Speed Force Racing S2 SC Kits!!
03-21-2002, 02:22 AM
#16
Burning Brakes
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CBass,
we offer that conversion to lower compression...its quite a bit of work...and yes, its our living, so when we charge what we do, we make sure its fair, we don't hype, we deliver. Anyone that calls us, gets the straight talk, pro's and con's, we let them make up their mind without the sales bull**** and pressure...so, like they say,...how fast do you want to go$$$$$
Its the oldest saying since hot rodding has been around...
we offer that conversion to lower compression...its quite a bit of work...and yes, its our living, so when we charge what we do, we make sure its fair, we don't hype, we deliver. Anyone that calls us, gets the straight talk, pro's and con's, we let them make up their mind without the sales bull**** and pressure...so, like they say,...how fast do you want to go$$$$$
Its the oldest saying since hot rodding has been around...
03-21-2002, 04:54 PM
#17
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[quote]Originally posted by CBass:
Don't get me wrong, I don't mean to knock your engineering work, but people pay $7000 for that?<hr></blockquote>It's that "Porsche thing." You charge what you think the customer base will pay. You can buy a Whipple supercharger kit for the <a href="http://www.whipplesuperchargers.com/ptcruiser.html" target="_blank">PT Cruiser</a> for $3650 and it includes a lot more pieces and a lot more engineering, but it's a mass market device too, not built one at a time.
[quote]A turbo car with 250 bhp will in all likelyhood be quite a bit quicker than a supercharged car with 250 bhp.<hr></blockquote>Only if you are comparing turbo to centrifugal supercharger. A positive displacement supercharger (Eaton or Whipple) can make full boost at a lower rpm than the turbo, but it's not going to make as much peak HP nearly as easily because of the lower efficiency.
Don't get me wrong, I don't mean to knock your engineering work, but people pay $7000 for that?<hr></blockquote>It's that "Porsche thing." You charge what you think the customer base will pay. You can buy a Whipple supercharger kit for the <a href="http://www.whipplesuperchargers.com/ptcruiser.html" target="_blank">PT Cruiser</a> for $3650 and it includes a lot more pieces and a lot more engineering, but it's a mass market device too, not built one at a time.
[quote]A turbo car with 250 bhp will in all likelyhood be quite a bit quicker than a supercharged car with 250 bhp.<hr></blockquote>Only if you are comparing turbo to centrifugal supercharger. A positive displacement supercharger (Eaton or Whipple) can make full boost at a lower rpm than the turbo, but it's not going to make as much peak HP nearly as easily because of the lower efficiency.
04-03-2002, 02:39 PM
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[quote]Originally posted by CBass:
<strong>Explain how the Eaton blower makes better low end boost than a turbo. I don't know much about positive displacement superchargers.</strong><hr></blockquote>First, centrifugal superchargers are similar to a turbo except the compressor is mechanically driven instead of exhaust driven. The compressor needs to run at very high rpms in order to make boost... and the faster you run them the more boost (flow) they produce.
The positive displacement supercharger on the other hand, such as the <a href="http://www.automotive.eaton.com/product/engine_controls/superchargers.html" target="_blank">Eaton</a>, is a modified roots design that uses counter-rotating lobes to pump air into the engine and compress it in the intake tract. Each rotation of the supercharger produces a set volume output which is relatively constant with rpm. If it makes 5 psi at 4000 engine rpm it also makes 5 psi at 2000 rpm (Ideally. In the real world it will make less boost in the upper rpms due to efficiency changes).
So, with proper design you can essentially get full boost just off idle, but will see some tapering off at high rpm. The positive displacement superchargers are very good at making nice flat torque curves, but are not as good at making peak HP comapred to the turbo or centrifugal supercharger, and they generate more heat of compression because of the lower efficiencey design.
The <a href="http://www.whipplesuperchargers.com" target="_blank">Whipple</a> supercharger is similar to the Eaton in that it is a positive displacement unit, but it's different in that it's a twin screw design that actually compresses air in the supercharger as opposed to in the manifold like the Eaton. This is a more efficient design, but is also more costly.
<strong>Explain how the Eaton blower makes better low end boost than a turbo. I don't know much about positive displacement superchargers.</strong><hr></blockquote>First, centrifugal superchargers are similar to a turbo except the compressor is mechanically driven instead of exhaust driven. The compressor needs to run at very high rpms in order to make boost... and the faster you run them the more boost (flow) they produce.
The positive displacement supercharger on the other hand, such as the <a href="http://www.automotive.eaton.com/product/engine_controls/superchargers.html" target="_blank">Eaton</a>, is a modified roots design that uses counter-rotating lobes to pump air into the engine and compress it in the intake tract. Each rotation of the supercharger produces a set volume output which is relatively constant with rpm. If it makes 5 psi at 4000 engine rpm it also makes 5 psi at 2000 rpm (Ideally. In the real world it will make less boost in the upper rpms due to efficiency changes).
So, with proper design you can essentially get full boost just off idle, but will see some tapering off at high rpm. The positive displacement superchargers are very good at making nice flat torque curves, but are not as good at making peak HP comapred to the turbo or centrifugal supercharger, and they generate more heat of compression because of the lower efficiencey design.
The <a href="http://www.whipplesuperchargers.com" target="_blank">Whipple</a> supercharger is similar to the Eaton in that it is a positive displacement unit, but it's different in that it's a twin screw design that actually compresses air in the supercharger as opposed to in the manifold like the Eaton. This is a more efficient design, but is also more costly.
