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there is a velocity stack in the airbox that will smooth it out. so goal here is to get as much air as possible into airbox and create a bit positive pressure in there...
Na dadash
OEM "velocity stack" designed to reduce noise as it has a flat bottom with sharp edges, basically it will divert acoustic noise towards two side chambers.
no good at all, actually it the grave issue of rx8 intake apart of....
There are many ways to slice and dice the data, but my main takeaway is that with RAM intake I was able to consistently run faster laps (1 sec faster on average over the whole day - see last table in my post) despite higher IATs (RAM intake day was hotter than OEM intake track day, there was 10-8C delta in coolant temps and 3-4C delta in IATs). I can send you the file with data if you want to play with it.
I mean. You didn't reach higher speeds on the same straights, so whatever made you faster, it wasn't more power.
Na dadash
OEM "velocity stack" designed to reduce noise as it has a flat bottom with sharp edges, basically it will divert acoustic noise towards two side chambers.
no good at all, actually it the grave issue of rx8 intake apart of....
Is that 3" Aluflex you used?
Spoiler
teaser
It can do both reduce noise and improve airflow, you know. Most bellmouths do both, you just don't find many aftermarket providers specializing in intake silencers.
"When it comes to air intakes, everybody seems to be an expert, especially on the internet. People commonly jump to the conclusion that cold air trumps everything. However, thousands of dyno pulls have showed us that cold-air intakes only help when they flow air well. In other words, flow generally trumps temperature.When it comes to small engines, like those in MGBs and Miatas, a 20-to-30-degree increase in intake air temperature usually corresponds with a mere 1-horsepower decrease at the wheels. Meanwhile, flow issues can cost 10 horsepower pretty quickly. To translate this wisdom into strategy: Design your air intake for flow first, then look to lower the intake temperatures.
We’ve also found that a well-placed heat shield can make almost as much of a difference as a full cold-air intake. In our experience, underhood temps near an unshielded air intake often reach 150 to 250 degrees. A heat shield can drop them by as much as 60 to 80 degrees.
A full cold-air intake may lower temps by another 60 degrees, but that’s not as easy as it sounds–especially when the intake is located at the back of the engine, like it is with our kit. With a setup like ours, the throttle body can absorb another 30 to 40 degrees of heat from the engine bay."
Last edited by Nadrealista; 03-22-2021 at 12:23 PM.
So after making velocity stack 360 I decide to increase air opening to the filter box as much as possible which is limited by front end oval oping, wiring loom, radiator fan.
Max size is 110mm aka 4.3" In reality, as I used coupling fitting the id even becomes a bit bigger.
Next, airbox oping becomes bigger to mate and seal over the new fittings. Also, the factory airbox inlet as flow as it has risen up the floor beside all those crossed small boxes.
All noise cancellation boxes shaved, floor soften/melted by a heat gun reshaped to undertray OEM.
I know it does not look good in photos, however, it made a huge improvement to the air flow.
Overall, I impressed and I was not optimistic to feel the difference this much especially on higher RPMs, downsides are noise and labor hours.
Note butyl rubber sealant used not silicone.
360 "velocity stack" OEM air box floor Note air intake floor
now what is your solution for ram air piping/scoop!
I got 4" velocity stack and will test drier hose vs PVC vs silicone elbows. Will see what flows better using my blower and flow meter :-)
in the left corner we have PVC - 4" velocity stack, 4" to 3" elbow and 3" elbow into 3" to 4" rubber adapter.
in the right corner we have Drier hose - 4.5"x8.5" AC scoop into 4" drier hose.
leaf blower is capable of 200mph and 430 CFM, however my meter only measures up to 100mph so testing will be limited to airspeeds <=100mph
Place your bets!
I am also thinking, if flow testing shows that this set up is not optimal, to cut the front bumper and make a ram air opening that will be straight shot into airbox.
Last edited by Nadrealista; 03-24-2021 at 02:41 PM.
looks like a lot of work!
now what is your solution for ram air piping/scoop!
Place your bets!
I am also thinking, if flow testing shows that this set up is not optimal, to cut the front bumper and make a ram air opening that will be straight shot into airbox.
Spoiler
I have some sinister thoughts, not sure yet as I've downloaded a few articles and need to look at them.
So far I am satisfied, even on some RPMs can hear each rotor intake puls like it's on individual TB.
leaf blower is capable of 200mph and 400 CFM, however my meter only measures up to 100mph so testing will be limited to airspeeds <=100mph
400CFM is just a bit more than the engine consumes at the top of the rpm range, so if the blower is only putting out half the speed, it might also be doing half the airflow, which barely gets you half through the rpm range.
Originally Posted by Nadrealista
..cut the front bumper and make a ram air opening that will be straight shot into airbox.
Joking aside, do our cars have MIP sensor and if they do what is the ECU PID code for it so I can log it with my harry's lap timer?
I think that will be more definitive test as our MAF might not read G/S accurately for RAM set up, where MIP will show if there is difference in pressure at high rpm/speed between stock and ram set up.
No manifold pressure sensor.
The MAF reads just fine. It will detect changes in air mass entering the engine between the 2 setups assuming you control for other things that change air mass, like temperature and humidity. I don't know where this idea that BARO modifies the MAF reading came from. That's not a thing.
it’s the baro sensor by the air pump, it actually is a repurposed Mazda manifold sensor but only references baro on the Renesis processor configuration
So today I was able to do some testing of the ram intake configuration with different materials and air scoops.
I used my leaf blower as air source, flow meter to read speed (in mph) of air going in and speed of air going out on opposite end of ram intake tubing, getting consistent speeds with leaf blower was not possible so I will use ratios of speed out/speed in to compare.
Combo of 4" ABS plastic and 4" silicone hose elbows with velocity stack was best, but PVC set up was not far behind.
having velocity stack on the intake side of the hose works best no matter which hose is behind, it improves flow 5 to 10%. the higher the speed the more improvement you get
results with 4" velocity stack and blower 2ft from intake opening
4" dryer hose was able to retain 67%(@60mph) and 63% (@80mph) of air speed coming in.
4" to 3" to 4" PVC combo pipe was able to retain 67% @70mph of air speed coming in.
4" ABS silicone combo was able to retain 70% @60mph of air speed coming in. (could not test at higher speed as blower overheated :-))
so as you can see it is pretty close between last two set ups. I will install ABS pipe/silicone combo and report back after doing some logging on the road and on the racetrack Saturday.
My hi-tech test set up :-)
Pipes tested:
Last edited by Nadrealista; 03-25-2021 at 01:19 PM.
You wasting your time if you are looking at it a scientific way, however, if you are doing it for fun that's another story to catch.
What you need is a Magnehelic Differential Pressure Gauge to measure the effectiveness of your ram(s) on the car at specific speed(80m/h).
I think you might be able to measure something like 0.1000001 psi in the best-case scenario, no even 0.2 ( unite of that gauge is inches of H2O. 3" H2O is like 0.1 psi)
look, for anyone else smart enough to listen it’s really very simple
pressure = force x area
there are two key areas involved; the area of the duct opening and the area of the chassis/airbox opening. The goal is to maximize the opening of the duct to “collect” as much force as possible and transition it as gently, as smoothly, and with as little restriction/loss as possible to the chassis/airbox area opening. Anything less than that only decreases what little is possible to achieve in the first place.
you see NACA ducts dropping down off surfaces or sharp edge openings out in the air stream rather than rounded airhorns on competition vehicles for sound engineering reasons. It’s the wrong tool for the job being used improperly by an unskilled laborer.
End of the story a MAZDA RX-8 REVI RAM AIR DUCT P# S18297HW installed.
feelable lower end torque shift, also upper part must hurt.
Meanwhile, I was at it I add PZ/prodriverx8 grills which surprised me as the lower lip is a few cm's bigger than OEM, hence, sending more airs to rads or
only compensated for grill air restriction.
Not a criticism in pointing it out, but rather your English writing skills are so bad I can’t even really comprehend what it is you’re attempting to communicate.
.
Not a criticism in pointing it out, but rather your English writing skills are so bad I can’t even really comprehend what it is you’re attempting to communicate.
.
Well, I never intended to explain why and how? never did. although one pic is more than 1000 words.
These days no one looking for an explanation all they want is a persiciption.
Nice, now do you have MAF logs before and after so we can actually compare how many more g/s second you get over stock intake for a given speed and rpm combo then modified airbox and finally modified airbox plus RB ram snorkel?
Didn't have time to play with this but I am starting to think that the whole area in front of the radiator is one large ram intake with possibly higher pressure than what you can get in front of the car where ram snorkel would grab air. in front of the car air can escape over the hood and to the car sides where once it enters through the front bumper grill it can only escape through the radiator.
If this is the case I wonder if doing one 90 bend from airbox into that area below with velocity stack will actually force/flow more air into airbox?
Will try to test/record MAF with that set next time on the racetrack and lets see what data shows.
Last edited by Nadrealista; 05-12-2021 at 12:32 PM.
03-18-2021, 06:51 PM
