60% throttle faster than full throttle in first - why do you think that is then?
 

I have found that in first gear, when accelerating hard, I get a better continuous acceleration with the throttle at about 2/3 open than at full throttle.

At full throttle I find that the car does not pick up at around 3000 - 4000 rpm, it sort of hesitates, and then the power comes in hard.

With 2/3 throttle it flies off with no hesitation and feels much better.

2nd gear up, full throttle is great but not first gear - got any ideas.

i'm guessing it may be spark related....

Car is a MY94 WRX

It could be that it does not allow the turbo to overboost or surge. As the rate of rise of gas flow is very high compared to the rate in higher gears. Possibly talking bull but it seems reasonable

You may find at full throttle the greater airflow is causing the map to run higher on the load scale and hence pull timing.

Your probably running alot more ignition advance at 2/3rds throttle

The map has to cater for all instance, in all gears.
Full throttle in 5th would need alot of timing to be pulled in certain area's to prevent detonation.
So in the lower gears you suffer the consequence of this.

So I have to work around it then? I can do that but is is quite hard to judge the time to open the throttle from 2/3 to full. Mind you, at 2/3 in first I find I hardly need full throttle at the top of the rev range, may as well get into second asap.....

Would a Dawes manual boost control help in any way?

One thing that did occur to me just now, - when I changed my MAF sensor last year I noticed much better pick up in first. Could a slightly slow reacting MAF cause this issue.

i still have the old one (which was working pretty well as far as I can tell (was removed and replaced to fix another problem)), would it be worth cleaning it and trying it out?

what percentage does the tps show on the select moniter?

I have no such fancy equipment,,,,