Does the variable cam timing play a role in this?

 

I believe the vari cam timing is a function of the RPM not the other way around.

 

right. for me, can't comment on flywheels or e-gas, but i did notice same feeling the first time i drove a 911 (2000MY). the throttle response was strangely mechanical, and when combined with the terrible std shifter, i was pretty shocked by how unsmooth the car felt- compared to my bmw's. the slick 6-speed coupled with the throttle response of the inline 6 in my 330 ZHP feels like my drivetrain is encased in warm butter-- super, silky smooth all the way to the redline. even with my new SSK which vastly improved everything, i can't say my 911 drivetrain is smooth. although, of course, it's way more fun.

 

throttle response on my e46 m3 was definitely more instant than my c4s

those six computer controlled throttle bodies is insanely sweet and the inline 6 is butter smooth

 

put an evo cai, exhaust, and a flash... then a LWF. Now were talking, problem solved

 

Throttle response is great on my '99 Cab, and on my wfe's '99 Boxster as well. It feels like the throttle cable is hooked directly to the back tires like it should.

For those that don't know, throttle response means INSTANTANEOUS and IMMEDIATE response from the motor as the throttle or gas pedal is pressed. No momentary lag or millisecond waiting for things to happen.

 

LWF is not for those people who were changing their clutch pedal assist springs last week, though, in an attempt to not stall out in 1st gear. :-)

Bill

 

I noticed that as well, the M3 revs quicker than our cars. But the M3 also has a lame exhaust note to go with the revs! Stock vs stock, the P's exhaust puts the M3 to shame.

Anyone tried revving the rotary engine in a RX7 or Rx8? Those things rev even quicker, like a 2-stroke motorcycle!

 

Probably the fact that there's hardly any intake valve lift at low RPMs (for economy) and the car has a 900 lb. flywheel.

 

+1 A light weight flywheel will cure that.

 

Don't forget there is real throttle response and fake throttle response. It's easy to change the mapping between the pedal and the throttle body(s) to make the car feel like it's reving faster because for a given amout of pedal input you get more input at the throttle. That was a favorite trick on older cars. Just change the throttle cable cam on the throttle body or carb and the owner thinks the car is a rocket ship. "I barely touch the gas and the car revs like crazy." Porsche does the same thing with the "sports tuning" on the new cars.
Jim

 

but Jim, there is no gimmick to the M3's throttle response mechanics.

again it's got six individual throttle bodies controlled by their M ecu. it's awesome. now the sport mode is a bit gimmicky because it makes the car almost too touchy.

 

So there's no gimmick unless it's in sport mode?

Older BMs without electronic throttle had complicated linkages on the throttle
body to alter the shape of the opening curves. That is a gimmick and I'd bet dollars
to donuts there's a huge amount of code in their modern ECUs to map those throttles in ways
we couldn't begin to guess here.

 

no there isn't because the real world result is it works GREAT in non-sport mode. throttle response is razor sharp. in sport mode, it's difficult to heel-toe because the throttle mapping is so aggressive a little input results in too much revs to the point where it's untenable. sport mode doesn't accomplish anything other than making a lot of owners who don't know or care to know think it's putting down more power and making them faster.

i agree on the ecu stuff and how it's out of reach of many to understand what's really going down... kinda like suspension tuning which really is black magic.

 

FWIW, I've always found the throttle response of any Motronic 911 to be like a lawn mower compared to the old Weber or MFI versions. I don't remember what the CIS cars were like.