Bigfoot928

that is insane power.... I'd imagine you could get more if you went to a stand alone ecu like some of the newer motec's.

Fabio421

Actually, yes, you are correct. My mistake. I was thinking about the wrong runs. It was just a hair under 700 at the end of the previous day and just over 700 the next morning. Sorry about that.

ptuomov

I share your sentiment. So far, only andy-gts has been posting official acceleration runs for the recent builds. His standing mile 171.2 mph trap speed is impressive. By my back of the envelope math it translates to about 128.4 mph 1/4 mile trap speed and about 6 lbs / average hp.

My car is not strip or track ready yet, for three reasons. First, there are some traction control issues on first and second gears with my current tires. I need the boost profile selection to run automatically off the shifter and fit wider and stickier tires. Second, especially with wider and stickier tires, the g-forces are such that the stock oil control may prove an issue for the stock engine. Something needs to be done there. Third, for longer test stints, I need to have the transmission oil cooled. The engine cooling will also possibly become an issue for longer runs.

There are three check valves. One near the front of the car and one each at the pump outlets.

We're really just scratching the surface of the potential for this engine here. It looks like the stock engine and stock ecus can possibly take the car to as high as 800 rwhp. Whether it is possible remains to be seen.

Right now, I don't think we'd make much more power with a more recent ECUs. Where do you think a modern ECU could make more power with the current engine?

Lizard928

more efficient ignition system capable of a much stronger spark can help.

Why 3 check valves? I only see the need for 2.

With stickier tires, you do run the risk of breaking things....

Tony

WOW...thanks for that.

ptuomov

I've been thinking about Sterling's comment and my response. I still think that LH/EZK with JDS software aren't leaving that much power on the table, except at high rpms where the JDS maps don't have resolution.

In terms of the ignition system, since we're running 93 octane pump gas (not racing gas or ethanol) in a 9.4:1 compression turbo motor, we aren't experiencing noticeable misfires nor are we expecting any. Where's the benefit from a higher voltage ignition system?

In terms of the fueling, I am guessing that we have very good fuel atomization. The charge is hot, dense, and turbulent. Sequential injection is not going to give us significant cooling or atomization benefits. Also timing the pulse from injectors to fill the cylinde better is an insignificant drop in the bucket when you have a turbocharger force feeding the cylinder.

If there's something to be changed about the stock computers, it's that we would could use:
(1) more resolution at higher rpms
(2) the ignition and fuel grids to coincide
(3) individual cylinder fuel and ignition trim maps
(4) boost control integrated with ignition control and knock sensors
(5) traction control integrated to the ignition control and boost control

Those would help by making tuning easier and car faster on track. I don't think they'd help that much with the peak power dyno number. I might be wrong, though.

The third check valve is a legacy from when the car was running a single Fuelab pump.

I agree that changes may have to be made to counterbalance the increased risks from stickier tires.

BC

The tuning benefits that come from after market ecu units cannot be brushed aside. Knock control at the limit, fueling precision, etc create large differences.

worf928

But, will it give you better control of the air-fuel ratio?
... through the stock intake manifold in your case.

Somewhere, deep in the bowels of Forum History is a thread in which there appears a picture of a 928 with 8 wide-band oxygen sensors and some accompanying discussion of the A/F variance across the cylinders. (That's all I remember: 8 O2 sensors, A/F variance. I don't remember who posted it, who's 928 it was (Simard?) and if it was NA or FI (and what flavor FI if FI.))

worf928

Oh, BTW: 700+ rwhp!

BC

Todd

blau928

Tuomo...

1-5 are possible with a Motec or other ECU..... The peak may not change, but the curve may get more area.. Just my $0.02

ptuomov

I agree that we might get more power using the individual cylinder trim tables, which was #3 of my list of potential benefits from an aftermarket ECU.

Contrary to other people's experiences, we don't get some cylinders knocking much earlier than others as we lean the fuel and advance the spark, so this is not the most pressing problem right now. We're in a minority with that opinion and experience. We're also in a minority thinking that the stock intake manifold is not the most pressing bottleneck in the turbo engine as currently in the car. All the current bottlenecks for more power are control problems, and after those control problems are solved two larger turbochargers are needed before we see any need to change the intake manifold. Eventually, it will have to go, too -- just not yet.

It was Todd Tremel who run the 8-sensor WBO2 test with an Autronic ECU and Hacker who posted about it. That was very useful information for them to share with the community. It's not a coincidence that Todd Tremel holds the current 93 octane pump gas, stock long block peak power record at 722 rwhp.

We don't have a practical way to run an 8-sensor WBO2 system on this car. It is very hot and very crowded in there around those exhaust manifolds, and the exhaust test ports in the head are very hot and very inaccessible. A more practical alternative for this engine would be to run the TFX cylinder pressure sensor system with pressure sensors in the spark plugs, which would allow for a lot more data collection than inferring the optimum fueling. The downside of this system at this point is that the cheapest model starts at $7k, install and debugging is time consuming, and our the stock ECUs don't have an individual cylinder trim so I am not sure we could do much with the info right away.

It's a good result, but nobody's popping champagne bottles here yet...

The peak would probably improve a bit, too.

Here's my view: If one wants to blow many thousands of dollars on this engine, I believe that right now at this level there are much more cost effective ways to do that than to go to an aftermarket ECU, all new wiring, etc.

blau928

I agree that it is expensive for some additional functions like traction and individual cylinder trims..

This is great info, and I can only say great going on the incremental tuning.

Have you measured the pressure drop across the system before and after the IC and in the manifold..?

I will gladly send bubbly when you get to 800

Lizard928

The cost of some standalone systems is very high, I do concur.

But some systems really are not that expensive.

VEMS for instance has tons of features, lends to MUCH better fueling control over stock system, switching to COP lower RFI, as well as the ability to run much larger gaps (think .045" up to 30 PSI ).
One of the key benefits as well imo is switching to MAP and being able to ditch the MAF. This gets you much more consistent fueling, no worry about turbulence in the air stream, among other benefits.
This system has dual knock control, built in EGT (with targeting), can have knock control, boost control, meth injection control, built in WB controller, and 3d map tabling with the ability to change the RPM columns to be able to get more resolution where you need it.

the cost for the brain, connectors (WB, knock, hall, injectors) is 730 euro or $955 usd. You will need to get an ign system setup on top of that, so say around $300. But all told, this is pretty cheap if you complete the install yourself. If you pay someone to install and setup for you, then it gets more expensive pretty quickly. But this system is more than capable.

U-928

Don't quote me, but IIRC, you the newest mega squirt MS3x should be able to handle all of those goals, without the need for an external ignition system. Also has fuel and ignition switching capability which could then produce essentially double the fuel and ignition map resolution.