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What mods can be done with out tuning ECU?


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#1 Josh18

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Posted 25 January 2019 - 01:48 PM

As the title suggests, what mods can I do to my early gen2 LGT, twin wastegate model? I'm not planning much at this stage but it would be good to know what I can do ie exhaust, filter etc with out tuning the untuneable old ECU. I'd like to put a more free flowing better sounding exhaust eventually.

Cheers



#2 Barbbachello

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Posted 25 January 2019 - 02:48 PM

Can pretty much do whatever you want apart from change maf or injectors. The older ecus tolerate mods pretty damn well and you cant replace the twins with anything big enough to outflow everything else.

Mod away


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#3 Josh18

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Posted 25 January 2019 - 03:05 PM

That's good to know.

As far as by feel performance increase, If I put better downpipes, cats, exhaust on it and a better filter would much change? The stock downpipes in particular seem super weedy and restrictive. I have read that just freeing up the exhaust will increase boost levels on its own. I have also read that relocating the boost control solenoid to the engine bay and shortening the lines helps the performance of the primary. Has anyone tied this?

Lastly, how similar is a WRX exhaust to an LGT? I realize that I would need to modify it to make it fit the TT but I thought maybe a big exhaust from a wrecked rex might be a good place to start.

Cheers and thanks for the info.



#4 Barbbachello

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Posted 25 January 2019 - 06:05 PM

Exhaust is always a good upgrade on turbos. 

GC8 catback will fit with about 10cm extra added. 3" catback with 2.5" dumps is the way to go. Dumps youll either have to do custom or import some from japan


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#5 Josh18

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Posted 25 January 2019 - 08:17 PM

Thanks Bab, that's what I wanted to hear, sizes too. I'm ok to fab the down pipes. Mine has a cat in the down pipe and another in the primary down pipe- do I need to run both to keep the ECU happy? I was thinking just one high flow in the centre pipe.

Also since Ive had it the O2 sensor for the centre cat has been unplugged. It has one plugged in in the in the primary down pipe and another somewhere maybe the primary up pipe. I cant find a corresponding plug for that rear O2 sensor. It runs fine but does it need it? I have seen cars before where they place an O2 sensor before and after a cat foe emissions or something that does nothing for the running of the car- is this that sort of thing?

Another thing I noticed when changing my primary turbo is that the up pipe diameter is much larger than the inlet of the turbo and the junction is all right angles. I don't know why they would do this but it looks like a major flow restriction- can the turbo inlet be ported?

Cheers



#6 Ordex

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Posted 27 January 2019 - 07:35 PM

the rear sensor is a temp sensor to warn you not to park on grass when it's hot :)

there should be a lamp for it on the dash that turns on when you turn on the ignition. Mine's never turned on other than when starting the car.

I've read around the place it'll run fine without the temp sensor. No idea what it actually does apart from operate that lamp.



#7 Josh18

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Posted 27 January 2019 - 09:26 PM

Thanks Mate. Yeah mine has just been sitting there with nowhere to go since I got it, doesn't seem to bother it, that makes sense.



#8 Josh18

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Posted 09 August 2019 - 03:15 PM

Hey guys I finally got around to fitting that big exhaust. I have been wrecking a gc8 WRX and used the 3" system off that. I made up my own dump pipes in 2.5" and didn't bother with any cats. I have to say it goes great, with no ill effects noticed so far. It might use a bit more fuel though its hard to tell as it's hard not to drive it hard now! I need to set up an AFR gauge to see what the mixture is doing though I think. I also have a zerosports boost controller to fit to try and move the VOD up a bit but have to fin the time.


I just need to add a couple of flex joints to the dump pipes, which I picked up today, and sort a leak in the flange between the dumps and main system and its done!

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#9 Josh18

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Posted 11 August 2019 - 09:27 PM

I got around to fitting my Zero Sports boost controller. I was a little dubious as to what it might do given hearing about fault codes etc. First start went OK but once warmed up though the idle started surging and the car would die. Also I had no boost reading.

Driving it around it sort of worked but not too well. I unplugged wires until the idle surging stopped and found it to be the one labelled "pressure", boost maybe? I pretty much thought  oh well, too good to be true. I was going to rip it out but had one more look over the wiring, particularly the one causing the issues and lo and behold I found I had miscounted the pins and tapped into the wrong wire. So I fixed it and now it is just AWESOME! I set the change over to 4500 and its just great, no more stuck in VOD and the change over is now super quick as there is so much more gas to spool up the second turbo.

SO GOOD!



#10 duncanm

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Posted 12 August 2019 - 09:46 AM

Great to hear the ZS worked out so well.

#11 Josh18

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Posted 14 August 2019 - 01:07 AM

Now I have a boost guage through the ZS I have realizrd why the car is som uch faster after the new exhaust- it is boosting to 14 and 18 PSI on single and twins! Im frankly a little worried about how long it wil last. But the other half just loves the rush when those twins kick in!



#12 Beckers

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Posted 14 August 2019 - 11:19 PM

That boost is about right, I get 11 psi on primary and 19 psi on the secondary.



#13 Josh18

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Posted 17 August 2019 - 08:57 PM

How has it been long term at that level?

Cheers



#14 KONG

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Posted 18 August 2019 - 11:30 PM

What turbos do you have?
Nice fab work by the way

#15 Josh18

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Posted 21 August 2019 - 01:34 PM

Hey, VF 13 and 14 with grey injectors and a four plug ECU. Was originally an auto. Its a BG5A.

I welded in some flex joints to the down pipes on the weekend and sealed a leak at the flange between the downpipes and the main system. It fits much better and that leak is gone but I'm pretty sire there is another leak there somewhere- makes a strange sound under acceleration, like a "ticking". I think it started about a week after the initial install. I think because I had no flex joints originally i may have cracked the up pipe or something. Its only quiet but annoying. I need to jack it back up and check it out.

Cheers



#16 Beckers

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Posted 21 August 2019 - 05:43 PM

How has it been long term at that level?

Cheers

2 years.

Kong was pushing 20 psi on both turbos, when he had white kong.



#17 KONG

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Posted 24 August 2019 - 08:36 AM

Good luck with the exhaust leak, I hope it's something simple. I had VF33/32 @20psi and never really had any issues with the turbos for the most part. The primary started to make a little more spool noise towards the end of the cars life but it had run for over 300k km so that's to be expected.
Not sure on the capabilities of the VF13/14 myself. 18psi is decent ... enjoy.

#18 Josh18

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Posted Yesterday, 07:08 PM

Thanks guys.






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