DirtRider . Net MX, SX, Arena Cross, Off-Road Community

This is the text version of DirtRider.Net
Click Here for the Full Version

Pages: 1

Sub Tank flow??
(Click here to view the original thread with full colors/images)

Posted by: chrismxer---------------------

I have a set of Enzo sub tanks witch I like very much!!

I have also seen some new style sub tanks that, to mount them you don't have to drill and tap your caps. These also have a check valve that I've read is not as good as the plain metered flow in and out style valves.

So is this small amount of flow sufficient enough for maximum tuning / performance??

If so, does anybody know where to get some fittings to adapt my Enzo tanks right into my new YZ250?? I'm sick of drilling and tapping then having to come up with something to plug up the holes with when I off the bike. I know Enzo sells some plugs for this very reason. But if it's not nessesary then why drill??

Thanks, Chris.

Posted by: Jeremy Wilkey---------------------

Chris,

This is a loaded thread.. All I'm going to say is that the other tanks are a knock off of the orginal, they cannot work properly and anyone who buys them is a sucker for gimics, in the name of a low price.

So after the above statements start a fire I'll come back with a bucket of water and put it out with hard facts.

BR,
Jer

Posted by: chrismxer---------------------

Well.. facts are facts. If there isn't sufficient flow then there isn't.

I know when I run my Enzo set up I open the adjuster very little, no more than 1.5 - 2 turns. Also on my new YZ forks the pressure release hole that runs through the cap at a 90 degree angle is also very small. I havn't tried the sub-tanks on the new KYB's, so I don't know if there are problems with that also??

Lets get this fire started it's a little cold out here!!

Thanks, Chris.

Posted by: marcusgunby---------------------

I tried a homemade setup that was using the std bleed holes, it didnt work-i had to go larger and drill and tap.

Posted by: Jaybird---------------------

I'm not sure if I buy the check valve thing. In one direction of flow, the check valve will require a stated amount of PSI to open the ball and allow flow through the oriface. But in the opposite direction, a check valve will completely restrict the flow.

And air flow is dependent on the pathway it encounters.
The smallest oriface will provide the greatest amount of resistance in the line, and no greater flow can be obtained past what that oriface will allow.
In theory, the flow control valve serves as the restriction point of the line. It should be completely determining the velocity of the air flow by restricting the airflow in a controlled fashion.

If there is a restrictive oriface in front of the flow control valve, the valve can only control the air to a point that the small oriface allows.

In other words, all of the orifaces that the air sees needs to be larger (or allow more flow) than the flow control valve will allow at it's least restrictive position (all the way open). This situation will give complete control of the velocity to the flow control valve...and inversely, a small oriface at the bleed opening could restrict the flow enough to make the flow control valve moot, which means the control of the flow is restricted by the smallest opening (bleed hole..or more specifically the oriface in the fitting used at the bleed hole).

IMspodishO...I think that the optimum situation for these tanks would be to have all the openings large enough to allow the flow control valve to do it's intended job and completley control the flow of air. And the returning air back to the forks should not be restricted at all. It should be a clear free flow back to the forks, and only the air headed to the tanks should be restricted in a controlled fashion.

Posted by: bedell99---------------------

I deal with balancing coils in the HVAC industry all the time. I always thought that these subtank where basically a balance valve with an air chamber.(Basically you use air instead of water) Jay your idea of not having the rebound be affected is imposible with a single valve, especailly with an orifice. You need a bypass and a check valve to allow the rebound circuit to be not affected. If you have 1 valve controlling every thing it will affect the rebound. I agree with though, logic tells you that you only want the subtank to work in the compression stroke. I'm really curious what Jeremy thinks about this and if that is what the enzo subtank do. I always had an idea that if you use 2 tubes coming out of a subtank you could easily control both the compression and rebound, but that would mean 2 taps.

Erik

Posted by: bclapham---------------------

Quote:

Originally Posted by Jeremy Wilkey

Chris,

This is a loaded thread.. All I'm going to say is that the other tanks are a knock off of the orginal, they cannot work properly and anyone who buys them is a sucker for gimics, in the name of a low price.

So after the above statements start a fire I'll come back with a bucket of water and put it out with hard facts.

BR,
Jer

apart from the Enzo, which ones have you tested jeremy?

Posted by: chrismxer---------------------

The check valve debate is interesting. I'm leaning more towards the plain style valve.

If your entering a section with some heavy chop (no check valve) this would give you more of the effect of a lower oil level due to more of the compressed air is still in the tanks. Thats one of the benefits of the sub tanks (lower oil level feel). The rebound issue seams like it could be tuned out with a few ckicks or some minor valving changes. It would seem that in this situation you would be using the medium speeds of the rebound circuit. The clicker adjustment is low speed, but does bleed into the other speed ranges of the circuit.

On jumps I don't think it matters what kind of valve you have because equalization will occur due to length of time in the air.

Eric, the Enzo tanks do not have a check valve.

On the other topic of hole size I'm not totally convinced yet either. Like I said in before, when I had my Enzo set up going I would only open up the adjuster 1.5 - 2 turns. Don't know if others are opening up theirs more or not, but I felt that that was the best range. Is that opening of 1.5 - 2 turns bigger than what the smallest restrictions ID would be on a set up with no drilling?? Marcus Could you elaborate more on your findings. Where did you get these fittings? How big was the ID on them?

Thanks Chris.

Posted by: marcusgunby---------------------

http://www.dirtrider.net/forums3/sh...ghlight=subtank

Posted by: Jeremy Wilkey---------------------

Quote:

Originally Posted by chrismxer

The check valve debate is interesting. I'm leaning more towards the plain style valve.

If you’re entering a section with some heavy chop (no check valve) this would give you more of the effect of a lower oil level due to more of the compressed air is still in the tanks. That’s one of the benefits of the sub tanks (lower oil level feel).

On jumps I don't think it matters what kind of valve you have because equalization will occur due to length of time in the air.

Eric, the Enzo tanks do not have a check valve.

Thanks Chris.

Chris,
Thanks! It’s a buffer, if you want bottoming control only then a check valve or not and it does not matter. But if you want bottoming control for landings and a more linear air spring (less resistance/progression) for bumps then doing a check valve does allow the tank to buffer.

As for a problem with the rebound, its not. We still have a significant positive pressure both in the main fork and in the tank as the fork starts to rebound. If the tank held more volume than the forks then we would have an issue but as it is we are no where near a threshold. (A point where there is no positive pressure in the main fork (relative to atmospheric))

Subtanks generally work better with tighter settings not so much for bottoming control but for breaking bump performance. I never run mine softer than 3 out as that will start to make the pressures equalize too fast, and the braking bump performance will go down, more than bottoming control will be lost. I like larger tanks in all applications. Even in small air volume forks like Showa or KYB TC forks the larger tanks seem to work better than the smaller ones.

So having worked through all these tendencies I can comfortably say I understand, and have experienced how the system works, a check valve system will reduce the effect of the buffer and that’s the main attraction for those of us wanting the best balance of plush while deep in the stroke and bottoming control.

As for the orifice size deal that’s why I think a lot of these check valve tanks work, the restriction is in the hole size so whether we have a check valve or not we have so much drag it does not matter. That’s just an educated guess.

I know the Enzo was the first, the predicted results match the design theory and as we change variables in tuning they match the equation so I'm comfortable with everything.

BR,
Jer

Posted by: MXGOON---------------------

Chris,
With all due respect for Jeremy, I had the same questions a little over two years ago. I had an '03 CRF450 that Jeremy did including Enzo subtanks. I loved the way things worked. But, as with any bike, once you get used to it, you start to notice things that can be better.
I noticed at a local track that I ride at a lot, in a long set of whoops with a steep faced jump at the end, that I would bottom out really hard on the face of that jump. I tried to correct it with adjustments, but had no luck. I started to turn in the adjuster screw on the subtanks to try and fix it. And, finally I got the bottoming problem fixed, I turned off the tanks. But, this led to a harsher ride everywhere else, so I kept going back and forth trying everything. I never got that problem figured out. I noticed the same little problems at a few other tracks, that had a landing followed by a sharp impact. It would seem to blow through what travel was left in the fork. If you have ever broke an air line on a subtank and had to finish the race with oil spraying everywhere. Then, you know what I mean, that feeling of not having an air spring.
Anyway, I got tired of drilling my fork caps too. So, I looked else where. I found a thread on another site talking about drilling or not. So, I did some research on the orifice sizes, and found Enzo's 3AN fittings, that screw into the forkcap have a 3mm I.D. hole. That is why they do not work well all the way open. Because, of the 3mm hole would restrict the CFM more than the valve. I saw a set of FVO tanks from Framebreaker Racing with a no drill system. I emailed them to ask them the same questions that you have asked, Chris. I even emailed Jeremy at MX Tech, and asked him some questions. What I learned was, the FVO no drill set-up has a 2.5mm hole as the smallest orifice size (The forkcap adapter). And, they use a different valve than Enzo with a by-pass circuit that allows a freer flow in return to the forks(Not a check valve). Jeremy told me that kind of system wouldn't work at all.(Keep in mind this was two years ago) But, I kept remembering some of the complaints that I had with the Enzo's, then I decided to give them a shot. Then, the guy's a Framebreaker Racing gave me a set plugs, that restored the forkcaps back to stock so I could try them on my '03 CRF450 and told me that they would give me my money back, if I didn't like them as much as the Enzo's. So, I got them and use the Enzo's back to back with the FVO system.

So, to keep the babbling down, If I were you, I would do more research. Don't just listen to the people selling the products, listen to what you want, and what you know you need, and listen to what others say that have tried them both. Jeremy, I still love your suspension and all of your help. But, I do love my newer set of subtanks too. When I rode with them back to back, I went to my local track to hit that section. The FVO system allowed me to have the valve open at a setting that I liked, (3.5 out of 8) and have plush forks on the entire track. But, I didn't bottom out after the whoops with the FVO's. I did go back a couple of times to make sure. The FVO's are different than the Enzo's, maybe it is the concept of a buffer as Jer put it? But, the quality is the same and I don't have any strange issues any more. I also like the fact that no one can see them unless they look really hard.(Hoses don't stick up) I have been racing for 15 years, and I know what I like and dislike. But, I'm just a local 200lb. "A" rider who loves to ride!

Like Jeremy said, "Be aware of cheap knock-offs trying to make a buck" But, just because it's new, doesn't mean it's cheap or a knock-off, it could be just improved or different. Does that make Honda a cheap knock-off of a Yamaha? Just because they are the original 4 stroke mxer? Different products work differently for some people. Some like Yamaha's I like Honda's, to each his own. So, don't be affraid to shop around and try new things.

Posted by: Jeremy Wilkey---------------------

Goon,
Thanks for the coments, glad you like my setups. You make good points, I agree research should be done by anyone. So great advice and I respect your postion. I on the other hand I don't nesicalry agree as your foucus seems to be diferent than mine on what we want for a outcome. You described a pack and wanted to prevent bottoming, I want a buffer, could be lots of stuff contributing to the overal results althought the results are what they are for you and its cool.

As you pointed out I've leanred alot since we spoke (don't remember when) but I will say I was recomneding too much oil volume even 1 year ago, as I'm now recomneding 340cc or so for none Subtank forks, and 380cc for subtank forks. I'm sure I was in the 400cc range 2 years ago. That will create more effect than what is optimum. So I've learned quite a bite over the years but thats normal.

Jer

Posted by: chrismxer---------------------

Goon, Thanks for the great response!!

I had that problem also on my Enzo tanks. If I hit a steeper than usual jump face hard I could feel it bottom very slightly. I had some pretty stiff single stage valving too!! It happens with the sub tanks more than standard set ups because the jump face is a lower to middle shaft speed type of obsticle. And thats the area where these sub tanks affect the forks.

When I said check valve I ment the same thing you described. I think that bypass you described is a check valve. The pressure getting restricted on the way in but being able to go though the bypass and adjuster on the way out of the tank being only resricted to the ID of the hose and orfice on the fitting.

Glad to see your happy with the new tanks, it gives me hope of not drilling!! Plus they have the features of no oil build up in the tanks, n easy pressure release and with a return policy like that how could you go wrong! I know it's really no big deal to do all the tank maintenance but when you have plenty of other stuff to do it's just one less thing.

Jer I also agree with you on the oil levels. I first purchased these Enzo tanks from a MX-tech Sa (I think thats what you call them) in northern CA. He told me way to high of oil level (450cc) and 3.5-4.5 turns out on the adjuster. I almost gave up on the tanks. I finally put them back on on another bike with some more ideas to try and came to that conclusion.

Again thanks for the replys, Chris.

Posted by: GaryKTM200---------------------

any body checked ou the AIR CELL design??? dirtriders product of the year. what is your opinons?

Posted by: chrismxer---------------------

Thats pretty much one of the few that I was refering to other than fitting my Enzo tanks with a fitting that required no drilling.

Posted by: MXGOON---------------------

I think that is what Jer was saying about a cheap knock off. You can build those tanks yourself for about $100 and a McMaster Carr catalogue. But, what the heck? They might work? For the money I would go with the Enzo's or the FVO System! Those are my two favorites. I have tried Too-Tech's and even Tech-Care's neither one of them work as good, or are as good looking as the Enzo's or the FVO Systems, you really can't go wrong with either one of them. Like Jeremy said, it comes down to what you want and what works for you.

Posted by: bedell99---------------------

This is more of general question regarding subtanks. Is it neccessary to revalve when installing subtanks or can clickers jsut be adjusted??

Erik

Posted by: Rcannon---------------------

I know everyone is different, but my bike needed a revalve to be correct with subtanks...not that subtanks hurt the fork...they did not.

Bad valving is bad with a subtank or without one. If you asking about a Yamaha , chances are your valving could be improved.

Posted by: mx_361---------------------

Hey chrismxer, I have the the FVO tanks now and they work great without drilling. Nothing cheap or knock off about them. I have had the Enzo tanks and they are great too but I got tired of giving them up when it was time to sell the bike and I was always uneasy about taking a drill to my forks. You have the love the carbon fiber on either! Very trick looking set up and functional.

Posted by: chrismxer---------------------

Thanks mx 361, I'm thinking of trying those FVO tanks and selling my Enzos on Egay. That way I can also transfer them to my off road bike when I hit the trails in the rainy season. I talked to the guy who makes them and he seemed really knowlegable.

Thanks, Chris.

Posted by: Jim Havins---------------------

Jer:
What kind of oil volume are you recommending on the newer Kayaba forks (05 yz250) with the Enzo's ?

Posted by: MXGOON---------------------

Chrismxer,
I swap my FVO's from my bike to friends bikes so they can try them out all of the time. It takes about 3-4 minutes to swap from bike to bike! Can't do that with my Enzo's.

Posted by: Pete Payne---------------------

I will just say this . It is hard to out do the original !!! Sometimes a little extra work goes a long way !!!!

Posted by: MXGOON---------------------

Well Pete, I will gladly trade you any one of my two enzo systems for a fvo system. Yeah, it's that good! I've been using enzo's for four years, and this past year I've been using both the enzo's and one fvo set up. Next year will be all fvo's on my bikes.

Posted by: chrismxer---------------------

I have the FVO's on order and will report back. Jason at framebreakerracing.com who makes the tanks is very knowledable and helpful.
He is also sending me some plugs so I can do some back to back testing.

Posted by: Pete Payne---------------------

The sub tanks seem to make a little less dramatic affect on twin chamber froks than the older cartridge units .

Posted by: MXGOON---------------------

That is very true. It's because now they are not eliminating the oil cavitation that the tanks were originally designed for, the twin chamber design did that. We are not using the subtank for which it was originally intended. But, they do help in alot of other ways as Jeremy pointed out, kind of a happy accident. And having a way to basically tune the affect of oil height, that has a speed sensitive self adjustment all in one.

Text Version Home

This is the text version of DirtRider.Net Click Here for the Full Version

Sub Tank flow??

This is the text version of DirtRider.Net
Click Here for the Full Version