DirtBike 11 pipe test=BOLLOX!

5 replies to this topic
  • Matt_Porritt

Posted June 14, 2000 - 09:55 PM


Everyone seen the 11 pipe shootout in July DirtBike?
What a load of S H I T!!

I've been at a dyno when a stock 426 was tested and after 3 runs the hp output at the rear wheel was 44.5-45.5.
Also talking to Phil Tomlin yesterday and he said the stock was 45-45.5hp.
Phil Tomlins test with a DSP pipe and Carbon Airbox was just over 50hp on a 426.
With an E-Series Pro-Mega pipe I've seen a YZ400 poke out 46.5.hp.
They say a stock 426 is 50hp!!!

What is it with these Yank mags??
They're saying that no pipe produces more hp than the stocker.. some LOSE up to 5 on the stocker... yet when you ride them the bike is noticably quicker in parts of the revrange..
According to them there is no pipe that improves topend... utter CRAP!

Shows you how much money they recieve from Yamaha to support stock components... either that or all the aftermarket pipe don't 'work' until they are under load on a MX track.

Grrrrrrrrrrrrr!! :)

**Ride it like you Stole it!**
Matt Porritt
99 YZ400F
Rubber Chicken Racing

  • Mitch_from_Oz

Posted June 14, 2000 - 10:12 PM


Matt, I completely agree with you.

  • Kevin_in_New_Hampshire

Posted June 15, 2000 - 03:23 AM


I do not disagree with you at all. I think payola (spelling?) is alive and well everywhere. However, I have seen identical bikes on different (manufacturer) dynos put out different horsepower/torque numbers. I put a different pipe, DG, on my old YZ250. The bottom and midrange were smoother, but I did lose some off the top. That was OK. That is what I wanted.

99 WR, all YZ mods, de-octopused, OEM YZ tank and seat, jetting by Clark.

Moab bound for 2000, HOORAY!! Gonna be kicking some Moab Ass (Mule or Donkey?)!

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  • Moto-Mike

Posted June 15, 2000 - 08:24 AM


First of all I have not read the article by Dirt Bike yet. In general I feel the dirt bike mags generally over rate after market
products rather than endorse stock equipment.
Yamaha is still going to sell bikes (and advertise)regardless of what an article says about their stock exhaust componets. I've bought several after market exhausts that I felt did'nt improve the performance of the stock componets-contrary to what I read. If Dirt Bike or any other magazine want to endorse stock parts - great that just helps me make an informed decision on weather or not I really need to spend my hard earned money.

  • Matt_Porritt

Posted June 15, 2000 - 04:01 PM


Yeah.. every dyno WILL read different (also other variables as in temp, humidity etc).. but how can they test 11 pipes and give a result that NONE improves topend.. where 'others' can do it and get COMPLETELY different results..

The whole test was Bollox!
They really needed the torque readings of the pipes also..
Hp is ok ok a 2st pipe test as there is not alot of torque but wih a 4st engine there is a HEAP of torque.
I feel the the torque curves of all the pipes will show the differences as the hp readings were a waste of magazine space.

**Ride it like you Stole it!**
Matt Porritt
99 YZ400F
Rubber Chicken Racing

  • MotoGreg

Posted June 15, 2000 - 08:49 PM


Actually they shouldn't have shown the HP numbers, just show the graph with the rpm scale but not the HP scale. The HP number will differ greatly on Dynojet dynos, you can adjust the correction factor on them to get any reading you want. The number isn't important, it's how the graphs compare to each other.

As far as all the pipes making more in the midrange, that's fine with me. I've tried a 426 pipe and it sucked big time, ya it had a killer top end hit if you had a long enough straight to rev it that high but I only had one such straight on the track I was on. The e-series I used to use had a great midrange and would torque hard out of the slower corners but felt flat on top and I didn't seem to notice much difference with more discs. After reading the article I decided to get the DSP and I'm stoked with it. It has just a slight bit less torque that the e-series and just a slight bit less on top that the 426 pipe, the best of both. I'm happy with the choice I made thanks to the article but it should have told you that this pipe is LOUD! I guess it was geared towards MX with the 426 and not offroad like a WR and that's why they didn't worry about noise but they still could have mentioned it.

'99 WR400
'92 GSXR 7/11
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