VARIABLE VELOCITY STACKS TEST on TRACK (🇫🇷sous-titres)

Testing this upgrade on track in Donington Park during a NoLimits Trackday + showing you the gains with Dyno testing.
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[@andypatterson9848]

If you uploaded a new track day ride every week, I’m 99.999% sure no one on this channel would be upset ;)

[@FunnyMuffler]

I honestly thought this was an AE86 test at first and just clicked haha. Very nice to see this setup on a bike, amazing with that variable setup. _FMG_

[@JamesBalazs]

Same - we need Garage 4AGE to dyno test a set of these now 😅

[@cheapscifi]

Yah I was thinking along the same lines. A few hp in a car isn't going to be very noticeable, but on a bike can make a huge difference.

[@nicoleibundgut534]

@@cheapscifi you won't gain any horsepower at least no top end ones. But you will gain torque in lower rpm's which definitly will be fun in a car aswell. Some 4age have variable intake lengths already.

[@wannabecarguy]

T-vis

[@TheSudsy]

Technical expertise as well as a solid racer. Excellent

[@ianwarren]

Probably a prerequisite to be an effective MotoGP test rider to have a good grip on all the technical aspects of bike, engine, suspension, brakes and especially setup so he can give his teams great feedback and suggest avenues of improvement! Fascinating videos as always from Sylvain 👍 thanks!

[@tspracing8835]

Ultra intéressant, simplifié pour que ce soit très clair et compréhensible ! Merci.👍

[@jdsstegman]

Mr. Venturi would be proud. Something that impressed me was this throttle hand position. Looks like such a light touch on the throttle tube. I find myself at times death gripping the throttle. Then realizing, stop that! Lol. Loved the video. As a mechanic, I believe there is power to be made with this set up.

[@johnkattenhorn]

Ray and Kev are a pair of geniuses, I had the privilege of being with them quite a bit this year and I have stacks ready to be fitted to my BMW M1000rr once I've finished running it in!

[@findus605]

Good to have you back with new content Sylvain. look forward to more interesting videos during the winter months.

[@ChasingTenths]

Stunning video mate, lots of bits to learn . PCR dyno’d my bike too, brilliant people

[@asanofr]

J adore ce que tu fais Sylvain, explications au top ! Et bonne chance pour la suite ! ;)

[@poireauer6517]

Pas mieux 👍😉

[@andreschondelmaier4834]

Awesome! I had thought about variable stacks a long time ago . I'm glad to see someone has done it . Great work .

[@GladiarOfDestruction]

Yamaha R1 has variable velocity stacks, stock (;

[@TheJagjr4450]

x2

[@bsimpson6204]

Some years back there was a mod for the BMW R1100RT motorcycle where you changed the inlet trumpets for those from a GS1100 which were way longer, the improvement in torque at low speed was very noticeable, made the bike much nicer to ride. Btw, Porsche fitted variable velocity stacks to at least one of its cars, a flat six, for the same reason. Clever stuff.

[@dutchsailor6620]

1100gs trumpets are longer and smaller in diameter, so you get a higher gas velocity into your cylinders. First series r1100xx also had cylinder heads with larger valves, downside of these larger valves was that at lower revs they are partially shrouded by the cylinder wall, so you loose some bottom power. Best mod was to mount r1150 throttle bodies that had 4 hole injectors instead of the one hole injectors of the R1100xx. A lot smoother ride.

[@Jonathan_Doe_]

Alfa Romeo did a variable length intake on the 2.0 16v, Audi had on on the 30v, both of those were just plenums with a different opening to let air take a shorter path when a flap opened though.

[@dutchsailor6620]

@@Jonathan_Doe_ Its still very common on performance motorcycles.

[@bsimpson6204]

@@dutchsailor6620 cheers Dutch, the 1100 series does need help in smooth running

[@dutchsailor6620]

@@bsimpson6204 So many strange decisions were made by the designers just to keep us scratching our heads in despair, but once you got it right, its the best ride there is.

[@tombigelow7391]

Love ur riding skills😎 Love the camera work👍

[@andypatterson9848]

If you uploaded one track day ride a week, I’m 99.999% sure no one on this channel would be upset ;)

[@DudeMungus]

This is so amazing 👏🏾

[@UNKNOWN-zb3qm]

It's fascinating to watch you ride that thing

[@karljay7473]

That's pretty impressive power gain. Interesting design too.

[@cecilwilson5442]

When you talk people listen because you have been there and done it with various manufacturers and racing series,, brilliant stuff ☘️☘️☘️☘️ from northern Ireland,,

[@Wtfever..................]

Absolutely awesome!

[@jhellnowh]

Nice one Sylvain, thanks

[@proto7688]

This is amazing to see

[@flyingdutchy01]

that rack full of leather suits. thats a dream. some epic designs and liveries

[@kingofbrutaltheocracy9201]

Thats really cool!

[@lametraserillos1]

great rider !! salutes from spain 😉

[@fivespeed3026]

My old 2009 R1 came with these stock.

[@returnoftheduke6103]

Merci pour cette vidéo. Toujours cool d'avoir tes explications. Juste pour ma culture perso : ça correspond à quoi le creux de la courbe bleu entre 10000tr et 10500 tr/min sur le graphique stp? Est ce que c'est dûe à l'admission variable du coup?

[@devinwagers3134]

Brilliant design

[@curvs4me]

Nice pieces.

[@deckum23]

My 1986 aw11 mr2 had t-vis toyota knew what they were doing.

[@bicivanaswegen2077]

Great video, big Suzuki fan since 1970. Sylvain tell us what are you up to next year ?? Wil a private team take over the Yoshi bikes for EWC ??

[@elijudkins2578]

I’ve been wanting to see this since I saw someone do a 4 ft tall air stack on an ls

[@fabiodeamicis92]

Hi Sylvain,I have been mounting them for some time and I confirm the improvement in delivery and power, mine are Venturi System in ergal

[@BienvenuMotorsports]

But yours are just the lower stacks and not variable like the StringerStacks right ?

[@fabiodeamicis92]

@@BienvenuMotorsports yes

[@kloppskalli]

if i knew that you're going to discuss the dyno at the end .... i was really mad when you showed it for just 2 seconds at the beginning.. 😉😅

[@dalerogrrs7787]

Made those as a kid , to have smooth power on them old two stroke dirtbikes , helped smooth out power band,

[@mrmete]

@dudemungus now i see why you get out so fast in your races💪🏾

[@Tracer847]

The MT 09 2019 has a different length velocity caps is it perhaps more correct if an exhaust has been installed to fix? velocity caps same length????

[@NvTwist]

Reverse the setup…. The lower the RPM the Longer the stack and higher the RPM the shorter it the stack length. For example a one cylinder with 1 intake/ 1 exhaust. The dwell time from intake valve closed to open takes more time the lower the RPM is & takes less the higher the rpm climes. The pulse wave front created at closure travels up the intake path until & exits at the first opening or large volume transition (top of velocity stack) creating another wave front that starts back down towards the intake valve. Without considering air temp to simplify the example the Velocity stacks length determines the it takes the wave to travel up and back to the valve, timing the wave front to hit valve as it opens provides a “super charge” Effectively filling the cylinder with more air & fuel. Same trick is used with carb intake designs, Low-rise, high-rise intakes each have different power band outputs. I don’t think a fully variable velocity intake has been pulled off yet but a few duel band systems have. Set the stack length the longest you can fit, figure the wave front travel, as the rpm climbs slowly shorten the stack to match the travel time needed until either max rpm is reached…. Or the shortest stack possible and boom ya have a game changing setup providing more power across the widest rpm range ever provided. The velocity stack has to be a continuous tract, raising a fixed length tract above the intakes opening is a dual band intake system not a true variable setup. Keep up the work.

[@flamintasty]

LMAO another KZbin expert telling people who run race teams and a World Superbike Champion and MotoGP test rider how to do it. You gotta love the internet 😂

[@NvTwist]

I’m not expert but I have first hand experience from testing multiple intake runner lengths. But are you just another unimaginative KZbin troll or have a counter or actual opinion of the topic?? ⏱️

[@NvTwist]

@@flamintasty 🧐 hmm caught that🦶 👄 🦠

[@arthur1418]

Awesome!! I would have liked to hear a bit about the technology behind the variable velocity stacks. How does it work and why does it improve power?

[@Knights2theEnd]

I forgot the terminology but basically your velocity stacks will be most efficient (pull the most air) at a certain rpm, by being able to vary the length, you can make them most efficient over an entire rpm range vs just a specific rpm. If you type in "engineering explained and variable velocity stacks" into youtube, you'll find a detailed explanation.

[@arthur1418]

@@Knights2theEnd cool i'll check that out, thanks

[@Weimerica8841]

It's the same concept that Toyota (and probably others) use in their intake manifolds with long and short runners, controlled by the ECU. Never seen it applied to velocity stacks, this is awesome

[@adamkabich3130]

@sylvain are they available for CBR 600RR 2012, and where can I buy them please?

[@andrewhaick9043]

Are you able to share your shock length and fork setting. Are the ohlins forks the same as the RR fork in terms of length. Racing in canada and could use a little bike set up advice. Thanks

[@benjaminklein1829]

anyone else notice something wrong with the dyno chart? hp and torque meet in different places.

[@jaemelo2693]

What year is your GSXR mate?! I’ve been trying to find. Out the last year they used throttle cables before going over to drive by wire.

[@TheDealinDave]

my 08 r1 has this feature stock i wonder why they stopped doing it

[@sasanovcic]

Hi @Sylvain Guintoli, can you give us a little more informations about this variable velocity stacks? How they work? Did they move up with RPMs? Thanks.

[@KHIJAPAN]

RPM are not related to stuck only but to other engine parts like valve springs. Usually in stock form you can safely increase the revs to about 300 RPM. This item is all about torque and power delivery. Air fuel ration in the rev range.

[@ryurc3033]

Ok I want to build a single stack, and attach it to a gocart, just run it mechanically so it lifts at a certain throttle level? I do have a bunch of servos from rc stuff I could try to use .....wow this spawns so many new ideas

[@serkanilbeyi8614]

Im building a trackbike L8 and I also will change the chain kit. What nr sprockets do you use? I live in The Netherlands so i will be riding a lot on the TT circuit of Assen.

[@SylvainGuintoli]

I use 15x42 in UK. Kinda works everywhere

[@nickrider5220]

Will you still race for SERT next year Sylvain ? These variable velocity stacks make a big difference 👍

[@pomplardpanam8591]

Suzuki is out of it too

[@scoc253]

@Sylvain can I know what brand and kind of DOT brake fluid you are using with your set-up? is that abs deleted? thanks a lot brother.

[@flamintasty]

ABS is deleted and he is using Motul brake fluid.

[@johnnyblue4799]

I wonder, do the deeps in the curves, beginning at around 10000 rpm correspond to the raising of the stacks? It looks like that's where the transition starts and it ends around 10800 rpm.

[@SylvainGuintoli]

Yes

[@freelancerider100]

That is also where the vvt does it work.

[@adamkabich3130]

@@SylvainGuintoli are they available for CBR 600RR 2012, and where can I buy them please?

[@antoinem4401]

Intéressant

[@JoeOvercoat]

I came for the intake engineering, and found a sporting opening.

[@FlavienS57]

Is this system an ON/OFF switch ? Or does the length vary all across the rpm range ? With the print, I assume it changes valve length at +/- 10k rpm ?

[@shaynegadsden]

It's just on/off since it doesn't vary the length the just have a tall stack that lifts off the short ones at the target rpm

[@ptolamaustittan]

Check your brake line the green tube it looked like bubbles in it

[@NOONE-hp8bw]

Do you think they will make some for 1992 xj600s diversion 😂

[@veryrare7647]

can i get some on my toyota beams?

[@apashe974]

Ca me confirme que La France et le R&D sur la combustion interne c est finito Je m’abonne 👍🏽

[@rickybobby7660]

Didn’t realise the OEM’s went away from variable lengths inlets, Yamaha had them on the 2008 R6!

[@SylvainGuintoli]

Yes I think only Yamaha R1 and BMW 1000RR have them as standard nowadays

[@gin-tony]

quoting the Cycle World magazine October 2005, page 45: Massimo Tamburini: "By using an intake pipe of ideal length for the desired RPM, a torque gain of the order of 10% may be achieved - but only across a limited RPM range. To have both a robust midrange (the Tamburini's peak torque on the CW dyno comes at 8,700 RPM) and strong top end calls for having 2 different intake lengths. This is just what TSS delivers. The MV's four throttle bodies have short, permanent bellmouths suited to top-end power, but a set of moveable extension bellmouths is carried on a pair of linear bearings. Below 10,000 RPM , the extensions are in place, creating a longer tract that boots torque. Above 10,000 revs, a Pierburg pneumatic actuator (run on engine vaccum) snaps the extensions up and out of the way shortening the intake tract to boost breathing and thus power on the top end. This is a two state system. It is not progressive as the extensions are moved in or out of use within 0.15 of a second" He is genius. Yamaha just take his idea, and realize that without pneumatic actuator.

[@rickybobby7660]

@@gin-tony I’ve worked on 80’s F3000 engines with variable length bell mouths and Mazda used them to the extreme on their 90’s 787b. There hasn’t been innovation or genius in motorcycle engineering since Walter Kaaden😆

[@crisnmaryfam7344]

@@SylvainGuintoli The gains at the top end werent worth it for them. Thats why. Variable is great for all around power. Those moto gp guys are in the top 10% of the powerband 99% of the time, so the lower end power you gain from the variable setup is irrelevant. For a lower skilled, "slower" daily rider, weekend tracker. The variable set up is king. Its like when you see those old muscle cars, come out in the summer for the car shows, and you see them stall at the stop light or sign, because they are tuned for the top end, they cant stay in idle without holding the brake and feeding it gas (thanks to a really lumpy cam lobe), They make stall convertors for this but again theres a trade off with that also. Some street models still use these variable setups because of this.

[@crisnmaryfam7344]

@@gin-tony After further experimentation and testing , its not the "fixed mouths that is suited to top end power" but the longer/shorter inlets, They "move" the power around the powerband so to speak. Longer will give higher top end power, at the expense of low to mid range, and vice verse. Check out Chris Moore on youtube "2022 Hayabusa Velocity Stacks PROBLEM SOLVED!" and "Do you have a 2022 Hayabusa and Want 20 EXTRA HORSEPOWER ?!?! I have the SOLUTION!!! MOORE MAFIA" He gets a few different kinds of velocity stacks and tests them on a dyno. Special CNC billet ones from Cypress and run of the mill 3d printed ones like in this video.

[@jetsh1ftman746]

Do they make these for cars?

[@lasphalteur]

Elle a la santé 👍🏻

[@omi8822]

Can this work for NA car

[@byloyuripka9624]

Did these not come stock? Yamahas have had this for a decade or more?

[@arataracing]

Few bikes have this as an OEM as you probably figures out.

[@jamesperreault4506]

i put these stacks on my 2010 zx6r i gained 3hp from 9500 on and gained 5hp of torque

[@thewebkat]

Hi Sylvain ! Can you please tell me why Suzuki don’t put you to race for Joan Mir ?

[@SylvainGuintoli]

I was still recovering from injury but all good now.

[@brendendyson8470]

God you can see how loose your hand is on the throttle, that was a great bit of footage, does dangling your foot wear your boot out quickly

[@SylvainGuintoli]

Loose hand is key to (kind off) relax when needed and use more strength on braking. Will do a tutorial on this soon. Boots get used fast yes😆

[@brendendyson8470]

@@SylvainGuintoli cheers mate , such a shame Suzuki is out of motogp and endurance racing

[@pomplardpanam8591]

@@brendendyson8470 What R U gonna do bro next year ? Kawi supersport ?

[@r1learner178]

Cool, they have built a 2007-08 Yamaha R1.

[@garyhoward4064]

How does it work?

[@Al-of3zp]

Love the French/Cockney accent

[@pauln6803]

His wife is from Leicestershire, innit?

[@webplayerxvii]

What is the bar end extension on the throttle side?

[@flamintasty]

Front brake lever guard

[@Guds777]

What is this black thing on the right handlebar...

[@flamintasty]

Front brake lever guard

[@PAD32]

I wouldn't feel secure having 3D printed stuff in my air box. With vibrations on the long run, couldn't it start throwing bits of plastic in your engine some day?

[@henrikforsberg683]

There is different levels of quality for printed parts, probably not made on a “wish-printer” 😁

[@crisnmaryfam7344]

Should check out an Americans youtube channel. Chris Moore. He does a lot of Dyno tuning (basically all he does dyno and drag race) He has done some testing with a few peoples product like this. He is also a Suzu guy.

[@flamintasty]

He doesn’t run Superbike teams though, Paul at PCR does.

[@boxster21]

Are they available for CBR600RR

[@BienvenuMotorsports]

Yes, in fact they were tested for an entire BSB season on a CBR600 based Moto2 bike you can order them here www.veloxracing.com/product/stringerstacks-electronic-variable-velocity-stack-kit-zx10r-gsxr/

[@6.5creedmoorrips6creedmoor2]

Yamaha has had varible stacks since early 2000s

[@Gouranga552]

listening to your accent changes depending on the word you say makes me feel like im having a stroke.

[@yannguyery6735]

195rwhp is ridiculous on a street bike after a few tweaks! Out of comparison I wonder how many rwhp you had on your Aprilia when you won your WSBK World title in 2014?

[@SylvainGuintoli]

Yes 195 feels good😀 Back in ‘14 we had about 240 rwhp and over 16,000rpm. From ‘15 they introduced new rules that did bring power down.

[@yannguyery6735]

@@SylvainGuintoli 240rwhp dang😮!!! I wasn't expecting that much, far out! Nor did i know rules went more restrictive in 2015. I'm assuming this was driven by cost limitation, unless they were already trying to level the field like these days. Either way, thank you so much for taking the time to share this kind of info which I could only speculate on a few years back. As an early days 250cc and motogp fan, being able to reach out just like that, well it's priceless! Best of luck with whatever 2023 entails for you, it's a pleasure to follow you on track and through those great vids you send our way✌

[@KHIJAPAN]

Is there a website where we can buy these stacks?

[@SylvainGuintoli]

You can get in touch with Ray Stringer, his email is in the description

[@KHIJAPAN]

@@SylvainGuintoli Thanks. I already did. We will work together on my project bike. Since Suzuki is out of the game (unfortunately) Why don't you try Yamaha??

[@BienvenuMotorsports]

We are the worldwide distributor for StringerStacks - www.veloxracing.com/product/stringerstacks-electronic-variable-velocity-stack-kit-zx10r-gsxr/

[@Reginald-Erasmus]

hmm for all those that think this is something new, It was already perfected on the S1000RR by Bmw in 2009 already

[@SylvainGuintoli]

👍🏻 Correct, also standard on R1

[@stevebennett6593]

Anyone reminded of The Fast Show? :)

[@MrIngorodrigues]

On a bike that are 85% on full trothle its a small gain, on a street bike should be noticiable

[@creepychris420]

fucking awesome lad. this is the kind of channel i need to sub to. i never watched motogp but i like watching a real biker fucking send it. i google you to see who you are and why you are so good lol. i might start watch motogp now. lol you only have half a handguard. me too lol. idk where i lost it but feel bad for the car i was passing 😅 my foot pegs hit the floor leaning before my bars get anywhere close lol. guessing yours is low side and slide not riding that through traffic on that! 😂😂

[@richardlerud4322]

.......................... AIR CRAFTERS ................................??? SIMILAR CONCEPT ON EXHAUST SIDE ???

[@stephanelandre6943]

En français svp !!!

[@TriAngles3D]

In the 40s fighter aircraft used something similar. And, in the 60s some muscle cars had lengthened intakes which I believe they called Ram Air. At certain RPM this approach induced a boost like effect as the tube harmonics assisted in the pushing air into the cylinder. The idea is kinda the same as a 2-stroke exhaust or a pulse-jet. Quarter wave pulses are induce each time the port takes in air. Think of a whip slapping in air into the intake. The frequency of the quarter wave is a function of the inlet tube length. Longer length means lower frequency. Shorter length means higher frequency. By tuning the length to the pulse inlet frequency we can have the air be pulled into the tube and pushed into the cylinder. However, it is not exactly clear what is being done here. The harmonics are much more complicated here as the inlet ports are being lifted from the seats. We are not lengthening the tube but instead are lifting from it. Multiple harmonics are being generated. What they might be attempting to achieve is use the lifted tubes as fixed frequency half-wave systems that then assist in capturing surrounding air and push it into the cylinder. But the length of the lifted tubes is too short in my view...

[@lillnemo1]

If they lift the stacks, in fact they shorten it. Since the air gets sucked in from UNDER the lifted part.

[@TriAngles3D]

@@lillnemo1 Correct.

[@zqzj]

Longer stacks help with low end power. Shorter stacks help with high end power. Not sure harmonics have much to do with it.

[@TriAngles3D]

@@zqzj Has everything to do with it... Harmonics is the underlying wave mechanism involved. The harmonics here is the tuning of tube length to inlet frequency in air. The parameters for, for instance, a quarter wave harmonic system, include the speed of sound in air, inlet frequency and tube length. Speed of sound, inlet frequency need to be harmonically tuned to the inlet tube length.

[@zqzj]

@@TriAngles3D only in regards to planes about a century ago. Harmonics has nothing to do with modern automobiles since the engine RPM is highly dynamic. The old school planes were made to run at a constant (static) RPM, and the propeller pitch was dynamic. Constant speed props would greatly benefit from a harmonically tuned engine because the RPM would never change.

[@stephenhepworth3113]

That accent is v strange 😆 ( like a French Yorkshire man🤔😆)

[@Starfield6824]

You don't like aggressive throttle response😂😂😂😂😂😂. Champ yes but no engineer or tester😂😂😂😂😂😂😂😂😂😂😂

[@DrSkrungle]

the camera work in this is terrible. show the course too when riding

[@SoulReaper599xx]

First!

[@ringsting]

It's a thing of beauty.... sylvian as a side note is 13.1 the optimum AFR

[@crisnmaryfam7344]

Just saying "13.1 is the optimum" is incorrect to say the least. Theres too many variables you havent added to the equation here. It "MAY BE' optimal with X gas, and Y temperature at Z elevation.. but at G elevation with a B gas and H temp... 13.1 may cause the engine to detonate and shit a piston.

[@connor3288]

Ive heard all engines are different. I read 12.5:1 burns the quickest, Innovate Motorsports website has cool articles on air fuel and ignition timing.

[@jamesgeorge4874]

AFR optimum has everything to do with load.