🛠 Can ITBs increase horsepower? | TECH TUESDAY

[@haltech]

It's Tech Tuesday time! Stacks look great and sound awesome, but the effectiveness of Individual Throttle Bodies is a hotly debated topic. And today we'll throw some gasoline into that fire by offering our take on the subject. ..... Haltech Knowledge Base: support.haltech.com/portal/en/kb/haltech Need help with your Haltech products? Contact our Tech Support at [e-mail] ----------------------------------------------------------- Liked this video? Here are more like it: Fuel Pressure Explained: kzbin.info/www/bejne/iaO0pIRnqrlmZ8U Why some cylinders run hotter than others: kzbin.info/www/bejne/i6HTlJ-Fhs-ma6c Throttle Pump Explained: kzbin.info/www/bejne/en63ap6MhJyZi7c

[@carguynewb7856]

Tbh would be happy with a stock engine with itb's I don't care about it not having power because the sound makes driving more enjoyable

[@negativeindustrial]

ITBs are like exhaust mods. Yeah, you can gain a few HP if you do an exceptional job at it but, let’s be real, you did it for the sound (And it was probably worth it)

[@Jay-yg7fp]

i just wanna cool car with some coilovers and pushing 300hp max. are getting a itbs good idea for a daily?

[@negativeindustrial]

@@Jay-yg7fp Not at all. ITBs are for people very committed to having ITBs. It’s difficult to get a decent vacuum reference for the other various parts a daily driver needs to be civilized day to day.

[@Jay-yg7fp]

@@negativeindustrial so getting a proper single throttle body with a good NA set up better?

[@negativeindustrial]

@@Jay-yg7fp If you want to keep it simple and reliable. You can build something more wild when you get a second car.

[@warrior29363]

​@@Jay-yg7fpyes

[@Reventon777]

The biggest upside of ITB's is the ability to run a hotter cam with more overlap.

[@rattyratstuff7125]

4age origionally had itbs. it sounds even more insane with stock intake for smog XD

[@turbo32coupe]

You are correct. I run a 8 ITB setup on a 452 cu. in. FE Ford with a hot cam, and it idles like a stock engine. The cam is a 248/245 on a 110 LCA and acts like about 225/225

[@midnightzero2173]

Yep. My E30 325i engine had a big cam, sounding lump as hell. Switched nothing else but my intake to ITBs, made no power and no torque gains, but I lost the loping sound. The engine was already bottlenecked by it's compression, so my intake wasn't limiting it and as such the ITBs netted me no gain. When I went to a high comp, stroker build, the stock intake would have limited it however and with my much larger 288 cam, the ITBs made it a much more manageable street engine.

[@repingers9777]

​@@turbo32coupeI just realized Honda VTEC engines have bigger cams stock than what aftermarket cam sizes are for other engines and cars lmao😂 I think the 200hp k20's have 260 duration exhuast and intake cams on the high cam and 220 on the low. That's why they are so loud and make power at 8000rpm I guess. I noticed with high revving small engines itbs give benefits so there must be other limiting factors and tuning issues for other cars

[@dennisrobinson8008]

​@@turbo32coupesweet

[@PepperSnek]

I think you didn't stress enough how beautiful the throttle response is on a well tuned ITB setup. There's nothing quite like it.

[@eliasdanks4352]

Granted the lfa has titanium and titanium alloy internals, but it revs to 9k in .6 seconds with its itbs

[@murty4471]

Tuning tricks for an ITB setup that uses TPS vs RPM would be a great tech video.

[@jarrodflood1353]

I believe high performance academy has a very detailed video on that topic

[@UngluckInc]

@@jarrodflood1353 yup, use AlphaN

[@kasuraga]

@@UngluckInc yeah, alphaN tends to be the way to go with ITB's, but I've seen people make vacuum reservoirs to run speed density. Was planning on doing that on my honda but life got in the way. Still have the components, just not the tools or money to finish the project (engine is cooked too now)

[@clutchboi4038]

@@kasuraga hell Yea because then you could use a turbo because alpha-n is no good for boost. Get back into your project bro you can do it. My project been sitting years and I'm finally getting back into it and not letting life and my dumb feelings stop me this time.

[@nobodynoone2500]

Using a vacuum balancing line, or individual sensors with an ITB interpolation device or software are the better way than guessing with rpm/tb.

[@ricepony33]

Garage 4AGE channel tests ever ITB setup imaginable

[@Codeman785]

Well what's the consensus?

[@zac2384]

@@Codeman785 if i remember, they're better when they're the right length.

[@The_One_Over_There]

ITBs are indeed one of the most stunning things one can see under a hood (in my honest opinion) And they make some engines sound really amazing, Like the 4AGE engines.

[@biggboysouth]

One tip I would like to share on helping to stabilize vacuum readings (at least on naturally aspirated cars, I have not done this on a boosted car) is the use of a vacuum block and some one way check valves on some (NOT ALL) of the vacuum lines. In my limited experience the check valves have helped in two noticeable ways. First it allows for lower and more stable idle vacuum readings and secondly by controlling which and how many lines are allowed to release vacuum you then can better control the speed and behavior of the vacuum loss. I data logged my cars stock plenum vacuum reading before switching to ITBs. I then set up my vacuum block with check valves and data logged and played with different configurations until I found one that gave me reading as similar to stock as I could achieve. Once I figured that out the car became much nicer to drive and tune. I'm already anticipating some hate coming my way as I shared this same info in the MIata ITB facebook group a while back and it seemed to confuse or enrage people for some reason. I do not claim to be an expert just wanting to share my good results on my particular application.

[@RyuMoto]

Would love to see an ITB tuning video. As EVs take over I suspect such things as ITBs will be more popular as it enhances the drama of an ICE.

[@copperlocks1]

There are a few ways to do it; the old way was is to connect Vacuum gauges to each ITB , (so 4 gauges for a 4 ITB setup)..adjust idle screw on the first one to get highest vacuum reading ..then match the other 3 to the same reading; a manometer setup is more accurate. the second way is to use a syncrometer . this measures airflow but adjustments are made at the linkages to match airflow..to each TB ( this is not universal) kzbin.info/www/bejne/b2PFkKqZa9llms0 kzbin.info/www/bejne/j5S4qXyietZ7qpI

[@hoonaticbloggs5402]

The best use for ITB is when using a big cam , they vastly improve idle and low speed running with lots of valve overlap. I have them on an LS1 with Haltech

[@georgegavrylenko1031]

Care to share details and maps by any chance?:)

[@hoonaticbloggs5402]

@@georgegavrylenko1031 Unless you have an ls1 with the exact same cam and itb set up I don’t think my map will be of use to you

[@georgegavrylenko1031]

@@hoonaticbloggs5402 basically just out of curiosity. But some starting point wouldn't hurt. I'm having ls454 cam with 1.8 rocker ratio, itbs and ported 243 heads.

[@kasuraga]

Do you know why that is? is it due to the lack of a plenum between the valves and the throttles? It seems like that would be the case since you'd have more of a chance of flow reversion with high overlap and a normal plenum intake, vs the short distance between the throttle and valve with itbs. It would seem like it would have less volume to reverse into during idle and part throttle. at wide open throttle, the incoming air would have the velocity needed to prevent any sort of reversion. I don't know if that's the case, i'm just trying to go by how I think the pressure waves would flow in and out of the engine during the overlap.

[@TomSmith-cv8hk]

@@kasuraga You'd think that's the case, less exhaust dilution in the inlet at high vacuum because the other intaking cylinders aren't pulling on the cylinder in overlap resulting in less misfires.

[@jooba67]

Wow, that was the best explanation of itb's ive ever seen. Learnt heaps. Thanks for your time.

[@stopspin]

It's more for intial responsiveness for na cars even though it can increase lil in power but more for responsiveness. Great setup for Gymkana events or time trial precision courses or short race track courses where high hp cars suffer from turbo lag.

[@stevesedio1656]

I agree. The biggest advantage is throttle response. A plenum slows the change in air pressure in the cylinder, the bigger the plenum, the slower the change.

[@esnevip]

The twin DHLA 40's were the best mod of all for me, the music, the snappy response and fairly substantial bump in torque.

[@racketman2u]

They were a great carb, I got better results from them than Webers or Mikunis on my 240Z. I wonder if throttle response is as good on ITB injection as the "pre-emptive" accelerator pumps on the Dellortos and Webers?

[@caryoga3211]

It would be great to see a “how to set up alpha n tuning for ITBs” video. I’d love to confirm if I’m doing it right on my 4age 20v

[@sepg5084]

ITBs for looks only? Nah. GT3, F1, etc. race cars use them, i doubt it is for looks 😉 ITBs on race cars have plenums too, but the velocity stacks are inside the plenums. A lot of motorcycles have ITBs, whether FI or Carb. Motorcycle tuners deal with them on the regular.

[@John.strong]

I recommend dbw with itbs Think about it You can tune how far the throttle opens to the pedal that can change the ratio and make it far more drive able Also change how fast the throttle opens making it more accurate on a standard VE table I've successfully tuned an itb setup with dbw like this and it drove really well and actually made more power because you can limit the throttle opening vs engine speed making the air speed more appropriate for the air consumption

[@donguhl2499]

Most modern 600cc and 1000cc supersport bikes are dbw itb systems. And several of them have variable length velocity stack systems. They are very cool!

[@rachelpurity1]

Only works if you don't have a straight cable pulley to the throttle, like on most pre 2000s cars and even some legends from during the early 2000s. Also should make throttle response a little less direct, no?

[@ulisesavila2879]

​@@rachelpurity1 no, because a dbw tuned for performance will open the throttle faster than you could do it by cable. It is just that all people had bad experiences with dbw systems tuned for emissions and starts to diss at dbw systems. A sensor will always react faster and better than we could do.

[@rachelpurity1]

@@ulisesavila2879 It is literally physically impossible to have a more direct response than with a straight physical connection, so the "opens the throttle faster than you could" is complete bullshit. But let's assume it just opened the throttle faster than I could put my foot down... What good does that do? The gas pedal is not an on off switch. The entire thing is not as well suited for actually driving. It also has no direct feedback, which sucka.

[@ulisesavila2879]

@@rachelpurity1 do you really read and respond to things do you understand? I only told a that a properly dbw system for performance will outperform a cable based one and you are making it sound like a dbw will work so fast that you cannot drive smoothly which is incorrect. Not only that, just telling it is completely bs just because there is not direct connection is like telling that a good autobox is still slower than a manual one. But do whatever you like it is your car and enjoy the feedback of "I need to clean my system, the cable is not smooth as always"

[@Tapped-o9k]

ITC is way better imo. Individual turbo charger. 1 turbo per zylinder, one exhaust per cylinder. Beautiful

[@HimWitDaHair98]

Let's not lie to ourselves, it's mostly for the noise

[@BWtheHD]

Sorry mates, I don't mean to highjack your efforts here, it just came out of my head when it comes with the topic of ITBs. I thought It would be a nice combo from both concepts and hands on perspectives. So There's a channel called" Garage 4age", he had done a lot of dyno pulls with different runner length and/ or velocity stacks in a given engine and got some interesting results a side from some equations I found on my self-learning journey.

[@tomafh]

I'm about to tackle this exact situation...luckily I'm coming from dual Weber DCOEs. Overall intake runner length from the intake valve to the end of the velocity stack is paramount. I've been able to tune to the 3rd and 4th harmonic already. I'm looking forward to challenge. I'll be running Jenvey Heritage with an Elite 1500. I've already got a vacuum log to go in as well. Will the fuel trims/self learning work well or at all in this style setup?

[@johnjones928]

Just like in the old carburetor days all the tuning in the world won't save you if you pick the wrong size ITB, and things are even worse with the smaller displacement, higher reving engines of today. Too small: great throttle response with a choked top end. Too big: sluggish throttle with a top end rush. Finding a setup that allows good low AND high rpm performance means your not going to get the absolute best out of either but it's probably the best compromise for the street. Motorcycles have handled this by adapting variable length intake trumpets and highly sensitive ignition mappings, but their relatively high power to weight ration means they still have good alacrity even with less than idea tunings.

[@DonnyTrent5533]

Until you've driven an itb car, you have no idea what throttle response feels like.

[@yudaresigama4209]

Totally agree with this, but tuning an ITB n/a engine is so much fun! (Eventhough 95 percent of tuning is spent on idling and part throttle)

[@H3avyHaul3r]

kids… just imagine tuning a set of some 45mm weber dcoe carbs with jets…look’em up

[@bvward]

What about Dell' Orto's? ;)

[@jan_phd]

I have 6 throttle bodies on my car, and built servo control onto each, so I could tune remotely. And yes, each has a metal 3D printed plenum. Looks nice.

[@daanyl]

sounds very intresting servo control on each throttle body, do you have any specs and pics you can share? i am researching and starting my design at the moment for my honda k20. did you print it in carbon fiber nylon?

[@BadEngineering]

Went from 55hp to 85hp with nothing but ITBs, although the stock SPi system was very ancient compared to the more modern ITBs and standalone! Next is head and cam for more!

[@otm646]

If you had a 40% of your horsepower locked up in your original throttle body setup you had other serious substantial engineering failures with how that motor was previously configured.

[@BadEngineering]

@@otm646 ask that to VW... Its very common to see 50%+ gains by fitting bike carbs on stock ignition, let alone ITBs and standalone management.

[@zestydbd6830]

That's crazy!

[@rhetericalpha]

Awwww yes ITB. The joys of tuning a motorcycle on an after market ECU. TPS vs RPM. And second fuel table to compensate for boost. Lets not forget target lambda tables for both tps and boost tables. Good video

[@warrior29363]

I am removing the itb of my swift twincam gti car. It is a real. nightmare in lower rpms to work correctly with the ecu. I am a good pilot so I will not need those little extras hp for a race.

[@L3xou97]

My motorbike has both 😎 Cause it has only one cylinder lmao

[@IntegraDIY]

ITBs are best at WOT, and can suffer from low to mid range RPM. Where as a single TB with a IM makes optimal power throughout the rev range but can suffer at very high RPM.

[@gordowg1wg145]

ITBs are kinda like tubular exhaust manifolds - get it right and they can be rather helpful with engine' cylinder filling and give a bump in power/torque where it's desired - but get it wrong and it can hurt it.

[@johntaylor1947]

I had three two barrel Webbers on a six cylinder Datson Z car with velocity stacks, cam and Heder to mach. It was a fun wild car that sounded like a formula one beast. The only drawback was a loss of torque at low RPM and it begged to hall ass.

[@just.a.simplejoe]

Woah...... literally one of the most professional and informative vid on ITB's. Could be a great one to save for those needing a crash course on this. Great job!

[@darkmugetsu6572]

My Honda Beat has MTREC or Multi Throttle Response Engine Control. 3 throttle bodies for 3 656cc cylinders. The horse power of the MTREC E07A engines are upped from the 49 hp engines used in Honda ACTY's to 61 hp and the red line is bumped another 2000 rpm higher.

[@DjO_89]

Was planning on taking the beat's itbs and putting it on to my acty truck lol

[@N0ENEMIES]

They also sound amazing

[@paial]

Garage 4age, ITBs tested on the Dyno for days...

[@The_R-n-I_Guy]

I've wondered about putting a homemade tube plenum and individual single barrel carburetors on an old inline 6. No computers or sensors. How well do you think that would work? I know it would take forever to tune. But would it work good enough to make it worth the effort?

[@JustinPaul1st]

Think Alfa side draughts same principle

[@SuperiorEtchworx]

It does work but they are a pain to tune. 2 barrel side draft webers or dellortos are much easier to synchronise and tune than single barrel setups.

[@ProtonFilms_Mark]

Those trumpets just look sick, I think I want them just for that reason alone.

[@SJR_Media_Group]

It comes down to VE (volumetric efficiency). On a NA (normally aspirated) engine there are some losses in airflow and having 100 percent is rare on a production street car. Good race engines can actually have a VE over 100 percent because of tuned intakes and exhaust. Today, many cars are turbocharged. VE can be 200 percent (2 times NA). Some numbers to consider... at 6,000 rpm the pistons are going up and down 100 times per second. On a 4 stroke engine, the intakes are opening and closing 50 times per second. That's not much time for intake valve to stay open. No air can enter if valve is closed at wrong time.

[@petercunningham3469]

from my experience with stack injection on small blocks with alcohol we generally run the engines to 6500 8200 pretty small window to ram tune in that said Ram length definitely makes big swings if you get off too far newer manifolds have long runners but short tubes, visa versa for street itb interesting to overlap dyno curves look in comparison in each instance. Great presentation too Thanks for your insights🙂

[@seanb250]

The one thing I personally think is missing in this video is the other side of the ITB size, going too small. Unlike a common plenum where a single large TB is only supporting a couple of cylinders at a time, not all 4/6/8 or whatever, an ITB has to be large enough to support the cfm demand of that cylinder and intake runner by itself. Take a 45mm ITB for example, it only has enough area taking into account the shaft running through the centre to support an intake port of 300cfm max. This is all at 28” water test pressure. Yet a single 80mm TB could support 1030cfm, that is more than 330cfm for 3 cylinders all at once which doesn’t happen. So the ITB size has to be big enough even for a mild engine, even stock LS3 heads flow 300+cfm so 45mm itb’s would choke them.

[@Rkenshin00]

this was actually incredibly well put and helped my understanding a lot. i love the unbiased approach with points for cool factor

[@donovanlucibello379]

Great explanation, Mate. Cheers from USA

[@wakjob961]

For mostly High RPM WOT track style driving... ITB's. Street or daily driving is a different story.

[@233kosta]

My bike has these. I think they did that mostly for packaging reasons, but I'm sure it adds to the soundtrack as well

[@rachelpurity1]

ITBs are somewhat to an NA engine what a Monster can sized exhaust system is to a turbo build. They are a last sorta upgrade after the engine is already pretty built up and at that point they really give it a kick. On a first gen Miata for example I've personally witnessed them kicking up horsepower from 150 to around 165 on an already built engine. The biggest upsides of ITBs over single are - Insane throttle response (this is what makes them popular in the Japanese and European drifting scene) - Gnarly sound and - every cylinder getting its air as it needs it, no choking the last cylinder or something like that. The modern approach to ITBs, especially in Europe, often includes an airbox around the velocity stacks, connected via giant hose to a dedicated intercooler and intake setup, to feed the engine clean, non turbulent and really dense because cool air. Gives them an edge over the typical style abroad.

[@JohnDoe-mx1sq]

A free flowing exhaust is the first thing you should do on a turbo engine. Starting at the turbine outlet.

[@elektro3000]

Great explanation of how ITBs work but I don't think you were very clear about air volume flow rate (horsepower capacity) versus the air column length between the throttle plate and intake valve (throttle response). If your single (or multiple) throttle body setup cannot flow enough air at high RPM and pulls vacuum at WOT, you could install ITBs...or just install a plenum that accepts a larger single throttle body (or two throttle bodies). However, ITBs do something different that plenums can never do at any size: Reduce the response time between changing throttle position and changing engine torque output. That's why correctly tuned ITB setups don't just sound snappy, they FEEL snappy. Floor the throttle pedal, and the engine delivers torque sooner.

[@MRtucnakCZE]

Always happy to see new vid! Question: Variable intake runners - does ESP support them? Suggestion: What so special about some VAG engine?

[@tonyanderson4774]

ITB’s are somewhat of a saviour for those of us trying to extract big power out of dinosaur engines like the Ford Crossflow 6. I recently purchased a Haltec 2500 and all the accompanying sensors for this very reason. Whilst the Aussiespeed manifold is a great common plenum manifold, it has it limitations, especially on alky fuels. I’m looking forward to even cylinder fill that comes from ITB’s and yes there are downsides if done poorly, but that’s the same as a poor common plenum setup. Anyway, time will tell, as will before and after dyno figures and ET/MPH. I’ll let you know how the JENVEY ITB’s and Haltec go. Cheers.

[@rodneyberry531]

Agree. Idle stability, ability to cam how you want, throttle response, minimal pumping losses and equal cylinder fill/VE. If that last one is not equal between cylinders, some cylinders will effectively running different mixtures and trouble can ensue. Also expect uneven ring wear between cylinders. Plenums will work, but most flow is shoved to the rear cylinders with inertia. Love the old crossflows.

[@zuzuzaza98]

The snappy response is why itb used in almost every motorcycle and NA race engine. With itb you can get out of a corner quicker.

[@joshuayammer1994]

Vtec engines love ITB’s. Both powerbands benefit from them

[@WarriorsPhoto]

A lot of good information and there's nothing like an ITB SET UP! Have you started tuning your ITB set up?

[@RolanTHUNDER]

I have a Toyota Corolla AE111 GT that has the legendary 4AGE Blacktop 20 Valve engine with ITB's as stock. Even stock it feels great and gives the impression that it wants to be at WOT all the time - that's a cool quirk of ITB's I think people need to know ;) I'm about to order SQ engineering 100mm velocity stacks and can't wait to swap them in place of the stock rubber ones. Maybe I'll tune it on Haltech Elite 750 from BGRS ;)

[@gabeshaw3721]

My 2000 Honda CBR 600 had individual throttle bodies, velocity stacks, and 4 carbs.

[@MarcosCruz-xe7vv]

That's a pretty cool t-shirt.

[@PrayItForwardAGAPE]

Hey a very practical and fascinating use of these principles was utilized by Yamaha in the first 2 Gens of the Ford Taurus SHO. They use Butterflies to open Short runners into "ITB's". While at lower RPM it uses the longer runners. In functionality it is very similar to Vtec. The result is a gorgeous center piece under the hood reminiscent of the Busso in appearance but much more interesting. I know from experience tuning the exhaust after bigger MAF TB and Big Bore Butterflies these engines sound like Honda and Ferrari had a love child. Ringing it up past 7 and its a unique experience to say the least. I would love to see what a Haltech could do to after all the tried and true first and second Gen mods.

[@a_Fax_Machine]

So I'd be better off running a Holley Sniper 2300 on my Ford Lima 2.3L than cobbling together an ITB set up? Thats what i get from this

[@aussiebloke609]

I suspect the difference in performance was a lot larger back in the day, what with siamesed ports and log-style intake manifolds on small engines and such. Multi carb setups were first, and all the rage for straightening out the manifold as well as getting better response, what with pumping losses made such an impact on performance - and it was all the more noticeable when a quick car made only 100 peak hp or so. I remember ITBs were definitely the rarity back then, generally only found on serious race efforts (and even then, a set of DCOE Webers was just as likely to be found.)

[@lasskinn474]

yeah how much of a difference such a mod can make really depends on how good the stock intake was in the first place. say a 2 liter that's doing 100hp stock vs. a 2 liter doing ~150 stock. if the stock manifold/runners are rather good already it's not going to be an easy gain.

[@HalferLandPerformance]

We (HalferLand Performance) run a dual 68mm throttle body setup and saw positive maps pressure at WOT (basically boost) even when we were NA. I would recommend a DTB setup over ITB's (tuning is a PITA, especially daily or street setups). Now with the same DTB setup we are making 550whp on just 8psi of boost in our Turboed J35a7 Swapped 06' Accord Coupe 6mt

[@racketman2u]

Why would shared throttle bodies ever be superior to ITB? doesn't make sense, all other things being equal

[@brentvalentine]

I guess I'm an old school racer, I kept thinking about carburetors and fuel distribution. eg: 3x2bbl and dual 4bbl. Fuel injection doesn't really have as much of an issue. Great explanation of velocity, airflow and the 'bounce' of the air in the plenum. I didn't think it would be as much of a issue with injected engines. Fluid dynamics still plays a part...

[@233kosta]

Fluid dynamics *always* plays a part 😈

[@KeatonsCarlott]

I HAVE JENVEY ITB FOR SALE. UNUSED. NEEDS A HOME. ID love to find a new owner in the u.s.

[@nobodynoone2500]

ITB's are for throttle response over peak power. And the glorious intake noise. But more moving parts and tuning issues make it rare. A good tune shouldn't loose much, but it is harder, mostly due to vacuum/maf/map sensor complication, but recent advances have been made. Most throttle bodies these days are oversized, particularly aftermarket, decreasing intake velocity, losing power in naturally aspirated engines.

[@TheNivekvideos]

When tuning (4 Cylinder example) you have 4 engines to tune, not just one, if you have individual Fuel & Spark Trim with diagnostics per exhaust/cylinder, you can get every hp out of the engine, the same is not true for a Manifold based engine. Air Disturbances & Imbalances inside a plenum based on who designed manifold can be small or great........

[@jonathanlich5670]

The alfa 33 1.7 16v has a switch in the itb's for idle. One map to idle somewhat good. And a maf at the begining in the maniifold

[@micksmith3021]

And they sound so good on a Na setup.. Like some good old Webber 45 mm dcoe carbs.. A heavenly sound in the forest

[@liamlindsay1458]

Id like to know what power gains you can get on a stock bottom end built head k24 block k20 head Frankenstein with itb’s as compared to a single intake plenum

[@warrior29363]

I had a Cultus gti with itbs, it had 139 hp. It was extremely hard to tune and to keep reallability. I put a new gearbox and good intake, now i have 135hp that never fails... Itbs suckks,👎

[@bansheemopar]

Generally a great video, but I think you got one importatnt thing quite wrong. The size of the throttleblade is in an ITB setup extremely critical to the maximum horsepower every cylinder can produce, and therefor you will mostly make it a lot worse when switching form a common plenum to an ITB. Simple reason for that is, that the plenum volume and the fact that the cylinders alternate when they need air, a single throttlebody will almost never be a noticeable restriction. And the fever Cylinders an engine has, the worse it gets for the ITB. In a V8 engine, the air needed from the total engine is almost a constant, because the curve showing the amount of air needed per crank angle has its high point in the middle 90° of the intake stroke, and because a V8 has a firing angle fo 90° the increasing and decreasing demands of air per cylinder match each other really well. With an ITB, 7 of the 8 throttle bodies are doing nothing, while one has to cope with almost the same air demand as the single throttlebody of the common plenum, and that without the plenum to soften the blow. I would always go with a slightly bigger sinlge throttlebody, than trying to get ITBs to manage the air demand. My Truck has a modifies LS1 in it, that produces about 400-430HP at the crank, and does so with the OEM truck intake and 78mm throttle body without pulling vacuum at peak HP. To get ITBs to support 80-85HP / cylinder, would need about 50mm per cylinder. At the point the 78mm common plenum runs out of steam, more like 60mm.

[@Dominik189]

You dont do ITB's for the horse power gains, you do them for throttle response. Pair ITB's with a lighter flywheel, a better exhaust and decent suspension. You'll get a fun car for a modest budget.

[@connor45rm85]

All true BUT a seriously oversimplified explanation, itbs with the correct runner length (inc stack) and a cold air intake (airbox) will produce the high rpm benefits of an open stack with 7-10% better mid range torque. Most (non race) itbs have serious deficiencies in their design and setup, hence why many people have little gains.

[@JagoTFC]

The size of the runner is in relation of the cylinder shape and volume? Like a 83x60 bore and stroke would have a runner 60mm tall and 83 in diameter?

[@programmerdvorak7032]

no, we don't run itbs for more power, we run them because a good condition carb for a 70s I4 car is a bad purchace for longevity, a new or almost new carb costs an arm and a leg and most likely needs a reworked header or new header a row of 4 bike carbs can be had for at least 1/3rd of a used original carb, I can find cbr600 carbs for $100 and $150 and they have parts available and people to work on.

[@m.yankov8780]

Can anyone recommend a good ITB kit for the 4g63 16v 150hp variant found in the Gen 1 eclipse? Thanks!

[@mpetersen6]

If it is solely based on looks. Nothing looks cooler than one Weber side draft for every two cylinders. Now there are EFI units built to look just like Webers. Another factor is runner length. Tor qs US at lower RPMs or more HP up top?

[@Kodaoda]

I set up a Porsche with itbs on a Haltech 750, tried emailing my file to you guys but never heard back from support. Got it running pretty good on my own though

[@johnhonda93]

If you run staged injection would you be able to have the first stage be pump gas, for cheap driving around. But have a complete seperate fuel system for the secondary injectors running methanol to raise your octane automatically when you're in boost? Or would there be an issue with them being different fuels?

[@CurtisBarros]

The fastest race car "circle track" is a Sprint car. Naturally asperated fuel injection "ITB'S" But they control the fuel speed by low and high speed pills "check vales" and the Barrel valve controls idle speed and part throttle until butterflies are wide open. "Veg explanation"

[@BacnDesigns]

Would their be a logical explanation for running no filters on the stacks for more power? I had a autech SR20DE with an ITB setup, tuned based off tps with a vacuum log, quite short stacks, was super reliable, however if I put filters on the stacks it felt severely down on power, gull throttle bogged extremely hard. So I just never ran filters and had no issues 😅 This was quite a while ago on a little microtech, so I guess it could be purely tune related.

[@clutchboi4038]

Yes the way to put filters on the ITB velocity stacks would to basically do what sport bikes do, have a big air box surrounding them with a high flow filter that has air ram tubes forcing air into the box when the car drives forward. Putting a filter on each tube is too restrictive and basically kills the whole point of a velocity stack which is to give the air velocity as it goes into the engine.

[@davidvaughn7778]

In short, runner length determines low/mid/high rpm power ranges. ITBs, STBs, or carbureted doesn't matter.

[@clone4211]

Okay, now what about the carburetor equivalent and fuel dropping out of suspension in typical manifold design?

[@egeayvala1799]

They are worth more putting on big ass engines like V8,v10 12,because to be honest a V6 is probably already supercharged or turbo charged

[@ImranKhan-by2nb]

All the technical comments are cool, but can I say how soothing the presenters voice and accent are? Love the way you sound my dude.

[@guiltspeedsupra2036]

So which application is best for boost such as Rb26 itb vs single 82mm throttle ?

[@henrytomai6169]

Didn't Mazda use adjustable velocity stacks on their Le Mans winning 787's?

[@onelowvdub]

I was literally just researching this yesterday

[@rifleman7313]

Have an ITB throttle body ever effectively been used along with a turbocharger?

[@mrb.5610]

Could really do with dyno curves to back this up .... But, yeah, let's be realistic !

[@bigcazza5260]

whats an intech/early barra intake like? pretty good for n/a with bolt ons? exhaust on the intech is trash so i extracted an 2.5 inched it but im looking at the other side now, or just head work and new filter and she good?

[@joshfromalstate8438]

As far as i can tell, the reason ITBs are so popular on old ford push rods is because the factory intakes are extremely restrictive and ITBs will give a increase in power on almost all ends

[@Goldenhordemilo]

ITBs sounds good for tuning each piston as no cylinder is the same

[@sandasturner9529]

True words

[@techo61]

All this talk about length and girth, my mother warned me about this type of talk...

[@bvward]

Matt, are you aware of a dbw device to replace the tps on ITB's? If available, might it ease the tuning "giving birth" fiasco? Used to use vacuum logs on my dual carb VW's ;)

[@ChristopherJohnson-un9gb]

Didn’t talk about the difference in throttle response because of the lower total manifold volume…

[@P0LARice]

The engine I am using can make a lot more power than the drive line setups that easily fit in the car can handle anyway so maintaining or perhaps even losing a little power for a visual and auditory aesthetic seems like a good deal in my case. Thanks for the info.

[@williamhardes8081]

i have seen what i would describe as a hybrid of the two. individual runners with velocity stacks but the velocity stacks then enter a plenum with with an individual throttle body. is this a best of both worlds or artist license on the problem.

[@Wes_Mo]

bit confused on your explanation of the pressure wave saying the speed changes. pressure waves travel at the speed of sound. thus the longer the inlet, the lower the rpm the 1st order increases are made. the pressure wave never changes speed.

[@8alakai8]

people modding yamaha mt 07 should watch this i was saying from the start to them and even tested it if you change the intake make it shorter and bigger you will lose the downlow torqeu you will gain top end but for street riding i like the low end torqeu

[@BoogalooShrymp]

Good info. Is the Haltech DBW feature compatible with later model super bike quads with fly by wire or similar E throttle controlled throttles? What's the entry-level Haltech ECU with DBW? 1500?or can you option 550 or 750?

[@haltech]

You can contact our tech support team directly via www.haltech.com/contact-us They'll be more than happy to help you out.

[@bigcazza5260]

intake runner length on a car engine works like exhaust spacer on piston port 2 stroke, shorter gives higher rpm performance because the pressure waves can operate quick enough at higfh piston speeds but long ones time the pulses better to get air in at lower rpms

[@manitoublack]

love the itb's on my GTiR. and have a set of 50mmØ throttles on the bench for a KA24DE project for my 180B Datsun.

[@Danger_mouse]

GTiR bodies are great and can be had pretty cheap. My non mechanic son managed to adapt a set onto his N14 SSS Pulsar AND run off the stock ECU - Only using me as a phone a friend when needed, as I was away for work 😕👍