wintn

I gather that the VF24 has a boost limit of 17psi (due to small turbine wheel which may overspeed?).
As the VF28 has the same turbine and compressor wheels and housings is it also limited to 17psi?
What would be the effect of demanding more boost?

Any help appreciated.

Bob Rawle

Hmm that sounds like you have been misled, both those turbos would be quite happy at 1.4/1.45 bar mid range and 1.25/1.3 at 8000 rpm.

cheers

bob

wintn

Thanks Bob, always seem to get a sensible reply from you.

Info came from the Scoobytuner.com web site:
http://www.scoobytuner.com/tuning/?tuningID=41.

See quote below:

"IHI turbo.
The VF series (VF22, VF23, VF24, VF29, VF30) are the most common direct replacement turbos. All VF-series turbochargers use the same roller bearing, water-cooled core assembly. The differences are in their wheels and housings to achieve different flows.

The VF22 has the largest potential for peak horsepower. In other words, in the IHI model range, the VF 22 supports the highes boost levels. It is capable of running up to 25 psi. Because it is a roller bearing turbo, turbo lag is minimal...the boost comes on around 3300 rpm. Expect to max out the VF22 somewhere in the 400-450 hp range.

The VF23 starts the middle ground. It comes on boost around 3100 rpm and is capable of running 20 psi of boost. Expect to max out the VF23 somewhere in the 300-350 hp range.

The VF 24 starts to come on around 2900 rpm and will significantly improve power through the midrange over the stock TD04 turbo. However, the VF 24 is only capable of running around 17 psi.

The VF23 and VF 24 are a great replacement for those who value drivability higher than maximum power."

Simastallion79

What is the max boost for standard turbo before it will blow-up.
Would like to know as I've bought apexi avc-r boost contoller

banny sti

iTrader: (68)

what is max boost you could run on a vf23 midrange and top end?

Welloilbeefhooked

iTrader: (3)

What is the max boost of a .........................

Search?

john banks

To trace the 160000 RPM curve which is the maximum the compressor plot I have is plotted to, assuming PR is 0.05 bar higher than boost, with VE at 90% at 5000 RPM and dropping 5% every 1000 RPM thereafter would suggest 1.35 bar at 5000 RPM, 1.2 bar at 6000 RPM, 1.05 bar at 7000 RPM and 0.95 bar at 8000 RPM. The values change based on the assumptions you make, and the compressor may be able to run more than 160000 RPM safely. On the other hand it may explode into lots of pieces that your intercooler may or may not filter for you before they go into your engine. Compressor plots are just a hint, your mileage may vary etc etc. Always read the label

banny sti

iTrader: (68)

i know its 20 psi but what does that eqaute to in bar? as i want my avc-r setup

john banks

14.5 PSI = 1 bar

14.2 PSI = 1 kg/cm^2 which is the units that the AVC-R uses. So it is about 1.40 on the AVC-R. I would taper it at the top. People have exploded VF23s running 20 PSI. Check detonation, AFR, EGT and that you are actually making more power across the RPM range for a given boost increase.

banny sti

iTrader: (68)

i also have the s-afc 2 which will allow adjusments to the air/fuel ratio, with headers, fmic, decat, induction, uprated fuel pump and a boost increase what sort of power could i expect from the vf23?

john banks

About 100 BHP over a standard UK car on the same dyno.

StickyMicky

i ran my vf 23 at about 1.44bar midrange or sumthing stupid and it lasted 1 day

it has been rebuilt with a new cart from a vf28 i got for free, i never even had it balanced or anything, i just cobbled it all together and limited the boost to about 1.37bar peak and its been fine for a good few thousand miles now, no noise, no problems, no blowing to a million peices

banny sti

iTrader: (68)

i have a goal of 350bhp/330 torque, would a vf34 be up to the job?

john banks

If you just want those figures on a safe tune without octane booster better choose your dyno carefully.

Bob Rawle

The VF23 can be run at similar boost BUT, its somewhat like a VF22 in type and those have a habit of exploding compressor wheels so 1.35/1.4 bar mid 1.2 to the red line is fine on that, mapped many like it with no issue, decent power and torque to be had, used to be the "turbo of choice" for the Eurospec car b4 the TD hybrids came along and still worth considering.

John theory is great BUT the associated mods, spool rate etc etc etc all influence (which I know you know iyswim) and you really need to set it up to suit car and mods at the time... said for the benefit of those that don't know.

bob

Bob Rawle

Bannysti ... yes with the right associated mods but you would be running with Optimax and some booster for safety. AS JB mentions without you would be pushing it a bit.

bob

banny sti

iTrader: (68)

thanks bob, the car i run is an sti version 3 so using octane booster is not a problem. its actually become a habit now. if i wanted to achieve those figures without octane booster which turbo would be best? ideally one that does not have too much lag.

john banks

You are looking for something a bit bigger than the VF34 or TD05H-16G to get 350 BHP easily on Optimax on any dyno.

TD05H-18G might be a nice one for 350 BHP, but not a huge amount of data is known about the 18G. 20G would manage and keep the power band reasonable given that you have an STi rev limit and power band.

madou

John

There are some 18G threads on Nasioc.com such as

http://forums.nasioc.com/forums/show...light=18g+vf30

and also

http://www.wrxforum.com/cgi-bin/ulti...c;f=3;t=005692

"Please allow me to conribute a little bit. I have run a VF22, 50trim then a TD05H-18G turbo my 02 WRX. The 18G was by far and away the best turbo for power and spool. It spooled slightly faster than my VF22 did and WAY out performed it.

Just as an FYI if you do a search over on clubwrx.net for username "Tronner" and 18G you will see that he dynoed at 28x whp and like 27x wtq on 90 octane at 17.5psi on the 18G turbo at 4000ft above sea level (SLC) on Cobbs dyno with Trey tuning it. When I dynoed my car on Cobb's dyno 1 year previous to that AT SEA LEVEL (Plano TX) running 17psi on my VF22 setup I only made 265whp and 235wtq. "

New Deadbolt site has the usual "18G made by squeezing 20G" compressor map, but does offer commentary on the various compressor / turbine combinations

http://www.boostplanet.com/

john banks

Trouble with US dyno figures is comparing them with ours. Apparently reading NASIOC you can have 350 WHP out of a VF22. I get about that out of a turbo two or three sizes bigger

banny sti

iTrader: (68)

how much for an td05h-18g? and where can i buy one from?

alanbell

iTrader: (6)

andy f , do a search on here ,

madou

following the links above ...

http://www.boostplanet.com/product5.htm

http://www.boostplanet.com/united_kingdom.htm

madou

Agreed, posted out of interest in relative, rather than absolute numbers

Jay m A

iTrader: (2)

PMSL at "United Kingdom and Scotland"

madou

Andy F. probably insisted that Jerry used that wording

banny sti

iTrader: (68)

the credit card is in trouble

StickyMicky

small note which i had forgot about

i belive scooby-si is running about 340bhp and 370lbft from his vf23

john banks

If he is running a bigger engine it will produce the torque at lower boost and be less likely at least in the midrange to overspeed the turbo.

Andy.F

lol, Scotland, that little island to the North of the UK