25 boost clutching

[JH@CM]

Hi folks,

I've found my 25 boost to run higher RPMs with stock clutching than previous iterations/tunes. I do have a TRS power flow intake and a diamond s can, but otherwise stock for everything else.

Mostly riding 7000-9500ft, and seeing 8500-8600 regularly in the middle of the riding elevation. While this is far better than under rev, I wonder if anyone is having success changing weights to 78gr or 80gr from the stock 76gr that come on the high elevation build. OEM or aftermarket weights?

Dyno info tells us that 8350-8400RPM is a sweet spot for making power on these 840 turbos, so I'm curious to hear what people are doing aside from changing to full new clutch setups with different springs and helix.

 

[Ultrasauras]

Stock primary SPRING 165/310 change it to a 165 /300 or 165 / 290 spring they are cheap and will drop your max rpm

 

[Wheel House Motorsports]

The 25 mapping ans those 2 mods runs VERY well. Throwing 78s should pull you down to where you want to be. Def worth trying a set out.

 

[JH@CM]

The 25 mapping ans those 2 mods runs VERY well. Throwing 78s should pull you down to where you want to be. Def worth trying a set out.

Yeah, it's very angry! I'm likely to toss in some 78s if I can find some.

 

[Sheetmetalfab]

Yeah, it's very angry! I'm likely to toss in some 78s if I can find some.

I'm having good luck with the slp magnum force P22 weights.

 

[davesilb]

Hi folks,

I've found my 25 boost to run higher RPMs with stock clutching than previous iterations/tunes. I do have a TRS power flow intake and a diamond s can, but otherwise stock for everything else.

Mostly riding 7000-9500ft, and seeing 8500-8600 regularly in the middle of the riding elevation. While this is far better than under rev, I wonder if anyone is having success changing weights to 78gr or 80gr from the stock 76gr that come on the high elevation build. OEM or aftermarket weights?

Dyno info tells us that 8350-8400RPM is a sweet spot for making power on these 840 turbos, so I'm curious to hear what people are doing aside from changing to full new clutch setups with different springs and helix.

I installed 80 gram weights into my 23 boost as I run at 6-8000 ft and it stays right at 8300 and shifting seems to be right on. Took the 76 gram weights and installed them in the 9R from the 72's it had in it and it seems to be perfect for me now turning 8300 where before it was turning 8600. I might consider using a 120-300 spring at some point instead of the 140-320 to get the cuising RPM dowm a bit to help mileage

 

[Reddragon800]

Take a look at SRP (Seinen Racing Products). The best boost cluthcing for the best price in the market.

 

[JH@CM]

I might consider using a 120-300 spring at some point instead of the 140-320 to get the cuising RPM dowm a bit to help mileage

Good data points, thanks for sharing.

For high elevation configuration:
Stock boost spring is 165-310
Stock 9R spring is 140-330