Evidence that long stacks are better?

[Flatline]

There is a lot of talk on the forum about getting the short stack changed for a long one, or vice-a-versa

With a corresponding improvement in performance

Where is the evidence to back up the claims made about performance improvement?

[agentpineapple]

if you can wait a couple of weeks, carlos the spanner monkey is planning on doing a back to back dyno, with two long stacks and then two dr honda copy long stacks, i might ask him if he wouldn't mind doing a third run whilst throwing on the standard set up, i'd pay for the run as its only a tenner. that way you will have a true reading of any differences...
personally i didn't notice a massive difference when going from standard to two long stacks, but then i did eat a big mac meal before riding the bike...

[lloydie]

Not sure wether it will show on a dyno with regards to two long ones but you can feel it when riding

[AMCQ46]

I think Tony did some variations on his last Dyno run.

I plan to do a compare at the midland dyno day between the Dr Honda ones which are teh same length and the standard long short combo

[agentpineapple]

I think Tony did some variations on his last Dyno run.

I plan to do a compare at the midland dyno day between the Dr Honda ones which are teh same length and the standard long short combo

i'll save my tenner then......

[mattycoops43]

"Not sure wether it will show on a dyno with regards to two long ones but you can feel it when riding"

The Dyno never lies! it would show smoother pickup I would have thought.

[Virt]

Well I'm still taking the storm down (well my dad is ._.) to the dyno run in june and that runs long and short if it's any help. Which reminds me, Al. I have money, can you pm me your paypal again please? I've lost it in my sea of messages Still need to pay deposit, oops.

[VTRDark]

Dr Honda ones which are teh same length and the standard long short combo

err are you sure about that. I thought the standard long stacks where longer. In fact I know they are longer. Anyway you can't compare the two as they are a totally different shape. Dr Honda's will have airflow flowing in evenly and faster because of the bellmouth (bevelled) top.

And yes Dyno's can lie. Not everything shows up on a dyno. A dyno gives you a good idea but it's a tool and should be used alongside real world testing on the road. Also don't forget the dyno techs can manipulate things so you walk away with a smile on your face.

If you have standard stacks, stick a long on the front and you will feel the difference as soon as you go for a ride.

(:-})

[AMCQ46]

Sorry Carl, I was a bit brief in my words. What I ment was drhonda trumpets are the same length.....as each other.

[seb421]

GLSR is your man for this he explained it in detail when he was round but I couldn't re explain it anywhere near as good as he could, explained how all the different stacks and lengths work scavenging air, weak points and strong points of set ups, and given his job he knows his eggs

Sent from my GT-I9300 using Tapatalk 2

[AMCQ46]

Seb you are right, the different length Is about pulse tuning which allows you to optimise the resonant frequency of the waves to help them assist you in filling the cylinder. Longer trumpet is suited for lower revs and shorter is better at higher revs, so what Honda has done is to try and get a bit of the best of both worlds but if you only want the mid range fit 2 long and if you want top end fit 2 short.

You should be able to see it onthe dyno as it will change to power curve shape.

[benny hedges]

Not sure wether it will show on a dyno with regards to two long ones but you can feel it when riding

can definately feel it on mine - it runs flat as a pancake lol,.

with the cams i use and mild porting it very much wants to be up between 7k & the limiter all the time - with 2 long or one of each it feels like its got asthma

[Flatline]

But if 2 long stacks give better mid range torque, surely that will show up on the dyno?

[Kev L]

Or you could pay less than the cost of two or three dyno runs and buy yourself an extra set of stacks and try the different combinations for yourself.

[Flatline]

Have done Kev

Now back to normal and not sure if I could tell any difference