i just bought a gn that had a precision gtq70 turbo on it and i took it out to get a feel for the car and instead of the typical spoolup sound, after about 15lbs it just sound like its surging. the car make 20lbs of boost even when its making the noise, and is still pulling. i dont think i am, but if i bump the rev limiter could this cause it to surge?
turbo surging/sneezing under boost?
- Thread starter 4-71/Z-28
- Start date
It worked for me also!
- Joined
- Feb 18, 2006
Thats one problem with running a big turbo. Mine will surge if I try to part throttle it. For me, it starts around 5psi and will go away around 15.
How close to the turbo are you guys running the tornado?
How close to the turbo are you guys running the tornado?
- Joined
- May 28, 2001
"just monitoring with a scanmaster".
What are the SM readings when this takes place?
Fuel pressure is? when this takes place.
Alky working?
May not be "surge", but timing retard, MAF drop out, valve springs going away, etc, etc.
What are the SM readings when this takes place?
Fuel pressure is? when this takes place.
Alky working?
May not be "surge", but timing retard, MAF drop out, valve springs going away, etc, etc.
gnloyalty877
t'squick6
- Joined
- Jul 15, 2007
I'd like to know that too.
I have the tornado right at the end of the maf pipe, you want it as close to the inlet bell as possible. I had that part throttle surge also with the TA 49, as soon as it would hit about 5 lbs. I would get that surge. No more surge with this tornado in place!
Tornado KI-75 is 3" thats what I'm using.
maf dropout sounds like a possibility, since i have now discovered that when i try to free-rev the car it wont go above 4400 with out cutting out. what would cause that? bad maf? the scanmaster shows that its counting air, would i be able to see the maf drop in count on the scanmaster?
Eric Stage I
TurboTweak Guy
- Joined
- May 25, 2001
The chip program is not "tuned" for free reving. It will assume that boost will be coming in and start adding a lot of fuel. It could just be choking on fuel. I wouldn't use free reving as a test for anything.
I would go into the chip settings and reduce the timing to 18*, then turn off the alky and turn your boost down to a safe level. Start there and see how the surge is when driving. If it still does it with the alky off, then we'll have to move on to something else.
Eric
I would go into the chip settings and reduce the timing to 18*, then turn off the alky and turn your boost down to a safe level. Start there and see how the surge is when driving. If it still does it with the alky off, then we'll have to move on to something else.
Eric
i didnt know that, thanks for youre input eric , that really relieves me i thought something like the maf may be on the fritz or something of that nature, i was trying to decide what to try, new maf, or tornado. looks like ill be trying a tornado like roc87. i really appreciate you chiming in, i just figured if i couldnt free-rev then something is REALLY wrong. i feel much better
My setup does it bad too.
At part throttle from 5-20lbs it sneezes, like my turbo is flowing too much air and can't use it fast enough...????
WOT at 20lbs it is sneezing with no knock (translator is set to +4 fuel at wot)
turned boost down to 18lbs (tt chip is for 16-18lbs) set translator to +0 fuel at wot) - no knock
WOT at 18lbs wasn't nearly as bad. Still happens though.
I have a T64E, 60's, TT chip, Translator, Headers, DP, 4" Front Mount and pump - everything else is stock.
Note* Pressure readings are taken from the vacuum block on top of the plenum.
I guess sneezing is the same as surging.
It makes the same sound at wot as it does when you instantly get out of the throttle under full boost.
At part throttle from 5-20lbs it sneezes, like my turbo is flowing too much air and can't use it fast enough...????
WOT at 20lbs it is sneezing with no knock (translator is set to +4 fuel at wot)
turned boost down to 18lbs (tt chip is for 16-18lbs) set translator to +0 fuel at wot) - no knock
WOT at 18lbs wasn't nearly as bad. Still happens though.
I have a T64E, 60's, TT chip, Translator, Headers, DP, 4" Front Mount and pump - everything else is stock.
Note* Pressure readings are taken from the vacuum block on top of the plenum.
I guess sneezing is the same as surging.
It makes the same sound at wot as it does when you instantly get out of the throttle under full boost.
I'm guessing that a larger intake/plenum would help?
A couple notes that may help the decision process.
The compressed air goes from a 2.5" outlet (turbo) to 3" pipes to 4" ebay front mount core (save the ebay rants for later, I know it isn't as efficient as the rjc units but that's a different thread all together) to 3" pipes to the 2.5" stock throttle body...
Now, what I believe is happening is the turbo's doing its thing and producing a ****load of cfm, it goes into the core and expands (pressure drop) then tries to get squeezed back into the throttle body (poor little fella). So when this is happening the air gets "backed up" and causes the compressor to "fight" with itself thus causing "surging/chatter/sneezing" or whatever people call it.
Buick gurus please chime in....... here ->
A couple notes that may help the decision process.
The compressed air goes from a 2.5" outlet (turbo) to 3" pipes to 4" ebay front mount core (save the ebay rants for later, I know it isn't as efficient as the rjc units but that's a different thread all together) to 3" pipes to the 2.5" stock throttle body...
Now, what I believe is happening is the turbo's doing its thing and producing a ****load of cfm, it goes into the core and expands (pressure drop) then tries to get squeezed back into the throttle body (poor little fella). So when this is happening the air gets "backed up" and causes the compressor to "fight" with itself thus causing "surging/chatter/sneezing" or whatever people call it.
Buick gurus please chime in....... here ->
