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View Full Version : Mid Month Tune: +51 hp and +42 ft-lb



Looney Tuning
08-14-2009, 03:05 PM
This Evo X GSR belongs to a non-forum member. This is the car that had a malfunctioning fuel pump relay. As I mentioned in my previous post on the subject, the owner was able to diagnose and fix that problem. The car had the following minimal modifications:

HKS drop-in filter
Invidia N1 single cat-back exhaust
Wastegate arm adjusted three turns (did absolutely nothing to hold/increase boost)

We hook up the logging equipment, download the ECU and set it up for mode23 logging, and flash it back into the ECU. Before logging at WOT, we logged the fuel trim at cruise to see if the HKS drop-in has any serious impact on the trim and thus AFR at WOT. It DID NOT. The cruise trim fluctuated between 0-3% after logging them from ~45 minutes. If you are looking for a drop-in that does not affect the trims, then this one is it.

After checking the trims, we go out to the logging site and run 3 back-to-back WOT 4th gear runs. Here are the results starting with the boost profile:

http://www.sr20deracing.com/looneytuning/Evo/Isaac/psi_b4_after.gif

The peak stock boost was 22.79 psi tapering to 15.24 psi. This is very typical of stock boost on stockish Evo Xs, indicating that the wastegate arm adjustment did little to improve the boost profile over stock.

Not only was the tuned boost 1.45 psi higher than stock boost at peak, it also came on 750 rpm earlier. Furthermore, the boost held to 19.22 psi by redline, a 3.98 psi increase over the stock boost by redline.

The tuned AFR was also a huge contrast with the stock AFR. At peak stock boost the AFR was a low 9.58:1, went to a low 9.51:1 by 4500 rpm and ended up slightly higher at 9.73:1 AFR by redline. The tuned AFR, by contrast, was 1.24 points leaner at peak boost, 1.54 points leaner at 4500 rpm, and 1.55 points leaner by redline.

http://www.sr20deracing.com/looneytuning/Evo/Isaac/afr_b4_after.gif

The best way to illustrate the differences between the stock and tuned boost and AFR profiles is to overlay the charts on top of each other:

http://www.sr20deracing.com/looneytuning/Evo/Isaac/boost_afr_overlay.gif

The dotted lines are the tuned profile and the solid lines are the stock profile. You will note that the boost gains between ~3200 rpm and ~4000 rpm are not as beefy as the boost gains between from ~4500 rpm all the way to redline. The boost gain in the boost curve is simply very beefy. The AFR gains are pretty much consistent from ~4600 rpm all the way to redline.

As usual on our crappy 91 octane, I had to back off the timing to prevent knock. There is simply no need for firing the spark that far ahead of BTDC when you have a lean mixture. A lean mixture burns faster than a rich mixture and does not require the stock like timing advance that Mitsu was running when the AFR was 9.8-9.5:1.

http://www.sr20deracing.com/looneytuning/Evo/Isaac/tim_b4_after.gif

The tuned timing was 4-5* lower than stock at peak boost, 3-4* lower than stock in the mid range (4500-5500 rpm), 6-9* lower than stock at the top of the rpm range (6000-7000 rpm). Any timing advance above these numbers triggered more than 2 counts of knock, which was not acceptable to me. I usually tune for 1-2 counts of knock.

Finally, here are the overlaid power charts indicating the gains. As always, the power gain is all that matter; peak numbers mean absolutely nothing. If I was king of the dyno world, then I will not allow a dyno sheet to be posted w/o a baseline. I will go further and ban peak numbers from being published; only gains will be indicated on dynos in my kingdomÂ* O0 :grin: :D

The car recorded the following gains:

Peak power gain: +48 hp
Max power gain: +51 hp

Peak torque gain: +25 ft-lb
Max torque gain: +42 ft-lb

The hp gains are mostly concentrated above 4500 rpm, while the torque gains are all across the power curve. I am very happy with the way this car turned out. We started with faulty relay that ran the car lean on the stock tune and ended up with 51 hp and 38-42 ft-lb of gain; a very happy endingÂ* :smitten:

fusionchicken
08-22-2009, 05:05 AM
win!!!

big boss
08-24-2009, 04:08 AM
DUDE O0 great JoB Naji