GR86 Best induction kit for airflow?
- Thread starter grzoostuff
- Start date
grzoostuff
Totally Hooked
grzoostuff
Totally Hooked
- Thread starter
- #23
Looks like another 2 tasty induction kits added at fensport - liking the carbon one which will at least have a bit of heatsink.
Blitz
Blitz Carbon
Blitz
Blitz Carbon
Done lots of testing on the intake system .
It’s easier to lose power than to gain it.
Intake temps are everything on this car.
Ran an open cone non heat shielded setup and you’ll lose tons of power at the expense of intake sound.
You can gain power from an intake but it needs to be extremely well designed with a proper cold air feed.
It’s easier to lose power than to gain it.
Intake temps are everything on this car.
Ran an open cone non heat shielded setup and you’ll lose tons of power at the expense of intake sound.
You can gain power from an intake but it needs to be extremely well designed with a proper cold air feed.
grzoostuff
Totally Hooked
- Thread starter
- #26
This is what puts me off the kn open intake, even though the bonnet should seal it in the closed position.
Maybe the GruppeM is the only one.
Or you can check out what we are making at the moment. It’s made excellent power on Teqiwas Maha dyno under very controlled testing. Thats after testing quite a few previous iterations.
The issue is that any rise in inlet temps isn’t just a couple of HP. It’s like 10-20hp through the entire rpm range too.
They need cleaning when they get dirty and only then do you oil them.
If you apply the oil correctly you’ll not affect the MAF.
Dry filters filter less.
grzoostuff
Totally Hooked
- Thread starter
- #32
Would be interested to see, what are you making at the moment?
You can have a look here at the current design and information
Only thing left to do is make the brackets and the snorkel down to the front bumper.
The gain in power is predominantly between 2–3700rpm and then 6000rpm +
The MAF tube is exactly equal to stock so no recalibration required.
LTFTs are currently sitting at 1-2 % stock…… but…. This is from testing many intake designs some of which reduced power also. We will be driving the car on the final design for at least another 1000-2000 miles to see the effect on fuel trims before going into final production. We are also experimenting with a dual feed but this is showing to be detrimental to how the air flows through the inline filter. We seem to be getting quite alot of turbulence and while this isn’t showing on the dyno , we can feel there is an issue with initial throttle response. With the already increased size of the inlet duct the small additional extra cross sectional area given by the small secondary feed is clearly not having any effect and actually having a negative effect.
I wonder if you can have a version or another adaptor to fit this greddy (https://www.blackhawkjapan.com/products/greddy-12515002 which I and many others have, <+2deg IAT with stock airbox, with some positive pressure to boot cos my resonator blanking cap popped off on expressway hahah) or the "GR86 Cup intake duct" that some have 3d printed. All of these fit direct to the stock airbox perfectly in place of the stock behind bumper elbow. No sense excluding us in the addressable market!
Count me in (provided it's cheaper than HKS and the upcoming eventuri one)!!
Great work and thanks for helping with our platform amidst all your other offering (for much more upmarket brands)!
Count me in (provided it's cheaper than HKS and the upcoming eventuri one)!!
Great work and thanks for helping with our platform amidst all your other offering (for much more upmarket brands)!
Our intake will be coming with a snorkel like that but without the need to modify the bumper foam.
You guys are 3D printing this part ?
We are targeting around $1000 / £1000.
Have a look through our website. This is the very high end without the very high end prices.
To be honest, cutting the bumper foam for the snorkel is painless and it gives a much more gradual ramp for the air into the air box without (hopefully) any BL separation. And I hope it doesn't block the rad flow (and the many of us with oil cooler there). I get positive pressure without the greddy being in the flow (https://www.gr-zoo.com/threads/white-gr86-from-singapore.1129/post-87792) cos it just feeds off the stagnation point. But I guess (and can understand) why others may want it in the flow, so if its a full snorkel blocking the radiator, i guess i will just trim your snorkel like I did the greddy hahah. Another hopeful request is for it not to interfere with the HKS Oil cooler duct, which again some of us have. You can see I needed to trim the greddy snorkel further as it stretches too much to the port side of the car https://www.gr-zoo.com/threads/white-gr86-from-singapore.1129/post-95306 . Hope you dun mind my suggestions, just trying to maximise your addressable market.
Anyway if it helps, for a stillborn DIY project i wanted to do few months back on the intake (basically use back the stock MAF tube and put an open pod filter in a box at the current plastic airbox location). I did a CFD of the stock air box and two different air filters mouth diameters (and thus a low and high convergence ratio/"bellmouth") with same MAF plane and MAF tube inner diameter and at 160g/s air flow (iirc that's the airflow reported from the car OBD2 at 6000rpm). Solving for pressure loss thru. Basically the more the convergence ratio ie more "bellmouth", the thinner the BL within the MAF area and the more even the flow (yes duh, classical theory). But the bigger bellmouth one had the average flow speed so much lower (see the lighter colour, same colour scale) compared to the stock one (which yes was uneven and "ugly") that I was concerned I needed to recalibrate the MAF (which I didn't want to cos I am anal (not that type) and afraid of going down the rabbit hole with refining in precisely at flow rate (which i did with my Evo years back, involving lots of logging and scatter plots and iteration yikes) cos I love my low LTFTs which are (like you reported) within -2 to +3% only now, for all 4 learn sites ie idle, low load, high load and overrun. So I aborted the project cos with the risk of having to recalibrate the MAF, I only getting 0.05% lesser pressure loss from stock. Although yes I still have the stock post-MAF elbow. Guess most of your benefits came from removing that elbow. Yay!
Most people recalibrate the MAF at high rpms/flows only and on dyno and to get good power numbers, but the calibration at flows that one reaches during normal driving and tip in conditions are equally if not more important cos thats drivability and you dun want too much STFT spikes (which people will just add lots of tip in enrichment to cover up...). But i digress. Anyway thus I was curious with the LTFT you are getting and nice to know they are nice and low. Congratulations!!
Anyway if it helps, for a stillborn DIY project i wanted to do few months back on the intake (basically use back the stock MAF tube and put an open pod filter in a box at the current plastic airbox location). I did a CFD of the stock air box and two different air filters mouth diameters (and thus a low and high convergence ratio/"bellmouth") with same MAF plane and MAF tube inner diameter and at 160g/s air flow (iirc that's the airflow reported from the car OBD2 at 6000rpm). Solving for pressure loss thru. Basically the more the convergence ratio ie more "bellmouth", the thinner the BL within the MAF area and the more even the flow (yes duh, classical theory). But the bigger bellmouth one had the average flow speed so much lower (see the lighter colour, same colour scale) compared to the stock one (which yes was uneven and "ugly") that I was concerned I needed to recalibrate the MAF (which I didn't want to cos I am anal (not that type) and afraid of going down the rabbit hole with refining in precisely at flow rate (which i did with my Evo years back, involving lots of logging and scatter plots and iteration yikes) cos I love my low LTFTs which are (like you reported) within -2 to +3% only now, for all 4 learn sites ie idle, low load, high load and overrun. So I aborted the project cos with the risk of having to recalibrate the MAF, I only getting 0.05% lesser pressure loss from stock. Although yes I still have the stock post-MAF elbow. Guess most of your benefits came from removing that elbow. Yay!
Most people recalibrate the MAF at high rpms/flows only and on dyno and to get good power numbers, but the calibration at flows that one reaches during normal driving and tip in conditions are equally if not more important cos thats drivability and you dun want too much STFT spikes (which people will just add lots of tip in enrichment to cover up...). But i digress. Anyway thus I was curious with the LTFT you are getting and nice to know they are nice and low. Congratulations!!
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What an absolutely brilliant post !
It’s very nice to see people like yourself on this forum posting such detailed information and doing CFDs.
We aren’t really sure why people rescale the MAFs.
One our team members is a very well known and skilled tuner specialising in total recalibrations for forced induction and running without MAFs.
Rescaling MAF tables on cars with just an intake and a few bolt on mods is the wrong approach completely. You’d need to recalibrate the entire part load and full load fuel / load tables otherwise like you have said you run into issues with drivability and fuel trims.
Why not just change the full throttle fuel maps to achieve the desired result and that doesn’t affect anything else ?
Back to the CFD analysis. Yes the larger Venturi stacks will always give a smoother flow with less turbulence but show a lower air speed.
However, this isn’t the entire story and in reality they larger Venturi stack works much much better for both flow and power when you take into consideration the intake pulses and the rest of the system working together.
You can also have a bend before the MAF so long as you don’t get flow separation from too much of a steep bend.
GRistopher
Totally Hooked
- Oct 23, 2023
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- 1,133
You guys are like 2 peas in a pod. A pod that has been designed for optimum airflow. 
