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[HammyUK]

PB also fitted completely different cams Andy.

[slapknacker]

yes but the cams were done after the the secondaries were removed.
think first mod was pc111, second mod secondaries out, third cam regrind etc.

pb also did it a while back 2yrs or so on a zx14r when Dale was doing the cannon ball run.
they got good gains low down.

so there results show an improvement. they also did it on a gixer750 that they big banged.

we all know they are there to allow the engine to breath at the correct rate at lower rpm levels
with a wide open throttle, remember cv carbs and flat slides.
stops the motor bogging down until the induction velocites have increased with engine rpm.

[HammyUK]

The zzr benefitted because of the emissions programming strangling the motor.
The butterflies work because they effectively make the throttle bodies smaller and increase the speed that the gas flows at.

[slapknacker]

exactly, the venturi effect

[HammyUK]

It still amazes me how many people just take as gospel what goes about.
Same with the exhaust valve - mine made 3bhp and 8ftlb more with it connected.

[drewk8]

does it really matter for road use? my 08 was more than quick enough for me with just a growler fitted.. 


boy... i miss her

[FLuke]

[FLuke]

It still amazes me how many people just take as gospel what goes about.
Same with the exhaust valve - mine made 3bhp and 8ftlb more with it connected.

sounds better with it open though 

[slapknacker]

suppose if you race take them out, also the bar which they mount to and get the holes welded up.

road use and occasional track day , leave alone.

sure it sounds nicer with them out, but the extra 'go' you feel may be initial jolt forwards when you
open the throttle as the engine gets more air for a split second.

[r1ninja]

.

It still amazes me how many people just take as gospel what goes about.
Same with the exhaust valve - mine made 3bhp and 8ftlb more with it connected.

Made 3bhp more where in the rev range? No race exhaust manufacturer fits them to their system, they are mainly about noise emissions. 

The butterflies work because they effectively make the throttle bodies smaller and increase the speed that the gas flows at.

Yep that's what primary butterflies are for  

[HammyUK]

Sounds the same as mine has benn de-catted anyway.
Had 3bhp  at the top end Andy and over 5bhp throug the midrange - the hole it left in the midrange disconnected was HUGE.

[r1ninja]

That's at odds with the Suzuki sytem then, they all make more power with the exhaust valve disconnected. Strange that it made more top end power then as at high revs the exhaust valve is fully open .

[HammyUK]

Not sure why Andy - I just remember standing there at RJS while Rob tried all the combinations.

[FLuke]

put secondaries back in today and put map back how it was... fuel economy seemed to die (not that I care much but it was drinking the stuff) and also 1st gear from lights felt hard work

[stevejones1874]

put secondaries back in today and put map back how it was... fuel economy seemed to die (not that I care much but it was drinking the stuff) and also 1st gear from lights felt hard work

I had heard if you put them back in you need to loctite the screws.  If they come loose you will be in big trouble.  Not sure how you do it and whether i'm 100% right.  Thought i'd better mention it.