Fuel starved??????
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Pro
Joined: Sep 2010
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From: Murrysville PA
Fuel starved??????
My 2005 vert is 3 months old, 6 speed manual with 24,000 miles.
I have noticed that with the traction control off during spirited acceleration, in first and second gear, there seems to be a blow off for a millisecond when I hit around 5,000 rpms and then continues to accelerate to the red line w/o a problem. It's as if it's hitting the red line at 5,000 rpms which it isn't
I have run a few bottles of Tectron thru the system (actually only one).
This never happened in my 2000 vert with 6 speed.
Any ideas/suggestions??
thank you!
I have noticed that with the traction control off during spirited acceleration, in first and second gear, there seems to be a blow off for a millisecond when I hit around 5,000 rpms and then continues to accelerate to the red line w/o a problem. It's as if it's hitting the red line at 5,000 rpms which it isn't
I have run a few bottles of Tectron thru the system (actually only one).
This never happened in my 2000 vert with 6 speed.
Any ideas/suggestions??
thank you!
Race Director
Joined: Dec 2013
Posts: 12,501
Likes: 3,627
Nannies still on in Track mode, so on that note, hold the TC button down for 5 second to turn all the nannies off to make sure that it not one of them kicking in when you hit around 5K that is pulling the motor back.
Next, as you hit around 5K, your at the end of the torque climb curve, and then is a matter of the engine rev'g out on HP climb curve alone.
Gm Semi tries to lean out the engine to keep the HP curve climbing steady upwards, but it does not lean out fuel out enough to keep the HP curve steady climbing instead, and the HP climb tends to go flat at 5K to 6.2K, which you are feeling instead.
So with a stock tune, the last 1K of rev tends to feel like you are just pushing the motor past red line from 5K on since there is not much of a linear increase in HP from about 5K on, and with a tune to allow the motor to lean out the needed amount instead to keep the HP climbing hard to Red line (pick up about 15hp more from 5K to 6.2K), you will find that you bounce off the rev limiter with out any hint of flat end of revs from 5 to 6.2K that the factor tune has instead.
Simply, what your are feeling is the stock tune, and GM did the tune so you would not be bouncing off the rev limiter every time you pushed the motor to red line. With a tune, the car is going to pull hard to red line instead, and trust me, until you get used it, you will be bouncing off the rev limiter by not shifting soon enough instead.
And to note, is not only the fuel air mixture that gets corrected, but the TM that gets reworked, since GM is using it to pull HP back to try to save the drive line instead.
So with the fuel and timing cleaned up, and the TM not hobbling the motor anymore, car will feel like it now has about twice the amount of power that is did before. Granted that you are only going to gain around 15hp on a stock motor tune, its the car no longer crippled by the TM and being able to put all the power through the drive line 100% that makes the huge difference instead.
Next, as you hit around 5K, your at the end of the torque climb curve, and then is a matter of the engine rev'g out on HP climb curve alone.
Gm Semi tries to lean out the engine to keep the HP curve climbing steady upwards, but it does not lean out fuel out enough to keep the HP curve steady climbing instead, and the HP climb tends to go flat at 5K to 6.2K, which you are feeling instead.
So with a stock tune, the last 1K of rev tends to feel like you are just pushing the motor past red line from 5K on since there is not much of a linear increase in HP from about 5K on, and with a tune to allow the motor to lean out the needed amount instead to keep the HP climbing hard to Red line (pick up about 15hp more from 5K to 6.2K), you will find that you bounce off the rev limiter with out any hint of flat end of revs from 5 to 6.2K that the factor tune has instead.
Simply, what your are feeling is the stock tune, and GM did the tune so you would not be bouncing off the rev limiter every time you pushed the motor to red line. With a tune, the car is going to pull hard to red line instead, and trust me, until you get used it, you will be bouncing off the rev limiter by not shifting soon enough instead.
And to note, is not only the fuel air mixture that gets corrected, but the TM that gets reworked, since GM is using it to pull HP back to try to save the drive line instead.
So with the fuel and timing cleaned up, and the TM not hobbling the motor anymore, car will feel like it now has about twice the amount of power that is did before. Granted that you are only going to gain around 15hp on a stock motor tune, its the car no longer crippled by the TM and being able to put all the power through the drive line 100% that makes the huge difference instead.
Thread Starter
Pro
Joined: Sep 2010
Posts: 707
Likes: 0
From: Murrysville PA
Nannies still on in Track mode, so on that note, hold the TC button down for 5 second to turn all the nannies off to make sure that it not one of them kicking in when you hit around 5K that is pulling the motor back.
Next, as you hit around 5K, your at the end of the torque climb curve, and then is a matter of the engine rev'g out on HP climb curve alone.
Gm Semi tries to lean out the engine to keep the HP curve climbing steady upwards, but it does not lean out fuel out enough to keep the HP curve steady climbing instead, and the HP climb tends to go flat at 5K to 6.2K, which you are feeling instead.
So with a stock tune, the last 1K of rev tends to feel like you are just pushing the motor past red line from 5K on since there is not much of a linear increase in HP from about 5K on, and with a tune to allow the motor to lean out the needed amount instead to keep the HP climbing hard to Red line (pick up about 15hp more from 5K to 6.2K), you will find that you bounce off the rev limiter with out any hint of flat end of revs from 5 to 6.2K that the factor tune has instead.
Simply, what your are feeling is the stock tune, and GM did the tune so you would not be bouncing off the rev limiter every time you pushed the motor to red line. With a tune, the car is going to pull hard to red line instead, and trust me, until you get used it, you will be bouncing off the rev limiter by not shifting soon enough instead.
And to note, is not only the fuel air mixture that gets corrected, but the TM that gets reworked, since GM is using it to pull HP back to try to save the drive line instead.
So with the fuel and timing cleaned up, and the TM not hobbling the motor anymore, car will feel like it now has about twice the amount of power that is did before. Granted that you are only going to gain around 15hp on a stock motor tune, its the car no longer crippled by the TM and being able to put all the power through the drive line 100% that makes the huge difference instead.
Next, as you hit around 5K, your at the end of the torque climb curve, and then is a matter of the engine rev'g out on HP climb curve alone.
Gm Semi tries to lean out the engine to keep the HP curve climbing steady upwards, but it does not lean out fuel out enough to keep the HP curve steady climbing instead, and the HP climb tends to go flat at 5K to 6.2K, which you are feeling instead.
So with a stock tune, the last 1K of rev tends to feel like you are just pushing the motor past red line from 5K on since there is not much of a linear increase in HP from about 5K on, and with a tune to allow the motor to lean out the needed amount instead to keep the HP climbing hard to Red line (pick up about 15hp more from 5K to 6.2K), you will find that you bounce off the rev limiter with out any hint of flat end of revs from 5 to 6.2K that the factor tune has instead.
Simply, what your are feeling is the stock tune, and GM did the tune so you would not be bouncing off the rev limiter every time you pushed the motor to red line. With a tune, the car is going to pull hard to red line instead, and trust me, until you get used it, you will be bouncing off the rev limiter by not shifting soon enough instead.
And to note, is not only the fuel air mixture that gets corrected, but the TM that gets reworked, since GM is using it to pull HP back to try to save the drive line instead.
So with the fuel and timing cleaned up, and the TM not hobbling the motor anymore, car will feel like it now has about twice the amount of power that is did before. Granted that you are only going to gain around 15hp on a stock motor tune, its the car no longer crippled by the TM and being able to put all the power through the drive line 100% that makes the huge difference instead.
I know a good tuner in my area that I will see the first chance I get.
