350bhp but more importantly 300 + lbs/ft

Matt

 

oh its a goodun alright . if anyone intrested check out the for sale section,

 

vf34 will fo 350bhp with the right supporting mods so wouldn't worry about it not being big enough, vf35 is similar but not roller bearing

 

Are any of the turbos discussed so far twin scroll? What exactly does that mean?

Cheers so far by the way!!

I might yet be persuaded to a VF34. - Which car does the VF34 come in to start with?

Matt

 

As Tidgy says, you have more chances of getting 350 out of a VF34 than a VF35, but the 35 spools better, owing to the smaller exhaust housing (p15 vs 18 IIRC)

Both turbos will give you comfortably over 300ft lbs torque though.

Ns04

 

Some one correct me if im wrong about this

Twin scroll has a twin fan system, so you have two smaller fans instead of one, making it quicker to spool.

dont think vf34 is standard on any impreza is it?

 

Ah no prob, I was assuming it was a JDM STi one, or whatever!!

Matt

 

no think its a purely aftermarket one, was designed for group N rally cars iirc

 

I guess that explains its rarity over TD Hybrids then.

Wish I knew more about this sort of thing and especially fitting myself!!

Matt

 

lol, i shall expect to hear some swearing form here then lol

yeah pretty much, also the VF's arn't modable like the TD's, once there bust there bust pretty much as well

 

Ah nice.

So does the VF34 allow me to get to what I want to (power wise) without having to squeeze every little bit out of everything else?

IE as I mentioned before I know about Fuel and Injector mods being a must, but otherwise I was hoping for meat and veg exhaust, manifold, cat type mods...

I dont wanna have to lengthen the 3rd piston or like, port the head, or ummm, do some other stuff I dont understand just to get to the magic figure...

Matt

 

should be up around that figure, but bear in mind the exact figure varys from car to car

 

Car will be mapped for drive not figure anyway.

IE It can be 335bhp as long as it pulls properly out a corner where a 360bhp car might lag or whatever.

Matt

 

Go for a VF 35 then

Best spool characteristics for a turbo at this power level.

Cheaper than the 34 too!

Ns04

 

Whats my current TD04 capable of?

Matt

 

300 absolute max at a push

 

280 More common, and it'll be spent by 5.5k at which point the mappers have to pull the boost back to stop the poor little thing going nuclear!

Bigger turbos pull to the redline!

 

yeah sorry should have said, thats giving it death mapping and if your lucky.

as our man said 280 is more common.

for what your aiming for its gonna need to go

 

Thats fine. The TD04 already feels dead at maybe, 6000 RPM and no amount of spanking changes that.

I think its because of this that I feel so dissapointed in the Impreza, after my Focus ST (which had a Wolf uprated turbo) it seems to spool later, with less kick and pulls less hard, for less time. And i'm not talking a little bit, im talking worlds of difference.

The figures I am quoting are the same sort as the Focus had, but I suspect unlike the Focus the Impreza will be able to put the power down properly!

Matt

 

Personally I don't find the lag so much of a problem (of course there's more than the td04, but it's not that noticeable if you're above about 3800 RPM), it's more the late spooling that is annoying IMO. E.g. if you're pulling away from standstill, it's either gotta be a hard launch at 5000 revs, or a normal 2000 rpm pullaway with foot planted to floor and wait-wait-wait until the revs climb past 3500 With the TD04, it came on boost a lot earlier in the normal pullaway situation.

Also, because of the late spool, you have to plan your driving a lot more, as any rapid acceleration will likely require a down shift to get the revs up. I'm not the best driver in the world, so i sometimes forget to shift down enough when entering corners and stuff, and my incompetence was somewhat masked by the td04.

However, keep the engine on the boil, and it flies (From 3700 rpm onwards i have more than 200bhp available, so maybe it just feels so sluggish at lower revs because there's a lot more power available higher up)

 

Also, i'm not sure how much torque a normal wrx produces, but mine passes 200lbft at 2850 revs on my graph

 

Good post Henrik.

I dont think I am an amazing driver either and I have found the TD04 to be wanting due to my driving... but its getting better!

Matt

 

with td04 mine hits 200bhp @ 3.8k, with vf34 it hts 200bhp at 3.9k, but the difference in performance low down is huge

mine now hits peak boost at 3750rpm roughly 1.25 bar iirc

 

Hmm, that would indicate that my td05-20g outspools a vf34 and a td04 (I'm jesting)

My graph is from a deltadash (on the road), so may be different on a roller (see attachment - bob rawle mapped it)

 

you got the boost grpah nocking around?

also bear in mind delta dash tends to read a bit high

 

nope, no boost graph at all... I need to take it onto some rollers at some point

 

would a TD05 16/18g spool quicker than the 20 I guess? And still allow for more power than the VF34?

Good discussion this, thanks again!

Matt

 

ahh righto, be interesting to see the comparison, hurry up and sort it man pmsl

 

the 16, 18, 20 are in size order so guess the lag increases in line with max output, 340, 370 and 400 respectivly

 

In that case the 16 still seems like a good option to me, or the VF34 which appears to be comparable.

Cheers!

Matt