tunning help, new c6
06-29-2008, 05:29 PM
#1
tunning help, new c6
hey guys, just got my c6 broke in and it is a sweet motor......i started race tuning it and it is running around 242.......and good smoke so i wanted to try the pinch test and i made a pass wide open and pulled it in and pinched the fuel line right by the inlet on the carb.........the rpms increased and stalled after 3-4 secs, my concern is, that is was more of a machine gun sounding rev up like it was missing. is this ok???
06-29-2008, 07:00 PM
#3
i thought with the pinch test that it would stall imediately if the tune was lean? If it's reving up considerably for 3-4 sec then it will still be a bit rich....
The revs should increase slightly for no more than 2 sec and you on good tune...
These days, i tune to the idle. Once the idle gap is set, adjust the mixture accordingly. If it idles high, it's slighty lean. If it idles low, it's slightly rich....
This will only work when you get the idle gap right, as you can get a false lean if the gap is too big.....
The revs should increase slightly for no more than 2 sec and you on good tune...
These days, i tune to the idle. Once the idle gap is set, adjust the mixture accordingly. If it idles high, it's slighty lean. If it idles low, it's slightly rich....
This will only work when you get the idle gap right, as you can get a false lean if the gap is too big.....
06-29-2008, 07:05 PM
#4
Tech Regular
iTrader: (4)
You want a slow steady increase in rpm, not the machine gun sound. Though the sound could be because it is not fully broken in yet. It will take around a gallon before the engine fully loosens up.
RBs like the bottom a bit on the rich side anyway.
RBs like the bottom a bit on the rich side anyway.
Last edited by largeorangefont; 06-30-2008 at 11:36 AM.
06-30-2008, 09:22 AM
#6
correct me if I am wrong but I tuned my motor on the road.....so on the track it may be slightly different.....probably a little rich? also the low speed needle is 5.5 turns out.....stock settings are 5. my high end is in between 3 and 3.5. thanks for everyones help!!
06-30-2008, 11:24 AM
#7
Interesting. My C6 runs at 212 during a race. Most of my friends that have C6's; theirs run stong and hard at 196-220. That is at 90 degrees outside temp. Sounds like you are a bit lean on the bottom.
06-30-2008, 11:32 AM
#8
Tech Regular
iTrader: (4)
correct me if I am wrong but I tuned my motor on the road.....so on the track it may be slightly different.....probably a little rich? also the low speed needle is 5.5 turns out.....stock settings are 5. my high end is in between 3 and 3.5. thanks for everyones help!!
06-30-2008, 02:00 PM
#9
ok guys thanks....I just didn't think that I would have to richen the bottom that much from the factory. I am also running byrons 20%. I will richen the bottom a couple ours and see if I can get it around 210 with the body on. and see how it does.
06-30-2008, 06:50 PM
#10
forgot to mention......i am running a werks fironi coooling head, think that is better or worse than the stock c6 head
07-01-2008, 05:33 AM
#11
I was wondering what my idle gap should be set at how far from closed? I am going to set it and tune the low end for idle.
07-01-2008, 09:05 AM
#12
Tech Regular
iTrader: (4)
The low end on my S7 is set so that when you open the carb all the way, the tip of LSN is exactly half way across the carb throat.
So if you are running the OEM 7mm restrictor, you should have about a 3.5mm gap between the carb throat and the tip of the LSN at WOT.
That will get you in the ballpark. A C6 will run a similar setting.
So if you are running the OEM 7mm restrictor, you should have about a 3.5mm gap between the carb throat and the tip of the LSN at WOT.
That will get you in the ballpark. A C6 will run a similar setting.
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