Smaller Header Pipes

**WINJA** · 3rd July 2005, 21:23

Originally Posted by marty

i think he meant that it was as volumetrically efficient as it was going to get, therefore it was, for all intents, operating at 100% of its ability.

I MEAN THAT CAUSE OF THE ENGINE SPEED AND CAM TIMING IN CONJUNCTION WITH THE EXHAUST AND INLET SHAPE THE CYLINDER CHARGE AT HIGH RPM IS SLIGHTLY HIGHER THAN ATMOSPHERIC PREASURE , IE HIGHER THAN 14.7PSI ABS OR 101KPA ABS.
THIS EQUATES TO A SLIGHT SUPERCHARGING EFFECT

**Coyote** · 3rd July 2005, 21:28

Originally Posted by WINJA

IF PEOPLE LIKE 2 BROTHERS ARE FUCKING UP EXHAUSTS ON 250S YOU HAVE NO
CHANCE.

You're doubting my abilities? Think I'm gonna cry now (sob)

Even if I have no hope of improving the performance it'll still be fun to give it a go. I haven't got anything to lose as I'm not going to cut up my original headers of course

**WINJA** · 3rd July 2005, 21:30

Originally Posted by alarumba

You're doubting my abilities? Think I'm gonna cry now (sob)

Even if I have no hope of improving the performance it'll still be fun to give it a go. I haven't got anything to lose as I'm not going to cut up my original headers of course

WELL DO IT THEN IF YOU WANT TO WASTE YOUR TIME DOING THAT SHIT INSTEAD OF HELPING WINJA PAINT HIS ROOF

**The Preacher** · 3rd July 2005, 21:32

As "Vance and Hines" say, alter the exhaust then you must re jet the carbs to gain the benefits or you will be worse off.

**Coyote** · 3rd July 2005, 21:39

Originally Posted by WINJA

WELL DO IT THEN IF YOU WANT TO WASTE YOUR TIME DOING THAT SHIT INSTEAD OF HELPING WINJA PAINT HIS ROOF

If I did make them in metalwork, all it would require is bending a few pipes. Easy NCEA credits

**WINJA** · 3rd July 2005, 21:40

Originally Posted by DarkOne

As "Vance and Hines" say, alter the exhaust then you must re jet the carbs to gain the benefits or you will be worse off.

AND AN OLD AKRAPOVIC INSTRUCTION BOOK SAYS VANCE AND HINES ARE WRONG YOU CAN GET A PERFORMANCE GAIN ACROSS MOST OF THE RANGE BY BOLTING ON A AKRAPOVIC WITH NO OTHER CHANGES, AFTER TRYING ARROW , VANCE AND HINES AND AKRAPOVIC ON THE SAME RACE/ROAD BIKE ID HAVE TO SAY AKRAPOVIC ARE THE MASTERS OF PERFORMANCE EXHAUSTS.
VANCE AND HINES IS A HAS BEEN COMPANY

**RiderInBlack** · 3rd July 2005, 22:18

A lot of famous inventors have been told by "Experts" that they couldn't achive what they were trying to achive. Thank God they didn't let that stop them from trying anyway.

My advice is listen to the advice you are given, but don't let that stop you from trying. At the very worst is that you will learn by practical experience why the "Experts" are right. At the best you will come up with a new (maybe better) way of doing or makeing something.

Go for it

**pete376403** · 3rd July 2005, 22:32

Agree with RiB, but remember Honda have forgotten more about tuning that the aftermarket pipe makers will ever know.
Also agree with WINJA about +100% VE - it can be done but the trade off will be a very narrow power band and crap performance outside of this range. The old British race singles were a good example of this - "megaphonitis" was the word used to describe it - or the old piston ported two strokes with expansion chambers and a razor thin power band.

**HDTboy** · 3rd July 2005, 22:36

CBR250s like mine and alurumbas make max torque at 11'500, and max power at 15'000 indicating a relatively narrow powerband, and I'm still supporting the theory of +100% VE.
I don't think you'll improve anything alurumba, but I'm interested in seeing what results you do get

**NordieBoy** · 3rd July 2005, 22:44

Originally Posted by HDTboy

CBR250s like mine and alurumbas make max torque at 11'500, and max power at 15'000 indicating a relatively narrow powerband, and I'm still supporting the theory of +100% VE.
I don't think you'll improve anything alurumba, but I'm interested in seeing what results you do get

Sounds like they're a little too free-flowing.
A bit more back-pressure (smaller headers/exhaust) may help move the peak down the rev-range or help broaden it out.
You'll notice less power on top but you may just get there quicker

Give it a go alurumba

Oh and how much do you mean by "smaller"?
What diameter are the originals?

**HDTboy** · 3rd July 2005, 22:52

Most of the time you have at least 8000 revs aboard anyway, it's a different riding style. To get the most benefit, one would need to change cams, and the fuel and ignition curves

**WINJA** · 4th July 2005, 10:33

HAVE YOU GUYS SEEN THE MICRON HYDRATECH HEADERS, IT MUST BE A GREAT IDEA COS HONDA HAVE COPIED IT

**SPORK** · 4th July 2005, 19:25

Wouldn't it just be a better idea cleaning out the old smelly header pipes, polishing them or soemthing so that the gasses can flow freer? That seems to be the best idea I think, that way you get OEM headers with improved flow.

But I'm probably wrong. Time to go paint Winja's roof.

**WINJA** · 4th July 2005, 20:13

Originally Posted by Spleen

Wouldn't it just be a better idea cleaning out the old smelly header pipes, polishing them or soemthing so that the gasses can flow freer? That seems to be the best idea I think, that way you get OEM headers with improved flow.

But I'm probably wrong. Time to go paint Winja's roof.

YAY PAINT MY ROOF