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as some of you may or may not know, i own a aus spec r31 with a rb25det and 5 speed.

its an excellent performing car for the mods it has, and the amount its cost me.

so far has

cooler with custom end tanks to negate the need for a pipe over the radiator

3 inch from turbo back exhaust

500hp fuel pump

it will be getting a clutch soon enough and an lsd.

from there ive always wanted to go bigger turbo and ecu.

However, once you begin modding cars you realise it isnt going to happen as quick as that-

so my question is, what other things can be done to improve performance without having to go ecu turbo. im thinking along the lines of porting manifolds etc, im not looking for massive gains, but anything would be an improvement. Gotta keep up with the jones's you know :cheers:

as a benchmark , it did a 15.0 @ 98mph , with 2.9 60 foot times, due to me not wanting to destroy the stock 31 clutch in the car, this was before any mods, ie no cooler or zorst, and a misfire under hard load.. which was found to be a coil. goes alot harder now , turning 2nd gear with a slipping clutch on acceleration. and beat a car that had ran 107mph 3 weeks ago.

I look forward to any suggestions that you may have, as im keen to see how far this thing can go before going to bigger and better things.

Tom

How about changing the diff ratio to something a bit lower, like 4.8:1? Aerodynamic mods too? But if you put a dollar to kw value on mods, you can't beat the "common" mods of turbo + ECU.. and pretty much any large engine changes you make is going to need an altered management system.

If your interested in doing head work you could clean up the ports a bit, and maybe port match the manifolds to the head etc. Then look into cams, but they are a bit pricey :cheers:

Also, if you doing yourclutch soon, look into a light weight flywheel, might as well do it while you've got the box out ;)

On that subject, could also look into reducing the rotational mass of things (like the fly wheel) like pullies. Maybe think about ditching the clutch fan for an electric one.

Don't forget that sometimes a good service can yeld good results too - change the oil in the gearbox and diff, good alighnment etc...

J

Also try a set of pineapples to help lower that 60ft time. $120 and easy to fit, and they do help, even with my launch unfriendly setup. Cheaper than new coilovers too.

only reason the 60 foots where shocking, was because i was driving of line like a set of traffic lights to save the clutch

flywheel was certainly going to be done at time of clutch

pullies and stuff like that was something i didnt think of though

maybe even a cold air induction setup, or partioning off the pod

brains starting to tick now :D

First thing.. Get your self a nice tight LSD with a ratio of 4.11:1 (R33) 4.36:1 (R33) & a decent clutch.

It will make a big difference to response and acceleration.

What kind of speeds are you getting out of your gears at 7000rpm?

You said cooler.. Is that a stock IC as per your sig?

Possibly a cheap SAFC ($250-300) + Tune $200.

You can always sell the SAFC later on down the track without much $$ loss.

Pick up a decent amount of fuel economy also, be sure to get it tuned for light and WOT throttle openings.

Some tuners may only tune for WOT thinking all you are interested in is a final power figure. An Extra 100km's to a tank of juice wont go a stray.

Your ET indicates there's definately potential providing you get those damn 60's down. :D

was a standard cooler, now is a custom garrett one, sig not updated due to no more power runs since that :D

diff at the moment is a freaking pintara 4.11 single legger

speeds at 7000rpm

1st = 60

2nd = 100

3rd ... over speed limit :D

really interested to see what someone like sydney kid thinks in regards to this. ive always like to think outside the sqaure. i could just do ecu manifold turbo and fuel and be done, but if i can do a 12 with stock turbo id be very impressed.

If you want to see 12's on the cheapish..

PowerFC

Injectors (Don't skimp on these or you will be rebuilding)

Z32 AFM

An internal gate 450-500hp turbo (GCG or Unique autosports type turbo)

You should have some where around 250rwkw.

If you want to push the turbo a little more and keep the response of the smaller turbo I would look at a set of mild cams, thicker headgasket and a little more boost. You may find your self hitting 270-280rwkw.

Then look towards the suspension setup and tyres.

12's on the stock turbo is pushing it + the turbos reliability will be limited.

Its a Silvia (1220kg's). Less weight = less power required to haul arse down the 1/4.

Unfortunately the R31 is one of the heavier skylines weighing in with a kerb weight of 1440kg's.

It 'could' be done but the turbo won't last long as you will have to lean on it hard.

Depends what you want? Reliability or a tow home after a night out.

To have the same power to weight as a S14 has at 200rwkwk you will need around 240rwkw.

With you get the clutch fixed, DEFINENTLY get a super light weight flywheel.

Awesome difference.

$500 from Japan (I got mine from www.JapaneseImportParts.com) and it's probably good for 0.4 over the quarter. (Reference Rev210)

BASS OUT

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