Qd32 turbo sizing

[Dirty Trix 2]

Since i need to buy a new turbo anyway, would there be much difference in where the boost comes in between a 0.48 A/R and a 0.60 A/R?

I know the boost will kick in later, but how much difference?

 

[Rabbid-chop]

Yes it will make a difference, but what makes a bigger difference is the size of the turbine wheel, ie; a big turbine wheel with small A/R will flow more and spool later than a small wheel with a big A/R. Other things affect things too such as compressor trim and size.
What turbo are you looking at getting. Specs? I have played around with a couple different turbos on my ZD30 so might be able to give you a guestimation on how it will go.
Im going to go ahead and say the stock turbine housing would have been 0.48 A/R or smaller.

 

[Dirty Trix 2]

Stock on the Td27t was, for my example at least, a Garrett tb25. 0.48 A/R on the compressor and dunno, believe 0.64 on the hot side.

I was tossing up a few different options because
1) original turbos are bloody expensive (about Au $900 for a mamba copy and $2000 for a genuine Garrett.
2) they're very old tech, even the tb25 type I had.
3) they do run out of puff up top.

I could have got a 0.42 or 0.60 A/R compressor for about $320 or $200 respectively and still had a watercooled tb25.

A gt2860 would also be in that mid 300's price range but i know some of the 2800's have different wastegate bolt pattern.

In the end I've just ordered a new core for the 452162-1 I had. Save stuffing around with changing hoses for different turbos, hasn't set me back too much money (about $160) and it should produce good boost down low which is even more important for the even slower revving QD32.

I'm mainly after the power for offroad and towing my camper van anyway.

But any feedback on it would be interesting because, for a few hundred bucks, I might have a play later.

 

[Rabbid-chop]

Compressor housing A/R doesnt really make any difference, but the size of the wheel does, especially the inducer.
Hot side A/R makes a big difference in spool. But again, the size of the wheel makes the biggest difference.
2860 might be too big, i was running the 2554r which is all round smaller than that but much bigger in the turbine than stock, with a .42 hot side, and it pulled like a train up top but didnt get full boost until about 500-600rpm later than stock. Made up for the lack of boost down low just by freeing up the exhaust so much down low, but was blowing fuel smoke which wasnt a good look. Ive since gone to a TD04 which is similar size to stock, just a touch bigger, and it boosts up quicker than stock, and has a touch ore up top.
You want to stick with something near stock size hot side and maybe go a slightly bigger/better compressor if you want heaps down low as well as more up top.