andythejock01wrx

G'day Scoobynetters,

Well, this is a tad premature, it'll be a while before I change cars. But I fancy a Hawkeye STi when I do, so it's still fun to dream about what I'm gonna to to the thing when I get the funds together !

So, do you guys have any ideas as to the likely bhp on the 2.5 with the following mods ?1) Std VF35, but with decat and remap

2) TD05 18G (would injectors be required ?)

3) TD05 20G (are they laggy on the 2.5 ?)

4) MD321H

I know, I know, you'll all say the MD321T is the one to go for, but I'd rather avoid expensive internal mods.

Any thoughts greatly appreciated.

AndytJ

renno rannes

20g I reckon, considering standard internals.

shadower

mine run sweet on andy f td06 370bhp on std internals

dynamix

iTrader: (3)

std Turbo is the VF43 not VF35

With supporting mods on that turbo you are around 380bhp & 410 lb/ft

I wouldnt want to go much more than that on std internals power wise and the std turbo will get you there.

andythejock01wrx

Cheers Dynamix. That suggests you get 100bhp more from a decat, remap and fuel pump - is that right ? What's the difference between the VF35 and the VF43 in terms of spool and power ? Is the VF43 simply an evolution of the VF35 ?

dynamix

iTrader: (3)

The VF43 has a bigger exhaust housing (P18) vs the small one on the VF35 so has higher potential. It is slightly slower spooling but you would not notice that really as when mapped you can get 1.4 bar at 3000 rpm and ride the wave of torque from the 2.5 litre. No need to thrash them as a result.

A possible limit will be injector duty cycle with the std injectors but that varies by mapper from what I have seen and the intended use of the car.

A good 3 inch turbo back exhaust really sets if free but it has to be remapped for it or else it just boooooosts and may well cost you an engine.

andythejock01wrx

Thanks again Dynamix. Looked at your profile (your Scoob looks great btw ) - I note yours is pushing out 360/400, but you say above that 380/410 is available on the std turbo ?

shadower

when paul at zen mapped mine on the std turbo 350 was max for vf43
full 3" decat pump and pannel filter
then swapped turbo for more

Jolly Green Monster

iTrader: (4)

20g

dynamix

iTrader: (3)

My profile is not up to date

andythejock01wrx

Afternoon Simon.

Is the 20G noticeably laggier than the Vf43 when used on the 2.5 engine ? What bhp would you expect from it ? Would different injectors be required ?
Finally, what bhp would you expect (it would have to be a fair bit better than the mapped Vf43 to be worth doing).

Cheers,

Andy

andythejock01wrx

LOL.

Jolly Green Monster

iTrader: (4)

not much laggier no.. 360~380 etc.. never like quoting figures.. did a P1 with 2.5 and 20g last month.. felt like 360 as ran out of fuelling so couldn't run as much boost as we wanted.. it put his mates 400bhp evo to shame apparently.

it's how it goes rather than the numbers

the standard injectors will max out.. better to go with 650s.

Simon

ps. as you in scotland I assume Andy does your mapping so speak bwith him

dynamix

iTrader: (3)

yeah, I am now running 800 + cc injectors, APS CAI, various other external (to the engine) mods and with recent mapping work I have been able to push to around 323 / 345 at the wheels according to delta dash. It depends on what losses you work out at to get to the flywheel figures but it is comfortably quicker than before when it was 360/400 as shown by reduced in gear acceleration times.

But, this is as far as I would take the std internals - the std uk pistons have their limits and I am pretty much there particularly with my track work.

The std VF43 is at the end of its comfort zone at this level so a more efficient turbo such as the 20G/321H/T/FP Green would help but the temptation would be there to push it further and this could lead to an expensive rebuild... and you would be tempted, curiosity gets the better of you

Personally, the next step for me is a fully forged engine that would be able to cope with whatever turbo I want to strap to it. This will be an FP Green.

andythejock01wrx

Thanks Simon.

andythejock01wrx

Sounds pricey, but a whole lot of fun !

Was thinking about doing a track day in my 300bhp 01 WRX in the next few months. I'm aware of the tyre and brake pad costs, but how common are costly mechanical problems on tracked Scoobs ? (Remembering it's a 6 yr old 75,000 ml car)

dynamix

iTrader: (3)

Yes - pricey, but will be worth it in lots of these

There should be no reason why it would fail with a little preparation/thought.

Make sure oil is good and check it through the day - they can lose some (or a lot) on track and running low is the only reason I have seen any scoobies fail on track.

Tyres - it depends on what tyres you run as to what kind fo wear but generally pump the pressures up a bit on tyres such as Toyo T1-R or Goodyears to stop the tyres folding under and wearing excessively.

Brakes - give the car a chance to cool down between sessions (with the handbrake off) and it will be fine but good pads, braided hoses and most importanly good brake fluid will do the perfect job.

Butty

iTrader: (2)

Here's the wheel power increase of a simple VF43 remap/3" exhaust combination:




The blue line is a std 06 STi, the red is a Zen remap with my spec (see my plus profile)
The low down torque increase is a massive 100 ftbt!
More to come as the adv multiplier was pulled back to 0.69 due to creep causing some problems in this cold weather.

The Vf43 on a 2.5 engine is very capable - if you are looking for even more output then bottom end work is on the cards. I'd really recommend trying the std turbo first before going any further.

nick

dynamix

iTrader: (3)

andythejock01wrx

Thanks Dynamix.

I have Toyo T1Rs (getting near the wear indicators), braided hoses, Dot 5.1 Fluid and pagid pads. Figured a track day might kill the pads and finish off the tyres (which i need to replace soon enough any way).

I'll bring some extra Silkolene Pros S 5w/40 in case of top ups !

andythejock01wrx

Cheers butty.

What figures are you on at the mo ?

And what difference does the 3 port solenoid make ? Does it allow the mapper to obtain more boost ?

Butty

iTrader: (2)

If a factor of 1.23 is applied to the graphs then I recon that its 345/370.
Some more to come once creep is tackled and I can resolve the timing being pulled back.
I'd be happy to get to Duncs figures of 360/400.

I can't quantify the addition of the 3 port other than it is hopefully allowing a quicker boost control. Unfortunately boost control is being lost in 5th & 6th gear at the moment and I'm hitting just over 1.5 bar (unintentionally).

nick

dynamix

iTrader: (3)

The 3 port makes for better boost control.

I didnt notice any difference in spool up but then it is very difficult to quantify that when it spools like a ninja anyway.

The benefit that I found was much better control of boost levels through the range and more boost up top. More boost isnt already the be all and end all though.

I did a write up on it but these are the main points:

Runs done in 3rd gear, all on the same piece of road.



Yellow line = as it was with 1/4 tank of Tesco 99 (14C ambient)
Blue & Red lines = position now with the Prodrive Boost Control Solenoid (9C ambient)

No difference on spool up but it definitely holds boost better and as such the gains in bhp are pretty huge

nb: these are wheel figures

Andy.F

1620 KG ? Thats one fat Sti you have

Its a bit odd the way the power is dropping away so quickly after 5000 rpm ?

dynamix

iTrader: (3)

thank you

You keep mentioning the weight thing Andy ... you must be in a funny mood today, all that shuanee baiting

As I mentioned on 22b, the figures are not necessarily of extreme importance to me on there as I feel they are a little flattering but the shape of the curve is. All dyno runs were done with as many variables as possible constant, even down to wind speed The only main difference was the ambient temp hence why I noted it.

The power starts dipping from 5500 because that is when the boost is starting to taper downwards. (I had also been a little conservative on timing at the top end I feel) I wish I could hold 1.5 bar to redline, but the VF43 would be a flamethrower if I tried to do this and the engine would not last long. These dynos were done on pure Tesco 99 so with methanol I would feel more comfortable about pushing the envelope on the boost profile.

Can you post up a road dyno run of a UK 2.5 STi with std internals and VF43 to compare?

Andy.F

I only mention the 'weight thing' as it has a direct influence on the power numbers you produce in deltadash.
It would be unfair to compare your graph with the graph posted earlier by butty for example.
Just incase anyone was unaware.

dynamix

iTrader: (3)

True - but the weight and the contents/fuel level of the car was constant across both tests so can be ruled out of a comparison although figures as I said are not verified on a 'true' dyno.

Agree on comparing it with Butty's as I know that Butty's used a different gear - not 100% on the weight though.

Butty

iTrader: (2)

Andy, We are comparable as mine is an 06 Spec D hawkeye STi. I also used 1600 Kg as the weight.
I've been using 4th gear on all my runs.
Nick

Andy.F

OK we are possibly going a bit OT here but ignoring peak figures and looking at relative changes, I don't see how just a 3 port made that difference.

Could you not achieve a steady target boost on the 2 port ? I find that most of them only need IRO 45-60% duty over 5000 rpm so achieve target boost comfortably.
If you don't optimise the control parameters its very easy on a 2 or a 3 port, to make too much boost and lose power at higher rpm.

andythejock01wrx

Andy, can you tell me the difference in the typical bhp and spool up between the VF43 and one of your 20g's, when used on an 06 STi ?