Getting low end from a centri ?

[Jackson1320]

just buy a Vortech JT-B with a 3.33 Pulley and a 20% lower, and be done. There, instant torque and high end.

And a blown engine

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[Jackson1320]

Forgive my ignorance here, but surely the impeller speed required to deliver 12psi of boost at 3k would be WELL outside the operating limit of most centris at 8k? Or not?

Who said 12 psi at 3000 RPM. Who said 12 psi at 3000 RPM I thought it Was 4000 to 3000 RPMs sooner And was just used as an example

 

[Jackson1320]

While the concept does make sense, it does not necessarily translate into increased performance at the strip.

I agree. 5000hp doesn’t mean that you will get down the track any faster than 500hp. There’s more to it than just raw horsepower. but it does mean that you have the capabilities of a faster time if everything worked out perfect in both situation. If a car can develop max boost sooner and Hold that same boost all the way. it has the potential of a faster time Then a car that develops Max boost at red line. how much? who knows. but it will definitely make more mid range horsepower

 

[Jackson1320]

Oh good another thermodynamics problem. The power to drive a centrifugal compressor, often referred to as parasitic loss, is directly proportional to the mass flow through the compressor. This isn’t even arguable. This math is used every single day all across industry. So if two centrifugal compressors both discharge at 10 psi but one flows 30% more air (air that is vented to atmosphere), then the one flowing 30% more air will take 30% more power to turn it. If the compressor is near stonewall then it can be much worse.

If your theory holds water tell me why a torque booster makes more midrange power and even more topend power than a regular pulley setup. At the same or slightly less boost

 

[Dominant1]

Yeah do an ls swap put a d1x on it & it will smoke those tvs’s outta the hole midrange and top end..

 

[Jackson1320]

I’m not saying that the torque booster setup does not have its downsides or that the extra power is free. I’m just saying that the pros heavily outweigh the cons

 

[Jackson1320]

Yeah do an ls swap put a d1x on it & it will smoke those tvs’s outta the hole midrange and top end..

OK whoa now let’s not get to far off bring it back to earth. you’re comparing apples to grapes.

 

[Jackson1320]

Good points @engineermike , def could be an explanation why gated cars dont really perform any better.

Torque boosted cars do you perform better just not in the way that you are expecting. they perform better in the fact that they make more power that doesn’t mean better track time. just bigger numbers

 

[Dominant1]

OK whoa now let’s not get to far off bring it back to earth. you’re comparing apples to grapes.

Ok then Do a 7.3 swap put a D1x on it and it will smoke those tvs’s outta the hole, midrange, and top end..you want more torque you’ll want a bigger engine. For me its not all about low end torque.

 

[Jackson1320]

Ok then Do a 7.3 swap put a D1x on it and it will smoke those tvs’s outta the hole, midrange, and top end..you want more torque you’ll want a bigger engine. For me its not all about low end torque.

More displacement equals more torque. Correct, that’s why a PD blower makes so much more torque. because it’s just like having a bigger engine

 

[engineermike]

The parasitic loss is not directly proportional to the mass air it is directly proportional to compression . If you ever run your pro charger without any piping you’ll feel the air coming out of it is not hot. it does not get hotter until it gets compressed. Just moving air does not make it hotter. A fan does not heat up air. it’s compression that adds heat and parasitic loss

Holy cow....the parasitic loss is definitely and absolutely proportional to the mass flow through the compressor. Every book on compressors ever written will tell you this. It’s not even arguable. It is related to compression as well, but not directly proportional, as it is to mass flow.

As for the heat, I’m not sure if you confused me with someone else because I hadn’t mentioned it. But the way it works with a centrif is you are without a doubt moving where the you are on the compressor map. If you move to a lower efficiency island then it will cause the charge temp to increase and cause even more parasitic loss, compounding the issue. If I had the compressor map, I could calculate it exactly for you.

By the way, the air exiting the “wastegate” will be 200-250 deg F. The heat and mass flow of this wasted air represents the wasted energy and increase in parasitic loss associated with the “wastegate”.

 

[engineermike]

If your theory holds water tell me why a torque booster makes more midrange power and even more topend power than a regular pulley setup. At the same or slightly less boost

As suspect as that graph is (since when is 2 psi worth 80 ftlb?), it actually does demonstrate my point, that when the boost is unison the non-wastegated trace makes about 20 more hp.

 

[Jackson1320]

Holy cow....the parasitic loss is definitely and absolutely proportional to the mass flow through the compressor. Every book on compressors ever written will tell you this. It’s not even arguable. It is related to compression as well, but not directly proportional, as it is to mass flow.

As for the heat, I’m not sure if you confused me with someone else because I hadn’t mentioned it. But the way it works with a centrif is you are without a doubt moving where the you are on the compressor map. If you move to a lower efficiency island then it will cause the charge temp to increase and cause even more parasitic loss, compounding the issue. If I had the compressor map, I could calculate it exactly for you.

By the way, the air exiting the “wastegate” will be 200-250 deg F. The heat and mass flow of this wasted air represents the wasted energy and increase in parasitic loss associated with the “wastegate”.

The parasitic loss is almost nothing on a open centrifugal just inhaling and exhaling. no piping just venting to atmosphere. Because it is not compressing the air. It also does not increase in temperature. Also because it is not compressing the air.
But just for arguments sake let’s say you’re right since a pro chargers parasitic lost at 10 pounds of boost is 7-8% let’s add 30% and now we are at a whopping 2% more loss But a gain of 10% more power. What is the problem?

 

[SolarFlare]

Any increase shown on dyno are due to dyno margin of error or tune changes. Or much better weather. Both cars making 10psi peak one ain’t making 20-30whp more lol

 

[Jackson1320]

Any increase shown on dyno are due to dyno margin of error or tune changes. Or much better weather. Both cars making 10psi peak one ain’t making 20-30whp more lol

Maybe, Maybe not. It will make more power if it has more boost. Also there are no tuning changes that the torque booster would benefit from. 99% of the time there are no Tune changes needed

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