Mappable ECU's - The definitive thread

[SimonN]

So $ per hp. That's a really interesting question! I only have some figures. On a 964, going from AFM to MAF and chip with cup pipe and decat is something like $3000 and gives you around 50 bhp plus a great shaped curve and a wonderful sound. That makes it $60 per bhp. That's the "low hanging fruit". To get to, say, 320 bhp (+70) without opening up the engine, through the Motec route, is offered in the UK fitted and mapped for $7000  which works out at $100 per bhp. I am trying to get comparable figures for a 3.2. Where it all gets interesting is when you have a modified engine and you compare carbs such as PMO's against aftermarket ECU's. There I believe that you are looking at very similar pricing, but you get a better bang for your buck with the EFI. However, that assumes you can map it or get somebody else to do it for you. If there is nobody around, carbs are the easy option.

Boosted cars are so much easier to get power out of, although they are also a lot easier to blow up if you do it wrong!

[Redracn]

The cluch is also the mechanical fuse. 

[smit2100]

To get this thread back on topic; I firmly believe that while the motornic as fitted to 993 and earlier cars are too damn old to do a lot with.

Having said that, there are a few things that can be done as pointed out by Simon and others.  A change in the intake, exhaust or minor valve lift increases (camshaft replacement with a mild cam) all necessitate tweaking the fuel and ignition maps for both engine longevity and releasing performance gains.  The problem being that the tech is just too old. Relying on a MAF - which by its very nature is a restriction in the intake - won't see the best from an engine.  Nor will the lack of knock sensors or oxygen sensors (depending on what model we are talking about).

What you have to ask yourself is what you want from your car.  Do you have a random power target? Do you simply want it to be nice to drive and start every time no matter the weather?  Do you want maximum performance?

it's also worth noting too much focus is often on peak power.  Peak power is great for winning dyno days or the morning coffee circle-jerk. Optimum engine performance is far more complicated than that.  What we really need to consider is the "area under the curve" of the torque and power curves.  A long delay until the upper end of the rev range before a massive ramp up (ala early 930) to peak power won't get a car around a track as quick as one tuned to have power come on early, smoothly and consistently to a long plateau (ala  993) even if the maximum value is lower than the previous example. Also makes it a complete bastard to drive in traffic compared to a something with smooth delivery of power.

 

Examples: 930 stupidly steep ramp up. This is why lots of people used to go backwards through hedges.

GT4's much smoother ramp

http://cimg0.ibsrv.net/gimg/rennlist.com-vbulletin/800x638/80-f81107da4b9ebb84_4a72404abfdc513677413f476c0455d45e2a7c23.jpg

 

Drag racing, circuit racing, hillclimb, rally and oval track all demand different power and torque delivery characteristics. So do road cars for that matter.

A mappable ECU will allow a tuner to fix some basic corrections after minor mods, but if you start doing significant modification (I'm looking at you, turbo guys) then the stock stuff won't cut it, with only a few exceptions.  Delco has been hacked to death and is one of the few stock ECUs that can do a heck of a lot. Of all the cheap ECU options it's a good one to consider for a retrofit.

Stock ECUs generally won't allow for changes to inputs and outputs. The ECU can control more than fuel and spark. It can be used to switch cooling fans on and off, warning lights, turbo timers, and so on. 

 

 

In short; getting the stock ecu adjusted for minor changes is a good thing to do and achievable but for an engine that is to undergo more than an exhaust and throttle body change I'd suggest going aftermarket ECU in some way.

 

 

 

Great post.  As I see it, you hit a big nail on the head when it comes to tuning ECU's in general which doesn't get enough airplay.  Whats you goal / use of the car/ and too much focus on peak numbers.

+5 on area under the curve vs peak numbers.  Is that dyno of a 930 (not boosted) and at the crank numbers.  Impressive gradiant on that curve eg 300ftlb over 1500 rpms from 3500rpm e.g gradient of about 0.2.

+5 on want that curve nice and steep and a long tail. eg But I;m more partial to something that starts delivering in down in the 2000's not 3000's and something like the curve below is more ideal for overall driveability (eg usable power and torque from 2000 to 4500).That said, the scale seems a bit deceiving on that 930 dyno and is it really that impressive in terms of steepness. Wouldn't say it is stupidly steep.   For instance, the curve in the dyno below has a equal gradient (much steeper if your dyno is not at the wheels)  eg 0.2 gradient  as well from 3000 rpm to 4500 if talking at the wheels,  but doesn't look anywhere near as steep as your curve. 

[SimonN]

Comparing those 2 dyno plots is totally misleading and you cannot comment on the shape or steepness of the curve from them. Why? Because the scales are so different. I personally think that single dyno plots are pretty pointless, because you need something to compare a plot against. Sometimes, a comparison against standard is what is all that is needed but sometimes, you need 3 or 4 plots together to tell the story properly.

[smit2100]

Comparing those 2 dyno plots is totally misleading and you cannot comment on the shape or steepness of the curve from them. Why? Because the scales are so different. I personally think that single dyno plots are pretty pointless, because you need something to compare a plot against. Sometimes, a comparison against standard is what is all that is needed but sometimes, you need 3 or 4 plots together to tell the story properly.

But isn't scale the first thing you look at when comparing dyno's.    Eg first, get the y axis baseline sorted, eg we talking crank vs at the wheels ).  Then I thought my year 7 maths (why I noted 0.2) at least sorted out the steepness of curve out regardless of scale which I do like to compare. eg In general terms  besides nominal peak numbers, I like to see how smooth the curves are up to peak numbers, where peak torque and power is being made in the rpm range ( I prefer curve being left centric as opposed to being right centric), the difference in rpms when peak  power and torque is made and the rate (gradient of the curve up to peak torque / power numbers) at which those peak numbers are achieved.

Notwithstanding you can see material differences in dyno results, particularly peak numbers from different dyno brands (eg mustang vs mainline vs dyno dynamics) , operators and dyno hut conditions eg fans or no fans etc  (why I prefer to have tunes dialled in using road logs based on actual driving conditions) I still reckon the area under the curves (torque and power) allows you to make some general comparisons and gives some insight into the performance / driveabilty of the car.

But I'd rather look at some dyno's irrespective of the scale, rather than a couple of peak numbers.  Throw in some times, 0 to 100km/hr times, , fats times and trap speeds and reckon their even better story tellers..  But still reckon the best indication is whether your tuned ecu passes  you butt dyno sniff test

In sticking with the theme of numbers / data, in terms tuning the stock aircooled ecu, does a durametric generally give the tuner enough logging data to dial in a tune or do the goto tuners have their own logging software / module to plug into the obd2 port 

Also in terms of exhaust mods, when you say decat, is there a goto fabbed setup from a goto vendor , or can you do a homebrew job and gutt the stock cat material (keeping a stock set just in case (db issue as opposed to unlucky sniff test issue)

[SimonN]

In doing some research, I came across these people and thought their set up looked worthy of further investigation

http://rasantproducts.com/porsche-engine-management-kits/

In short, they produce what seems like plug and play kits which include all the tricky stuff such as wiring. It is based on  the AEM Infinity ECU which is mapped using VE (volumetric efficiency). Reading up on the ECU, it seems very easy to set up. What i don't know about is how it compares with alternatives, but I am always looking for the easiest way of doing things, so a complete kit sounds very attractive. I will be doing some more reading in due course.

[Mike D'Silva]

So $ per hp. That's a really interesting question! I only have some figures. On a 964, going from AFM to MAF and chip with cup pipe and decat is something like $3000 and gives you around 50 bhp plus a great shaped curve and a wonderful sound. That makes it $60 per bhp. That's the "low hanging fruit". To get to, say, 320 bhp (+70) without opening up the engine, through the Motec route, is offered in the UK fitted and mapped for $7000  which works out at $100 per bhp. I am trying to get comparable figures for a 3.2. Where it all gets interesting is when you have a modified engine and you compare carbs such as PMO's against aftermarket ECU's. There I believe that you are looking at very similar pricing, but you get a better bang for your buck with the EFI. However, that assumes you can map it or get somebody else to do it for you. If there is nobody around, carbs are the easy option.

Boosted cars are so much easier to get power out of, although they are also a lot easier to blow up if you do it wrong!

I have a freshly built motor, decat and cup pipe. Just bought a SW chip but now I want to know how to get that 50hp!!

 

[81SC]

In doing some research, I came across these people and thought their set up looked worthy of further investigation

http://rasantproducts.com/porsche-engine-management-kits/

In short, they produce what seems like plug and play kits which include all the tricky stuff such as wiring. It is based on  the AEM Infinity ECU which is mapped using VE (volumetric efficiency). Reading up on the ECU, it seems very easy to set up. What i don't know about is how it compares with alternatives, but I am always looking for the easiest way of doing things, so a complete kit sounds very attractive. I will be doing some more reading in due course.

There is some good information on this Pelican thread, regarding the AEM Infinity install.

http://forums.pelicanparts.com/porsche-911-technical-forum/932541-triumph-itb-aem-infinity-project.html

[Tit]

Singer uses AEM.

They also use them in the Speed Academy 930 build...