I'm with you on this one, but would like to see the numbers it gives.

 

OK guys, I have hard data about this mod. I did it last Sunday and you can feel the difference right away. First of all you can hear the intake way earlier, from around 2K RPM. Just the sound makes you believe that your car is faster, maybe more HP I thought? So I went to the track today and tried my ISF. I did about 7 runs and I knew there was something wrong, my times were a little bit slower than 2 months ago, I was runing 8.7 at best in the 1/8th mile. Even though I could swear that the car was faster, the slips were saying otherwise. For my 8th run I decided to take this mod back to the way it was stock and I immediately picked up 2 tenths! I couldn't believe it so I did 6 more runs and I ran consistently 8.5 (all runs). My trap speed also jumped from 84MPH to 86MPH. So I'm taking the intake back to the way it was, and I'll enjoy that lovely sound from 3600RPM, not before.

 

Good Data, I suspected low end torque would suffer due to the openess and I would probably buy this however. I did dyno the car with the flap open and the new Amsoil filter and saw a 4.4HP relative gain and 4 ft lbs of torque with a good increase all the way through the band. I was expecting this to lose some bottom end, but this was not the cas statically on the dyno. I suspect the pressurization of the airbox through the small path will probably help in actually driving. When I get back home, I will get some gtech data and see where it ends up with and without.

Fig

 

Thanks for the feedback...I tried it as well and although it felt like 'sport' mode was on, it hesistated a click when stomped. I restored to factory where I will leave it until a more thought out mod comes out.

 

Nice to get some more solid data. I honestly think that if this "mod" would yield gains that easily, then Lexus would have done it this way in the first place with no additional cost at their end. So there must be catch to this.

 

So what your stating actually contradicts against the tracktime he puts down interesting....

Is that 4HP or 4whp?

 

This is some great real world data. However, I do have a couple of questions:
1. Was the flap mod done RIGHT BEFORE doing the runs, then put back to stock after finding out the slower times, or was the flap mod done for awhile before doing the runs? The reason I as is to see if the ECU had properly compensated, for what I would assume increased air from the opened flap.
2. Are you still running the stock air filter, or an aftermarket one (K&N or Amsoil)?
3. Have you done the vaccuum cap mod as I showed in the intial post, or just disconnected the plug for the flap accuator? The reason I went with a vacuum cap mod rather than disconnecting the plug was because of my concern that disconnecting the plug may alter what the ECU was reading and change something around in terms of the A/F ratios or something else. By just doing a vacuum cap to plug it off, it doesnt change anything electrical, I would assume just fools the ECU to thinking that it's still stock. Once again, this is all hypothetical.

I returned my airbox to stock after reading your post last night and driving the car this morning, to me at least, seems sluggish compared to with when the flap was open. Fig also showed a 5hp gain and to me, I agree with this that there is a increase in HP and torque with the flap open. However, I know that Fig also has a Amsoil filter in place.

Inregards to why the factory that this intake flap was put into place, I believe it to be mainly for the purposes of perserving the luxury and quietness of the car in the lower RPMS. I don't believe it to be due to performace reasons...once again, hypothetical. I don't see how having the flap closed in lower RPMS can increase the HP or torque, or for that matter increase it in the higher RPMS when it opens.

 

Here are my answers:

1. I did the mod last Sunday and drove that way for about 250 miles before I went to the track.
2. My car is completely stock except for tints.
3. I did the mod just as you showed it on the first post, so it's confirmed, I used a vacuum cap.

As I said I thought my car was faster. When I went to the track 2 months ago the air temp was about 86F, so this last Wednesday I was expecting better times because of this mod, and also because air temp was 66F. Two months ago I was runing 8.65@85MPH in the 1/8 mile, and you can imagine my surprise when this week my best run out of the first 6 passes was 8.75@84MPH. I wondered if the mod had something to do with being slower when I should be faster (at least because of the cooler night), so I removed the cap and connected the hose back. I had another pass right away and bam! 8.57@85.5MPH. The following 5 passes were similar. This experience showed me that the mod doesn't help performance-wise.

 

Thanks for the quick response. I guess there must be something to the design of the stock airbox. I just can't figure it out and to a certain degree it doesn't make sense...you figure that you'll make more power down low with the flap open, but I guess that's not the case. I guess the only way to have definative proof is to dyno it, but your data is just as good. I'm going to however, likely keep the secondary flap open...I like how it gives a better throttle response when it's open...it feels easier to drive in the lower RPMS, for me atleast.

 

what were youre 60 foot times.. maybe you had more wheel spin during the launch ?
or maybe que amsoil filter was ofsetting any negative drop need more testing......

 

My 60 foot times were always around 2.1, with and without the mod. Wheelspin is there, I can't avoid it, these stock Bridgestone don't help launching the car and the track isn't the best either.

I don't have any aftermarket part on my car, not even the air filter, I'm stock.

 

cool thanks for the info

on the filter i was actualy refering to therealfig Dyno experiance of the 4hp gain.....

 

What we need is a before and after dyno of this mod with a completely stock car. Fig's dyno I believe was before and after the Amsoil filter, both times had the secondary flap open.

 

yeah, I beleive my gains were more due to the filter being in place and also removing the charcoal filter. My thoughts were that I did not want to nitpick on 4 HP. give or take, its only 4HP, almost not worth the argument. Like I said, I can beleive that the tighter air passage at low RPM can help, but I do prefer the growl when its always open. I think I would like to augment the system and figure out an even more progressive way to utilize the vac actuation while maintaining the throaty sound. The car is still faster that I can use in short burst of road I get to play on .

 

I removed my stem caps from my wheels and I swear I picked up 2 hp down low. This is a great and inexpensive way to mod your car

Don't reinvent the wheel......just let the wheel roll