Centri Boys, Need Your Wisdom!

[SolarFlare]

If you want PD driving habits buy a PD!!

a wastegate makes an efficient centrifugal act like an inefficient centrifugal with belt slip

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[bluebeastsrt]

I read this entire thread. Thanks for all that participated. The level of knowledge runs the gambit of good to mind blowingly wrong. Gotta love the internet.

 

[andrewtac]

a wastegate makes an efficient centrifugal act like an inefficient centrifugal with belt slip

I was going to do this, but I kept coming to this conclusion. Extra heat, more power pulled from the motor, and so on. Tuner also recommend not to do it, makes sense.

 

[andrewtac]

I was thinking more with a wastegate I would be able to achieve max boost sooner. Also it seems like I'd have the ability to run different tunes with different boost levels.

You can pulley to different boost levels, no need to change the tune.

 

[engineermike]

Extra heat, more power pulled from the motor, and so on...

How did you arrive at these two conclusions? They are largely incorrect, debatable at best, but I would be happy to provide logs or calculations to prove it.

 

[andrewtac]

How did you arrive at these two conclusions? They are largely incorrect, debatable at best, but I would be happy to provide logs or calculations to prove it.

Please provide logs then when you waste gated a centri and got those results. This was purely a guess on my part, assuming spinning a centri to a higher rpm would require more crank HP (not sure how you'd prove or disprove this with logs) and also generate more heat with more compression of the air at a higher rpm. Calculations welcome as well.

 

[engineermike]

@andrewtac I think we’re talking about two different aspects of solarflares post.

A wastegated centrif will pull more power to turn the blower and generate higher charge temp. I go back to this…why try to [inefficiently] make a centrif act like a PD when efficient PD’s are available?

 

[andrewtac]

@andrewtac I think we’re talking about two different aspects of solarflares post.

A wastegated centrif will pull more power to turn the blower and generate higher charge temp. I go back to this…why try to [inefficiently] make a centrif act like a PD when efficient PD’s are available?

Sure but in context of the thread and the post I think you misread my post. Why would a tuner tell me not to get a PD if I wanted it to drive like a PD?

I think we agree, and while I am not a practicing engineer I do remember thermo enough that what I was saying makes sense.

I am like the way the centri drives, was one of the driving factors for me to get it; not going to waste gate it.

 

[SolarFlare]

EDIT: alright I see now that andrew’s tuner did in fact suggest he not get a PD due to higher charge temps and higher drive power necessities.

I respectfully disagree with him. A big PD with a big pulley should be fairly efficient and shouldn’t require big drive power. Given both choices of a wastegated centri or a big PD I’d pick the Pd any day. That’s saying I had a big desire for low end power.

To be clear on something: during normal driving no car should exceed its cooling capacity if designed right. When I say heat soak, I mean as heat build up after hard back to back driving. Make a 1/4 mile pull, come around and make another pull. See if anything was lost from 1st to 2nd or even 3rd pass. That’s heat soak to me.

 

[andrewtac]

Fixed the quote

 

[SolarFlare]

Fixed the quote

Oh ok. You were gonna wastegate your setup and tuner suggested you don’t. Good. Makes sense.

 

[w3ab1ak91]

With having an MT82 does one shine vs the other? I read on another thread that the Whipple will pull better 60' times. But it was comparing 2 autos, one centri and one whipple. Its also been said that having a manual PD is the way to go. Care to shed some scientific jargon on that?

 

[ToughSpecs]

DGR in York, PA can, they've done quite a few already including my buddies 2021 GT with a new VMP Odin setup.

How is DGR for tuning Paxtons? I’m near by and was wondering.

 

[bluebeastsrt]

How is DGR for tuning Paxtons? I’m near by and was wondering.

Depending on where you’re at in PA. You might want to look up Wicked Motorsports in south Jersey. He did a lot of work on my Paxton 15GT. Very good shop for the late model stuff.

 

[LSchicago]

With having an MT82 does one shine vs the other? I read on another thread that the Whipple will pull better 60' times. But it was comparing 2 autos, one centri and one whipple. Its also been said that having a manual PD is the way to go. Care to shed some scientific jargon on that?

I believe going PD with an MT82 is the right way to go, because first gear is much longer (all gears are) than a 10R80.

Driving easy in first, the 10R80 will hit boost around 18 mph. Do the same on an MT82 and it will be probably 30 mph. The MT82 with can effectively use all the extra lower and midrange power of the PD. Your RPM drop is much greater between gears. Each gear starts pulling from a lower RPM than what the auto does. The 10R80 only loses 1200 rpm on the 3rd-4th, 4th-5th, & 6th-7th shifts. Low end torque doesn't help a 10R80 on the street at all. The MT82 will see a benefit of extra low end with it's far spaced gearing.

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