ITB Basics for Miatas (FM Live) 

tripping the noise limit at Leguna Seca from intake noise is quite the achievement, haha

Great video. Presenter style helps a ton. Thoroughly enjoyed this and will now browse your library for more 👍

Excellent video thank you! Greetings from Greece

Love this. Thanks for the information.

75mm and Up for velocity-stacks are usually good for my 1.6

11:18 Electromotive ecu tps/map "blend". There are many others versions from others companies that can deal with the idle tuning without using a two or four wire iac. Thank you for share such great content I am learning a lot!!

For anyone who's interested, tFM's tower brace fits over the Jenny kit in the NA/MK1. I'd highly advise using a plenum on these things as they can be too loud for dedicated street use, if it's a weekend car that hits the track from time to time it'll be fine (because you drive something else daily) but as a daily driver, ITBs are rough. The only one I've found that will fit on RHD cars is the Pipercross PX600 Plenum. It's not cheap but it fits. They're great for NA power but I'm tempted to revert back to a stock intake purely for the drivability factor. A good intake, exhaust and a remap does a lot for these older cars.

Very nice , was thinking of ITB not any more. THANKS

Dude nice m5 in the background! I've got a 95 miata and e39 530 myself!

I always wondered why cars used butterfly throttles instead of slides like the old motorcycles I grew up with. Then I read that, when developing the carburetor for the first Yamaha YZ400F four-stroke, they had to support the slide on roller bearings due to the short, sharp, ferocious intake vacuum of a very powerful big-bore 4-stroke. Then it made sense. I was used to 2-strokes, which have a very long intake duration but only mild vacuum pull. With certain highly-developed reed-valve engines, intake flow can be almost continuous on a single cylinder, with minimal sharp pulsing. Not only that, but a 2-stroke carb slide is always slathered in oil, whereas a car will see "dry" gasoline at best and humid Florida air at worst. My fantasy of putting 8 Mikuni round-slide carbs on a V8 were dashed. I want a 2-stroke Miata...

I owned a ‘95 for 18 years. 😊 Loved it so much.

I can't express how happy I am that I found this video. I bought a T3 billet aluminum 1.6 flange for Toyota AE101 ITBs a few years ago and never got around to installing them.

The e39 just chillen in the backround👌

"Original Live video recorded 2-21-21." Wow, time travel!

What a tease, Keith! We need the name of that intake trumpet profile!!!

In Japan alot of Mazda Miata drift guys use ITB , shaved head and a high lift cam ....the cost is about same as turbocharger setup , without all the engine work .... both setups get you to 200 whp . Then it all turns into a never ending money pit .

Hi Keith, bit late to the party but I think the shape you are trying to remember is called an "Aerofoil", I have studied some papers on ITB bellmouth design as well for my 13b ITB Miata and I kept seeing a comparison between that, a regular parabola and a basic radius. Interestingly enough the parabola seemed to outperform the aerofoil under normal conditions. I tested different lengths back to back on the dyno, but I guess my overall runners were already pretty long because the difference was almost negligable. Great and insightful video!

I think you guys might have been thinking of a Cycloid curve, or maybe specifically the Brachistochrone at 34:23!

if you are interested in this it has gotten a lot cheaper than you would imagine. Find a speeduino standalone ecu and then get some gsxr itbs. next get an adapter manifold, i 3d printed mine out of carbon fiber nylon you could likely pay someone ear you to print one for you the files are probably out there online. hooking them up wasnt that hard but tuning them in was a slight challenge.

ITB enthusiasts check out Garage 4AGE channel, he is constantly testing different setups.

... hello, e39 M5. appropriate backdrop for an ITB video, given they have ITBs.. ;)

Also Jenvey far as I can tell is a set of modified DCOE Webers-may be a budget way to do that but the DanST setup is likely cheaper and more available

I had a friend in north carolina who was running itb’s on a stock ecu with a butter smooth 400rpm idle. car was very modified

hi thanks for all your contents, i have learned an awful lot off of them :) it seams like there is no video about cam upgrades. is there any chance you guys might do it in the future? thx

Also had an E39, pulled like a beast, but ultimately glad I got rid of it, too many little issues everywhere.

How would a plenum and intake tubing affect ITB torque and power output? Same as runner length - larger volume shifts the torque band down the RPM range, and the opposite for lower plenum/intake tubing volume?

Thx for the video. Does an engine need a retune if changing trumpet/horn lengths on an ITB set up?

Any special considerations for Mazda K8 v6 (1.8L) sportscar used for sprints and hill-climbs ? I plan to use the stock plenum...

Good video overall, but there's a few points I could add. First, about the ND, I think the only logical way of running ITBs would be to keep the OEM DBW throttle tucked in a corner somewhere. You could then add your own TPS to the original throttle (or just snoop on the original sensor) and use that signal to drive your own throttle motor on the ITBs through something like an Arduino or similar microcontroller. Obviously, you would need to build an intake system that can work with the OEM MAF sensor. The MAF signal might also have to be intercepted and processed depending on the difference in flow between the OEM intake and the ITB one (especially on the ND2 if no one can figure out how to tune the OEM ECU). Of course, you could skip this whole rigmarole by doing the sensible thing by ripping out the stock ECU and replacing it with something reasonable like a Motec or Link ECU. As for tuning ITBs, there are only two reasonable approaches. One is using a MAF as the OEMs do; BMW and Nissan on the old Skyline Gtr are good examples. Or two using an Alpha/N strategy on an aftermarket ECU. High Performance Academy has a good webinar on the subject here: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-9XvXfX3QhlU.html . The key points being that you need to set up a good fuel table (whether it be VE or MS based) with high resolution brake points on the TPS axis close to idle, something like 1 or 2 percent increments. Then, if you are running a turbo you can set up an auxiliary fuel table for high boost operation based on MAP, or IMAP to EMAP ratio if you have it.

Hey, make that two guys and probably a lot more.😆

Keith, your timing couldn't be more perfect. I just spent a year developing an ITB kit for my NSX and all of the issues you mentioned couldn't be more true. We got it sorted and it's running great as a street driver weekend track warrior. I hope you don't mind I plugged a little mention of you here ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-mODPROKLxzQ.html

How did you add the IAC to your itb? Did you use the 98-05 miata iac? How did you route the hose from the IAC? Please and thank you in advance

Does it matter if the ITB's and runners enter straight into the cylinder head or must they have a sloped downward angle? I have seen pictures of both styles.

Wasnt expecting to see an e39 m5 on flyin miata! 😂

Is there a way of retaining EGR with ITB's. Like plugin' it into vacuum box or intake plenum (before throttle bodies)? I need to retin it in order to stay emmision legal in europe.

My hayabusa runs two different length intake horns ( stacks )

If they were boost referenced I.e. turbo fed where does vacuum come from for brake booster Between filter and turbo ???

I think itb’s on an nd would be easier as it’s direct injected

Do yall offer ITB's for sale on the site for the NA or NB?

I had my 86 rx7 13b 6 port s4 na with a side draft dcoe itb China Jen berg with a merger f250 intake arm with the air flow meter run, stock injectors... kinda street port. I have a video. I’m tryna get it running again it blew a coolant jacket iron lip... because I swapped the jacket on the rear with some old tip from a old website from the catalog mpc mastercar... I regret it.

Could an ITB system be developed with a common plenum before the horns and throttle butterfly's that can then use the MAF and a single filter? Sorry posted before I saw the plenum mentioned.

how do you balance ITB's?

never hear one live but do they make more audible lifter noise as the youtube videos make it seem?

Doesn't the plenum restrict as much air as well as the stock intake pipes and manifold? Is the only.advantage then just response?

Anyone know how one could/would rig the Jenvey ITBs and their airbox to a (modified) stock air intake, with all the pipes, MAF-sensor (mine is an NA6) and stock ECU? Has it been done?

have you used or tested Jenvey MX5 throttle body kit

If you run individual throttle bodies how do you get the break booster to work

Hi Keith I have a 2000mx5 in mint condition all original except tecna coilovers on it never driven only 133000klm im in nfld would you like to take it in the nl targa 😊

Is FM planning on adding ITBs to your catalog?

I had the flat slides on my 83 GS... CLACK ,CLACK ,CLACK ,CLACK CLACK!!!! ONLY TWO POSITIONS ....off and ON!!!!!

i know you had mentioned the webcam 505 cams here, and also on some forum posts. what options are available today for 1.6s? i know that options are extremely limited. such as not being able to find high compression heads, and what seems to me is a lack of info in general about n/a builds especially on a 1.6. would a stand-alone ecu, free flowing exhaust, passenger side intake, and possibly some head work(porting, polishing, possibly decking) work as a start to an n/a build?

Wht you can suggest for mazda familia 1.3cc carburator replacement?

Any possibility of having itb's for the nd miata? Bbr gti has a kit for the nc.

can the itb give more hp with stock injectors?? or we must change them for sure??

How would itbs on a vvt motor from the nb2 work? Would that make a difference?

Do an ITB kit for the NC and I will buy it.

If some is interested in getting itb's for the nd1-2 let me know!!! I found 2 manufacturers that are willing to make them.

could you drop the name of the shape you spoke of at 34:08

The red wires can be combined with the stock ecu or only with an aftermarket???

fun fact: i have desinged an adapterkit to mount the e39m5 itb to the bp4w and vvt engine :D

Is that a E39 M5 I se in the backround?

Anyone interested checkout Ethan Vermillion he is working on a 3d printed adapter to run bike throttles. Nothing wild but all the retro noise with a slight increase in power. I'm planning to work on something myself as well- but I believe he plans to actually market his setup

Probably way too much work and I don't have an aftermarket ecu to look at;possible to use a barometer on an aux line to see the air pressure with the tps and use the two combined to make the map a little more accurate and reliable? Like I said maybe way too much work for an issue only a handful of people would have. The math doesn't seem too terrible to me but I honestly have a 3 RU-vid video degree of knowledge on tuning.

"Professor Batshit" LOL!!

Motorcycles have ITBs .

who else want itb on nd

WHO IS BUILDING A FREEVALVE HEAD FOR A MIATA????? are we talking the Koenigsegg Freevalve thing? or something else?

What about Mikuni Flat slides ? 48 mill

I take it that you definitely have to lower the fuel pressure To what ? Time to change my Hydra settings ? URGHHH!!!!