NineMeister

For the strongest idle performance you need to use a 1.0bar MAP sensor piped into the intake plenum which provides a correction to the main fuel table as the idle valve opens & closes; the 0-100 correction table (zero MAP = -100% fuel trim, 100MAP = 0% fuel trim) is there for this reason. If you do not have a MAP sensor you should set the sensor default value to 100 which would then fix the fuel correction factor to 0% and you would run purely on the numbers in the main fuel table.


We've run a TPC supercharged 964RS on a 9m Motec M48 conversion some years ago and achieved great results. The only aspect that you need to be aware of is heat in the intake manifold because one of the hidden reasons why TPC use a 7th injector in the intake is to use the latent heat of the additional fuel to cool the intake charge to an acceptable level. With Motec and 6 larger injectors you do not have this advantage, so a charge cooler is going to be an essential upgrade if you are to keep a lid on the intake temperatures.

The 9m 993+3 conversions pass cat/smog testing in the UK, however there are some new developments planned for the new year that will see a quantum leap in the performance of our top end 3.82 litre racing engine conversions, the hope is that we can filter these developments down the ladder to provide similar and affordable improvements to the "lesser" packages. Watch this space!

Juha G

Yes, that makes sense and explains it.
I don't have the MAP sensor installed yet so running purely on the alpha-N information. I have a MAP sensor from Motec for which I will make yet another adpator harness so that I can plug into the MAF wire connectors. (already connected to the Motec via the original engine harness).




Yes, I am aware of that and will install a water/alcohol injection system to lower the temperatures. I had such system on my 550hp supercharged E46 M3 and it worked like a charm.

I don't know anything about the smog testing in UK but in Finland they measure the emissions at idle and at 4000rpm, with no load on the engine.
The HC limit is quite easily exceeded with agressive cams like on your engines because of the overlap.

I will stay tuned on this channel Colin!!!

evoderby

Just buy yourself a bog standard used engine to drop in during yearly smog testing, I would guess a yearly 'engine out' servicing would perfectly suit your 9M vr3 engine anyway ;-)

Juha G

I have to admit, it has crossed my mind...

On the other hand, I'm quite lazy and the ticket for driving with an un-inspected car is only 60 euros...

That is the 1st infraction though and they usually do take your plates and to get them back, you have to have the car pass the inspection.

I can do a BMW six cylinder engine out and put it back in just one evening (and a keg of beer). I have never dropped the 993 engine but I can imagine it will take a lot longer than that...!?

Macca

Hi Colin,

Thanks for the info. Flap closed to approx 5500 then open. We'll check on the dyno as you say. Do you have a TPS% condition set (i.e. >60%)?

When the car idles 950rpm hot its rock steady using the needle as reference. The idle is however quite a different sound than when its idling at say 1000 rpm. Its more a "romp" romp romp sound. Its sends a shimmy through the car body (bit like a hot Amercian muscle car). It can probably be tuned out a bit but is this characteristic of a lumpier cam with a LWFC and lower inertia pulley hardware?

Thanks again.

NineMeister

I open the flap with TPS > 50% of fully open.

On a common plenum installation, idle irregularity is more than likely down to a small difference in the camshaft timing between the left and right banks of the engine. This is why we now use electronic digital measuring equipment to get the left/right lobe centrelines within 0.10 degrees of each other.

Macca

Thanks Colin. +5500 rpm, +>50% TPS Open flap. Got that. Low side (ground) activates the flap open from memory?

Can the cams be degreed without taking the engine out and the cam tower covers off etc?

Thanks again.

camlob

Wow! That instrument is pretty accurate. I wish my shop had that.

'95 993

Juha G, I am sure for €60 the emissions probe could be mistakenly placed in the exhaust of the car running next to yours at the emission test centre I believe such things have never ever happened in the UK and such a hypothetical mistake would be so much easier than changine the engine

NineMeister

Yes, low side for on. If I remember correctly the vacuum actuators of the 993nVr and 964 resonance flaps work in the opposite directions, so the safest bet is just to dyno "on", dyno "off" and set the switching state as appropriate.

Due to the height of the linear actuator above the cam tower, the only way we could not dial in the cams using our equipment with the engine in the car is by removing the exhaust re-setting the cam timing from the exhaust valve.I would also In theory this would work fine as we would already have the exhaust timing measurements from the initial build, however I would always prefer to work on the intake valve timing if I could. The rotary actuator is not an easy fit either, would have to change the crank pulley and remove the alternator....

... so yes, we would take the engine out. If I can find a set up photo of the rig I will post it later.

evoderby

Just install nice and soft engine mounts and you won't notice a thing

NineMeister

Not that expensive to buy the raw kit (around $1500 from memory) but you then need to have the capability to engineer the jigs and fixtures to fit the sensors to the engine properly.

NineMeister

Cam sensors on the engine and measurement display. Via a USB link to my laptop, the lift/angle data is recorded through a full 720 degrees rotation of the engine and provides full lift/duration/centreline curves for later analysis. In the report functions velocity, acceleration & jerk of the valve motion is also available.

ClubsportSP

Folks

Appreciate I'm digging up an old thread but wanted to understand how much of a difference the ITBs make to the figures and to the shape of the curves?

I'm contemplating fitting an m84 to my 87 carrera running a 3.4 with DC20 cams, ti retainers, srp valve springs, and ssis fitted, 10.45:1 CR on single plug. Car is for road use only

Thanks all

HiWind

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