ORIGINAL: John Sims
I have been discussing this issue with Rick, who has gone the MAF route (or at least will when he gets the bits) in prefferance to MAP. Apparently, he had a few chummies who totaled Cossies in the past trying out new kit and is consequently sticking with tried yank practice. If, as I'm assuming above, Andrew's kit is just a Danno import then we shouldn't end up as Beta testers and this shouldn't be an issue.
Nearly, john, but not quite. [
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I'm not going MAF at all, just MAP (and it's not yank practice either). The main advatages to MAP upgrade include being able to free up the inlet tract (atmosphere to turbo) and fast response time.
The 951 AFM is a very crude, slow and restrictive device. At one extreme, it severely hampers throttle response by the restriction to change of air flow rate by means of the spring loaded barn door. At the other, it severely limits mass air flow at high RPM by it's (necessarily) small orifice. Getting rid of the afm leads to much better throttle response (therefore driveability) and allows much better air flow.
Perhaps one of the best descriptions can be found on Danno's site.
Here
With this restriction gone, a larger turbo, better intercooler and other changes to the inlet tracts such as air filter, smoother air path up to the throttle body etc the amount of airflow available to the engine increases significantly. An efficient cold air inlet and intercooler (and larger turbo compressor) also allow much greater density of that (increased) air volume. Air flow = power (so to speak).
I've already got a free flowing (non restricted) 3" straight through exhaust and a reasonable sized (#8) hotside on the turbo to get the gasses out.
To get the gasses in, I've got a Lindsey Racing stage II Intercooler. Currently the biggest restriction on my engine is the AFM. Once this is gone, I can change to a K27/8 or maybe T04E. I'm looking for a spare 8v head and inlet manifold at the moment to modify up and blend the ports etc.
It makes sense to me to change the head / manifold / turbo in one session, and clean up a whole lot of pipework under the inlet manifold at the same time. Probably with aeroquip. Possibly also look to add a catch tank to catch any oil displacement from blow-by when the boost goes up.
The DME is not the brightest of engine management systems and does need a lot of signal massage to cope with a MAP sensor. Although the link does a very good job at dealing with the fuelling translation, I think I'll probably end up with a standalone management system at some time in the future to allow more flexible mapping.
When I first got my 951 and decided it needed some serious tuning attention, and saw how the management system / AFM was set up, one of my first thoughts was to ditch the standard AFM and adapt a map sensor and signal massager as a first stage of tuning ! Time passed and the Americans started bringing out kits to do that 'off the shelf', rather than me bothering to do the fabrication of the revised intake etc. I've been waiting since mid last year for Danno's bits to arrive !
It's true that no 'one size fits all' option exists when it comes to mapping a car. No matter how many 'hardware' modifications you make to the engine, ultimately it's in the hands of the man who does the final mapping to bring it all together. This holds true both for getting the required power / torque charicteristics, and building in the safeguard limits such as rev / boost / retard to keep it all in check.
While Danno's maps are reckoned to be exceptionally good, once you move outside the parameters that the mapping is based on (change induction / exhaust / cam etc) then those maps can only be relied on as a start point. With the GURU map kit, I can map the fuelling from in the car is moving. I already have electronic boost control of a dual port wastegate. Currently ignition mapping is a 'chips out / emulate / remap / burn / chips back in) process which is restrictive if you constantly want to change your engines specification.
I suppose it all depends on how far you want to go, how much you want (can) to tune yourself and how much time, money and effort that you want to spend.
A known, tried and tested solution such as Danno / Guru is never really going to get you in to trouble. His matched kits are complete packages working as a matched set of components. Being able to buy them through Andrew Sweetingham makes it easier for us in the UK, and provides the necessary support if you need it.
To go up to the wilder state of tune such as Andrews race car that's using (relatively new to 951 but been around for years and expertly refined in cars such as Cosworths) MAP technology, needs the backing of technical tuners with a proven track record, such as Wayne, to make sure that the necessary safeguards are programmed in.
For my part, I enjoy the development cycle, in this case turning my 250 BHP start point in to something that I enjoy driving and has much more performance on tap. The only problem is, once you start on one of these trips, it never ends !
Development starts on the rolling dyno and ultimately gets tweaked on the open (private ?) roads where the affects of airflow are different to a static dyno.
There is always something that you are refining (or ripping up and replacing) in persuit of the unattainable - perfection. It's a bit like those who prefer to keep their cars ULTRA standard and compete in Concourse events - they always find another screw head to align or a new orifice to get at with a q-tip (LMFARO).
At the end of the day, you pays your money and takes your choice !
(I'll go away for another couple of months again now LOL)
Edited - just to tidy up the boxes [
] Paul