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Adrenaline Junky
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Discussion Starter #1 (Edited)
A couple of people are looking at doing this mod atm so I decided to do a quick write up on how I installed the TLR velocity stacks in my TLS airbox.

Stu has done some testing and reports that there is a 7% improvement in airflow.

Parts needed: One stock TLS airbox, pair of TLR velocity stacks, 6 x M8x15 allen headed bolts.

Tools needed: Medium phillips screwdriver, 4mm, 6mm, 8mm drill bits, drill, 8mm tap & 6mm allen key.

Start by dismantling the airbox, remove the filter and the rubbers until you are left with this




now assemble the pieces you need. From left to right: TLR velocity stack, velocity stack washer, TLS outlet rubber.





Now you can throw away the velocity stack washer, this wont be needed anymore. You need to separate the TLS outlet rubber from its clamp and then put the TLS outlet rubber back into the hole, but this time from the inside so that it looks like this:



The rubber makes sure that the velocity stack is centrally located in the hole when you put it in (from the outside) like this




Now that you have the velocity stack in position mark the centre point of the three holes with a pen, remove the velocity stack and the TLS rubber then carefully drill them through starting with the 4mm bit, then increasing to the 6mm then 8mm bits.




You need to put the TLS rubber back in its correct position thus




Now comes the time to mod the velocity stacks themselves. On a TLR the velocity stacks attach to the throttle bodies through the airbox anchoring it in place. One possibility would be to use a nut and bolt and spend hours of contorting and swearing trying to get them to match up and meet up, but after considering this i decided to opt for a simpler way. Using the 8mm tap you need to cut a thread into the three holes on the ring of the velocity stacks. As you can see in the pic its less painful to wrap the velocity stack in rag if you're planning on doing this without the aid of a vice.




a few minutes work and you have the finished velocity stacks




now you insert the velocity stacks into the opening from the inside, gently wriggling it to that the holes line up with those you have drilled in the airbox. Once they are in place you can then start bolting them down with the M8x15. Its easiest to just get each one to bite and then go round tightening them each by one turn at a time so the stacks slide smoothly into their final position. Then reposition the rubber clamp.



Repeat with the second one and then you are done :thumbup


Some photos from inside the airbox and finally with it positioned back on the TBs.










Only things I would do differently is to get the velocity stacks ultrasonically cleaned first, and to have had a shorter set of M8 bolts to they don't protrude so far into the airbox. I'm hoping that as they are they wont interfere with the airflow. Remember that you will need a Power Commander and a custom map if you do this mod.

Hope this helps others!
 

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Thanks for the great write up.

Very interesting!

Are there any dyno tests with this mod?

Keep an eye on the post for the bung in the next couple of weeks!
 

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Not sure in my own mind as to how the efficiency is determined. I understand the concept of lamina flow etc but I'm also aware that the dimensions of the venturi are critical in terms of gains. Are we saying that the PC used in conjunction with a dyno will sort out the dynamics given the parameters. Very interested in seeing this worked through to conclusion ... it certainly looks like a nice little project to have a go at.
 

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Adrenaline Junky
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Discussion Starter #4
Its going to be April before this bike sees a dyno. Whilst its in pieces i decided to work on the airbox, cut out the actuator and flapper to improve volume into the airbox, and originally the idea of the velocity stacks was as a fail safe in case oil gets to the airbox, but then with further research it proves to have a noticeable performance gain too.

My main goal for the build of this bike is to have the best handling TL possible and there will be a build thread on it soon, im still amassing parts. I am not a good enough rider to get the most out of a stock engine anyway, but I am good enough to be hindered by the handling. First things to change: suspension and braking. If I ever reach the limits of this bike the i will look at upping performance. Even a stock TL is capable of embarrassing modern sports bikes...

theres a link in the top post to Stus flow tests.
 

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Mine already has velocity stacks, just push them into the top of the throttle body from inside the air box. They fit without having to bolt them in. :O
 

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I would love to be able to compare this to the stock TLS setup, could you please add a pic or two comparing the TLS versus TLR velocity stacks? Size/length etc.

I can remember what the TLR velocity stack is like, but I can't even remember what the stock TLS velocity stack is like...is there even one (I mean two LOL)?
 

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Adrenaline Junky
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Discussion Starter #8
There isn't a TLS velocity stack :p Stu has some testing (see link in top post) as to the benefits in airflow by running the stacks in the TLS airbox.

You can just push them in, but Id much rather know that there is no risk of movement by bolting them in place. Ive just finished fibre glassing the airbox now, so I will take some pics and post them up tomorrow.
 

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^^^ Yeah but Chris your bike has been in bits / off the road for about 4 or the 5 years :) :)
 

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It's been used every year Nic, it's never in pieces. The occasional thing breaks but never needs to be in pieces

Fact is, if there is any benefit to fitting tlr velocity stacks in there there isnt any need to bolt them in. They fit perfectly well and snug, why create more bolts to undo everytime you want the airbox off. :O
 
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