Kevin - I will be adjusting the trigger as soon as I can get a handle on where it should spray and where it needs to spray for it to work.

It sounds like this is a problem with the DDS3 junction box? I'd prefer not to have a handicap of lowering it below wastegate pressure - I would hit that quite often even in daily driving!

 

which version of the junction box do you have? if you open the box up, it will have a label that says DDS V8 or V8a or V9

 

Kevin,

Your summing up was very accurate.

The first version of the v8 (~2s grace) never have those problem. Then came the conerns expressed by users. So, we reduced the grace period to 0.06mS. (Oct 07 to April 08). On the V8a and v9, we have increased the "grace period" to ~125-200mS. Just have to wait and see.

I was try to explain to people that the 2s grace period during throttle ramp up is not too long due to acceleration and decelleration enrichment by the ECU. AFR is always richer during those periods.

You are absolutely correct about the setting the trigger point between wastegate pressure and meths flow quanity. The SC also have the effect on how fast the flow sensor signal ramps up.

 

I feel bad about the problems that exist with the v8a boards as I was one of the users initially concerned about the 2s grace period. Live and learn I guess.

 

Dudical26, please do feel bad. You have done us a great deed by pushing the boundary. I must admit, dropping down from 2000mS to 63mS response time for the sensor was a geart challenge for us. We have worked on the sensor non stop since last year this time.

Your logged chart has given me some clue how the sensor responded in real life situations. You can see the response time constant of the flow sensor is around 70ms. Based on the full scale of 100ms.

A few days ago you have asked what the grace period is now, I replied ~120mS. Today we have the chart to confirm it is well within the capability of our flow sensor.

 

yeah dudical! please DO feel bad! you have caused me nights of no sleep pondering how to make the WL work with triggering points over wastegate pressure

 

If what KevinD says does not fix it, I would say it may have to do with the wiring/pluming of the mac valve. I know on Bushar's Evo his MAC valve was plumed incorrectly causing it to run on wastegate pressure instead of the MBC. However this sounds more electronic than pluming. Good Luck!

 

Richard - I will be unable to actually drive the car until later this week to check out what the kit does with the WL 7-8 clicks from minimum...however, I just looked at the junction box and it's the DDS3 V8a, and the trip adj is pointing straight up, as in 12 o'clock.

 

Try it at 10-11 o'clock... That should trigger it sooner keeping the failsafe from tripping.

 

very informational thread...keep it coming!

 

Richard - are you still working to improve the response time of the flow sensor or do you think you have reached the point where it is now fast enough.

 

So what are the differences between the V8, V8a and V9 junction boxes and what were the concerns people were having with the older units?

 

from a post about 5 posts up ----

The first version of the v8 (~2s grace) never have those problem. Then came the conerns expressed by users. So, we reduced the grace period to 0.06mS. (Oct 07 to April 08). On the V8a and v9, we have increased the "grace period" to ~125-200mS. Just have to wait and see.

So to sum it up

v8 (produced before OCt 07) - the early v8 boards have a 2 second delay, this gives the flow sensor plenty of time to react. You should not have any problems with this system although some consider a 2s grace period to be a bit long.

v8 (produced Oct 07 to April 08) - boards have a .06ms delay and as such sometimes the flow sensor can not respond quick enough to tell the DDS3 that flow is enough. As a result sometimes the system will trip the failsafe prematurely.

v8a & v9 - these boards have a grace period of 125 to 200ms. This is considered the least amount of delay possible to still allow the flow sensor some time to react. This version of boards should not exhibit any problems.

 

The development of the flow sensor will cease when the time constant hits 1 nano second.

 

Well that should keep you guys busy for a while