got a SPS6280 (62/14) on my truck....under very, very light throttle up hill i can get it to surge ever so slightly. No big deal....i have to try to make it surge for it to happen anyway.

Friday night and today i experienced something different....not sure if you call it surge or _______ ?

i was cruising along at 70mph at light throttle then jumped into the throttle to pass a car....both times i was headed uphill. Heard a sound that sounded like a turbo bark but the whole truck shook...and power cut out for the instant that i heard the noise....but then after that it pulls on just fine right up to the spike at 55 and wastegated at 45-48psi.

Its like too much air at once or something and it barks/coughs? does that even make since?


Is this some form of turbo surge? what exactly is going on?

thanks

 

I have had my turbo stall bad enough to shake the truck. Happens when I am pulling the travel trailer in the hills and hard on it. If I am not careful about how it shifts into OD it's like I just ran over a tire or something. Don't know if that is what is happening to you but if it's right at an RPM drop it could be it.

 

Yeah I have that happen too, when I am pulling my trailer in od. When it drops down to 1950 it will stall like that. I just watch the tach, and when it gets just below the 2000 rpm mark I will manualy turn off the od, no problems since

Kevin

 

oh ok, so its called turbo stall. Hmm....new to me.

thanks guys.

 

That's surge. Keep the airflow up (rpms up) when you nail it...and it won't happen. You may also have to tune your fueling around it too. There were certain fueling "curves" that cause surge with me more than others.

 

I had never had it happen before with different fueling....just scary larry and the SP boost fooler was the on the truck when it happened.

 

That combo probable gave you the "largest" amount of fueling at that low rpm/boost situation...and bam surge/stall.

I have made my tires lock up it can be so violent. LOL. It is a good test of a turbo's core strength.

 

exactly.....the other stacked boxes kept boost up and climbing faster.

yea it happened twice now pretty violently and kind of worried me.....but the good ol SPS kept singin!

 

No...its not that. You fueled too hard at too low of a RPM. Your boost "rose" to quick with that combo at a lower rpm...the motor could not "eat" all of the air...so it stalls the turbo. Won't happen with less fuel.

I bet on a flat strip...with the pedal matted to the floor from the get go it won't happen...and your truck fell feel the strongest yet at that rpm/speed range.

 

Now that sounds really scary...

 

what i meant was with stacking other modules, it keeps boost rising faster never allowing sooo much fuel at such loooow boost.

it only happens on hills when getting into lots of throttle from no throttle..simply learn to drive around it. Sure scared my mother though! she was with me...when it first happened.

I did play around some yesterday....4wd launch at 15psi....0-40mph really fast then the standard programmer feel meaning nearer to stock acceleration through 3rd and 4th. Still prefer modules for top end....wheres my hot juice?!??!

 

Your top end is wherever the last place you left your TST sitting... LOL.

What is your rail pressure doing when you top end is failing off with your current stack?

 

BTW...you still got it backwards...

The chicken comes before the egg. It takes fuel to make boost...

Boost will not rise without fuel.

I know sometimes you can't fuel without boost...TST for example...that is why it does not surge...or have the bottom end that some of the DL have...

So...what it really is...is too much fuel at low boost.

 

TST is on the kitchen table....but not going on my truck. i sold it.

holding...never dropped below 15k....i was also watching the boost gauge, EGT gauge, temp gauge (since i fear blowing a freeze plug after i witnessed it), speedometer, the road (country road thats NOT smooth), sooo long story short i wasn't staring at the rail gauge.

for the first time in the life of this turbo i got over 1200*....1275*


thats exactly what i said. stacked boxes will raise boost faster so i never experience THAT much fuel at THAT low boost....until now with the SP.

The Quad box re-maps so boost comes on almost instantly.....with out it, lots of fuel is dumped into the truck before boost comes on....thus lots of fuel with not enough boost causing this stall/surge.

 

15k is too low. I lose power below 20k.

Your still missing it. Box's don't "increase boost"....they dump in more fuel. Can't have more boost without more fuel. The SP fuels/fools harder at low RPMS that the Quad. It is more like the MP-8.

Anyways...I am not giving you a hard time. I am glad to see you are finally fueling that truck HARD and expereincing some real life challenges. You still have a ways to go...if your only able to get that "small" turbo to 1275 degrees.

Get on a load dyno, run a 1/4, or drag a sled. Either the HP or Performance won't meet expectations...or you will see more realistic exhaust temps.


Back to topic....keep rpms up to avoid surge. That is the key.