VOSchip vs standard dyno run

[TimRS]

I put a VOSchip in my RS and was interested to do a comparison of standard tune vs. VOSchip tune.... and with a few VOSchipped RS' getting around - I thought I'd stick the results up.

Apart from the chip car is stock, minus intake resonator. Prior to dyno measurement, my main observation was the improved top end/increase in boost. With the chip the max boost hits 15psi. This can be seen in the graph from 3500rpm onwards where the extra boost is developed. I believe 16psi is the target, which is probably being restricted by the exhaust.

Doing back to back runs, the factory tune made 106kW ATW, the VOSchip made 127.9kW ATW - a 20% increase. A bit more would be gained with anything other than the factory exhaust

Another thing to watch was the AFR's... especially doing the odd track day :P At max load the factory tune was a very conservative 10.5, the VOSchip was around 11.25, so the mixtures are good. 8)

http://imagehost.biz/ims/pictes/8873.jpg

[troopa]

Nice comparison graph.. definately high up there in the bang for buck category.

[rony]

One of the better comparison graphs i've seen, the start of the 2 different runs line up at least! BUT... its still not a very good comparison. Run the the stock ECU at 15-16psi and then we can see whats really going on.
The curve upto 3500rpm is also pretty much identical in each run, i'm assuming this is the turbo lag and the way the boost is controlled by the ECU, be nice to see more improvment in the bottom end.

[AWD_1993]

thanks for the useful information Tim! ...

I'm still waiting for my Fatsport chip, which I believe has very similar characteristics to the VOSChip ... I'd be happy with that kind of improvement ... :)

[TimRS]

One of the better comparison graphs i've seen, the start of the 2 different runs line up at least! BUT... its still not a very good comparison. Run the the stock ECU at 15-16psi and then we can see whats really going on.

Yeah i guess that would show the extent of improvements due to timing and mixtures... but I never boosted the standard tune. Though below 3000rpm there is a marginal improvement a few kW ATW, but nothing noticable on the road. The main thing was to illustrate the difference between the two tunes, all other factors remaining constant.


The curve upto 3500rpm is also pretty much identical in each run, i'm assuming this is the turbo lag and the way the boost is controlled by the ECU, be nice to see more improvment in the bottom end.

I wouldn't mind a bit more grunt down low, but I guess that's determined by the vf12. Driving the Forester GT is almost the opposite - great down low, but lacking up top. I guess a twin scroll would be the way to go - much less lag and a decent top end.

None the less I'm quite happy with the way it goes. At Winton a bugeyed STI drive asked me WTF I had under the bonnet :?: after he couldn't gain on me down the straight :cry:

[adrianvos]

The stock ECU is not that bad until boost comes on. It only dumps the fuel in when it gets on boost. There is not that much to be gained in outright power at lower rpm, but the dyno chart does not show the change in throttle response. The stock ECU makes reasonable power with the throttle nailed open at lower rpm, but it is very doughy on the throttle, and will stay in closed loop mode for a few seconds after you open the throttle. I am sure many people who use my chip would clarify that the car is much nicer to drive with the chip despite the fact that outright power at lower rpm is much the same... due to the better throttle response and subsequent improved turbo spooling.

A good exhaust will also widen the gap between the stock and chipped. THe stock ECU will just dump in more fuel, and struggles to cope with boost coming on earlier.... the chip will respond much better.

Dyno curves are great, but driving the car before and after is a much better comparison. The car feels lighter and more responsive.

Anyway, that is my very biased opinion since I make these, but just thought I would explain some of what has been said.

-- Adrian

[shaheenis]

TimRS, It is about time someone did this and posted the comparison. Good work man ;-). I now want to see your next graph with 3" exhaust. BTW are you running a VF12?

[TimRS]

Well if someone gives me a 3 inch exhaust, I'd be happy to :D It's on the todo list after suspension and fuel pump.

BTW, I'm running the orignal VF12

I've had the chip in the car for almost 12 months/25000 kms - it's never missed a beat and I have been very happy with it.

[markmcrs]

TimRS, It is about time someone did this and posted the comparison. Good work man ;-). I now want to see your next graph with 3" exhaust. BTW are you running a VF12?

Um........
It's been done not once, but twice before;
Sa dyno day (http://www.rslibertyclub.org/forums/viewtopic.php?t=2221)
With this being the dyno graph of before and after;
Dyno sheet (http://au.msnusers.com/clutchphotos/shoebox.msnw?action=ShowPhoto&PhotoID=11)

Second time;
SA dyno day take 2 (http://www.rslibertyclub.org/forums/viewtopic.php?t=7768)
No dyno sheet scanned that time.
But Hendo's car went from 116kw's to 143kw's and he has a 3' turbo back exhaust.

Mark.

[Az]

awesome bang for bucks... hail the voschip!
nowhere else can 25%power increase be had for less than $1000
(chip and zorst)

[cray-]

excellent...i had been meaning to ask this question. whether its worth getting a voschip even though i dont have a 3" zorst yet. now my question has been answered and i think some arangements will ahve to be made soon. thanks

maybe if i do the chip it'll make me get off my ass and install that walbro thats been sitting under my bed for six months...

cray-

[SubbyRS]

whether its worth getting a voschip even though i dont have a 3" zorst yet
most definitely! I'm still running the stock exhaust and the difference between non-VOS & VOS was BIG!!

[subarursliberty]

One thing I noticed with the VOS on the standard dump pipe but with cat back 3in it would ping sometimes. But in saying that I didn't have the new fuel pump install until a week after I got the dump pipe made and installed. So for what ever it is worth put your fuel pumps in asap then your exhausts. Other than that its a great upgrade.

Also another thing I have noticed was the TPS. I had complete import throttle body and TPS on my car and when I changed back the the gen RS throttle and TPS I am now getting another 50ks out of a tank of juice. I have to wonder if the jap TPS was adjusted to the jap computer (that I never had installed) making it use fuel very badly.

Other than that its the best thing I have done to my car by far. Newcastle is about to get an AWD dyno (about f'n time for the AWD rooming the streets) and I will see what it is putting down.

[adrianvos]

It is important with the chip... if you are running an exhaust with 16psi.... make sure your fuel pump is good!!!!!!

The stock fuel pump when new and operating at its full specification is good enough, but it looses flow as it ages, and it will not be good enough if it has 150,000kms on it.

I generally recommend that a replacment aftermarket fuel pump is a very good idea... the Walbros are cheap and easy to fit.

-- Adrian

[TimRS]

On the subject of Walbro fuel pumps, should i get the 400hp (2.9L/min) or 500hp (3.5L/min)? i.e. is the 500hp overkill?

[TimRS]

^^^^ :roll:

Actually, I've asked that before.

I think Adrian told me the 400hp is up to whatever the standard injectors can flow... it's probably about time I got one!

[adrianvos]

400hp is fine for stock injectors at stock pressure.

I think I might need bigger with my 650s though.

-- Adrian

[RSTurbo]

Adrian, what benefits are there in upgrading fuel pump...other than the safety aspect? Will you get any increase in performance, or possibly better economy? I have your chip with turbo back exhaust and intake mods.

The pump in my car was replaced just before I bought it with a OEM spec one. No idea of the brand though. That was about 20000k's ago.

--Tim

[adrianvos]

Just safety!! you may actually make more power in lean out just before it goes bang!! :(

[virginslayer]

Adrian, if you retain the standard exhaust, OR just go 2.5 inch, will you need to replace the fuel pump with your chip, on the basis the boost is not as high?

[adrianvos]

Fuel flow is about power... not boost. If you make more power at the same AFR, you need more fuel. On this basis, you will not need as much fuel for a stock exhaust, but if it was my car... for under $300 for the Walbro, I would do it.

-- Adrian

[subarursliberty]

Its not the chip that leans the fuel out. You guys running boost cuts with around 16psi of boost should also replace your fuel pumps.