New GC8 99 Owner .... Mods

Androo26
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Re: New GC8 99 Owner .... Mods

Postby Androo26 » Mon May 08, 2017 10:07 am

Rightio the baseline run has been done as I dropped the car off, modded on the stock ecu untuned. Here it is. Although its only running 13psi its good to see that it holds that boost all the way to the end.

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mv75
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Re: New GC8 99 Owner .... Mods

Postby mv75 » Mon May 08, 2017 4:35 pm

Androo26 wrote:Yeah the tuner did ask me if I was going to run one ( he didnt ask why or try to talk me out of it so who knows )... but seeing as though the Haltech is map sensor based and Im only going to be running 15 psi , I dont see the point. I love the way it sounds as is.

In your case the Bov was lifting off its seat at 18psi and venting... Cheers for clearing that up.


Cool, you got mafless. Good choice for that year. I went through 3 maf sensors when I had my gc8. Real crap those ones were. Went two subarus and I sold it with a Nissan one. The ones on these later models are way better. I can go mafless if I want, but I'm sticking with maf for now, especially since I've finally got it running sweet as of yesterday. Got the larger intake running great. :)

The chart really does put it where I expected. Runs out of puff @ 100km/h. If you're after more, and really want that sweet here comes the boom hold on thump, get a vf34. :) But it's understandable if you want to keep it closer to stock. Well, it's doing better than stock anyway. :) Good charts anyway, that peak power was in 4th, so that peak In 2nd you'd be flogging to that peak torque easily.

Looking good. :) Get that intake hose yet?

Androo26
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Re: New GC8 99 Owner .... Mods

Postby Androo26 » Mon May 08, 2017 11:23 pm

Intake hose... Nope , havnt heard from them. Im not going to change it now as it will be tuned using the one I made up. Just out of interest what wheel kw does the stock GC8 fuel system top out at ?

I wish the chart showed engine RPM but I guess ill have to work it out when in 4th gear. If I had wanted 180-200kw I would have gone a VF34 for sure. Im sure ill be happy with what power it makes on this one...... for 5 minutes lol.

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Delivan
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Re: New GC8 99 Owner .... Mods

Postby Delivan » Tue May 09, 2017 12:00 am

I think a stock gc8 rex is around 128 kwatw . I think the small diameter pipe you have used in both the IC "Y" and the intake pipe have slowed the flow quite a bit, especially the intake. I think the few kwts you have gained is mainly due to getting rid of the resonator and it's pipe work, although well done, the pipe is way too small to make any gain in power. The stock intake gradually reduces in size. By going from 3"+ down to 2", which in volume is almost half, within such a short distance is detrimental to flow. A gradual decrease is a lot better. Replicating the original pipe in similar sizes and reducing gradually but keeping it as big as possible and by making the section that goes under the manifold bigger by squashing a section of 3" into an oblong shape you would have retained the same capacity of flow as the original. There is also now no stretch in the intake so when the engine twists to one side on it's mounts under acceleration, you risk pulling the hose of the AFM housing... This is the reason people who want better flow go for a silicon pipe like this one that is almost 4" in diameter and fills the entire space under the manifold , not just a small round section under there. That intake is way too small and if you add a bigger turbo it will not perform any better because it is going to be sucking it's little heart out trying to get air in through such a small intake hose..
Using this calculator to find volume and therefore FLOW ..http://www.matthewb.id.au/converter/cyl ... lator.html The volume of a 2" pipe 10" long compared to a 4"pipe 10" long is approx .5 of a liter in 2" pipe compared with almost 2 liters in a 4 " cylinder...I know this diameter is reduced slightly when going under the manifold but even an oblong 3" diameter pipe is more than double that of a 2" round pipe..

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mv75
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Re: New GC8 99 Owner .... Mods

Postby mv75 » Tue May 09, 2017 3:37 am

Damn Deli, where were you when I was tuning this larger intake? Doesn't matter, I had a eureka moment on Sunday when I realised I had the math only half right for calculating the g/s maf scaler. I was calculating for a sectional rather than volumetric flow. doh. There was a lot of mis-information out there about tuning for larger intakes. I found one obscure reference to the actual right way. It was running ok, nothing dire, but after applying the correct math the car runs a lot better.

Ok, stock fuel system, I can't give a kw number, but rather info based on duty cycle. On my 2000 gc8 with vf34, stock injectors (yellow top side feed 440cc), were capping out in the 90%'s @ 18psi. It handled it fine. Stock pump. For my set up. But on my franken motor 257 in my gd with the same turbo, the standard injectors (blue top feed 420cc), were going over 100% duty cycle @ 18psi. Stock pump. I immediately bought some id1000's and swapped in the dw200 pump I had in the gc8 when I was running it on 1000cc side feeds for flex. :) Oh, and the flex sensor because you know, bigger injectors and pump, it's practically there. :)

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Re: New GC8 99 Owner .... Mods

Postby Androo26 » Mon May 15, 2017 4:23 pm

Ok Im back ... Ive done a 800km round trip in the Rexy down to Bathurst and back for the Nulon Nationals event. I went through the hunter Valley and down the Putty road , Bells Line ect in both directions. All I can say is sensational !!!

Right now here is the dyno sheet of the completed install and tune. Gained bang on 30kw @ the wheels. Before Tune 134.5 kw @ 13 psi
After Tune 164.5 kw @ 16 psi

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Androo26
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Re: New GC8 99 Owner .... Mods

Postby Androo26 » Tue May 23, 2017 7:20 pm

Driving the GC8 down to Bathurst and back i found that the brake pedal was not completely to my liking ( a bit too much pedal travel and a little spongy )

So over the weekend I bled the brakes and adjusted the sometimes forgotten brake pedal adjustment rod. Now I have a nice solid pedal that feels heaps better.

Can anyone with experience tell me if getting braided lines are worth the time and effort ?

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Re: New GC8 99 Owner .... Mods

Postby mv75 » Wed May 24, 2017 12:09 pm

It was fun to do and an excuse to fully bleed the whole system out, but worth it? Nah, brakes were the same. I'd only do it if the lines are already damaged or you're doing something fancy like hydraulic hand brake.

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Re: New GC8 99 Owner .... Mods

Postby abeiq » Thu May 25, 2017 4:58 pm

Androo26 wrote:Driving the GC8 down to Bathurst and back i found that the brake pedal was not completely to my liking ( a bit too much pedal travel and a little spongy )

So over the weekend I bled the brakes and adjusted the sometimes forgotten brake pedal adjustment rod. Now I have a nice solid pedal that feels heaps better.

Can anyone with experience tell me if getting braided lines are worth the time and effort ?


how did you go about the adjustment? im thinking about adjusting mine.

As said above, unless you're doing a full brake service, probably hold off. I have them on my GC8, but i did them when i did the 4 pots and new pads + rotors, made a good difference, but also did a full flush too at the same time.

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Re: New GC8 99 Owner .... Mods

Postby Androo26 » Fri May 26, 2017 3:12 pm

Here is a brief example pic... disregard the number measurement

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You want to be adjusting the lock nut and push rod..... Play around with it until you get a good pedal feel and the brakes are not dragging. note there needs to be some free-play in the pedal. Consult your Subaru Workshop manual for exacting measurements.

Androo26
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Re: New GC8 99 Owner .... Mods

Postby Androo26 » Tue May 30, 2017 11:30 pm

So now im making up a better solution to mounting the ECU and associated bits.

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Androo26
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Re: New GC8 99 Owner .... Mods

Postby Androo26 » Thu Jun 01, 2017 1:05 pm

Im in the process of making a custom made mounting plate to try to better arrange the Haltech and other bits.

Here is the start of it.

Image
Last edited by Androo26 on Tue Jun 06, 2017 12:36 pm, edited 1 time in total.

Androo26
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Re: New GC8 99 Owner .... Mods

Postby Androo26 » Tue Jun 06, 2017 10:49 am

Ive got a bit more done with the mount by making up these 50mm aluminum spacers. With M5 threads in each end.

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And they go in here, so the top can then bolt to it... protecting the parts underneath.

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The lid will have a couple of creases / bends in it to help make it stronger.

Androo26
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Re: New GC8 99 Owner .... Mods

Postby Androo26 » Tue Jun 06, 2017 12:35 pm

These have also turned up today. Shifter bushings. Mine is really sloppy

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Delivan
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Re: New GC8 99 Owner .... Mods

Postby Delivan » Tue Jun 06, 2017 11:18 pm

Nice.. I made a similar case out of heavy perspex for one of my daughters wrx ecu...It lives under a steel plate under the carpet so it is safe under there. I was previously just wrapped in bubble wrap...
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'09 Impreza Charcoal Hatch Auto
'03 WRX Pearl Red Bug Sedan
'02 WRX Silver Bug Wagon
'98 WRX Blue Club Spec Evo 2 with 2.5 lt
'99 WRX White Sti Version 6 with 2.5 lt
'98 Mitsubishi EVO 5 (kept in the basement)

mv75
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Re: New GC8 99 Owner .... Mods

Postby mv75 » Wed Jun 07, 2017 5:18 am

Nice dude. How are you going to mount the base plate? To the stock cover holes on the car?

Androo26
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Re: New GC8 99 Owner .... Mods

Postby Androo26 » Mon Jun 12, 2017 10:53 pm

Its a bit of a sheet fight in there with all the stuff but its much neater than what it was.

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I picked up this Hi-tech GD axle back 3" muffler section from a member on a Subaru face book page im on. I hate the way mine currently looks , so hopefully this one will be better.

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Androo26
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Re: New GC8 99 Owner .... Mods

Postby Androo26 » Tue Jun 13, 2017 12:12 pm

And here is what it looks like.

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Androo26
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Re: New GC8 99 Owner .... Mods

Postby Androo26 » Thu Jul 20, 2017 4:54 pm

Ive got a hole in my radiator and the smell of coolant and constant topping it up is pissing me off.... so this arvo I picked up this Mishimoto unit from Prospeed Racing , wich isnt to far from my work place.

Image

I shall install it in the morning.

ryano
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Re: New GC8 99 Owner .... Mods

Postby ryano » Fri Jul 21, 2017 12:30 pm

i had one of these and it leaked within 2 years so i ended up buying an OEM one as the original lasted 15 years or so, i still haven't got around to returning the mishimoto because its a bit of a pain so it just laying around at the moment

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