Air box mod save $$$
- Thread starter CIP57_imp
- Start date
The Spaceman_imp
Road warrior
LMAO what the hell are those shoe hornsCIP57_imp said:
Oops, I meant to post a link to the TSR Air Funnel! I think that error created confusion about cip57's obviously ingenious mod, and perhaps some of the ensuing rhubarb.
"My bad," as the youngsters say.
For those considering modifying their air intake:
I did dynometer runs comparing various intake and exhaust configurations.
1) Stock everything
2) Unrestricted exhaust (Yoshimura full) with TSR air intake
3) Unrestricted exhaust with stock air intake (stock air filter)
While the air-fuel ratios changed, the HP curves for each of these configurations was exactly the same.
I am unwilling to compromise intake air filtration, but before you conclude that the stock air filter is holding the performance back, another member ran butt dynos comparing unrestricted air intake (no snorkel or air filter) to stock and could not detect a difference.
I did dynometer runs comparing various intake and exhaust configurations.
1) Stock everything
2) Unrestricted exhaust (Yoshimura full) with TSR air intake
3) Unrestricted exhaust with stock air intake (stock air filter)
While the air-fuel ratios changed, the HP curves for each of these configurations was exactly the same.
I am unwilling to compromise intake air filtration, but before you conclude that the stock air filter is holding the performance back, another member ran butt dynos comparing unrestricted air intake (no snorkel or air filter) to stock and could not detect a difference.
Ridem32_imp
Road warrior
DAC: I say this with tears running down my face! Will miss you ! I hope the kick in the ole bootie don't hurt to bad as you fly out the forum door !! Lol lol. 
Ha, DAC.
I got spanked for my part in this kerfuffle but it occurred to me that even though this is an old thread, new members are coming in and reading what is old stuff for us.
I did the controlled testing after this dust-up and think my results are repeatable. After all we're talking real time and dollars and people should be informed.
If the mods are being done for aesthetic reasons or simply because it's there, then that's fine, but facts is facts.
(Don't taze me dude!)
I got spanked for my part in this kerfuffle but it occurred to me that even though this is an old thread, new members are coming in and reading what is old stuff for us.
I did the controlled testing after this dust-up and think my results are repeatable. After all we're talking real time and dollars and people should be informed.
If the mods are being done for aesthetic reasons or simply because it's there, then that's fine, but facts is facts.
(Don't taze me dude!)
Air box mods are very popular with the Bonneville crowd. Often referred to desnorkling the air box, this mod, combined with a less restrictive exhaust supposedly lets the engine breathe easier and produce more power.Greg_imp said:
Greg did dyno testing of various intake and exhaust configurations. I find the results interesting and worthy of follow-up. But the results seem to contradict the claims of aftermarket manufacturers and the experience of other riders.
I haven't done any dyno testing and can only go by seat-of-the-pants "testing". My first mod was a Staintune. I did not notice any increase in power. When I opened the intake with a TSR air funnel, the bike seemed a lot more lively.
Several other members have done intake and exhaust mods and seen significant HP gains, verified by dyno testing.
Greg, I’m not disputing your results, but I remain unconvinced that opened up air boxes and CAT free exhausts will only affect A/F ratios while HP numbers remain unchanged.
Now I've done it
rboe
Road warrior
You should see a good ten percent gain, but that is only if you use pre-filtered spring air sold under the Honda brand. Don t try it with recycled air, oxygen molecules can only be reused just so many times before they get tired and simply don't perform as expected.
:angel:
:angel:
Ridem32_imp
Road warrior
All I can say is this ! I got a friend with a gsxr1000 he put a new exhaust on it sounded great! But his drag strip times dropped. Put his stock pipe back on and his drag strip times went back up! Dyno don't lie. Lots of guys buy pipes, K&N filters thinking more power more speed when most bikes lose performance FACT
In spite of my own numbers, something changed when I modified the exhaust. Throttle response seemed more lively, as I've said elsewhere, I felt less vibration, and of course it sounded much better. The aesthetic experience of riding was enhanced.
Since my ECU / ECM is stock, my bike is limited in rear wheel speed and rpms. My rough calculation is that at 7,500 rpm my motor is sucking in about 140 cubic feet of air per minute, which is in the range of a medium sized shop vac. Obviously, the intake plumbing creates some resistance which results in some reduction of air mass in the air box. Air mass sensing is the biggest factor in EFI, since it has to accommodate quite a large range of atmospheric pressures. Ferret was recently at 14,000 feet and it would be interesting to hear if he noticed any difference in performance given since at that altitude atmospheric pressure is about 15% of what it is at sea level.
My point is that adjusting for air mass is the main thing the ECM does, so small changes in intake resistance are not going to make any difference in performance, at least below 7,500 rpms. However, if the rpm limiters are removed, a much higher air flow is possible and then intake air resistance might be a factor.
I don't know how to explain the feeling of increased liveliness without a measured change in the hp curve, but again, in my experience, this resulted from exhaust changes, not air intake.
I believe CIP57 reported faster speed trials with the stock air intake than with "opened up" intake. I've read in other places that there's some serious mojo put into air box design, what with resonance and all that but that is all way above me.
edit: with ECM limiters in place, peak dyno hp results vary depending on what gear is used. In 5th gear, rear wheel speed limits hp below 80, in 4th gear you might see 80. I got 85 by running in 3rd gear and it appears that rpm limiters are what sets the peak reading. YMMV.
edit: edit: In 1st, 2nd, 3rd rpm limits dyno peak hp. In 4th and 5th the stock rear wheel speed limit caps the peak hp.
Since my ECU / ECM is stock, my bike is limited in rear wheel speed and rpms. My rough calculation is that at 7,500 rpm my motor is sucking in about 140 cubic feet of air per minute, which is in the range of a medium sized shop vac. Obviously, the intake plumbing creates some resistance which results in some reduction of air mass in the air box. Air mass sensing is the biggest factor in EFI, since it has to accommodate quite a large range of atmospheric pressures. Ferret was recently at 14,000 feet and it would be interesting to hear if he noticed any difference in performance given since at that altitude atmospheric pressure is about 15% of what it is at sea level.
My point is that adjusting for air mass is the main thing the ECM does, so small changes in intake resistance are not going to make any difference in performance, at least below 7,500 rpms. However, if the rpm limiters are removed, a much higher air flow is possible and then intake air resistance might be a factor.
I don't know how to explain the feeling of increased liveliness without a measured change in the hp curve, but again, in my experience, this resulted from exhaust changes, not air intake.
I believe CIP57 reported faster speed trials with the stock air intake than with "opened up" intake. I've read in other places that there's some serious mojo put into air box design, what with resonance and all that but that is all way above me.
edit: with ECM limiters in place, peak dyno hp results vary depending on what gear is used. In 5th gear, rear wheel speed limits hp below 80, in 4th gear you might see 80. I got 85 by running in 3rd gear and it appears that rpm limiters are what sets the peak reading. YMMV.
edit: edit: In 1st, 2nd, 3rd rpm limits dyno peak hp. In 4th and 5th the stock rear wheel speed limit caps the peak hp.
I could definitely see that happening. The stock ECU is set up for the stock airbox and exhaust. Altering those componets without an ECU reflash, tuned Power Commander etc. can mess things up.Ridem32_imp said:
Now you'll probably blow my mind by saying that GSXR had a properly tuned air/fuel controller and still lost power.
rboe
Road warrior
If the bike sounds louder or different the rider will tend to think there is a performance gain. Some of this is probably an unconscious desire to justify the work done or money spent, on the mod. Just human nature so something to be mindful of (and dyno does not care one way or the other)
No way to really tell until you dyno it. Nothing like cold hard facts.
No way to really tell until you dyno it. Nothing like cold hard facts.
Let me add to this:
I ran the following 0-100 times
Stock 9.1
Flashed 9.0
Yoshi Open Airbox 8.3
Yoshi Closed airbox 8.0
As i mentioned, these runs where all in the same place. The two Yoshi runs where on the same day and conditions.
Edit: I have documented these gains with video's.
I ran the following 0-100 times
Stock 9.1
Flashed 9.0
Yoshi Open Airbox 8.3
Yoshi Closed airbox 8.0
As i mentioned, these runs where all in the same place. The two Yoshi runs where on the same day and conditions.
Edit: I have documented these gains with video's.
Yes, it would be good to have some confirmation of these results which were done without a piggyback fuel controller.CB4ME_imp said:Air box mods are very popular with the Bonneville crowd. Often referred to desnorkling the air box, this mod, combined with a less restrictive exhaust supposedly lets the engine breathe easier and produce more power.Greg_imp said:
Greg did dyno testing of various intake and exhaust configurations. I find the results interesting and worthy of follow-up. But the results seem to contradict the claims of aftermarket manufacturers and the experience of other riders.
I haven't done any dyno testing and can only go by seat-of-the-pants "testing". My first mod was a Staintune. I did not notice any increase in power. When I opened the intake with a TSR air funnel, the bike seemed a lot more lively.
Several other members have done intake and exhaust mods and seen significant HP gains, verified by dyno testing.
Greg, I’m not disputing your results, but I remain unconvinced that opened up air boxes and CAT free exhausts will only affect A/F ratios while HP numbers remain unchanged.
Now I've done it
flynrider
Road warrior
That is so true. I used to operate the dyno at my friend's bike shop on the weekends (back in the 80s). There were a lot of folks that were certain they'd bumped up the hp by just slapping a pipe on their UJM and making no other changes . While their bikes were certainly much louder, invariably the dyno showed they had less power than before. Even after the proper tuning of intake and exhaust mods were done, the extra power usually showed up at rpms that the rider rarely saw on the street.Rboe_imp said:
The shop had a race bike that we constantly tuned and retuned using both the dyno and a set of test pipes equipped with fast response EGT probes (fancy stuff back then!). Even with all that equipment it was often difficult to get the right combination of mods tweaked just right to produce more power.
Things are a bit easier these days with an ECM in charge, but even so, performance tuning is still a bit more art than science.
Dengie Boy_imp
First service completed
I was doing some calculations on this very subject last night on my work bench! Having lost the plot on the PAIR valve mod subject (look up the thread) I decided this time to do my own research.
I measure the cross sectional area of the aperture in the end of the snorkel to be 31cm2, the diameter of the hole into the centre of the air filter element to be 20.5cm2 and the area of each throttle body venturi to be 10.05cm2.
7,500rpm is 125revs/sec and in the case of a 4 stroke 4 that equates to 250 intake strokes per second, which act like vacuum pulses in that massive sandwich box of an air cleaner. These individual pulses from each of the venturis in turn will probably appear as one by the time they get through the filter element, leaving the snorkel to act as a velocity stack? Just a thought.
Snorkels are usually fitted to internal combustion engines to silence intake roar. Just another thought.
Any way here it is:
And here it is with the strange rubber bung removed (32mm in diameter), increasing the intake area from 31.5cm2 to 41.5cm2:
I reckon this will just mess up some of the velocity stack effect. Dyno?
Shame you can't just turn the snorkel around to face the breeze!
Cheers
Dengie
I measure the cross sectional area of the aperture in the end of the snorkel to be 31cm2, the diameter of the hole into the centre of the air filter element to be 20.5cm2 and the area of each throttle body venturi to be 10.05cm2.
7,500rpm is 125revs/sec and in the case of a 4 stroke 4 that equates to 250 intake strokes per second, which act like vacuum pulses in that massive sandwich box of an air cleaner. These individual pulses from each of the venturis in turn will probably appear as one by the time they get through the filter element, leaving the snorkel to act as a velocity stack? Just a thought.
Snorkels are usually fitted to internal combustion engines to silence intake roar. Just another thought.
Any way here it is:
And here it is with the strange rubber bung removed (32mm in diameter), increasing the intake area from 31.5cm2 to 41.5cm2:
I reckon this will just mess up some of the velocity stack effect. Dyno?
Shame you can't just turn the snorkel around to face the breeze!
Cheers
Dengie
I didn't notice any difference in sound without the snorkel; and it's called that because it's designed to prevent the engine inhaling water. The rubber bung covers the place where an emission device not required in the USA is connected.
When you're figuring cross-sectional area you should also consider the potential restriction created where the opening of the duct (snorkel) meets the part called Fender B in the OEM parts catalogs.
Like I said, I sat with the Dyno operator: one run without the snorkel, the next run with - no difference.
The pictures are good. It's nice to know how things work.
When you're figuring cross-sectional area you should also consider the potential restriction created where the opening of the duct (snorkel) meets the part called Fender B in the OEM parts catalogs.
Like I said, I sat with the Dyno operator: one run without the snorkel, the next run with - no difference.
The pictures are good. It's nice to know how things work.