My Delcoed Rides

[delcowizzid]

its actually good that you havnt fitted a cooler yet means theres plenty more in it yet . i nearly bought a bedford this week LOL

[Holden202T]

yeah im hoping the cooler will help things, i have never been able to screw anymore timing into it either, been too busy making everything work, its just a timing map from 13.5:1 comp N/A 202 thrown into this one (with 9.3:1 comp) and timing taken off 100kpa as it goes into boost, i can't hear it ping but i haven't been able to get it on the dyno and all work to be able to tune more timing into it either!

who knows maybe i've nailed the timing and it wont take anymore, but i reckon theres some in there to be had!

you would want to have a good reason not to buy a bedford

[VL400]

Congrats on the 10, been a long time coming and was great to see it finally run one - and not just breaking in to the 10s, smashed it!

Good think the module was sorted out. So what was R5 used for?

yehaaa.im sure i heard that pop in some earlier vids i remember mentioning it.

Yeah there were pops in other videos but was from a different issue. Lots has been learnt since the hardware/firmware holden202t was running prior to this meeting.

The changes made to the hardware were for noise filtering on the reluctor inputs along with ECU inputs/outputs. I dont have a car running a 36-1 trigger so all trigger testing was done either on a simulator wheel or on my car running a 12 tooth crank trigger and cam trigger. Both ran flawlessly, but throw an engine in to the mix using a different model of reluctor sensor/trigger and it all went to crap! Prior to the hardware mods the thought was either noise spikes causing problems or the trigger signal level was too high. The R5 mod was to reduce signal level but it caused a small phase shift, with the missing tooth trigger it meant the missing event was not detected at high RPM causing a sync loss fault due to falling outside the allowable tolerance window. On other trigger types it did as expected and reduced levels without a problem. Removed that resistor and left only the new noise filter circuit in. Seems to be much better now!

Firmware changes are where things really improved. The '808 handles fuel and spark very differently to other models, and it does some very weird things. The ECU uses a reference pulse from the dizzy/crank sensor that it knows occurs at a defined angle and then calculates (based on time) when to fire the injectors and coil. You would expect the ECU to stop outputting fuel and spark immediately when it loses the reference signal as it will not know what the engine is doing, you cant guess the reference pulse. The '424 VR PCM does stop, the '808 style ECUs do not. It instead does some crazy dwell times firing at the wrong time.

So now if a trigger/sync error occurs on the ignition module it pauses spark, stops sending ref pulses to the ECU, gains sync from the crank/dizzy trigger again, drops to handling spark itself and then continues sending ref pulses to the ECU without a single spark at the wrong crank degrees. It then waits for a configurable number of valid ECU EST pulses before letting the ECU control spark angle and dwell again.

The backfires still occur once the module starts handling spark again as the ECU was outputting injector pulses when it was not seeing ref pulses during the crank/dizzy resync. Key bangers FTW

[vlad01]

great explanation. So is there a reason the 808 continues to output in the event the ref is lost? Is it a design limitation of some sort?

[VL400]

The main processor in the 808 sets up a second IC that handles fuel and spark when the ECU is operating normally or when in proper limp mode runs from the netres, its this second IC that appears to cause the problem and not running code from the bin we are not able to change how it operates. It is also the reason we cant add a spark cut rev limit option on the '808

[Holden202T]

............

[v6bucket]

Well done on the 10.54.

[Holden202T]

thanks!

[immortality]

Congrats mate. Same to VL400 who's tech lets us achieve results that defy belief.

[Holden202T]

Couldn't agree more!! I'm not sure his modules in the car necessarily make it go any faster but they sure do make it more high tech and I personally reckon they'd have to have taken .46 sec off the times for sure!!