3 litre 944 Turbo on track

[TTM]

I had also understood this engine was a resleeved 2.5...

Have the 968 pistons been machined to lower the compression ratio?

 

[Diver944]

ORIGINAL: TTM

Have the 968 pistons been machined to lower the compression ratio?

Yes

 

[pauljmcnulty]

Here's some pics from Wednesday, you'd never believe it was a blue car until you see the engine bay shot at the end

I can understand that the blue looks dark with the bad colour balance, but how did you make the wheels go from silver to black? []

 

[Diver944]

The black ones had sticky track tyres on, it was waaaaaay too slippy for them in the morning so we changed them at lunch time

 

[sawood12]

OK, so it appears to be a relatively cheap 3.0 ltr build but utilising a 968 bottom end - however on the PH thread he did register some concern about the stock 968 pistons didn't he? Seems to me that if you end up having to upgrade pistons (i.e. if you are going to tune the thing up) you're looking at massively increasing the cost of the project - mind you I like the idea of it and anyone trying to do such a project on a shoe string is crazy. Still i'd prefer a turbo'd 968 engine, head and all with some fancy intake to take proper advantage of the variable valve timing (no point puting a fixed configuration intake on a variable timing valve head!). Shame someone doesn't fabricate an exhaust manifold kit that bolts up against a 944 turbo crossover pipe.

 

[Eldavo]

ORIGINAL: 944 man

Its a 2,500cc engine sleeved up to 3,000, retaining the original 951 head.  The 16v head doesnt work well with forced induction.  A 2,700 base engine wouldnt need liners, only an S2/968 crankshaft to make it up to 3,000cc.

Simon

So if I managed to get hold of an S2/968 crankshaft and fit it into my 2.7 then I'd effectively have an 8v 3.0L? Interesting, cheap horsepower or no such thing?

 

[944 man]

Yes. The crankcase used in all normally aspirated 1989 model year onwards 944s is the similar. Tis being the case a 16v 2.7l or an 8v 3.0l car are both possible. Whether the pistons will suit isnt a question that I can answer though.

 

[Eldavo]

Oh, maybe not then!

 

[sawood12]

ORIGINAL: Eldavo



So if I managed to get hold of an S2/968 crankshaft and fit it into my 2.7 then I'd effectively have an 8v 3.0L? Interesting, cheap horsepower or no such thing?

Cheap horsepower is possible. Cheap and reliable horsepower is not! It is the tuning holy trinity - low expense, high power, good reliability - you can have any two, but not all three.

 

[Eldavo]

I'll just cut some holes in the floor and do a fred flintstone instead!

 

[DavidL]

Do we have any idea of cost on this engine? Baz was somewhat vague on PH when asked. He pointed out that the cost would vary considerably depending on where you started form - not unreasonably - but no actual figures were mentioned either.

 

[sawood12]

As with everything like this the cost of the engine upgrade is just the start. Then there is all the stuff that bolts onto and around the engine, then there will be the suspension, brakes, gearbox/diff, wheels and tyres (what good is high HP & torque if you can't get it onto the tarmac) then you'll be starting to think about things like traction control - there has been alot of chat on other forums about this amongst those with big HP/torque 944 turbo's and not one of the possible solutions is cheap. To do the job properly and completely you're looking at £20k+ at least. To do a proper job on the engine alone will cost you in the region of £15k - unless you do alot of the work yourself.

 

[MarkK]

Traction control!!!?????????[&:]Wheres the fun in that??!!![]

 

[Neil Haughey]

ORIGINAL: sawood12

ORIGINAL: Eldavo



So if I managed to get hold of an S2/968 crankshaft and fit it into my 2.7 then I'd effectively have an 8v 3.0L? Interesting, cheap horsepower or no such thing?

Cheap horsepower is possible. Cheap and reliable horsepower is not!  It is the tuning holy trinity - low expense, high power, good reliability - you can have any two, but not all three.

Doesn't mean though that expensive always means good or the best, as with most things there will always be a sweet spot where bang for buck is optimised. Across all cars this tends to be somewhere in the realm of modest tuning.

 

[sawood12]

I think the addage assumes that expense is expense well spent, but I think you're right Neil, that is why that after my modest experiences in messing around with 944's has taught me that you get far more reward from mods that improve handling like KW suspension, rather than mods that increase power. I'd be willing to wager that KW would improve your laptimes more than a pretty sizeable chunk of increase in power and it improves the driving experience all the time you drive it and not just on the occasions you are able to get on the power.

 

[Hilux]

(what good is high HP & torque if you can't get it onto the tarmac) then you'll be starting to think about things like traction control

Dont need TC. Instead a torque sensing diff or a rebuilt LSD with lower proportioning bias would be better. The original LSD`s are all knackered unless rebuilt so its possible in the wet to go sideways in a straight line.

Doesn't mean though that expensive always means good or the best, as with most things there will always be a sweet spot where bang for buck is optimised. Across all cars this tends to be somewhere in the realm of modest tuning.

Spot on Neil

A car will always be quicker if its useable power you can reliably put down and is lighter so the PTW ratio improves. You want to be able to use the throttle in a bend as required so you can progressively nail it out of a corner instead of feathering it in case a huge gob of power sends you off and the less weight the less momentum in changing direction. The power you want is via torque, a nice flat torque curve so you have useable power whenever you need it and not peaky power that comes in with a bang at high revs or with a huge boost surge. My old 944T had only 253bhp but better torque than some others that had been 'enhanced' and as power is simply a function of torque was an absolute flying machine through the gears []

Entering a corner quicker (better brakes - pads and fluid are all you need with medium blacks), and rounding corners (better suspension - Mo30 is old hat and soft) and improved weight transference (better ARB`s - 968/Mo30 are definitely too soft) with more power (lightening the car by 50 kg`s is worth some 10-15bhp) are all positives and cheaper for track days etc than spending enough on an engine that would buy you a 400bhp E39 M3 to have as well as your 944 [] and then having to uprate everything anyway to cope with it.

 

[sawood12]

LSD and trick diffs will only ever allow you to better exploit the grip available to you. A torque sensing diff will only distribute torque according to the grip available at each wheel. If the total amount of torque available at the wheels is greater than the grip afforded by the contact area of rubber onto tarmac then you loose grip therfore TC is needed. And there comes a point where forever increasing tyre width to get more rubber in contact with the road becomes counter productive. If you've got a 944 turbo kicking out 400bhp+ and 400 ftlb torque then no amount of diff trickery is going to prevent you from loosing traction if you give it too much welly - to you either employ TC the manual way i.e. by the right foot, or by electronic purposes.

Either way I agree with the sentiment Neil has explained - If you're having to employ TC in order to deploy power then what's the point in chasing big HP's if you can't deploy them. Far better spending your money on chassis mods.

 

[Diver944]

One thing is certain. You definitley don't need traction control or trick LSD's to put the power down with this 3 litre Turbo.

When you actually drive this thing you will see straight away that those issues are simply not a problem. The power and torque is made so effortlessly and so linearly that this car really does feel almost as if it's normally aspirated. Ths use of a larger engine and a slightly undersized turbocharger gets rid of all the lag, all the sudden onset of boost and leaves you with a car that is very easy to drive. Wednesday morning was very wet, very damp and very slippy yet this car was easily controlled in spite of it having very old Continentals on the rear.

I'd also stick my neck out and say that anyone wanting to chase big power would simply need to replace the standard exhaust with a freely flowing 3 inch version (this one even had the cat still fitted) and you would possibly see the power level increase to somewhere round the torque level of 350.

The cars on Ricks Dyno tables with similar numbers are all running around 1.2 bar boost compared to 0.8 bar on this one, and they make their power much higher up the rev range

 

[Hilux]

so linearly

Thats the key to it.......................linear torque equals even and progressive power throughout the range

 

[944Turbo]

having owned a relatively high power 944T for 8 or so years driven year round, I can only really remember one occasion where it got scary without traction control. It was very wet, an uphill gradient and I ended up very crossed up on some mud at about 85 in third when crossing some mud - that got the adrenalin pumping, but it was easy enough to catch.

In snow on sheet Ice on the A31 Hogs back uphill it was useless on boost just got sideways as soon as any boost built, off boost it was ok - again exceptional circumstances though.

I realise I haven't made it over about 350bhp with similar torque but thats plenty on a slippery road, never found it uncontrollable though, the pedal on the right and the round thing in the middle keep it in check.

Tony