Short Stacks, I did these today !

I added these short velocity stacks, -30mm from standard. I noted that the 6th gen has 2 shorter stacks that take peak torque to 8750rpm from 8500rpm on the 5th gen !







Lots of stack calculations later show that -30mm should push peak torque to around 9750rpm, which should boost the HP figure too. Only time will tell, but I took it for a quick 10 mile test ride & everything works & the induction roar under heavy throttle openings is louder than before

Hope to get it on a dyno to prove the theory soon !

Enjoy

 

Hey that's pretty cool. When I think of velocity stacks I think of 8 chrome horns coming through the hood of something completely awesome. Bravo good sir, bravo.

 

i take your factory short stacks and "raise" you R6 stacks and port matched throttle bodies

http://vfrworld.com/forums/mechanics-garage/40849-stage-3-air-box-mods.html

 

How many pony gain? op2:

 

trap speed went up about 4 mph. no dyno work yet. i have a lot of other things going on and the fueling is pretty good as is. ill get to it eventually though.

 

I hope that was done off the bike ! Where did all those alloy shavings go ?

You want longer stacks for drag racing as you need Torque, I wanted shorter stacks as I want HP. I will get the bike dynoed & see if the theory is matched in reality with a higher peak torque RPM. If yes, then I will machine the throttle bodies to match the new stacks !

 

lol why would i want longer stacks for drag racing?

 

Well if you could run an acceleration profile, you would find that there is more acceleration at low speed & less as speed increases due to drag. So longer stacks make torque lower in the rev range & thus increase the low speed rate of acceleration, which all makes for easier launches etc. Do a search for CBR1000RR v Old Harley rat bike, the Harley destroys the CBR for acceleration from a standstill, due to the difference in the way both bikes make power. You need torque to accelerate & HP for max top speed.

Where did those alloy filings go again ?

 

Lol have you ever drag raced before?
What you are saying would make sense if you launched at 2000 RPMs and had factory gearing and widely spaced gearing, but launching at high RPMs, with a sprocket kit and a close ratio gear box, what you are saying holds no value.

 

so where did your 6th gen get a close ratio box ? High rpm lose you drive with clutch slip & wheelie control issues.
Still don't know where those alloy filings went ! you must be crazy to do that whilst fitted to the bike, but hey it's your bike & your money.

 

if i roll the throttle open any where in first gear it stands up. even lowered and with fork straps, you have to roll the throttle open at a very controlled rate to keep the front end down. more low end torque is the last thing i need. when i shift into second i am at 9000 rpms, i am no where near falling out of the power band. i really feel like all these ideas you are coming up with may work on paper, but in real life at the drag strip this all far from true. if you ever go to the drag strip you will see what i am talking about. acceleration is a direct factor of hp and weight, and not directly related to torque. horsepower = torque*rpm/5250.

 

Here see for yourself. you could have 1000 ft/lbs of torque or five. it doesnt matter. all that matters is the rpm that you make it at ,ie horsepower and your ability to stay in that rpm range, ie gearing and launch rpms.

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