Turbo sizing and spool question
 

So here's the deal,

I purchased and 04' S2000 a few months ago and I am interested in turboing the car. My previous car was also turbo'd (unfortunately totaled) and I was able to pull most of the important pieces from it, here is what I currently have:

Garrett GTX0376r
Precision Wastgate (39mm)
Tial Q BOV (50mm)
ID1000 injectors (came from a Subaru not entirely sure if that matters)
Flex fuel kit

My goals for this car is to make 550whp - 600whp on e85. Ideally I would like the turbo to spool at around 5k. I just prefer the "experience", if you will, of bigger\laggier turbo setups, I also drive about 100 miles a day all highway so cruising out of boost is ideal. I've looked at a lot of threads but still don't have a great idea of what spool times look like. Right now I'm looking at either a gtx3582r or precision 6266, they are both more than capable of supporting the HP and seems to produce good power at reasonable boost levels. It would be nice to save a few grand a go with turbo I already own but I'd rather get it right the first time. I'm sure these thoughts are all over the place so feel free to call me out on being stupid :urstupid:


TLDR: Would like a turbo that hits full boost at around 5000rpm, currently have a gtx3076r but unsure if it will A) will spool that late B) support 550-600whp comfortably

My car has a GTX3076R series 2 with 1.01ar. It is great but sometimes I wish I had something slightly bigger that really gave me that experience.
I think you need to aim for 650 to get the experience you're talking about, what about selling yours and buying a new GTX3576R with 0.82ar ??

Just FYI, ~500hp is pretty cheap to obtain, once you go above that power limit you have to start spending a LOT more money to get to the higher power levels...like a twin disc clutch, considerations for dual fuel pumps ect.
A 6266 is way over kill for 550-600 imo. A 3576r is more reasonable. I had a PTE 6062bb..it spooled at 4500ish

Every setup is different, but here's mine for reference

GTX3576r 1.06 A/R
1200cc injectors
620/480 on E85 @ 16psi (spiking to 19psi)
full spool is ~4200-4500rpm

I have contemplated going with a smaller turbo for quicker spool as my setup feels laggy....can't imagine wanting more lag

"GTX3576r 1.06 A/R" Why not swap it out for a 0.82ar?

Injectors are being sold and will buy 1300cc's. The spool has more to do with the way I drive the car most of the time, I don't want to be in boost when just cruising, only when I want to be. My old setup had taller gears (4.10s to 3.73s) and a laggier setup(hit full boost at around 4100 but redline was 7500), it was ideal for me and something I would like to mimic with this build, just with more hp.

You make a good point about using the wastegate to regulate spool, I hadn't though about that. My initial thinking was just to handle later spool with a bigger turbo and have the added bonus of more power.

Manifold and other components I'm still undecided, but I have some time to get that sorted out, suspension and more stopping power are first up.

Wow, that's pretty much exact what info I was looking for, gtx3576r sounds like what I want. You're right 5k may be overkill, I was initially thinking cruising in 6th I'm generally at 4000rpm so anything later than that is what I want but the combo you have looks to accomplish that and make damn good power doing so. Thanks!

Yeah, 3576r seems to be what I'm looking for, which was something I hadn't considered before now.