Velocity Stacks

if these really added any kind of airflow to the engine you would have to tune to see the gains.

every post ive read anywhere on these they didnt change the af any.
 
so no results on a drag bike with these?

Glenn Henderson, Australia at his local track.
+ 1.5 to 2 mph from stock stacks - all stock engine, Yosh exhaust.
Shifting at 10.3 k
He understood optimal shift points. Some was the stacks and some was getting the right shift points. Originally he was shifting right below the rev limit with stock stacks.

M
 
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if these really added any kind of airflow to the engine you would have to tune to see the gains.

every post ive read anywhere on these they didnt change the af any.

Back to school -
Read the links I posted above describing how stacks work on an IR engine.
If you still have questions after reading both, I'll be happy to answer them.

BTW - our stacks do change the mixture on some bikes - the old Busa just didn't change the mixture enough to make me need to change it to get a hp gain from.

If I don't change it, and still get good results, then I can say that I didn't change mixture

M
 
so out of all those people none of them gave you a drag test result?
Already answered

the edit i did was to go by your site. i was looking at another one of your ads and realized it wasn't your site. it said 6-8 hp on a stock gen 2.

6 to 8 mid and upper mid when measured under load of a Hen 1.
Done it many times - on many different bikes.
And riders notice it. Heck we are next to the highway onramp and you can even hear it when the guys leave the shop. It's crisper and sharper (which is what a properly tuned intake tract sounds like.)

Testing becomes more consistent and hp changes become more realistic when dyno testing is dome with enough load - things that work really work show up and things, like short gsxr1000 stacks drop a couple in the low and mid and gain a couple on top (not what a dj dyno says + 6 hp).

It's painful to watch people spend money on things that work on a dynojet - but don't work in the real world and discard things that work in the real world, but don''t work on a dynojet.

M
 
Hey - Here's a link to our website - there's a dynojet dyno chart on it that actually backs up my testing (wonders never cease!) -

So what is wrong with Rowe's / Lee's Cycle tuning or testing or ???
http://www.factorypro.com/Prod_Pages/prods89.html

dynojet dyno
DC_Suzuki,Busa,stacks,dj_dyno.gif


and ours in True HP Scale (True x 1.2 - Dynojet HP)
dynochart_vstacks,S89,yoshimuraexh%20and%2070%20stacks.jpg
 
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An engine's internal heat factor greatly affects power developed, especially after the power peak - and all of this point of view is from engine testing with insufficient loading (and therefore - heat).

When we did make 3 (read as inexpensive) inertia dynes, they had ~2 times the loading as dj and they actually read better - meaning: what worked best on them was closer to what worked in the real world.

We found out many years ago how far off our AMA 750 Supersport bikes were when they worked best on a dynojet style dyno - When you are racing AMA, it's not yacking about poor dyno testing, it's where the rubber really meets the road.
On our good days, our 600's and 750's were trapping the same top speeds as the Yosh bikes - Ask Scott Link. if he still works at Lee's. (well, ok, not when they were using the close ratio gearboxes and the 13,999 rpm ECU's).

If I wasn't right, Jordan Racing wouldn't have had the quickest Superbikes at Daytona - they'd still be befuddled with a dyno that "told them something was better" when it wasn't better in the real world).
 
That's pretty funny.
It was funnier before you edited it. <wink!>

But that information is probably from the same sort of dyno that said short Suzuki stacks were worth 6 hp.
Otherwise you wouldn't think that you couldn't manage to get 3-5 hp on something.

Come on now -
We've made stacks for World Supersport 600 teams, stacks that have gone on ZX14 and gsxr1000 land speed record holders, World Endurance Teams, Jordan Suzuki, Vesrah Suzuki, Motorcyclist and Sportrider project bikes, Erion Honda bikes, and loads of other teams and bikes - there was even a set on Doug Chandler's Zx10 streetbike. Even Ryan Schnitz tested them.

If all these guys think that they work, how am I supposed to take some guy's funky dynojet charts done at a local shop? :-)

Marc

Wow, I still have to wonder where you have been all these years Marc to suddenly come on the scene and start calling peoples dyno results "funky". Last I checked there are 204 Dynojet tuning centers in California alone and you have only sold 39 EC997's in the entire United States with none in California (according to your website). Personally I think everyone has an opinion and they are usually worth what you pay for them. In my case it cost me a couple of hundred $$'s for some really pretty velocity stacks that did nothing for my performance. I have no doubt that you are a very educated and skilled individual but I think that there are any number of people in the country that can claim equal results without spending the big $$'s. Personally, it still sounds like snake oil to me and I'm not buying it....no matter how hard you try to sell it. :poke:

PS
Please be advised...it's Dennis to my friends and MR. ROWE to everyone else so if you are going to bandy my name around be sure to show the proper respect.
 
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Wow, I still have to wonder where you have been all these years Marc to suddenly come on the scene and start calling peoples dyno results "funky". Last I checked there are 204 Dynojet tuning centers in California alone and you have only sold 39 EC997's in the entire United States. Personally I think everyone has an opinion and they are usually worth what you pay for them. In my case it cost me a couple of hundred $$'s for some really pretty velocity stacks that did nothing for my performance. I have no doubt that you are a very educated and skilled individual but I think that there are any number of people in the country that can claim equal results without spending the big $$'s. Personally, it still sounds like snake oil to me and I'm not buying it....no matter how hard you try to sell it. :poke:

so he sales the dyno's too.. :lol:

im with you. snake oil. :beerchug:
 
Wow, I still have to wonder where you have been all these years Marc to suddenly come on the scene and start calling peoples dyno results "funky". Last I checked there are 204 Dynojet tuning centers in California alone and you have only sold 39 EC997's in the entire United States with none in California (according to your website). Personally I think everyone has an opinion and they are usually worth what you pay for them. In my case it cost me a couple of hundred $$'s for some really pretty velocity stacks that did nothing for my performance. I have no doubt that you are a very educated and skilled individual but I think that there are any number of people in the country that can claim equal results without spending the big $$'s. Personally, it still sounds like snake oil to me and I'm not buying it....no matter how hard you try to sell it. :poke:

No need to wonder where we've been - for better or worse, posts live on forever.......

You don't have to agree with me or the other people who used the Gen 1 stacks and got good results - that something is very curious about the both dismal and overly optimistic Lee's dyno tests.

On the other hand, I and the other guys don't have to just accept that the tests you've posted multiple times in multiple places, are pertinent to the real world.

It's your opinion that your testing was valid and my opinion that something was funky about the tests - I supply my testing (ok, you can call that an opinion) and even supply an unsolicited dynojet test that someone sent me when you first posted your charts that backs up my "opinion" that the Lee's test or bike or ? was likely, well, "funky".

Somebody who you consider qualified, do the tests - and got extremely out of scale results.
I generally consider Lee's to be reputable, too.

I would find it surprising if a lot of people found 6 hp with short suzuki stacks, even on a dynojet.
So if the "+ 6 hp" is funkily optimistic, why would anybody believe the 6 hp loss with our stacks on a stock cammed bike?

As far as number of dynos sold - I kinda sell dynos to people who know tuning and know about dyno testing. Most of the guys who buy EC997 dynos have already owned, leased or used dynojet dynos previously and know about loading and EGA use.

Our website doesn't say that we've sold "39". It's more like maybe 39 places want to pay to be listed for contact info?

I don't do a good job selling dynos to people who don't know much about engines and tuning. There are other dyno companies who are 20x better at that than we are.

As far as the Lee's dyno test on your Gen 1 bike (posted in a Gen 2 forum), my opinion is that something was funky in the testing (because of the both overly optimistic and overly dismal results) and your opinion is that you are 100% sure that it's not funky, (because your bike got 6 hp from the short stacks).

That just about sum it up?

Thanks,

Marc
 
so he sales the dyno's too.. :lol:

im with you. snake oil. :beerchug:

Yes, Matt - we design and sell high speed, realtime readout, low inertia, eddy current brake dyne systems, build 4 and 5 gas EGA systems and have 6 dynamometer and engine tuning patents.

The dyne systems are capable of providing a wide range of test loading conditions, ranging from something emulating a dynojet test to controlled rate sweeps to auto incrementing Steady State tests.

The 4 and 5 gas EGA Systems are among the quickest reading systems available and are designed for continuous duty for engine tuning.

Did you have a technical question about how dynos or engines work?

Best regards -

Marc
 
Yes, I have provided my dyno results and opinion to those that have asked questions about velocity stacks and posted them on this and other boards and gee yes I did post on a Gen2 forum...my bad! I would consider your test results on your dyno suspect just as I found the performance of your velocity stacks lacking and people are free to believe whatever they want.... just about sum it up? It is always refreshing to run into someone who says they have the only true path to enlightenment. ???
 
Yes, I have provided my dyno results and opinion to those that have asked questions about velocity stacks and posted them on this and other boards and gee yes I did post on a Gen2 forum...my bad! I would consider your test results on your dyno suspect just as I found the performance of your velocity stacks lacking and people are free to believe whatever they want.... just about sum it up? It is always refreshing to run into someone who says they have the only true path to enlightenment. ???

and sale it too.:lol:
 
Yes, I have provided my dyno results and opinion to those that have asked questions about velocity stacks and posted them on this and other boards and gee yes I did post on a Gen2 forum...my bad! I would consider your test results on your dyno suspect just as I found the performance of your velocity stacks lacking and people are free to believe whatever they want.... just about sum it up? It is always refreshing to run into someone who says they have the only true path to enlightenment. ???

Thanks -

Marc
 
Looks like those stacks fell on their face at 10K. Umm, aren't we on a Gen II site. My shift point is 11,620 (actual) and I'm reading we should be shifting mid-10s. :rofl: When I first saw pics of these stacks I thought they were a joke just based on the absurdly long intake length. While there is merit to obtaining maximum usable power under the curve, that whole argument breaks down if your always above 9.5k. Get this crap off the Gen II site were its only going to confuse people looking for real information.

BTW, many of us on this site are engineers, and racers, and have significant experience tuning and running various types of dynos. This whole smoke show about eddy current vs. inertial is completely irrelevent.
 
My dyno run w/ stacks

Factory Pro stacks in 55mm height went onto my bike the day they arrived, then the bike onto the dyno. Here's before and after.

Peak power(s) didn't rise significantly, but they did rise, not fall; and power rose a worthwhile amount IMHO across the range.

Throttle response became much crisper. Didn't notice any change in sound quality.

This bike is equipped with twin Yoshi slipons, and both Power Commanders; and was tuned on the dyno for the stacks.

aScanned at 12-04-2010 10-50 AM (2).jpg
 
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