drive pressure

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wanna be
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Aug 5, 2008
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Can someone educate me on drive pressure. How is it checked? What kind of pressure does a person want to stay under? How much pressure will a S475 handle?
 
drive pressure and boost pressure should be as close as possible to a 1:1 ratio...you measure drive pressure in the manifold with a boost gauge
 
Just make sure you run the line to your boost gauge through as much copper as possible to dissipate exhaust heat.

I usually wrap a 6-8 feet around a brake-cleaner can, then you have a nice neat coil and your gauge will not get damaged from heat.
 
But it will probably get stopped up with soot. Is there a filter people prefer to use to go in the line to the gauge?
 
yoshi470 said:
drive pressure and boost pressure should be as close as possible to a 1:1 ratio...you measure drive pressure in the manifold with a boost gauge
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yes i would like to know the same thing. how much pressure is to much. is it totally relevant to how much boost there is or what is the max you should see in a system period.
 
Pretty much keep it close to 1:1 if you can, with the tighter housings and smaller turbine wheels you typically will have trouble doing that.
 
High drive pressure raises exhaust temperature, and is hard on the turbo bearings but in all reality, most setups will make more power by tightening the wastegate and letting drive pressure go as high as it can.

When you start playing with twin turbos is when drive pressure and wastegating can help make more power. For example, bypassing a tight top turbo's turbine wheel and letting exhaust work on the larger turbo's massive turbine wheel will often increase peak HP. On a single turbo application, max power will usually be made just as the compressor wheel flys apart or the bearings give up. Wastegates are usually set to limit turbo speed and the 1:1 ratio is a good number where you get probably 80-85% of a turbo's airflow potential without severely beating the bearings or superheating the exhaust tract.


This is all my opinion, others will have different views on wastegating.
 
Big Blue24 said:
High drive pressure raises exhaust temperature, and is hard on the turbo bearings but in all reality, most setups will make more power by tightening the wastegate and letting drive pressure go as high as it can.

When you start playing with twin turbos is when drive pressure and wastegating can help make more power. For example, bypassing a tight top turbo's turbine wheel and letting exhaust work on the larger turbo's massive turbine wheel will often increase peak HP. On a single turbo application, max power will usually be made just as the compressor wheel flys apart or the bearings give up. Wastegates are usually set to limit turbo speed and the 1:1 ratio is a good number where you get probably 80-85% of a turbo's airflow potential without severely beating the bearings or superheating the exhaust tract.


This is all my opinion, others will have different views on wastegating.
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I want to know how it effects the head gasket and valve train. does anyone have any info, also sorry if I hijcaked the thread, this will be last post on this one.
 
Big Blue24 said:
High drive pressure raises exhaust temperature, and is hard on the turbo bearings but in all reality, most setups will make more power by tightening the wastegate and letting drive pressure go as high as it can.

When you start playing with twin turbos is when drive pressure and wastegating can help make more power. For example, bypassing a tight top turbo's turbine wheel and letting exhaust work on the larger turbo's massive turbine wheel will often increase peak HP. On a single turbo application, max power will usually be made just as the compressor wheel flys apart or the bearings give up. Wastegates are usually set to limit turbo speed and the 1:1 ratio is a good number where you get probably 80-85% of a turbo's airflow potential without severely beating the bearings or superheating the exhaust tract.


This is all my opinion, others will have different views on wastegating.
Click to expand...
Glad to hear that somebody else has the same opinion as me when it comes to a single turbo setup. I've played with three different turbos on the Dyno(USB, Pro Street 66, and a Super B Special) I made runs on all three with the boost set from 40-60 psi. All three turbos made the most power in the 55-60 psi range. At this high of boost numbers the turbos should be out of the map and drive pressures should be through the roof. On paper it should lose power, but yet it makes more.
 
... that's because a compressor's max power P/R usually isn't the same as it's most efficient P/R.
 
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