My Engine specs...please help!

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Nov 8, 2005 | 09:58 PM

#81

ian sibbert

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From: Lancaster, Lancs

Quote:

Originally Posted by Hooligan

Right, I had a Nissan Sunny GTI-R for about a month some 2 years ago...
It was supposed to be a group N rallycar but I guess with a proper group A shell, big AP brakes, Proflex group A suspension and a very illegal engine it was what we call a mini-group A car...
The engine was a full group a engine with silly cams, God knows what compression and a restrictor on the turbo.
It would FUCK OFF at an alarming rate untill you hit 5-5500 rpm and it's like hitting a brick wall

The way it catapults out of corners from on 2000 rpm defies belief but you are forever changing gears...I used to love hammering it around town wich is fun as you have loads and loads of corners and jumps (some people refer to them as speedbumps) but it's thirst, constant need for fettling (the cams or followers needed some specific maintenance, can't remember) and the lack of top end killed it for me. On the motorway you'd be in top and topspeed in a second and next thing you know is you're droning away whilst every mondeo passes you...
Oh, and it broke several gearboxes and diffs, had a whole case full of them in the garage wich were destroyed by the previous owner!

So I would advise against it and recommend a nice 400-400 engine with shorter final drive for more resonsive feel (less laggy) and proper accelleration!

Oh dear...a sensible response to a post by Phil from me...what is the world coming to???

Just ask anyone that has a Subuaru RA or a Mitsi RS...all made for the Grp'n' rally market low geared and lightening off the line....as for the the standard front diff...the strengthening plate was a recognised grp'n' modification it stops expansion..... the major element you're fighting against is heat....ive seen standard diffs with additional oil capacity to aid heat control....the thick wall is usually combined in rally cars with the strengthening plate....all done to prevent expansion and diff failure....the gearbox and diff we run have built in oil pumps to enanble oil cooling.....if I were looking at improving the performance of any diff/gearbox the removal of heat would be something i'd look at early on.....size is important but when you look at the Japanese cousins they manage to transmit large amounts of power through quite small diffs...

Nov 8, 2005 | 10:01 PM

#82

Martin-Hadland

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From: Birmingham

Quote:

Originally Posted by pee vee

lol.
so what are these DOHC diffs good for then?

would the rear one be any good if it was coupled with the
transfer box mods?

martin-reyland aimed at you mainly lol

yes that would be ok but in an ideal world you would use the rear 3.9cwp in an uprated diff. as far as i can remember when fitting the chain and smaller diameter gears in the transfer box you will have a bit of grinding to do as the chain catches some raised area's of the alloy casing, not a big deal but worth mentioning all the same. you can have your existing chain shortened if it's in good order.

Nov 8, 2005 | 10:03 PM

#83

RichardPON

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If you run a small diff cooler, I presume it wouldn't require any kind of pump, and that the oil would circulate through the motion of the diff?

Nov 8, 2005 | 10:04 PM

#84

pee vee

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From: Wiltshire, Bath, chippenham area!

Quote:

Originally Posted by martin-reyland

thanks a lot.

learning all the time!
sounds like a mod i'd like for my car, to make it suit my taste a bit
better!

Nov 8, 2005 | 10:05 PM

#85

Martin-Hadland

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From: Birmingham

Quote:

Originally Posted by RichardPON

If you run a small diff cooler, I presume it wouldn't require any kind of pump, and that the oil would circulate through the motion of the diff?

you are going to have to pump it unless it has an internal pump ... i reckon you should really switch the pump via a temp switch, this will be on my new car

Nov 8, 2005 | 10:10 PM

#86

Anonymous

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Pump it sir....ohhhh i love pumping do you sir? ohhhh I seen you and Rainbird pumping it all over the net sir ohhhhh suits you sir ohhhh

Nov 8, 2005 | 10:13 PM

#87

Martin-Hadland

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From: Birmingham

Quote:

Originally Posted by Bosch-Man

Pump it sir....ohhhh i love pumping do you sir? ohhhh I seen you and Rainbird pumping it all over the net sir ohhhhh suits you sir ohhhh

very original bit of humour there

............. not

Nov 8, 2005 | 10:16 PM

#88

RichardPON

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Stop dribbling Phil

Cheers Martin, just curious

Nov 9, 2005 | 07:36 AM

#89

ian sibbert

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From: Lancaster, Lancs

I have the part no for the diff temp switch if anyone needs it......

Nov 9, 2005 | 11:30 AM

#90

PAUL S

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From: sunny wales

Quote:

Originally Posted by martin-reyland

Quote:

Originally Posted by a.k.a

Quote:

Originally Posted by martin-reyland

Quote:

Originally Posted by a.k.a

An alternative to changing the step offs in the box is to use the front 3.9 diff from a 2 litre DOHC 4x4

As long as you match the diffs front and rear you dont need to touch the box

People say its not a strong front diff but then again neither is the 3.6 cosworth version

the 3.9 front diff is known for being very weak hence the use of the standard ratio front diff and step off gears

yes I agree for high power/heavy footed applications, but for people using standard 4x4 boxes they are a cheap and readily available alternative - I know of quite a few people running both front and rear sets of 3.9 diffs from the 2 litre dohc in 4x4 cosworths with moderate power increases who have had no problem with them, and if they do go they are easy and cheap to replace.

edited

meant to also say a lot of the problems are caused when people do not use the 2 proper extra mounting brackets that only came with the cosworth front diff when they use the 3.9 front diff which then allows the casing to flex and crack

first you say that you agree that its not suitable for high power cars and then you mention that you know a few people with moderate power increases using them... were we talking about moderate power increases? nope.

Its called being helpful, based on first hand experience on this matter

A lot of people read these threads and many of them pick up advice related to the topic even if there own vehicles may not be to the same spec - not everyone has a bottomless pit budget and some may have wanted to go the 3.9 route without having to spend big bucks, as they dont have big hp engines which need the stronger set ups.