SirLapsalot

Hmmm.... I posted some data showing EBR from my car and have spent a lot of time calibrating my engine from a clean slate on the dyno and on the road, using audio knock detection every step of the way so that I could both see and hear where the knock threshold was.

Data and actual experiencetesting a theory or industry accepted knowledge/trend, using our specific cars/applications is helpful for the community. Non-technical and immature rhetoric like you seem to be an expert at providing is not so helpful....

333pg333

Pretty sure he's still using product from Vitesse. They've not let him or his customer's down yet. Maybe a little old school although I have no confirmation as to what config they are these days.

blade7

You're entitled to express an opinion, but apparently all the "internet experts" aren't worthy to do the same. You do know what opinions are like though?

Penguinracer

There's no question that the 16 valve head is the way to go, but for a long time finding someone to fabricate the intake & headers was difficult and expensive.
The other challenges have been aftermarket cams for reduced overlap, setting up a twin pulley system so that exhaust & intake cam timing can be changed individually, ditching the stock tensioner & finding sufficiently heat resistant exhaust valves. All these things have been overcome but it's been time consuming, expensive and involved.
If you're starting from scratch & storing your original block then obviously you'd start with 16 valve suited pistons.
While some have built reliable 16 valve street cars by reusing as many stock S2 internals as possible, to me a strong 16 valve motor would have a standalone ECU, twin pulley set-up, custom cams, closed deck, steel / ductile iron bores ,dry-sump & inconel exhaust valves - and that won't be cheap.

Penguinracer

Throw in your custom pistons & rods, bigger cooling systems, intercooler, uprated fuel system, oil cooling etc and before you've even touched your brakes, suspension & transmission - you're into serious expenditure. I think at it's core the economics of 16 valve v 8 valve which divides people not the engineering advantage - law of diminishing returns and all that.

SirLapsalot

Lol idk what you are talking about or trying to infer but thank you for the comic relief.

blade7

You're welcome.

sherry66

Why ditch the tensioner , once set it’s locked of .

Apart from that got everything else on your list and will never add it up !

Penguinracer

Sherry, I think a twin pulley set-up with custom cams would allow optimisation for a turbo motor, the stock cams may work but they weren't designed for forced induction & being able to independently time the intake & exhaust cams provides more tuning flexibility.
Does anyone make custom cams for a twin pulley arrangement for these motors?

nick_968

The point of the 16v is you don't really need all of that. You can get 500+ hp with a stock top end and much wider power curve. Sort the bottom end and you are good to go. You don't need a bigger rad. Bigger intercooler is a nice to have for more flow but that also applies to 8v. Same for oil cooling. On my 968 the stock oil cooler is just fine. Everyone will approach it differently but it doesn't have to cost a fortune. Years ago it was a big deal but it doesn't have to be now. Lots of people spend a fortune chasing top end on their 8v's, myself included but now I realise you just reach the limit of the head. Sensibly done 16v there is not much in it but far better reward. This is speaking as someone who still has a 3.0 8v!

sherry66

I have a pair of piper 968 cams that were ground to a profile that Baz had done to run with my twin cam wheels .
Also I think Michael Mount had some cams a while back that were adjustable but memory is fading .
Not so many builds anymore .
Look forward to your pictures .

bergerac

There definately a lot of people around doing things that are 11 tenths for a street car, the challenge is finding the safe middle ground that doesn't result in damage or a rebuild.

333pg333

I think you can look at it from both camps depending on what you want from the car. Yes, it can be done on a cheaper budget if you utilise and/or reconfigure some stock components. Even better if you can do the work yourself. JET951 / Sean Buchanan a perfect case in point. My understanding is that Sean just changes over his headgasket once a year prior to the club racing season and uses a good quality oil with decent film strength and ZDDP. Wossner rods/pistons (before the issues). Stock head studs. Stock crank. Stock oiling system. Stock intercooler. An SFR intake sits over a Vitesse turbo (and electronics) He used an S2 head and modified the stock turbo headers to fit. Stock S2 cams. Stock 951 gearbox with uprated Guards LSD and S2 cwp. Uprated brakes and suspension. While this isn't built to the n'th degree, it has lasted well and provided the opportunity to drive to the track, cut some laps and upset the GT3 owners then drive home. Daily driven to work and shops all year. Not a bad advertisement.

But is it not also worth trying to modernise the package? Where to start...more crucially, where to stop? Stock head/cams flow well enough but of course they can be improved upon. As we've seen, we can achieve very decent results on relatively low boost. To refer to Penguin's other thread. Can we make a 400whp reliable match for a GT3? I'd say even with a 16v stock head and 16-18psi you're going to be right there. 18psi shouldn't be too much of an ask. Especially if you have access to E85 or race fuels. However we do have to still consider cylinder pressure and headlift. As noted above, Sean continues to use stock head studs. But there are stronger/larger options out there. Though you do have to consider the age of these blocks and whatever their metallurgical history is. You can further bolster them with a sert. (ps make sure it's the right one. I learned a VERY expensive lesson!) What about a deck plate? Hmm...well, yes they do make sense, but they have to be done correctly otherwise they can lift or deform. (another lesson learned...) We've gone with MiD sleeves this time 'round. (bad pun..sorry). If installed correctly they should perform a similar function to a DP.

Intakes: There seem to be a couple of offerings. SFR (which I didn't love when I saw one up close), Heyward I think make one or are making one for the 16v. You can cobble something together with the stock runners and a welded plenum or even convert an aftermarket plenum from a different platform. Alternatively you can get a shop to weld one up without too many issues. Last and certainly not lea$t is to get one CNC'd.

Cams: Stock will work without being ideal. Not much off the shelf. Can't remember if JME even did 16v cams? RS Barn did some but I'd say mainly for n/a motors and I think they've ceased trading. Piper cams seem to be the best option. Pretty sure Jan @ DRS does some affordable adj Cam drive gears?

Exhaust: As noted above, Sean combined the stock 16v and 8v to make them work. I think SFR do a 16v set. Obviously after that you can go to an all out full custom setup which is probably the best.

Turbo: Your choice. Plenty of options although not so many that bolt on.

Electronics: You can start with a Vitesse system which will utilise stock harness and be relatively plug n play. After that you could go down the Megasquirt route which would be the cheapest aftermarket ECU offering. From what I've read, their current products are a lot better than the early days. I think it's a given that no matter which brand of ECU you opt for, go with one that your shop is comfortable with and has many successful results. No point going for the latest model 'Skynet 2030' if nobody near you works with it. You are going to need to upgrade your harness too.

Dry sump: Definitely a nice idea. If it's a street car where to put the oil tank? Is it 100% necessary? Seems not to be. Again, really depends on what you intend for your particular build. If you track it regularly with sticky rubber then, yes, DS becomes more important. Some years ago I had a trick wet sump made up. I think it was a pretty decent alternative to a dry sump. I would consider something like this again for a street car.

Driveline: Obviously our old H pattern 'boxes are just that, old. But there is some satisfaction from 'getting it right'. Our cars are old so why not stay in keeping with the era? What are the alternatives? Not much and certainly not much that doesn't blow out the budget. We're going to try converting to DBW and minimise boost loss during shifts through some electronic mastery. As far as standing up to the stresses of 400-600+hp with the stock gearbox, it's possible. Obviously hard launches aren't a good idea. It will probably be the driveshafts / CVs that fail so perhaps that's not such a bad thing having a 'fuse' in place. You can uprate these too via the Driveshaft shop. How fast do you need your car to go top speed? If it's not much over 145-150 mph then swapping in the ring & pinion from the S2 to the stock 5 speed 'box is a good option. Really livens these cars up but at the cost of raised rpms while cruising on Motorways in top gear. About 15% final drive loss iirc. There are a few options for LSD too.

Brakes: Big Reds and the larger rotors will be ok for most people. Otherwise go with some other choices out there. Custom options aren't as expensive as you'd think.

Suspension: Plenty of options to chose from.

Spindles/uprights/knuckles...call them what you might. The stock ones have been around for ages and I'm sure the factory didn't ever think that these cars would be modified to such an extent as we're discussing. Much bigger than stock wheel/tyre combos. Rubber replaced by metal or monoball parts. Some racecars with pretty hefty downforce. Not to mention just hitting the kerbs at the track. This all must be putting the stock parts under enormous stress. Not to forget the bearings which are undersized for the exercise. We repack front bearings before every meeting. Alternatives? Well there's nothing off the rack. I priced a set of one off customs made locally over 5 years ago. Even back then it was $5k+ and in a more recent discussion he said closer to $10k now just based on how few they would sell. Group buy anyone?
I've just been told that Jan @ DRS is going to produce some which while expensive, will be a lot cheaper than the ones from down here. As to the physical difference, I haven't seen either.

What else: Bigger wheels / tyres. Lighter CS/RS type body panels? Upgraded cooling package? 1/2 cage? Full cage?

Is this all nutz!!?? Yes, most definitely. What is the satisfaction factor? Pretty damned high if you pull it off. Can you enjoy it? Depends on where you live. We probably have more space per capita of any country in the world yet our national speed limit is 110kph/65mph. So as a street car it's in no way worth doing. As a street/track car...sort of, but still too easy to lose your licence and not being able to drive to the track. As a track only car, again, sort of. But with all the money that you can sink into one of these old cars, it would be much more advisable to pick a different platform where there are tons more parts and support available. Where there will be cars that other people have spent time and money setting up and will be a fraction of the cost to do the same in a 944/68. In the end, it's all a sort of madness from where I sit.

bergerac

Why do it? because we can! Life's boring if you play it safe. Would be madness pay someone to do it though. There was a turbo S2 that I'm pretty sure Sean built for sale last year, claimed $200k spend, sold for $44k.

Really don't buy this idea of buying a 500hp 'tune' for a modern BMW, we all know enough about cars to know this isn't the way you do things if you want a good long term result. The dyno charts I've seen have been horrible as well.

Droops83

Interesting reading, I have read this forum for many years but had not stumbled across this thread until today. It seems that Voith was prepared to die on his 2 valves/cyl hill . . . . and perhaps he did?

After over a decade of flogging my stock-engined 951 on track (driving to and from events, with it being my daily driver for much of that time), I acquired other cars and finally decided to modify the (tired) engine and have some fun. The modifications can be seen in my signature below, nothing ground-breaking, but it whetted my appetite for more. Not for pushing the envelope with an all-out racing engine, but simply having a more modern setup that could make greater use of the standalone engine management system I have (or perhaps another type depending on ultimate setup).

The problem is, here in California, the smog/emissions test has a visual component. I can switch back from the wasted spark ignition to the stock 944 "distributor" and tune the VEMS to pass the emissions test even with 800cc fuel injectors, but it is an annoyance. 16V swap would not be legal, nor would the VAG 07K swap that I would like to do even more.

In other news, I recently bought a 944S2 cabriolet for cheap off a customer (original owner, in fact), had a smoked clutch and broken convertible top, but otherwise quite nice. I was tempted to steal the engine for my 951, but I have been enjoying the car so much as is that I am keeping it intact. I never thought I would enjoy a guards red midlife crisis convertible so much, rubberiness and all!

Given my options, the 07K swap would be the way to go: same upsides of a modern cylinder head design with vastly improved flow, except with a lighter, smaller engine that sits further back in the engine bay, and eminently replaceable engine parts if something blows up---cannot be said for 944S2/968 parts! Sure, the existing 07K swap kit costs money and more work is required for plumbing and other matters, but this might be the same in a high-end 944/968 16V setup with custom intake and exhaust systems.

In the end, technology has advanced quite a bit in the past couple of decades. Excellent engine management systems with flexible sensor options allow for datalogging as shown above, so one can analyze said data and tailor their setup to suit their needs, whether 951 8V, 968, K-swap, or whatever!