barking under load!

dangerous06

dangerous06

diesel tech
Ok so i was towing a trailer up a 8% grade about 40-50 it dropped into a higher gear and lugged me down so i floored it to downshift blew a wall of black and surged forward but when i hit about 30psi the turbo started barking like when you let off real fast after WOT! Any ideas?
 
Did it start barking when the rpm's dropped for the shift or after the lower gear shift as rpm's climbed? Only thing I can think of is that it barked when rpm's dropped and kept barking back up the rpm's. Sounds like it might have been a pretty harsh shift? And how long did it last?
 
Started after the down shift when rpms picked up hit about 30 psi and kept doing it everytime i would get into it so i feathered the throttle to where it didn't do it! Yeah I thought it was weird first thought was wastegate wasn't adjusted right. haven't had a chance to get into it to see if I can do it again. honestly haven't floored it yet seems 1/4 pedal is all i need to get up to 80 in 100ft! OK maybe 200! But wow this thing really pulls hard my stocker hit a wall at 40psi but this thing just keeps going!
 
You experienced surge. It happens when you try to operate too far to the left of the compressor's map. More rpm helps.
 
all i know is my buddies did something similar pulling a trailer witha 2wd cummins on the back, tranny was flaring/slipping
 
That's compressor surge. Your turbo isn't happy there. Find another gear to get the rpms up to prevent that.
 
Man you guys are quick! I wasn't through reading his reply and was gonna say surging, but you guys beat me to it.
 
you can tow with power if you want, just gotta keep in your turbo's efficiency range... with a bigger tune, it takes less throttle to make fuel... but our trannies are stupid and we can't tailor the shifting characteristics to our tunes :(

so the tranny sees very little throttle input and doesn't kick down to a lower gear

so, you can manually drive the thing (which kinda sucks... you bought/built an automatic for a reason, right? :eek: ) or, you can turn the tune down a good bit so that the tranny will automatically be in a more correct gear
 
yeah I hear you Forrest I took it out of Tow hual and put it in OD off that helped alot!
So lesson learned! Man I wish there was a dyno that can handle my dually in
San Diego! I think I may be over 600 now!
 
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