Best Gear with Procharger

[Stangmang]

Hi all,


I drive a 2015 Gt, 6r80 car with a P1x running on an HO kit. Next mod will be a ported 18 mani. From what I've heard, there can be a slight tourqe loss down low on autos running 3.15 gear with the 18 mani. FYI, I don't track more than a couple times a year, so I'm not worried about what gear I cross the track in. My goals are to basically build a fun street car. I'd like to increase the RPM band a bit as the stock one made peak around 6200rpm, but I'd like keep some punch down low.


Would jumping to 3.55 gears be a good switch to help spin up the prochager maybe and get it into boost? I always felt the 3.15s were a bit lazy. I also plan to add headers and pulley down to make around 10psi after the mani.


Thanks!

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[GreenS550]

I put a p1x ho kit on my 2018 with 355 gears. Then went to higher boost, BAP, injectors etc. It ruined the drivability of the car. Now, mind you, my 1st gear is somewhat lower than yours, but not alot. No traction, etc. Just worthless when you accelerated it.
There are some real Procharger experts on this forum. I am sure they will chime in. But, my first thought is the 355 is too much gear. If you want more low end torque/throttle response, I would look at a smaller pulley, etc. The HO kit is great for drivability but fairly low boost.
I would do the pulley, injectors before a gear or even the '18 manifold. It has been my experience that the different intakes have more advantage when NA. The HO kit on my '18 made 535 rwhp at 6.5 psi boost. Once I put a pulley and injectors on it the power was tremendous. I never dyno'd it after that by my guess was 650 rwhp. A gear in that range was overkill.
Good luck on your pick.

 

[SolarFlare]

depends on what you want to do. I like 3.55s.

 

[Stangmang]

I put a p1x ho kit on my 2018 with 355 gears. Then went to higher boost, BAP, injectors etc. It ruined the drivability of the car. Now, mind you, my 1st gear is somewhat lower than yours, but not alot. No traction, etc. Just worthless when you accelerated it.
There are some real Procharger experts on this forum. I am sure they will chime in. But, my first thought is the 355 is too much gear. If you want more low end torque/throttle response, I would look at a smaller pulley, etc. The HO kit is great for drivability but fairly low boost.
I would do the pulley, injectors before a gear or even the '18 manifold. It has been my experience that the different intakes have more advantage when NA. The HO kit on my '18 made 535 rwhp at 6.5 psi boost. Once I put a pulley and injectors on it the power was tremendous. I never dyno'd it after that by my guess was 650 rwhp. A gear in that range was overkill.
Good luck on your pick.

Serious question. Is the 10r80 to a 6r80 car comparable when talking gears swaps? You already have 10 gears that roll through pretty quick. I am running 8psi at 533whp and will be adding a ported 18 mani I already have.

What pulley did you down size to in order to increase such a substantial amount? How much psi? My understanding is that 10-11 is pretty much it on pump gas..I always thought each pully drop was only good for 15 to 20whp. Did you increase injector and go e85?

 

[Stangmang]

depends on what you want to do. I like 3.55s.

I'd like to gain some pep down low around town, and get into the higher rpms quicker to spin up the procharger. Does this make sense?

 

[cbrtrx]

3.55s work very well on a 6r80 car.

 

[80FoxCoupe]

Id go 373 personally.

 

[Stangmang]

Id go 373 personally.

On a 6r80 car?

 

[80FoxCoupe]

On a 6r80 car?

Yes absolutely

 

[GreenS550]

Serious question. Is the 10r80 to a 6r80 car comparable when talking gears swaps? You already have 10 gears that roll through pretty quick. I am running 8psi at 533whp and will be adding a ported 18 mani I already have.

What pulley did you down size to in order to increase such a substantial amount? How much psi? My understanding is that 10-11 is pretty much it on pump gas..I always thought each pully drop was only good for 15 to 20whp. Did you increase injector and go e85?

It's not just the pulley. It's the larger injectors, bap and tune. Prochargers tune is quite conservative and it's 50 state legal with a minimum 91 octane. And first gear is just slightly higher in the 6r80. You're going to have a custom tune using that 18 manifold.
And you asked an opinion. I wouldn't do the gear. My car was tuned for 93 by pbd. Contact your tuner. They are your best source for what you're looking for. My 15 had the 355 gears and in my opinion excellent for na but when I was fi, it was too much.

 

[80FoxCoupe]

373 if you want to get the most out of your setup.

 

[LSchicago]

Depends on the tires you are willing to run. If you are not willing to REALLY step up your tire game, keep the 3.15's. I'm sticking with my 3.55's, because I have BIG Street R's.

 

[80FoxCoupe]

Depends on the tires you are willing to run. If you are not willing to REALLY step up your tire game, keep the 3.15's. I'm sticking with my 3.55's, because I have BIG Street R's.

You make more power than the OP, and also have a 10r80.

The OP's setup is the mildest boosted combo possible. Traction from a dead stop on anything short of a drag radial should be a problem now. It doesn't sound like he is trying to make hits from a dig on a regular tire. Slow roll im sure its fine. Ive ran 315, 355 and 373 with a procharger, with a 6r80 from 600whp all the way to 1300whp. Based on the OP's original post, 373 would be my recommendation.

 

[Stangmang]

Depends on the tires you are willing to run. If you are not willing to REALLY step up your tire game, keep the 3.15's. I'm sticking with my 3.55's, because I have BIG Street R's.

I am running 285x19 Michelin pilot sports in the back. No tracking, this is just a fun street car. How do you like the 3.55 gears? Going from 3.15 I have to do the whole pumpkin I believe.

 

[80FoxCoupe]

But then again everyone has a different approach. I am of the mindset conservative changes yield conservative results. OP sounds like a limited number of mods is where he wants to be. The more aggressive gear will give him the best bang for the buck based on that.

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