Power Loss

[jman1200]

I recently switched to my 93 octane tune and added 94 oct fuel. Decided to do a few 0-60 street runs using the Torque app to measure them.
I found that when I try launching it between 2-2.5k rpm with the traction control off, there is a sudden loss of power after the wheels spin. I do not hear the engine revving so something is cutting it off. This doesn't happen when I do WOT's starting at idle speed.
I read that that can happen if there is a boost leak. Already checked the reference lines at the top and they are not loose.

I checked YouTube how to check for boost leaks and found a few videos where they cap one of the exhaust tips and blow air through the other one while spraying soapy water on the intake and turbo hardware. Wouldn't this potentially blow debris from the exhaust system into the cylinders? Is there a better way to do it without buying expensive tools? What else should I check?
I also have not been able to go below the 5 second mark so something is not right (or the torque app is not accurate).
Thanks in advance.

 

[SM105K]

I recently switched to my 93 octane tune and added 94 oct fuel. Decided to do a few 0-60 street runs using the Torque app to measure them.
I found that when I try revving it between 2-2.5k rpm with the traction control off, there is a sudden loss of power after the wheels spin. I do not hear the engine revving so something is cutting it off. This doesn't happen when I do WOT's starting at idle speed.
I read that that can happen if there is a boost leak. Already checked the reference lines at the top and they are not loose.

I checked YouTube how to check for boost leaks and found a few videos where they cap one of the exhaust tips and blow air through the other one while spraying soapy water on the intake and turbo hardware. Wouldn't this potentially blow debris from the exhaust system into the cylinders? Is there a better way to do it without buying expensive tools? What else should I check?
I also have not been able to go below the 5 second mark so something is not right (or the torque app is not accurate).
Thanks in advance.

It is cutting power? I know if I launch at too high of an rpm tq management takes over and literally shuts the power off to save itself.

 

[jman1200]

I don't recall it getting that high but honestly was looking for cops and not paying attention to the tachometer. By ear, it was not.

 

[SHOdded]

Have you allowed time for the PCM to relearn the tune? Have you checked the piping under the appearance cover/atop the intake manifold? Checked codes in the PCM?

Always start with the basics when it comes to troubleshooting. It is tedious, but saves unnecessary headaches.

 

[jman1200]

How much time would you say its required? I'm close to a week and full tank of gas now.
I checked the piping at the top and nothing looks out of place. Haven't checked around or under.
Yes, no codes.

 

[b4black]

I just uploaded an unleashed 93 tuned and experienced the same thing. Stock, if I stood on the brake and gas together, it would sit at 2500 all day. With the tune, when I got to 3000+, everything went bonkers and it barely ran. After about a minute, it was OK and I haven't tried again since.

I'd rather it sit at a lower RPM then shut itself down......

 

[SHOdded]

Unless you upgrade brakes and tires, the brake launch is typically more in the 2000-2200 rpm range.

j, 100-200 miles of driving is typical, but if you are saying there are NO codes at all, ... I would do a hard KAM reset, unhook the neg battery cable for 40+ minutes, let it relearn. Sometimes the KAM reset done by a tune upload is not sufficient. If you still have issues after, go back to stock, and reload the tune. Happens from time to time that the tune does not "take" on the first try.

Also, if you are turning and goosing the pedal at the same time, the nannies will cut you off.

 

[jman1200]

I just did a couple of runs following @SM105K recommendations.
Brake launched, TC off:
2200 rpm - power loss at around 4000 rpm, as soon as the wheels gain traction again. Tried twice with the same results.
1800-1900 rpm - some wheel spin on 1st and 2nd gear, no power loss. Was able to hit my best 0-60 mph time so far at 5.09 secs.

So, it has to be TQ management as stated. Not sure why it is set so low so I'll reload the tune sometime this week as @SHOdded suggested and try again.

Still puzzled why I can't easily get below the 5 second mark considering the upgrades I have on.

 

[SHOdded]

What tires and tire pressures are you running?

 

[jman1200]

Oh man, the pressure question again.... be back in a minute.

 

[jman1200]

Ok, measured the pressure, first time in the past year. It is low, 29 at the front and 30 at the back. Need to get this up a bit.

275/40 20 Goodyear Eagle's

 

[SHOdded]

Approximate tread? I am guessing here, but traction seems to be an issue. Those with ACTUAL experience will correct me I am sure

Also, softer sidewall tires need more psi to launch better (effectively creating less sidewall flex).

https://shoforum.com/index.php?threads/my-slo-sho-lms-tuned.137759/page-2#post-1493139

 

[ridered74]

I wouldn't put a ton of stock into it if you are strictly going off torque, I have found it to be wildly inaccurate on my car. Do a datalog, and look at the time when you are at 0 mph, and then look at the time when you first hit 60 mph.

That still isn't 100% accurate, but it is much more accurate than torque.

 

[marius883]

Make sure you check the hose that goes to the intercooler as well, mine had a massive crack in it, causing a huge boost leak.

 

[Eric Morris]

Put some drag radials on it.

 

[jman1200]

Still puzzled why I can't easily get below the 5 second mark considering the upgrades I have on.

 

[SM105K]

Tire Pressure?

 

[jman1200]

35 psi

 

[SM105K]

Run her at 28 in the front and 35 in the rear and see what the new zero to sixty does.

 

[jman1200]

Run her at 28 in the front and 35 in the rear and see what the new zero to sixty does.

What are you getting?