Nicely done test! However you should have run the tests with the hood closed to see how the throttle bodies performed while sucking hot air from the engine bay. I ran similar tests on a 'busa powered track car, mostly to test different airbox sizes and the difference was huge. constant 70\74°c IATs vs 6°c above ambient is no joke. The airbox is also easier to pressurize at speed and those 0.2psi play a little role as well at the top end of the power curve, something that's hard to replicate on a dyno... but relatively easy to calculate with a properly scaled MAP sensor and some fuel trim\afr\timing datalogs.
Thanks. Thought i had a pinned comment at the top explaining why i tested with the bonnet/hood open, but it seems to have mysteriously disappeared. anyway, I was trying to keep the temps the same, to see the effects of the airbox itself. ya know science says change one thing at a time. The conclusion i come to, was to run the biggest airbox and feed pipe possible (even bigger than what i ran) Or some other way to direct cold air to the inlet runners. In my case, this car usual runs some panels that black off the whole intake side of engine bay. with a big hole beside radiator that feeds cold air. Just it doesnt fit anymore since changed the intake about 50 times. If I ever decided on a intake runner. will go back to that setup.
@@Garage4age Your approach is commendable, it's just that some things work as a system so changing one component at a time may detract from the results' irl relevance. Also keep in mind that the shape of the airbox itself plays a huge role in delivering the same air to each cylinder, in my case I could start off with a boxy section that progressively widens and narrows up to the bellmouths, something you clearly couldn't to given the available space. You could perhaps move the airbox up front, leaving only some form of plenum to close to the ITBs to see how the power delivery changes. Of course if you can shield the ITBs from the rest of the engine bay while delivering a cold stream of air to them then the point becomes pretty much moot since you're effectively using and almost sealed, huge airbox! The math is out there but toying around with airbox sizes etc is a fun experiment nonetheless. On my NA, high revving and over-square engine the difference between the hotter and smaller airbox and this one amounts to a whopping 12hp at 11k rpm... Keep up the good work, i just subscribed to your channel and i'm loving it already!
@@TheDementedMonkeys The only time hot air is being sucked in is at a standstill. Air moves through the engine bay much better at speed. I see where you're coming from to test in worst case scenario to possibly mimic the real life scenario. Ultimately you're right about dynos not matching up very well. I have ITBs and a plenum which is much easier to fill at speed. Dynos always show it low. I had a dyno showing 287whp when all the weight and speed, along with comparison to other vehicles was actually around 310whp on a hot day. I guess it won me some races because I can under report my power 😂 Another issue my car has is the sensor reporting accurate IATs from heatsoak in the sensor itself. This retards timing a degree or two. I don't think the air actually heats up 10 degrees when moving so quickly into the plenum.
@@andyfreeman6865 The problem with engine bays is that there's a huge heater warming the air so even a slow corner is enough to warm up the air that will then be sucked into the engine. Even following a car up close results in warmer temperatures with cold air feeds from the bumper! I never had IAT heatsoak in my applications btw, perhaps you could try moving it up top to mitigate the issue!
What is this, is this youtube? Someone just go straight to the meat of the video without a 20 min vlog before and after?? Keep doing what you're doing, youtube needs people like you.
@@robersniper I've had quite a lot of dyno time over the years. I'd prefer to test and not guess. Buying mods or doing mods without knowing if they really work, to me, is time and money wasted.
I did some CFD on air boxes a few years ago, and you might be able to measure a difference with filters fitted. If you have a single filter each cylinder gets to use work done by the previous cylinder pulling air through the filter, but if it is a filter per cylinder each cylinder does all the work on its own. Depending on the filter it can be
This is super interesting, especially the last intake manifold with the giant plenum volume. You'd think based off conventional wisdom around plenums that it's all gains increasing the plenum volume, but this is the 3rd time I've seen power lost with increased plenum size. Hot Rod/Engine masters did a test w/triple the plenum volume and they lost a bit of power as well, and I did a plenum volume test on my turbo harley where I went from 800cc to 1600cc plenum volume (.5 of displacement to 1.5x displacement....which "should' make a big improvement) and the bike went .05-.1 slower in timed 40-80mph runs. 🤷
When I was looking at ITBs for my Miata I talked with a friend of mine about it who had experience. Here mentioned he'd found a some test data that showed the distance from the start of the bellmouth to the interior wall of the plenum/air box can make a big difference. IIRC they found anything with 3-4in (75-100mm) of the bellmouth started to effect flow in 1L bike engines. Even just an full length filter (i.e. Pipercross) close to the bellmouth caused reduced flow.
I am 100% satisfied with your testing. Your videos are so entertaining and no bs. I've just bought an ignis sport and have been going over all the possibilities to do a cold air i take or replace the panel filter etc etc and have decided f it and just stuck a k an n almost straight to the tb. Does the job and was the cheapest option.
nice test.. on my 2012 accord v6..I kept the stock box, and just removed the button resonator pieces, and placed 4 inch piping in fender well running to front of car with a 6 inch velocity stack. also changed to a better flowing filter..same concept. the box that comes with that car has a velocity stack in the cover that leads to the piping to the engine as well
Good consistency on the dyno, its not always you see that. If you wanted to alter the power curve some alteration to the plenum volume would probably make a difference. For inspiration check out the ol supertouring engines, some of them where mounted in-line like audis.
Very solid tests. I do feel that air box with the extended pipes out the front is missing the major advantage, which is air being forced in while driving. So these numbers could be higher.
10/10 for this experimental work. These tests results have shown ther eis no significant gain or loss either mods. The moral story is do not touch your air box, only if you want some noise...
Awesome mate, that's the best yt channel I've ever seen :) why do you think the Hilux intake reduced the power while the the wooden one didn't have any impact in comparison to the open trumpets
will be the plenum volume. or more so any restriction to the inlet runners. even a tiny amount seems to have an effect on big cam overlap engine. I tested the old hilux inlet/ plenum on it also and was even worse, until cut the roof out of it, so was basically open with just the sides on it
Great job as allways! Moving car will create ram-air effect, with the right intake placement. This will help at higher car speeds and lower engine revs (higher gears). F1 cars used to create (with all the restrictions, super low gearing, and air-hungry engines) approx 5% higher air pressure in air-box, than ambient. I wish You 1M subs, You well deserved it!
@@borutgoli840 You are incorrect. The ram air effect exists at subsonic speeds. In fact, even a ramjet engine will operate beyond about Mach 0.8. Do not pretend to be an expert in aerodynamics when you have only watched a couple of RU-vid videos about it. The minimum airspeed for which ram air compression occurs at depends on the geometry of the ram intake. Lower airspeed intakes tend to be of wide diameter initially and reduce down to a smaller diameter, and need to be fairly long to reduce the amount of air that simply flows around the edges of the intake, reducing the increase in pressure. Their real purpose at these low speeds is to reduce the pressure drop due to large kg/s of air intaken at high engine speeds, boosting the high-end torque. There is also a small compressing effect at lower engine speeds, but this is quite small (as you correctly predicted) because at low airspeeds the air tends to backflow rather than compress, but as I mentioned this can be designed around. That said, the true purpose is to boost high RPM power at high airspeeds, not to boost low end power at high airspeeds.
So fun to watch! Also what other says, I like that you actually test the parts and show it to the world :) I can see the KW, but what about the torque line? Is it really 350 ish Nm or?
Thanks. Torque numbers are at the wheels. hasn't be converted back to engine torque, as dyno is running in road speed mode without tach input. So is engine torque multiplied by the gear ratios and tyre sizes etc. The curve is right and still good for comparison between runs. Doing the maths to get engine torque, it makes 185nm at 6200rpm
One thing to note is that a lot of driveability is not gained from proper pulse tuning, but from avoiding the cockups from anti-tuning. This tends to smooth torque curves. I think it would be a worthwhile test to make a plenum that had an internal texture that disrupted waves rather than reflected them, think small egg carton texture or hammer finish on steroids. Also I'm going to go look at other videos for your headers. Damn sexy but they look entirely too large diameter for the power you are making Subscribed. You're doing awesome work
Shorter ITB'S and a smaller Hilux will be most optimal, for that fuel setup. With that you can put a much extension before the Hilux as you want. If HP is the goal, air flow speed is before volume of air. Definetly worth looking into each cilinder individualy when comparing air induction, ITB alone are not for sure to deliver equal flow. Thank you for sharing your fun.
Congratulations for your test method. ! cold air is the only advantage but with an air box you could add an helmholtz resonator ( if necessary of course ,, lol )
I love the research that you do! I would like to ask you if you are willing to try something different and test out 4 expansion chambered intake runners, it should give a boost effect like acis does if my theory is right and if you can make it the right size and shape to have the resonance boost at the wanted rpm. If i had a dyno and a tigweldingpost + a stand alone ecu and itbs, then that is what i would be testing out all the time. I looked on internet and i can barely find info on this idea so it could be a real premier if you are willing to try this and if it will work
Ive been testing a few things in the background, one of which has a chamber. having the chamber in the runners seems to smooth out the power curve, gets rid of the peaks and dips. but have limited testing on it so far.
Very interesting dyno tests, did you tune the ecu each time you change something? If not the results should be greater special on open throttles. Air box’s for ItBs it’s a black art 🔥
I used to look for change in air fuel ratio pre dyno. This car is tuned in alpha n (throttle position vs rpm) with baro correction. In this mode the ecu cant compensate for airflow change. So when making changes and the afr went lean, generally heading in the right direction.
Id like to see all these tests done with the hood down like a real world scenario where you will be inhaling hot air with just the ITBs, I always prefer with an enclosed airbox with propper cold air induction. Nevertheless, awesome comparison. Love your vids. Keep it up.
hey, Yeah was more interested to see what the box done itself. so was trying to keep air temp same. We all know cold air make more power. This car usually runs a setup that sections off the whole intake side of the engine bay and feeds cold air though a big hole in front of car. so works like a massive cold air feed airbox. since in this vid found that bigger is best. will be going back to that setup once have made the optimal runner setup.
Great Video again, thanks alot! However, I think you shouldve close the hood in order to see if the cold air that is sucked in from the air boxes affects the power output.
Hey, I was actually trying to keep the temps the same, between the open throttles and airbox. As i was mostly interested to see what the airbox itself done. We already know cold air makes more power and judging from what i found here, getting said cold air to the trumpets with least restriction possible is key. be it sectioning off the intake side of engine bay, or building the biggest airbox possible with biggest feed pipe possible
You sir are a god-send! :D This information is so valuable. Mind doing something with exhaust diameter (on both turbo and not turbo cars) and exhaust runner length?
will likely do something on exhaust side once have decided on an intake. probably some time away. in the meantime i have a short vid on my channel that i posted awhile back. where i tested big and small diameter headers
Damn, this engine is so consistent in tests. It was born to be floored. Other engines after 2nd run would probably give less power because of heat. Great video!
Thanks. Its just me rolling into the throttle and the dyno trying to hold steady state, before it starts the run. it holds for a few seconds before starting. so yeah ignore below 2000rpm
Can you make a sort of "twintake" for a single throttle body (Like Forge did for the 2.0 tfsi)... I was thinking of a combo between a cold air intake and a short ram intake connected with some Y pipe or something. You know what i mean :-) Would be interesting.
I have a set of ITB's for my Miata that I'll be installing this winter and I've been pondering putting them in an airbox to see what benefits it might have in the mid-range and if I could broaden the power band.....you just answered that question for me. What are your thoughts about an air box, with properly sized horns inside that? Do you think the lack of airhorns on the Turbo manifold contributed to the loss of power across the board? I thought the common plenum might flow well enough at the top end to match the ITB's, but that definitely wasn't the case. Great videos, I love the tests you do.
The turbo inlet has similar shaped bellmouths inside it. theres a video showing it getting built. The runners are a bit shorter, along with the smaller volume and inlet hole, all adds up to the loss. it works well for its intended purpose
Awesome testing! I've build a box to reduce noise and didn't notice any difference, but I wondered if I really didn't loose something... Thanks for the video!
Now, next is going to have to be variable runner lengths. You could use a valve to swith to a different path. Use a valve to ADD a shorter path to a longer one. And then see if you can get a linear actuator to continuously vary the trumpet lengths.
Try curving the trumpets like the stock 20 valve air box setup. I suspect the trumpets are too close to the airbox wall. I think you need some a couple of inches of space between the runner bell mouth and the airbox..
One piece of data missing: With the airbox are the cylinders all getting the same air? Are there rich/lean holes? It would be nice to see on a flow bench how much the airbox created cylinder imbalance. I wonder if those dips at 5k and 6k that went away on the open itb test were caused by this.
I’d like to see VDs which are 1/3 longer and shorter to see how 2nd and 4th order pulse waves affect the s curve below 3k rpm. Likewise for a 38mm stack vs 44mm stack. Fascinated
This is soo interesting, I'm wanting to build a throttle body system this winter on my b20 vtec and these videos are invaluable. Any idea on tube diameter and throttle plate diameter and total length from head flange to intake tip? It's currently 1996cc 236bhp 177lbft with high comp pistons, stage 2 cams, pnp head, long 421 header, 76mm header back exhaust and revving to 8000rpm limit, 550cc bosch ev14 injectors and a ported b16a2 intake manifold
Pretty hard to say, haven't had much experience with honda engines. Would think you would want at least 50mm throttles, generally will want to go bigger the further from head. My intake is over 300mm long from the head flange, which is quite a bit longer than most people run. From what i've seen is same deal with honda stuff. both a lot to do with fitment. If you can fit it, definitely try getting the length right up there. maybe even longer than what i run since aren't revving quite as high.
@@Garage4age I tried getting d16z6 56mm honda cable operated throttles but only managed to find 70mm so it will have to be tapered down to 51mm and then to 47mm at the head. I don't think il be able to have 300mm length unless I run without filters which I don't really want to do but il see how it goes. Keep the videos up they're quality content.
Hey, I wanted to see what effects the airbox itself had. so was trying keep the inlet air temps the same. The difference in power from air temp could be calculated fairly easily. But will keep it in mind to do a test on in the future
I read an SAE research paper which investigated plenum volume vs. power. It showed that a larger and larger plenum made more power. About 8 times the engine's displacement is where the point of diminishing returns is. It would be interesting to know the volume of your plenum vs. the engine's displacement.
