im located in san jose area. can anyone suggest a relatively safe location to do a full 4th gear pull? i need to get some data logging done to check some figures. thanks!

 

Freeway pulls ftw.

 

just becareful.. cops at every where in the 408

 

Salt flats.

 

4th gear?!

 

Coulda sworn it was 3rd lol

 

3rd is for wrx. 4th for STI. Still looking! Pm if u want to keep it private! Thanks!

 

When there is little to no traffic, Yerba Buena to 101 north or south is what i've used in the past with 3rd gear pulls. I've also gone late evenings when the freeway has little to no traffic, slowed down and then pulled to redline. Use your judgement on safety/cops.

 

4th is for the old STis, where 4th was about equal to WRX 3rd. New STis with taller gearing and also much taller tires (245/40/18 vs. old STis at 225/45/17), 4th in 04-05 STi was pretty much the same as WRX 3rd for 02-05.

Ratios in the newer USDM 6 speeds are much taller, and 3rd is appropriate if you don't like frequently going 125 on public roads.

With stock tires:
7000 RPM on an 02-05 WRX in 3rd is ~99
7000 RPM on an 04-06 STi in 4th is ~101
7000 RPM on a 12 STi in 4th is ~124
7000 RPM on a 12 STi in 3rd is ~93

I use 3rd when road tuning 08+ STis. Finding room for 4th is difficult and usually not reliable in how often that much space will be available.

 

Slightly related question, is a slight uphill gradient going to affect the data log significantly?

 

Everything affects data logging

 

Thank you for this input. I was not too keen on breaking into triple digit speeds, at least not publicly.

More questions for you:
1. I'm not on stock tires. 255/40/18. Will this affect things?
2. You recommend 3rd gear for data log but 4 is recommended by Cobb. Can you elaborate or is it safety reasons?

Thanks again!

 

Third seems the most logical since you have slightly wider than stock tires..

 

4th will spool turbo earlier in rpm range. Top side should be aprox the same.

 

You want higher gears so things are happening more slowly and giving you more data points, but this is at odds with finding a place safe enough and long enough.