Sunday, November 15, 2009

Atom Tune & Dyno Results

We got the Atom back onto the K&N dyno after making all of our tweaks to the powertrain and ECU. This was the dyno that originally revealed two years ago that my stock Atom was making 260hp at the crank. We could now test it on the same dyno and find out if we made any true gains.

We've been blogging about the mechanical upgrades we have been making to my Atom. You can see these posted in previous months on this Blog. The following items were changed:
  1. Smaller pulley & belt
  2. Larger injectors
  3. Intake
  4. IC radiator - inline with original
  5. ECU Tune with 7100 redline for 91 octane
All other powertrain internals
remained the same. Our partnership with Secant was key since they are Ecotec experts with the ability to properly tune the stock ECU. This allowed significant changes to the poor tune that came with our cars. We know that many Atoms are blowing up exhaust systems - an issue incorrectly attributed to poor quality exhausts. As it turns out the EGTs were out of control and annihilating exhausts thx to the poor tune and mechanical configuration.

The Secant team was able to achieve 280hp & 241 ft-lbs of torque with this engine in their Lotus powertrain swap. This is the safe limit for a track driven, stock LSJ engine with 91 octane. People have achieved more but at the expense of powertrain reliability. I wanted to sort a package that could be run reliably, on the track, without the headache of frequent engine rebuilds.

We hoped to achieve the same power levels that Secant sorted with the Lotus. As it turns out, we nailed it. Three runs were taken at K&N and realized Horsepower of 278-281 (stock 262) & Torque of 240-248 (stock 229). This was with 91octane - we know with
race gas, more can be achieved.
A key part of the tune is the smooth power delivery from down low all the way to 7100rpm. The original tune showed a serious dip in power from 2500-3500 - this was eliminated with Secant's tune. The higher rpm limit also helps tweak out some additional power though the new tune makes more power everywhere. The car felt faster and now the dyno confirms it!

One interesting aspect of Secant's Atom tune is the changes to the lower rpm pedal progression. The original tune created a car that was very jumpy in around town driving at lower speeds. We've all had to endure slipping the clutch to get the Atom to drive smoothly at slow speed. The magic of comprehensive ECU tuning allows the tuner to 'slow down' the pedal at the low speeds and make it much easier to drive. You can also drive the car at slow speeds with no input to the accelerator - something Steve called 'Paddock Mode'. In fact we got stuck in a traffic jam where I was able to use this 'mode' to its fullest.

Contact us if you want your Atom tuned to deliver a safe level of power. We can supply all of the mechanical parts to get your Atom to run safely. And now, we have the data that shows we make real and safe power!

My friend, Jerry, the owner of K&N, invites our local car club to visit his huge facility for a yearly visit. I want to thank him and his gracious staff for the great tour of their business. K&N has a significant R&D lab that flow bench tests all their products and conducts serious MAF trials. These guys are definitely in a different league compared to their CAI competition. Naturally our intake features a K&N filter!

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