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Discussion Starter · #1 ·
have been trying to decide which is the best fuel injection module,between these two compines cobra makes two fuel Er's for the raider one has a setup where you can use your oxygen sensor it is part number 92-1777cl the other one does not use the oxygen sensor, i am trying to figure out what the main difference is between them? i talked to one of the techs at dobeck performance about it and he said that there programmer will be ready in about 2 weeks, they do not have a programmer that uses the ogen sensor they say to just unplug it that you really cant adjust your settings correctly, if you have a oxygen sensor hooked up? who is right? can anyone explain this to me so i can understand this, i think
it would be better to have the oxygen sensor working? Burt
 

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little burt said:
they say to just unplug it that you really cant adjust your settings correctly, if you have a oxygen sensor hooked up?
Anyone that says you can't adjust a FI car is a moron. No offense to Dobeck and I'm not talking against them because i have a Cobra fuel controller.

Bikes/Cars have been tuned with O2's since carbs have been dropped.

All that is being done is adding/removing fuel to what the stock computer gives - that is about it. The BENEFIT to still using an O2 is that your stock computer will still be able to adjust + or - the fuel that is given per weather conditions, altitude, etc.

NOT using an O2 would yield the same results as a carbureted motor - a static AFR that can't change with the above mentioned variables.

The ONLY thing to note is that when the bike is cold - the stock PCM will dump more fuel into the motor at idle - often times - causing a tiny bit of black smoke on snapping the throttle. The PCM does this to get the bike warmed up to operating temperature faster.

Why the puffs of smoke? Too rich. You program the fuel controller and tune it for when the bike is warm - because that's when you'll be doing the most riding (unless you only like riding for 5 minutes at a time). So naturally - when idling at 14:1 - the stock PCM still thinks it's running lean - and therefore dumps more fuel in.

The fuel that any aftermarket controller gives - is subtracted before giving the O2 readings back to the PCM - so the bike always thinks it's getting a proper AFR - otherwise - the bike would lean itself back to normal... which means... here comes the popping, choppy accel, etc all over again if you have aftermarket parts on the bike.

Using an O2 is the way to go if you like to ride your bike - once you're setup you're a-ok. If all you do is trailer it to the race-track and put on 1 mile a night (stictly from 1/4 mile runs) - then sure - don't use an O2 - but tune your bike every night for weather conditions, etc to get the proper AFR to squeeze the most power out of your bike.
 

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Ninja-Matic said:
little burt said:
they say to just unplug it that you really cant adjust your settings correctly, if you have a oxygen sensor hooked up?
All that is being done is adding/removing fuel to what the stock computer gives - that is about it. The BENEFIT to still using an O2 is that your stock computer will still be able to adjust + or - the fuel that is given per weather conditions, altitude, etc.

NOT using an O2 would yield the same results as a carbureted motor - a static AFR that can't change with the above mentioned variables.
Interesting, that totally contradicts the claim that Dobeck advertises. I would think they have quite a bit of exoertise in this subject. Here is a quote from their website.

Our product attaches directly to the trigger wires of the fuel injector and only modifies the length or duration of the fuel signal. That way, all of the factory-specified and required settings for temperature adjustment, altitude and barometric pressure adjustment are totally unaffected and continue to function as originally designed.
 

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Ninja, Did you get the Cobra FI with the O2 then (i'm assuming based on your response above).


Thanks,

Aaron
 

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Madcruzer said:
Interesting, that totally contradicts the claim that Dobeck advertises. I would think they have quite a bit of exoertise in this subject. Here is a quote from their website.

Our product attaches directly to the trigger wires of the fuel injector and only modifies the length or duration of the fuel signal. That way, all of the factory-specified and required settings for temperature adjustment, altitude and barometric pressure adjustment are totally unaffected and continue to function as originally designed.
That's how it would work WITH the O2 connected... but you said in your first post:

little burt said:
they say to just unplug it that you really cant adjust your settings correctly, if you have a oxygen sensor hooked up
Unplug it? Leave it in? Which one is it?

Uplug = static - the CPU will not be able to adjust AFR properly (baro, temp, alt, etc) after the initial tune.

Plug = it works just like the rest of the O2 equipped fuel processors.

One of those is your answer. What you're suggesting is that Dobeck says to unplug the O2 and that your stock PCM will still adjust properly - which isn't possible seeing as how in order for your PCM to adust - it needs an AFR from an O2. In that case - I'd buy from someone else.
 

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Ninja-Matic said:
alsmith_54 said:
Ninja, Did you get the Cobra FI with the O2 then (i'm assuming based on your response above).
Yeppers.

Also, have you noticed much of a difference doing the airbox mod (meaning... how much difference between stock and an air kit)
 

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Discussion Starter · #8 ·
Ninja-Matic said:
Madcruzer said:
Interesting, that totally contradicts the claim that Dobeck advertises. I would think they have quite a bit of exoertise in this subject. Here is a quote from their website.

Our product attaches directly to the trigger wires of the fuel injector and only modifies the length or duration of the fuel signal. That way, all of the factory-specified and required settings for temperature adjustment, altitude and barometric pressure adjustment are totally unaffected and continue to function as originally designed.
That's how it would work WITH the O2 connected... but you said in your first post:

little burt said:
they say to just unplug it that you really cant adjust your settings correctly, if you have a oxygen sensor hooked up
Unplug it? Leave it in? Which one is it?

Uplug = static - the CPU will not be able to adjust AFR properly (baro, temp, alt, etc) after the initial tune.

Plug = it works just like the rest of the O2 equipped fuel processors.

One of those is your answer. What you're suggesting is that Dobeck says to unplug the O2 and that your stock PCM will still adjust properly - which isn't possible seeing as how in order for your PCM to adust - it needs an AFR from an O2. In that case - I'd buy from someone else.
if i remember right the guy i talked to said there processor was not setup tp use a oxgen sensor so just plug it up.
 

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i hate to get into talks that start like this but here we go
the cobra efi that uses the o2 sensor does nothing to your bike before 2700rpm
thats how they pass epa standards so they can use the o2 sensor ,all the o2 sensor
is for is low rpm fine adjustments, the ecu makes most of its adjustments off
of temp,pressure,air flow,ect ect
the reason to remove the o2 sensor is because the cobra and the tfi plug in after the ecu
and the o2 sensor would sense any fuel changes not intended to be made by the ecu
and the ecu would lean the bike out more to epa standards . remove the o2 sensor
and the ecu doesn't sense the extra fuel you add , and doesn't try to lean it out
but the ecu still makes changes based on all the other inputs

I ran the cobra first and it did nothing for my low end and i still got the decell backfire
so i did more research and found out how cobra made the epa cut and why.
I now run the tfi with no o2 sensor (i got the o2 sensor bypass plug) my bottom end
now has come alive and i run from Sacramento (sea) to Tahoe (7000+ ft) with no problems .
also you can use the tfi with the o2 sensor you just have to leave the low speed setting
at zero

if efi only made adjustments off of the o2 sensor than what are mass airflow sensors , knock sensors , air temp sensor , ect ect for , the o2 sensors job is to make fine adjustments at a crusing speed
 

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Yea what little burt asked! :icon10:
 

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i ordered it from dyno jet , off thier web site im not shure of the part number but i think it fits all yamahas with the o2 sensor
 
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