Topic: Turbo back / need tune?

[NiceEqualLengths]

I've got an axle back on my 97 GC8. I want to do a invidia TBE cat less. I know on the USDM you need a tune when you do this, same with the JDM? What the down side of not tuning after a TBE?

[Vicar]

You'll need a tune

VEX has  an inexpensive PowerFC tune option Jimmy likes

[600rr]

You'll need a tune

VEX has  an inexpensive PowerFC tune option Jimmy likes

Hey Jonny,

Can Jimmy tune the higher compression ej20g found in a stb forester via powerfc?

[StickyTires]

Hey Jonny,

Can Jimmy tune the higher compression ej20g found in a stb forester via powerfc?

Ask jimmy himself man. Hes on the forum: jimmy@vex. Send him a pm, should be happy to help! My guess is if there is an fc for that engine he will be able to tune it.

Sent from my SGH-I317M using Tapatalk 2

[GC8REX]

I've got an axle back on my 97 GC8. I want to do a invidia TBE cat less. I know on the USDM you need a tune when you do this, same with the JDM? What the down side of not tuning after a TBE?

the gc's aren't near as picky as the usdms when it comes to mods I've found. I would say pick up a wodeband (good to have anyway), and go ahead installing the exhaust. You'll be able to make sure your afrs are good with whatever mod you do. There may be the occasional backfire with a TBE however.

That being said, you won't notice the full benefits of a tbe without a tune. I'd consider whether you want to drop a ton of money on power fc and tune or just install the exhaust and wideband for the time being . 

[purdy]

A lot of guys have been fine with running a tbe and no tune. GC's are more able to adapt then usdm like GC8REX said. Obvs you're not going to get the full potential of power without a tune. I'd get it tuned just to be safe

[600rr]

Ask jimmy himself man. Hes on the forum: jimmy@vex. Send him a pm, should be happy to help! My guess is if there is an fc for that engine he will be able to tune it.

Sent from my SGH-I317M using Tapatalk 2

Dont worry, I know Jimmy personally lol. I just thought Jonny was online and therefore would be able to add input sooner than Jimmy would.

[Jarrod]

Little off topic but I'd be curious to hear about the forester with power fc.
I did a lot of digging and it appears that there is no easy way to tune the early JDM foresters.  The 00-01 is when OBD2 started (?) and there are tactrix cables and such for tuning there I think.

I did a lot of digging and basically found that the forester has the ej20k ecu and identical wiring.  I e-mailed Rob to get some input as he's currently working on the ej20k tune but because the foresters have 9.0 compression, he said his tune would not work for the forester (something about dangerously close to knocking).  He also said he had no intention of making/modifying his tune for the forester

Anyone know much about compression, I have to learn still.  I read that going to a different sized head gasket could change that?  Just thinking if someone did swap head gaskets to match compression, the tune could be applied then.  I'm not sure what the 20k is, 8:1?  Is it possible to go from 9 to 8?

[NiceEqualLengths]

Going to reply to all messages in order, all at once so I don't spam.

VEX has  an inexpensive PowerFC tune option Jimmy likes

If I recall Stickytires did his set up for 2200 ($?) for tune and setup.
While this would probably be the best setup, don't have the balla cash to drop that much right now.

I know that I won't notice a big gain, but I'm just waiting for a Robs Tune to come out. (Soon I hope)
I just didn't want to run rich or worse, lean. As long as there isnt a check engine light on ALL THE TIME, i'll be good.

Picking up a Wideband stubbornly. Reading your thread Tom made my brother pick one up for is SR.

Jarrod, a thicker head gasket would decrease compression because you're increasing the CC of the chamber. IIRC.
There was a site I used when I built my V8 so I didn't get crazy valve interference.
http://www.csgnetwork.com/compcalc.html

Another option would be decreasing the height of the piston. But that's either machining the itshay out it, or AM pistons.

Best option? Don't know. I'd look for the thickest gasket and do some math??

[goodveet]

I've been running a catless dp for months. No backfire or anything. Engine hasn't blown up yet either.

[goodveet]

Oh, and no CEL ALL THE TIME. Matter of fact, no CEL ever.

[LilDrunkenSmurf]

Oh, and no CEL ALL THE TIME. Matter of fact, no CEL ever.

Burnt out..

[Jarrod]

I don't think the K will require a tune just because of the exhaust but hey what do I know.
Do they have the black diagnostic plugs?  Could hook those up to see if your light works at least 

[goodveet]

My light works. I know because I started the car with MAF unplugged once by accident 

[Jimmy@Vex]

Yes, it's critical to have a tune when you're running a TBE.

Burnt out..

Lol.

[Jimmy@Vex]

Little off topic but I'd be curious to hear about the forester with power fc.
I did a lot of digging and it appears that there is no easy way to tune the early JDM foresters.  The 00-01 is when OBD2 started (?) and there are tactrix cables and such for tuning there I think.

I did a lot of digging and basically found that the forester has the ej20k ecu and identical wiring.  I e-mailed Rob to get some input as he's currently working on the ej20k tune but because the foresters have 9.0 compression, he said his tune would not work for the forester (something about dangerously close to knocking).  He also said he had no intention of making/modifying his tune for the forester

Anyone know much about compression, I have to learn still.  I read that going to a different sized head gasket could change that?  Just thinking if someone did swap head gaskets to match compression, the tune could be applied then.  I'm not sure what the 20k is, 8:1?  Is it possible to go from 9 to 8?

If the wiring is the same for the Foresters and they run the same ECU as Impreza, then we should be able to plug in a Power FC and tune it. If not we can always wire up a Haltech

Compression won't matter for my tunes, as I tune every car from scratch and optimize the timing across the board anyways.

[Jarrod]

Do we have any idea what kind of power the ej20K can make with mods like the 550 tunes?  Injectors, intake, exhaust... fmic?  Stock turbo I suppose and no rebuild (for those that tune with aftermarket ecu's).  We have all heard that the 550 tune is about as much as you can get out of the ej20G.
I'm wondering what the aftermarket ecu's can do that Rob can't or if they should basically be on par.  Then I think about, would it be cheaper to get a forester and do some mods to the heads or swap out the block for the lower compression as opposed to buying a $1000 ecu and spending X amount of dollars tuning it, only to find it's not putting out as much as Rob's tune.

Oh the possibilities 

[goodveet]

Let's convince stickytires into being the guinea pig 

[Jesse.Korpan]

Ill do it

[Jimmy@Vex]

Do we have any idea what kind of power the ej20K can make with mods like the 550 tunes?  Injectors, intake, exhaust... fmic?  Stock turbo I suppose and no rebuild (for those that tune with aftermarket ecu's).  We have all heard that the 550 tune is about as much as you can get out of the ej20G.
I'm wondering what the aftermarket ecu's can do that Rob can't or if they should basically be on par.  Then I think about, would it be cheaper to get a forester and do some mods to the heads or swap out the block for the lower compression as opposed to buying a $1000 ecu and spending X amount of dollars tuning it, only to find it's not putting out as much as Rob's tune.

Oh the possibilities 

Lol, no ones ever dyno'd a Robs tune locally. And I highly doubt his e-tunes are putting down as much power, or as optimized as my real tune in house.....there is no possible way, every car is different, there is no magical map that will fetch the most power out of every car. That's like comparing sunny's pro tune to a Cobb stage 2 shelf map.

That being said, if anyone wants to Dyno their robs tune email or pm me and I'll give you a good deal on base lining it.

[Jarrod]

For argument's sake, let's pretend that Rob's 550 tune does put down ~280hp to the wheels.  Has anyone at Vex gotten something similar with the same supporting mods but different tuning methods (aftermarket ecu)?  I guess I'm curious what sorts of tunes to ej20g's you guys have done as I don't know where I could find that kind of info.  What about the ej20k's in imprezas and foresters?  Have you guys tuned those and if so with what mods and results have you seen?
Does anyone know about Sunny on these engines as well?

With more info like that, I could think about what kinds of paths I want to go down.
Any help from anyone is appreciated!

[Jimmy@Vex]

While engine design does effect power and efficiency we haven't noticed huge differences between the 92-97 Subaru's unless the turbos/ecu's are different.  Even with alternate tunes and ECU's the limitations of the power we make is usually more from intercooler or turbo size than the engine family. 

Realistically... the best approach to testing is going be a direct comparison on the same dyno, with a car that is running good with a robs tune, all other talk is just assumptions and estimates. 

We typically see around 220-250whp on JDM Subaru's with turbo-back exhausts, intakes, and a decent tune.  We keep our tunes safe as we don't want our cars tuned to the edge. We are tuning street cars that need to last as long as possible, but still make maximum safe power. 

As for other JDM Impreza's and foresters, not to many guys go through the efforts and costs involved in getting the cars tuned, so there is not a lot of them around in Calgary for comparisons.