time practice and class question

what is the difference between "time trials" and "timed practice" that i see on the new schedule?

also i have run with emra before and was never in the same class, i have a white 1988 merkur xr4ti that is modified, which class should i be in?

thanks

thanks for the clarification on the timed practice. as for the modifications here is a quick list:
engine mods:
minor porting of head,custom cam,solid lifters,rebuilt block with wiseco pistons,crower rods,60-1 turbo(running 18 psi),header,bigger intercooler,tec3 engine management.
suspension mods:
koni shocks/strut,upgraded springs,poly bushings throught,bigger front and rear swaybar, (frnt)mustang pbr 2piston brake calipers with 12" focus svt rotors, (rear) t-bird rear caliper conversion from drums, 215/45/16 kumho ecsta xs tires

the past couple times i went to the TT i was only running 7-8 psi, so i wasnt the quickest out there, but i definetly got more confidence. still working on some fine tuning with the tec3 but i think i will gradually increase boost this season to make sure i can put the power down and not drift the track

I would check with Bill Glitzgow but I would think ST1 or ST2.

You start in ST4 adn with the head work that is ST3, with the Turbo you are ST2 if you have suspension you are ST1 or higher. They put one last year in Tuner Over (TO) with me last year as well.

Bill can give you the definitive answer

in july i was in ST3 at limerock, and in the past either ST3,ST4 or TO

when i first built the engine, i put it on a dyno with the 7-8 psi until i broke it in. it made 290hp ant 306lb.ft. at the wheels, i made a couple changes and my estimation (based on others with similar setups)with 18-20 psi would be around 400-450 at the wheels. it is another animal once it goes past 12-15psi. i dont think i will run it with more than 15psi unless i fit bigger tires,lsd, and roll cage. i would rather have fun than concentrate on the times but the more time i spend on the track the more i want to modify to get faster, we will see how it goes

here are a couple pics