WRX center diff trade for STI intake and Throttle body
So... trying to sell off parts and add to my 818 project... this possible trade came up.
Is there any advantage to an STI's TB and intake?
Does a trade seem reasonable if there is?
I just started using Ebay and Craig's list this week, 2 days $300 recovered from the donor...
We will remove the center diff since we won't be using the rear drive assembly of the transaxle... not sure what has to stay in there to button up the transaxle when we remove the end plate and block off the output shaft.
The STi throttle body and intake manifold are "drive by wire" and not by a cable. the 02-05 Impreza and WRX are both cable driven throttle bodys, the STi and 06/07 WRX are both drive by wire so depending on what your donor vehicle is the parts may not fit. and as far as I know the sti bits and 06/07 wrx bits are the same parts, just the intake manifold is painted red.
The STi throttle body and intake manifold are "drive by wire" and not by a cable. the 02-05 Impreza and WRX are both cable driven throttle bodys, the STi and 06/07 WRX are both drive by wire so depending on what your donor vehicle is the parts may not fit. and as far as I know the sti bits and 06/07 wrx bits are the same parts, just the intake manifold is painted red.
hope this helps
all sti are drive by wire? and they are the same size as the stock WRX parts? my donor is an 05
any idea what a used center diff is worth with 70k on it?
sorry man, those parts won't work for you. the drive by cable is set up different from the drive by wire, our wrx setups don't have the wiring or the drive by wire pedal assembly that would be needed. it also wouldn't be a upgrade either...
The V8 intake manifold is for a drive by wire throttle system and will not work with the standard WRX throttle body as is does not have the air bypass port for the idle control valve. The picture shows the WRX throttle body gasket on the V8 intake manifold so you can see there is no bypass port. If you do not have a WRX manifold you may be able to cut a bypass port into the V8 manifold.
2004 WRX w/ 300whp soon to be 818 donor... well thats the plan anyways
Quick guideline for USDM turbo Subarus (post '94):
2.0 liter = Cable throttle and 16 bit ECU
2.5 liter = Fly by wire and 32 bit ECU
Jdm sti v7,v8v9 are drive by cable, and have no tgv valves which you will want to delete if you had them. This is what you want, they are the best solution
And you can use your ecu, or a better jdm sti 32 bit one if you wanted.
Maybe possible to use an 06 WRX ECU? I'm not sure how different the sensors are but if people are doing hybrids of the 2.0/2.5 I don't see why not as far as the ECU goes. Comes down to if you want DBW or DBC. Personally huge fan of DBW, hate DBC. But do check with a tuner first to make sure ECU will work fine with the 05 engine.
The *general* rule is that the ECU matches the heads/intake manifold. The block underneath is inconsequential (once tuned for it). There are tons of exceptions, of course, but those are already covered as-nauseum on multiple Subaru boards.
You can run some AVCS heads with the older non-AVCS 16bit cable throttle ECU, but you disable the AVCS in the process.
You cannot run non-AVCS heads with the newer 32bit ECU unless you turn off CEL codes. But what then is the point of swapping to a 32 bit ECU?
There can also be cam timing issues when doing some hybrids that need to be worked out. Brackets are commercially available to properly relocate the cam sensor for some combos.
The ECU must match your harness. So if the donor is an '05 2.0 liter WRX you would need to source a different harness to run the DBW throttle. (At what point would it become better to just trade up for a DBW donor?)
IMHO, unless your fairly well versed in the details keep the heads/intake/throttle/ECU/harness all matched and treat any upgrades like you would if the motor was installed in a stock WRX of your harness year.
Thanks for all the knowledge! I'll just stick with my current intake and TB
Anyone ave an idea of the value of a good center diff? I'm guessing $200 or so...
Humm, 200 bucks is pretty good. New ones from the dealer go for 400-500.
Aside from the 16 bit ecu (which in some ways is also more desirable than the 32 bit), the old-fashioned cable throttle is more desirable than the newer drive by wire systems. Tuning DBW is a pain and you wouldn't believe the overly complicated bass-akward ways of mapping the throttle in some of the more recent years. Rarely is your foot actually matching what the throttle does, even at WOT the ecu is changing throttle % based on crap like intake temp, gear, speed etc.
I am of the opinion that the 2L engine will feel much better on the 818 anyway and with a cable throttle and simple and trusty 16 bit ECU you can just focus on the fun stuff.
does the intake of the STI flow better and will a wrx throttle body bolt to a STI intake? The photo that I've seen shows what looks like the same throttle belcrank
does the intake of the STI flow better and will a wrx throttle body bolt to a STI intake? The photo that I've seen shows what looks like the same throttle belcrank
No, the STI intake is just a painted WRX intake. In fact, the Forester XT and Legacy GT's intakes are also identical. Yes, the WRX throttle body will bolt to a STI intake.
I'd just recommend taking your WRX intake and painting it with nice engine paint or even having it powder coated if you want an STI intake. Much cheaper.
The MAIN engine/power parts you want to swap/mod are these 5 things.
1 Turbo: Upgrading to something better than the TD04. A cheap option is just a used VF series turbo off an STI Or an HTA 68 or used 16 or 18g turbo for the 2L. A 20G could feel quite nice on a 2L on the 818 because of the better top end. Spool will certainly be slower after shaving 1500 lbs of weight for the 818 on any turbo but that COULD be a good thing as I expect traction will become a big challenge on the 818 and you won't want rapid spool and torque delivery off the line.
2. A walboro 255 or better fuel pump
3. Catless up-pipe and a catless or high-flow catted downpipe
4. And of course, a quality tune.
Optional but recommended for power:
STI intercooler or better to replace the stock WRX one but I'd wait to see what FFR comes up with as there might be another option that trumps any top mount.
I also recommend TGV deletes to improve intake flow but everything above is more important.
Transmission won't matter for the 818, the 6 speed is not only un-compatible for a stock 818 chassis but it's heavier and it's shorter ratios are going to be a problem on a car as light as the 818. A PPG upgraded 5 speed with taller gears would be ideal.
Brakes: For the 818 the stock 02-05 slider brakes are fine especially if you mod the rears to use H6 rotors. I think the 06/07 wrx 4 pot front and 2 pot rears will be the best fit for the 818, they'll have the best blend of weight, balance looks and performance IMO. The STI brembo's are just a tad large for the 818 for autocross or spirited street use, most courses aren't long enough to get the heat needed for good performance pads. I'd swap them for smaller brakes and use the cash on wheels/tires or performance mods unless your 818 was a full on track car.
No, the STI intake is just a painted WRX intake. In fact, the Forester XT and Legacy GT's intakes are also identical. Yes, the WRX throttle body will bolt to a STI intake.....
I thought previous posts have indicated that the WRXs have TGVs while STIs do not? Also the Legacy GT has a plastic intake manifold with the throttlebody kinda tucked under it, not the aluminum one with the throttle entering rear and center like the WRX and STI.
I thought previous posts have indicated that the WRXs have TGVs while STIs do not? Also the Legacy GT has a plastic intake manifold with the throttlebody kinda tucked under it, not the aluminum one with the throttle entering rear and center like the WRX and STI.
Unless your talking post-'07 WRXs?
Yes, you're right about the plastic intake and integrated throttle body on legacy turbo models, my mistake. The NA ones have aluminum ones so I got mixed up having been into my new Chilton manual for mu 00-06 outback/forester last night :-P
JDM versions don't have them. That article says the JDM TGV's don't have the butterfly valves or the dividers. That's what makes a TGV (tumble generator valve) a TGV so the JDM models just have that section as a separate spacer for the injectors. Newer JDM ones might have them though but I'm not sure.
No, the STI intake is just a painted WRX intake. In fact, the Forester XT and Legacy GT's intakes are also identical. Yes, the WRX throttle body will bolt to a STI intake.
I'd just recommend taking your WRX intake and painting it with nice engine paint or even having it powder coated if you want an STI intake. Much cheaper.
Legacy GT and Forester XT have the plastic manifold with the inlet tucked under the manifold. GD WRX intake manifold is the same as the STi yes.
STI intercooler or better to replace the stock WRX one but I'd wait to see what FFR comes up with as there might be another option that trumps any top mount.
Great info in this thread!
2 things lead me to believe FFR will stick with the top mount:
1. The kit price of $9900
2. The fact that AJW is offering an upgraded top mount with their stage 2 kit (it wouldn't make sense to do that if there were a better option for the 818)
Other than the STI, the manifolds changed to plastic on the generational changes.
WRX:
'02-'07 Aluminum
'08+ Plastic
STI:
'04-'07 Aluminum
'08+ Aluminum
Baja:
'04-'06 Aluminum
Forester:
'04-'08 Aluminum
'09+ Plastic
Legacy/Outback
'05-'09 Plastic
'10+ New style front mount turbo
All aluminum manifolds have the traditional center-mounted, rearward-facing throttlebody and a tradtional "slip" type of turbo outlet.
All plastic manifolds have the low, offset mounted throttlebody and a flanged turbo outlet that bolts directly to the intercooler. (outside of the '10+ Legacy)
Just to be complete...all were 2.5 liter and have DBW throttles except '02-'05 WRX which is 2.0 and cable throttle.
I *believe* all the DBW cars (outside of '08+ STI) are electrically compatable as I have seen Legacies and Foresters converted from plastic manifolds to Aluminum to use upgraded WRX/STI intercoolers or front-mount kits.
Of course all the above only applies to turbo motors. Edit: And only to the North American market cars.
Other than the STI, the manifolds changed to plastic on the generational changes.
WRX:
'02-'07 Aluminum
'08+ Plastic
STI:
'04-'07 Aluminum
'08+ Aluminum
Baja:
'04-'06 Aluminum
Forester:
'04-'08 Aluminum
'09+ Plastic
Legacy/Outback
'05-'09 Plastic
'10+ New style front mount turbo
All aluminum manifolds have the traditional center-mounted, rearward-facing throttlebody and a tradtional "slip" type of turbo outlet.
All plastic manifolds have the low, offset mounted throttlebody and a flanged turbo outlet that bolts directly to the intercooler. (outside of the '10+ Legacy)
Just to be complete...all were 2.5 liter and have DBW throttles except '02-'05 WRX which is 2.0 and cable throttle.
I *believe* all the DBW cars (outside of '08+ STI) are electrically compatable as I have seen Legacies and Foresters converted from plastic manifolds to Aluminum to use upgraded WRX/STI intercoolers or front-mount kits.
Of course all the above only applies to turbo motors.
*boom*
...and that's why PhyrraM is the Bob Vila of Subarus
Thanks for more great info!
so he wants to trade me a painted intake (STI) and a WRX TB since it has the cable pulleys/bellcranks...
I'm powdercoating stuff soon... almost eerything is off (brackets, valve covers, oil pan etc... ) except the intake. I'm going to finish the bottom stuff, bolt on the oil pump and header before I rotate her and do the top
My BIG problem:
Color to powdercoat! I like black wrinkle valve covers and it would go with anything but some bright color to POP would be sweet... metallic red, copper mettalic, simple semi gloss black as I expect to get for the powder coated frame...
It's hard when you don't know what body colors will be available!
thoughts????
I settled on the ceramic coated header from AJW with non cat up pipe (included) I plan on using the stock downpipe as my 220 HP goal should be easy with the header and a tune... I have an AEM intake though who knows what will work with the 818... I'm trying to find a local shop to do the Quaife LSD...
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Originally Posted by RCKSTR
