Getting low end from a centri ?

[Jackson1320]

i don’t see how one can firmly say a centrifugal at 10psi will be slower than a centrifugal wastegated down to 10psi just cuz Boost comes sooner when we can’t even firmly say that a TVS at 10psi is faster than a 10psi centri and the TVS’ boost is instant

I’m not saying that one makes more power than the other at 10 psi. I’m saying that one will get to 10 psi 3000 or 4000 RPM sooner

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[Jackson1320]

Yea and


Yea and compressor maps don't change because of a wastegate.... Now if you change the gearing hmmmmm?

Seriously? A torque booster setup is not just a waistgate. You pulley down effectively changing the gear ratio. So if you are setup to run 20psi at redline. you will get to 10psi a lot sooner than if you are setup for 10psi at redline. This is what a torque booster setup is for. It will allow you to get to 10psi when you would have only been at around 6 normally. It is designed to make boost sooner. If you can make 10psi at 4000rpm and your opponent makes 6psi at 4000rpm. You don’t think you have a advantage?

 

[engineermike]

The problem with the wastegate setup is your parasitic losses are higher after the wastegate opens. Boost pressure might be the same but the gated one is moving more air (that is relieved to atmosphere) but you are still paying the hp price for compressing all of that air to the set point.

 

[WildHorse]

Is it in any way possible to tune a centri to make it feel like a tvs

Negative. Centri is just a belt driven turbo.

 

[Jackson1320]

The problem with the wastegate setup is your parasitic losses are higher after the wastegate opens. Boost pressure might be the same but the gated one is moving more air (that is relieved to atmosphere) but you are still paying the hp price for compressing all of that air to the set point.

i’m sorry but this time you make no sense. You are only paying to compress it to the 10 pound. you don’t have to pay for the 20 pound because there’s not 20 pounds of back pressure in the system. They both have the same overall pressure in the system and both are paying Close to the same price in parasitic loss.
Turning the supercharger doesn’t take much power until it starts making pressure. Then it gets harder to turn. The more pressure the harder to turn. They are both making the same pressure so it doesn’t really make much difference. is there more parasitic loss? maybe a very little, but the boost more than makes up for it

 

[Jackson1320]

The problem with the wastegate setup is your parasitic losses are higher after the wastegate opens. Boost pressure might be the same but the gated one is moving more air (that is relieved to atmosphere) but you are still paying the hp price for compressing all of that air to the set point.

https://www.beefcakeracing.com/torque-booster-2011mustang/

 

[SolarFlare]

I’m not saying that one makes more power than the other at 10 psi. I’m saying that one will get to 10 psi 3000 or 4000 RPM sooner

Based on that theory a TVS or Whipple car would be a no questions asked faster than a centrifugal setup both at 10psi.....since both reach 10psi before a centrifugal....but that’s isn’t the case.

if 2-4k rpm power is your thing for onramps and passing power in 5 or 6 gear, OP, just get a TVS. Nothing wrong with it.

 

[Jackson1320]

Based on that theory a TVS or Whipple car would be a no questions asked faster than a centrifugal setup both at 10psi.....since both reach 10psi before a centrifugal....but that’s isn’t the case.

if 2-4k rpm power is your thing for onramps and passing power in 5 or 6 gear, OP, just get a TVS. Nothing wrong with it.

that is the case. A TVS and Whipple make boost a lot sooner than a centrifugal. So they both make more power earlier in the rpms. That’s not theory it’s fact. But they are not as efficient in the higher rpms where a centrifugal really shines. So a TVS has the advantage off the line (if it hooks) over a centrifugal. So the centrifugal
Will play catch-up at first yes. but it will quickly even the odds

 

[SolarFlare]

I’m with @80FoxCoupe , pick the blower AND pulley that best suits your power goals when it comes to centrifugals.....if you enjoy part throttle stuff go PD.......leave turbo complexities to turbo cars.

 

[Jackson1320]

I’m with @80FoxCoupe , pick the blower AND pulley that best suits your power goals when it comes to centrifugals.....if you enjoy part throttle stuff go PD.......leave turbo complexities to turbo cars.

I’ll agree that’s probably the best option for 90% of centrifugal cars. I was just answering op question. And the only way I know of to get anything close to a tvs down low in the rpms with a centrifugal is to use a torque booster setup

 

[80FoxCoupe]

I’ll agree that’s probably the best option for 90% of centrifugal cars. I was just answering op question. And the only way I know of to get anything close to a tvs down low in the rpms with a centrifugal is to use a torque booster setup

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

 

[80FoxCoupe]

Hey guys so I may take advantage of the black Friday sales and buy a blower. I love the vmp . I like alot how its seems to have the best low end hit . However the centris seem to be alot more cost friendly . Is it in any way possible to tune a centri to make it feel like a tvs ? I'm just worried I'll regret it after if I get a centri over a tvs . need some help . how different do these blowers feel and where

Just buy the TVS or a diesel truck for that "low end" you desire!

 

[engineermike]

i’m sorry but this time you make no sense. You are only paying to compress it to the 10 pound. you don’t have to pay for the 20 pound because there’s not 20 pounds of back pressure in the system. They both have the same overall pressure in the system and both are paying Close to the same price in parasitic loss.
Turning the supercharger doesn’t take much power until it starts making pressure. Then it gets harder to turn. The more pressure the harder to turn. They are both making the same pressure so it doesn’t really make much difference. is there more parasitic loss? maybe a very little, but the boost more than makes up for it

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.

 

[engineermike]

This does give me an idea though...why not pulley the centrif faster then use the torque demand tables in the tune to reduce torque demand at high rpm. This would reduce throttle opening and boost up top but give you everything it has in the midrange and would be simpler than a “wastegate”. Ford already does something similar on many consumer vehicles.

 

[80FoxCoupe]

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

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