Wolf 3D V4 vs PowerFC

[N I B]

Do what you want its your car.

[Cubes]

Steve,

So does the wolf3d v4 have sequential injection for the RB?

Do what you want its your car.

Was that directed towards me?!?!

[JimX]

Originally posted by -Joel-

Was that directed towards me?!?!

I thought it was directed at me, but it didn't answer the question

[Sydneykid]

Hi Jimx, the Apexi drag R33 GTR (V-Max) makes "over 1,000 hp" using a PFC and AFM's. It ran an 8.75, so I suspect it's was closer to 1,100 hp but that's what Apexi quoted. On a 1,000 hp RB I would personally use a Motec M8 (min). Compared to the cost of building and maintaining that sort of engine, the extra cost of a Motec is relative peanuts.

Plus I would almost certainly run a Motec dash and interface the ECU so I could data log every race/run That way I have all the necessary data to make the car faster.

We run Datalogit on the Power FC's in the race GTR for exactly the same reason.

Steve-SST is absolutely correct, each ECU has its strengths and weaknesses.

[SHUTO-BOY]

dont forget to bring me for a ride in the supra one day Steve, just dont get jailed heheh

im attempting 400rwhp with my lil hi-flow, to show some more results from using wolf3d,we'll see how it goes after the rebuild

[the phantom]

Hey Steve-SST,

Does the Wolf 3d you have mentioned have fully sequential injection for the R33???? Or does it have only the 4 injector drivers requiring a semi batch arrangement.

I cant help thinking this is pivotally important in explaining the great power outputs you've achieved with this ECU. According to my knowledge, fuel pressure increases do not equate linearly to injector flow. I know Sydneykid made some calcs previously and relieved his puzzlement, but he also suggested linear flow increases with pressure. Unless someone can confirm this relation, this leaves the sequential/batch argument for the explanation. Does this explain the huge power levels with plenty of reserve duty cycle that keeps being mentioned???? With any batch firing the injector would fire twice for each cylinder rather than once per 2 revolutions as per full sequential, thus explaining the ability of 370 cc injectors with only marginal pressure increases being able to support such outputs. Firing twice would make a 370 cc injector appear like a 740cc, except that half the fuel waits around for a bit before being ingested. In the FC with its sequential firing, does this explain its quick duty cycle limitation. In this system the injector has only a certain number of cam shaft degrees when the inlet valve is open to squirt in the fuel. As it ALL has to be injected at once, and since the inlet valve is only open for so long, the "duty cycle" limit simply means that the valve has closed and so fuel injection can no longer occur. If it were to keep going passed the closing, then the sequential idea would be lost and it would essentially become a batch system.

I have no intention of making a wolf/FC comparison here...I just want to know whats going on.....

[Gradenko]

the phantom, I had the exact same thought. But I researched batch firing a little more and found it doesn't make a difference to duty cycle like I thought it would.

With batch fire, the ecu fires off two injectors at once. That doesn't mean each injector is fired once a revolution. The two injectors triggered are chosen such that their respective cylinders are fired in succesive order. The two injectors are timed to trigger at the beginning of the first cylinders firing event. This means one cylinder gets fuel at the right time while the second cylinder has fuel sitting in the inlet tract for a short time before the valves open.

So each injector is fired once per two revolutions as normal, just that half the cylinders will have less than perfect atomisation and ultimately, more emissions and less effeciency.

[Cake]

just had a look on the wolf site

noticed theres a v4 and now v4 Plus. Differences between the 2 are here: http://www.wolfems.com.au/products/enginem...ersion4and4plus

are you stocking the v4 Plus yet Steve SST? Are they much more pricey in comparison to v4?

[Gradenko]

b005t, the v4+ has been around for a while and is what the RB25 plugin wolf is based on. Which why the wolf plugin has 6 ignition outputs and the rest of the fruit.

[Steve]

Power FC knock detection update.

I just had a look at my pistons (head is off), and the things look almost new (except they are black of course).

60,000kms on the clock and they are pristine (also the bores are perfect with no lip, and the chambers look spot on too) absolutely not one sign of any detonation at all.

In the past I have had knock readings as high as 98, but always backed off as soon as the check engine light has flashed.

I know this isnt a quantifyable example, but at least I know its doing its job, so I am happy.

And for all you wolf, microtech etc guys that dont have in built knock detection, I would go out and spend the 200 odd dollars to buy one:D cant hurt.

[N I B]

Any WA Wolf questions email me. [email protected]

In the other states email your Wolf dealer.This forum is not ment to be a traders forum and some people rightly don't like it to be so i'm only posting as a Nissan fan from now on.

[Sydneykid]

Hi Guys, been in Perth checking out the import seen (not really, work actually). But I didn't notice any more Skylines than we have in Sydney.

Couple of people asked some questions...........

Duty cycle of 80% means the injector is open 80% of the time. Not just when the inlet valves are open. So 100% means they never close.

A true rising rate regulator increases the fuel pressure at a rate greater than the boost increase. So 50 psi fuel pressure at idle (zero boost) may be 60 psi at 6 psi boost, 70 psi at 9 psi boost, 80 psi at 13 psi boost and 90 psi at 17 psi. If the pump will support that level of fuel pressure of course.

A rising pressure regulator (as distinct from rising rate) will follow the boost. So 50 psi fuel pressure at idle (zero boost) will be 56 psi at 6 psi boost, 59 psi at 9 psi boost, 62 psi at 12 psi boost and 65 psi at 15 psi.

Using a rising rate regulator can easily give the sort of fuel flow required to make 400 + rwhp out of standard injectors, but it stresses the injectors way past their design limits.

Obviously squirting fuel into the inlet port when the inlet valves are closed means that the fuel has to wait until the valves open before it can enter the combustion chamber. While it is waiting, the fuel de-atomises and therefore when it finally flows into the combustion chamber, it doesn't mix with the air as well. This adversely affects both power and economy.

This is one of the reason why the Group A Skylines ran an engine driven fuel pump, it gave very high pressures and excellent atomisation of the fuel which facilitated more power. I have seen as much as 140 psi at the fuel rail. Injectors have come a long way in the last 10 years and don't require the same pressures to achieve good atomisation.

Hope that answers the questions

[the phantom]

Thanks Gradenko and Sydneykid,

So past a certain duty cycle, the whole argument of sequential vs batch becomes irrelevant, as the distinction between the two then dissapears???

Sydneykid, can you confirm that with standard rb25det 370cc injectors that going from 38 to say 76 PSI fuel pressure doubles the flow to 740cc, ignoring the reliability issues you have warned about??

[Sydneykid]

Mr Walker asked "past a certain duty cycle, the whole argument of sequential vs batch becomes irrelevant, as the distinction between the two then disappears???"

You are correct at 100% duty cycle it makes no difference. The more you move away from 100% the more relevant it becomes. The real issue here is you can get more power and better fuel economy from a 700 cc injector at 50%, than you can from a 350cc injector at 100%. As long as your ECU can accurately control the 700cc injector of course, not all can. I have used 1300cc injectors with Power FC’s and they control them perfectly.

The Ghost Who Walks also asked "standard rb25det 370cc injectors that going from 38 to say 76 PSI fuel pressure doubles the flow to 740cc"

I can absolutely say this is not the case, although fluid dynamics is not my specialty. I would have to dig up my notes, but from memory, it is close to an inverse logarithmic increase. This is why true rising rate regulators are calibrated this way.

Hope that answers the questions

[GTS-t VSPEC]

Sydnyekid, Can I ask if you did anything special with the PowerFC to control the 1300cc injectors, as mates of mine found that the computer fair shat itself trying to control 1000cc?

[N I B]

Ants GTR has 1600cc injectors and this thing will be one of Australias fastest true street Skylines. Fabs GTR found the limits of the PFC and its now been sold (the ECU).The worst thing about PFCs and big low impedance injectors is the need for a risistor loosing the fine control needed for large injectors.Keep an eye out for our cars showing the results as i think real results are the only indication needed not fancy words.We often have feature cars in Oz mags, the next is Dragster Australia.