Evildead

running a Dawes or similar?

john banks

The map is already advanced and leaned out, so there is less safety margin than the original ECU. It already runs 1.1 to 1.2 bar depending on your exhaust and the Dawes would ruin the silky smoothness.

T-uk

john,

would it not be as good as your PPP and dawes,just a bit leaner which is what you wanted a few weeks ago .

john banks

The Tek 2 I datalogged today was running a lambda voltage of 890 mV or about 9% CO, and held boost of 17.4 PSI and fairly advanced timing. Without datalogging I would not want to increase boost further on such a car, so I would not put a Dawes onto a Tek 2. For summer use on a TD04L I would not want to be running more than 18 PSI. The PPP was running a lambda voltage of about 920-930 mV which is considerably richer - probably well over 12% CO.

Evildead

Say that i just wan't to cure boost spikes and WG creep, and set it to say 1.1 - 1.2bar ?

john banks

Then it will hold that boost as long as the wastegate can manage - probably to over 5000 RPM, and it may also make rather a lot more boost on part throttle than the Tek 2 is mapped for. All this should be compensated by the MAF sensor, but this is untested water and I would not put it on my car without data proving it is safe. The Dawes may give you a lower boost threshold, but in so doing you may actually lose torque because the wastegate will be closed and all the exhaust gas will be trying to spool up the turbo, this can feel a little choked, and using a normal duty cycle method is arguably superior. I would leave the Tek 2 as it is, if you want more get a new turbo and a Tek 3?

Evildead

John...why so paranoid?

Thing is that the OE solenoid is a pretty wacky solution, i'm getting tired of cleaning the ******* once a week (my oil level is correct), sometimes i get boost spikes up to 1.4bar, then a
ECU retard, down to 0.8, then another peak and so on.

As i understand it, if the Dawes is mounted between the solenoid and WG (set at same boost)one still have some kind of safety, and high rev boosts will be the same as before since the OE solenoid will open up even more...well, maybe, i haven't tested this.

Evildead

Thanks John, valuable input!

I'm running 4" cobraneck DP, 3" decat and K/N induction, so the TeK2 is pretty much on spot for me. I'm also flowing my headers next weekend, well i guess i'll continue cleaning until i get the software also.

-Chris

john banks

The headers will make your boost control even worse I reckon But I did mine at the same time as the turbo swap so I don't know the independent effect personally.

Evildead

What turbo are you running? I guess swapping unit is not a bad idea at all.

21 PSI are in the regions i was with my old XT 10 years ago
(enough to smoke a stick operated Dodge Challenger with 450+)
i still have sweet tastes coming up sometimes :O

-Chris

john banks

I can't give any details about the turbo at present until it is fully tested, but when I can you'll be the first to know

john banks

If you run the oil level at less than a third of the way above the bottom notch/hole/whatever on your dipstick, then your Tek 2 should fix it since it is mapped around a decat exhaust, so clearly there is a problem if you are spiking to 1.4 bar. Otherwise there is a fault - the OEM system is the standard for many turbo cars - more problems occur with exhausts and overfilled oil as it is operating outside normal parameters. Inside the correct range it gives closed loop feedback control, atmospheric pressure compensation, limp home and knock control and is actually quite sophisticated.

"if the Dawes is mounted between the solenoid and WG (set at same boost)one still have some kind of safety, and high rev boosts will be the same as before since the OE solenoid will open up even more...well, maybe, i haven't tested this."

No they won't - the OE solenoid is not connected pneumatically at all if you are using a Dawes to control boost. The solenoid has no control whatsoever, otherwise you have two conflicting closed loop systems working on the same process and your boost control will be unimaginably bad.

Dawes has been tested fully by myself and others on standard and PPP ECUs - all these have considerable margins. The Tek 2 is pushing things more than the PPP, but still safe as it is, data is not known if you go further. If you have the facility to test it all yourself then that is a lot safer - I would want Delta Dash logging at least, and preferably some means of recording EGTs as well. Otherwise you are tuning in the dark - there is a fine line between a nicely running car and a dead engine. It is not paranoia it is responsible data collection and safe decision making with a margin for error.

I'm not at all averse to running 21 PSI and ridiculously higher airflow than the original ECU is mapped for as I do at present, but only because I have data.

[Edited by john banks - 5/9/2002 10:42:53 PM]