I have a 1990 jap import TT. (manual )

 

The boost gauge goes from -7 to +7.

 

On full boost I'm getting about 6 psi.

 

Is this about right?

 

I've heard that normal boost is +9 psi?

 

Any comments?

 

Cheers.

 

Martin.

Your boost gauge reads mmHg, not psi.

Ahhhhhh, I see. I only bought the car yesterday and have only driven it about 6 miles.

 

Does the reading of 6 mmHg sound about right?

 

I'll look through all the manuals when I get home tonight.

 

All the best.

 

Martin.

+7 (x100mmHg) is approximately equal to 14psi

 

So reading +6 would suggest approx 12psi, although the gauges are notoriously inaccurate.

 

 

Normally boost would max out around 9 - 9.5psi, so it could be that your gauge is a little inaccurate , or that your boost has been raised a little.

Mines the same reading - the last mark before the end of the guage at full throttle.

same here, needle goes up to the last quarter on the positive side of the guage on full boost (if that makes sence? :D )

My stock mmHg gauge reads +7 regardless of what boost i'm running,weather i run 8psi or 10 or 14,or even 25psi(oops i think thats what caused my trouble:D )so never ever rely on it,use a good after market one,and take ya time to set it up,all three of my boost gauges(Kpa,Psi,mmHg,all read 0 at same time);)

Blimey, there's a coincidence!

 

1.9338 psi = 100 mm Hg

 

The 7 (x100 mm Hg) marking on the gauge = 13.5 psi

(stock wastegate should operate between 11 and 13 psi)

the 3/4 mark is 5.25 (x 100 mm Hg) = 10.15 psi

the 1/2 way mark is 3.5 (x 100mm Hg) = 6.768 psi

the 1/4 way mark is 1.75 (x 100mm Hg) = 3.38 psi.

 

Allegedly stock boost is 9 or 9.5 psi and safety boost of 7 psi BUT I have not been able to find any authoritative reference for this.

 

Cheers - Gio