.

so imo on a roots blower, water to air is perfect. compact and efficient. heat soak is overrated on a roots...

It's may apply more to turbocharging, but it does also apply to supercharging. Airflow is crucial, obviously, and when in motion you don't have too much of a problem. With w/ater intercooling the problem is when you're in stop and go/around town traffic. When you're sitting there stopped at a red light you're bound to head soak the water. It takes a lot more time to cool down a gallon or two of water than just the a/a heat exchanger.

If you're anything like me and you beat on it on your way to get some fast food and let it sit while you're eating, expect that water to be nice and toasty when you start her up again.

If I really wanted to reduce intake temperatures I would just spray my A/A.

[madfast]

Originally Posted by 82mm 4g63

It's may apply more to turbocharging, but it does also apply to supercharging. Airflow is crucial, obviously, and when in motion you don't have too much of a problem. With w/ater intercooling the problem is when you're in stop and go/around town traffic. When you're sitting there stopped at a red light you're bound to head soak the water. It takes a lot more time to cool down a gallon or two of water than just the a/a heat exchanger.

If you're anything like me and you beat on it on your way to get some fast food and let it sit while you're eating, expect that water to be nice and toasty when you start her up again.

If I really wanted to reduce intake temperatures I would just spray my A/A.

i totally get what you're saying, but imo its more of a theoretical problem vs an empirical one. if you're sitting in traffic, then you're not boosting. the water pump can still run and can still circulate the water. granted heat exchange isnt very effective when you're not moving, but still, its better than just sitting there.

traffic jam over, road opens up. you let loose. the heat exchanger now is getting adequate air. efficiency goes way up. the only thing to worry about is how much heat the water soaked, and how fast you can get rid of it. with the independent pump circulating while you were standing still, just how much heat was soaked? i dunno if anybody has ever done an instrumented test, but from what i've read i dont hear too many people complaining about heat soak.

and above all else, its not the end of the world. it only happens in certain conditions and it goes away. but something like turbo lag, now that is a problem that never goes away...

[Dimman]

Originally Posted by madfast

i totally get what you're saying, but imo its more of a theoretical problem vs an empirical one. if you're sitting in traffic, then you're not boosting. the water pump can still run and can still circulate the water. granted heat exchange isnt very effective when you're not moving, but still, its better than just sitting there.

traffic jam over, road opens up. you let loose. the heat exchanger now is getting adequate air. efficiency goes way up. the only thing to worry about is how much heat the water soaked, and how fast you can get rid of it. with the independent pump circulating while you were standing still, just how much heat was soaked? i dunno if anybody has ever done an instrumented test, but from what i've read i dont hear people complaining about heat soak.

and above all else, its not the end of the world. it only happens in certain conditions and it goes away. but something like turbo lag, now that is a problem that never goes away...

This is not really any different than the potential problem of undersizing a radiator. Sized right, I don't think a water-air will have any heat-soak problems.

[madfast]

Originally Posted by Dimman

This is not really any different than the potential problem of undersizing a radiator. Sized right, I don't think a water-air will have any heat-soak problems.

yeah i think a lot of it has to do with the fact that companies dont want to use a lot of fluid in order to to decrease overall weight. its a balancing act for sure.

it doesnt really matter anyways because if you go with a roots SC then you're almost stuck with water to air. if you rotrex or turbo, its basically standard to go air to air. you likely have no choice in the matter!

[Dimman]

Originally Posted by madfast

yeah i think a lot of it has to do with the fact that companies dont want to use a lot of fluid in order to to decrease overall weight. its a balancing act for sure.

it doesnt really matter anyways because if you go with a roots SC then you're almost stuck with water to air. if you rotrex or turbo, its basically standard to go air to air. you likely have no choice in the matter!

The MR2 we mentioned had a small air-air with its Roots-type blower. I guess it's about ease of packaging.

[serialk11r]

Originally Posted by madfast

but these guys are number chasers. they have to sell their kits and people, stupid people, look only at numbers. when you get to "ludicrous speed" level, its a HP war and a supercharger can never compete.

Well the thing is, from an engineering standpoint a turbo is better in almost every single way. You get more for less. A supercharger can't compete for the very good reasons I described.

Now something I'd like to see is electric spool assist on a turbo...something like a starter motor producing like 4kW just to spin it up. We can get more complicated and do sequential twin (twin-scroll ideally) turbo with dual stage compression (with bypass valve for low rpm), and a valve to control exhaust gas flow to the second turbine, simpler than variable vane, very little lag

[madfast]

Originally Posted by serialk11r

Well the thing is, from an engineering standpoint a turbo is better in almost every single way. You get more for less. A supercharger can't compete for the very good reasons I described.

OBVIOUSLY WRONG blanket statement

its 1000% application specific. if i want response and no lag, no turbo will be better than a sc for that application.

Originally Posted by serialk11r

Now something I'd like to see is electric spool assist on a turbo...something like a starter motor producing like 4kW just to spin it up. We can get more complicated and do sequential twin (twin-scroll ideally) turbo with dual stage compression (with bypass valve for low rpm), and a valve to control exhaust gas flow to the second turbine, simpler than variable vane, very little lag

vaporware! this idea has been kicked around for decades. and we've yet to see anything. the closest thing i can think of is rotrex's electric sc. i believe its only a concept at this point, but its close.

[[es vi: eks]]

I always liked the Latham Supercharger...
Supost to be very effiecent, Low heat but very expensive to make.

Axial brought the rights to building these

http://www.axialflow.com/history.htm

http://www.axialflow.com/products.htm

[Type[R]+]

Originally Posted by [es vi: eks]

I always liked the Latham Supercharger...
Supost to be very effiecent, Low heat but very expensive to make.

Axial brought the rights to building these

http://www.axialflow.com/history.htm

http://www.axialflow.com/products.htm

looks like any gas turbine (I work in power generation!). I don't know about low heat, compression = heat. Also don't know about efficiencies either, we have got variable blading, as well as bleed valves to prevent compressor stall at low RPM.

Good outside of the box thinking, but that design has essentially been around for centuries. It would be great to see this working in real life!