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Well I tried out the larger throttle body last night and it didn't work out well. I need to make a minor adjustment to the adapter which is easy, I just cut out what I needed to make room to use the one I already had. All my other measurements worked fine. I ran into problems trying to run the 75 mm throttle body, I think the adjustments needed are just too far outside of what the ECU will do. I will see if orange virus can help get it to set right.
I don't claim to know much about how a MAF works or how the ECU uses it to calculate the mass of the air that is flowing into the engine, but if you change the diameter of the intake tube and the throttle body, doesn't that affect the constants that the ECU uses to calculate the mass? By that, I mean if the tube is 2.5", the ECU uses that temp and the speed of the air passing the MAF to calculate the actual volume of air coming into the TB. If you increase the tube to 3", the ECU is now using the wrong diameter to determine the volume of air.
Does that make sense or am I just too ignorant to understand the calculations involved?
I don't claim to know much about how a MAF works or how the ECU uses it to calculate the mass of the air that is flowing into the engine, but if you change the diameter of the intake tube and the throttle body, doesn't that affect the constants that the ECU uses to calculate the mass? By that, I mean if the tube is 2.5", the ECU uses that temp and the speed of the air passing the MAF to calculate the actual volume of air coming into the TB. If you increase the tube to 3", the ECU is now using the wrong diameter to determine the volume of air.
Does that make sense or am I just too ignorant to understand the calculations involved?
you are absolutely correct. if you change anything that goes into the engine to produce power, the ECU will be miscalculated. to correct this, you need to tune your car. basically speaking, a tune can "recalibrate" your car. in this case, since you have more supply of air, you would tune your car to release more gasoline to combust with the excess air. if it is not tuned, the excess air will flow through the engine, without combustion, and make a "pop" out the exhaust. anything not used will expel from the exhaust.
basically: air + fuel = combustion = power
an excess of air is called "lean" - makes a popping noise of the exhaust
an excess of gasoline is called "rich" - excess fuel will burn out your exhaust and create fire
My old IS300 had an SRT intake which had a 3.5" intake tube vs. 3" stock. It had to have a piggy-back ecu to run properly otherwise the engine would throw a CEL.
Getting back a bit late but an update is an update.
I have been driving with the enlarged throttle body and adapter without problems. I did back to back to back testing and there was something like an average of 1.5-2 g/sec gain with the larger throttle body. This is a near negligible gain but I will take it. I think the manifold is the main restriction here, the neck that runs around the back is smaller for long enough to negate a larger throttle body. I have been wanting to do something with the manifold for a while now and I think that I can pull something off. I started by wanting to make a manifold but my printer is too small, so now I am working on making a printer large enough to print about anything I could need. I have been poking at it slowly, and hope to have something to try out by the end of the year.
Getting back a bit late but an update is an update.
I have been driving with the enlarged throttle body and adapter without problems. I did back to back to back testing and there was something like an average of 1.5-2 g/sec gain with the larger throttle body. This is a near negligible gain but I will take it. I think the manifold is the main restriction here, the neck that runs around the back is smaller for long enough to negate a larger throttle body. I have been wanting to do something with the manifold for a while now and I think that I can pull something off. I started by wanting to make a manifold but my printer is too small, so now I am working on making a printer large enough to print about anything I could need. I have been poking at it slowly, and hope to have something to try out by the end of the year.
I'm not sure if this will help you out at all, but back in December, OV made a post about modifying the IS350 intake manifold. You could ask them about progress and if they are still making progress on it.
I tried this mod today. As I have two tops of the OEM air box. One is completely gutted with the charcoal filter delete. I often wondered if adding some kind of air flow straightener to the MAF would help. With the gutted top it does help in throttle response, but the throttle always lags around 60-80 mph. Like if it can't make up it's mind to downshift. So today I got my other top, and started to gutt it leaving the last layer of plastic mesh. See pics below. Once I got it back on the car it did kind of felt sluggish driving around. I didn't reset the ECU just dropped it in. Fast forward later I took it on the HWY 60 miles round trip it adjusted the hard pulls consistently. From 60-80 mph the car would just drop gears and go. I got home and pulled the top off to make sure everything was still there, and didn't get injested by the engine. As of now I'm going to wash my Dryflow filter and let it dry over night. In the morning I'm going to reset the ECU and monitor it for a couple of weeks.
I'm sure the Yoda engineers did this already but it would be interesting to see flow numbers through the heads and complete intake assembly for each cylinder. That pancake plastic manifold with its oddly shaped port match makes ya wonder if all cylinders flow the same? Guessing yes.... but.
Is there anything to be done with port matching upper intake to lower intake to the heads? I'm not saying hog it out, just make it match so there are no reversions impairing flow.
D i c k, in another thread we talked about PPE primary pipe size being larger than needed for the volume of air this engine moves. I wrote PPE 2plus weeks ago about getting smaller ID primary pipes but NO response. Can anyone say for certain that 250 headers exist and are smaller ID than 350 headers? If so, what is the value. Their website does not specify.
Getting back a bit late but an update is an update.
I have been driving with the enlarged throttle body and adapter without problems. I did back to back to back testing and there was something like an average of 1.5-2 g/sec gain with the larger throttle body. This is a near negligible gain but I will take it. I think the manifold is the main restriction here, the neck that runs around the back is smaller for long enough to negate a larger throttle body. I have been wanting to do something with the manifold for a while now and I think that I can pull something off. I started by wanting to make a manifold but my printer is too small, so now I am working on making a printer large enough to print about anything I could need. I have been poking at it slowly, and hope to have something to try out by the end of the year.
Dude! Would you be up for sharing some of those files? I've been wanting to model a new intake manifold but have been to lazy to pull mine of to measure it.
Very fascinating, I’ll subscribe to see updates to this thread.
I myself am running an intake setup like the k&n typhoon (I have the actual k&n typhoon kit), but I swapped the oiled k&n filter for a AEM 21-203D-XK universe dryflow clamp on filter with the AEM filter sock/wrap, and wrapped the entire chrome intake tube with heat reflective tape and exhaust wrap. I also changed out the default hose clamps for some premium Breeze aero-seal constant torque liner clamps(I have a few extra if someone needs some).
I tried making my own heat shield box by reinforcing the flawed/half assed k&n typhoon configuration in regards to sealing off the intake area from the engine bay heat but i too only managed a half assed solution.
I still have a brand new heatshield products Thermaflect shield 14”x20” that I’m not sure what to do with, or how to incorporate it properly to my intake setup. Something tells me to use it on protecting my interior cabin from the underlying exhaust heat but I’m not sure where to put it so I am a bit stuck on what to do with this piece.
With all my stupid intake mods and project attempts the car isn’t any faster but I like to think it is. The reflective tape and exhaust wrap around the intake tube does make a noticeable difference in traffic light rough engine idle issues and it seems quicker off the line probably because of the decreased ambient engine bay temps when at a standstill. Either way it was fun tinkering.
Oh I also forgot to mention I swapped my OEM MAF out for a JET Performance MAF specifically made for the Lexus IS250/350. It for sure didn’t hurt and I’m pretty sure it helped the A/F ratios.
i also have a invidia midpipe and Tanabe Axleback that I believe have a slight impact on the air fuel ratios so please take that into account as far as how the aftermarket JET Performance MAF sensor helped my case.
Oh if anyone is interested in a Tanabe Axleback please let me know, with the intake and invidia midpipe it’s just too loud and I’m getting too old for this level of exhaust noise lol. Sadly wish I kept my stock exhaust but oh well. Anyways cheers guys
@DickH , any new updates to increasing your MAF g/s readings with your engine mods? I recall you previously having issues with your AFR being too lean but not sure if you ever had that resolved.
I personally am still tinkering around to determine if the 2.75" JoeZ intake pipe is the better performance pipe compared to the 3.00" 3IS F-Sport Intake pipe w/ Sound Generator. The research never ends! 😁
I haven't really messed with much with winter and other things going on. I have a larger 3.5" intake ill install and try out, but the maf reading wont be right. I am thinking about swapping it out on a dyno this spring to see what kind of difference it makes vs the 3" intake I made. Worst part about this is I no longer have the oem airbox to compare against.
... ... ...
I did get to play with the 3.5" intake and on another day tried the stock setup again and I can say that there are decent gains. Stock intake flowed ~220 g/s by ~7500rpm and my highest with the 3.5" was 239 g/s. Previously with my custom 3" intake my peak g/s would range from 228-234 depending on the day, the 3.5" seems to be a slight improvement over that... ... ...
Numbers from a stock 2013 2GR-FSE.
MAF sensor g/s 225 @6,533 RPM whereby the AFR dropped to 12.0 in PWR mode. Need to repeat in normal mode.
@DickH DickH did I read that right, 220 g/s at 7.5k ? No typos? @redspencer Redspsencer can you post up your numbers with your current mods? @MikeFig82 mikefig I know yours is a 250, can you also post up your numbers with your current mods?
If that is what I typed, that is what was read from the obd port. Since changing my exhaust I have seen low 250s and I believe when it was all stock I wasn't breaking 210g/sec. I am not sure if we can directly compare maf readings due to differences in elevation and whatnot. I remember looking into it at some point and I would gain something like 3-4% just from the difference in air density if I visited redspencer.
05-06-17 | 03:12 PM
