SAI delete

dougl said:

The AFR’s in the AFR table in the tune serve two purposes. The first is to calculate the amount of fuel to inject. That is, a value in the fuel table, which is mg of air multiplied by a constant, divided by the corresponding AFR. This gives mg of fuel. The second is to allow the ECU to go into closed loop, using the lambda (O2) sensor. This is for fuel efficiency. This applies only in the block of the AFR table where the value is 14.5 or thereabouts and only at steady throttle and low engine load. Fueling at the top end and under acceleration is not affected. The O2 sensor is designed to detect AFR between and 14 and 15. This corresponds to sensor output voltage between about 0.1 and 1.1v. If the output voltage is in the upper part of this range, the ECU leans out the mixture, and visa versa. A stock bike with a stock tune is not going to have its valves burned up. I’m all for fuel efficiency and not poisoning the air. Where I live, however, motorcycles are exempt we can do what we want to them.

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Nashvegas said:

I like your last sentence! What about mapped bikes with aftermarket headers/pipes? Any potential for valve damage? Does Triumph (or any other manufacturer) add EPA/Euro 5 devices to their race bikes to gain “fuel efficiency?” Or power? Hmm…

If a Triumph dealership had two Rockets sitting there that looked exactly the same but one had zero emission nannies and a little sign, (For track use only) I know which one I would buy. Karen heads around the globe would explode.
@dougl

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dougl said:

Of course you can ruin the engine. I don’t get your point about racing. There’s still racing, no?

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Nashvegas said:

I already have aftermarket Vandemon pipes and map/dyno but I will be getting larger headers/pipes soon. I want to make it the most efficient/srong/happy engine without any regards to mpg or emissions. But not at the risk of damaging the engine. If that can be done leaving the o2 sensor/cannisters/EPA stuff in place, great! But all that stuff seems to compromise engine power for the sake of emission compliance. Hence, my racing analogy. If they were getting the same power and even better mpg they would all be adding that stuff. Weight issue, maybe? I doubt it but that’s why I’m trying to learn how to achieve the best results with this engine. Would Triumph add all of that stuff to an engine if there was no Euro5/EPA constraints? How much power does it actually rob? I have no idea.

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dougl said:

So when you get the new headers, you need to get it dynoed again, right?. I don’t think the O2 sensor, SAI or EVAP limit max power. How would they do that? We know that derestricting the electronic throttle gives a ton of additional max power. You might want to remove the O2 sensor and SAI to reduce popping on decel. I’m not arguing that anyone shouldn’t remove this stuff from their bikes. I’ve done it.

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dougl said:

Did you remove the cat? How much popping are you getting?

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Nashvegas said:

No cat, and it’s not purring (yeah, I went there) but it definitely will “pop,pop..pop…pop…..pop” getting further apart as it decelerates. It’s not really annoying but I would be fine with less or totally gone.

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dougl said:

The popping is caused by ignition of unburned fuel in the exhaust. Adding air, as SAI does, makes the burn hotter, so this increases popping. Do, get rid of SAI. I found that the O2 sensor accentuated decel popping on my 2005 Rocket. So I removed it and this helped. I had a full Jardine exhaust and triple filters on my 2007 Rocket. The popping was explosive. Even after I had it dyno tuned with a Power Commander 3. The popping thing is common on bikes with open exhausts. I saw a Dynojet video where they suggested adding fuel at closed throttle which is where popping occurs. Adding more fuel makes the mixture cooler in the exhaust to the point where it won’t ignite. I did this myself and the popping stopped. You could install a Power Commandet 6 and do this yourself. Trying to add fuel at closed throttle with Tuneecu is problematic. That’s because the ECU is using manifold pressure, not throttle position to do the fueling at closed throttle. You could try adding fuel in the L tables at low pressure. If anyone has done this successfully, I’d like to know.

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