Supercharger Throttle Lag?

[HachiEnam]

Sorry if this question has been asked before but I couldn't find it anywhere.

Anyways, whenever people are comparing superchargers to turbochargers people who prefer superchargers do so because of linear power delivery and throttle response. The question is, shouldn't superchargers also hamper throttle response? After all, it is belt driven and the added mass needed to spin the supercharger would practically negate the benefits of a lightened flywheel or light weight crank pulley.

[xsnapshot]

Originally Posted by HachiEnam

Sorry if this question has been asked before but I couldn't find it anywhere.

Anyways, whenever people are comparing superchargers to turbochargers people who prefer superchargers do so because of linear power delivery and throttle response. The question is, shouldn't superchargers also hamper throttle response? After all, it is belt driven and the added mass needed to spin the supercharger would practically negate the benefits of a lightened flywheel or light weight crank pulley.

There is no lag for me. At least not with the JRSC. The power is instant and basically just feels like a bigger motor. Now it's not quite positive displacement supercharger torque, but it's plenty and there is definitely no lag.

In fact the throttle is almost a little too sensitive now. I have to get used to driving it. I've had Moto-Mike scale back the throttle sensitivity some to help.

[86fun]

I am curious about this too. It sure would be interesting to compare the ECU logs from two similarly powered Turbo/Supercharged 86's.. a run from 2k RPMs to redline at WOT. You could plot, time, engine RPM, vehicle speed, MAP, etc and actually come up with a measureable and comparable "throttle response" view.

[kch]

Originally Posted by HachiEnam

Sorry if this question has been asked before but I couldn't find it anywhere.

Anyways, whenever people are comparing superchargers to turbochargers people who prefer superchargers do so because of linear power delivery and throttle response. The question is, shouldn't superchargers also hamper throttle response? After all, it is belt driven and the added mass needed to spin the supercharger would practically negate the benefits of a lightened flywheel or light weight crank pulley.

I think they're more talking about the instant, always-on boost you get with a SC, rather than having to wait for the turbo to spool.

[wbradley]

I have a lightened pulley which might partially compensate.

In the case of the HKS centrifugal unit, it is virtually identical to the Rotrex unit EXCEPT that one of the 3 internal rollers, (which act as gears except they can slip under low load,) is spring loaded and really slips at lower RPMs so in fact there is minimal added load until the revs are up a bit, maybe in the 3000 RPM range. This is to reduce parasitic power loss and improve fuel economy, but I believe it also minimizes throttle response latency.

[CSG Mike]

Originally Posted by HachiEnam

Sorry if this question has been asked before but I couldn't find it anywhere.

Anyways, whenever people are comparing superchargers to turbochargers people who prefer superchargers do so because of linear power delivery and throttle response. The question is, shouldn't superchargers also hamper throttle response? After all, it is belt driven and the added mass needed to spin the supercharger would practically negate the benefits of a lightened flywheel or light weight crank pulley.

There is no lag, because the piping is always pressurized.

[CSG Mike]

Originally Posted by 86fun

I am curious about this too. It sure would be interesting to compare the ECU logs from two similarly powered Turbo/Supercharged 86's.. a run from 2k RPMs to redline at WOT. You could plot, time, engine RPM, vehicle speed, MAP, etc and actually come up with a measureable and comparable "throttle response" view.

Where's the throttle response, if you're WOT from 2k rpm to redline?

Throttle response is the delay, or lack thereof, from when you step on the gas to when the engine responds with output.

[HachiEnam]

What about the rate the rev climbs or falls? Is there any difference?

[Yobiwan]

http://www.datazap.me/u/yobiwan/sc9?...0&zoom=520-737
http://www.datazap.me/u/yobiwan/42mm...zoom=1124-1298

I'm using HKS v2 s/c . and almost no lag for me too.
About the rate, I don't feel any difference when climbs, but I think it's faster when falls.

[sw20kosh]

None.

[86fun]

Originally Posted by CSG Mike

Where's the throttle response, if you're WOT from 2k rpm to redline?

Throttle response is the delay, or lack thereof, from when you step on the gas to when the engine responds with output.

If you had them all plotted over time you could see how long it would take to make a certain amount of power after the throttle went to WOT. Ok, so you don't have to go to redline... unless one was REALLY laggy! heh.


On a dyno you don't get to see throttle plotted with the power, so not able to get it there, but I'm sure you can figure out roughly the power level from other ECU prameters.


Now that I think of it, the dyno shop I use just got WinPep 8 setup which has an OBD connector and can log all the OBD stuff. Maybe when I get the Edelbrock setup dyno'd I'll see if I can have it added...

[stevo585]

Well lets be honest under about 4k centrifugals don't make much boost. Above 5k is where they take off. Granted in first or second gear it will probably feel instant.

[CSG Mike]

Originally Posted by HachiEnam

What about the rate the rev climbs or falls? Is there any difference?

Climbing is based on engine output. Falling would be faster on a SC car, theoretically, out of gear. In gear, no realized difference.

[CSG Mike]

Originally Posted by stevo585

Well lets be honest under about 4k centrifugals don't make much boost. Above 5k is where they take off. Granted in first or second gear it will probably feel instant.

That depends purely on setup. The same could be said about turbos; the boost threshold is determined by setup.