Gordon951

Doug-

Where did you end up putting the IAT sensor? I'm installing MS3 in my 951 as well. I'm considering threading it into the outlet section of the intercooler.

Dougs951S

It really needs to be in the post IC pipe as close as possible to the throttle blade. The air will heat up between the intercooler and the throttle and you need an accurate air temp.

Gordon951

Ok. I wasn't sure if that was going to be enough of a factor. I'll put it as close to the throttle as possible. Maybe in the boot going between the hard pipe and the Throttle Body.

Do you have any engine bay pictures? I'm looking for ideas for my turbo inlet piping and where to mount my LS coils. Thanks!

Will Feather

Doug, are you using the MS3?

Dougs951S

Nope, I'm running a microsquirt v3 which is a surcace mount version of the Ms2 hardware. Running the latest ms2 extra code.

azbanks

I've got the DIYPNP. I bought a soldering kit yesterday and tried my hand at soldering it.

I need a few more kits to get the skill down.

Brentb1

What is the approximate cost of the unit itself along with the needed sensors? I am 100% having standalone and found this thread to be very helpful. Thanks!

Dougs951S

The USquirt unit + 8' harness (which will need to be shortened in places and spliced into the factory harness) is about 375 dollars, you can find them cheaper used. The sensors can cost anywhere from a lot to a little, depending if you buy new or go junkyard digging (which I recommend since they're dime-a-dozen GM sensors). I think in total I spent less than 10 bucks for sensors. You'll also need a trigger wheel, there is a company I mentioned earlier that makes a bolt on unit for a good price. You can definitely do a decent microsquirt swap with some nice features like wasted spark for under 800 bucks all in (thats coils, injectors, tuning software ect), it just depends how much stuff you already have on the shelf and how far you want to stray from the factory hardware setup (since you can really set the car up however you want now). Things get a lot more expensive if you want to keep A/C or power steering, unless you're good at fab. A full bells and whistles microsquirt setup on a street 951 with sequential spark and fuel, electronic boost control, active knock sensing, ect is going to probably be well over 1400 most likely (the fancy cam pickups available are $$$ unless you rig one up yourself).


Beyond that, its just wiring, installation, and then a year of tuning. I'm still fiddling with mine once in awhile, many months and many thousands of miles later, because I'm finding as the weather is getting colder it still needs some fine tuning.

techartisan

What are the advantages/disadvantages to going megasquirt over something like Josh's (roguetuning) kit?

Dougs951S

I cant really answer about whether of not stand alone is better than a MAF kit. What I will say is, I dont get paid what-so-ever if anyone here decides to go stand alone. I am not selling anything. I am just cheerleading for a product that I really like. It is up to everyone here to read up and decide if MAF is right for them or stand alone. Installing and tuning a stand alone is a lot more work than buying a complete MAF kit, there is no question. Is it better? I definitely think so

I've been discussing with a good friend of mine about megasquirting his NA car, which presents some slightly different issues vs a 951 install. I'll go ahead and expound on the things that I told him. In addition to everything I've covered in this thread, I will also relate a note about fuel injectors. MS is capable of driving either low or high impedance injectors, but it can only drive 1 low impedance injector for each of its two channels, meaning that it would really only work on a 2 cylinder bike engine or something similar. It is however, capable of driving up to 4 low impedance injectors per channel for a total of 8. There are a large number of OEM injectors available cheap that will fit the bill for an NA car. The only requirements are that they use an EV1 style electrical connector and have a minimum of 10 ohms resistance, as well as at least 26 lb/hr flow rate at 3 bar fuel pressure. Good ones that come to mind are ls1/ls2/ls6/ls3 injectors and injectors from either a ford or GM supercharged V6. They can be had for well under 100 bucks for a set.

All wideband o2 kits will thread into the standard bung already being used by your stock o2 sensor, but you'll need to install a new bung anyway. The stock location is under too much heat and pressure for a wideband sensor to survive long, it must be placed a minimum of 36" from the turbine outlet (on an N/A car, the stock location is fine). The AEM and innovate MXT kits are both good, you don't really need to spend more than 150 on a kit.

I stated earlier you will need to ditch the stock TPS on an NA car, but the 951 TPS is pricey. Its cheaper and in my opinion, better to get an adapter plate to bolt on a standard GM TPS to the 944 throttle body. They are 25 dollars here >>>> http://www.ebay.com/itm/Porsche-944-...3D321568328337

So to sum it all up, no, going stand alone is NOT cheaper than getting a MAF kit for an NA car. There are benefits, its up to you to decide if stand alone is right for you. Here is a basic cost breakdown.


microsquirt unit with short 30" harness: 350
Fuel injectors: 75-100
wideband o2: 150
trigger wheel: 40
tuning software + cable: 75
TPS adapter plate: 25
ignition coils, sensors, wiring, misc BS: ???

You're already at 750+ and if you dont get lucky finding the sensors at a junkyard, expect to pay ~80 bucks for a new TPS, MAP, and IAT sensor with pigtails and another ~100 for coils. You'll also need GM spark plug wires. Add in a bit more if you need to purchase a dead DME to use as a harness adapter. That's why its good to budget 900-950 for the completed project. Its definitely possible to do it for way less, but it shouldnt cost you more than that unless you decide to go full sequential or buy an aftermarket trigger wheel sensor bracket. Other things like choice of ignition coil, wideband kit, and fuel injector choice can also push the cost of this project past 1k all in.

odonnell

Doug has been walking me through the process of squirting my car, and I'm completely on board with it as soon as room in the budget appears. I really like Josh's MAF kit, don't get me wrong, but the beauty of MS is that you can use whatever hardware you want. The MAF kits currently on the market definitely introduce better hardware and a sweet tune, but still stands on the shoulders of the aging DME, harness, and other sensors. MS allows you to remove all the aging circuit elements and oxidizing wiring/solder joints/PCB from the equation.

In my opinion, it's the largest single factor toward making a 944 a reliable and usable car like it was when it was new. Most of the classic 944 problems can be shut down (cough cough no starts). Plus, you pay once and now you can use GM sensors and whatever else you want. No more P-tax on Bosch engine bay stuff.

Dougs951S

Michael and I have also been discussing improvements to this guide, I tried to be clear and concise but the learning curve is super steep with MS and I'm sure some things that make perfect sense to me are a little murky. Speaking with Michael about this has renewed my interest in making the community aware that going standalone is something that's really attainable, not super expensive, and a realistic option even for a stock N/A car. In the coming day's I'll be expanding and modifying this guide, I'll need a mod most likely to reorganize my posts since I'm going to tack on some additional posts here. Thanks everyone for reading, this guide is the culmination of a year of intense learning and I'm excited to share what I know. Since finishing my car, I've had the opportunity to setup and tune several different makes of car running megesquirt. My appreciation for the miracle of modern fuel injection has risen 10x compared to this time last year. Cheers everyone.

azbanks

Thanks for pioneering this option for us. My parts are slowly coming together for my MS project.

Dougs951S

Idle control, or "why does my idle suck?"

Adding this section in because the subject of idle quality has been a point of discussion lately between a good friend of mine and myself. Be forwarned, this section is full of personal opinion.

1: You don't need an idle valve of any kind to have a good idle..SO LONG AS YOU LIVE SOMEPLACE WARM!.

I live in Texas, and despite what people thing, it does get below freezing here. My car still fires up in the morning on the first bump of the starter and idles without me needing to give it gas. My idle screw is all the way shut and sealed with an O ring so that no air can bypass the throttle blade. How is this possible? The secret is that the factory idle is a compromise between lots of things, but its far from the best, most stable idle the 944 engine is capable of. Forget trying to idle at 14.7:1. Batch fire engines, especially ones with large bores, suffer from intake pulse reversion which cause some cylinders to fun leaner than your wideband is telling you. You won't get a 944 engine idling well at stoichiometric, no matter how much you think it should. Peak torque is made somewhat rich, between 12.2:1 and 12.5:1. I shoot for a bit leaner than that, around 13:1 to 13.2:1. Why? Because if I idle the motor at its absolute best idle setting, I can not get it to idle below 1100 rpm because it is idling so efficiently. In addition, a stock car idles with ~5* of ignition timing. Doubling that is a good way to give the motor more off idle torque. Don't try this at home if you have a catalytic converter, the extra ignition advance wont hurt anything but the cat wont like idling rich. That being said, if you dont have a cat, you probably won't need any form of idle control.

You have a couple options though if you find you do need idle control if say, you live in the north pole, or you have AC, or something like that. The easiest is finding an electric binary on/off idle valve of the non-stepper type. This is basically a valve which acts as a controlled vacuum leak, being either completely open or completely closed. Because we are tuned speed density, it doesnt matter at all where this valve is placed or where it draws its air from. A valve big enough to raise the idle 250-300 rpm on a cold engine is about right. You can set this type of valve up one of two ways, either by wiring it directly to an on/off toggle switch and using it like an electronic choke, or wiring it into MS and letting it control it via a temperature parameter.

The other, more sophisticated way of implementing idle control is via a PWM stepper motor just like the factory did. I wont go into too much detail here other than to say that this is a totally acceptable thing to do, and you have a wide range of PWM valves to pick from. MS has a few different control algorithms available, but generally you'll want to set it up to target a specific RPM so that on a cold start, it will keep the motor happy and then basically do nothing once the engine is up to temp.

zermattsilver

+1; sausagehacker is 100% correct stating Megasquirt is THE answer to multitudes of issues. The benefits, to implementing Josh's (rogue-tuning) kit, are minimal and the kit is grossly overpriced. Moreover, Josh's kit does not address an antiquated DME/engine sensors and deteriorating wiring harness. Putting $500ish towards a DIY Megasquirt project will yield a great payoff; rock solid engine management integrity, plus a significant increase in gas millage.