When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
just spoken with one of our well respected tuners regarding turbo choice and he’s got me thinking…I’m aiming for the 450bhp mark and I even know which turbo brand I’m going with..
Im thinking shall I get a 500bhp turbo and turn the boost down a little so it’s not ringing the neck out of it or should I get the 450bhp turbo (turn the boost up to 1.7 bar odd) and expect around the 450bhp mark? (I know there’s going to be lag in both situations)
how much different would the car drive in those scenarios? Thanks
My personal take would be; if I knew i'd be happy with 450hp forever, then I would go with a 450hp turbo, because there will be differences in spool time between a 450 and 500hp turbo (assuming they're both as well designed and effective as each other).
Also, if I had a 500hp capable turbo, but "only" made 450, then I think I'd also want to push it to 500 instead... To me, it'd feel like a waste not to make the 500, if the turbo was capable of 500 (not waste, maybe, but "suboptimal").
As to how a 450 vs 500hp turbo would drive, I have no idea, never had that kind of power in an Impreza, but I have had two cars make roughly low 300's: one with a td05-16g (crap fuel on purpose on this one), and the other with a hybrid td04. The td04 is _massively_ better than the td05 for this power for me, because the spool and response is so much better. If the td05 had made 350 instead of the 317 it made, it might have changed my perception, but the point is that if the bigger turbo was held back to 450, it would probably drive slightly worse than the actual "designed for 450" turbo.
Don't forget you're in rebuild territory too mate. Turbo technology has moved on massively and I'll be honest I've been left behind but have a look at this video.
My personal take would be; if I knew i'd be happy with 450hp forever, then I would go with a 450hp turbo, because there will be differences in spool time between a 450 and 500hp turbo (assuming they're both as well designed and effective as each other).
Also, if I had a 500hp capable turbo, but "only" made 450, then I think I'd also want to push it to 500 instead... To me, it'd feel like a waste not to make the 500, if the turbo was capable of 500 (not waste, maybe, but "suboptimal").
As to how a 450 vs 500hp turbo would drive, I have no idea, never had that kind of power in an Impreza, but I have had two cars make roughly low 300's: one with a td05-16g (crap fuel on purpose on this one), and the other with a hybrid td04. The td04 is _massively_ better than the td05 for this power for me, because the spool and response is so much better. If the td05 had made 350 instead of the 317 it made, it might have changed my perception, but the point is that if the bigger turbo was held back to 450, it would probably drive slightly worse than the actual "designed for 450" turbo.
Only you can decide
thanks for your reply mate….the specialist in question said the spool loss in the bigger turbo will be minimal (100 - 150rpm) but your ringing the neck out of the smaller turbo to make the numbers…I will probably go with the smaller one to be honest as I’m guessing it will be “punchier’ once the boost kicks in..
Don't forget you're in rebuild territory too mate. Turbo technology has moved on massively and I'll be honest I've been left behind but have a look at this video.
I’ve asked the question regarding rebuilding my vf35 and the turbo specialists has said you will get a maximum 40-50bhp which is certainly not shy but I’m after the 450bhp mark odd 👍👍
I’ve asked the question regarding rebuilding my vf35 and the turbo specialists has said you will get a maximum 40-50bhp which is certainly not shy but I’m after the 450bhp mark odd 👍👍
hope your good mate 👍
Sorry I meant rebuild like forged engine. Some have run 450bhp on stock internals and I've seen one blow a hole in a block but he was full sending it. YMMV
Who did you speak to about rebuilding your turbo, what were the costs quoted?
My old AET supplied GTX3071 was awesome for a single scroll. Really fast spool and made 450 with ease. It totally changed how the car drove over the previous SR40 it replaced. Because it spooled early and progressively it made the car predictable and easy to drive. I'd highly recommend that turbo to anyone looking for a solid 450bhp.
Sorry I meant rebuild like forged engine. Some have run 450bhp on stock internals and I've seen one blow a hole in a block but he was full sending it. YMMV
Who did you speak to about rebuilding your turbo, what were the costs quoted?
I'm in a bit of a rough situation, car got robbed
My bad mate, I thought you meant rebuilding the turbo 🤦🏻♂️
We all know it’s a lottery when tuning these cars, if my engine goes at 450bhp then so be it…lots of cars have probably went at a lot less power…I’m pretty sure my engine is healthy, it’s never been worked on by any back street garage and I will continue taking it to specialists for the important work so it’s in the Subaru gods hands….I phoned the turbo rebuild people who get mentioned on here, bellworthy etc…some don’t even rebuild them….can’t remember the price exactly but it was a good few hundred and not over a grand
**** regarding what happened to your car mate, hope your luck turns 👍
Come on tell us what turbo ! Lol
im in a very similar situation ( was ) I was torn between a 450 and a 500 turbo. I opted for the 450 after speaking with many tuners and knowledgeable people because I wanted driveability over pub figures. I backed all this up with supporting mods to fuel / air / cooling etc , I can’t tell you what it’s like as it’s still being built. I’d say if your happy with 450 then defo stick with the smallest turbo that will get you very near to that figure it will make for a quick and very responsive road car in my opinion.
I’m going for one of these beauties 😍…I asked the specialist who will be fitting all the parts for his opinion on turbo choice and he said this one…that will do me 👌
Am also in same boat tho too it’s taken me wile as I change my mind every few weeks lol also bin doing my research took the plunge today and ordered the MDX321V so will let you no we’re my power lands anywhere in 450 range and il be happy tho have other parts on order too so won’t be fitting until prob early march. Be nice to here from you once your car is mapped in and how you feel on your turbo
Last edited by Nrbg455; 13 January 2023 at 06:40 PM.
I previously bought a MD321T but didn’t end up fitting it. In order for it to fit the standard location, you need to shave the bell housing and remove a couple of irrelevant lugs off the block. I didn’t fancy doing that which is why I plumped for the GTX range. I presume this is still the case for the MD range.
Am also in same boat tho too it’s taken me wile as I change my mind every few weeks lol also bin doing my research took the plunge today and ordered the MDX321V so will let you no we’re my power lands anywhere in 450 range and il be happy tho have other parts on order too so won’t be fitting until prob early march. Be nice to here from you once your car is mapped in and how you feel on your turbo
This is the 500 hp turbo that never reaches 500hp lol, far better off with mdx 321t which will also never reach 500 hp but might reach 450hp and with better spool .
I previously bought a MD321T but didn’t end up fitting it. In order for it to fit the standard location, you need to shave the bell housing and remove a couple of irrelevant lugs off the block. I didn’t fancy doing that which is why I plumped for the GTX range. I presume this is still the case for the MD range.
md range is a non shaving turbo I've had experience , there is a choice of outlet depending on your choice of intercooler
10 January 2023, 09:26 AM
Turbo question
