Engine performance

[sawood12]

ORIGINAL: SUSIT



Now here is a very sensable post, Not sure why the cylinder head should be that difficult to improve on! My mates 2.6 LTwin cam chevette produces close to 265 bhp and serious torque, I will admit it does not have the largest of powerbands but that is not the point.

Ah, well I've misunderstood the original question then, because for me it is exactly the point. It is the area under the dyno curve that is important for real world performance and spiky narrow powerband bhp glory-runs are of no interest whatsoever and of no challenge. Good for dyno glory-runs and bragging rights down the pub. Sure, slap in a higher lift cam, advance it a few degrees, fit an intake manifold with a large plenum and short stubby runners, big bore exhaust, re-chip, solid lifters and raise the red line limit by 700 or so rpm and no doubt 250+bhp would easily be in reach, but it would be rubbish to drive (hence my Civic Type R analogy). I'd wager a standard S2 in fine fettle with its wide and relatively flat powerband would drive much better and be quicker real-world than your mate's shove-it.

Tuning really depends upon what you want out of the car in terms of how you want to drive it, and not necessarily what peak power and torque.

 

[Alexw]

I was tempted to get the cams looked at by piper when my engine was in but its turned out I needed a new clutch (PO fitted wrong one...) so that idea went out the window. I'd still like to see what can be gotten from more aggressive cams and a modern MAP ECU to make use full use of it. Someone somewhere needs to put forward the money if its ever going to happen. Theres a company in the US that does the 16v cams but I think it was for the 928 originally, I can't find the website now though....

As already said, I guess you don't see it because of the cost of it. Selling up and buying a turbo is much easier and the pistons arn't designed for FI, I recall a post by Barry Hartech saying the standard pistons are only good for a few psi extra.

 

[sawood12]

As always the devil is in the detail. You can spend alot of time changing individual aspects of the engine, but ultimately you will only get the main benefits if you match all the engine components so they compliment eachother. The standard cam is matched to the intake and exhaust manifolds and all the other components in the chain to achieve a specific characteristic of the engine with is so much more than crude headline bhp. If you went in and simply changed one aspect in isolation, like the cams for example, then you might be disappointed by the improvement, maybe only a couple of %. Then you start thinking "I'll just get a custom intake and exhaust manifold made to get the best out of my cam", then you're into the wonderful world of flushing your money down the drain for a relatively small gain.

Really if you want a huge step change improvement in performance out of your S2 then either sell up and get a turbo or install a an LS1 v8 (i think Promax are developing a kit). In the long run it will be alot cheaper and alot less hassle than tuning up the S2 engine and you'll end up with alot more performance than you could ever have got out of the S2 engine.

I can't wait to hear from the first running report of a Promax 944 v8!

 

[SUSIT]

ORIGINAL: sawood12

ORIGINAL: SUSIT



Now here is a very sensable post, Not sure why the cylinder head should be that difficult to improve on! My mates 2.6 LTwin cam chevette produces close to 265 bhp and serious torque, I will admit it does not have the largest of powerbands but that is not the point.

Ah, well I've misunderstood the original question then, because for me it is exactly the point. It is the area under the dyno curve that is important for real world performance and spiky narrow powerband bhp glory-runs are of no interest whatsoever and of no challenge. Good for dyno glory-runs and bragging rights down the pub. Sure, slap in a higher lift cam, advance it a few degrees, fit an intake manifold with a large plenum and short stubby runners, big bore exhaust, re-chip, solid lifters and raise the red line limit by 700 or so rpm and no doubt 250+bhp would easily be in reach, but it would be rubbish to drive (hence my Civic Type R analogy). I'd wager a standard S2 in fine fettle with its wide and relatively flat powerband would drive much better and be quicker real-world than your mate's shove-it.

Tuning really depends upon what you want out of the car in terms of how you want to drive it, and not necessarily what peak power and torque.

no doubt it will drive better than shove-it but said car still holds record at Doune Hillclimb[] to the best of my knowledge. But then it is an ex works tarmac rally car []
So was not really comparing like for like but its would seem there is no real work been done on the 3 L. there might be a challange worth looking at here.

Will admit, as a road car it does the job just the way it is and tick all the boxes on my lists, well it will do once the Tow bar gets fitted []

Now as a tarmac rally car, that might be worth a go [

Thanks for all the interesting replies guys

 

[Alexw]

yeah, thats very true, there all sorts of resonance in the intake and exhaust that I know makes a difference when you start fiddling with it. I'd like to see the first V8 form Promax too, look interesting!

 

[Copperman05]

I'm also interested in the V8 option, but sticking a wacking great bit of american metal in there isnt going to be cheap either, and I'm not just talking about the cost of fitting but the cost of running the thing. What does 6L drink? 15-16mpg? would turn a quite usable daily runner into a weekend toy unless you have lots of disposable cash, and thats not why I bought the 944 in the first place.

 

[333pg333]

The stock 16v head actually flows very well. I know people that have tested them. Of course you can make more power with new rods/pistons running higher C/R, new billet cams, possibly playing with intake and throttle body, and of course a standalone...but as Scott and others have mentioned, this will be at the sacrifice of day to day driveability. Again, you have to look at the US for people who have done all this before. Such a large market will generally mean that someone has been there/done that.
However looking at Peter Empsom's videos, I think the S/C looks to have definite merits and it would improve general daily driving on the whole.

 

[Peter Empson]

ORIGINAL: AndrewS

For example; there is a Supercharger conversion for the 944S2, but I am not aware of anybody that has fitted one (again, would cost more than the value of the car).

As Patrick mentions I have the SFR kit Andrew on the white car (albeit with a few changes from standard).

 

[333pg333]

Peter, you should put links to your trackday clips in your signature so people can see just how effective this setup is. Not to overlook your very tidy driving skills either. []

 

[AndrewS]

ORIGINAL: Copperman05

I'm also interested in the V8 option, but sticking a wacking great bit of american metal in there isnt going to be cheap either, and I'm not just talking about the cost of fitting but the cost of running the thing. What does 6L drink? 15-16mpg? would turn a quite usable daily runner into a weekend toy unless you have lots of disposable cash, and thats not why I bought the 944 in the first place.

My Monaro CV8 returns 14 - 30mpg. On a mixed journey, it will average 22mpg. That's in an 1800kg car. A 944 (with LS will weigh about 1350 kg) should achieve better consumption becuase it weighs a lot less.

Reliability and running costs are also a factor. The LS engines need very little effort to maintain and (if my CV8 is typical) never need oil (between oil services). You only need to change oil every 12,000 miles (Turbo is 6,000).

You're also looking at 325 to 450 bhp (depending on which engine you use) with huge torque from just 1800 rpm.

Couple that with standard 944 Turbo gearing and you are looking at a seriously fast car with up to 330 bhp / 1000kg.

Regards,
Andrew

 

[AndrewS]

ORIGINAL: Peter Empson

As Patrick mentions I have the SFR kit Andrew on the white car (albeit with a few changes from standard).

Hi Peter,

I forgot about the SFR conversion on your car. How's that working out and what is the max power, torque and useabilty like after the conversion?

If somebody was purchasing the kit from SFR, what do you think the UK fitted cost to a 944S2 would be?

Regards,
Andrew

 

[Peter Empson]

ORIGINAL: 333pg333

Peter, you should put links to your trackday clips in your signature so people can see just how effective this setup is. Not to overlook your very tidy driving skills either. []

[] Thanks Patrick, some vids are on the media page of my website linked below (only the last one has the SC fitted though).

ORIGINAL: AndrewS

Hi Peter,

I forgot about the SFR conversion on your car. How's that working out and what is the max power, torque and useabilty like after the conversion?

If somebody was purchasing the kit from SFR, what do you think the UK fitted cost to a 944S2 would be?

Regards,
Andrew

I don't know what the power is as its not been on a dyno yet, but it's a very big improvement over standard. Power delivery is excellent and lag free. This is with very conservative timing and temporarily mapped by an idiot (me). The standard SFR kit is more plug and play, mine has a few changes (piggyback, injectors etc). It seems just under 300bhp is possible at these low boost pressures once it's all optimised.

My engine is very worn (rings are shot - over 180k miles old, lots of hard track use so it wastes oil like BP) and the only real issue I've had is that the MAF seems to be getting oiled up due to blow by, a better catch tank should help this in the short term. In the long term I'm having a fresh bottom end built (as and when funds allow) with slightly lower compression ratio and this will allow us to run double the boost.

Fitting the SC is dead easy, can be diy'd or done by a garage pretty quickly (with practice it should be possible to fit it in about 4 hours I guess - less if you go for one without an IC). The purchase cost is quite high but then the procharger itself isn't cheap, however there are alternatives out there and it seems to be a growing market, with two new 968 kits out that can be adapted for the S2.

A V8 in a 944 still doesn't seem right to me (hasn't one of the US owners just sold his because he preferred the turbo lump?), but I look forward to seeing one and hopefully changing my mind.

 

[peanut]

ORIGINAL: Copperman05

I'm also interested in the V8 option, but sticking a wacking great bit of american metal in there isnt going to be cheap either, and I'm not just talking about the cost of fitting but the cost of running the thing. What does 6L drink? 15-16mpg? would turn a quite usable daily runner into a weekend toy unless you have lots of disposable cash, and thats not why I bought the 944 in the first place.

so what kind of fuel return were you expecting with a turbo or super-charger or other engine mods ?

maybe you should be thinking of sticking a diesel in there instead [][][]

 

[morris944s2john]

Part of the problem may be not real lack of performance- but perception of lack of performance. And perception is not reality!

What works for me is to also run a genuinely slow car (Morris Minor) and when you get in your 944 it will be fast again![]

 

[morris944s2john]

Another much cheaper way to BIG V-8 power is to fit a Rover V8 and supercharge it. The Rover V8 is a well known quantity for tuning and parts are easily available and they sound great! And they are very DIY friendly being carbs and old fashioned ignition.

I know of a chap local to me who has fitted a supercharged Rover V8 to his classic car and he gets 300BHP at the wheels and it sounds fantastic!

 

[peanut]

yep the Rover lump is a fantastic engine. After years of MGB's and Datsun 240Z's I could never go back to carbs []. Did no-one ever inject the Rover lump ?

 

[morris944s2john]

The later 3.9 Rover V8's - as fitted to the Range rover- were fuel injected, and the 90's TVR's. But what is wrong with carbs??? I have had four cars now with SU carburettors and apart from needing the occasional clean these are very reliable and easy to set up items.

I understand SU carbs but fuel injection is a mystery to me!

 

[peanut]

ahhhhhh carbs mmmm most like the SU's and Stonbergs are a very crude fuel delivery device compared to injection.
My S2 starts and runs from -30 without a single cough splutter or hesitation ever! thats amazing imo . Carbs you can keep em []

 

[Mike_Pollock]

I've been round Silverstone with Peter and in a very well sorted 968 with a similar standard driver, and the supercharged 944 is certainly faster down Hanger
Mike

 

[Tam Lin]

ORIGINAL: Alexw

I've not idea about fitting larger diameter valves, I'm guessing theres no room.

Didn't Porsche set a precedent? The 968 has essentially the same head, but with larger intake valves. Seem to work OK, although famously seeing 240 BHP in a standard 968 is rare, and that's with MAF and of course cam timing.