Low-end Torque

[MoonDoogy-X]

I just got a new to me 2018 GT2. Love the car. When driving normally, which is like 99% of the time, I live below 2000 rpm. I noticed after installing aftermarket intake (aFe) and exhaust (mbrp pro) the car is feeling a bit sluggish in that range. I have to say, it is noticeably faster the othe 1% of the time . I was wanting to delete the secondary cats and maybe upgrade the fmic if I ever get brave enough to remove the front bumper. Now, I don't know if I should risk losing more torque down low.

I had a similar issue in my n/a v6 toyota after installing headers and was able to fix it with a custom tune that adjusted the vavles and ignition timing, fuel, and throttle. In the end, the car had a flattened torque curve and even better gas mileage. Is there a similar solution for the stinger that isn't just a throttle controller or cranks the boost constantly? Or preferable an non-computer mod that adds torque down low?

 

[Snowwhite]

it's usually lack of exhaust backflow that kills low end torque. I have an MBRP and I also like to torque my way through life below 2k rpm. I didn't notice a drop in torque when I installed it. you could probably get a tune, but unless someone has already done it with your setup (or similar), you'll have to work with a tuner (and your car) to get them to do that.

 

[Thomby]

I find it very hard to belief that you actually lost torque at 2000rpm. It may be that the gains higher up make the low end seem like it's fallen behind, but our turbos are very small and optimized to kick in very low -- peak torque is 13-1400 rpm.

Have you tried rolling onto the throttle from around 1000rpm and watching your gauge to see how boost builds from 1000-2500ish?

 

[Snowwhite]

I've experienced what OP is describing on naturally aspirated cars. On this boosted torque monster, no. I rarely use more than 1/4 throttle for my commute.

 

[Yves998]

That's not how it works on a boosted car. Losing back pressure = faster turbo spool = higher low end torque. You'll see Audi loses power and torque on catless sometimes but it's their ECU freaks out and limits the torque. Hence the car was going to making more torque before ECU said no.

All that you experienced is just mbrp droning at lower rpm where stock exhaust killed all the drone.

 

[MoonDoogy-X]

That's not how it works on a boosted car. Losing back pressure = faster turbo spool = higher low end torque. You'll see Audi loses power and torque on catless sometimes but it's their ECU freaks out and limits the torque. Hence the car was going to making more torque before ECU said no.

All that you experienced is just mbrp droning at lower rpm where stock exhaust killed all the drone.

I think that you're probably right. The sound of the exhaust makes feel like I'm giving it more throttle than I actually am. I installed secondary downpipes since I originally posted thins and my softshoeing was more noticeable then.

That said, for the record, in eco and comfort modes, under low load, below 2000 RPM, the car runs a vacuum, no boost. It least not enough to make positive pressure.

 

[Yves998]

I think that you're probably right. The sound of the exhaust makes feel like I'm giving it more throttle than I actually am. I installed secondary downpipes since I originally posted thins and my softshoeing was more noticeable then.

That said, for the record, in eco and comfort modes, under low load, below 2000 RPM, the car runs a vacuum, no boost. It least not enough to make positive pressure.

Our turbo is super small and exhaust manifold diameter is extremely tiny. Pre-turbo back pressure wouldn't be affected under this circumstance. That pre turbo back pressure almost is pita for hybrid turbos too.

 

[5tinger]

Most impressive about this car is the low rpm pull. The speed climbs and the rpms are at 1000rpm