Chippin' it

In august 1997, I went to Simco to get a new chip installed in my car. I didn't know quite what to expect to get out of the visit, but after talking to him on the phone, I had my hopes up.

As most of you already know, the 4A-GE is an 'unchippable' engine, or rather, it's CPU is. What Simco does is quite similar to what Superchips do with their I.C.O.N. system, i.e. they piggyback a new chip onto the existing one. Doing this, they can monitor many of the signals coming in from the sensors into the CPU, and alter the resulting commands going out from the CPU.

Below are some dyno charts recorded before and after the new chip was installed. Unfortunately, Simco's dyno was not behaving properly after being robbed of some of it's sensors by burgulars (!). Missing from the charts (and also not taken into consideration when calculating power) are air temperature, air pressure, intake air, rpms and torque. We'll be doing another run in the spring, to get a completely accurate chart. The charts we do have should be totally comparable against each other, though, as they were recorded with the same (incomplete) dyno. Just ignore the figures, but do take note of the difference between them on the charts...


This chart shows the cars performance before the new chip was installed. Note the dip in the curves between ~80 km/h and ~110 km/h, caused by the TVIS system kicking in at 4350 rpms.

This is with the new chip in place. Remember the dip I mentioned earlier? Gone. The curves are almost completely straight, with no loss of power anywhere in the powerband. Engine output is up by 5.5 kW (= ~7.5 hp).

This chart shows a run in 3rd gear (the two previous charts were in 4th gear), with a max power output of 89 kW, up by 10.5 kW (more than 14 hp) compared to the first chart.

Final results:


Engine output Wheel output Drag output
Original chip 78.5 kW 56.0 kW 22.5 kW
New chip (4th gear) 84.0 kW 61.0 kW 23.0 kW
New chip (3rd gear) 89.0 kW 70.0 kW 19.0 kW

In conclusion; the chip worked. What seems to have changed the most is the torque - 5th gear driving is no more a bothersome task, it seems to have much more grunt in the lower- and middle range than before. I like it. :-)

Last updated: 30.08.00