max rpm for xb12 ecm?

[Xb12armyguy]

Hey guys im planning on this winter building a big bore xb9 engine to replace my 12, I know my map on my 12 ecm only goes to 7k would I need to change to a xb9 ecm to rev past 7 and what is the max rpm limit for a xb9 ecm?

 

[wolfo68]

xb 9 is 7200, pre 08 12's 6800, post 08 7000

 

[Xb12armyguy]

Hey thx for the info, maybe I didnt ask it the correct way. Im aware of the stock redline im asking how far the ecm will allow rex with limiter removed I know I can take my xb12 to 7200 if I wanted to.

 

[Xb12armyguy]

Lets say I wanted to spin a built xb9 engine to 8500 could I do that with xb9 ecm?

 

[theoctopus]

Yes.

 

[Xb12armyguy]

Ok great thx!

 

[moshaholic2]

Reviving an old post.

Just returned my 09 XB12ss to stock, was running a ebr race ecm and after market exhaust...

I miss the extra revs of the race ecm, but the bike runs better with stock ecm.

Can I bump up my redline to 7k? Do the stock fuel/timing maps go that high?

 

[lawdog]

Stock tables run up to 8,000 rpm.

Soft limit on your bike is 6,750 / 6,700.
Hard limit is 6,800 / 6,750.
Kill limit is 70,50 / 7,000.

EBR bumps it up 300 rpm higher.

I would not recommend running much higher rpm then that due to piston speeds on the XB12. It is hard on the lower roller bearings of the rods. I imagine you might be getting into valve float too but I don't know enough about the heads to say for certain.

You can easily adjust your rpm limits back to the EBR ECM settings. You will need to adjust the high and low for the soft, hard, and kill limit.

 

[go cytocis]

Just returned my 09 XB12ss to stock...Can I bump up my redline to 7k?

There's not much point in raising the redline on a stock set-up because your HP peak will have long-passed by the time you get to 7,000 rpm.

 

[EricZ]

And your 09 hard limit is 7100rpm. All the 08+ XB12 models are 7100rpm stock.

 

[Cooter]

What makes you think your bike runs "better" on the stock ecm vs. the EBR one? I bet theres a minor tuning issue like a mismatched pipe or something. Why are you riding it at that high an RPM anyway? Is it a track only bike?

Also, and this is very important for you moshaholic2 with an aftermarket air filter and exhaust (and now with stock tuning) your bike is running very lean. Lean+RPM=Kaboom.

Although I agree wholeheartedly that just raising the redline RPM just because you miss it, is a verybad idea. EBR seems to think an extra 300RPM on stock internals is fine.
Most every XB dyno chart I've seen looks just like this one.

The HP curve just keeps climbing 'till they shut it off!

 

[go cytocis]

The HP curve just keeps climbing 'till they shut it off!

[confused] Looks to me like it plateaus at ~6600.

 

[Cooter]

Yes, but you don't shift right at the peak. You shift past the peak. That way your average hp between the shift points is higher.

On this exact chart, there is an argument about the torque curve diving off too. I just posted it as a HP at 7000RPM example.


There is a fun conversation here we might take to a different thread, Me likey some engine theory discussion

 

[go cytocis]

Yes, but you don't shift right at the peak. You shift past the peak

That's certainly one way of doing it, but as you know, just like suspension set-up & braking technique, rider style also comes into it too. Some folks swear by shifting only once you've got all the way to redline because the engine's rotational inertia is at its peak. Some say horsepower is irrelevant altogether & it's all about torque. Each technique is capable of getting a rider around a track just as fast as another.

Therein lays the question however: is moshaholic really talking about going racing, or just street riding? On the street, optimum shift points are dictated much more by the traffic light that just turned orange, the cager that's about to cut you off & the stray dog up ahead.

Me likey some engine theory discussion

Me too

 

[gbalias]

i hate it when the hp and tq scales dont match.