So I had a bad idea....
 

This bad idea was to buy/build a turbo system around a t3/t4 and now that just about all the bugs are worked out I am thinking I want to try to remedy the slow spool thing. I really don't want to cut my flanges off and weld on new ones, so I was thinking perhaps there was a smaller turbo I could bolt up. I was also thinking I could advance (or was it retard) the timing a bit to get a faster spool. The system is on a 1.8 (which will become a 2.0 some day) running a ms. So what do you guys recommend? Thanks!

I think that was a bad idea... There must be some smaller turbo that will bolt up, though I don't have a clue what that might be.

What kind of power are you wanting to make? Are you going to be drag racing? Track racing? Normal street driving? What is your intercooler setup like? What is your downpipe like? How about the rest of your exhaust? Are you using a boost controller? What kind of wastegate?

We need more information man. You have told us nothing.

Look into a garrett t3 super 60, .48 turbine for best spool. I have the same turbo and my setup spools very well. It's the same bolt pattern as your turbine so it should bolt to your manifold no problem, downpipe I'm not sure about.

My vote is for a TD05-16G, very happy w/ mine.

My bad...she has 3" turbo back, a large enough intercooler to keep the carge temp down, ms ecu that also acts as the boost controller, and the wastegate is a tial. Not lookin to have her be a dyno queen sooooooo I would say street driving first and autox second. Will a TD05-16G be a direct swap?

You're still not giving enough information... exactly what do you want? When do you want to spool? How much power do you want to make? Is torque important? What psi are you comfortable pushing? What manifold are you using? We need some numbers.

It sounds like you're more of a top-end kind of guy. If you're looking in the 250-300whp range, I'd get a GT2860 from ATP with their T3 turbine-housing option. Call and ask them about compatibility.

What I want is a smaller turbo that will bolt in place of my t3/t4 that will spool faster (currently spool at about 4k and I want to spool at 2k) and is not very responsive. I would like a broad power band rather than peaky (for street driving and autox). As of present I have 185whp/165tq @ 7psi and am willing to turn it up to 12 psi after a good tune (would really like to make it above 200whp). I am running a racing mazda upturned exhaust manifold and have 550cc injectors with a stock fuel pump and rail. I am really thinking about the 16g but still wondering if it would directly bolt on...

Do you know the specs on the particular T3/T4 combination that you have? Going to a smaller turbine in the T3 family may help. Using a smaller T4 compressor may help. All depends on what you have on the car. "T3/T4" covers a *lot* of turbo combinations. You need to figure out exactally what you have or none of this will be any help....
--Alex

Recently there was a thread by DVCN who runs a "T3/4" turbo and reported spooling under 4k. You may want check that thread and compare setup.

First two things I thought of when I read this thread were:
1. Tune
2. Exhaust setup

You said you are running 185hp without a good tune. Part of tuning is going to be advancing timing which is going to impact spool range. We need to know your DP diameter, cat/catless, muffler, ect...

If you are truly committed to changing to a smaller turbo, remember that many of them are plumbed for both oil *and* water. 16g is not going to bolt up to that exhaust manifold plus it's also going to need water AND most DSM style 16g turbos have a flange style compressor outlet which can require an additional adapter.

OK, checked the turbo and the compressor is a 60 and the turbine is a .82, on my way home I checked to see exactly when I was getting full boost from a stop and it was approx. 4500rpm's and under load 3200-3700rpm's (with a lag time of about 3-5 seconds). When I had it tuned it was done at a shop in hawaii and they knew/know what they are doing so I think it is spooling as fast as it can in current condition. I forgot to post the rest of the spec's last time, sorry about that. it is 3" turbo back with a tial external wastegate and megasquirt controlling boost. Intercooler fills up my front bumpers mouth so it is large enough to keep charge temps low (no real science behind that claim though :). The car is also plumbed for oil and water and I somehow ended up with lots of fittings so I think I can accomidate if there was a need (hopefully not though). I was lookin at turbonetic's website and I think I could get something like .36 40?