NC MX5 Miata: Are Individual Throttle Bodies Worth It?

The NC Miata with the Duratec 2.0 motor is an absolute joy to drive, tune and modify. With the top down the sound of ITBs is absolutely intoxicating. We all know that. The question that we must answer is: How Much Power do ITBs add?
Thankfully we have Stanley’s car on our dyno to tune and dial in his BBR225 ITBs the Stratified way. So let’s see if these give you more than style points and eargasms.
Enjoy!
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MX5 Miata Tuning
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Enjoy!
0:00 Intro
3:38 Dyno & Tune
4:24 Results
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#Miata #MX5 #NCMiata #ITBs #stratifiedtuned #stratifiedauto

[@WoodEe-zq6qv]

ITBs don't make power, they make music.

[@stratifiedauto]

Powerful music!

[@EmperorSheepy]

What a sound ❤️

[@alejoYVR]

Sounds great, looks great!

[@stratifiedauto]

Drives great too!

[@chaoticpuppet1]

That's neat. Like the originality. There's a company that also does superchargers. I think it's vr racing.

[@fernandogutierrez8357]

I used to had an NC. Header 4-1, decatted only a muffler mounted. Adjustable dampers front and rear. Light wheels and sticky tires. God, what an incredible machine. I could not mount the ITB's cause I sold it. But I'd like to have another one.

[@stratifiedauto]

Yup, I had a supercharged one as well. They are a tonne of fun!

[@smiles564]

I love those red door cards

[@stratifiedauto]

This was a special addition.

[@turbo32coupe]

i run 8 ITBs on a 452 cu.in. Ford FE. I use a Megasquirt 2 in ITB mode. ITB mode is a blend between Alpha-N and SD. It's very hard to tune ITBs in solely Alpha-N or SD. both have compromises. Typically, ITBs produce more torque than a single plane because of the ram effect. Usually the trumpets are too short to produce a tuned intake effect. The don't always make more HP. A well tuned single plane will make similar horsepower, but the part throttle function idle, and throttle response is a world of difference.

[@stratifiedauto]

I agree and we did not have this exact car to test against. However the throttle response is undeniable.

[@jandsmx5]

Hi, great video, thanks for posting. Can you please let us know what those peak numbers for BHP and TORQUE were?

[@stratifiedauto]

Our dyno measures wheel hp and the itbs produced 181whp and non itb 161whp on our dyno.

[@ChurchAutoTest]

Cool stuff. Question. How do intake temps look on the road with the hood closed vs. the stock manifold and a typical intake? ITBs always look awesome on the dyno but without cold air ducting sometimes road performance can take a hit.

[@stratifiedauto]

The air temp sensor is still on the OEM air box. Based on the fuel trims the air temperatures are stable and fairly accurate unless sitting at a stop light when you get some heat soak.

[@altoticket]

Properly sized (long tubes) ITBs + Lightweight Flywheel is the way to go

[@stratifiedauto]

Agree!

[@SoylentGamer]

Throttle response is a big part of ITBs too. The air doesn't need to take as long to reach your engine. Yeah it moves at the speed of sound, but that's still milliseconds.

[@stratifiedauto]

Throttle response is indeed very good.

[@yOnKiNaToR]

Did you have issues with idle tuning? My ITB setup on ECUTEK runs horribly on the initial warmup phase and it seems to die when the AC compressor runs or when i put load on the power steering pump.

[@stratifiedauto]

Did not. It could be a tune issue or an air leak or imbalance in the throttles.

[@143CAR]

Silent night background music? HAHA

[@shonsweet2781]

Air intake not getting cold air when hood is closed. I see issues later on with it.

[@stratifiedauto]

Tested this with car moving and only saw issues when stationary for longer periods of time. You could cut in some intake NACA ducts into the hood.

[@simoneamodei9265]

Power increase depends on runner geometry and not where you place the butterfly. I think it's easy to understand that when you floor the pedal the flow is parallel to he butterfly so that's like no butterfly being there. You even have less restriction with a well designed single throttle (less pumping losses). The only reason of ITBs is throttle response because less volume to fill on transient throttle (noticeable only at low rpm let's be honest) and more sound with open trumpets (not good for power apart from rare extreme NA setups). Remember itbs were used in racing only to make the car more driveable with extreme cam durations not to increase top end power.

[@stratifiedauto]

Can we conclude based on the dyno data that the OEM manifold then poses more of a restriction? The odd part is that it makes power across most of the power band. If it flows better you would see more top end but the offset is across the board. Low end is often helped by velocity.

[@socleanmx6]

P​@@stratifiedauto

[@turbo32coupe]

You are exactly correct. I run 8 ITBs on a 452 cu. in Ford FE with a very large cam. It idles at 600 rpm and has great throttle response.

[@bombardierboerboels]

Does it not need a cam for best results from itb

[@stratifiedauto]

A cam will shift the power band to the right. So it will make more top end at the expense of some bottom end.

[@MR-06]

Stratified do you think you’ll ever swap a 2.5 Fusion engine in a Miata & offer tuning for turbocharged 2.5?

[@stratifiedauto]

We may do this swap on our car. We can definitely tune the 2.5 now if you have this setup.

[@just.a.simplejoe]

Do you guys actually tune ND1 or ND2 miatas?

[@stratifiedauto]

Yes the ones that are supported by the Ecutek software.

[@semisolutions]

Does ecutek support alphaN?

[@stratifiedauto]

Yes. This is how I tuned this car.

[@ThatHondaChannel]

Isn't it better, and I mean much better to tune ITBs via TPS than off a MAP sensor. Serious question.

[@stratifiedauto]

This is tuned via alpha n which is using TPS as the load variable.

[@MrTAKIS1984]

Itb kit for 1.6 nb2??

[@stratifiedauto]

Would love to tune it

[@krusher74]

sounded like a terrible bog when you were bilping the throttle at the end. The air flow isn't linear you need to tube for e that big jump in CFM as the throttle starts to open, this may be your loss of TQ on the dyno graph.

[@stratifiedauto]

Once you get past that very low rpm resounds very well.

[@Bonsai-Miata2020]

Seems like a lot of work for little gains when the ND2 starts at 148 hp to the ground

[@stratifiedauto]

The nd is a great platform. As is the nc. It’s not just about the power in these cars.

[@LolloG_15]

the 2.0 have vvt?

[@stratifiedauto]

On the intake cam

[@FairladyS130]

How about a bigger throttle body on the stock manifold which is obviously designed for all round performance. This setup is really high rev race car spec, if more useable power is required for the street then put a bigger engine in it.

[@stratifiedauto]

Have a look at the dyno sheet in the video. It makes good power down low as well.

[@P71ScrewHead]

Positive displacement superchargers ae the best for the street n track.. But yes, no replacement for displacement, ever..

[@FPSRepair]

What's the point of dynoing with the hood up on a system that will be sucking 70°C under-hood air when it's down? I mean, it's not even close to a real representation of what the car will see on the road. Are we interested in throwing up a dyno number, or are we interested in seeing what happens during actual use?

[@RotormanMTB]

I was thinking the very same thing. Under bonnet heat soak temps will rob it of power... that's the real world scenario. It does sound awesome though.

[@stratifiedauto]

The fans in the dyno room do not accurately reflect airflow while the car is moving either. After the dyno session we took the car out on the road for testing and watched feedback O2 and air temperatures. The only area where it starts to heatsoak is when sitting idling such as at a stoplight.

[@gianniszafranas2037]

What wheels are this?

[@smiles564]

Those, what wheels are those

[@gianniszafranas2037]

@@smiles564 what

[@BB-wz6bx]

@@gianniszafranas2037 Quite sure they are OZ Leggeras

[@grecoconduris6716]

Silent Night playing?

[@louisbabycos106]

Very complicated set up . Why not a turbo or a supercharger as it comparativly simpler .

[@stratifiedauto]

It’s not the most power per $ but the response and sound are excellent. It’s pure NA.

[@krisholt8390]

Nothing quite like running down the road investing hot air just to hear the engine music.

[@stratifiedauto]

Hot sir ingestion is not too bad when moving.

[@krisholt8390]

Sorta make sense, so more for road racing than autocross.

[@yOnKiNaToR]

I run a plenum box mounted to the stock airbox and i can tell you there is a large difference in IATs when running just an air filter. I just don't get the sound anymore.

[@808touge]

Christmas music lol someone is getting fired

[@Jayda08]

Once the hood is closed, engine is sucking in hot air. 🤦‍♂

[@stratifiedauto]

When moving it’s not too bad.

[@jasontate3365]

Wow, everything here is wrong. ITB filter is sucking in under hood air, which is bad. Dyno run is with the hood up. Unless the car is driven that way normally, might as well have just drawn the graph with a crayon. Where’s the big fan blowing air into the grille, simulating actual operation? With ITBs, you’re giving up the ram charging effect in a normal intake manifold. Dyno run is just a WOT run up to redline, so you have 4 WOTs. Is that better than just one TB? Need part throttle runs to show if this is actually usable, or just a Dyno queen. Speed density programming? That’s just a smart carburetor. I’m not bashing, but sometimes you just need to tell the customer that what they want is worse than what they had. As far as Dyno runs go, check out Banks Power for a tutorial on how to dyno anything for accurate, real world results.

[@stratifiedauto]

Some valid points. Speed density tuning is common in modern vehicles - yes OEM ones. Without a manifold it is necessary here. I did testing on the road and you can see how things change air density wise via the feedback of the o2 sensor. The only time you start to have an issue is when you are sitting and idling. The OEM intake is also not ram air. It has a snorkel but not ram air. Finally transient response is excellent. This was thoroughly tested and dialed in both on the loaded dyno and on the road.

[@turbo32coupe]

You are exactly correct in all your points. Part throttle and low rpm are where the ITBs shine. Ideally, ITBs should run a blend between Alpha-N and SD. Megasquirts have and ITB mode that blends these two functions.

[@P71ScrewHead]

@@stratifiedauto i think a hood scoop would be good for it now..