K-Series Throttle Body Comparison Dyno Testing - 8Th Gen Civic Si

Tuning by Nick
Toronto, Ontario, Canada
[e-mail]
Dynojet 224xLC Load Control Dyno Tuning
2008 Honda Civic Si Project Car
K20Z3 Internally Stock Engine
K-Tuned 3.5" Cold Air Intake
K-Tuned 72mm DBW Throttle Body
Acura RDX Injectors
K-Tuned Stainless Steel Header
K-Tuned 3" Cat Back Exhaust
Hondata Flashpro

[@Tylernunz]

Would love to see some header/exhaust comparisons

[@austythesnowman5093]

Absolutely love this comparison series!! Super informative and I like that there is an actual dyno pull for each piece.

[@copperkeyracing6167]

0:41 "Do larger throttlebodies make more power?" Short answer, the answer is no, because the stock throttlebody is soooo large to begin with, and anything larger is mostly overkill... relatively. What you have to understand here, is that there is a relatively small window for the optimal size, too large and lose power, and too small and you lose power. I say "overkill... relatively" because the stock throttlebody is 61mm on a k20z3 (62.5mm on K20A/K20A2/K20Z1), and there is throttlebodies on the market for kseries that are 90mm. The 90mm is for 1000hp builds, while the stock throttlebody is large enough for stock and light mods. So, then you need to split the difference, and then you can go for the amount of power that splits 1000hp... so, 75mm for 500whp. 65mm for 250whp... and that's basically it. So, if you are stock block, 65mm is plenty large enough. If you go to 70mm and you are at 250whp, you are on the larger side of that optimal window, but you are still ok, not gaining anything but not losing anything, if much. If you are at less than 250whp, then, yes, the 70mm throttlebody is too big. Max power, the world record, on a stock block on a K20A/K20A2/K20Z1 is 245-250whp on a dynojet (250whp for the K20A, 245whp for the others), but that's having the absolute best mods, and all the best mods that make power, and I mean super smooth and optimal flowing. I would say the optimal window is 64mm to 68mm for optimum power at that power level.

[@Willis-de5hx]

I have a 70mm on my 260 hp na .. love it

[@boblast5582]

Did you watch the rest of the video? People also say that a 3” exhaust is too big for an NA 2.0, 3.5” intake is too big for a 2.0, etc… point is you gotta test and see, theory takes a back seat to actual test results.

[@copperkeyracing6167]

@boblast5582 Exactly! And sooo many independent 3rd party tests have been done in the past to back up that with a stock block and with the best boltons, making 245whp on a Z3/A2... a 64mm TL throttlebody makes all the power and any larger and there is no gains. If you watch tests from non independent 3rd parties, aka they have personal-stake/vested-interested in claiming higher because they sell them, then they play plenty of tricks/scams to get you to believe their hype.

[@boosted__demon6852]

You should do a comparison of full exhaust vs straight pipe vs open headers.. I think that would be a pretty cool comparison!

[@alexK661]

engine masters did a test like that, but on a v8

[@Kingblow69]

The “drivability” and “throttle response” isn’t exactly ‘improved’. Because it is a DBW car, the calibration for Pedal to Throttle angle is what determines the “pedal feel” and “throttle responsiveness”. OEMs don’t map their throttles 1:1 and you really shouldn’t either. With that said, when you DON’T change the throttle mapping, but change the throttle size, what you’re doing is basically increasing the airflow through the throttlebody at lower throttle opening angles. In other words, it takes less throttle to accelerate just as quickly with a larger throttlebody as compared to a smaller one, WITHOUT CHANGING THE MAPPING. It is definitely a “feel” thing and cannot be quantified.

[@DiegoRodriguezAW11]

thx for taking your time to show us this kind of things mate

[@milanmastracci]

Nice and informative video! Good work Nick 👍

[@vtecbanger3180]

Thanks for taking the time. I just bought one to compliment my jr supercharger

[@rogerkasan1]

Sum it all up, throttle bottle effects the throttle response. Overall not many gains

[@HondAcura111]

I have either 68 or 72mm on my rsx cant remember but u def notice the throttle response I love it so much! But don't forget u lose cruise control.

[@werksguy]

really u loose cruise control

[@oscaralejandrofernandeztap4289]

Excelente video, felicitaciones muy detallado el analisis que has hecho con cada Trotle Body en comparacion con el K de 72mm. Super, muchas gracias

[@davelassell]

I wonder if you could tune these even closer with a 50 degree VTC. Your videos are super helpful planning my K24 build.

[@oscarjsm24]

4 hp gain and almost no torque gain. I’d just stick to stock 60 mm if doing fbo. Otherwise bigger tb is overkill for just fbo setup. But def ideal for built head/all motor setup. Thanks for the video!

[@Uwusenpaiii]

Like Nick said it’s something you won’t notice on dyno but it does definitely makes power response much more greater on your car.

[@detta1413]

Nick please make a video how to w step with flames for hondata flashpro

[@876forlife2]

facts

[@boblast5582]

What’s long term use look like with the bigger TB’s? I’ve seen many burn out the internals of the DBW cause it requires higher amperage to operate? Even K-Tuned recommend a stand alone ecu to run their 72mm to guarantee no issues when I asked about it.

[@94tegLSatMSC]

Was the inlet on the intake manifold bored to match the size of the throttle body? I saw in a previous video you had mentioned you had multiple RBC manifolds that were bored to match each throttle body, but I didn't notice it mentioned in this video? Could change results a bit.

[@e_yiizy]

I guess larger TBs aren't really worth it unless one wants to go FI, it seems?

[@itachithegoatg6803]

Excellent info I would like to see port match 70mm no spacer

[@Hanschepu]

the spacer actually helps a lot - LHT did a spacer comparison with a Mugen FA5 and it gained about 6hp on a stock throttle body

[@Tony-montana-666]

Thanks for the video

[@mykov3677]

I wonder how much difference a fully ported RBC will make in a setup like that. Awesome that ported inlet makes that much of a difference on stock TB compared to 72mm! I'll be dm'ing you soon for a tune date (hopefully less restrictions by then) and not forget my hondata this time lol. The clutch was definitely the issue last year, as soon as I put the comp. stage 2 kit, worlds of a difference. Ported rbc is already on, and just waiting to put in type-s oil pump, and skunk2 DIC. It's probably better to get tuned asap after the drop in cams, right?

[@jesselee4405]

For sure

[@workhard6445]

Would love to see it on boosted application 😊

[@WarningHPB]

thanks for the video's Nick some invaluable information there :D

[@MrKylev35]

Good stuff sir!

[@EatSleepHondaKseries]

What do you think about the 90 mm throttle body for civic si 2008

[@PiterStreak]

Heard it has issues

[@ivtec845]

It's also the largest t.b u can fit without porting out the iac

[@GianniAdduci]

Thanks Nick

[@a7xogg]

Real question is how did you get all the throttle bodys to idle good so quickly

[@Maggot00679]

I am also wondering 😂

[@user-hh4hc2lt6e]

Run it at 3k rpm for 5-6 minutes to do an idle relearn

[@BunnyBUNGALO]

I wonder how the tsx tb with spacer woukd compare. Its what i am currently running

[@emrvrnl]

Thanks Nick.I like watching your comparisons. If vtc angles are changed maybe different results. Because tuned for 72mm TB.What do you think about it?

[@dav31078]

Are the differences in gains with throttle body sizing similar to the 2.75” vs 3” exhaust argument?

[@rehcvlee6577]

Don't you have to tweak the tune for each different TB? More air flow vs less air flow.

[@dr.markusraindl1745]

Was the intake manifold ported and to which size?

[@alfredoventura4727]

Try a spacer between the intake and throttle body

[@JimmytheGenius]

Yup! Cam limited just not enough lift/duration to allow more air in.

[@ethanrainsford4251]

been looking into things like this heaps for a stock k24a/k24a3 whichever i can find with everything i need to swap plan on going kpro wih 4-1 headers 3inch exhaust and a 3.5 inch induction kit with mild porting and polishing to the intake manifold and the head so seeing this makes me want the 72mm tb looking for driveability over anything thats why the plan is all motor

[@t_money_third9654]

I can't believe it only made power above 7k rpms. My engine won't even Rev that high

[@fa5silencio]

Awesome video. quick question? What kind of tune I need to run the 72mm? I currently have a tune on 93 all bolts on, my next upgrade would be the 72mm throttle body.

[@OffTheLineVideos]

What kind of intake you got? I got same car just went k23 injectors as you. I got k&n down to fender wondering what you got

[@carterpimp1]

You the man 👍🏽

[@GonzalezRoyalPythons]

I wonder if grams 72 Tb is the same as the ktuned one

[@MrDjcosmic14]

Great idea

[@estewar03]

Does it matter what vehicle the J35 TB comes from? Or as long as it's the electronic are they the same between Car's & SUV models & what about year?

[@werksguy]

Hey Nick! I heard you need to swap the motor from the stock throttle body into the J37 throttle for voltage reasons is that true at all? or is the J37 just plug an play and no swap needed? I am on the fence about the j35 or the j37 but leaning towards the j37. I will getting a dyno tune after i pick the j37 or the j35 tb? Thanks! I was thinking of going of port matching the j35 or the j37.

[@Coaco98]

Curious if you would see the same results if you hadn’t ported the intake manifold.

[@mykov3677]

I personally had that so I could comment something useful :D stock RBC and 72mm TB = Felt barely anything, but heard a lot more air suckle noises inside the engine bay Inlet ported RBC and 72mm TB = Instantly improved throttle response, and felt much peppier then I got tuned by nick shortly after, felt incredible until my clutch ended itself. Just couple weeks ago installed stage 2 clutch, lightweight flywheel, and fully ported RBC (same mods everywhere else) Fully ported with 72mm TB = holy f**k what a lively difference. Granted, old clutch was destroooyeeeddd, so may have some power loss from the get go. The drivability improvement is worth it 100% though, just slight revs are so responsive, you can tell the car is tasteful and not some half-effort modded.

[@Onelovej]

@@mykov3677 thanks for all the info good to know

[@mykov3677]

@@Onelovej absolutely, I haven't uploaded in a while but check out my build as of last summer, not the best video and not much changed I dont think, but I'm hyped to do a vlog update by next spring. Only thing I really added in this year is a 0km OEM FD2 Type-R cluster, and the fd2 type-r steering wheel. & lastly touchscreen dual din deck. Otherwise been slowly recovering from a fat fall in life lol

[@Onelovej]

@@mykov3677 right on I’ll check it out🔥💯

[@bsandhu808]

Great content Nick! Do you delete the coolant passages on the throttle body? See any benefits to doing this? I live in Phoenix so I’m not worried about the benefits of running warm coolant thru the throttle body. TIA

[@Maggot00679]

I live in Florida, deleted mine. If there is a difference, it's marginal. Have yet to hit a dyno so no hard numbers, but it's nothing noticeable..... During warm weather lol When temps hit the 50-60s down here, the car pulls noticeably harder more consistently than before the delete.

[@dy1ngx2xliv3]

How are the map reading for each pull if you know? Wonder if one had more suction then the other.

[@ivanalonzo35]

Nice video man question on what car year and model can i get the j35 direct fit for the 8th gen si thank u !!!!

[@davidlongoriajr1858]

Will those Rdx injectors do justice in the r18 motors for this year (non si )

[@kajida]

Would love to see the same kind of test buy done on a turbo k24

[@Onelovej]

Me too

[@PiterStreak]

While NA the throttle body becomes a restriction of the engine sucking in air, In a boosted application, the air is forced through so I doubt there would be any different

[@lmaoboy8546]

Hey Nick I was wondering if I can use my PC for KTuner V1 . I don’t have a laptop but I know you need to have your laptop connected to the device and your car, but I have a PC.

[@tuningbynick]

If the USB cable reaches, you could definitely use a windows based PC

[@roskataqv]

Would the difference be the same if it had a k24 bottom?

[@starscream42]

So it's pretty much worthless, nice to know. Thanks!

[@davidlongoriajr1858]

Going towards boost with si intake manifold this throttle body just need fuel

[@athiam152]

Nice video

[@obriannelson7168]

Hey Nick what size exhaust was on this car?

[@MrCrowley925]

Hey nick I was wondering if I have a mishimoto intake that goes to the stock box with a drop in K&N filter on my k20z3 and maybe get a Throttlebody of the ones that you’re showing if I get Flashpro cold you send me a tune and can I upload it to the car not looking for everything crazy just want something fun to drive thanks again #HondaGang

[@ModernWarfare924]

He is not doing charity work brother

[@MrCrowley925]

@@ModernWarfare924 I’m not asking it for free bro not that kind of person

[@Zillerz3]

@@MrCrowley925 mmmmm don't try to mod your parent's car...Stick to Cod for now with that sentence structure. I like that you're repping Honda though, so you're on the right path #hondagang

[@rmarli17]

How much did you port or increase the header?

[@coreyburns2074]

That’s about 260 hp that is monster numbers on a small car I bet that civic will fly

[@BuddhaBuilt401]

Awesome video curious does this car have headers ?

[@daosavat]

Check description

[@almiribrahimovic5239]

K20--INTEK-AIR FILTER-HEADERS-RACING EXH-----228HP.....GOOD...

[@joshuayammer1994]

J37?

[@Adumbpriice]

Port match or it doesn’t even matter.

[@DoHc3222]

j37 throttle body and port match....

[@copperkeyracing6167]

Clearly just marketing for Ktuned. Not a fair third party test, by far.

[@siraznallot]

stock rbc port?

[@copperkeyracing6167]

6:49 Just two pulls? Seriously? Not going to do a full tuned like the benchmark to do an apples to apples comparison? Not going to port match the manifold to the throttlebody, not going to put a equally sized cold air intake to match the flow in and out of the throttlebody. Wow, what a slacker. Bogus Test.

[@jesselee4405]

the manifold was already port matched to the biggest TB

[@copperkeyracing6167]

@@jesselee4405 Then, get another manifold, and port match it to the next throttlebody, so on, and so forth. It's not a good comparison unless it's apples to apples comparison. Port matching to the one you secretly are wanting to praise, is cheating.

[@JCnordic2983]

You're going to lose mid range torque with the bigger throttle bodies

[@user-wg6jr7cq8o]

stupid test you change the throttle body but do not change the size of the inlet in the intake manifold

[@copperkeyracing6167]

1:10 The reason it feels "quicker and faster" Is because you lightened your wallet. Weight savings, and the psychological "I paid more so it must be better." LOL. Bogus test.

[@salteveline]

yep thats what it is, u paid u expect pschological gains 😅

[@copperkeyracing6167]

LOL. Not a true test. Slacker. Failed to port match a new manifold to each an every throttlebody and match in the intake size to the throttlebody. WOW.

[@salteveline]

yes port matching is a must! but for budget newbies who cares about bolt ons - it is informative :)

[@copperkeyracing6167]

@@salteveline It's misleading is what it is. It must be an apples to apples comparison. Hondata has done a ton of tests... and it was over 10years ago... and they found that going from 61mm to 64mm was "About 2hp from 6000 rpm up and pretty close to the margin for error of the dyno. A bored throttle body will probably show better gains if tested with the Toda N2 Cams, but it is pretty low on the bang for the buck list at this point." The fact is, as you go smaller on your throttlebody, there will be a point where the engine will be able to out flow throttlebody, and the throttlebody will begin to become a bottleneck. For a stock motor, with full bolt-ons that size is about 64mm, as the results of Hondata's test. The other side of the sizing also causes an issue. As you go larger on your throttlebody, there is a point where the engine will be flowing to its max potential and then eventually the throttlebody will become so large that it becomes a large resonator/chamber where the air is not able to flow properly and becomes a hindrance. For a stock motor with full bolt-ons that size is about 70mm, as the results of Hondata's and many others test. As you can see there is a window where the sizing does not hurt you, outside of that window you will lose power... and therefore, any throttlebody that is 64mm up to 70mm, on a stock motor, you are plenty large enough. If you have no bolt-ons, then your window may be 60mm to 64mm. If you do all the bolt-ons possible (intake, header, exhaust, intake manifold, cams), then your window increases to 64mm to 70mm, where there is no loss of power. If the stock throttelbody on an RSX-S/EP3 was 60mm, then any bolt-ons would immediately throw you outside of that window... but it's not 60mm, it's 62.5mm (TSX & 8th gen Si is 61mm), which is why a throttlebody is way down on the list for bang for the buck list. Once you are full bolt-ons, then 62.5mm becomes too small, and you can have the factory throttlebody bored to 64mm and you will be at optimal size for all bolt-ons. This is what I recommend, that you port the factory throttlebody on the RSX/EP3/k-swaps if all you are going to run is stock block. There are a few companies that remove the stock butterfly, bore the throttlebody, and put in a larger butterfly... and keeping all the sensors, cruise control, reliability, etc that comes with the factory throttlebody. I recommend King Motorsports (they are the US Mugen distributor). Maxbore is another company, but I have seen very poor results from them, in my experience. Now, if you go boost on the stock block, or go with a high compression all-motor built block, then that's a whole different story, and you should get the aftermarket throttlebody. 70mm would be minimum on that window. Be prepared to silicone the heck out of it, as it has really poor mating surfaces that are not true.

[@mondecruel1866]

@@copperkeyracing6167 thx for that post it is a good read 🙏🙏

[@copperkeyracing6167]

LOL. Garbage test. Nuff Said.

[@javiersantiago1375]

Firsttt

[@Jev0nep3]

no traction so try second lol