Dyno Test Results - Stock airbox vs. ARC airbox
Jan 14, 2009, 05:43 PM
#1
Dyno Test Results - Stock airbox vs. ARC airbox
For years I've been using the stock airbox, stock rubber turbo inlet pipe, and stock BOV. They have performed very well and kept the car smooth and reliable, but I always wondered just what I was giving up in the way of power by sticking with the well-designed Mitsu parts.
I dropped the car off at Pure Tuning in Toledo, OH so Keith could perform the testing and tuning. He put the car on the dyno as delivered to get a baseline. This was the way the car was when we won 2 Solo2 National Championships this past September, and then subsequently ran an 11.000 @ 123mph at the dragstrip in October. Baseline was 357HP/372TQ on Pure Tuning's AWD Mustang Dyno. The following parts were on the car (only listing parts that have to do with power production):
stock intake box with Works drop-in filter
stock rubber turbo inlet pipe
FP EvoGreen turbo
Nisei LICP and UICP
ARC intercooler
stock Evo9 BOV
stock TB, intake manifold, head
Precision 880 cc injectors
stock ECU
GSC S1 cams
PPI ported stock exhaust manifold
Works O2 housing and 3" dowpipe
Aspec Products titanium test pipe
Greddy Ti catback
E85 fuel, 30psi spike falling to 23psi @ redline
Keith then installed the ARC airbox and set about to tune the car. The ARC box leaned the mixture out quite a bit. Upon trying to add fuel, we realized that the injectors were maxxed out. Calling up more duty cycle would not richen up the mixture. A set of 1200 cc injectors, fuel rail, and FPR were installed. This allowed the fuel tables to be tuned to for the ARC airbox. The result was 387HP/398TQ.
Then Keith swapped in an aluminum turbo inlet pipe to replace the corrugated rubber stock unit, with new numbers of 396HP/394TQ.
Keith had a hunch that the 30psi we were hitting in the mid-range was blowing open the stock BOV, so out it came and a Forge unit was installed in its place. With no other changes the car picked up 2-3psi of boost in the midrange, for a new total of 410HP/419TQ.
Now here is a before and after comparison of the baseline vs all the new parts installed and tuned:
Now for some notes and discussion on the testing and results:
- While we were playing with the ARC box, I decided I wanted to test the eBay knock-off of the ARC unit. The results were very interesting. The two boxes were dimentionally identical, but the ARC craftsmanship and welding was definitely better. Both boxes made EXACTLY the same amount of power when using the same air filter. The knock off comes with blue gauze K&N type filters while the ARC comes with red foam filters. The ARC filters outperformed the ones that came with the knock off box by about 5WHP though the entire powerband. One may think "well, I'll just get the eBay box and buy some ARC filters and be rockin" - BUT, the ARC filters cost about $200. When you add that with the cost of the eBay box you're right in the ball park of the real-deal ARC kit.
- I have had this entire test performed before at another shop, and the results there showed that adding an aftermarket airbox did not make any significant gains. Looking back on things I am sure the problem was fuel supply. We weren't able to tune in the newly added parts, so it seemed as though there was no power to be made. I've told many people that 880's were big enough for an E-85/FPGreen setup. I was wrong.
- Before the test the Green was maxxed out on the top end. Cranking the boost controller open did not yield any more power or psi above ~6K rpm. The intake tract changes allowed the turbo to pull in air more easily, therefore making more power. The BOV change allowed the boost that was being made to not be wasted, thereby making more power. The turbo is still maxxed out, it's just that the entire motor "system" was made more efficient, thereby making more power with the same amount of "work" from the turbo.
I would like to say a huge THANK YOU to Keith and the guys at PURE TUNING . They have been wonderful to deal with and everything they have done with my car has turned out superbly. They have a vast background in autocross and road racing, so their tuning ideals are a little different than some who deal mostly with drag racing.
EVOlutionary
I dropped the car off at Pure Tuning in Toledo, OH so Keith could perform the testing and tuning. He put the car on the dyno as delivered to get a baseline. This was the way the car was when we won 2 Solo2 National Championships this past September, and then subsequently ran an 11.000 @ 123mph at the dragstrip in October. Baseline was 357HP/372TQ on Pure Tuning's AWD Mustang Dyno. The following parts were on the car (only listing parts that have to do with power production):
stock intake box with Works drop-in filter
stock rubber turbo inlet pipe
FP EvoGreen turbo
Nisei LICP and UICP
ARC intercooler
stock Evo9 BOV
stock TB, intake manifold, head
Precision 880 cc injectors
stock ECU
GSC S1 cams
PPI ported stock exhaust manifold
Works O2 housing and 3" dowpipe
Aspec Products titanium test pipe
Greddy Ti catback
E85 fuel, 30psi spike falling to 23psi @ redline
Keith then installed the ARC airbox and set about to tune the car. The ARC box leaned the mixture out quite a bit. Upon trying to add fuel, we realized that the injectors were maxxed out. Calling up more duty cycle would not richen up the mixture. A set of 1200 cc injectors, fuel rail, and FPR were installed. This allowed the fuel tables to be tuned to for the ARC airbox. The result was 387HP/398TQ.
Then Keith swapped in an aluminum turbo inlet pipe to replace the corrugated rubber stock unit, with new numbers of 396HP/394TQ.
Keith had a hunch that the 30psi we were hitting in the mid-range was blowing open the stock BOV, so out it came and a Forge unit was installed in its place. With no other changes the car picked up 2-3psi of boost in the midrange, for a new total of 410HP/419TQ.
Now here is a before and after comparison of the baseline vs all the new parts installed and tuned:
Now for some notes and discussion on the testing and results:
- While we were playing with the ARC box, I decided I wanted to test the eBay knock-off of the ARC unit. The results were very interesting. The two boxes were dimentionally identical, but the ARC craftsmanship and welding was definitely better. Both boxes made EXACTLY the same amount of power when using the same air filter. The knock off comes with blue gauze K&N type filters while the ARC comes with red foam filters. The ARC filters outperformed the ones that came with the knock off box by about 5WHP though the entire powerband. One may think "well, I'll just get the eBay box and buy some ARC filters and be rockin" - BUT, the ARC filters cost about $200. When you add that with the cost of the eBay box you're right in the ball park of the real-deal ARC kit.
- I have had this entire test performed before at another shop, and the results there showed that adding an aftermarket airbox did not make any significant gains. Looking back on things I am sure the problem was fuel supply. We weren't able to tune in the newly added parts, so it seemed as though there was no power to be made. I've told many people that 880's were big enough for an E-85/FPGreen setup. I was wrong.
- Before the test the Green was maxxed out on the top end. Cranking the boost controller open did not yield any more power or psi above ~6K rpm. The intake tract changes allowed the turbo to pull in air more easily, therefore making more power. The BOV change allowed the boost that was being made to not be wasted, thereby making more power. The turbo is still maxxed out, it's just that the entire motor "system" was made more efficient, thereby making more power with the same amount of "work" from the turbo.
I would like to say a huge THANK YOU to Keith and the guys at PURE TUNING . They have been wonderful to deal with and everything they have done with my car has turned out superbly. They have a vast background in autocross and road racing, so their tuning ideals are a little different than some who deal mostly with drag racing.
EVOlutionary
Last edited by EVOlutionary; Jan 14, 2009 at 06:24 PM.
Jan 14, 2009, 06:26 PM
#3
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I've found the same thing. A good BOV always increased my boost by 2-3psi over a Mitsu BOV, I tested that many times.
I also noticed better boost response and better ability to hold boost when I ditched the stock intake tube and box.
Good info for sure. There is power to be made by upgrading those parts - but some people resist... "Give in to the power of the tea."
I also noticed better boost response and better ability to hold boost when I ditched the stock intake tube and box.
Good info for sure. There is power to be made by upgrading those parts - but some people resist... "Give in to the power of the tea."
Jan 14, 2009, 08:46 PM
#5
Just to play a bit of the devil's advocate, I do wonder if you had larger injectors and the "upgraded" BOV what numbers you would have gotten that same day. You seem to somewhat acknowledge that in your summary, of course.
50's a bit tall to ask, sure, but with all the right supporting mods it helps...
Thanks for posting. We need more of such testing.
How's the idle?
50's a bit tall to ask, sure, but with all the right supporting mods it helps...
Thanks for posting. We need more of such testing.
How's the idle?
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Jan 15, 2009, 06:22 AM
#8
Yes, the car originally had the EVO 9 (AKA JDM MR) BOV - the metal one. It works awesome - super smooth, never any fluttering or surging issues. If I can't get the aftermarket BOV to be 100% perfect with regards to driveability, I will take the power loss and switch back to the stock one. . .
Not really following you here. All runs, inclucing baseline were done in a couple days. Weather was not a factor, as it was freakin cold all the time and there is no humidity in the air to speak of. For the baseline runs the car was properly tuned for A/F ratio, so there was no need for larger injectors at that time. Adding larger injectors and then cutting back duty cycle to spray the same amount of fuel as before should not net any gains or losses in power.
Adding the BOV first rather than last I would suspect would yield approximately the same gains either way - as long as you are pushing the boost past the leak threshold of the BOV. (*this may be different for different BOV's. One that is brand new may hold 30psi fine, whereas one that is 3 years old with lots of miles may leak sooner)
It is a custom s-shaped 3" unit built by Pure Tuning. Similar to the RMR or PPI unit, but a bit longer to work well with the ARC box.
EVOlutionary
Adding the BOV first rather than last I would suspect would yield approximately the same gains either way - as long as you are pushing the boost past the leak threshold of the BOV. (*this may be different for different BOV's. One that is brand new may hold 30psi fine, whereas one that is 3 years old with lots of miles may leak sooner)
EVOlutionary
Last edited by EVOlutionary; Jan 15, 2009 at 06:35 AM.
Jan 15, 2009, 06:55 AM
#9
Sorry, but the implication here is that your injectors were maxed out, pretty much, before the test, while still on the stock intake. If they were, or at least registering close, isn't it possible larger injectors at lighter duty would have richened up the stock airbox build a bit, and, allowed the new BOV's extra PSI to be utilized to boot?
And the addition of the hard pipe would seem to be close to within the margin of error in numbers considering you're pushing 400awhp?
Again, not trying to be critical, it's just what comes to (a perhaps dubious) mind when reading your accounting.
Thanks.
*Edit*
Oh! And how's the idle?
Again, thanks.
And the addition of the hard pipe would seem to be close to within the margin of error in numbers considering you're pushing 400awhp?
Again, not trying to be critical, it's just what comes to (a perhaps dubious) mind when reading your accounting.
Thanks.
*Edit*
Oh! And how's the idle?
Again, thanks.
Jan 15, 2009, 08:24 AM
#11
Kazz,
Yes, if one were to have installed the new BOV first it is possible that the higher boost level would cause a lean condition if the injectors could not flow enough. Then swapping the injectors would be necessary to see the gains from adding the BOV.
I see your point about the baseline vs. the airbox test not being a true back to back apples to apples comparison because of the added fuel system mods. Personally, I feel that had we done the fuel system upgrades first then re-baselined it, there would be minimal if any change in HP, as the target AFR and timing maps and boost level would not be changed. . .
As far as idle, I have not had a chance to really drive it or pay attention to the idle. Then only time the car's been fired up was to roll it off the trailer and into the dealership to get cleaned up. Here's what you get towing an open trailer 3 hours through a blizzard. It was so cold that the salt/snow/slush mixture was frozen solid:
Yes, if one were to have installed the new BOV first it is possible that the higher boost level would cause a lean condition if the injectors could not flow enough. Then swapping the injectors would be necessary to see the gains from adding the BOV.
I see your point about the baseline vs. the airbox test not being a true back to back apples to apples comparison because of the added fuel system mods. Personally, I feel that had we done the fuel system upgrades first then re-baselined it, there would be minimal if any change in HP, as the target AFR and timing maps and boost level would not be changed. . .
As far as idle, I have not had a chance to really drive it or pay attention to the idle. Then only time the car's been fired up was to roll it off the trailer and into the dealership to get cleaned up. Here's what you get towing an open trailer 3 hours through a blizzard. It was so cold that the salt/snow/slush mixture was frozen solid:
Jan 16, 2009, 07:29 AM
#13
I thought there should be some gains, but to tell you the truth, I had no idea there was this much to be made! 
Even though the car didn't have a ton of mods and the motor and head were 100% stock except some small cams, the car has always made awesome power. I thought it was near being maxxed out. With this same baseline setup (stock airbox, stock bov) that made 357hp/372tq on this particular Mustang dyno the car ran an 11.000 @ 123mph. Also with that same list of parts the car made 440whp and 454tq on a Dynojet. I hate playing the dyno guessing game, but if the gains are to be believed, that should put it in the 470whp-500whp range on a Dynojet! I hope to get the car on a Dynojet this summer to comfirm. . .
Not too shabby for an FP Green on stock motor, stock head, stock intake manifold, stock throttle body, stock MAF, stock ECU . . . . This turbo absolutely kicks butt. I've said it before and I'll say it again - THANKS to Robert and the team at Forced Performance for the innovation that keeps our sport so fun!
Also thanks to Keith at Pure Tuning for helping my EVO continue it's path of evolution. . .
EVOlutionary
Even though the car didn't have a ton of mods and the motor and head were 100% stock except some small cams, the car has always made awesome power. I thought it was near being maxxed out. With this same baseline setup (stock airbox, stock bov) that made 357hp/372tq on this particular Mustang dyno the car ran an 11.000 @ 123mph. Also with that same list of parts the car made 440whp and 454tq on a Dynojet. I hate playing the dyno guessing game, but if the gains are to be believed, that should put it in the 470whp-500whp range on a Dynojet! I hope to get the car on a Dynojet this summer to comfirm. . .
Not too shabby for an FP Green on stock motor, stock head, stock intake manifold, stock throttle body, stock MAF, stock ECU . . . . This turbo absolutely kicks butt. I've said it before and I'll say it again - THANKS to Robert and the team at Forced Performance for the innovation that keeps our sport so fun!
Also thanks to Keith at Pure Tuning for helping my EVO continue it's path of evolution. . .
EVOlutionary
Jan 16, 2009, 09:17 AM
#14
Good Info and looks to be a pretty good test, I dont believe the injectors would have made much of a difference anyhow as long as your fueling was adequate previously. With the stock intake you didnt need additional fuel because you werent flowing enough air to require it. I think in most cases there is performance to be had from a well designed intake.
What were the ambient temps when you did the testing and was the hood closed when you performed your testing on the dyno?
What were the ambient temps when you did the testing and was the hood closed when you performed your testing on the dyno?
Last edited by Mr. Evo IX; Jan 16, 2009 at 09:21 AM.