Anyone here has run both on their tegs?
I am expecting T3 spool faster (4k rpm?) but T4 will give more hp at higher rpm?

Suggestions?

 

they will both spool up about the same ( couple 100 rpms difference) but the t04 compressor will give much better top end

 

i had a t3 t4 not sure what the specs were but i had full boost 7psi at 3200 rpms.
pretty much any t3 t4 can spool fast if you get the right wheel

 

^sounds like it had a stage 1 wheel

 

Does turbo lag depend only on the A/R of the turbine side or also on the compressor side?

 

People usually look first at the wheel diameter, wheel trim and exhuast housing A/R when trying to reduce turbo lag.

You could also add CHRA (i.e. whether it's ball or journal bearing), turbo location (underhood or at the end of the tail pipe), engine size (e.g.. a 1.6L is almost too small for a T3/T4) and design (e.g. T vs GT Technology).

There are other considerations also, but this pretty much covers all the bases.

Rod Short
Sales Manager
Precision Turbo

 

So do you think T3 vs. T3/t4 make any difference at all on turbo lag?

 

combination of everything!
Including:
a/r
trim
compressor housing
wheel stage
bearing (journal vs. ball)
In just one turbo you can have literally hundreds of options

keep reading and searching though I've seen you post a lot in the FI forum when these things can be searched

http://www.beesandgoats.com/bo....html
http://www.cse.uconn.edu/~yele....html
http://home.mn.rr.com/keebler65/honda/