wintn

Just fitted a VF24 to my MY99 and am disappointed with the spool-up time.

Perhaps I should explain:
In 4/5th gears steady-state boost is 1.0bar (15psi) at 3000 and 1.15 (limited by MBC) at 3100, so actual achieved boost/rpm is OK.
However, lets say I am cruising at 3000 in 5th and plant the throttle. Boost takes a whole 2.2/2.3 seconds to build up to 1.0bar, and if this doesn't sound very long it feels like an age waiting to overtake! (can't change down with wife on board).
Same thing in 2nd, it takes 1.6/1.7 seconds by which time the revs have built up to 4000.

Does this sound normal? Performance once the boost is up is fine and it flies from 4000 to 7000 (40-60 in 2nd 1.9s, 50-90 in 3rd 5.7s, 30-70 in 2nd/3rd 4.8s).

One point, the turbo was a used refurbished (allegedly - obviously dismanttled & cleaned) unit but it makes quite a loud mechanical wine when spooling up, and can be heard spooling down when the engine is turned off. I wonder if this is a bearing (thrust side?) which is causing excessive friction?

Other mods are full decat but with original rear box, panel filter, Tec 2.5 and MBC set just below fuel cutoff - about 1.15bar (16-17 psi).

And, no, I have not had it remapped with the VF24, would this make a big difference?

bighead

iTrader: (1)

a remap should make a difference .......but don't really know how much of one though

megrac

If you used the oil feed banjo bolts that came from the td04 they could be giving the vf29 too much oil.

Bob Rawle

Correct, you need to fit the oil feed banjo (cylinder head end) from a JDM spec car to restrict oil flow, otherwise it will be over pressured. Any VF turbo needs this. bear in m ind that compared to a TD04 the VF24 will be relatively laggy, the noise is a concern, bearing whine normally indicates a limited life.

bob

wintn

Thanks for the responses guys.

I did wonder about the oil feeds, put a query in the forum but no response so fitted the TD04 one (theory - bigger hole, more oil may be safer but IO guess it may damage the seals?).
Now fitted the original VF24 banjo with smaller hole. Guess what, spool-up appears to be a bit quicker (0.2/0.3s improvement). Don't know why it should be, may be me taking measurements with a stop-watch in traffic (bit iffy!).

Can anyone give a guide to how to assess, and compare, spool-up?

Thanks Bob, yes, I guessed the whine could indicate a bearing on the way out, sounds like the thrust side. I will stick with it for a while to give the turbo a good road test and then refit the TD04 until I can sort something out. Anyone got a good FV turbo centre cassette, maybe a turbo with damaged wheel?

andypugh2000

I thought the VF series turbo's did whine slightly anyway at low rpm??

AvalancheS8

The friction and spool up advantages of ball / roller bearings are negated if they are getting too much oil, pushing the ***** or rollers through all the oil creates friction. They only need to be oily, not full of oil.

Plain bearings as in the TD04 need more oil as they are relying on the oil to keep the spindle floating on a pressurised oil film.

wintn

Since this thread started I have fitted a high flow fuel pump (Henko 255 l/h) and this has greatly improved power, response and spool-up time. Was weak before, amber on afr and fair bit of knocklink activity. This has cleared with hardly any knocklink and consisten blue/green on afr.
Mind you fueo consumption has increased (again). Looks like remap time.

Scott.T

iTrader: (2)

I've got a VF28 to fit next week in place of a TD04 (MY00). Have you got any photo's of the Banjo's.
I understand the principle, but can't for the life of me think what your talking about.

Glad I spotted this thread though or I would of been gutted with the spool up.

craig5

the banjo bolt you need is the one at 12 o clock near the front of the turbo

andypugh2000

I have written up a little piece on surrey scoobies about swapping the turbo, it may help as there are a few things to watch out for

http://www.surreyscoobies.co.uk/modu...iewtopic&t=498

mikey-p

iTrader: (1)

So is this the banjo bolt on the turbo itself or the one on the cylinder head / block ??
Have recently fitted a Vf 28 to replace a td04 .

Scott.T

iTrader: (2)

I thought it was the block end too....

Granby

iTrader: (5)

I asked Roger Clarke Motorsport about this and they told me it was the banjo bolt on the turbo

Scott.T

iTrader: (2)

According to the Subaru Parts database the only bolt that is different is the one on the front top centre position on the turbo. All the other Banjo Bolts (I think there are 2) are the same.

Part Number for the Top one is 15194AA110, although I don't think this is the one for the roller bearing VF Turbo's
Part Number for the others is 15194AA100

Just found the P1 on the Database, which uses a VF28 and altough it lists the Turbo as being a different Part Number to the GT/UK Turbo, the bolt that we want comes back with 'no applicable part'. GREAT.......