Looney Tuning
05-04-2009, 06:42 PM
This Evo X GSR belongs to Evo Ippo’s friend. The car had the following mods:
Megan DownPipe
Hks Hi-Power Exhaust,
Custom Intercooler pipe Kit
Custom Intake Kit
Custom test Pipe
Voodoo MBC (piece of crap that was replaced with an HKS EBC)
The story of this tune is to pick the right MBC. Evo Ippo wanted to install an HKS EBC to tune the car. But I read that EBCs are causing CEL on the Evo X. Given the great results I got with the Dejon Tool on an Evo X that I tuned, I advised him to go with an MBC. He did get an MBC, but it turned out to be a turd. I should not have listened to the stories of EBCs triggering a CEL, because the HKS EBC did not trigger any. It is one solid EBC.
With the Voodoo MBC, the boost would peak at 25 psi and then will fall to 20 psi 300 rpm later. Take a look at the overlay between the boost curve by the voodoo and the boost curve by the HKS EBC. The dotted line is the voodoo.
http://www.sr20deracing.com/EVO/Vu_10/boost_overlay.gif
I could not get the exact match between the RPMs for the overlay, but you can get the general idea of what is going on here. The Voodoo MBC peaks and then falls flat on its face, whereas the HKS EBC peaks and holds the boost and then slowly tapers to redline.
Here are the 3D boost tables for the Voodoo MBC and the HKS EBC. All charts are an average of 3-4 back to back WOT 4th gear runs. You will notice similar behavior to the chart above. The MBC (1st chart) hits peak boost @ 25.90 psi and then immediately falls to 20.97 psi by 4000 rpm. Thereafter, boost holds steady and tapers to 18.19 psi by redline.
http://www.sr20deracing.com/EVO/Vu_10/Boost_mbc_ebc.gif
By contrast, the HKS EBC peaks at 26.10 psi and holds at 24.xx psi to 4500 rpm. By 5000 rpm the EBC boost is ~1.5 psi higher than the MBC boost. The HKS maintains its higher boost to 6500-7000 rpm where the boost between the MBC and the EBC is almost the same.
This Evo had an open element intake as well as the factory reflash. The “stock” AFR, therefore, was not as rich as the other Evo Xs that I have logged. The AFR never fell into the 9.xx:1 ratio. I simply leaned out the car by about 1-0.75 AFR points up to 5000 rpm and by about 0.5-0.25 AFR points all the way to redline.
http://www.sr20deracing.com/EVO/Vu_10/afr_b4_after.gif
Finally here are the before and after power charts. Please note that the base power chart was not on the stock boost since the car had an MBC that reduced the taper of the stock boost. The power gains, therefore, are less than what you would expect on a car with stock boost.
http://www.sr20deracing.com/EVO/Vu_10/dyno_b4_after.gif
The inability of the Voodoo MBC to hold boost is reflected in the base power chart. The torque curve with the MBC is much lower than that with the EBC despite the same peak of ~26 psi. That is because the MBC falls on its face a mere 300 RPM following peak boost.
There are gains across the entire power curve. The largest gain in the area under the curve was as follows:
31 hp gain from 6000 to 6500 rpm
42 ft-lb gain from 3500 to 4000 rpm
The rest of the gains are noted on the chart
Megan DownPipe
Hks Hi-Power Exhaust,
Custom Intercooler pipe Kit
Custom Intake Kit
Custom test Pipe
Voodoo MBC (piece of crap that was replaced with an HKS EBC)
The story of this tune is to pick the right MBC. Evo Ippo wanted to install an HKS EBC to tune the car. But I read that EBCs are causing CEL on the Evo X. Given the great results I got with the Dejon Tool on an Evo X that I tuned, I advised him to go with an MBC. He did get an MBC, but it turned out to be a turd. I should not have listened to the stories of EBCs triggering a CEL, because the HKS EBC did not trigger any. It is one solid EBC.
With the Voodoo MBC, the boost would peak at 25 psi and then will fall to 20 psi 300 rpm later. Take a look at the overlay between the boost curve by the voodoo and the boost curve by the HKS EBC. The dotted line is the voodoo.
http://www.sr20deracing.com/EVO/Vu_10/boost_overlay.gif
I could not get the exact match between the RPMs for the overlay, but you can get the general idea of what is going on here. The Voodoo MBC peaks and then falls flat on its face, whereas the HKS EBC peaks and holds the boost and then slowly tapers to redline.
Here are the 3D boost tables for the Voodoo MBC and the HKS EBC. All charts are an average of 3-4 back to back WOT 4th gear runs. You will notice similar behavior to the chart above. The MBC (1st chart) hits peak boost @ 25.90 psi and then immediately falls to 20.97 psi by 4000 rpm. Thereafter, boost holds steady and tapers to 18.19 psi by redline.
http://www.sr20deracing.com/EVO/Vu_10/Boost_mbc_ebc.gif
By contrast, the HKS EBC peaks at 26.10 psi and holds at 24.xx psi to 4500 rpm. By 5000 rpm the EBC boost is ~1.5 psi higher than the MBC boost. The HKS maintains its higher boost to 6500-7000 rpm where the boost between the MBC and the EBC is almost the same.
This Evo had an open element intake as well as the factory reflash. The “stock” AFR, therefore, was not as rich as the other Evo Xs that I have logged. The AFR never fell into the 9.xx:1 ratio. I simply leaned out the car by about 1-0.75 AFR points up to 5000 rpm and by about 0.5-0.25 AFR points all the way to redline.
http://www.sr20deracing.com/EVO/Vu_10/afr_b4_after.gif
Finally here are the before and after power charts. Please note that the base power chart was not on the stock boost since the car had an MBC that reduced the taper of the stock boost. The power gains, therefore, are less than what you would expect on a car with stock boost.
http://www.sr20deracing.com/EVO/Vu_10/dyno_b4_after.gif
The inability of the Voodoo MBC to hold boost is reflected in the base power chart. The torque curve with the MBC is much lower than that with the EBC despite the same peak of ~26 psi. That is because the MBC falls on its face a mere 300 RPM following peak boost.
There are gains across the entire power curve. The largest gain in the area under the curve was as follows:
31 hp gain from 6000 to 6500 rpm
42 ft-lb gain from 3500 to 4000 rpm
The rest of the gains are noted on the chart