Calling all people knowledgable on N/A.. carbs.. bodies etc

**Leeds_finest** · Thursday 26th January 2012, 17:55

Following on from last post regarding camshafts, just wondered if anyone has any knowledge or experience of trumpets and velocity stacks on carburettors or throttle bodies?

I was reading that you can literally alter the power band and characteristics with the overall length and the flared end of the trumpet!

I think it's crazy how something so minor in terms of detail could completely alter the way the car produces it's power etc.

Anyone have any experience or thoughts?

Interesting read:

http://www.emeraldm3d.com/articles/e...th-intake.html

Ed

**dalhousie2008** · Thursday 26th January 2012, 18:01

Don't forget that the inlet manifold length also has a big difference in how the carbs perform. Ive done a bit years ago with carbs on bikes and when i used to put cbr900r fireblade carbs on 2 litre pinto engines for kit cars, but the best thing to do would be look via bike tuning route.

I had very good book for tuning 2 strokes, ill see if i can dig it out.

**Jamest5r** · Thursday 26th January 2012, 18:06

Yeah there was an article in PPC mag a couple of months ago about them, you want for the polo?.

**Leeds_finest** · Thursday 26th January 2012, 19:52

Originally Posted by dalhousie2008

Don't forget that the inlet manifold length also has a big difference in how the carbs perform. Ive done a bit years ago with carbs on bikes and when i used to put cbr900r fireblade carbs on 2 litre pinto engines for kit cars, but the best thing to do would be look via bike tuning route.

I had very good book for tuning 2 strokes, ill see if i can dig it out.

Cheers mate. Well i'm running Yamaha R6 carbs on my 1,600 single cam 8v engine. The inlet manifold was made by Bogg Bros who seem to know their stuff, so i'm guessing my inlet manifold length is ok, about 3-4 inches I think, does that sound right?

Originally Posted by Jamest5r

Yeah there was an article in PPC mag a couple of months ago about them, you want for the polo?.

Yes mate. Basically, my problem is, I have to rev it really hard to get the power from the engine. This is MAINLY due to my cam, it's too lairy, so will be changing to milder cam and going higher with the compression.

However, according to that article above, the rollers seem to prove that longer trumpets actually help to bring peak power down the rev range, which is what I need, as well as improving peak torque and bringing that further down the revs too - amazing what a trumpet length can do!

**dalhousie2008** · Thursday 26th January 2012, 20:52

Try a chap called Philip joy, I know him reasonably well. What he doesn't know isn't worth knowing. Kent cams go to him with there problems.

Joy engineering in bishops stortford, I won't give you his moby but main number is in google.

He's usually quite happy to chat, makes bespoke camshafts from scratch

**Leeds_finest** · Friday 27th January 2012, 00:43

Originally Posted by dalhousie2008

Try a chap called Philip joy, I know him reasonably well. What he doesn't know isn't worth knowing. Kent cams go to him with there problems.

Joy engineering in bishops stortford, I won't give you his moby but main number is in google.

He's usually quite happy to chat, makes bespoke camshafts from scratch

I'll give him a shout, who should I say mentioned him?

**dalhousie2008** · Friday 27th January 2012, 07:33

He made me some camshaft for one of my xr200 a while back, but he had a big spread in practical classic motor cycle.

But try him he really is the best.