DIB_23

Hi guys, this is my first post on the forum

I had my car remapped this week and I must say I was slightly disappointed - not necessarily with my mapper who was a nice bloke, but the fact that I had spent time and money on upgrades in preparation.

I've got a 2.0L Blobeye Wagon with a certified prodrive performance pack which should have been 265bhp / 260 lb/ft.

I've added:
Almost new VF34 turbo
K&N panel filter
Decat up-pipe
Prodrive sports cat
Silicone inlet hose
DW200 Fuel Pump

I've also polished / removed flash and radiused all ports on the turbo, Knife-edged the throttle plate, and made various improvements to my standard intercooler and it's under tray.

It was mapped at 1.3bar coming in quite early and holding until 5500rpm on the standard boost solenoid.

Now, from my research I thought since the VF34 will flow more air than the outgoing standard TD04 at any given level of boost, I should be 310-325bhp, which I believed would not be too much strain on the WRX internals / 5 speed box. I always use Tesco Momentum 99 RON fuel.

After the run, it showed...265bhp (@5,500rpm)/ 287lb/ft (@3,900rpm).

Now, I realise that the car is 10 years old so probably wasn't running at 265 bhp on the PPP, and different rolling roads show read differently (mine was done on a MAHA) but the results were 50bhp lower than expected.

I did say to my mapper that it is my daily driver and I didn't want to push it too far, but I came away a bit disappointed, and wondering why.

Dont get me wrong, the car drives better - smoother and definitely more lively but how can this be since all the tuning guides and websites I've read - Andy Forrest, Race Dynamics etc say north of 300?

I know it's not about chasing numbers but I wanted to get the best performance from bolt ons.

As I said to my mapper if that is the reality with my spec, then so be it.

Any views / experiences gratefully received, backed up by reasons would be great I must have been an engineer in a past life as air flow, calculations really interest me and I like to know how things work (or why they don't).

I have contacted my mapper who has offered me my money back or another remap, but how can an extra 50bhp be achieved?

Lastly, would 1.4 or 1.5bar on the VF34 kill it and my engine?

Thanks

the shreksta

iTrader: (20)

Have you got an sti intercooler?

Who mapped it?

DIB_23

no- standard intercooler which I've heat wrapped/shielded, knife edged the elbows, deflector plate in undertray and more under the intercooler to improve exit flow / deflect heat from the turbo. I've also tilted the i/c to 20 degrees and re routed various wires and pipes under the intercooler for less restricted exit air flow.

Interestingly on the intake temperature graph, IAT actually reduced all the way to 6,000rpm

*matthewturb2000*

iTrader: (11)

I'd take the money back and go somewhere else for mapping

Tidgy

got any graphs from it?

sivo

iTrader: (30)

Don't rule out your PPP downpipe causing a restriction.
My sti made 303 with the PPP downpipe and 342 with a 3" decat.
That's with a vf43 turbo.

Siv

DIB_23

still there's only one cat in the system now and there's not much material in the prodrive cat to cause that much of a restriction surely?

Tidgy

heres the graphs from my old uk turbo on a vf34

Tidgy

cats get clogged over time and will never be as free flowing as a full decat.

did you get some graphs printed off the dyno like the ones i just posted?

sivo

iTrader: (30)

That's what I thought but they do break down with age.
My PPP downpipe cost me 40bhp...... Simples !

Siv

Tidgy

might not be the case. Some cars just dont do the power no mater what.

Did you get the graphs?

DIB_23

Yeah - i'll post once i figure out how to attach a photo of it...

Wheel power shows 181bhp

Tidgy

haha, you got a photobucket account?

DIB_23

Not a great pic, sorry.

Tidgy

um, can you get it a bit more in focus?

Uncle Creepy

Who mapped it?

DIB_23

Nah, too much caffeine today, cant keep a steady hand! Will try and scan it tomorrow

DIB_23

Mapped by sheffield rolling road. Nice guy.

Tidgy

WIthout being able to read the text can't really tell whats what.

DIB_23

Lines from top to bottom - torque, engine hp, wheel hp, drag which i believe is the transmission loss.

Tidgy

so no mention of AFR or boost?

jayallen

iTrader: (31)

What did the mapper say about it, surely he must of been equally puzzled by the result?

bludgod

iTrader: (3)

I don't see any mention of injectors on your list of mods - standard injectors will be maxed out by the td04 so you will be heavily constrained by them on the larger turbo.

The vf flows more air at higher rpm but your td04 will come on stronger and sooner. Without sti injectors your map would be fuel limited in the top end and this would be consistent with your higher torque but similar top end figures in my opinion.

DIB_23

Mapped on standard injectors, but I took along some hawkeye injectors to put in but he reckoned they wouldnt be needed and would make the car less driveable lower down the rev range

Tidgy

nah, thats way down on what they are capable matey (the 260 figure). Mine above (340) was on standard v5 uk injectors and just an uprated fuel pump as far as fuel system goes. Mine were very close to maxed but as you can see did the numbers

Tidgy

The injectors from a hawk arn't that much bigger

ditchmyster

iTrader: (7)

You need a different mapper, sounds to me like he's clueless, about Subarus at least, you need to take it to Pat at Scoobyclinic.

This is the perfect example why not to use people that don't live and breath Subaru or have the resources on site to solve problems there and then.

265bhp from a VF34 is a joke, even with standard injectors and top mount you should see close to 300 before the injectors max out and the top mount will still do somewhere in the region of 330bhp.

You need to change the Injectors, if you do the top mount and full-decat you should see in the region of 340/350bhp.

Take the money back option.

Tidgy

nah, injectors will have plenty even without a fpr.

But if you have them then def switch em out

bludgod

iTrader: (3)

they are enough bigger though, going from 440 to 550 is a lot of extra headroom.

I agree the numbers are low though even with the measly injectors, but I wouldn't say it's fair to compare the performance of the V5 injectors to the later WRX ones.

If we got a clearer scan of the dyno sheet the AFR might help explain.

Tidgy

no no, you missed what i was getting at.

Bigger injectors take longer to flow fuel, hence why they arn't great low down. What i ment was 550's arn't a big enough jump to make that an issue

Aka was the OP is being told about not using them is rubbish