Hi, my brother owns a 1985 RX-7 gsl. (I own a mustang, and im not to knowlegable on these rotory engines) We ran the car at a track, and pulled off a 16.1@83.... this is not enough. What can be done to the engine, to run low 14's without going with a power adder (IE no turbo nor Nitrous) So far, the car has a long tube header, and high flow (no emmissions) exaust all the way out. The car also has an Electric fan, and the A/C has been removed. What can all of you experts recomend to help us make a 14.5 or better pass?

 

Heres what is done on the car so far.....

RB Header
RB Pre-Silencer
Removed Spring for Secondaries
K&N AirFilter
8.8 Accel Wires
Short Shifter- Mazdatrix
Carter Fuel Pump
RP Underdrive Pulleys
Black Magic Electric Fan
4.444 Ring & Pinion
13" PanaSport Rims
Mariah Mode 4 Bumper/Airdam
S/R Motorsport Guages
No A/C, ACV, AirPump, Tire and Jack

 

Their is no replacement for displacement.

The only thing Rotary Rex didn't mention was a lightweight flywheel. A 17lbs flywheel will greatly increase performance because of the weight decrease. Stock flywheel is almost 30lbs You can have the motor street ported. On a rotary, this increases the duration of the intake being opened, similar to changing the cam lobes on a piston engine. Click on the 2 links below to see how porting is done, and how the internals of a rotary work.

http://www.mazdatrix.com/faq/port6p.htm
http://www.howstuffworks.com/rotary-engine.htm

After you read the first one, you should be able to look at the second one and picture how the increase in the size of the port will allow it to be open longer and allow more air/fuel into the rotor.

 

Hey Rotary-rex, how much did you pay for your short shifter from mazdatrix? It says $260ish...FOR A SHORT SHIFTER??????? G E E Z PHEW.....!!!!

 

when i bought the short shifter, i payed 202.00 including tax. Maybe they jacked up the price. I heard something about modding the length of the stock one, but this wont change the real thing that matters, that being the length of the pivot ball.. 202.00 was a hight price, i cant imagine paying 260.00!! Rotary-Rex

 

We can tell its x-mas time.. This is a very common post.

About $12k , see sig

 

Rather then take the 2ndary spring out, I'd go straight to the mechincal 2ndary mod. ITs far more precise to the feel for the driver with only one minor drawback-slight accerator pump hesitation. I have experimented with other peoples 12a's still using the stock crap nikki carb and found that shorting or removing the spring doesn't help and feels really impricise.

I honestly would get rid of the stock carb and go to a sidedraft carb, or downdraft carb, Lakecities intake and sidedraft carb, or a holley racing beat kit.

And for sure the lightweight steel flywheel!

 

Rebuild the engine with a nice bridge-port, add a decent carby, tune it and that should see you into the 13's/low 14's.

 

Add lightness to the car... you don't REALLY need a passenger seat, or carpet, or sound deadening material, or a dash, or, or, or.....

 

Why can't you use boost or nitrous oxide? Is it the class you are racing in, budget, or you just want simplicity?