the TD04 is a massive downgrade to the VF52.


this is what happens when people are obsessed with numbers. i dont know how you can think a TD04 benefit you over a VF52 because it spools faster. the TD04 spools faster because its a smaller turbo, not because it is magic. just because a turbo spools faster doesnt mean it makes more power better and faster. there are dozens of other factors to consider. you could even get a bigger turbo than a VF52 and have it spool faster if you know how to shop for turbos.

this obsession people have with numbers and figures these days amazes me. "ohh man i gotta have XXX with XXX and as many XXX as i can."

 

My goal isn't more power per say. I just want 15-17psi alot sooner than i get full boost now. What would the characteristics be like on a 2.5?

 

15-17 psi doesnt matter. full spool means nothings. just because the turbo can pressurize to 15psi, doesnt mean its moving any more air than a larget turbo pushing 10psi. how much air is the turbo moving? whats the A/R? whats the exhaust housing side? hell something as simple as header wrap can increase spool...

not trying to insult you, but you need to learn a whole lot about turbo's.

heres some good info to get you started: https://www.turbobygarrett.com/turbobygarrett/choosing_turbo

a TD04 is way to small for a 2.5, which is why they stopped using it in 2008.

a good example of what im trying to say is this: a twin scroll spools slower than a single scroll, but a twin scroll provides more torque at low-end thus propelling you faster than a single scroll turbo thats spools faster. now i know youre not asking about twin scroll setups, but this is just an example of how spool isnt everything.

 

The TD-04 on my 08 wrx did not spool noticeably faster than the vf39 (same turbo as vf52 with different compressor outlet) I just bolted on. I'm reaching full boost right now well below 3500.

By the way, the TD-04 will be a HUGE horespower drop as others have said.. and that's a drop everywhere in the power band. The VF-39 with supporting mods PULLS nicely even well below target boost... like 2600+ rpm range... whereas the TD-04 did not.

My car picked up almost 60HP from the turbo upgrade... so you can expect a similar drop. Please note there were other mods done to add to this figure at the same time like my Water to Air Intercooler setup.

 

BTW, the better way to get faster spool would be an unrestricted downpipe, less restrictive intercooler and a good tune.

However if you do choose to go with TD-04 for whatever reason, then yes, they should be direct bolt on but you will need a tune.

I'll sell you mine!

 

You're going about it wrong. The '08 WRX TD04 is bolt on (and only the '08 version), however it's a huge drop in power. A +/-50 whp drop at stage 2 on pump gas. If you want faster spool you need to start looking at less restrictive exhausts, better boost control, and tuning.

 

Let me be the one to tell you that the TD04 turbo is horrible. I have it screaming to hit 17-18 pounds and can only get 238 at the wheels... thats with a full uppipe back exhaust on stock headers, big injectors, fuel pump, and full intake, and thats at like 4400 RPM. The top end on this turbo does not exist. you get awesome pull until 47-4800 then it drops like a stone. and if you don't use flat foot shifting youll hit boost cut between each shift (extreme boost spike on these turbos) and you'll run stupid slow times (if you go to a track). not to mention tuning it is a nightmare at those numbers, the wastegate is so small i was getting wastegate range codes (limp mode as well) all the time until he dumbed it down by around 10whp. if you like cool spool noises and power loss in the upper 2,000rpms its a great idea. I will trade you straight up my td04 (08 wrx) for your vf52 though. hey just throwing it out there.
Oh and my redline boost target is around 11psi i think just so you know what you're looking at.