rallyman2007

Some of you might know that the orginal Impreza, the GC8runs out of homologation at the end of the 2008, and for those of you who don't know what homologation is, it's the accepted form of recognition from the FIA that allows a car to compete in all forms of international motorsports.

The GC8 was homologated in Group A (which allows serious modifications) and Group N (which means that the car must run almost as built by the manufacturer) and it was with the Group A version that Colin McRae first won the World Championship and which was probably Subarus most succesful ever rally car.

The thing is that homologation only lasts for a certain period of years and the homologation on the GC8 officially runs out at the end of this year. This means that the last WRC event that the car can compete in will be the Wales Rally GB in November, and I've got it into my head as part of a long term TV and DVD project to build up a GC8 Group N car over the next few months, with the specific intention of competing on Rally GB.

I have competed on the event 3 times before but never in a 4WD car so it's something special for me, although in real terms the car won't be competitive as over the past 8 years or so things have moved on in terms of Group N performance.

Because I am new to Subarus' I hope that some of you will encourage, advise and abuse me throughout the build. Indeed when I first posted on Scoobynet, it was one of the moderators who invited me to write this thread and I have already received a bit of advice and bought several bits and pieces off other Scoobynet members.

So to the car - or cars! I originally bought a shell of ebay, this was a 1999 shell with the registration S55 ACC. I actually bought it as much for the number plate as anything for reasons that I explained in my original scoobynet posting but which got me into trouble immediately for advertising my business, but we all live and learn don't we?

That shell was immediately delivered to Custom Cages in Daventry who have welded in a proper Group N cage, and what a cage it is! Hopefully I won't be testing it to destruction but you can see from the pics how substantial it is.









What you can also see from the pics though is that the car still has the sound deadening panels and my first decision is whether to spend weeks easing those panels out with a blower and a scraper, or whether to go the simpler but far more expensive route of getting it dipped and then repainted - Dipping will of course clear all the underseal as well, but will also clear out a fair chunk from our bank account before we've even started, with various loose estimates of about £1000 just to paint the shell again.

Anyway after I've done that we will rebuild the car with bits from a damaged STi RA that I bought via Scoobynet. IT runs ok but the shell was buggered. In fact I bought two cars (one of which was just a rolling shell) and immediately put the spare shell, the wheels and the seats for sale on ebay. It's always my intention to recover as much money as I can and to buy and sell bits and pieces via Ebay and Scoobynet, so please keep your eyes open for my sales and wants!

This is the 'donor car'







That's enough of an intro for now I think and of course before when I mentioned a DVD project, I'm hoping that you will be able to buy the DVD via Scoobynet as and when we get the project finished.

911

Great project!

Rule to new 'Projectionists:' We need a lot of pics or you will get some grief
Nice cage with a few tubes I've not seen before in other cages.

Seen an ad for a blasting an Impreza shell for £550 to bare steel. £1000 for a repaint sounds good to me.

Look forward to the regular picture strune reports!
Graham.

rallyman2007

Thanks for that - it seems that I have to learn how to load my pics properly - wonder where I went wrong, (could they just be too big?) and you're right about the cage, Roger Nevitt at Custom Cages did say that there was one or two new ideas in there!

ukbob

hi david,
first off good luck with your project,are you doing all the work yourself?i see from the pics there are no seat bars..surely cc should have fitted them.there is a lot of weight to come out off the shell,and some reinforcing of mounting points to be done.as a guide my gc8 shell weighed 270kgs painted ready for build.if you are in the oxfordshire area you are welcome to come and scout around my car for tips/ideas.i will try to speak to you at the autosport show.ttfn neal

rallyman2007

Already more feedback than I expected in the first evening. Very interested to see how much weight we can lose. I have been talking to the chap who won the BTRDA Clubmans Production Cup in an almost standard STi RA, a fella called Alex Allingham and he said that a scrutineer said that his car was a 'fat old thing' when they weighed it, so obviously there are tricks!

The pictures are here for now, while I try and get things sorted

Picasa Web Albums - David - Subarushell

Picasa Web Albums - David - Subaru

And Neal, yes, we'll be at the show from Thursday, stand K605

rallyman2007

Well here are the pictures at last.










And of the donor car.





I've done enough research of the past few months to know that this is the closed block engine so it should be good and strong. The question is whether to go for a dog box or stick with the original. And I know that they are supposed to be weak, but several people have suggested that if you treat them with tender loving care, they will do the job for you.

I'll post again after the weekend, when no doubt having spoken to many people at the Autosports Show a few more decisions will have been made - all of them costing me money no doubt!

rallyman2007

I've deleted this because it was a duplicate post

911

The box will be fine I would say from experience with my hillclimb car (much the same as a very short tarmac stage...)

370 bhp/360 lbft through a stock Sti V3 non dccd box and then a Type R dccd box with AP organic and full hillclimb sticky slicks.
4 years on and all is well. (about 250 x 6000 rpm and dump the clutch hard starts)

You have lots of credit card scares to come yet.

UKbob is right about the seat rails; they are the only way to sit low in the car. My seat is 50mm lower than stock and feels great, but would like to be lower still.

Suspension and brakes?

sanf

Hi David,

Good luck with the project. We bought a 2 door GC8 in October, and are just weighing up trying to get the budget for Wales rally GB for the very reason you have said!

Regards the gearbox ours had a dog box which broke on its first event! For a replacement we are looking at around £3000 which seems a fairly common kind of price. TEG sport have a used P Bourne kit available for a GC8. PPG also seem a reasonable option. The main issue with Dog boxes seems to be the on-going cost. The dog rings are the bits that seem to get damaged, and depending on driving style this can happen quite quickly, with each ring being about £120!
The standard boxes from what I gather aren't too bad, the gears are strong, but on the version 3/4 the gearbox casing tends to flex which can cause problems, and the shafts are the weak points. If you have a version 3/4 when you get the box sorted make sure you get it built into the version 5 (54) box as it's stronger. I think we are now going to switch and run on a syncro box as ours is grp N.
Some useful contacts are Dave at API Engines who is looking at our box now, and also Gwaine at Langworth Motorsport is involved in running about 4 Impreza's and knows pretty much everything about them!
Good luck, I'll let you know how we get on with our gearbox hunting!

Denn

Jolly Green Monster

iTrader: (4)

very nice..

the sound deadening comes off when cold with a hammer and chisel etc..

Simon

rallycol

iTrader: (4)

You can buy my complete rally car top spec GPN and go the pub and relax

j-k

Good luck with your project...lots of patience required..

We have a Group A impreza in tarmac spec thats a self build...

As simon says above, cold chisel and a hammer to get off the sound proofing..DONT HEAT IT UP, it becomes a nightmare to remove.

View my scooby...
<<<<<<<<<<<<<<<

jon

ZEN Performance

A standard box will get hammered. A standard well built engine should be fine though.

A broad woodchisel with a slightly dulled edge and rounded corners is best for chipping off the sound deadening, which is best done cold.

Paul

rallyman2007

A bit like revenge eh?

Off to the show now will get time to check the replies fuller and add more early next week.

stoneface

iTrader: (6)

ukbob

hi david,hope you had a good autosport show.my mind has been buzzing with all the info to talk to you about/show you.i had to write it all down in the end before my head exploded!!!speak to you soon regards neal

rallyman2007

Thanks again for all the replies so far. It does seem, and as UKBOB said to me at the weekend, that this is a very interesting project but a bit of a minefield!

So what news?

I'm pleased to say that I have been able to strike a deal with AVO for a set of gravel springs and dampers and they will fit them and set up the car for me at their workshops, which is all good for the filming. That's really helpful because I had an MG ZR with their dampers on and we set it too high with the result that we preloaded the front springs to about 600 lbs which didn't help the handling very much. After I'd complained and they responded by setting it all up at the factory I realised that we were wrong and the car handled fantastically well. I'm happy to use their dampers on that basis alone as much as anything else because as we all know back up and service are all important.

I'm also really pleased to have spoken to Neil and Dan from Adrenaline Motorsport, who make the Subaru basedd Murtaya Sports Car. Our original shell came from Adrenaline and they have said that if we use a SimTek ECU and take the car down to them, then they will set it up for us on their rolling road, which again is also good from the filming point of view and they offered to help which is a bit of a bonus as I was unsure what to usem although I did favour the GEMS kit but only because so many other people use them. Dan said, and from reading through this forum, it seems that others agree, that the SimTek ECU offers several advantages, especially on cold starting, but the most important thing to me, yet again, is the back up service.

As for the shell. One minute I'm all for dipping and re-painting, the next I'm just going to get the chisel out! On the one hand I want the best car I can build, but on the other I want to build the cheapest I can, without building a scrapper, and not dipping and painting will save me about £1500 without compromisng performance that much considering that this will be my first 4wd turbo car! I do expect it to be quicker than me for the first year as least!

It's also interesting to see that several people on this forum recommend doing the chiselling cold, where elsewhere I've seen people recommending doing it hot!

Does anyone know what the actual weight of the underseal and sound deadening is? I think it's about 25kgs or thereabouts isn't it?

In addition to that UKBOB also suggested several areas where the shell can be lightened and several areas where it can be strengthened. He also mentioned a Prodrive Group N build manual. Could anyone lend me one please? I'll happily pay postage and send you a couple of DVD's if you're interested although I guess that I can't point you to our web-site in case I upset the mods. Can anybody advise me on that?

And I will of course get seat bars fitted. I think that that was just a simple mis-understanding between Custom Cages and I.

Earlier on in the thread I was asked about the brakes. I need to read the homologation papers properly on this one because I know that you can fit the bigger four pot Subaru discs and calipers, but what I don't know (because of a lack of Impreza knowledge) is whether these are the AP calipers because someone said at the weekend that I could fit the AP calipers. Again you only have to look at the homologation papers to see what a mine field it is, even in Group N - and it's even worse in Group A with hundreds and hundreds of pages and regular updates. In fact I was talking to one scrutineer before I started and he said that it was virtually impossible to police these cars properly because Prodrive were always homologating new parts and they couldn't keep up.

Interestingly, that brings me on to the gearbox. I didn't realise that the dog box was homologated for the GC8 because I thought that the gearbox had to remain standard in the earlier cars, but I'm happy to be proved wrong there. UKBOB did tell me though that if using the standard box to check if mine is the 754 which is strong enough as opposed to the 752 which isn't.

I was also told to think about updating the turbo - any thoughts there please?

Hopefully work will start this week on either chiselling or dipping!

By the way, does anyone know if these will fit my car? I know an Ohlins technician and he might be able to rebuild them as tarmac units for me.

Subaru Impreza STI/WRX Ohlins Eibach suspension on eBay, also, Subaru, Car Parts, Cars, Parts Vehicles (end time 18-Jan-08 11:32:19 GMT)

John Stevenson

As Paul points out, only, I use a Gasket Scraper, ideal for the sound deadening. On a cold day in hell you can do it all in a day, did so just the other week.

---john---

ZEN Performance

a standard UK 754 box will not be strong enough if it's a UK box, nor will it have homologated ratios, although that may or may not be an issue. An early RA box, or even better an S2 prodrive group N box might be on the used market for not too much money.

rallycol

iTrader: (4)

If this is a big IF,I still have a load of GC8 rally parts lying around,before you do the rally, you can borrow them as spares to do the rally ,on a sale or return basis ,this includes suspension wheels diffs dogbox etc ,this is a genuine offer as I've done it before,and if you need a service crew, and if I'm not already commited ,myself and a good mate ( who is also a very experienced rally mechanic) will help you out on the event for beer vouchers PM me if you want

sanf

Hi David,

I'm not an expert like many people on this site but since getting my Impreza in September have done lots of checking and am still learning. One of the big areas of conflict does seem to be the gearbox, and basically it's down to cost.

From what I gather the 752/754 are the gearbox casings. 752 were on earlier versions up to V4. The problem is they are slighly weak and tend to flex thus can cause the gears to seperate (nby tiny amounts). Subaru improved this with the V5/6 box the 754 casing which is stronger and flexes less.

Then you get what's in the box. Grp N Impreza's can run a dog box, but it is fairly expensive. Also you can't mess with the ratio's outside of the RA/STi/P1 standard ratio's which do differ. I gather the early RA's have far lower gearing.

Our car had the 752 casing on it from a version 3/4. It had a dog box but it's bust. So we are now going to put a 754 box on and see what happens. From speaking with cars previous owner they used to strip the gearbox every event and still had probems with it. To get a like for like replacement we were looking at around £3700, for the syncro road box it's around £1500 for a re-built one.
We are going to put a V6 box from a P1 with a shortened 5th in and see how we go. Could be a disaster!
We are out on the Wyedean and then hopefully the North Humberside so if you want a chat feel free to come and have a look, I'll et you know how we get on with the box and if we do destroy it! I know of at least 2 other gravel cars that run syncro boxes and seem to get them to last 4-5 events before re-buliding them.
On the brakes he discs should be 295mm front and 265mm rear. The front calibers can be 4 pot, so I presume any make is ok providing they don't exceed the size in the homolgation papers. I think Brembo made the Subaru ones, but I could be totally wrong about that.

ZEN Performance

I have run dog boxes in 752 cases and never broken a tooth. As far as I'm concerned the flex issue is an myth. A poor gearset will break no matter what case you put it in. Many improvements came with the 754 style boxes, but I've yet to find any proof that a 754 case makes an sti box any more reliable than a v3/4 752 box. I have customers with reliable boxes of both types, involved in motorsport, and there is no correlation between the failures or reliable boxes *that we have seen*.

If talking about a UK box from a classis, then forget it, they are doomed to fail 754 or 752.

Neil..

iTrader: (35)

If I were doing another bare shell rebuild, I would get all metalwork done (roll cage bracing etc...) and then get the shell acid dip stripped, and e-coated at the same time...

rallyman2007

Looking at the shell again this morning I am more and more tempted to go down this route.

One thing that I didn't mention and that nobody has noticed, which is quite surprising given how sharp people's eyes are on here, is that the shell is actually left hand drive so I have got a bit of work to do before I even start the build, but my head can't decide about the dipping or scraping. It was the first thing on my mind when I woke up this morning.

Can anyone tell me the easiest way to see the number on the gearbox please, do I have to get it off the car to see it?

911

The long code number is on a label just by the starter motor, obviously starts TY 752 etc
Graham.

rallyman2007

Thanks for that 911. Here's another question that's taxing me if you can help? I think I asked UKBOB this question at the weekend but got confused by the answer!

I have the STi RA donor car with DCCD. I believe that this all comes with LSDs' front and rear. I have also bought separately a 1.5 plate diff for the front. Can I just fit this to the front, replacing what's there, with no major problems, will it upset the DCCD, or even stop it working altogether or am I better of sticking with the DCCD set up and LSD's as they are? Also what ratio is the rear as standard, and is it a plate diff? And of that matter what is the centre diff?

Don't forget that I'm new to these Subarus' so this might seem a stupid question to those who know a lot about them, so please bear with my stupidity!

I think that I will definately just use the 'standard' gearbox. I've only broken one gearbox in my life, that's despite competing on events like the London to Sydney Marathon, so I think that I'm fairly sympathetic, but as mentioned earlier, it's important to rebuild these quite regularly.

I wonder if one would get all the way around Rally GB though?

ZEN Performance

You should be okay to start with the current box. if you can't stretch to a seriously upgraded box, have available (ie borrow) a box you can swap in if required.

ukbob

DONT DIP THE SHELL,if you intend to keep the car for a few years.if not cleaned out properly after dipping they will rot from the inside out,micro wave style!my underseal came off really easy with a hot air gun and scapper,then i had those areas blasted,then the only paint you need to do would be interior and underneath.email me your adress and i will send you the shell bulid manual.as i said before pop in and have a look at my car,everything will be alot easier to show you.You told me your budget for the car,i know you will be getting deals etc,but can you include the cost that everyday bods would have to pay as some of us are no good at getting deals .As for dog box,get the car build/driven first,they will blow a big hole in youe budget.you need to be on 4.4 to 1 ratios to help keep the box together with good acceleration.you wont need a year to get used to the car!

911

On the gearboxes:

My Type R box (TY 754 etc) came without a front LSD. Most boxes are open, lsd's were oprions.

I had a lightly set plated diff added by API, and a tightly set plated R160 in the rear, all 4:444 and with the stock dccd controller.

On road and hillclimbs i really disliked the characteristics of the plated front diff and API removed it for me (now sold to a rally guy!)

This was on a hillclimb track, could be a different matter on gravel.

Setting the dccd correctly for a given track is a very fine affair, the dccd is sensitive to where you set it and the behaviour of the car.
I removed the ABS from my Sti V3 because of the dccd.

As I said earlier, go with the stock box you have. They are easy to find, but Zen are experts on uprated boxes, and if you pop a stock RA/STI/Type R box I would dig deep and buy a ppg with billet selectors. About £3K ish.

I have only read that the TEG Modena box is strongest, but i believe this is much down to the driver, his budget and how raw he is.

You are obviously kind on boxes (as I am) so use good oil (I think you need to be careful what you use if you fit a plated diff in front) that will give the box a fighting chance. You could be pleasently surprised.

I am not sure the 752/754 Jap boxes are as fragile as some think.

Graham.

riiidaa

iTrader: (2)

Mad thread, a joy to plod thru. Best of luck, maybe I'll come cheer you on at Wales Rally-GB