When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
On my 2IS, I've used both a modified OEM lower intake box (hole cut up front) and the official F-Sport lower intake air box. Below is a side-by-side comparison to give you an idea of the design differences which may help with your future modification if you decide to go that route on your 3IS. I believe I used a power drill with drill bits when I made that hole years ago.
I am interested to cut hole to my 3is lower air intake box. Do you know the exact dimensions of the extra hole on F-Sport lower intake air box?
I am interested to cut hole to my 3is lower air intake box. Do you know the exact dimensions of the extra hole on F-Sport lower intake air box?
don't know exactly dimensions, but didn't really matter, for me. The hole i cut was smaller i believe, and i go the desired sound. Mine was probably if I had to guess 2.5 in wide and 4-5 in long..
I am interested to cut hole to my 3is lower air intake box. Do you know the exact dimensions of the extra hole on F-Sport lower intake air box?
I don't recall the exact dimensions but it is within the range that Homer350 mentioned.
I HIGHLY recommend you making a secondary intake hole as it's not just for induction noise. I've done multiple datalogs to determine if there's any performance benefits to be had with the secondary intake hole located behind the headlight and confirmed there is a noticeable increase in intake air flow (approximately 7-10g/s higher) at peak RPMs compared to the enclosed OEM intake box.
I also confirmed that there is no difference in IAT readings with the secondary intake hole in multiple scenarios so heatsoak increase is not a concern.
I don't recall the exact dimensions but it is within the range that Homer350 mentioned.
I HIGHLY recommend you making a secondary intake hole as it's not just for induction noise. I've done multiple datalogs to determine if there's any performance benefits to be had with the secondary intake hole located behind the headlight and confirmed there is a noticeable increase in intake air flow (approximately 7-10g/s higher) at peak RPMs compared to the enclosed OEM intake box.
I also confirmed that there is no difference in IAT readings with the secondary intake hole in multiple scenarios so heatsoak increase is not a concern.
I love when the things I'm thinking of (more induction noise for my 3IS350 Fsport) just show up in this forum; thank you to all who have already blazed the trail, time to order my F-sport filter and drill/dremel a hole in my lower intake box!
I don't recall the exact dimensions but it is within the range that Homer350 mentioned.
I HIGHLY recommend you making a secondary intake hole as it's not just for induction noise. I've done multiple datalogs to determine if there's any performance benefits to be had with the secondary intake hole located behind the headlight and confirmed there is a noticeable increase in intake air flow (approximately 7-10g/s higher) at peak RPMs compared to the enclosed OEM intake box.
I also confirmed that there is no difference in IAT readings with the secondary intake hole in multiple scenarios so heatsoak increase is not a concern.
Thanks for the insightful information. I managed to cut a rectangular hole in my lower intake air box today with my rotary tool. Already noticed increase intake noise above 4.5k RPM. I hope this will be a performance gain.
Quick update after modifying lower intake air box:
I've noticed quicker throttle response in normal, sport and sport+ mode. Overall the car feels quicker than before, even though I already have RR Racing tune, Invidia full cat back exhaust system, F-sport full air intake system and run on E10 fuel. The car now accelerate like the way how my old 2IS350 accelerates from a dig. It sound loud and throaty way better than synthetic fake sound from the stock sound generator. I don't think I would ever want to go back to stock intake sound generator now.
I don't recall the exact dimensions but it is within the range that Homer350 mentioned.
I HIGHLY recommend you making a secondary intake hole as it's not just for induction noise. I've done multiple datalogs to determine if there's any performance benefits to be had with the secondary intake hole located behind the headlight and confirmed there is a noticeable increase in intake air flow (approximately 7-10g/s higher) at peak RPMs compared to the enclosed OEM intake box.
I also confirmed that there is no difference in IAT readings with the secondary intake hole in multiple scenarios so heatsoak increase is not a concern.
How long did it take (in seconds, minutes, etc ) between two pulls for the same setup?
Did you test a scenario of “sitting at the traffic light” where you stop, sit with the engine running for 30-50sec and then immediately do a pull.
Engine will significantly warm up the air inside the engine bay during that time, and it has to get sucked into the air box the moment you start moving again.
Also, what were the outside air temperatures when both of those data sets were collected?
Thanks for the insightful information. I managed to cut a rectangular hole in my lower intake air box today with my rotary tool. Already noticed increase intake noise above 4.5k RPM. I hope this will be a performance gain.
Thats great news... And a very effective modification.
We started cutting holes in the 2 IS air boxes back in 2008
Quick update after modifying lower intake air box:
I've noticed quicker throttle response in normal, sport and sport+ mode. Overall the car feels quicker than before, even though I already have RR Racing tune, Invidia full cat back exhaust system, F-sport full air intake system and run on E10 fuel. The car now accelerate like the way how my old 2IS350 accelerates from a dig. It sound loud and throaty way better than synthetic fake sound from the stock sound generator. I don't think I would ever want to go back to stock intake sound generator now.
The FSport sound generator is a piece of plastic attached to the intake that slightly amplifies and directs the intake sound towards the firewall of the vehicle.
“Synthetic, fake sound” like you said would be playing fake intake noise through the vehicle speakers like so many cars do.
I think fsport stock intake sounds really good
I think ur butt dyno is convincing you that what is likely a 1-2hp gain, if that, has made your 3600 pound Lexus “quick like a 2is and better throttle response”...IMO.
How long did it take (in seconds, minutes, etc ) between two pulls for the same setup?
Did you test a scenario of “sitting at the traffic light” where you stop, sit with the engine running for 30-50sec and then immediately do a pull.
Engine will significantly warm up the air inside the engine bay during that time, and it has to get sucked into the air box the moment you start moving again.
Also, what were the outside air temperatures when both of those data sets were collected?
I kept the conditions, timing between pulls, gear used (mainly 3rd gear), and ambient temps very consistent between both setups and time of day (early morning for the low temp WOT pulls and noon timeframe for the high temp WOT pulls) in order to minimize variables with the weather conditions which would impact the comparisons. I have the specific details of my multiple months of datalogs buried in my build thread if you want the full info: https://www.clublexus.com/forums/bui...ld-thread.html
My heatsoak comment is based on testing the IAT for both setups under the exact conditions and time of day (ie sitting idle for 3 minutes at a traffic light at noon to get readings and then driving to see how quickly the IAT reduces; letting the engine and intake heatsoak in the garage for 30 minutes and getting initial readings, cruising on the freeway at a certain speed with similar ambient temps, and other scenarios using both setups).
I kept the conditions, timing between pulls, gear used (mainly 3rd gear), and ambient temps very consistent between both setups and time of day (early morning for the low temp WOT pulls and noon timeframe for the high temp WOT pulls) in order to minimize variables with the weather conditions which would impact the comparisons. I have the specific details of my multiple months of datalogs buried in my build thread if you want the full info: https://www.clublexus.com/forums/bui...ld-thread.html
My heatsoak comment is based on testing the IAT for both setups under the exact conditions and time of day (ie sitting idle for 3 minutes at a traffic light at noon to get readings and then driving to see how quickly the IAT reduces; letting the engine and intake heatsoak in the garage for 30 minutes and getting initial readings, cruising on the freeway at a certain speed with similar ambient temps, and other scenarios using both setups).
Was there heatsoak? Couldn’t find the answer the build thread has like 800+ posts.
Was there heatsoak? Couldn’t find the answer the build thread has like 800+ posts.
No difference in IATs when I datalogged in various idle conditions and as the car went into motion, the rate of IAT reduction was approximately the same.
My hypothesis is that the plastic material for the intake box will absorb the engine bay heat (affecting recorded IATs) and the secondary intake hole has no noticeable impact to further increasing heatsoak.
02-21-19, 12:24 PM
