21 Locked ECM w/ Catless DP. Feels Slower

[slobra300]

I have a 21 locked ecm supra and recently installed a catless DP. I knew I was going to get the CEL which I did and I knew the gains would only be 10-15whp without tune but I wanted the additional sound and was just going to enjoy the small gain in HP while I wait on the ECM to be unlocked but the car seems a little slower now. I've only put about 50 miles on the car so perhaps the ECM is still learning the new conditions? Car is definitely not slow but it did loose some snap, seems to take longer through the gears. Everywhere I read, tuners said it is safe to do with the only downside being the additional CEL. Can anyone comment on this?

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[Munkeeboi]

change your screen name to Fastbra300...hahah

Might be the ECU, but also might be in your head since the car sounds different. also, running with the CE light is safe, but your gains might be somewhere else in the performance band without a tune.

 

[slobra300]

haha.. Funny enough, that name dates back to highschool where I had a 96 GT that looked like a Cobra so I was nicknamed Slobra...

Good point on the sound impacting my perception. I really just need to put some more miles on the car for a better opinion.

 

[Supercompact]

I have a 21 locked ecm supra and recently installed a catless DP. I knew I was going to get the CEL which I did and I knew the gains would only be 10-15whp without tune but I wanted the additional sound and was just going to enjoy the small gain in HP while I wait on the ECM to be unlocked but the car seems a little slower now. I've only put about 50 miles on the car so perhaps the ECM is still learning the new conditions? Car is definitely not slow but it did loose some snap, seems to take longer through the gears. Everywhere I read, tuners said it is safe to do with the only downside being the additional CEL. Can anyone comment on this?

Did you ever get this figured out?

 

[Batlwagn]

A catless downpipe you'll lose bottom end because of the loss of backpressure. A proper tune will fix it because it would adjust the boost targets to compensate for the lost back pressure.

 

[MisterSkiz]

A catless downpipe you'll lose bottom end because of the loss of backpressure. A proper tune will fix it because it would adjust the boost targets to compensate for the lost back pressure.

That is not correct at all - opening up the exhaust will allow the turbo to spool faster.
The whole "losing backpressure" is nothing but a old wive's tale on today's cars.

What is most likely happening is the CEL is putting a car into limp mode of some type.
I would suggest to the original poster to do some logging and see what the timing, etc is; then clear the CEL and begin logging again and compare values.

As his ECU is not able to be tuned, his only option to avoid the CEL is to go back to stock, or to use some type of device that pulls the 02 sensor away from the pipe and through a filter, such as below: https://www.amazon.com/Connector-Catalytic-Convertor-Catalyst-M18X1-5/dp/B097NZXQ42

 

[suicidaleggroll]

A catless downpipe you'll lose bottom end because of the loss of backpressure.

That's not a thing on turbo cars, the turbo itself will provide all of the backpressure you might "need". You want the exhaust restriction after the turbo to be as low as possible. Just google "turbo backpressure", literally every single match will tell you that it's bad and why.

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