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Discussion Starter · #1 ·
What are the limits of the stock fuel pump?

I have been thinking about running the VF23 or VF30 with STI injectors on the stock fuel pump. There are several people doing this with the VF23. Not so many that I've heard of with the VF30.

I'm sort of a Noob, so I don't know how you tell when the stock fuel pump reaches its limit, or what even happens IF it reaches its limit. I'm sure it's not good.

What PSI do you think I'd be able to push to redline with the stock pump, and is it OK to run this setup without going too crazy with the boost? I am pretty sure the Walbro's flow 255 lph is that right? The stock one flows around 130?

One more thing, what are your thoughts on the Supra fuel pumps? What modifications need to be done to fit them into the WRX?
 

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TurboXS maxed out the stock fuel system (100% injector duty cycle) on the WRX in their initial Stage 3 development. IT was at about 15psi with a VF30.

They were not too happy with that as there was no error margin.

check www.turboxs.com and scroll down to the Stage 3 link.

This was with unichip fuel maps though, not sure whether the stock fuel map provides enough fuelling. My WAG would be no.

Cheers,

Andrew
aussieinstlouis

****WAG = Wild Arse Guess
 

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It seems to me that if one decides to pony up for the $400 injectors, another $100 for a pump isn't so bad a price to pay.

Any reason you don't want to run the pump in conjunction with the turbo and injectors?

I'd been contemplating running the turbo without any fueling mods to save the $400 + $100 in fueling mod costs and the $500-600 in Unichip costs ($1000 total) - but if you're going for the fuel management (ECU) and injectors you might as well spend the last $100 and get the pump...

All IMHO of course. :D
 

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Discussion Starter · #5 ·
aussie,

I agree. I'm just on a fairly tight budget.

Turbo XS maxed out the IDC with stock pump AND stock injectors, but with the right injectors the fuel pump is supposedly able to handle almost 400 hp (Pace helped me with some calculations there)

I will probably end up doing it, but if a bunch of people said that doing just the injectors was OK, then I might hold off until I have the cash.
 

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Modifying cars and tight budgets don't mix. I don't want to be the guy who kills the party here, but if you can't afford a new engine, a rebuild, a transmission, etc, really think hard about bringing your car to that level of performance. If a $100 fuel pump is a concern, I can't understand how your going to pony up when you blow rings, pistons, etc. You are pushing these cars HARD at this level, I don't care what anyone says about it being 'safe'. Remember, safe is subjective. To me it might mean getting a good year (12k miles) out of an engine, to you, it might mean something entirely different. It's really easy to modify these cars, and it's pretty cheap, but when things go wrong, it gets expensive real fast. Just saying think hard, that's all, I don't like to see people pushed into bad positions because of money, and this has really good potential for it. Just looking out for you, trying to be a voice of reason here, it's easy to get caught up in this, god knows I am.

jb
 

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I have heard of a person running the 23 with STi injectors, 18.5 PSi of boost and the stock fuel pump. I have been told by a couple peolpe that you do not have to upgrade the fuel pump. The stocker will work just fine.


-FACTION
 

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Tronner said:
Heard that. Thanks Jim.
Jim is right, you can run with the stockers. But how hard are you going to push the turbo? Taking it to it's limits with out a better fuel system can cause a lean condition. I recommed getting your ecu remapped for your new turbo to exploit it's sweet spot and to have it run more efficiently. A bigger intercooler would also help.


~Octavio
 

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Tronner, congrats on the purchase of your VF30. ;) :D

We'll get that bad boy in at the weekend. I personally feel that you will be ok on the stock pump for a while (it will flow enough, but longevity is a concern), but injectors are a must-have to extract the full potential of this particular 12-second turbo. The TurboXS stage-4 map is extremely conservative. I know this from experience. With the appropriate supporting upgrades, your setup will be 3 miles this side of 'safe'.

You got a piece of history with that turbo! LOL.

;)

-Pace
 
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