evo3500
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| posted on 21/3/08 at 09:08 AM |
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V- Twin emissions
Help !
I am having trouble getting my engine to SVA emission requirements.
The engine is an Aprilia mille V-Twin.
I am running a 300 cell cat,and power commander,basically with single header pipes coming together in y-peice,then into cat,then into silencer,gas
goes into silencer in the rear corner into an open chamber,about 2.5 inches deep,seperated b a inner bulkhead,then the perforated tube comes through
the bulhead centrally into the open chamber,the gas is then forced into perf tube,goes through the bulkhead,and then goes along the straight centrally
mounted perf tube tube with exhuast wadding each side until it exits at the rear.
I took it to a chip tuning in bromsgrove an approved BEC Dynojet Centre, to try and get it set up,he said he couldnt get the figures,after trying for
an hour or two.
He said no problem with Co and hydrycarbons,but when these where right lamba reading went to high.
I dont use the stock Aprilila silencer, he said the exhaust box needs to be different,as he said V-Twins can generate a pulse,and pull air back into
the exhaust pushing up the Lamba is this true ?
Anyone put a v-twin through SVA if so how did you manage it ?
Im running out of ideas,will it work with one of the aftermarket closed loop cat systems. Currently the car isnt fitted with a lamba sensor or cat
kit.
All ideas welcome SVA is looming next week !
Thanks
Simon
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froggy
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| posted on 21/3/08 at 09:16 AM |
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ive only done one for a mate but we set the mixture to 0.5 at 2.5k rpm and than used an air bleed to in the throttle body rubbers to adjust the lambda
to get it at just under 1.030. how high is the lambda going up to? the higher it gets the weaker the mixture but a cat will normally cope with a
slightly rich mixture as long as the afr is right
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smart51
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| posted on 21/3/08 at 09:30 AM |
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What he's saying is that he had to lean it off a lot to get the CO and HC down. (lambda is the excess air ratio. High lambda = lots of air
compared with fuel)
With my R1 engine, I got the lambda into the right range and the (replacement) cat cleaned up the emissions. Is your cat OK?
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evo3500
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 posted on 21/3/08 at 10:23 AM |
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Thanks guys for the info.
I thought about the cat. It is new but how can it be tested ?
How does it get damaged ?
I have another,but if i fit it do I run the same risk of burning it out ?
I have done around 50 miles testing with the cat in place,on the stock bike settings. I have only just fitted the dynojet prior to taking for set
up.
my bike is fuel injected does this make any difference ?
On my GT1 with thunderace engine in on carbs, I just adjusted the carb mixture scews right down had cat fitted and R1 end can sailed
emissions,although it was very sensitive to adjustment for lambda the most minut touch of the mixture screws altered the lambda,they let me do this at
sva whilst on the machine. machine.
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