STI with just a UTEC or UTEC+VF34......

RoC_Pooh · 08-06-2004, 03:40 PM

What kind of performance it will gain with just the UTEC or UTEC+ a VF34 on a 05 STI without any other mods?

I know I read most people want or suggest a TBE but I really don't like the idea of TBE or just swap the muffler.

Thanks

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RoC_Pooh · 08-09-2004, 02:11 PM

anyone?

happasaiyan · 08-09-2004, 02:15 PM

probably a good 40whp or so. thats my edjucated guess.

big_adventure · 08-09-2004, 02:22 PM

You will be really, really limited by the exhaust backpressure with two cats meowing behind the turbo. I HIGHLY doubt that a UTEC alone will give you a consistent 40whp on an STi.

-Sean

happasaiyan · 08-09-2004, 04:32 PM

Quote:

Originally Posted by big_adventure

You will be really, really limited by the exhaust backpressure with two cats meowing behind the turbo. I HIGHLY doubt that a UTEC alone will give you a consistent 40whp on an STi.

-Sean

i think the utec alone would yield 25-30whp...and then an extra 10-15whp more topend on the vf34 vs vf39. thats my guess.

hippy · 08-09-2004, 07:05 PM

I wouldn't think it's worth getting a vf34 given the turbo you're starting with is so close in size.

big_adventure · 08-10-2004, 08:59 AM

People seem to have mixed results with the vf34/39 transfers. The vf34 should hold a little more boost to redline than the 39, thanks to the larger exhaust side, and flow a little bit better up there, but you're maxing and going beyond maxing both of those turbos on that engine. If you are going to upgrade the STi turbo, go for AT LEAST a vf22 or 18g. Otherwise, the upgrade may not be worth the price of a new uppipe gasket.

-Sean

Subiemax · 08-12-2004, 09:59 PM

I would also like a backed up answer to this question.
I want a little more hp and smoother acceleration for my sti.
But want to be able to go back to stock if I need service.
Anyone with first hand experience with UTEC on stock STI.
"NMYETI" or maybe "TurboXS(Pete)"

Abe Froman · 08-13-2004, 07:48 AM

My car had only a catback on it when I got my UTEC. Are you willing to tune it yourself? If not your gains will be minimal(it's not really plug and play).

Mostly stock, what you will really gain with the UTEC is torque, I upped the boost on my car to 19psi(+5) tapering down to 14ish(+2) with zero knock on 93 octane with some self tuning of timing. With the stock ECU in control I was getting 14ish peak tapering down to 12ish. The VF39 really doesn't like to hold boost near redline and I don't like to force it so I let it taper the way it wants to. With the stock fuel curve your injectors will be running a high duty cycle.

In layman's terms the gains come mostly in midrange torque and drivability, the power comes on smooth and it pulls from lower rpms with much more authority but you will likely have hesitation issues near the transition point from ECU to UTEC and back to ECU(I did).

If your willing to shell out $ for a proper tuning(or tune it yourself like I did) the hesitation issues can be lessened and I would say 25hp is reasonable w/tuning but the torque is the real gain and it's easy to get with minimal tuning.

Oh and flat shifting is so much fun it's almost worth the price of the UTEC alone...ok maybe not but it's a blast!!

Hope that helps.

Zornorph · 08-13-2004, 08:18 PM

did you check the thread about 50% of sti's coming with the 18 hot side? It is a VF34!

TheMadScientist · 08-14-2004, 07:35 AM

If you are going to upgrade the turbo on an Sti. Stay away from the IHI junk. Go get a real turbo. MHI, garrett, rotomaster, anything other than IHI.

My $0.02

TMS

xtian67 · 08-14-2004, 12:13 PM

Quote:

Originally Posted by Zornorph

did you check the thread about 50% of sti's coming with the 18 hot side? It is a VF34!

Link please!

Abe Froman · 08-14-2004, 04:44 PM

Quote:

Originally Posted by xtian67

Link please!

Not quite 50% but pretty freaking high!!

http://forums.nasioc.com/forums/showthread.php?t=606432

08-06-2004, 03:40 PM	#1
RoC_Pooh Scooby Newbie Member#: 66450 Join Date: Jul 2004	STI with just a UTEC or UTEC+VF34...... What kind of performance it will gain with just the UTEC or UTEC+ a VF34 on a 05 STI without any other mods? I know I read most people want or suggest a TBE but I really don't like the idea of TBE or just swap the muffler. Thanks * Registered users of the site do not see these ads.

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08-09-2004, 02:11 PM	#2
RoC_Pooh Scooby Newbie Member#: 66450 Join Date: Jul 2004	anyone?

08-09-2004, 02:15 PM	#3
happasaiyan Scooby Specialist Member#: 37731 Join Date: Jun 2003 Chapter/Region: MWSOC Location: Rolling Meadows, IL Vehicle: '07 TL-S 6MT '07 RDX-T	probably a good 40whp or so. thats my edjucated guess.

08-09-2004, 02:22 PM	#4
big_adventure Scooby Specialist Member#: 40501 Join Date: Jul 2003 Location: Paris, FR Vehicle: 2005 Decathalon 21sp One WheelSeanPower	You will be really, really limited by the exhaust backpressure with two cats meowing behind the turbo. I HIGHLY doubt that a UTEC alone will give you a consistent 40whp on an STi. -Sean

08-09-2004, 07:05 PM	#6
hippy Scooby Specialist Member#: 36528 Join Date: May 2003 Location: florida Vehicle: 2002 Impreza Wrx Silver	I wouldn't think it's worth getting a vf34 given the turbo you're starting with is so close in size.

08-10-2004, 08:59 AM	#7
big_adventure Scooby Specialist Member#: 40501 Join Date: Jul 2003 Location: Paris, FR Vehicle: 2005 Decathalon 21sp One WheelSeanPower	People seem to have mixed results with the vf34/39 transfers. The vf34 should hold a little more boost to redline than the 39, thanks to the larger exhaust side, and flow a little bit better up there, but you're maxing and going beyond maxing both of those turbos on that engine. If you are going to upgrade the STi turbo, go for AT LEAST a vf22 or 18g. Otherwise, the upgrade may not be worth the price of a new uppipe gasket. -Sean

08-12-2004, 09:59 PM	#8
Subiemax Scooby Specialist Member#: 30691 Join Date: Dec 2002 Chapter/Region: South East Location: Paulina, LA Vehicle: 2013 FRS RED	I would also like a backed up answer to this question. I want a little more hp and smoother acceleration for my sti. But want to be able to go back to stock if I need service. Anyone with first hand experience with UTEC on stock STI. "NMYETI" or maybe "TurboXS(Pete)"

08-13-2004, 07:48 AM	#9
Abe Froman Scooby Specialist Member#: 22309 Join Date: Aug 2002 Chapter/Region: MAIC Location: Northern Virginia Vehicle: 04 STI 05 LGT Wagon	My car had only a catback on it when I got my UTEC. Are you willing to tune it yourself? If not your gains will be minimal(it's not really plug and play). Mostly stock, what you will really gain with the UTEC is torque, I upped the boost on my car to 19psi(+5) tapering down to 14ish(+2) with zero knock on 93 octane with some self tuning of timing. With the stock ECU in control I was getting 14ish peak tapering down to 12ish. The VF39 really doesn't like to hold boost near redline and I don't like to force it so I let it taper the way it wants to. With the stock fuel curve your injectors will be running a high duty cycle. In layman's terms the gains come mostly in midrange torque and drivability, the power comes on smooth and it pulls from lower rpms with much more authority but you will likely have hesitation issues near the transition point from ECU to UTEC and back to ECU(I did). If your willing to shell out $ for a proper tuning(or tune it yourself like I did) the hesitation issues can be lessened and I would say 25hp is reasonable w/tuning but the torque is the real gain and it's easy to get with minimal tuning. Oh and flat shifting is so much fun it's almost worth the price of the UTEC alone...ok maybe not but it's a blast!! Hope that helps.

08-13-2004, 08:18 PM	#10
Zornorph Scooby Specialist Member#: 17332 Join Date: Apr 2002 Chapter/Region: NESIC Location: The neighbor's yard Vehicle: 2004 Black STI Not stock anymore	did you check the thread about 50% of sti's coming with the 18 hot side? It is a VF34!

08-14-2004, 07:35 AM	#11
TheMadScientist Scooby Guru Member#: 23717 Join Date: Aug 2002 Chapter/Region: NESIC Location: Beverly, MA Vehicle: 2005 Big red	If you are going to upgrade the turbo on an Sti. Stay away from the IHI junk. Go get a real turbo. MHI, garrett, rotomaster, anything other than IHI. My $0.02 TMS