R33 Rb30 Conversion

[Sydneykid]

Hi GiJOr33, the 15 or so features I posted for the Motec are in addition to the 17 or so mentioned in the Zoom table. There are other additional features on the Motecs, but I believe, for the sort of application JNR24 has, these were the most applicable.

Hope that clarifies

PS, I understand the new Microtec is designated LTX16, although there will probably be an MTX16 for generic applications. The closed loop operation will go a long way to fixing the fuel consumption problems as well.

[GiJOr33]

yeah... i was just posting the link again. That zoom article is based on the middle range modified cars... Gives a bit of a review on what's about...

although not everyone will know what all the features are and do!!! (i'm one of them) The LTX16 does look good though... If i had the $$$ i'd go a Motec!

[JNR24]

Could someone elaberate on the ECU guide a little bit? Does the INJ Drivers mean that: eg the MoTeC M4 is only suitable for 4 cylinders? and the M48 is good for 8s, 6s, & 4s?? or 6 with 2 additional injectors?

And IGN Outputs what are these used for? something to do with coils/ coil system?

And has anybody noticed that the Apexi FC has a "OPTION" under the primary sensor option? (i thought the Apexi FCs only used AFM?)

And what all that other stuff means: eg ACCEL PUMP? STEPPER MOTOR? CLOSED LOOP? TEMP COMP LAMBDA?

Sorry if you have posted this previously GiJOr33, but all info in this thread is relevant to the RB30 Converstion & anyone looking for info on the conversion will be able to find it in here.

Thanx again guys,

Trev

[Belly_up]

JNR24,

hopefully i can explain a few of the things you've mentioned:

ACCEL PUMP means acceleration enrichment, and gets it's name from carbies, which have a small pump connected to the throttle. It allows you to tune how much extra fuel to add when you step on it.

STEPPER MOTOR is another way of controling the idle air valve (using a stepper motor obviously), as opposed to a solenoid. Many modern engines use a stepper motor, but not all aftermarket ECU's can run them.

CLOSED LOOP means that the ECU can do closed loop fuel control at low loads (ie cruise and idle), it uses the oxy sensor in the exhaust to constantly adjust the mixtures to try and maintain an stoich air/fuel ratio. Ecu's without this, such as the Microtech mentioned above, will perform fine under high load, but will have poor economy when cruising or idling, which is especially bad if you do lots of long distance trips.

TEMP COMP, means temperature compensation, whereby the ECU can vary the fuel mixtures based on a given temperature, most commonly intake air temp, but some, like the Motec that SydneyKid mentioned, can also do engine temp compensation, and exhaust gas temp compensation. Standard ecu's don't need intake air compensation if they run off the AFM, as it automatically adjusts for air temp, but MAP based ECU's need a seperate sensor and compensation map to do this.

LAMBDA i'm not too sure, but it would be related in some way to closed loop? it may be related to the ability to utilise a wide band O2 sensor.

Hope that helps

Belly_Up

[JNR24]

Thanks for that Belly_up!

What about my statment regarding injectors & igniton?

also..... no idear about the Apexi FC thing?

[Belly_up]

The injector drivers idicates how many injectors you can run in sequential fire mode. you can actually daisy chain injectors together, so what it actually means is that you can run up to 4 *banks* of injectors, but all injectors on a single bank will fire at the same time. So if you have 6 injector drivers, you can run all 6 injectors in sequential mode. or 12 injectors, in banks of 2, etc.

Ign outputs are much the same, if you have the same number of ign outputs as you have cylinders, then you can run an individual coil for each cylinder, the same as the factory nissan ecu does. if you have less though, you have to run a "wasted-spark" setup, where you run 3 coils, and each coil fires 2 cylinders at the same time. the two cylinders are chosen so that one is at the top of the compression stroke, and the other somewhere (not exactly sure) that the spark will have no effect. The effect of this is that you double the duty cycle of the coil, and it will produce a slightly weaker spark, although still better than a traditional single coil setup.

So basically the bare minimum you need to run an RB on an aftermarket ecu, is 3 ign drivers, and 1 injector driver (to run all 6 injectors in batch fire mode). The single injector driver would probably result in poor low RPM economy and performance. If you have 6 injector drivers and 6 ign drivers, then you can replicate the perfomance of the factory ECU - with appropriate tuning of course.

It's not until you look at aftermarket ECU's for a while, and look at some of the features they are starting to introduce only now, that you realise how clever the factory ECU really is, and the R32 ecu design is now 14 years old. Those factory engineers are clever buggers...

Belly_up

[Sydneykid]

Hi JNR24, see if I can answer...

Accel Pump, when you put your foot on the accelerator the ECU adds a bit of extra fuel for a very short time to make the engine accelerate instantly. If you had no accel pump, the engine would slowly gather rpm. The ability to adjust how much fuel and for how long is very important in tuning a car so that it has throttle response.

A lot of people complain about poor throttle response in turbo cars, you can help this a bit by tuning the accel pump. It won't fix a problem of too big a turbo, but it can help.

Stepper motor, some cars use a little electric motor on the throttle butterfly to adjust the idle. It moves in small increments and then stops, hence "stepper". Other cars use a solenoid controlled air bypass system, instead of opening the butterfly to let more air in, it goes around the butterfly in a separate passage. Obviously if you car uses a stepper motor to control the idle and the ECU does not support that function, then you can't get your car to idle properly.

Closed Loop, the lambda sensor tells the ECU that the car is too rich/lean, the ECU leans/richens the mixture, the lambda sensor tells the ECU the mixture is right. Hence closed loop. This is used for lowering emissions and for cruising fuel economy. The lambda sensor used in most cars are what I call slow and narrow (and cheap). They only measure the A/F ratio in a small band and they do it very slowly. That is OK for idling and cruising along at small throttle openings. When the RPM increases or the throttle position is moved rapidly there is not enough range or time for the lambda sensor to work out the A/F ratio.

There are fast and wide lambda sensors, they are the ones we use on the dyno. They are expensive, about 30 times more expensive than the standard car ones. That's why cheap A/F ratio displays that use the N&S lambda sensor are next to useless.

One of the things we use the Motec F&W lambda sensor for is on-t rack tuning. It is very hard (expensive) to duplicate the exact conditions you get at a track in the dyno room. So we tune the car pretty close on the dyno and then take it t o the track, drive it around for a couple of laps and the Motec fine tunes itself.

Temp Comp, temperature compensation can be engine water temperature (EWT), engine oil temperature (EOT), inlet air temperature (IAT) or exhaust gas temperature (EGT).

The EWT tells the ECU when the engine is cold and needs to be run a bit rich until it warms up. It can also tell the ECU when the engine is too hot, so the ECU can add a bit more fuel, turn down the boots, lower the RPM limit, switch off a cylinder or 2, all to help cool the engine down.

EOT is good for the ECU to know as it can also take corrective action if it gets too high. Plus, as anyone who has run out of water will know, the EWT doesn't work 'cause there is no water around it and you don't know that your engine is overheating. EOT is a good back up.

IAT, very import as the engine can detonate on hotter days that when it was tuned. If the ECU has this feature, you can build a compensation table and retarding the ignition timing and richening up the mixture.

EGT, very useful on a turbo car as the ECU can identify too high a temperature in the exhaust gases, that can damage the turbo. It can then take action, richen up the mixture, lower the rev limit, retard the timing etc.

All of these extra features cost money to provide in the ECU, mostly in programming time and little bit in hardware, such as increased size of memory and faster speed of processor. Plus of course you have to buy the sensors them selves.

Hope that helps

[JNR24]

Thanks heapes guys for covering this !

Looks like the computer is going to cost more than the motor! =)

[Sydneykid]

Hi JNR24, "Looks like the computer is going to cost more than the motor!"

If that's the case, you are probably looking at the wrong ECU for your purposes.

My "rule of thumb" is that you should allocate 1/3rd of the engine improvement budget to the ECU (and it's support systems) and tuning. So if you are spending $10K on an engine, then $3k is about right on the ECU (and it's support systems) and tuning.

Remember it's a "rule of thumb", not a precise requirement. A guide to say that if you are spending $20K, then $1K or $2K on the ECU (and it's support systems) and tuning is not doing the job appropriately.

How many $10K engines do you need to save to justify an extra $1K on the ECU (and it's support systems) and tuning?

Hope that helps

[JNR24]

Thanks Sydneykid,

I was speaking to Matt.lowth, (440RWKW R33) Rb30/25. And he is running a Z32 AFM with a APexi FC!!!???!!?

Generating a proven 440RWKWS>>????

WTF!?

is this possable? or is his computer possesed!?

[Cubes]

Matt lowth is making 320rwkw is he not...

[JNR24]

Sorry Joel you were correct, i asked him just now in a email and it is 440 @ the flywheel. =)

Woops!

[Cubes]

Still 320rwkw is apparently out of scope for a Z32 AFM.

[JNR24]

i think they are guides more than anything... Because Matt shouldnt be able to produce the amount of power that he is !

Looks like i should run a Q45 AFM with a ApexiFc, my power aim is the same as matts. i would be perfectly happy with that! 320RWKW.

Now next step:

getting the AFM?? does anyone know were? and how much?

[JNR24]

Quoted from matts email:

My car is making around 330rwkw and the AFM is up to

about 4.8volts (so 0.3volts of resolution left)...

turbo - it's a hybrid T04R/T66...

[Steve]

110kw loss for driveline? Seems a bit high. Is this estimate or engine dyno and roller dyno?

[Cubes]

Thats about right Steve..

The more power you make the more friction you create the more heat etc.. which is lost power.

i.e 160kw at the flywheel X 30% = 48kw loss. There for approx 112rwkw at the wheels.

or...

400kw at the flywheel x 30% = 120kw loss. Therefor approx 280kw at the rears.

Its only a rough guide but u get the gist.

Its actually similiar to future values and present values that we have covered in accounting. Could apply the formula's and theoretically it should work i.e going from rwkw(fv) to flywheel kw(pv) etc etc.. dribble....

[Steve]

I see where you are coming from Joel, have heard that theory before, but also the 'fixed loss' theory - ie with same running gear, the loss will be xx amount with only a small variation to allow for additional heat loss.

So which one is correct?

Doesnt make sense that if you turn the boost up for every 100kw at the engine, the gearbox,diff and wheels will chew up 30kw. (or does it) Becuase if you had a 600kw engine, that would mean at the back end you are only putting down 420kw, or 180kw driveline loss - that must be enough heat to cook a chicken in about .0000012 seconds ....j/k about the chicken

I would be really interested to see before and after, or BHP vs RWHP dynos on cars...it all gets a bit confusing sometimes.

[TasGTR]

If you use N/A piston's you could bring the comp ratio up by having the block machined down say (080) and the out side edge of the pistons machined down (080). Then you have to modify the cam belt tensioner by adding double (160) what you took off the block and pistons. This is how I brought the comp upto approx 11.5 -12:1 on my N/A RB30.

NB: those figures were only examples.

The cam belt you want to use is a Dayco 94407. It needs to have 152 teeth (11 teeth long than a RB25).

[Cubes]

Yep thats it TasGTR.. You got the part no. right

I'm not quite sure where you are coming from with regards to compression as after all the machining wouldn't you be simply better off getting a custom set....

We are building for a turbo motor so with the RB30 NA Pistons the CR with the RB25DE head is around 8.3:1. With the RB30 T pistons you have a cr of around 7.1:1.

It is a pretty simple conversion really Bolt the RB25DE (non vct)head on with a RB30E head gasket grab a dayco 94407 152teeth belt grab a new tensioner and idler slap the cam belt on line up the position for the new tensioner drill tap and off you go

Or you could use a 150 tooth belt and use two tensioners one replacing the idler and that will pull the belt tight enough but i don't like the idea personally.