sounds like you inadvertently did a poor man's tune up.

 

http://www.zspecialties.com

 

A poor man’s tune up is necessary on most Z’s. Choose your road carefully to do this. The poor man’s tune up applies to both manual and automatic transmission vehicles. Find a fairly straight road or freeway on-ramp and take off in your Z. If you have an automatic then lock it in first. Mash the gas pedal all the way to the floor, take the engine up to 5500 rpm, then shift into second and mash the gas pedal all the way to the floor again taking it up to 5500 rpm. When the rpm gets up to about 4500 in both gears, take a quick glance in your rear view mirror and look to see if your car is blowing out brown or black exhaust smoke. If it is then you just did a world of good for your engine by cleaning out buildup from driving too slow. The proper way to do this is with a full load on the engine and higher rpms. It is that combination that produces the proper results. After this, you can resume normal driving.

Steve.....Add one of these.....it'll stop that body roll. Futofab has 'em.

sounds like you inadvertently did a poor man's tune up.

 

http://www.zspecialties.com

 

A poor man’s tune up is necessary on most Z’s. Choose your road carefully to do this. The poor man’s tune up applies to both manual and automatic transmission vehicles. Find a fairly straight road or freeway on-ramp and take off in your Z. If you have an automatic then lock it in first. Mash the gas pedal all the way to the floor, take the engine up to 5500 rpm, then shift into second and mash the gas pedal all the way to the floor again taking it up to 5500 rpm. When the rpm gets up to about 4500 in both gears, take a quick glance in your rear view mirror and look to see if your car is blowing out brown or black exhaust smoke. If it is then you just did a world of good for your engine by cleaning out buildup from driving too slow. The proper way to do this is with a full load on the engine and higher rpms. It is that combination that produces the proper results. After this, you can resume normal driving.

More like a common sense blowing out the soot.  A "poor man's tune up" is done on the side of the road to get home. 

...After this, you can resume normal driving.

who wants to resume normal driving after that??

...unless you spy LLE in the rearview...

that all depends on what you consider normal driving  ::

 If you drive a Z, there are 2 types of driving, normal & restrained. I think, after the "tune-up", you're supposed to resume restrained driving.    Yeah right.

A puff of smoke at 90mph? With a full load on the engine and high rpm I wouldn't worry much. Most cars I see on the track that are carbureted have some or light puffs here and there under full throttle. Especially the heavily modified csrs6 <==== (****in auto correct ) I meant "cars"

Edited March 24, 201510 yr by 71Nissan240Z