Turbo Choices for ScoobieWRX

duncan · Post by **duncan** » Tue Jun 24, 2008 7:32 am

It was hitting 2.2 bar before on the old turbo Francis. You could wind the VF35 up more but I guess the limit of the gearbox strength holds you back from doing that at the moment.

ScoobieWRX · Post by **ScoobieWRX** » Tue Jun 24, 2008 7:37 am

My gearbox would surely explode if i go any more than that. It's already a bit suspect so i'll play safe.

By the way....do you know what the max safe limit on the VF35 is? I've been looking everywhere and not found a definitive answer on that as yet. I would like to experiment briefly :twisted: but i don't want to blow the turbo either

duncan · Post by **duncan** » Tue Jun 24, 2008 7:42 am

There is no such thing as a safe limit/defined limit for the turbos. It depends on so many things but they can be wound up to a fair bit more than you have at present. It will start running out of puff and end up super heating the air as it is out of its efficiency zone though if you take too many liberties.

I would have though 1.5 bar would be fairly straightforward. Do you have a top mount still ?

ScoobieWRX · Post by **ScoobieWRX** » Tue Jun 24, 2008 8:07 am

Yes...still on the topmount and will keep it that way for this year at least.

I hear the topmounts are good for between 400 - 415bhp and it's very doubtful i'll get near that on the VF35 from what i have been told. I would like to squeeze a bit more out of the turbo if poss and i was hoping 1.5-1.6bar would be OK but won't go the extra until i know it OK to do so, and i would be very happy with that.

Do you know how early the VF35 is meant to be on full boost??

duncan · Post by **duncan** » Tue Jun 24, 2008 8:15 am

The STi 8+ top mount is good and should be good for 400 but you are fighting a losing battle trying to do it that way, I tried to resist it but in the end a FMIC is always better at cooling the air.

You wont hold 1.6 to the redline whatever happens so plan on tailing the boost down as the turbo runs out of its abilty to flow enough air. The std ecu is also not very good at controlling boost at that level.

Full boost - depends on what full boost is. My VF43 made 1.5 bar at 3000 ish. The FP Green made 1.5 bar at 2800. But 1.5 bar on a bigger turbo is ultimately a lot more air shifted.

ScoobieWRX · Post by **ScoobieWRX** » Tue Jun 24, 2008 8:42 am

Fair enough. We'll see what happens with some further turbo/WGD tweaking.

I'm going to resist FMIC for now. When i do go FMIC i'll have bought an MD321H or T, bigger injectors, a proper CAI setup, another fuel pump (run twins), proper fuel rail and new PPG gearbox internals as i'll need them by then for sure. I've got a year to save up so i may as well do a proper job when the time comes!! In the meantime i need to sort out handling. It's neverbloodyending this modding lark!! :lol:

Anyway........You'll be running 700 or 800bhp by then. I look forward to seeing that

A thousand thanks for the advice Duncan....top man!! :thumb:

Gerry H · Post by **Gerry H** » Tue Jun 24, 2008 9:39 am

What's the thinking behind the MD321 Francis?

duncan · Post by **duncan** » Tue Jun 24, 2008 9:53 am

Gerry H wrote:What's the thinking behind the MD321 Francis?

yeah indeed. ?

ScoobieWRX · Post by **ScoobieWRX** » Tue Jun 24, 2008 11:20 am

On recommends from many knowledgable people to include Andy Forrest, couple of rolling road owners i know of and have spoken to directly, and a good look around many forums to read what others have to say, pro tuners included.

The MD321 is suppose to be a very reliable and strong turbo giving plenty of performance to over 500bhp if required, spools up well from 3200rpm on and delivers plenty of mid-range to top end power right to the redline. For the money it sounds very good.

I won't be changing internals yet and i've heard of and seen evidence of the standard STi8 bottom end happily dealing with 500bhp long term, and will certainly handle 400 - 430bhp bhp all day long in anger, guaranteed (that's from Paul at Zen).

Why? Have you got a comparable alternative?? Or are you thinking something different??

duncan · Post by **duncan** » Tue Jun 24, 2008 12:05 pm

there are plenty of alternatives with the same performance and lower price. the fp green and hta green being just two of them. i know paul was very impressed with the spool up on my green and said there was nothing in it between the two.

i would be cautious about believing 500 from a std block.