Spool time question

[Veteran]

For those that have had or driven both a Centri and a turbo set up,, which spools quicker ?

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[Jackson1320]

What do you mean? If you are driving and you hammer down you almost instantly have boost with a centrifugal. From a stop (depending on a few things)they both start making boost about the same time. The difference is the centrifugal builds boost with rpm and the turbo goes straight to max boost

 

[Veteran]

What do you mean? If you are driving and you hammer down you almost instantly have boost with a centrifugal. From a stop (depending on a few things)they both start making boost about the same time. The difference is the centrifugal builds boost with rpm and the turbo goes straight to max boost

I guess my question was a bit vague. Let me try again.
A turbo is normally quite flat and from say 3000 is comes on strong . Very strong. Below the 2500/3000 rpm most turbo cars are anemic.
Question is, does a centrifugal spool quicker, and in turn provide a stronger pull up to the 2500/3000 rpm as compared to a Turbo ?
I understand there are variables, but let’s say a gen3 on 93 , one centri one turbo, which would provide more up to the 2500/3000 rpm point.

 

[Louk]

I guess my question was a bit vague. Let me try again.
A turbo is normally quite flat and from say 3000 is comes on strong . Very strong. Below the 2500/3000 rpm most turbo cars are anemic.
Question is, does a centrifugal spool quicker, and in turn provide a stronger pull up to the 2500/3000 rpm as compared to a Turbo ?
I understand there are variables, but let’s say a gen3 on 93 , one centri one turbo, which would provide more up to the 2500/3000 rpm point.

It is my understanding that a CENTRi runs off the crank and boost is a direct correlation of your RPM. Lower RPM lower boost.

A turbo car can create full boost at any RPM(within reason) it will just have lag lower in the RPM range.

 

[XS]

I guess my question was a bit vague. Let me try again.
A turbo is normally quite flat and from say 3000 is comes on strong . Very strong. Below the 2500/3000 rpm most turbo cars are anemic.
Question is, does a centrifugal spool quicker, and in turn provide a stronger pull up to the 2500/3000 rpm as compared to a Turbo ?
I understand there are variables, but let’s say a gen3 on 93 , one centri one turbo, which would provide more up to the 2500/3000 rpm point.

From my experience with a centri Fox Body and from reading many, many, posts here - a centri, unless spun to the moon, will not feel more powerful below 3,000 RPM than a turbo kit. I have seen many posts that say both the Hellion twin 62s and centris come into boost at a noticeable amount around 3,500-4,000 RPM. The difference is the turbos provide more or all the boost at that point, where the centri is still climbing. So a twin kit set for 7lbs will/can give you 7lbs at 4,000 rpm. A centri kit set for 7lbs will give you 3lbs at 4,000 RPM and the full 7lbs at 7,000 RPM - for example. These are hypothetical numbers from base kits I have seen from members posting here. Both kits you can do trick stuff with, like boost by gear on the turbos and wastegates on centris (spinning them faster for lower end boost then bleeding off the unsafe amounts of boost in higher RPMs).

 

[Veteran]

So if I was limited to diving between idle and 3000rpm I’d struggle to feel a difference between centri and turbo ?

 

[XS]

So if I was limited to diving between idle and 3000rpm I’d struggle to feel a difference between centri and turbo ?

That's correct. Again the only FI car I had was an '88 Mustang, but the concept is still the same. I made maybe 2lbs at 3,000 RPM in the Fox. I've seen enough dyno charts here to know that on the coyotes it's essentially the same story with the turbo and centri kits. Maybe a member with differing experience can chime in, but I think you have to spin a centri hard and wastegate it to get an appreciable amount of power below 3,000 RPM. Positive displacement blowers shine in that department.

 

[Bluelightning]

So if I was limited to diving between idle and 3000rpm I’d struggle to feel a difference between centri and turbo ?

For the most part, that is correct. If you want more down low, you need to go twin screw or TVS.

 

[aleccesarenriquez]

Centris don't really "spool". As they gain rpm they make more boost, but it's completely dependent on engine speed. As far as turbos go, the rate they spool at is completely dependent on turbo size. However most turbo and centri power bands will be higher than 4k rpm; under that and they'll feel relatively stock. It's important to note though that turbos generally produce stronger power bands than a centri car, i.e. at the same rpm you'll make more power through a turbo car, even if the peak power might be the same. This is due to the greater torque turbos make, and the fact that it doesn't take horsepower to spin the blower like in a centri setup.

I've had both setups and turbos are by far better in basically every way except cost.

 

[Cory S]

Nothing better than enjoyment of instant boost on the street from a PD/TVS supercharger. I’ve owned them all.

 

[Jackson1320]

So if I was limited to diving between idle and 3000rpm I’d struggle to feel a difference between centri and turbo ?

The centrifugal will be faster to 3000rpm because it is pushing air even at 1500 just not enough to make positive pressure. Even though there’s no positive pressure your engine is still taking in more than it would with turbos. If you size pulleys correctly you can reach full boost on a centrifugal at almost any rpm you want but you have to compromise with max rpm. If you are only going to 4000rpm than a correctly setup centrifugal would be the better option. You could start making boost at 2000rpm. But if you still have to rev to 7500 then overall turbo is better. If you are talking about a road course car N/A is you best option

 

[Jackson1320]

Centris don't really "spool". As they gain rpm they make more boost, but it's completely dependent on engine speed. As far as turbos go, the rate they spool at is completely dependent on turbo size. However most turbo and centri power bands will be higher than 4k rpm; under that and they'll feel relatively stock. It's important to note though that turbos generally produce stronger power bands than a centri car, i.e. at the same rpm you'll make more power through a turbo car, even if the peak power might be the same. This is due to the greater torque turbos make, and the fact that it doesn't take horsepower to spin the blower like in a centri setup.

I've had both setups and turbos are by far better in basically every way except cost.

You can put together a twin turbo kit for half the price of a centrifugal kit if you know what you need

 

[Veteran]

Nothing better than enjoyment of instant boost on the street from a PD/TVS supercharger. I’ve owned them all.

I agree, but they add a lot of weight. This would influence handling some , I guess ?

 

[Jackson1320]

I agree, but they add a lot of weight. This would influence handling some , I guess ?

Probably not enough to notice

 

[Pierangiolo]

You can put together a twin turbo kit for half the price of a centrifugal kit if you know what you need

If you are referring to most turbo kits, they are all more expensive than centrifugal setups. The only turbo kit I can think of that is cheaper than a centrifugal setup is a single kit or an On3 kit but that may require some fab work to get fully installed.

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