What is hi-flowing?

[-GT-]

Good to see the next big step in turbo technology starting to filter to 'mainstream' (i know) road cars. It's a start at least, might even cause a bit of a revival for mid range turbo sports cars; the increased flexibility and response range might mean more makers consider them a viable option compared to variable valve timing etc.

Then porsche will be making cars with VTG and variocam... /drools/

The greater the range of technologies being utilised in the market the better, i say.

[Smokey228]

i was under the impression that wen u hi flow a turbo, u bore out the inlet on the turbo. allowing more flow... is that wrong?

[mic*]

Oldcorollas: on point 2 re larger turbine, it also reduces exhaust gas back pressure which is a very good thing for a turbo engine. Lets it breath better in the top end. Increasing the Radius (R) of the turbine which idecrease A/R (ie. 5/8=.625, 5/9=.55)and therefore make the boost threshold lower than before.

I was thinking of doing the opposite. Keeping the same turbine but using a smaller housing.

Isnt the area of your scroll gonna go up with the radius if you use the same turbine?

EDIT: i thought increased top end flow and a low A/R were kinda contradictory...

[Norbie]

is that wrong?

Yes, it is.

See above for the correct answer.

[mic*]

i was under the impression that wen u hi flow a turbo, u bore out the inlet on the turbo. allowing more flow... is that wrong?

No. Its exactly as it says. Increasing flow. Not suction power

You clip the exhaust turbine or put a bigger scroll over the same one. And it flows better...

As Old Corollas said, a cheap way to give you some power - at bottom end expense.

[oldcorollas]

Good to see the next big step in turbo technology starting to filter to 'mainstream' (i know) road cars. It's a start at least, might even cause a bit of a revival for mid range turbo sports cars; the increased flexibility and response range might mean more makers consider them a viable option compared to variable valve timing etc.

Then porsche will be making cars with VTG and variocam... /drools/

The greater the range of technologies being utilised in the market the better, i say.

i was under the impression that one of the main reasons VATN had not come into cars was a) low power rating.. they are usualyl small buggers, and b) with petrol they tend to coke up and sieze, whereas with diesel, since diesel is often lean (ie heaps of air but not much fuel) they don't coke up as quickly (and are more likely to be used to get the car moving, so the vanes get activated)
or so i thought....

[Smokey228]

i get ya. my mates got one on his vl, and was telling me how it 'worked' which is now clear to me, is completly not how it works

so, running a HiFlo turbo, as oldcorollas says in number 3, would be a cheap way to do it, but most suited to turbos with internal waste gates as it kills the reason of having a larger waste gate, thus not having to upgrade turbos, atleast no immediately...??

[mic*]

What is WATN an anagram for?

[chris davey]

Isnt the area of your scroll gonna go up with the radius if you use the same turbine?

EDIT: i thought increased top end flow and a low A/R were kinda contradictory...

Yep I forgot that part of the equation when I typed that out and remembered on my way home yesterday. So the effect of the increased turbine would cancel out the effect of the lower a/r. How much though is anybody's guess?

However, the effect can be worked out when only changing housing like I am thinking of.

[mic*]

You have me confused. This is what i have learnt.

A/R = X-sectional area of scroll/radius from centre of scroll to turbine shaft.

It is just an equation that indicates the shape of the housing and doesnt have anything to do with the turbine.

If you put on a bigger housing, you dont necesarily change the A/R coz the area will generally increase as you increase the radius from the shaft. Simmilarily if the area beyond the edge of the turbine is increased by (A) the radius that the centre of this area is from the turbine shaft will also increase.

It depends on how you change the shape mostly that will result in a different proportional changes of A to R and thus different ratios.

[ATMO_BT1]

i was under the impression that wen u hi flow a turbo, u bore out the inlet on the turbo. allowing more flow... is that wrong?

yes you bore out the compressor housing but so you can fit a larger compressor wheel (often as big as say a T4 inside a t3 turbo). Having a bored out inlet is often a good way to tell if a turbo has really been high flowed or not though