One for the boostie-boys

[Fen]

Lets say you had the following (hypothetically):

944 (250bhp) turbo engine in a million pieces, needs bearings, rings, gaskets, clutch and not much else to be complete (OK, a sump as well [8D])
The head and turbo have just been rebuilt so are effectively new, but standard.
You also have:
an Autothority MAF kit
TiAL wastegate (35mm IIRC)
full Hayward & Scott exhaust system
ECU map to suit the above running 1.01 bar boost (producing something over 300bhp)

Intended use of the car is purely as a toy for trackdays and mad Sunday runs. Making it a pig to drive in traffic is not an aim, but may be an acceptable side effect.

If you set your mind to it you can throw £300 - £500 a month at it and you want to build the best you can. You also want to be able to do some trackdays in it next year so ideally you want it to go together for a couple of grand in a way that you can improve over time without any major dismantling or having to do the same job twice (remapping excepted).

What would be on your shopping list, both during the inital build and then on the improvements list over time?

To get the ball rolling I'm thinking:
Stick with the 2.5 capacity
Work the crank (lighten?, crossdrill, knife-edge? suggestions?)
Balance the internals?
Rebuild with Raceware fasteners top and bottom
Use a Huntley Racing 'Full Metal Jacket with O-Rings' head gasket
Lighten the flywheel and use a Cup spec?, sintered?, other? clutch
Is it worth doing anything with the head?
Have I missed anything - given that I eventually want to see the 300bhp increase dramatically, based on this core engine?

Would it be worth starting out with a 3 litre block and crank and a 2.7 head, accepting 2-3 months longer in the build but ultimately having the, erm, ultimate spec?

What would you guys do?

 

[Diver944]

Well Fen........how much do you want to spend [8D]

Seriously it's my opinion that you first need to get the thing back on the road. I think that as you only had the last power increase a short time before the 'sump incident' occured [] that you should put it back together as a 2.5

As long as the crank, rods and piston are still sound and its just the bearings and gaskets that need replacing to finish the job. If the crank were damaged or the pistons then thats the time to go for the 2.8 mahle stroker kit.

I would definitley go with the proper balancing, lightening and knife edging of the internals usng someone like Bob Watson who did your original work, or maybe tap into Patrick on Titanic who had good results with EMC engines doing the same balancing etc to his N/A 2.5 Lux and yielded 190 bhp from an original 163

If you need a clutch now then get an uprated one as you do plan to go further in future [] However if it were me personally I would sink funds into getting on as many track days as you can now and have fun with that circa 300bhp.

A well driven 944T on proper track tyres will still embarress many expensive supercars even with the stock 250bhp

.....oh, and get a titanium spaceage sump and avoid foxes []

 

[944Turbo]

I think an injector upgrade will allow more boost to be run without the risking of running lean.
I have heard it recommended not to go too mad on head gasket / head clamping down, as it is better to blow the head gasket than hole a piston should something go wrong.
Balancing and lighter flywheel should give freer revving.

As Paul suggests, I wouldn't spend too much on chasing major power - save some money for a set of spare wheels and slicks and do more days.
If biased towards track work I would be tempted to reduce the weight by removing the rear seat and some sound proofing, and fit a strut brace and possibly a rear cage. I would consider losing the stereo (or some of it anyway) and lightweight seats.

IMHO For really big power you can spend lots of money and would need to replace the turbo / intercooler, head work, electronic boost controller etc. etc.
and then the gearbox would probably need a rebuild (plus torque tube), big reds would be nice, etc. etc.

Tony

 

[Fen]

Yep, I think the 2.5 is the way to go, I just don't want to regret not going 3.0 later on (or 2.8, but that's been done before [])

How much to spend is a fair question. Realistically a couple of grand is all I'll have available between now and early summer (I DO need a clutch already). Unless I sell the cab and put the money into the Turbo, but I really don't feel comfortable with that plan. I intend to sell the Golf when the Turbo is together, which should raise enough for a set of road wheels and some slicks for the D90's I have.

I guess I want to build a good core engine with all the right stuff done so it doesn't have to come out and the head doesn't have to come of for some time. I can then do a summer of trackdays in the same tune as last time it ran, then I can throw next years bonus and some spare cash at it next winter and do the injectors, turbo, intercooler etc. What I don't want to do is miss something in the core build that I will later regret.

On the lightening side etc. expect to see some linen leather front seats and rear bench for sale pretty soon. I think I'm going to strip it out a bit but I will keep the air-con and the stereo is just a single box anyhow. It'll need big reds if it has much more power in the future, but I think the standard brakes are OK for now (we'll see on the track).

Things like injectors etc. I expect to have to add, but they can be in phase 2 since they just bolt on.

Cheers for the responses anyhow - anything you've gleaned (from Rennlist?) over the years is much appreciated.

 

[John Sims]

Not saying this is the right route, but an alternative point of view.

Noting that any hard driven and highly modified engine can be lunched no mater how good the internals (I destroyed a brand new blue printed race engine on its first outing) why not assume the base engine is going to die again at some time and just spend the money on bolt on enhancements which will still be reusable no matter how many base engines go pop.

Based on this, I would look at big intercoolers, bigger turbos, injectors, MAF, full metering and programmable managment.

Big intercoolers are good either way, by reducing the charge temperature you should get a longer life from the engine any way.

Assuming you can put up with a Spartan existance, weight saving is a double plus as it improves both performance and handling. Can I put down a marker on first refusal on your interior?

Having done the racing car bit, and noting the 99% of the time the Turbot is used on the road, I prefer comfort and opulance over the extra .5 of a second advantage []

 

[944Turbo]

Trackdays are not racing after all- but then more power is still very nice [] until you come to insure it.
At the end of the day if you really want a 3 litre you won't be happy until it's in and its cheaper to put it in now than later.

ref the stereo If you have the 10 speaker option you could remove some speakers to save a few kilos - I was feeling guilty about mine, could lose them all and put in 1pair of 6x9's but as with John I do a lot more miles on the road than on the track so mine will probably stay.

When I started using slicks my brakes were getting too hot due to the extra speed I was carrying along the straights so some brake ducting is next on my list,

Tony

 

[Diver944]

Getting the weight down is a very good way to increase performance and also give the brakes and suspension an easier life. Being the sad anorak that I am this is the weight (from memory) of the easy bits to take out according to my bathroom scales:

spare wheel - 16 kilos
rear seat back - 14 kilos
both front seats - 50 kilos (replace with one 8 kilo fibreglass bucket seat)
rear boot carpet - 4 kilos
set of floor mats - 3 kilos
empty the washer bottle - 5 kilos


You've nearly saved 100 kilos already and the only cost was £100 for the bucket seat.

To go further, the front wings and bonnet all unbolt simply and can be replaced with fibreglass items for less than £400 (unpainted) but you're now into diminishing returns as these will only save around 30 kilos. The same can be done by fitting a plexiglass hatchback, but this can be a nightmare to fit (speak to Peter Empson on the Titanic list).

So Fen how hardcore do you want to go [8D]

 

[Fen]

ORIGINAL: Diver944
So Fen how hardcore do you want to go [8D]

Lets just say that I found the Swedish site I posted last week when I was looking for Plexiglass hatches...

 

[Guest]

In my humble opinion the 3l turbo route is fine if you already have a 968 engine and transmission in the barn.
A friend of mine is currently building one on his '90 turbo out of his 968 CS (previously crashed by his best friend []) and is budgeting on a £3k limit, which he hasn't reached so far although he has already bought the main components (complete 2.7 head with cambox, Carillo rods, original Mahle 968 TRS pistons, etc.)

 

[Robbiemeister]

Fen

I'm no expert on this but what I have heard is that the engine looses reliability exponetialy as you get over 300 bhp.

I know someone who mechaniced on a racing 968 RS turbo which was a 3litre producing 440bhp. The catalogue of special parts was extensive, a lot of which are no longer available. A lot of ceramic coated stuff. All very expensive.

I don't know if the above is relavent to you but the car I own is pretty much waht you are planning in your first phase.

'90 turbo with an AMD modified engine, the graph says 301.

968CS M030 suspension

Standard brakes with hard pads and a bit of ducting

Stripped interior wth lightweight bucket seats, Corner weighting chart from Parr Garage says 1325kg.

17in Cup 1's with road tyres.

After using it this year for a few track days these are the things I need to go faster.

Tuition, tuition, tuition.

Bigger balls.

Sticky tyres.

Something to cool the inlet temp. in hot weather. It "seems" to loose power when its very warm.

Even bigger balls.

Hope this helps