3 litre turbo conversion??

[nicksonmsport]

i have an s2 for breaking so wanted a bit of info on using the 3l bottom end for turbocharged cars.

whats involved? is it worth the hassle? am i right in thinking u use the 2.7 head and does this just bolt on or need mods

can someone break down the main jobs and the pain in the arse parts. then i can decide wether its worth me keeping the bottom end from the s2 to one side as a project

many thanks
nick

 

[u63af]

I looked into this and the cost to do it properly is pretty significant.

You basically start with a good 3.0 bottom end take. You can either machine down the pistons to lower compression or buy forged pistons and rods. I was going to buy wossner forged rods and pistons (this is circa £1300 for parts). The 2.7 head mates straight to the block but you are best changing the 2.7 exhaust valves to turbo ones. the turbo ones I believe are 1mm longer so need to be machined slightly. After this, you need to get some form of chip to ensure fueling etc is ok.

The costs are a lot as you ultimately end up getitng carried away such as uprated turbo, then maybe stand alone ecu or vitesse kit etc.

I was trying to do it on a budget and still think it would have cost over £4k by the end of it.

I am now just sticking with the 2.5 as I was concerned about the reliability of a 3.0

 

[nicksonmsport]

is the block the same as the 2.5 then, with regards to being able to just bolt ancilleries /transmission up to it all etc. and does the same apply for the head, will everything just bolt onto it, or is there more involved?

the main thing im bothered about is the work involved to the actual engine itself, bolting the head to the block and any other work thats involved. i can build the engine myself and do all fabrication work and mechanicals. its just some people say u just get a block and then bolt a 2.7 head to it. when in reality there is much more work involved than that! with mods to the block and head to make it work


why are u concerned about 3 litre reliability ? surely it would allow for lower boost levels to be run over a 2.5 ?

 

[Mike_Pollock]

All 2.5 - N/A and Turbo - have same block and the 2.7 and 3.0s share a block.

 

[JamesO]

If you use the 2.7 head then the only issues are (aside pistons and rods) are the coolant elbow on the top of the head will foul the intercooler pipe and the oil feed to the turbo will need drilling out and tapping. Oh and the head studs will need to be shorter.

Everything else pretty much bolt on. Even the exhaust valves from the turbo head will fit the 2.7 head. One thing that nearly caught me out is the crank pulley needs to be the 8v one as the size is different.

 

[nicksonmsport]

so the actual engine build itself is easy enough! especially if building myself will save a lot of labour money. the hard part seems to be sourcing a 2.7 head, although i suppose you could buy a complete 2.7 car for not alot of money and take the head from it

after looking about it seems lots of people run the vitesse maf kit but is £1400 !

surely its easy to just run a cheap aftermarket standalone such as an emerald ecu that will control a 4 pot turbo with ease! and get rid of the maf/afm and run map sensor instead. emerald ecu is like £600 ! i have seen twin turbo v8's running on it with 800bhp!
why do i not see many 944 turbos running standalone management?

 

[nicksonmsport]

james0 how do you find your 3.0 turbo? can u give me more details on the spec and power/torque figures. also wheres the best place to get engine parts such as the pistons/rods for the 3.0
thanks

 

[TTM]

Thankfully, the difference being that when you finally get up top you do feel like your feet don't touch the ground anymore []

 

[JamesO]

Couldn't tell you the power figures as I don't know myself
Mines very much a budget build as I had a rotten 2.7 which had a 968 engine with a lunched head running Microsquirt, a 1986 turbo in bits turned up cheap and I built it from there.

The 2.7, S2 and 968 share the same block but the 968 has piston squirters. The 2.5 head can be modified to fit the larger block too.

I used the 86 rods from the turbo which are the strongest Porsche made and used the 968 pistons as is. Which means I have to keep the boost down to a modest level for now.

I do plan to change this (lower compression and bigger turbo etc) .
It's done about 8000 miles so far and is great fun, traction is a bit of an issue in the wet though and I have managed to break the flange where the torque tube mounts to the transaxle with a ham fisted downshift. Also killed the diff carrier bearings in pretty short order but they had plenty of miles on them.

 

[944Turbo]

Standalone is possible and has been done, but the rolling road time to set up can be significant and expensive. There are some tricks to getting the best from this engine. Some years ago we were suprised at a dyno day when cars running off the shelf generic chips outperformed cars that had been custom mapped here in the UK by a respected specialist. Rick ran a wolf set up from Lindsey racing which had base maps but spent many hours and pounds to get to 400bhp (from a 2.5) and good manners. I imagine mark and promax also spent a fair amount of time with a dyno, to get his car running right, and lovely car that it is, it is quite peaky, I seem to recall at 3,000 rpm it produces less power than standard. Thom has a 3.0 turbo and I think he abandoned the vittesse setup in the end and went for something more exotic.
Tony

 

[nicksonmsport]

think i will speak to jm garage and see what the general route is.
can anyone tell me the mods required to get the turbo head to fit the 3l bottom end, seeing as i already have a turbo head, and im a fabricator, it makes sense to do this rather than find a 2.7 head. as long as the mods are not to extensive or expensive to do

also where to find forged pistons/rods for s2 bottom end

thanks
nick

 

[nicksonmsport]

as another option for maybe saving time/money?? is it possible to fit a 3litre crank with 88mm stroke rather than 2.5s 78.9mm, this would increase displacement to 2.763 litres. this way no head mods would be required, would the turbo std pistons work, or would the piston height cause issues with compression ratio or collide with the head etc??

is this possible??

 

[nicksonmsport]

ok i have found a bit of information that states the 3 litre crank can be used, along with the std turbo rods, but new pistons with offset gudgeon pins are required to achive the right tdc position.
the block will need a small amount of machining to ensure everything can turn in the casing. mainly rods hitting the block due to extra stroke. this isnt a problem for me as i have access to a machine shop etc.

it seems the pistons are mahle items, does anyone know who can supply these pistons.

many thanks
nick

 

[Lowtimer]

The 2.8 stroker is a fairly common conversion to the 2.5, yes. I suspect you need new rods as well as pistons. The most knowledgeable people on this subject generally seem to prefer Carrillo rods and Mahle pistons.

Probably the best site for technical discussion of the detail of large-capacity 944 conversions is Rennlist: http://forums.rennlist.com/rennforums/944-turbo-and-turbo-s-forum-72/
A series of searches on that forum will find you details of how other people have done these conversions in detail.

You could try the following:
http://forums.rennlist.com/rennforums/944-turbo-and-turbo-s-forum/582303-whats-involved-in-a-2-8-or-3-0-build.html
http://forums.rennlist.com/rennforums/944-turbo-and-turbo-s-forum/64795-whos-running-a-2-8l-street-car-or-knows-a-lot-bout-them.html
http://forums.rennlist.com/rennforums/944-turbo-and-turbo-s-forum/164024-2-5-2-8-conversion.html
http://forums.rennlist.com/rennforums/944-turbo-and-turbo-s-forum/460264-how-much-power-can-one-expect-to-gain-from-2-8-stroker.html
http://forums.rennlist.com/rennforums/944-turbo-and-turbo-s-forum/335141-2-8-getting-closer-pic.html
http://forums.rennlist.com/rennforums/944-turbo-and-turbo-s-forum/373988-2-8-rebuld-goes-full-throttle.html

For larger conversions i.e. 3.0 and 3.2:

- Barry Hart also had a long running thread on the development of the low-cost Hartech 3.0 Turbo conversion over on Pistonheads here:
http://www.pistonheads.com/gassing/topic.asp?h=0&f=48&t=766383

- and one Rennlist thread in particular is that belonging to Diver944, Paul Smith, who is also on here. His 3.2 thread is here:
http://forums.rennlist.com/rennforums/944-turbo-and-turbo-s-forum/319420-uk-3-2-turbo-hits-the-road.html

 

[nicksonmsport]

thanks for all that info mate. it seems you dont have to use new rods, as long as you use the offset gudgeon pistons. if you didnt use these pistons then you would need shorter rods yes. im told the std rods are good for 500bhp anyway? although depending on cost of forged rods it may be worth doing them while the engine is apart!

thanks for the links, will take a good look at them. i think the 2.8 stroker would work out to be the most cost effective way of gaining some torque and power without going crazy.

 

[MarkK]

Yup power does come in with a bang[],but in it's defence it is a very quick and drivable car in the real world not just a dyno queen, Alot of fun to drive and compared to some of the cars knocking around at the time it would seem it is one of the more reliable conversions.....,I have driven it on many long journeys including trips to the Ring,Spa and last year a day at Brands Hatch it's regularly used in better weather as I don't like it out in salt if I can help it,it stays plugged in on a trickle charger and is ready to go at any time.No weird behaviour just twist and go....
I just changed it to road tyres and a set of gloss black CS wheels[8D]

 

[333pg333]

I think you should still contemplate using the S2 motor in it's entirety...well almost. By this I mean that whatever you do amongst the choices aforementioned, it will most likely involve a bit of custom work and also either a new ECU or something like a Vitesse kit. If you are a good welder or have access to someone who is you can put together a very nice 3L 16v turbo with the engine you have. My friend and mechanic has done just this with an S2 motor. He bought an Inlet manifold from Speed Force Racing but you could get someone to put something together in the UK. He then customised the exhaust manifold to combine the S2 and 951. Plus also made some hard pipes for the Intercooler. Having been successful with Vitesse products previously he stuck with one of these.

Here is a link to a thread showing both his and a customer's car.

http://forums.rennlist.com/rennforums/944-turbo-and-turbo-s-forum/520900-3ltr-twincam-engine-coming-together.html



Here's some links to show how this car goes on the track. Note that this car is a full daily driver with no lightening done to it. Full leather interior, full working A/C and heating, music etc...

http://www.youtube.com/watch?v=HkC4n8TqkYA

http://www.youtube.com/watch?v=GFPQ6K4galA

 

[AndrewS]

ORIGINAL: MarkK

Yup power does come in with a bang[],but in it's defence it is a very quick and drivable car in the real world not just a dyno queen, Alot of fun to drive and compared to some of the cars knocking around at the time it would seem it is one of the more reliable conversions.....,I have driven it on many long journeys including trips to the Ring,Spa and last year a day at Brands Hatch it's regularly used in better weather as I don't like it out in salt if I can help it,it stays plugged in on a trickle charger and is ready to go at any time.No weird behaviour just twist and go....
I just changed it to road tyres and a set of gloss black CS wheels[8D]

Hey Mark, Glad to see your 400+ (when Dyno tested) 2.5 red car is still running well 6 years later. We recorded 441bhp at Wayne's facility (Runcorn) and 400+ bhp two days later at Weltmeister - the car had difficulty gripping the rollers (at WM); hence I am sure we would have seen a different torque curve with some super sticky rubber. ;-) The car has been reliable.

All,
3.0 conversions are possible as are the 2.8 stroker conversion (my original 2.8 is still running [after a light refresh], 13 years after the original 1999 upgrade in Eire). Doing a full on 3.0 conversion is expensive to do properly - but Barry Hart has done a reliable conversion before (in the UK). Special attention is required to manage the cooling of the 3.0 barrels (as they are all joined together unlike the 2.5) and the 2.5 head needs modifying to mate to the 3.0 block (2.7 head can be adapted also).

Regards,
Andrew

 

[MarkK]

Cheers Andrew[]
Time flies eh!
Car is Ace still[]

 

[Robo1968]

I've had my 3.0 Turbo for about 2 years now, the motor is so much better than the 2.5. If you can do the work yourself or parts of it then go for it.

I only realised just hoe fast mine was when I drove a standard 2.5 the other day, completely different car