Aerochargers TT more testing

Well I finally had time to get back on the dyno and play with my tune and the vain controllers on the Aerocharger variable vain turbos. My car is an '04 running FIC w/550cc injectors and twin T66 Aerocharger turbos.

For those that do not know the Aerocharger is a variable vain turbo and the early versions were used for the first time on an NSX by Bell Engineering. There are lots of threads in the Prime Forums going over the old Bell Design. I designed and built a twin turbo setup of my own loosely based on the old Bell kit but with the new large frame T66 Aerocharger turbos and my own WTA intercooler design. Someday I will have time to document it in a build thread but I really do not have time now but wanted to share the results of my testing as I know of a few guys that are considering the Aerochargers in their builds.

About 18 months ago I first tuned my system and while I was not 100% sure what the system could do I was very happy with the results of the first dyno sessions. I did plan on re-tuning the system after some road time and miles. I also wanted to be more aggressive as my original tune was extreemly conservative with AFR's during WOT set at 11.0 and pulling 1* of timing for every pound of boost added.

The first Dyno shows the difference between 8lbs of boost and the effect of changing the vain controller. The Vain controller effects how quickly the turbo spools. This run shows the controller at the slowest spool compared to the middle spooling rate. I can make them spool even quicker but that will be for another dyno session, right now I like the middle setting on the street and it is nice knowing I can go further if I need to. The other changes made to the tune were to raise AFR's from 11.0 to 11.6 and add 1* more timing at peak boost.



The next dyno shows shows a comparison of 8lbs and the medium setting for the vain controller and 6lbs using the same medium setting on the vain controller and the baseline pull prior to the TT install.



Finally I have a track day coming soon so this is my track tune compared to the baseline pull.



I plan to run 400whp on the track and the 440whp on the street, as a side note and some 35 pulls today the IAT's were rock solid at 109* with a single dyno fan blowing accros the heat exchanger and the engine radiator. We will see what happens at the track but I am happy with the results so far.

Dave

fwiw my SOS twin setup has seen a max intake temp of 110 with about 12 20 minute sessions on the track. not sure why it stops there... it shoots up quickly, from say 70F, but just sits there no matter how hard I run the car on the track. this is 8 psi/515 rwhp.

peiserg said:

fwiw my SOS twin setup has seen a max intake temp of 110 with about 12 20 minute sessions on the track. not sure why it stops there... it shoots up quickly, from say 70F, but just sits there no matter how hard I run the car on the track. this is 8 psi/515 rwhp.

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3.0 or 3.2? Stock internals or no?

HIJACKER said:

3.0 or 3.2? Stock internals or no?

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3.2 w/built motor.

Im confused as to why you both are running 8psi but have 100 hp difference? Is it timing and fuel?

Ko-nsx said:

Im confused as to why you both are running 8psi but have 100 hp difference? Is it timing and fuel?

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My guess, because I'm not a FI expert, is psi is a measure of pressure but cfm is a measure of volume. Dave's car flows more volume of air at the same 8 psi. Both are 2x turbos. That's why a single turbo system or SC at 8psi nets around 370-380 rwhp. Curious to hear the answer.

Ko-nsx said:

Im confused as to why you both are running 8psi but have 100 hp difference? Is it timing and fuel?

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Not quite 100whp difference he is at 515 and I am at 442 so 73whp.

Also based on this post I think Peiserg is at 9.2lbs and 515whp so the boost levels vs whp may actually be a little closer.
http://www.nsxprime.com/forum/showpost.php?p=1466205&postcount=23

I am still a bone stock 3.2l un-opened motor. I think there is more to be had than 440whp but at what risk. I have pushed my stock bottom end as far as I am willing to go. If I make the move to meth and a full stand-a-lone ECU then I will push it a little more and she will probably end up at the 465-475 mark with meth and more timing. It just is not worth the risk for me. I really never intended the car to make over 400whp, and based on my experience with my previous CTSC I thought it was going to take 9 to 10lbs to get there. I am there on 6.2lbs average and 6.4lbs peak.

On the street I will run 8.4lbs and at the track I will run 6.2lbs, I am still planning to blend to 96 octane by adding some Sunoco 104 with the pump gas to get an extra margin of safety on the track, but I really like were the car is at and feel like I am just going to enjoy the car now.

For those who have considered building your own setup I have found it to be a very rewarding project, and the Aerochargers were everything I hoped they would be and then some. As always anyone looking to make a move on their own TT setup feel free to ask any questions you may have I see no reason not to share the data I have collected with this project.

peiserg said:

fwiw my SOS twin setup has seen a max intake temp of 110 with about 12 20 minute sessions on the track. not sure why it stops there... it shoots up quickly, from say 70F, but just sits there no matter how hard I run the car on the track. this is 8 psi/515 rwhp.

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That is good news as you and I are running the same heat exchanger and pump so I hope my results are the same as yours.

Dave

yes you are correct dave i meant 9.2 psi. thats the minimum i can run with my setup due to the wastegate i beleive.

I actually did ask SOS to turn it down even more, say to 7 psi so it wouldn't be too hard on the motor at the track, but it turned out to be more involved than say just plugging in the computer and typing in a command.

As it is, i run 9.2 psi 95% of the time, and 15.8 psi when the occasional pesky R6 or GSXR 750 needs to learn that not all NSX's are slow.

I have the 53 series Aerodynes and have been advised not to exceed 6# of boost. Are the 66 series able to run more pressure? What kind of controllers do you have that you can adjust when they kick in? Very nice numbers by the way.

Valhalla said:

I have the 53 series Aerodynes and have been advised not to exceed 6# of boost. Are the 66 series able to run more pressure? What kind of controllers do you have that you can adjust when they kick in? Very nice numbers by the way.

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The 53 and the 66 are very different turbos, the T53 is what Aerocharger calls a small frame turbo and the T66 is the large frame. The T66 is much larger in size and have a much higher CFM and pressure rating. They do however have the same basic concept of a self contained oiling system and vain controller. The largest 53 series is good for 340 CFM max and the largest 66 series is good for 540 CFM max. I am running two 66 series 178/430 trim rated at 430 CFM max each. At the 400whp power level I am aprox 340 CFM at each turbo. The 440whp the aprox airflow needed is 360 CFM each. The T53 is just two small and forces the turbine to over-spool and exceed its safe RPM, and then they fail. When Corky designed the original BEGI system the goal was around 350whp/390bhp that meant you needed aprox. 290 CFM and that was the sweat spot for the T53 series 128/305.

This is a video that shows the basic concept of the vain controller.
http://www.youtube.com/watch?v=glskvHdukiQ

Your T53 series turbo have a similar controller as the new units and the older units can be upgraded to the new controller type, they all work the same way just some are easier to adjust and have proven to be more reliable than others.

This may be more than you wanted to know but, the vain controller controls the peak boost the system will see and the rate it will be achieved. Setting the controller to direct the exhaust gasses at the outer tips of the turbine wheel and the turbo will spool quicker, set it to hit the middle of the turbine and the the turbo will spool slower than if the exhaust was on the tip, direct it at the center of the turbine wheel and there is less leverage on the wheel and the turbine slows. If you keep directing the exhaust gasses at the turbine tip only the turbo will continue to accelerated and exceed its maximum RPM and then fail. To keep the turbo from over spooling they needed a limiting device, sort of like a waste-gate acts in a traditional turbo, but instead of reducing exhaust flow by bypassing exhaust through the waste-gate they simple turn the vain and force the exhaust to flow closer to the center of the turbine wheel and away from the tips. So as pressure/boost is built at the turbos outlet nozzle the vain controller uses this boost as a reference to overcome the spring in the controller and force the vain to direct the exhaust gasses at the center of the turbine wheel and away from the tip. This causes the turbine to stabilize its RPM's and peak boost is maintained. Increase the spring rate in the controller and more force/higher boost reference is needed to overcome the spring and stabilize the turbine RPM. The net result is the higher the spring rate in the controller the higher the boost levels and turbine RPM's you will get. Stay within the limits of the turbo and all is good.

The vain controller also allows you to pick the at rest point the vains are sitting at, the at rest point is where the vains go to when not enough exhaust energy is present to create boost. This is the setting that is used to adjust the ramp rate of the spooling. If you set the vains to rest at the middle of the turbine wheel less leverage is acting on the turbine and the result is a slower spool to peak boost. Set the rest point to catch just the tip of the turbine wheel and the most leverage possible from the incoming gasses causes the turbine to spool as fast as possible until it reaches a boost level at the turbine nozzle that is strong enough to overcome the spring in the vain controller, the vains start to direct exhaust away from the tip of the turbine and towards the middle of the turbine wheel, the turbine starts to slow and the peak boost pressure is maintained. It is a simple and elegant solution to controlling the turbine. The benefit is what amounts to a controllable spool rate and that all exhaust gasses pass over the turbine wheel and are not required to change paths in the exhaust system like when a traditional waste-gate is used to limit boost. Also in theory no waste-gate or blow-off valve is needed to control the turbo. Most system will still use a blow-off to keep the turbine moving when the throttle is rapidly closed but it is not required.

Dave

Ko-nsx said:

Im confused as to why you both are running 8psi but have 100 hp difference? Is it timing and fuel?

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Different sized turbo's produce different amounts of cfm. A small turbo may produce 350whp at 10psi, and a larger turbo can produce 500whp at 10psi. Think of it as a refresh rate, the larger turbo can/does fill the cyl volume quicker than the smaller turbo will.

Thank you Dave for taking the time to explain these.

I am a little surprised though at the difference between the slow and middle spool dyno results with the vane controller. I thought there would have been a larger difference between them.

Now, it looks like you have the newest single port controller. If so, that should be infinitely adjustable version between open and closed with the set screw and jam nut. Was the "middle" spool rate just measuring the turns on each screw? If so, that might explain it, but I would REALLY love to see a dyno plot of these babies set on quickest spool please :smile: I admit, I want full boost at 3k RPMs.

One of my concerns would be ensuring each turbo is set up to control the vanes the same way to minimize back pressure variance between the banks as well as the two cpmpressors fighting each other. I wonder if that is what their "multiport vane controller ensures?" Can I use one controller for both turbos?

Thanks for the writeup!

Dave

Mac Attack said:

I am a little surprised though at the difference between the slow and middle spool dyno results with the vane controller. I thought there would have been a larger difference between them.

Now, it looks like you have the newest single port controller. If so, that should be infinitely adjustable version between open and closed with the set screw and jam nut. Was the "middle" spool rate just measuring the turns on each screw? If so, that might explain it, but I would REALLY love to see a dyno plot of these babies set on quickest spool please :smile: I admit, I want full boost at 3k RPMs.

One of my concerns would be ensuring each turbo is set up to control the vanes the same way to minimize back pressure variance between the banks as well as the two cpmpressors fighting each other. I wonder if that is what their "multiport vane controller ensures?" Can I use one controller for both turbos?

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The difference in what I am calling the slow setting and the middle setting is one complete turn on the controller. The slow spool is set at two turns in, the middle setting is at 1 turn in, you can set it at zero turns in and that would be the quickest spooling possible. I would be concerned about a possible choke point if the vains are closed down that much on the zero setting. Both turbos need to have the vain controllers set at the exact same settings and the boost refference for each turbos need to be tied together so they act and re-act to the changes in peak boost together. You could turn the controller in past the two turns but the spool would be very slow and would negate any benifit of this type of turbo.

I have not played with anything below the 1 turn in setting yet, but the way the spool rate changed I can see you getting to full boost by 3500-4000 RPM and maybe sooner. Keep in mind that a NSX spends very little time below 3k RPM even in you normal around town driving and there is something to be said for a smoother spool to peak boost. These turbos are making boost almost instantly on WOT, starting at 2.2k RPM in fourth gear on the dyno and
by 2.5k RPM you are making 1lb, by 2.8k RPM you are making 2lbs, by 3.3k RPM its 3lbs, by 3.6k RPM it is 4lbs, by 3.9k RPM it is 5lbs.

With my setting change going from two turns in to one turn in the torque numbers changed quite a bit in the 3k to 5k rpm range. This may help to see the numbers. The following are TQ numbers at the different vain settings for a given RPM.

RPM V-1 V-2 Net TQ
3.0k 229 218 +11
3.5k 251 235 +16
4.0k 277 246 +31
4.5k 313 268 +45
5.0k 324 303 +21

One addtional turn out from my starting location moved the torque curve down 1k RPM's at the bottom end and they were vertually equal by 5300 rpm. One thing I was happy to see was the peak boost is now happening before VTEC instead of right at VTEC. and the tune is easier to work with this being the case. I will play with the vain controller more in the weeks to come and I am considering a boost controller so I do not have to change springs in the vain controller to switch between the street/track mode, but a spring change takes less than 5 min per turbo on the ground and less than 3 min if the car is on a rack. I will most likely keep it simple and just change the springs as needed.

Dave

Man I miss those Aerochargers... Rock on!

I was/am curious how you make sure the turbos are pushing out the same amount of charge air as they are independent of each other. By adjusting the set screw, you should be close but how do you know how close? Do you connect the boost hoses from the controllers together with a T fitting? And do these regulate boost from each charge pipe, or do you connect to the intake manifold after the throttle body with one hose?

Great write up and can't wait to see you build thread.

Valhalla said:

I was/am curious how you make sure the turbos are pushing out the same amount of charge air as they are independent of each other. By adjusting the set screw, you should be close but how do you know how close? Do you connect the boost hoses from the controllers together with a T fitting? And do these regulate boost from each charge pipe, or do you connect to the intake manifold after the throttle body with one hose?

Great write up and can't wait to see you build thread.

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The two boost refference fittings at the turbo outlet nozzels are tied together. This makes the boost reference at the two controllers be an average of the two turbo outlets and the vain controllers move as one.

I removed the caps from both vain controllers and used a dial indicator to make sure that the two turn in setting was the same on both caps, then I marked the outside of each cap and the center set screw so I could then count turns and always have a refference point to make sure my turns were the same. There is a more accurate way of getting the controllers to be set exactly the same, I saw the setup when I was at Aerochargers offices in KC. They used 4 very sensitive pressure transducers and 4 gauges to measure both turbos inlet exhaust pressure and outlet boost pressure. They adjusted everything untill they matched. It was very time consuming and very expensive to setup as the exhaust pressure measurment required very long copper tubing to prevent heat damage to the sensor. In the end the method I used is the recommended method by Aerocharger.

Dave

Dave, how's it running these days?

Have you installed your clutch yet?

Any feedback from your latest track day?

How are you de-tuning for the track? pulling back more Timing and boost?

EAC said:

Dave, how's it running these days?

Have you installed your clutch yet?

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Just got back from Putnam Park late last night, we did two days Sat we got the most rain I have ever seen at a track day, so not to much time to play on the track. Sunday was sunny and 75, perfect. Ran 6 20min session on the 400whp tune and the turbos were perfect, not one issue. IAT never over 120 and the car was a blast. The exhaust got real hot as by day end I now have blue and gold colored chrome tips at my exhaust.

At Putnam I found myself running out of gear in places I never would have before. and since I still had the stock clutch in place I could not go up to 5th on the straight as the clutch would not hold in 5th at WOT. So once I hit 120mph I had to coast untill braking for turn 1. I ran out of gear from turns 3-4 and 8-9 as well. I tried running the back side of the track in 4th to avoid running out of gear but it was not as fast out of the corner and with the rest of the hardware in my run group I needed everything to have a chance. I was tempted to change the springs and run the 440whp tune but with my stock clutch it just made no since.

I went up with two well prepped Z06 built at our shop and lets just say the 610whp TVS Blower Z06 was impossible for almost anyone to play with on the straight, the big HP Vipers could hang but not pass. The other Z06 was a Carbon Edition with long tubes, cold air and tune making 500whp N/A, I could hang on his bumper untill 120mph then he pulled away as I was not able to go to 5th. Everywhere else on the track he was faster and I had to give him the point by. It was close and with the new clutch and another 40whp I could have made it much harder for him to get around, but between the 100whp difference and the 13" wide cup tires I had a lot to make up for with driving skills and I just did not have enough to get it done.

Looks like I will be doing the clutch for sure before the next event.

Dave

Any updates? Did you get the new clutch and have you been back to the track?

I am curious to see pictures of your setup. I think I am going the same route.

Nick675 said:

Any updates? Did you get the new clutch and have you been back to the track?

I am curious to see pictures of your setup. I think I am going the same route.

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Clutch finally goes in this weekend, as I am headed to Autobahn Road Course the following weekend. I may run this track event on the 440 tune, looking at the rest of my run group I should not have to many problems even if I stay at the 400 tune. Autobahn is not really a technical track but it has a lot of turns and not a lot of long straits. I will log some more data and add info to this post when I get back. I will also have some feedback about the Sport 6-puck after the weekend as well.

If you decide to build your own or jest go with the Aerochargers let me know, I have a few ideas that should make life easier for you.

Dave

DDozier said:

Clutch finally goes in this weekend, as I am headed to Autobahn Road Course the following weekend. I may run this track event on the 440 tune, looking at the rest of my run group I should not have to many problems even if I stay at the 400 tune. Autobahn is not really a technical track but it has a lot of turns and not a lot of long straits. I will log some more data and add info to this post when I get back. I will also have some feedback about the Sport 6-puck after the weekend as well.

If you decide to build your own or jest go with the Aerochargers let me know, I have a few ideas that should make life easier for you.

Dave

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Good luck Dave. If you need any help, text me.

DDozier said:

Clutch finally goes in this weekend, as I am headed to Autobahn Road Course the following weekend. I may run this track event on the 440 tune, looking at the rest of my run group I should not have to many problems even if I stay at the 400 tune. Autobahn is not really a technical track but it has a lot of turns and not a lot of long straits. I will log some more data and add info to this post when I get back. I will also have some feedback about the Sport 6-puck after the weekend as well.

If you decide to build your own or jest go with the Aerochargers let me know, I have a few ideas that should make life easier for you.

Dave

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Good luck!

Does the 6-puck require a break-in period?

RYU said:

Good luck!

Does the 6-puck require a break-in period?

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yep, but I have a full week to get some miles on and heat cycles on the clutch before my track day. Should not be an issue.

Dave

Dave you are one of my favorite members here. All your posts are informative and well written and your work is meticulous, you add a lot of value to this community... Much appreciated.