Street Modified Evo Build – ACD Tuning Review
Mar 27, 2012, 07:09 PM
#1
Street Modified Evo Build – ACD Tuning Review
Back Story:
Since I’m fairly new to the motorsports forum compared to most here, I figured a little background on myself is in order. I started autocrossing back in 2004 in a basically stock B15 sentra. The bug bit hard and I started to modify the car and experiment with suspension s etups and power modifications. Eventually the car made it to street modified class with a turbo setup, a lot of custom suspension pieces, and a lot of people wondering why anyone would put so much time into a sub-par platform. The last year I ran the car was the first year for SMF, which is another class the sentra was not “the car to have” in, being a heavy fwd sedan. I eventually found myself in a financial position to move on to a better platform… enter my 2006 Evo MR. I bought the car in December 2010 and ran it all last year with a basic setup. I won the Philadelphia region SM class championship and did fairly well with it at a Pro Solo and National Tour, considering the mods and time behind the wheel.
2011 NJ Pro -
2012 Season:
At the end of last year, I decided it was time to go for the “big show.” I talked with a friend of mine who was running his Evo 8 in BSP (Mr. MR on the forum), and we decided to join forces and build a proper Street Modified evo. Without going into all the details, I’ll just say the car is now on a proper suspension, E85 is in the tank, and there’s a little aero going on
To help with this build, I sought out a few sponsors to help with key upgrades to the car. One of these sponsors was ACD-Tuning. With all the work going into making this car handle extremely well, I wanted every edge I could get over the competition.
I had been reading a few threads on here and some background into the effects of the ACD computer, and how it was possible to change the reaction of the ACD to different driving conditions. A lot of people were using “out of the box” products for street driven or mildly autox’d evos, but our car was not going to fall in those categories. I contacted Matt at ACD-Tuning and we started talking about his product options. He recommended a custom tune on my car that he could tailor to the setup and conditions. With the first outing for the car being a test and tune session mid March, Mike and I focused on getting the car assembled and ready to run. Matt showed up with his tuning tools in hand at the test and tune, and we went to work.
The first order of business was to make all the new parts on the car work well together. We spent the morning on the skid pad and short autox course (slalom and transition heavy) tuning the compression and rebound settings on the car, and making sure we were happy with the alignment and spring rates. I took the very first run out in the car and kept it conservative. We were on cold hoosiers in a car that was untested, so kept the dial at about 7 and put in an oversteer prone run. A few setting tweaks and it was time for Mike’s first run. We made it to turn 3 before the rear stepped out and we ended in the grass. The good news was the brand new splitter was impact tested and passed! We also got paid for cutting the grass.
By the end of the morning the car was feeling good. We got the suspension dialed to where it felt best, and it was time to see what this ACD tuning thing was all about. One of the things that felt off on the car was the front did not have the sharp turn in we were expecting. During our lunch break, Matt loaded three custom programs into the ACD computer. Tarmac was the “mildest” of the programs, and they got more aggressive as we moved to gravel and then snow. The idea was for us to do back to back to back runs on each setting and see what we liked best. Then we would keep or tweak that one and be good to go (it turns out we liked all three for different conditions).
Since we had downtime over lunch, the hoosiers cooled back off. We started the first pair of runs (one for me and one for Mike) in tarmac mode. Instantly we noticed a difference in the slaloms. The front turned in better and the back was more responsive to throttle. Neither Mike nor myself left foot brake, so ideally the car will tuck the nose and rotate off throttle and the back will slightly, but controllably, step on throttle. I was surprised at how easy the car felt to slalom that first run out. The afternoon course was basically a kinked slalom on the way out, a 180 degree turn around, and then high speed offsets on the way back (airport location). At the turnaround, the car rotated nicely as I rolled on the throttle on exit. The car has always rotated on power due to the rebuilt rear diff, so this corner exit was a familiar feeling for us. The big difference was the slalom and the high speed transitions. Any time I was coming off throttle to tuck the nose in and then transitioning back on to throttle to rotate the car, I could feel a difference in the car’s behavior. It was doing more of what I wanted it to do!
After Mike’s turn on tarmac mode, the tires were getting heat in them again and the sun was coming out. We bumped to gravel mode and went at it again. This time the car had much more grip from the warmer tires and surface, and the more aggressive ACD mode was really noticeable. It was doing what we felt in tarmac mode, but more exaggerated. Turn in was even better, and while on throttle oversteer was not new with the tuning, it did feel more controllable. I’ve always described to folks the feeling of a stock ACD tuned evo with the rear diff rebuilt as the following: The 50:50 center diff would cause the front tires to push a little as power was applied on corner exit. Then the center diff would lock and the rear would come around. The rear diff rebuild was a world of difference over stock, but that initial push could still be noticed. With the ACD-Tuning magic working, that initial push was greatly reduced, to the point where I wouldn’t even pay attention to it anymore.
On my third and fourth runs, I used snow mode (the most aggressive custom tune) and loved it. By this time the surface temp was warm enough that we were getting lots of grip from the hoosiers. This map was not as noticeable of a difference from gravel as gravel was from snow, but there was still a change in how fast the center diff locked and unlocked, allowing the car to tuck the nose and then step the rear out. Again, the most notice change was in slalom behavior, were throttle modulation is key in getting through smoothly and quickly. Tuck the nose, squeeze the throttle to the next cone, tuck the nose, repeat. The key is when you can squeeze the throttle, and with the turn in we were getting off throttle I was rolling back in much earlier than I could before the ACD was modified.
At the end of the day, we were very happy with the results of the ACD Tuning modifications. We discussed the attributes of each map and what we felt throughout the afternoon, and finally decided we wanted to keep all three maps. The tarmac map was perfect for lower grip situations. Rain, cold, first runs on cold tires, etc. As surface grip and temps increased, we wanted the ability to bump up in steps to the most aggressive settings. Snow would be reserved for high grip surfaces like the runway we were on in warm weather. The gravel setting is likely were we will be on asphalt and medium grip surfaces. The beauty of the system is all the maps are there. All we need to do is push the ACD button to get what we want, so now we have the ability to tweak the suspension and the ACD to get the desired car behavior for any given condition.
First Event:
The first event of the Philly region was this past Sunday. Mike and I knew the turn in of the car was good with the results from the tnt, but could be better with a couple suspension tweaks. We lowered the front a bit and spent some quality time with a level floor, strings, a camber gauge, and some wrenches. With the new ride height and alignment done, the car was loaded and we went cone hunting. The day was cool and it had rained over night. The course was wet in the morning. It dried up a decent amount after the first heat, but it still had damp spots when we ran second heat. We kept the car in tarmac for the day due to the lower grip. Below are some videos from the event. I will say the day was 0.053 seconds from perfect… Mike took first in class and PAX, and I ended up that 0.053 behind him in second in class and PAX! The car was an absolute blast to drive, and the season is off to a great start. We’re headed to the DC Pro in a few weeks, where we get to run against the amazing 240 of PJ Corrales and David White.
Pictures -
Since I’m fairly new to the motorsports forum compared to most here, I figured a little background on myself is in order. I started autocrossing back in 2004 in a basically stock B15 sentra. The bug bit hard and I started to modify the car and experiment with suspension s etups and power modifications. Eventually the car made it to street modified class with a turbo setup, a lot of custom suspension pieces, and a lot of people wondering why anyone would put so much time into a sub-par platform. The last year I ran the car was the first year for SMF, which is another class the sentra was not “the car to have” in, being a heavy fwd sedan. I eventually found myself in a financial position to move on to a better platform… enter my 2006 Evo MR. I bought the car in December 2010 and ran it all last year with a basic setup. I won the Philadelphia region SM class championship and did fairly well with it at a Pro Solo and National Tour, considering the mods and time behind the wheel.
2011 NJ Pro -
2012 Season:
At the end of last year, I decided it was time to go for the “big show.” I talked with a friend of mine who was running his Evo 8 in BSP (Mr. MR on the forum), and we decided to join forces and build a proper Street Modified evo. Without going into all the details, I’ll just say the car is now on a proper suspension, E85 is in the tank, and there’s a little aero going on
To help with this build, I sought out a few sponsors to help with key upgrades to the car. One of these sponsors was ACD-Tuning. With all the work going into making this car handle extremely well, I wanted every edge I could get over the competition. I had been reading a few threads on here and some background into the effects of the ACD computer, and how it was possible to change the reaction of the ACD to different driving conditions. A lot of people were using “out of the box” products for street driven or mildly autox’d evos, but our car was not going to fall in those categories. I contacted Matt at ACD-Tuning and we started talking about his product options. He recommended a custom tune on my car that he could tailor to the setup and conditions. With the first outing for the car being a test and tune session mid March, Mike and I focused on getting the car assembled and ready to run. Matt showed up with his tuning tools in hand at the test and tune, and we went to work.
The first order of business was to make all the new parts on the car work well together. We spent the morning on the skid pad and short autox course (slalom and transition heavy) tuning the compression and rebound settings on the car, and making sure we were happy with the alignment and spring rates. I took the very first run out in the car and kept it conservative. We were on cold hoosiers in a car that was untested, so kept the dial at about 7 and put in an oversteer prone run. A few setting tweaks and it was time for Mike’s first run. We made it to turn 3 before the rear stepped out and we ended in the grass. The good news was the brand new splitter was impact tested and passed! We also got paid for cutting the grass.
By the end of the morning the car was feeling good. We got the suspension dialed to where it felt best, and it was time to see what this ACD tuning thing was all about. One of the things that felt off on the car was the front did not have the sharp turn in we were expecting. During our lunch break, Matt loaded three custom programs into the ACD computer. Tarmac was the “mildest” of the programs, and they got more aggressive as we moved to gravel and then snow. The idea was for us to do back to back to back runs on each setting and see what we liked best. Then we would keep or tweak that one and be good to go (it turns out we liked all three for different conditions).
Since we had downtime over lunch, the hoosiers cooled back off. We started the first pair of runs (one for me and one for Mike) in tarmac mode. Instantly we noticed a difference in the slaloms. The front turned in better and the back was more responsive to throttle. Neither Mike nor myself left foot brake, so ideally the car will tuck the nose and rotate off throttle and the back will slightly, but controllably, step on throttle. I was surprised at how easy the car felt to slalom that first run out. The afternoon course was basically a kinked slalom on the way out, a 180 degree turn around, and then high speed offsets on the way back (airport location). At the turnaround, the car rotated nicely as I rolled on the throttle on exit. The car has always rotated on power due to the rebuilt rear diff, so this corner exit was a familiar feeling for us. The big difference was the slalom and the high speed transitions. Any time I was coming off throttle to tuck the nose in and then transitioning back on to throttle to rotate the car, I could feel a difference in the car’s behavior. It was doing more of what I wanted it to do!
After Mike’s turn on tarmac mode, the tires were getting heat in them again and the sun was coming out. We bumped to gravel mode and went at it again. This time the car had much more grip from the warmer tires and surface, and the more aggressive ACD mode was really noticeable. It was doing what we felt in tarmac mode, but more exaggerated. Turn in was even better, and while on throttle oversteer was not new with the tuning, it did feel more controllable. I’ve always described to folks the feeling of a stock ACD tuned evo with the rear diff rebuilt as the following: The 50:50 center diff would cause the front tires to push a little as power was applied on corner exit. Then the center diff would lock and the rear would come around. The rear diff rebuild was a world of difference over stock, but that initial push could still be noticed. With the ACD-Tuning magic working, that initial push was greatly reduced, to the point where I wouldn’t even pay attention to it anymore.
On my third and fourth runs, I used snow mode (the most aggressive custom tune) and loved it. By this time the surface temp was warm enough that we were getting lots of grip from the hoosiers. This map was not as noticeable of a difference from gravel as gravel was from snow, but there was still a change in how fast the center diff locked and unlocked, allowing the car to tuck the nose and then step the rear out. Again, the most notice change was in slalom behavior, were throttle modulation is key in getting through smoothly and quickly. Tuck the nose, squeeze the throttle to the next cone, tuck the nose, repeat. The key is when you can squeeze the throttle, and with the turn in we were getting off throttle I was rolling back in much earlier than I could before the ACD was modified.
At the end of the day, we were very happy with the results of the ACD Tuning modifications. We discussed the attributes of each map and what we felt throughout the afternoon, and finally decided we wanted to keep all three maps. The tarmac map was perfect for lower grip situations. Rain, cold, first runs on cold tires, etc. As surface grip and temps increased, we wanted the ability to bump up in steps to the most aggressive settings. Snow would be reserved for high grip surfaces like the runway we were on in warm weather. The gravel setting is likely were we will be on asphalt and medium grip surfaces. The beauty of the system is all the maps are there. All we need to do is push the ACD button to get what we want, so now we have the ability to tweak the suspension and the ACD to get the desired car behavior for any given condition.
First Event:
The first event of the Philly region was this past Sunday. Mike and I knew the turn in of the car was good with the results from the tnt, but could be better with a couple suspension tweaks. We lowered the front a bit and spent some quality time with a level floor, strings, a camber gauge, and some wrenches. With the new ride height and alignment done, the car was loaded and we went cone hunting. The day was cool and it had rained over night. The course was wet in the morning. It dried up a decent amount after the first heat, but it still had damp spots when we ran second heat. We kept the car in tarmac for the day due to the lower grip. Below are some videos from the event. I will say the day was 0.053 seconds from perfect… Mike took first in class and PAX, and I ended up that 0.053 behind him in second in class and PAX! The car was an absolute blast to drive, and the season is off to a great start. We’re headed to the DC Pro in a few weeks, where we get to run against the amazing 240 of PJ Corrales and David White.
Pictures -
Last edited by psushoe; Mar 28, 2012 at 05:44 PM.
Mar 27, 2012, 07:17 PM
#2
Videos from first event:
My fastest run with in car video:
http://youtu.be/6MYW3LKZ4JE?hd=1
Mike's fastest run with in car video:
http://youtu.be/T1wSoiXGDrk?hd=1
Comparison of the two... this is what 0.053 seconds looks like:
http://youtu.be/MnwjjbLogo4?hd=1
Outside videos:
http://youtu.be/F-p9xTVNPOw?hd=1
http://youtu.be/WrOX4j1m3Rc?hd=1
http://youtu.be/5xoiJ14gzj8?hd=1
My fastest run with in car video:
http://youtu.be/6MYW3LKZ4JE?hd=1
Mike's fastest run with in car video:
http://youtu.be/T1wSoiXGDrk?hd=1
Comparison of the two... this is what 0.053 seconds looks like:
http://youtu.be/MnwjjbLogo4?hd=1
Outside videos:
http://youtu.be/F-p9xTVNPOw?hd=1
http://youtu.be/WrOX4j1m3Rc?hd=1
http://youtu.be/5xoiJ14gzj8?hd=1
Mar 28, 2012, 04:36 PM
#6
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Nice write up Aaron!
My impressions of the ACD tuning reflashing:
I like the fact we can tune the car for surface we are running on, low grip / wet, high grip. This will come in handy when were on concrete or when its wet out.
My speed in slalom increased, it seemed as though the car was more settled going through slalom gates with less drama from the rear end. This was determined at test and tune, slalomed with stock unit then we started using the reflashed ACD so we could see difference in car.
Our first event was a success, car was great, course was a sweeper intensive course with a few small slaloms sprinkled in. 1-2 PAX finish was quite the surprise, I hope were that lucky the rest of this year.
Looking forward to the DC Pro to really test it out.
My impressions of the ACD tuning reflashing:
I like the fact we can tune the car for surface we are running on, low grip / wet, high grip. This will come in handy when were on concrete or when its wet out.
My speed in slalom increased, it seemed as though the car was more settled going through slalom gates with less drama from the rear end. This was determined at test and tune, slalomed with stock unit then we started using the reflashed ACD so we could see difference in car.
Our first event was a success, car was great, course was a sweeper intensive course with a few small slaloms sprinkled in. 1-2 PAX finish was quite the surprise, I hope were that lucky the rest of this year.
Looking forward to the DC Pro to really test it out.
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Mar 28, 2012, 07:36 PM
#11
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that rear wing looks like the last wing element is way to steep to not be stalled out. have you done any CFD or tuft testing to see if its actually working with that much angle of attack?
we have used very very steep multi element wings in race cars but it takes 4 elements properly spaced to get the top element that much AOA.
we have used very very steep multi element wings in race cars but it takes 4 elements properly spaced to get the top element that much AOA.
Mar 29, 2012, 06:05 AM
#13
that rear wing looks like the last wing element is way to steep to not be stalled out. have you done any CFD or tuft testing to see if its actually working with that much angle of attack?
we have used very very steep multi element wings in race cars but it takes 4 elements properly spaced to get the top element that much AOA.
we have used very very steep multi element wings in race cars but it takes 4 elements properly spaced to get the top element that much AOA.
I will say it makes a notable difference in the feel of the car, so it is generating down force... Just need to work on optimizing the flow patterns to get the most out of it.
Last edited by psushoe; Mar 29, 2012 at 06:18 AM.
Mar 29, 2012, 01:05 PM
#15
Evolved Member
Awesome write up, definitely makes me keep an even closer eye on the ACD flash upgrade. How difficult is it to get the upgrade, do we need to send in our ACD?