nickyrhodes

Hi,

After all the nice advice i've had so far i'm starting to think if im going to get a power fc and mapping that i probably should put a bigger turbo on. Mainly cos my mate has a little Seat with 285hp that wastes me lol.

So, what i want to know and start looking at is what is the best turbo to go for (given that im not clued up on the differences between TD and VF etc)?

Mods so far on my MY98 uk classic:

Full Decat, Panel filter, Strut braces, Brembos, 18" wheels

Everything else is standard, so what will the stock car take without replacing clutches and gearboxes etc? too me if im gonna for out 750 for a mapping i might aswell upgrade the turbo and save myself another mapping afterwards.

Cheers guys
Nicky

Gear Head

iTrader: (2)

Right, this is the spec that has been used by many others on here and has worked wonders.

VF23/24/28/30/34/35 turbo £300 (these all have differences but will basically give you the same results.

Ported Headers £100-£150
Uprated fuel pump £100
3 port boost solenoid £90
Power FC remap or Ecutek (99/00 only) £600-£800

+ what you have already should see a reliable 320-330bhp with around 300-320lb/ft of torque.

Hope this helps.
What model year Impreza do you have?

nickyrhodes

Hi,

Its a MY98 UK GC8 EJ20K.

I know i would have to upgrade the fuel pump, but would i have to go with the boost solenoid and ported headers?

Whats the difference between the VF numbers? Is it compressor size? I assume the bigger the number the more lag but more power output?

Replacement or piggy back ecu is the only option for mine with the 3 plug ecu

Gear Head

iTrader: (2)

You don't 'have' to upgrade the solenoid and headers, but the solenoid allows the mapper to have more control over boost, and the ported headers help to reduce lag.

As for the VF turbos:

IHI Turbos


VF22

This turbo has the highest output potential of all of the IHI VF series turbos and is the best choice for those who are looking for loads of top end power. The top end power however, does not come without a cost. The VF22 spools significantly slower than the rest of the IHI models due to the larger P20 exhaust housing and is much less suited for daily driving than some of the other models. Although the largest VF series turbo, the VF22 is not quite optimal for stroked engines or those who wish to run more than 20PSI of boost.

VF23

This turbo is considered a great all-around turbo. Like the VF22 it utilizes the largest P20 exhaust housing. This housing is mated with a smaller compressor housing of the of the VF24. This turbo is considered optimal in applications with range from mild to slightly wild. It does not have the same top end power of the VF22, but spools up significantly quicker.

VF24

This turbo shares its compressor housing with the VF23 however, this housing is mated with a smaller (P18) exhaust side. The smaller characteristics of this turbo allow it to provide ample bottom end power and quick spool. This turbo is very popular for Imprezas with automatic transmissions and Group N rally cars.

VF28

This turbo came standard on the STi Version 5. In terms of overall size, it is smaller than the VF22, VF30 and VF34, and about same size as the VF23.

VF29

This Turbo is nearly identical to the VF24, with the same compressor and exhaust housings. However the compressor wheel in the VF29 is has been changed slightly. The changes made to the compressor wheel in this model are generally viewed as improvements, and as such this unit is typically chosen over the VF24.

VF30

The VF30 is commonly considered the best bang for the buck turbo in the IHI VF series line. A relatively new model the VF30 features the same exhaust housing as the VF24 but a larger compressor side similar to the VF22. The combination of these two parts results in increased output potential without the lag associated with the VF22. Although it doesn't offer the top end supremacy of the VF22, the VF30 is a great compromise between these unit and the quicker spooling models.

VF34

The VF34 is nearly identical to the VF30, with the same exhaust housing and compressor. However the VF34 goes back to the ball bearing design, and in doing so achieves full boost approximately 500RPM sooner than the comparable VF30. The VF34 is the most recent IHI design and as such costs slightly more than its counterpart. Top end performance and maximum output are identical to the 30.

VF35

VF35 The VF35 has identical internals as the VF30 and it uses divided thrust bearings. However, the exhaust housing is a P15 which means this turbo will have fantastic spool characteristics. This turbo is standard on the new WRX Type RA. LIMITED SUPPLY.

VF36
Roller bearing version of the twin scroll VF37, also has a titanium turbine and shaft for even quicker spool. Same compressor housing as VF30/34, however twin scroll P25 exhaust housing provides slightly better top end output due to reduced exhaust pulse interference. This turbo is good for 400HP and used on JDM STI Spec C from 2003 onwards.

VF37 (thrust bearing)
Enter the age of twin scroll IHI turbos. Same compressor housing as VF30/34, however has a new twin scroll P25 exhaust housing that provides slightly better top end output due to reduced exhaust pulse interference. Twin scroll also provides better spool up for improved low down response over the VF30/34. This turbo is good for 400HP and used on JDM STI from 2003 onwards.

VF38
Twin scroll turbo with titanium turbine and shaft. Smaller compressor housing than VF36/VF37 provides tremendous spool up capabilities but less top end than VF36/37. The spool capabilities of this turbo are demonstrated on the JDM Legacy GT, which reaches peak torque at 2400RPM.

VF39
Single scroll turbo used on USDM STI and latest 2.5L STIs released internationally. Smaller than VF30/VF34.

VF42
Exclusive turbo to the S203/S204 models, this features a twin scroll design with a slightly larger compressor than the VF36/37 turbos and different turbine design (more blades). The VF42 is a roller-bearing turbo and is likely of similar size to the VF22 turbo, but with twin scroll exhaust housing for faster spool and superior top end performance due to reduced exhaust pulse interference.

xxQuartzxx

sorry to hijack the thread .. but i'm having the same problem .. knowing what to do etc etc .. mines a my99 classic

full decat
induction kit
megan headers
seems about right to upgrade the turbo for somthing a bit more punchy
now for the first map its about 750 quid .. but only getting the ecutek flash

i'm thinking of changing the euc for the apexi pfc and keeping the stock ecu as a spare or selling it ..

gawd its a mine field out there ..

so hopefully a few scoobynetters might read this and give us some good recomendations on what to go with ...


Quartz

Gear Head

iTrader: (2)

see above!

nickyrhodes

Hi,

thanks for the info chris. Just ordered a walbro pump as a start, saves the extra cost at time of mapping.

For anyone who is interested flat4online are selling them on ebay for 80 quid delivered including kit.

eBay.co.uk: * * Walbro 255 Fuel Pump & Kit Subaru Impreza 92-00 * * (item 250052572879 end time 01-Dec-06 20:00:00 GMT)

Next question, for me and quartz, where are good places to buy turbos from, probably recon ones. Is the VF23 a good place to start as a mix of power and spool? Aiming for around 320bhp i reckon, what about the likes of the TD05-16g etc are they any good?

Gear Head

iTrader: (2)

The 16g is a bit more laggy than the VF24 and up.

Damocell

iTrader: (1)

I'm in the process of doing a similar conversion aiming for 320 bhp been getting parts as and when cash flow will allow.

uk 99 turbo
vf35 (too fit)
power fc (too fit)
fuel pump (too fit)
3 port (too fit)
sport cat (too fit)
exhaust
STI 8 intercooler
Panel filter

Got the walbro for £50 and the 3 port for £60 all brand new from America, plus the exchange rate is nearly $2 to the pound as long as they write Gift on the customs slip you don't get charged the import duty

Got everything now just need it mapping.

ps got the power FC for £400 with commander, a Zen map is £329 (from their website) total price of £729.....thats cheaper then some Ecutek's

Damo

nickyrhodes

Hi,

Sounds good, where did you get the turbo from and for how much if you dont mind me asking?

Did spot the walbro from usa but wanted to get it fitted before it goes on the rollers in 1.5 weeks time.

Cheers

Damocell

iTrader: (1)

The fuel pump arrived 4 days after I paid for it!!!

Turbo cost me £300 and had only done 10K miles

Damo

movi-star

iTrader: (1)

Damocell, your doing almost the same as me at the same time (Ive got a MY00), I saw you get that VF35 of ebay for £303 as I was watching it!! I got VF35 of here a few days after that, I got the walbro off ebay brand new £57.

Where did you get the Apexi Power FC from? I need to choose between Nengun or from JPS Trading on ebay.

Im also going to have it mapped at Zen as I live just around the corner from there.

It will be interesting to see how you get on as you seem to be a bit further ahead than me.

timchump

Hi Damocell - i'm doing pretty much the same as you to!

uk99

sti8 intercooler and scoop
sports cat down pipe and hks exhaust (all 3 inch)
panel filter
walbro fuel pump
ported headers
lightned flywheel
3 port boost solenoid
vf34

and a ecu tek remap by bob rawle in 2 weeks time

whats the advantage of a power fc btw?

would be interesting to compare results when we've both finished?

Gear Head

iTrader: (2)

Think I might be tempted to go with a TD05 16G. Lots of being 'shoved back your seat!'

New_scooby_04

iTrader: (4)

Hi Chris,

Check out the vid by Jasonius showing the mid range of the VF 35! I think that'll do nicely sir. Be aware that I know of at last one person on here (Floyd) who went from a VF35 to a TD05 and regretted it; the 35 spools quicker and earlier as I understand it (especially relevant if you have a non-sti). Also Td05s have more of a reputation for eating gearboxes so the mapper will have to "feed" the power in progressively to stop this which might mitigate any shove in the back advantage. As it stands, VF35's are producing 330+ ft lbs of torque in conversions I've heard of, which is comparable to a TD05 16G

Ns04

Damocell

iTrader: (1)

Decided to go with the power FC as heard really good reports about it, plus it came with the commander so I could play with settings a bit. I think the part throttle response is supposed to be better as it is closed loop, but i could be really wrong here!

That video of Jasonius and the write up by ns04 on this conversion is the reason why I'm getting it done.

Video can be found here https://www.scoobynet.com/general-te...0549-vf35.html
And right up here https://www.scoobynet.com/scoobynet-...xperience.html

Ns04 I realise what you are saying about the gearbox, so before I got the turbo etc I had an STI 5 gearbox, diff and an Exedy Organic clutch fitted.

The box has already improved the acceleration in 4th and 5th so can't wait to get all the other bits on!!

Bought the power FC from a guy on here, brand new for £400, did look at the two shops that were mentioned, Nengun seems cheapest.

If other people are getting the mapping done at Zen would it be worthwhile trying to start a group buy?

Damo