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After market ECU on a GTS25?


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hiya all,

I have a R33 series1 GTS25 sedan which I have been slowly been working on over the last couple of years.

so far things that have been done,

K & N panel air filter


2 1/2" exhaust

manual conversion

nasty heavy duty clutch plate (you can't slip this one)

Installed a LSD

Front strut brace

king springs

bilstein shocks

white line rear sway bar

nolathane sway bar bushes

ROH adrenalin alloys (shadow chrome)

Mintex road/race brake pads

GTR rear spoiler, side skirts and end caps

I have a 400R front spoiler too, which I haven't had painted yet.

So the time has come and I have the erge to spend some more money on my baby. I have looked into many different options to try and and gain a few extra kw. I thought after market cams, a fuel pressure regulator and a safc would be the way to go, but found that the standard ecu would be the limiting factor in trying to get any decent sort of gains from the cams, and giving my stock cams a mild regrind wouldn't really yeild any noticable power gains.

So this got me thinking what if I spent my money on a new after market ecu, and use it as a base to work on in the future. After much thought this is the way I have decided to go, so I have ordered a new ecu (R33 GTS Link) which I should arrive in mid January, and hopefully will go into the car in late febuary.

So have any of you guys/gals replaced the ECU in your N/A skyline?

If you have, did it make much difference?

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What about a unichip? i've heard they do good things for a turbo, what should i look for with a unichip or some sort of piggy back to get some gains..?

Can anyone speak from experience, or recommend any sorts of ecu systems that'll help??

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Not to sure how rich the mixtures are on the NA RB25's.

If they are quite rich like most Nissans chances are you should be able to lean them out a bit and pick up some good mid to top end power.

I would imagine the factory timing would already be quite agressive if they were mapped to Jap spec fuel, so probally won't be able to add much more in that area than the factory ecu already has.

You should be able to pick up a little bit here and there though...

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Do they require tunes and stuff done to them?? is there anyway i can buy one off someone thats just plug in and go?? how much of a gain can i see??

As far as I know they need to be tuned for the individual car, to get the best out of them. The ECU I'm getting is a plug in sort and will be set up first using a laptop and then fine tuned on the dyno. The guys selling the ECU to me, said that I should gain around 6-10kw with the addition of a tuned ECU on the dyno.

The ECU I'm buying gives me the option of removing the AFM, do you think this would be a good idea? Any one had any experince with a car with the AFM removed?

Yeah I think RB30-power is right in saying the A/F mixtures are rich, I have a A/F ratio gauge installed and it's always reads towards the richer end of the scale.

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I've seen good results from ECU's on the RX8's from leaning fuel and advancing timing, this was in the US on some low-octane fuel too.

I can't see why an improvement couldn't be had on the RB25DE as well.

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hey guys just some feedback and notes that ive read on the forced induction area

skylines are best suited for closed loop operation and using an air flow meter

theres jack all restriction from the air flow meter and removing it will give you nothing

you can inherit some bullshit problems and bad fuel economy from doing so (removing afm) as you usually use a map sensor instead im pretty sure.

also the cost to fit and tune an aftermarket ecu is a lot compared to gains achieved?

$1100 for power fc, $300 for tune and you get what 10kw extra?

most gtsts with power fc fitted and a shitty $100 bleed valve suck out an extra 30rwkw from ecu and tune much more resonable gains

have you guys considered turbo conversion instead of making the n/a faster

merli covered it once before and it does seem the most "cost effective" approach

just my 2 cents

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you know the probably cheapest and best outcome

drive r33 gts25 n/a for 2-3 years or whatever once you are ready and have some cash

do an rb30 bottom end conversion and use a turbo manifold

cheap base car that hasn't been caned

rock solid rb30 bottom end

turbo head with new turbo, ecu, injectors etc

should be a real killer and make massive power

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A bit of a gain can be made with the addition of an aftermarket computer with the added bonus of it running cleaner and more efficient. Keep in mind though a heavily modified N/A GTS will still struggle to keep up with even a lightly modified GTSt.

My advice, save the cash and do an RB25DET engine conversion. While more expensive in the short term, it will be far cheaper to extract more power out of it down the road. I did it on my R34 and have not looked back!!

My 2 cents.

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Sounds like a plan, anyways, my skyline does me just fine as it is right now anyways... only my first car so i cant really complain... i dont wana have it for ages anyway, at the end of the day, i wana upgrade to an R34 either late 05 or early 06 when i have some driving under my belt, but even still... i want it to be a non turbo for the time being!

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I'm fully aware that a lightly modded turbo will out perform a modded N/A. I'm lucky enough to own 2 skylines one a lightly modded turbo R32 GTS-T and the other is my R33 N/A, and yes in a straight line the GTS-T is quicker although at top end the GTS25 holds it's own and there's nothing in it and will slowly pull away from the R32. The truth of he matter is that I perfer the N/A over the turbo, and it's different, not many people choose to work a N/A, and I'm curious to see what sort of results I will be able to get, even though I know it's going to be expensive, and have relatively small gains for the amount of money spent.

As I said in one of my earlier posts I'm buying the ecu as a base to work on for future mods.

I have looked into doing a RB30 bottom end but have decided against it, and stay with the lighter RB25, and see what i can get out of it, One of my friends has put a RB30 bottom end into his car and last dyno he got 130rwkw and over 600Nm of tourque with extractors, pod filter, a 3" exhust system, and mine is currently at 112rwkw and 475Nm of torque.

Thanks for the advice on the AFM I have since done a search and found some info on the subject, and will most definitely keep the AFM.

When the Link ECU goes in I'll post up the results if people are interested.



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