After Some Mafless Ecu Options

[Finny]

Hi all,

I have been researching ECU options for the last 6 months and I still find my self back at square one with no real options.

I have an RB30DET forged internals, high end cams, big turbo, 800cc injectors, big fuel pump etc. etc.

I disconected my actuator so in high revs I am seeing about 3psi. I have a STOCK ECU with only a SAFC to adjust fuel mixtures so that I can sneek the car about untill I get complete A/M management. My cams seem to make all their power between 5,000 - 7,000rpm but at 5500rpm on 3psi of boost I am maxing my Air Flow Meter.....

After thinking about this I thought well a Q45 AFM can still be maxed out with out too much effort so I would really like to go a MAFless tune.

I have been studying these two options at the moment, One being a Microtech LTX12 and an E-manage ultimate.

These both can run with a pressure sensor but ofcourse E-manage untimate is a piggy back system but also this is a street car so weighing up the power possibilities of the Microtech and the drivability of the E-Manage and I am just stuck there.

PowerFCs are way too old for my liking, every one has them and they can't run a pressure sensor, they are also way too expensive for what they are. eg. $1600 for an RB25.

The other thing that is really opealing about the E-manage Ultimate is I will be able to slap my car on dyno and tune it my self with a laptop. I will also most likley be able to do this with the Microtech aswell, I have had a play around with the software. I live in Tasmania and the tuners here are well.... hopeless I dont trust that they will strap the car down correctly let alone tune an ECU. The tuners that I have talked to here don't even understand what an RB30DET is. I feel like the only thing they can tune is a dirty old V8 carby.

So I am just wondering what you guys recommend, I basiclly need an ECU that will give me decent drivability because this car is mainly a daily driver, be able to manage a fair decent ammount of power and also be fairly easilly tuned. It's a big ask but I hope I end up with something good.

Also with the E-Manage, I understand that you can plug the MAP sensor into one of the extra imputs but I have not been able to find a loom+MAP sensor to suit it. If I was going to follow down that path I would want the MAP sensor and loom with it but I can't find anyone that sells them.

Also I am not running VVT at all so that might give me some more options.

Edited March 26, 2008 by Finny

[700HP-GTR33]

You need to firstly find a tuner you are happy with and discuss your budget.

Then ask him what he prefers to use.

Saying you don't want to use an AFM is in my opinion not an option for some tuners.

Here is a link for you

http://www.motec.com.au/ems.htm

[paulr33]

you know that when you max out the AFM it runs like a map sensor anyway? ie: no more load increase, so no more 2d tuning from that point on

[**RB2530**]

I disconected my actuator so in high revs I am seeing about 3psi. I have a STOCK ECU with only a SAFC to adjust fuel mixtures so that I can sneek the car about untill I get complete A/M management. My cams seem to make all their power between 5,000 - 7,000rpm but at 5500rpm on 3psi of boost I am maxing my Air Flow Meter.....

This sounds a bit weird to me...I assume you mean you disconnected your WG actuator??? If this is correct you will not be running 3psi unless your turbo is very sick. Disconnecting WG produces higher boost not less...

...And maxing out airlfow meter at 3 psi at 5000-7000 rpm is very strange...I have rb30DET and max out afm at about 9psi...how do you make the determination that your afm is maxxing out???

[Angus Smart]

Autronic could very well be a good option.

[Finny]

You need to firstly find a tuner you are happy with and discuss your budget.

Then ask him what he prefers to use.

Saying you don't want to use an AFM is in my opinion not an option for some tuners.

Here is a link for you

http://www.motec.com.au/ems.htm

Most tuners here say PowerFC because its easy and won't really touch any thing else. Thing is these guys could probably count how many PowerFCs they have tuned on their hands. I have heard there is a decent tuner in Launceston (200km away from me in Hobart) and he is really good at tuning Microtechs as I have heard. But I can rent out a dyno and I wouldn't mind attempting to tune say a microtech or an e-manage on dyno.

I would probably go a PowerFC is they wern't so hard to get hold of and people want like $1600 for them and really there are a lot better management systems for $1600.

[chuckie]

G`day have you had a look at the EMS STINGER used in state championship`s saloon car`s + a few use them in DRAG`S ,with great feed back ,cheer`s chuckie

[Finny]

I meant removing the spring from the wastegate so its always open.

SAFC tells me AFM is at 100% when I hit about 5000rpm. I do realize that the SAFC reads 100% AFM a little bit before the AFM actually maxes but still it is at about 40% AFM at 4500rpm at 5000rpm cams start to come into efficiency and it skyrockets to 100%.

I do have a fair amount of head work, very free flowing exhaust etc. it does flow a lot of air. Engine is also over 3L.

Autronic; I have heard good things but haven't really looked into them. I think I will have to do some studying.

Edited March 26, 2008 by Finny

[paulr33]

i think you should understand how maf and map works before you make a decision

what do you think happens once the maf maxes out?

[Finny]

Well this is my interpretation, I am probably wrong tho.

Say 1000cfm of air maxes the AFM. And you are pushing 1100cfm of air. The ECU would see 1000cfm of air so there for running the car leaner and leaner as it pushed more air. I know you can just richern the mixture from when it hits the AFM max upward so that it still has correct mixtures but that is hell dodgy because you arn't going to have the exact same amount of air every time.

I am sure you will tell me that I am wrong

[paulr33]

well sort of

lets say a Z32 maxes at 1000CFM of air

and you run a big single GT 80 billion and it uses up 1400CFM of air

from 1000CFM onwards the AFM shows 5.1v so it maxes

so your load axis on your 20x20 map this may be say row 15 (near the bottom)

so from that point onwards it wont move up or down, becuase it cant show any more load

so you are left to 1 dimensional tuning - that is, the cell on the map will only move as RPM increases

so you can still tune, it wont magically lean out, you just have "less" load points to fine tune and adjust

the car wont go back, it wont melt rods etc, you just have less load points

now

lets say a 3bar map sensor that maxes at 58psi

and you run a big single GT 80 billion and it uses up 1400CFM of air and peaks at 18psi

from 18psi onwards the MAP shows 3.1v and never inceases

so your load axis on your 20x20 map this may be say row 15 (near the bottom)

so from that point onwards it wont move up or down, becuase it cant show any more load

so you are left to 1 dimensional tuning - that is, the cell on the map will only move as RPM increases

so you can still tune, it wont magically lean out, you just have "less" load points to fine tune and adjust

the car wont go back, it wont melt rods etc, you just have less load points

do you get it ?

[Finny]

Thats exactly what I thought happens.

Boost levels fluctuate and if I am maxing my AFM at 5000rpm.... I really don't want to map from 5000-7000rpm with only 1 dimensional tuning being that 5000-7000rpm is were I make all my power and were the cams are in their efficiency.

I was thinking I might just run a 50/50 AFM bypass so that I can at least get a semi decent tune just with my SAFC so I have some more time to get my management sorted.

I also assume I could just get my hands on 2x stock Rb25 AFMs or 2 Q45s and a PowerFC with read from both? I assume PowerFC is able to do that.

Also how hard is it to get an RB26 PowerFC to run in a RB25 as I don't have VVT, can have twin AFMs etc.

It's just really hard to find an RB25 PowerFC these days.

[paulr33]

yeah the 26 FC will let you run twin afms if you like

theres a few changes to make the 26 FC work on Rb25 but its pretty easy and straight forward

if boost levels fluctuate then you have a crap boost controller

it should be steady especially between 5 and 7 grand

so with a map sensor it will be 1 dimensional tuning

[Finny]

Yeah but I would most likely go something crazy as far as MAP goes, I have heard you can get 7 bar map sensors. I want to run around 30-35PSI once management is sorted.

[paulr33]

pressure != volume

they are not the same thing

you should understand that

running 5psi or 57 psi means nothing in volume

i think volume is actually less as pressure increases

[Finny]

Thats correct because the volume is more dense. Thing is AFMs run out of boost so they read the air at atmospheric pressure and not once it has been compressed.

I will have to look into getting a RB26 PFC to run on my RB30/25 as I think that will be a good option.

Edited March 26, 2008 by Finny

[Sydneykid]

Some things to keep in mind.

You can parrallel wire up AFM's, the ECU sees the average voltage and you tune from that average. This is doing externally what an RB26 Power FC does internally, take 2 x AFM signals and turn it into 1 load axis. Hence you don't need an RB26 Power FC to run 2 x AFM's.

I can plug in a Power FC and start tuning on the dyno in less than 5 minutes.

A Power FC comes with very acceptable base mapping.

An EMS/Autronic/Motec will take at least 1 full day to get to the same stage.

A Power FC comes with very acceptable cold start and run mapping.

An EMS/Autronic/Motec will take at least 3 days to get to the same stage (it has to be cold before you can tune).

So don't fall for the trap of looking at only the price of the hardware, ask how much a FULL tune will cost. By full I mean cold, warm, hot, traffic, stall, air con, power steer, limp home, fuel economy etc etc.

Cheers

Gary

[2rismo]

Some things to keep in mind.

You can parrallel wire up AFM's, the ECU sees the average voltage and you tune from that average. This is doing externally what an RB26 Power FC does internally, take 2 x AFM signals and turn it into 1 load axis. Hence you don't need an RB26 Power FC to run 2 x AFM's.

I can plug in a Power FC and start tuning on the dyno in less than 5 minutes.

A Power FC comes with very acceptable base mapping.

An EMS/Autronic/Motec will take at least 1 full day to get to the same stage.

A Power FC comes with very acceptable cold start and run mapping.

An EMS/Autronic/Motec will take at least 3 days to get to the same stage (it has to be cold before you can tune).

So don't fall for ther trap of looking at only the price of the hardware, ask how much a FULL tune will cost. By full I mean cold, warm, hot, traffic, stall, air con, power steer, limp home, fuel economy etc etc.

Cheers

Gary

Autronic now make plugins for Skylines 32-34 that come with base maps. I'm running one. Just thought I'd mention it.

[Sydneykid]

Autronic now make plugins for Skylines 32-34 that come with base maps. I'm running one. Just thought I'd mention it.

Did you have change the trigger in the CAS and/or the ignitor? They used to cause problems with Autronics. We had a Nissan at Bathurst with an Autronic no talk problem last weekend.

Cheers

Gary

[**RB2530**]

Thats exactly what I thought happens.

I was thinking I might just run a 50/50 AFM bypass so that I can at least get a semi decent tune just with my SAFC so I have some more time to get my management sorted.

I have thought of doing this before and in concept it will work and maybe some guys have used it as well...BUT

In reality I think it is very risky due to the following...

There is no way that you can be assured that you will maintain a 50/50 airflow split...I appreciate that from a tuning point of view it does not really matter if it is not exactly 50/50 airflow between afm and bypass because you just tune to to suit anyway...BUT what happens if or when the ratio between the measured flow and the non measured flow changes...This would definately happen if you were using two seperate filters...one for the afm and one for the bypass...Even is they are mounted side by side one will get dirtier quicker then the other..Also when you are tuning on a dyno you dont have road speed air entering the engine bay so your tune may instantly change as soon as you get out on the road...

If you try and use the one filter connected to both the afm and bypass to get away the above issue, unless your design is very well thought out, the afm vs bypass ratio will also change with differing atmospheric conditions such as the ambient air temp, humidity etc This is due to small changes in the flow characteristics of air due to changing temp, humidity etc etc etc..A good design would achieve laminar flow within the filter in all locations which in practise would be very difficult to do especcially when you are seperating the aiflow into two individual flows...

My suggestion would be dont do the afm bypass thing...