Comparison between a supercharger and a turbocharger at the same boost level

[buditjoenawan]

Same dyno, same peak boost. Just to compare the different torque curves and the resultant discrepancy due to pulley drag on the supercharger. If pulley drag is not present, then the supercharger and turbocharger puts out the same power, boost for boost.

budi

[DJCarbine]

You can't just compare PSI in forced induction.... efficiency comes into play, 10psi on turbo A might be different than 10psi on turbo B

Your dyno could be two different turbocharger models with different power outputs even though they are running the same amount of boost

[SloS14]

sorry, but horribly misinformed comparison.

[ptuning]

A PROPERLY set-up turbo system will make more power and torque everywhere on the same engine using the same fuel. The choice on what FI system to get usually comes down to cost and a few other factors, so turbos may not be a good fit for everyone. CARB exemption is an important consideration for California residents. This is where a SC may be a better fit, for instance.

Blue - PTUNING GT3076R Turbo 6.2 psi on 93 Octane Pump Gas
Green - Stock BRZ
Red - Centri-SC (raised rev limiter with no other mods)
Pencil - Blower (Early dyno sheet converted KW to WHP and WHP to WTQ) - Will update with new info once more dyno charts are posted.

[buditjoenawan]

Originally Posted by SloS14

sorry, but horribly misinformed comparison.

Please enlighten us?

budi

[DJCarbine]

Originally Posted by buditjoenawan

Please enlighten us?

budi

10psi is not 10psi when they are on different turbochargers. You have to take into account FLOW at that pressure.

[buditjoenawan]

Originally Posted by DJCarbine

10psi is not 10psi when they are on different turbochargers. You have to take into account FLOW at that pressure.

Ah, but I disagree. 10psi IS 10psi: assuming you normalize intake air temps. It doesn't matter how the boost is made and by what, because that measurement is taken in the manifold. On the same motor, 10psi of boost measures the same restriction to airflow made with a turbocharger and a supercharger.

budi

[Opposed]

Originally Posted by buditjoenawan

Ah, but I disagree. 10psi IS 10psi: assuming you normalize intake air temps. It doesn't matter how the boost is made and by what, because that measurement is taken in the manifold. On the same motor, 10psi of boost measures the same restriction to airflow made with a turbocharger and a supercharger.

budi

So 10psi on a T25 turbo is the same as 10psi on an 80mm turbo?

[DJCarbine]

Originally Posted by buditjoenawan

Ah, but I disagree. 10psi IS 10psi: assuming you normalize intake air temps. It doesn't matter how the boost is made and by what, because that measurement is taken in the manifold. On the same motor, 10psi of boost measures the same restriction to airflow made with a turbocharger and a supercharger.

budi

10psi of hot air is the same as 10psi of cold air?
I know you said "assuming you normalize intake temps" but when you normalize everything such as backpressure, compressor/turbine housing size etc..... you end up with 2 of the same turbocharger. Its the differences that make... a difference.

[djdnz]

Originally Posted by buditjoenawan

Same dyno, same peak boost. Just to compare the different torque curves and the resultant discrepancy due to pulley drag on the supercharger. If pulley drag is not present, then the supercharger and turbocharger puts out the same power, boost for boost.

budi

It's not "pulley drag", look at the boost chart. If you still don't understand, go read more before you start any more new threads.

[charged86]

What @DJCarbine is trying to explain is cubic feet per minute cfm. Also efficiency ranges play a factor. And those are complicated graphs.

[jamesm]

10psi != 10psi unless they're coming from the same turbo. do we really have to go over this again?

[Sellout]

Originally Posted by jamesm

10psi != 10psi unless they're coming from the same turbo. do we really have to go over this again?

No. Let people who have never driven a vehicle on two different turbos continue spouting crap. Everyone else knows better.

[Scoobyrs25]

Originally Posted by Sellout

No. Let people who have never driven a vehicle on two different turbos continue spouting crap. Everyone else knows better.

he he... word. Volume and pressure are two different things entirely. Also, just to add to the fun: I have personally tuned an HKS supercharged FRS and my turbocharged BRZ. At 10 lbs of boost with the supercharger and only 8 lbs of boost with my GT2871, my turbo BRZ made 30 more hp and way more torque, much sooner. I don't remember the tq numbers, but for example, Evasive's car makes 200 tq at 4000 rpm, and my turbo does that at 2000 rpm. I'm sorry, but superchargers on these cars just seem to be lacking.