Power Fc V's Microtech LTX-12

[Sydneykid]

Hi guys, I just knew that there was going to be some serious head banging over this one. I don't think I can answer all the questions one by one, so I'll try and cover as many as I can in a short post.

Firstly everyone talks about what happens when the air gets hotter, but that's not the problem, as the air gets hotter it gets less dense, the MAP sensor sees pressure not density, so the ecu adds too much fuel for the amount of air. So this is not a dangerous thing, it just costs a few horsepower. But you loose so much due to higher inlet temperatures, the little extra you loose through density gets lost in the wash.

The real problem is when it gets colder than the ECU has been mapped for. You all know the pinging on cold winter nights, that's the real issue. With an AFM you have some chance of the ECU seeing it and correcting for it. A MAP sensor has no chance, so the ECU adds too little fuel and you have a lean mixture. Add that to the colder intake air and you have a recipe for a problem. So you have the need for a air temperature sensor and another correction table and this unnnecessary engine saving fuel enrichment and ignition retarding bandaid.

As I say often, it all depends on how diligent the tuner is. If it is tuned for the operating conditions (all of them) then you don't need the extra complexity and expense.

Hi Roy, I think you may be looking at this in a different way to what I do. We have an R32 GTST with a 625 bhp RB31DET fed by a Garrett duel ceramic ball bearing turbo. We use it on many circuits, short and long. I can assure you I need 625 bhp at Winton just as much as I need 625 bhp at Eastern Creek. We use a Power FC and all I do is alter the boost build ramp (to soften the hit) when it rains, other than that it runs its full 1.5 bar all the time. Eventually I will have to use one of our Motecs with its traction control if I want to go any faster. But a close ratio set of gears will come long before that.

So what Iwould be doing is looking for a turbo that will provide the maximum power that you want but with a decent spread over the useable rpm range. Then carefully select the support sytems to further enhacne this power spread and tune it accordingly. I could tune our engine for over 700 bhp if I wanted to, but it would be far less responsive, way harder to drive, have lower average power and thus would be ultimately slower. You don't need 2 turbos, just get 1 right for your purposes.

Hope that helps some more

[Steve]

SK what boost controller do you use? if it is the power fc boost control, how do you adjust the boost ramp?

[Fitzpatrick Speed Works]

So why is spendin 600+ on bigger afms say for a gtr to change to 80mm z32 items seen as so much more practicle than just putting in a temp sensor for a map drivin ecu??? The way i look at it is: 1650 for a new pfc, then 500 for hand controler, then 600+ for new afms.. when a map based car needs ecu (microtech for example), 1500, 3 bar map sensor 195, temp sensor 78.. I'm not baggin either personally i want the pfc for my car but im tired of the arguement that a temp sensor or sacrificing 5 kw on a really cold nite is such a detramental blow to a map ecu, in hind sight its really no different to having to upgrade afms for more tuning resolution to me thats a downfall too. 67mm x 2 on a gtr is not a restriction it just runs out of tuning ability.

[Targa Tom]

Skyd,

You certainly should charge by the line, this thread alone would get you another holiday on the Gold Coast. And if you factor in by 1.5 for quality info, you could stay there for some time...LOL

Got a PFC for the RB20 last week X Nippon, can it support an EBC, if so what model?

Love your work...

Regards Tom

[Roy]

For what its worth id go a PFc over an LT-12...But horses for courses, or for pulling carts or something????.

Id like to hear from ppl running a LT12/16 about its features though, as my decision is prejudiced from previous experience.

Sydneykid...Yeh it makes sense to have the one turbo, but nothing i do ever makes sense.

Currently the turbo i have on my Rb20 is about as big as i want to go. If i go 3.0L id like to go with a bigger turbo again, so leaves me with a spare turbo. I could sell the old turbo but considering few ppl like Trust turbos, and its only an hours work to swap turbos, i like the idea of going from a turbo setup that gives me an almost NA feeling 250-260rwkws to a more turbo like power delivery and 350-360rwks, with the high mount manifold its so easy to swap

Dont expect others to agree that its a sensible way of going about car mods/ownership, but meh, its my car so...

Even if your thinking isnt as messed up as mine, MAP based aftermarket ECUs do offer extra flexibility and do work well, if like anything they are setup well.

Whilst AFM are great, and i understand the reasons why aftermarket ECUs are predominantly MAP based, you cant deny the simple fact that they can do equal the job, why else do manufacturers like Toyota use MAP based ECUs?

Not saying MAP is better then AFM, just need to be aware of the benefits and drawbacks of each and make an informed decision on what best suits your needs. Id use Autronic SMC if i needed an aftermarket MAP based ECU.

[Sydneykid]

Hi Roy, don't get me wrong we use a lot of Motec's, there are way more of them around here than PFC's. Plug them into the Motec dash and it's race car engineering heaven. The Commondoor had an Autronic, Larry wouldn't fit anything else back then and it was great as well.

But it takes me over half a day to wire up a Motec to a Skyline, then mount a couple of sensors, replace a couple of standard ones so they work with the Motec. Then I have to load the sensor parameters and a set of base maps. Now I can drive the car onto the dyno and start tuning it. With a PFC all this takes 10 minutes. I don't care what anybody says, the owner pays for that 7 hours of extra time somewhere along the way. If it's included in the price of the ECU, then the ECU itself is really worth $400 less than you paid for it, without the installation.

I am sorry, but I don't understand your post "MAP based aftermarket ECU's do offer extra flexibility". Care to elaborate, please?

Hi Tom, Apexi make a Boost Controller Kit for Power FC's we also use the Autospeed designed Norgren valve based system.

Hi S13drifter, GTR's come standard with inlet an air temperature sensor, it's on the plenum. The advantage of PFC's, for me anyway, is they simply plug in and everything works. I don't have to fit anything else, no wires, no pipes, no plugs, nothing just plug the ECU in. Plus I don't have to tune the cold start, or the idle stability for air con, power steer or electrical load. All I have to do is tune it for power on the dyno and that's easy.

Let me ask you this, how would you go about tuning a car for cold start and run? The car is only truly cold once per day, in the morning. So I have to tune all the parameters for cold start and run in under 5 minutes. Because that's all the time you have got, the engine is hot by then. If it doesn't run well, then you wait until tomorrow morning to try it. What if it's summer time, do I tell the owner to bring back in winter, leave it overnight and I'll tune the really cold start and run for you?

Tuning an ECU for power is piss easy compared to all the other stuff you have to do to make the car nice to drive, so it doesn't stall when it's cold, so it handles the air con on 40 degree days, so it starts when its 0 degrees etc etc. You can't do any of that on the dyno, any time you want, like you can for power.

With a PFC you get all that pre programmed and the car runs just as nice as it did with the standard ECU. I have seen plenty of highly modified cars that make good power, but not very many that run nice. Why? Because it is damn hard and very costly to tune all the necessary parameters from scratch.

Hope that all makes sense

[Ryno]

You guys are all looking into this Map vs AFM discusion far too complicated... Hopefully I can dumb it down for you.

An Air flow meter, effectively measures the amount of air particles travelling past it at any given time. Therefore the computer supplies "x" amount of fuel, in a direct proportion to the amount of air particles... Sweet

A Map sersor purely measures the preasure of those air particles (not actually how many air particles are there) and supplies fuel in proportion to air pressure. This is a problem (as has been stated before) because it doesn't account for temperature.

If your climate doesn't vary that much, it's not a big problem... However as an example, if your tune was done in ISA conditions (+15 degrees at sea level, air pressure 1013 hPa), and you're driving now on a 40 degree day (with the same air pressure of 1013hPa) you'll be running slighly rich as the density altitude is 3000 feet, and not at sea level (which is what your computer, thinks it is).

[Roy]

I am sorry, but I don't understand your post "MAP based aftermarket ECU's do offer extra flexibility".  Care to elaborate, please?

Take the Autronic, you can upgrade the SMC/SM2 comes standard with user selectable parameters for things like oil temp, water temp, air temp, boost pressure. To some this may not be that big a deal, but im not experienced enough to monitor these during club motorsport, nor am i interested in filling my interior with gauges, so if oil temp gets too high, or a wastegate hose blows off, the computer detects a paramater being exceeded and defaults to "limp home", whereby protecting my engine.

The SMC has 8 injector outputs, and as they are independent you can use 6 to run your engine with sequential fuel injection, whilst using the spare 2 injector outputs for things like a intercooler/radiator water spray, boost control, anything really as you have spare outputs. Do you really need them, maybe not...but it adds to the flexibility of the ECU.

Also cant remember exactly but it has data logging for somehting like 15 channels, storing 30kB odd which is uprgradeable. Not sure if is both the SMC or just the SM2 but can measure and compensate for back pressure on turbo cars...just how many ppl buy these fancy ECUs and use the features is another story...me because im a frustrated car owner who wishes my road car wa a race car i like playing with these features :Oops:

Also i havent heard too many tuners that would prefer to use a handset over PC for bulk of the tuning, and i dont believe the software is available for all PFcs yet. Autronics can be upgraded with 'Auto tune' feature...just more features which add to the flexibility of the ECU.

I strongly agree with what you are saying about the day to day driving with aftermarket ECUS - tune wise, it took a long while to get my old MT8 running nice. Actually that and a friends 200SX are the only cars i have ever been in where you cant pick that aftermarket injection is being used. Stallin during u-turns, air con on whislt turning the power steering= stall etc etc

[Freebaggin]

Hi Guys, let me throw this one at you.  Power FC's use AFM's and when the air temperature rises the air density decreases.  The AFM senses this lower density and the ECU compensates for it..........

False logic maybe.

If the AFM senses a lower density due to hotter air, then it will deliver LESS fuel for the same throttle position. So you are effectively saying for PFC if the air temp rises your fuel mix will correspondingly become LEANER. If this is the case, it's OK for Nissan to have this situation as the A/F mix is SO rich anyway there is plenty of room to move.

Liek Roy said, why do one of the best engine series not use AFMs and use MAP sensors instead....that is the 1JZ and 2JZ series....I don't know why but an interesting point.

Look, I'm not saying AFM are worse, I just think it's much of a muchness between the two but I have heard from one or two tuners that one of the PFC's weaknesses is the lack of temp compensation. Otherwise a good ECU.

[Ryno]

False logic maybe.  

If the AFM senses a lower density due to hotter air, then it will deliver LESS fuel for the same throttle position.  So you are effectively saying for PFC if the air temp rises your fuel mix will correspondingly become LEANER.

You're wrong about this dude, if the temp of the air is hotter for the same given pressure it IS less dense, and WILL require less fuel to stay at the same air fuel ratio. The Air flow meter is correctly sensing the change in Density, and fueling correctly to compensate.

With a MAP sensor (if there is no assosiated temp sensor) it cannot make this correction.

[Freebaggin]

You're wrong about this dude, if the temp of the air is hotter for the same given pressure it IS less dense, and WILL require less fuel to stay at the same air fuel ratio. The Air flow meter is correctly sensing the change in Density, and fueling correctly to compensate.  

With a MAP sensor (if there is no assosiated temp sensor) it cannot make this correction.

I am not entirely wrong ... dude. I basically said the same thing that you have just said.

Maybe better explained with two scenarios:

1bar boost at 5°C

1bar boost at 50°C (as would be seen in circuit racing)

AFM ECU - fueling different for each situation to give same A/F ratio (dangerous maybe??? and no way to change other than with across the board richening up to cater for hot situation)

MAP ECU no t. comp. - fueling same for each. Hotter situation would have richer A/F ratio as ACTUAL density is lower but fuel same (inherently safer????)

MAP ECU with t. comp. - fueling different for each situation but entirely tunable (if you are ever able to tune across that temp. range)

[Sydneykid]

Hi roy, firstly let me apologise for being pedantic.

You said "MAP based aftermarket ECU's do offer extra flexibility". Then you proceeded to justify this by using the example of a $5,500 Autronic (that's what it costs with all the software enabled and the necessary hardware that you used in your examples). If you had said "a fully equipped Autronic offers extra flexibility" then I would have had no argument. But you posted it like it was for ALL map based ecu's, and that is simply not true. Many map based ecus don't offer anywhere near the number of features of a Power FC.

Just to clear up it up further, there is very little that you have listed that we can't do on the GTR with the PowerFC and the Datalogit system. We run an intercooler spray, the PFC has a boost controller kit, it has 6 injector drivers and 6 ignition drivers. Dash warning is configurable for the problems you have listed, which we find much better than simply shutting down the engine. As for the Autronic having 30kb of memory, is that all, with the laptop plugged into the Datalogit we have 100gb of storage.

Now if you offered me the choice of a free Autronic or a free Power FC, then I would take the Autronic every time, they are a great motorsport ECU. But when the all up (tuned) price is more than triple, that's not the same question, is it? For the same money I would take the Power FC, Datalogit with a Pi System 1 and a Cdash.

Roy, please take this the right way, what I am saying is, there is more than one way to achieve what you want. I strongly suggest that you look at all the options, add up the costs of the various items and the alternatives and then make a educated choice.

In closing, I better own up, I can't self tune with the Datalogit and the Power FC, we do record A/F ratios on the Datalogit using a F&W lambda sensor. I have to then manually tune it, but even John at Autronic will tell you that the self tune can be improved upon by manual tuning anyway.

I apologise if this post takes the thread too far way from its subject.

[Roy]

I did say offer more flexibility, didnt say at what price.

Though the SMC i was looking at was just under 3k installed and tuned, and it had all the outputs required to run the car as per std ECU, plus a few left over. It was password protected to stop me form butchering the tune ( :Oops: no faith :Oops: ), and at any stage i was able to upgrade the ECU or remove and take it with me for my next car.(perhaps the best feature)

Considering this was the price from the same guy that managed to get my MT8 running the way it did, i have no problem in believing that the SMC would have driven like a dream once installed and tuned. Plus for a fairly std car, they have so much experience with these ECUs they can get the tune 90% right using previous experience/tunes.

Thats why im interested to hear what the LT12/16 are capable off, if the LT16 is truly a big leap forward then id perhaps be interested in giving one a go.

I look at some aftermarket ECUs and i dont believe they should be used as a stand alone ECU, perhaps better suited to piggyback...does saving those few dollars initially cost you money in the end?

I agree the PFc is a good thing, but for RB20s they perhaps dont represent the initial bargain they do on GTRs, R33 GTSts etc, usually some $800 more when they can be found, and thats getting up around $2500 tuned + AFM upgrade if req'd. The what does the datalogit software cost when it is available for a PFc?

R33 GTST , since you can Power Fcs intalled, tuned using bigger AFMs for well under 2k then they do take some beating. So we need someone to go to bat for the LT12/16s and list all their features and how they go on their cars.

Sorry for being long winded, and not saying anyone is right or wrong, just adding my thoughts...oh and ill take Pi System 1 and a Cdash please

[Boosted Zed]

I have read briefly through this long involved back and forth and appoligise if I double up on things already covered.

Firstly we sell and recommend both Pwr FC and Microtech for different reasons and cater for customer’s preference. If I had a GTS-T though and was a performance road car I would go the Microtech. If not a plug in as both now are it would be a different story.

A couple of things there has been some talk of AFM and calibrating according to air density and flow to adjust for hot days etc. In theory this happens but in reality it DOES not adjust enough. We have tuned plenty of cars with P FC on a cool day and no probs and first hot day that comes along they can ping, so we have to tune them for a hot day basically so on cold days guess what? They don't have as much power as a Microtech.

Microtech has more options such as head up display which is like R34 GTR as in t presets on boost, revs, inlet temp etc and it gives display and flashes to warn you.

The new option with Pwr FC by the way DJetro does away with AFM as does the new Tomei Reytec that also has a great feature where you can download base settings for certain cars and features which can save a lot of time.

Microtech are easier to tune and data log and more functions such as cam advance adjustment etc and from our experience Microtech are more reliable. As Roy mentioned I think they have come a long way and Microtech especially with their new model and fine settings of injector drivers etc will be up there in a way with Autronic and Motec for much less cost. Autronic and Motec however have a automatic built in equasion or algerythim that works out manifold pressure and inlet temp and ajust timing accordingly and possibly fuel although not sure on this. They are a bit better in this way but cost heaps more and not plug in.

Another point is the inlet temp as sensed by AFM and volume of oxygen molecules is one thing, but then it goes through a turbo and intercooler of various sizes and efficiency so it is more important to measure manifold pressure and temps?

As mentioned Microtech are cheaper when considering having to upgrade to 300ZX AFM.

The Pwr FC has good points to though such as the nock sensor ( reminder that it is not coping with hot day ) and integrates with factory dash lights etc and if you have hand controller read outs and knock meter etc I would rather have a mounted nice dash display though.

Regards

http://www.tomei-p.co.jp/_2003web-catalogu.../efr_index.html

[Ustasa]

Ryno,

You are correct for the fuel side, however the AFM also dictates what ignition timing the engine will receive at its operating point. The a/f ratio might be fine but the ignition advance will be greater in hotter (lower density hence lower load reading) conditions. This is exactly what you don’t want. Hence the reason why many tuners malign the lack of air inlet temp correction on Power FC’s. Funny how the GT-R has a air temp sensor mounted on the plenum yet it is air flow metered..hmmm

[Sydneykid]

Hi guys, I have resisted this far, but I can't do it any more. I have 2 things to say about Microtech;

1. Cheap and nasty throttle angle sensor as supplied with the LTX12, failed, ECU read throttle closed and decreased fuel supply. No error displayed, despite rpm at 9,000 and a MAP sensor reading appropriately (zero pressure because the throttle was wide open). Result = extreme lean mixture, no apex seals and a $6K 13B down the drain. If this had happened with a Power FC, the AFM would have known the air flow and calibrated the fuel supply accordingly. So I am having real trouble agreeing with the post "Microtech are more reliable".

2. Microtech is an ECU company supposedly at the forefront of computer controlled engine management, how about we try a visit to their web site......

www.microtechefi.com

Let's look up the specification of an LTX12, hmmmm can't seem to find any. Dig around for a while and you can find some general details on LT's though;

"16 bit interpolation between the 256 load sites on the main fuel map"

What only 16 bit and 256 load sites? What happened to 32 bit and 400 load sites. That seems to be totally contrary to the post "They don't have as much power as a Microtech".

Last comment on recent posts;

“it goes through a turbo and intercooler of various sizes and efficiency so it is more important to measure manifold pressure and temps".

I am I really expected to believe that if I change my turbo and intercooler that a Microtech will adjust the tuning accordingly? Wow, that would be something!

I will bet you that an AFM equipped car will handle a turbo upgrade and an intercooler change far better than a MAP and Inlet Air Temp equipped car. Why? Because a MAP and IAT equipped car has no idea how much air the engine is getting feed. It knows what pressure it is and it knows how hot it is, but is has no flaming idea how much air is going in and thus how much fuel to add.

My experience is, due to inefficiencies in the engine, not all the air makes it into the combustion process. Thus the AFM equipped car will run rich. This is much safer than the MAP and IAT equipped car with a turbo that flows more air at the same boost, which will run lean. I know which I would much rather have. You want proof, well take a look at the modified Skylines, bigger turbo and FMIC still running on the standard ECU with an AFM. Wouldn't happen with a MAP sensor based ECU.

I’ll accept an argument as to why I should buy a Microtech, as long as it is backed up by facts. But I simply haven’t found any yet.

[Sydneykid]

Hi Ustasa, my post from 4.20 pm yesterday "GTR's come standard with inlet an air temperature sensor, it's on the plenum."

[Steve]

This is almost starting to sound like a holden vs ford thread:)

[Sydneykid]

No pushrods here Steve.

[Roy]

No pushrods here Steve.

meh...pushrods, anyone tried running a 1050 Dominator with a draw thru turbo setup, forget injection, real men use big carbs