Mcwille117

Disappointing dyno

33 posts in this topic

Ok quick (sort of) back story. My son races flat track this is our first year on the 450. We bought our 250 already built by someone that is known and does winning pro motors. Decided to have the 2011 crf450r we picked up built by him as well. Was given a VERY healthy budget, and several times he said we should be in the low 60s when he's done. Come to find out that my son's number one competitor also gets his motors done by the guy and the dyno that he uses is at the shop of our competition's sponsor. Oh well what can you do. The shop happens to be the closest to us but we won't get any work done there because there is the feeling and fear that they would do anything to keep my son from beating their racer.  Picked the bike up from the dyno shop because it is almost an hour closer than picking it up at the builders shop. Was not impressed...

Max power = 54.63 at engine rpm = 9.82 

for over $3000 getting 2 hp over stock feels like something isn't right. Now I know we're only running the yosh pipe not a down pipe but still... 

head was ported and polished, custom cam, cp corrillo internals, ???

the shop said the soft tire and the humidity are the reason it's not higher but does that number seem low to anyone else?

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Something doesn't seem right.  A few yrs. back I rode an 11 model that had a full Yoshimura engine package that produced aprox. 62 hp atrw & it was definitely noticeable over a stock engine.

The 09-12 CRF450r's had basically the same engine.  MXA did a pipe dyno comparison on the 09 model & with just the yosh pipe (remap ?) it produced  54.34 horsepower at 9400 rpm.

https://motocrossactionmag.com/we-test-2009-honda-crf450-exhaust-systems-dr-d-pro-circuit-fmf-yoshimura-vance-hines-and-stock-get-the-dyno-sound-and-powerband-treatment/

 

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That's why I feel something is way off. Stock on the 2011 was 52 at the wheel. We're very far from stock. I won't post the dyno sheet or name the builder because I don't want to throw anyone under the bus especially since this is very fresh and hasn't been worked out yet. The yosh setup is the full stainless system. Everything in the engine was top of the line and the port work was supposed to match a head in his shop that he matches all the 09-12s to, that made 64hp. Without the downpipe and intake we were expecting low 60s. Not 54 for sure...

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2 hours ago, Mcwille117 said:

That's why I feel something is way off. Stock on the 2011 was 52 at the wheel. We're very far from stock. I won't post the dyno sheet or name the builder because I don't want to throw anyone under the bus especially since this is very fresh and hasn't been worked out yet. The yosh setup is the full stainless system. Everything in the engine was top of the line and the port work was supposed to match a head in his shop that he matches all the 09-12s to, that made 64hp. Without the downpipe and intake we were expecting low 60s. Not 54 for sure...

How much work was done with the EFI? And is it the stock Honda box, or a Vortex?

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2 hours ago, Shawn_Mc said:

How much work was done with the EFI? And is it the stock Honda box, or a Vortex?

Bingo...that is an extremely low number for those mods. You should be, at the minimum, hitting high 50s

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6 hours ago, Fenmore said:

Bingo...that is an extremely low number for those mods. You should be, at the minimum, hitting high 50s

The issue is that with the EFI, it only does what it's told. A carb is a little bit self reactive. A larger intake pulse is going to pull more fuel (to a point) through the same jet. That same intake pulse only gets what it gets on an EFI setup that's unmodified. These setup run a MAP, not a MAF sensor, HUGE difference, and they dont have an o2 open loop to talk to either. You've gotta get something pretty wrong to only make 52 hp out of a modern 450. Or simply not try.

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5 minutes ago, yz250f 78 said:

Tuned to a race fuel?

Even if you tuned for race fuel, then ran pump gas, it still wouldn't kill the HP by 10-15%. 2-3 hp sure..but not 8-9. 8-9 is a different problem.

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51 minutes ago, Shawn_Mc said:

Even if you tuned for race fuel, then ran pump gas, it still wouldn't kill the HP by 10-15%. 2-3 hp sure..but not 8-9. 8-9 is a different problem.

No I'm saying if your runnin pump gas with a port then maybe 54hp  

a lot of power is made with race gas that is oxygenated   

 

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1 hour ago, yz250f 78 said:

No I'm saying if your runnin pump gas with a port then maybe 54hp  

a lot of power is made with race gas that is oxygenated   

 

Like I said, it wouldn't be that drastic. Unless the port is just junk. That's not impossible...

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I have a 64+hp 2013 450cc R, you'll know if/when it is making that sort of power because the people that you blow by on the track will come find you and ask what you have into the motor.

 

 

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We run Dragon 110 for are fuel. Stock airbox K&N filter, and the 54 hp dyno pull was them tuning it, remapping the Honda ecm. 

Ok talked to the builder, not really convinced, but here is what he said. The engine is where it should be. The most he has ever seen on a dyno with an up-pipe (we're running yosh RS-4 system) is 59hp, that same motor made 64hp with a billsbuilt downpipe. He said the soft tire ate up about 3-4 hp. We will gain a little with airbox/intake boot change and adding a ignition system. He said the internals and motor are spot on. 

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No offence to the OP but if high HP is necessary for flat track why are you using a 2011 CRF? The YZ, KX, and KTM are all more powerful out of the box. Even the current CRF has higher numbers stock. It seems that the cost involved to get where you need to be is really high on the bike you’re running. 

Edited by Dklassen
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First, you should of had the shop that did the last dyno run, do one prior to the engine work, having the same guy do it. Get a bench line.

Second, a different day (air density) can have a 5% difference easy on HP numbers.

Engine work, was the head flow benched for optimum flow based on the cams and bore? There is something call 'slowed down for racing' where I've seen all sorts of mis-matched 'go-fast' parts used, massive, shiny ports and end up with less power than stock. All parts must be selected to mesh with one another to work.

What tires were used? I assume street bike tires and not MX tires. If so, that can easily affect numbers by 20%

Finally, what kind of dyno? Dynojet rolling drum or a true brake dyno?

A brake dyno run by chain and no tire is the most accurate.

 

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52 minutes ago, William1 said:

First, you should of had the shop that did the last dyno run, do one prior to the engine work, having the same guy do it. Get a bench line.

Second, a different day (air density) can have a 5% difference easy on HP numbers.

Engine work, was the head flow benched for optimum flow based on the cams and bore? There is something call 'slowed down for racing' where I've seen all sorts of mis-matched 'go-fast' parts used, massive, shiny ports and end up with less power than stock. All parts must be selected to mesh with one another to work.

What tires were used? I assume street bike tires and not MX tires. If so, that can easily affect numbers by 20%

Finally, what kind of dyno? Dynojet rolling drum or a true brake dyno?

A brake dyno run by chain and no tire is the most accurate.

 

He's said "soft tire" a couple times, which kinda makes me wonder if it was knobby, or a flat -track Goodyear or something. If the tire isn't spinning on the drum, it really shouldn't matter unless you've gotta bury the thing with the tie downs and your working the tire sidewall to death. The dyno operator and the way the throttle is applied can make a huge difference too.

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2 minutes ago, Shawn_Mc said:

He's said "soft tire" a couple times, which kinda makes me wonder if it was knobby, or a flat -track Goodyear or something. If the tire isn't spinning on the drum, it really shouldn't matter unless you've gotta bury the thing with the tie downs and your working the tire sidewall to death. The dyno operator and the way the throttle is applied can make a huge difference too.

Flat track maxxis dtr cd-3. Instead of a Goodyear or at least a maxxis cd-5

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1 hour ago, Dklassen said:

No offence to the OP but if high HP is necessary for flat track why are you using a 2011 CRF? The YZ, KX, and KTM are all more powerful out of the box. Even the current CRF has higher numbers stock. It seems that the cost involved to get where you need to be is really high on the bike you’re running. 

Just trying to max the hp out of the bike we have so when it's time to move to the next lvl we will buy a new bike and build it to maxed out. My son is only 14 So we have two years before he moves up. Starting with the 2011 crf because we got a great deal on it and it is a great place to start. 

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14 minutes ago, Mcwille117 said:

Just trying to max the hp out of the bike we have so when it's time to move to the next lvl we will buy a new bike and build it to maxed out. My son is only 14 So we have two years before he moves up. Starting with the 2011 crf because we got a great deal on it and it is a great place to start. 

There's no reason why you shouldn't be able to wring 60 hp (peak) out of the 2011 engine. With the right head work and cam timing and a decent pipe, up or down style.

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