experiences with hitting fuel cut and over boosting

[kleenf4i]

So, like the title says in trying to get some feed back as to what happens when hitting fuel cut and over boosting.obviously running lean, and detonation.but should hitting fuel cut produce these side effects? In other word, being stock fuel, at 14 psi, should you be able to rev out without worrying? Or will it still produce side effects?I have only built 2 turbo cars, this is my third.before the fuel management was over kill for the boost, now it's the opposite so I'm learning here.

 

[Cdc1221]

It would depend on the turbo. A t25 at 14 psi is fine. A 16g may hit fuel cut, specially with cooler weather. Fuel cut is exactly as it says, it cuts fuel. The reason it does hit fuel cut is because the ecu 'sees' so much air and thinks its too much for the cars fuel system to handle, so it cuts fuel before engine damage can occur, primarily from detonation. This is normally felt as a slam, not a stutter. Youll be looking in your rearview for your tranny. Literally. I broke my trans mount hitting fuel cut.

 

[kleenf4i]

Ok that's exactly what I just experienced.it felt like I dropped a gear out of the trans.I want trying to on purpose but it scarred me badly..I guess from what your saying the ecu cut the whole motor so it didn't damage. This is good.my other cars I had to monitor myself.there was no fuel cut.it was either on point, or blow up.yes I'm on 16g..people have told me 14psi is fine.I spiked to 20 when it did the fuel cut.not a good feeling.

 

[Cdc1221]

You should probably check into doing some work to the wastegate. From what ive seen, e3 16gs are notorious for boost creep. Check this out http://www.dsmtuners.com/forums/art...boost-creep-modified-wga-peepers-mod-how.html

And no its not . When i was on the stock mas, sometimes it would hit fc at as low as 15, and sometimes i could hit 20 psi without ever hitting fc. This was before i got my mbc set right

 

[kleenf4i]

in the next couple days i should have my boost controller i ordered. so ill throw it in. that looks like good advice. I realize this is all noob stuff. but im coming from honda, where we would ALWAYS overload the fuel and basemap the fuel curve to fit the psi. on this car its opposite, so im still learning. thanks for the quick reply. and your help!

 

[Cdc1221]

Yea no problem. Thats what we're here for . To try to stop you from making the same costly mistakes we have

And just for future reference, its not really the psi, its the airflow, the actual amount of air that is taken in and exhausted, that effects this. Like right now, with the ambient temps being so low, my car is cutting at 15 lbs or so where a couple weeks ago it wasnt

 

[kleenf4i]

good deal im going to see if my boost controller will fix the spikes. , i went from no boost to , too much boost. such is life. if not i will spend the money to go to an external wategate. Ill need it here in the near future anyway. im planning on pushing 400 hp. thats my goal. so im starting to look for fuel upgrades right now.

Yea no problem. Thats what we're here for . To try to stop you from making the same costly mistakes we have

And just for future reference, its not really the psi, its the airflow, the actual amount of air that is taken in and exhausted, that effects this. Like right now, with the ambient temps being so low, my car is cutting at 15 lbs or so where a couple weeks ago it wasnt

i also read that these cars like a 1:1 ration of boost to exhaust. I do believe this id true. dsm is very picky about how it runs..Again, honda liked a medium of whatever the values I put into the base map would see. It was very easy to fine tune them. I guess im just not deep enough into this car to compare it whith "what i had". and yeah i agree with it being cold, the air is super compressed by itself.

 

[Cdc1221]

Im confused by the boost to exhaust 'ratio'

 

[kleenf4i]

Yea no problem. Thats what we're here for . To try to stop you from making the same costly mistakes we have

And just for future reference, its not really the psi, its the airflow, the actual amount of air that is taken in and exhausted, that effects this. Like right now, with the ambient temps being so low, my car is cutting at 15 lbs or so where a couple weeks ago it wasnt

i also read that these cars like a 1:1 ration of boost to exhaust. I do believe this id true. dsm is very picky about how it runs..Again, honda liked a medium of whatever the values I put into the base map would see. It was very easy to fine tune them. I guess im just not deep enough into this car to compare it whith "what i had". and yeah i agree with it being cold, the air is super compressed by itself.

Im confused by the boost to exhaust 'ratio'

meaning if the ratio of the intake of boost superceedes what is able to be let out of the exaust on a scale of 1:1 ratio it will defiantly cause issues.

 

[dSmlightning]

Kinda old post but dose that mean a exhaust leak near the turbo would cause boost creep

 

[Cdc1221]

Kinda old post but dose that mean a exhaust leak near the turbo would cause boost creep

No, it will cause the turbo to be laggier than normal depending on the size of the leak as it is ex gas not spinning the turbine wheel

 

[99ECLIPSEGSXDSM]

It is possible to get boost creep from a leak but very unlikly. Leaks are more related to lag problems. I have one now but have to wait for spring to fix it. Winter sucks