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Discussion Starter · #1 ·
I just picked-up my car with a freshly installed VF35. You can see my list of mods below my name, but keep in mind that the stock ECU has not been reflashed yet, nor has the fuel pump/injectors been upgraded. The shop is supposed to have the ECU software in January. The fuel upgrade will obviously be done at the same time.

Since I picked it up during lunch at work, I wasn't able to really test it thoroughly, especially with regard to high-end power.

But, all that being said, the difference I did notice versus the stock was that the power delivery seemed more smooth and kept going strong into the higher rpms with comparatively little fall off.

I did not notice any significant (ala "butt dyno") increase in power over the stock turbo, but I am only running boost at .5 bar with the VF35, and not 1.1 bar as I was doing previously with the stock unit. The shop advised me to leave off my EBC until the ECU reflash and fuel upgrade are performed. Although I'm anxious to turn up the boost a bit, I won't risk it.

Hopefully the performance will increase over the next couple of days as the computer learns.

Darin
 

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Discussion Starter · #4 ·
Thanks for the encouraging works, Jim.

I was able to drive a bit more last night (buying lots of presents for Christmas!), and noticed that the overall power feels fairly equal to the stock, probably more in a few areas, espcially in the higher RPMS, but again, I'm running half the boost I was before.

So, I'd imagine I'll be able to get a hell of a lot more power with the ECU reflash, proper fuel system, and 1.1-1.2 bars of boost.

The power does feel very solid and smooth. The spool is great too. I wound it up a few times last night and was really surprised at the power that came through with a good spool-up. Definitely stronger than the stock!

It kills me that my shop doesn't have the reflash program yet, despite the fact that others, like Vishnu, do. They said it'll be January or February before they get the legal details worked out and can start using.

Darin
 

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Believe it or not, you can run bigger turbos on stock fuel at 15-17psi. Just make sure you do lots of data collection and go incrementally.

-C
 

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You are going to hear a lot of paranoid delusional opinions on here of people who have not done it. I have a VF-35, running stock ECU, i was running with stock injectors and stock fuel pump at 16psi NO PROBLEM... I am now running a fuel cut defender with a holley pump stock ECU stock injectors at 18 PSI. NO problems at all.. What other mods do you have?? your stock injectors can handle a vf-35 at 18 psi no problem. Period :)

Dont believe the paranoid hype ;)!!! start enjoying that thing like your suppsoed to.. The differance in 15 and 18psi is INCREDIBLE.


Rob
 

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Discussion Starter · #8 ·
Rob, believe me, I'm dying to crank up the boost! I naturally assumed if the shop tells me to not do it, then I shouldn't.

I would imagine they told me to turn it off to prevent any potential overboosting, and didn't want to rely on my common sense.

Please check my mods below my name, and confirm if you (or anyone else) things there's *no way in hell* I could hurt my engine by increasing the boost to 15 psi / 1 bar.

Thanks!

Darin
 

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Don't top 1 bar with the stock ECU and stock fuel. RobPA's right about the stock fuel being enough to get by at that pressure, but you won't want to run more than that on the stock ECU. With your mods at 1 bar on the stock ECU you'll be around 250whp, so you're OK as far as fuel goes, though not by a whole lot. Start cranking that boost without the stock ECU being programed or chipped for it and you might run into long term problems. It's your engine, but I'd lean on the safe side if I were you. I will not run mine if it isn't tuned for what mods I have, period.

1 bar will be fine, but I sure wouldn't push it past that, in fact, I'd lean toward .85 or .9 bar rather than a full bar. I cannot afford to compromise reliability, so this advice represents the conservative side - it's what I'd do. But it's your motor; if you wanna gamble on 18 psi, go ahead. You'll probably be fine (at least in the short term), but it's your wallet in the firing line if anything goes wrong. I certainly wouldn't past 1 bar.
 

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Discussion Starter · #10 ·
Thanks Stiles. There's no way I'd boost to 16 psi, let alone 18, without the appropriate ECU mods. I prefer to go conservative, as it's not always obvious when the engine gets damaged.

So, how about .7 bar? It's only .2 above what I'm doing now. Shouldn't that still be conservative?

By the way, does anyone know of any shops in Southern California that have the Ecutek software available for the stock ECU reprogram?

Darin
 

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I'm on another level of paranoid when it comes to most WRX owners (mostly because I flat out CAN'T afford to have ANYTHING go wrong), so I don't tickle the dragon's tail without a bazooka near by.:) Going up to .7 would be absolutely fine; same with .8, .9, and probably 1 bar. After that, odds are you'll still be perfectly fine, but they are odds - however small, there is a chance for problems. I won't risk something like that, I guess I'd go to .9 and enjoy the added power. It'll be a nice taste of what's to come when you get the fuel and tuning upgrades!:D

Glad you're enjoying the VF35 DTsRex! It's only gonna get better! I'm really interested in how this turns out, if this turbo give you a ton more power and does it with a minimal increase in lag, I think I'll be considering it when I swap turbos this summer. When you say stuff like 'it's just as powerful if not more than the stock turbo' and you're running it on the stock ECU with no fuel upgrades and only half a bar of boost, I get really excited!:D
 

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Discussion Starter · #12 ·
The boost is running at .6 bar without the EBC on now. When I picked it up from the shop, I was only able to get it to .5 bar when I hit it. Is it possible the computer learned something and the boost crept up? Or, maybe it's just that I'm driving it different and it's causing the boost to creep up slightly.

Anyway, I've been able to really wind it up several times now and I still say it has more power at only .6 bar than when I ran the stock turbo and EBC at 1 bar. The power is simply more solid throughout the rpm range, pulling very nicely.

I spoke with Suby Specialties in Monrovia, CA, and was told to absolutely leave the EBC off. He said that I may think that everything's fine but there will likely be some engine damage if I turn the boost up a bit. He said he had 3 engines sitting in his shop from cars belonging to people who got greedy. By the way, Suby Specialties seem like great guys. Super nice and helpful on the phone.

Regarding turbo lag, I guess it must be increased compared to the stock, but I honestly do not notice it at all. If anyone's concerned about limiting lag, the VF35 fits the bill. It just remains to be seen exactly how much power I'm going to get out of this with the right ECU program and fuel upgrade. I get nervous when my shop says, "Oh, we should have the ECU program January or February, or so...". I see that Vishnu has the new program, but I'm not aware of anyone in Southern California who does. Vishnu is unfortunately 383 miles away from me. Hmmmm, short road trip?

Darin
 

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is 1bar on a vf35 all that much greater than 1bar on a stock td-04 with an EBC? that's cool if it is

and yes, i'd probably listen to steve or whoever told you that over there, or at least not push it, maybe .7 is enough, no reason to go higher if you're getting the rest soon anyways

i'm probably gonna call subyspecialties to get my uppipe and downpipe in, finally got it last night but it's christmas and they're closed for the week i think

im just debating on whether it's worth the extra cash to have them do it there or to just do it at SpeedFactory in La Puente for $70 less($200 vs 270 for the pair)

both good shops, one is subaru-knowledgable and the other i hear does very good work overall


woah, i totally went off topic on this post :)
 

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Rob,

I'd be careful running 18psi on the stock injectors. We should check your fuel injector duty cycle. I do think it's fine because you took care of the two main problems: FCD and the stock fuel pump.

The stock fuel pump actually maxes out before the stock injectors and with a little more pressure, you should be fine.

Call me sometime when you can talk about that FCD, Rob. ;)

-Jim
 

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You're smart to take their advice DTsRex. It sounds like they know their stuff and have three motors to prove it. Again, you'd probably be OK raising the boost, but think how sick you'd be if anything happened. Why chance it? I think it's a good idea to stay on the conservative side of the most conservative advice you can get, just to be sure.

That is unless someone tells you that it's safest not to mod the car at all. Don't listen to those fools.......:D
 

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DTsRex said:
What mods?

I'm merely righting the wrongs. :p
That's the best way I've heard it put.
 

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Stock injectors, with a Vf-35 at 18 PSI, my injector duty cycle is not going past 85%. Spraying at 16psi with a boost spike to 18 psi not going past 88% duty cycle. I also do not have the money for a new engine, hence why i would never give anyone on here advice that would run injector duty cycle any farther then 95%.. which it isint even close to. Bottom Line: the Vf-35 isint that big of a turbo, Cranking the boost up to 1 bar is the least of your worries, id be more worried that its being taken to the "edge" if you were trying to run 19 or so psi :)


Rob
 

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Discussion Starter · #19 · (Edited)
Rob -- you're making my fingers itchy to turn up the boost!! You talks how I likes! :D

(Actually, I tried ran it a few times today with the boost at .8 bar and it was great! Makes me even more anxious to complete the ECU/fuel upgrade.)
 
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