Tuned stock Ecu, old t3/t4 turbo, sard FPR, Walbro fuel pump... 17psi.

 

That graph doesn't make any sense.
How does it start out at over 300 lb-ft of torque?

How does the stock ECU work at 17psi???


-Ted

 

Yeah, really... you'd have to flip that TQ curve backwards to even start making sense.

 

I dynoed on a dynapack.

they hold you at something like 3000rpm and make you mash the gas in 4th gear at about 12psi, they release soemthing and the run comes out as you see it.

Granted I wouldn't make that much torque on the road because I could never make 17psi that quickly unless I was on a really steep uphill grade, but the chart is and indication of what the motor is capable of.

But on the road, the car pulls really well from 3500 - 5500 and then tapers off.

The ECU has was purchased from my friend Atsushi in Japan. It's got a few cool features. I've been able to disconnect the OMP, and TPS with no driveability issues (well, without the tps the injection doesn't shuts off on decel, so i get backfires). Mind you I don't leave these thing disconnected, I was just checking. I don't know if this is a stock feature or not, but the rpms are increased 200rpm when you put the car in gear to prevent bogging. I didn't notice it before putting the new ECU in.

I'm really a neophyte when it comes to ECU's and such so I'm just naming some of the things I noticed since putting the ECU in. If you have questions that you like to have answered to maybe give you an Idea of why the dyno came out like that, feel free to ask. I'm curious too.

 

Oh... the turbo has a .49 hotside and a 1.08 compressor. It's got to be at least 20 years old, but it works.

 

You don't understand.
The stock boost sensor is a "2bar" pressure sensor that can only read up to 15psi of boost.
Any boost over that, and the sensor and ECU have no idea you're boosting that high.
...unless you're running replacement boost sensor that can read that high, but I highly doubt that.

Therefore, there is no way the boost sensor or ECU can compensate for running over 15psi.


-Ted

 

So the ecu will just keep injecting fuel for the 15psi reading?

Do you think it's possible to crudely compensate for that limit by increasing the fuel pressure? I'm just asking for the possibility, not actually stating that this is how it works.

I've actually hit 20psi once or twice, but it wasn't for very long.

 

Yes, any boost over 15psi, and the ECU stops doing anything.
Due to the stock boost sensor, ignition timing retard stops.
You're probably running over 15-degrees of total advance (most likely 18 at least), which is way too high for that much boost.
The stock airflow meter is close to maxing out; the airflow meter is the primary load sensor for the stock ECU.
If it is maxed out, the stock ECU will stop adding fuel.


Yes, it's possible to run an aftermarket boost-dependent FPR that runs higher ratios of fuel pressure versus boost.
This is one of the old-school tricks of getting more fuel into the engine without messing with the electronics.


-Ted

 

I'm guessing that the Sard regulator unit is probably doing that then. Fuel pressure is between 60-70 psi at full boost.

 

What is the fuel pressure at idle?
What is the fuel pressure when you first let the fuel pump prime prior to cranking the engine over?


-Ted

 

.49 hotside...

i'm assuming its not working too well due to the amount of power its making.

 

Fuel pressure at idle is ~32psi. I can't honestly say what the fuel pressure is just before cranking the engine over. I only had the fuel pressure gauge hooked up when I installed the pressure regulator and the pump, then I gave it back when I was sure it increased the pressure.

 

Well, it feels pretty good. I've pulled on a couple cars, but I can't really speak about their state of tune.

The problem is, I don't know of any FC's in the area that are well tuned so I don't know what they are supposed to feel like when they're setup right. All I can say is this is a dramatic improvement over stock.