hi there,

did you ever figure out what was wrong w/ your car not being able to build boost/make power past 15/16psi?

 

https://my350z.com/forum/forced-indu...ally-over.html

By the way Brian, if you read this, I think the reason power drops off if you crank up the voltage is that the same line used for the coils is tied to the intake cam solenoids. As you turn the voltage up, those slowly start to turn on, resulting in abnormal variable valve timing. That's just a theory though. I think keeping it to a steady 15V or so doesn't have any impact. I installed the BAS but it had no positive impact. No negative impact at 15-16V either. Did not try to go higher to see if power would drop...

 

I'm not following your logic, rcdash. The wire we tapped in to doesn't appear to have anything to do with cam timing solenoids if I'm looking at the correct wiring diagram (it's obviously been months since we installed this, but it's page EC-582 of the 2003 FSM)...Brian made a ton more power at higher RPM with the boost a spark than without it... His power doesn't drop off with the KB BAS...

Which wiring diagram are you looking at that is showing the line we tapped in to having anything to do with the cam solenoids?

 

I think what he's referring to is when we crank up the voltage on the BAS. Remember when we were on the dyno and turned the BAS past 30 and started to lose power again and the the dyno guy thought that maybe the BAS was draining the system too much?? If the wire we tapped does indeed also feed signal to the cam solenoids than this is feasible.

 

Looks like Im going to follow my own sugestion and doing this to the G. Did you every verify the they cam control shares the same power supply feed as the coils? Id rather not juice them if I dont have to and could easily rewire it so the coils are isolated. What voltage was the 30 setting supplying the coils?

 

No, as far as what Neal and I could discern, they do not share the same power supply. Not sure what voltage the 30 setting was getting us, but even on 10 the car made the same power. It wasn't until we turned it way up that power started to drop off.

 

so what was the problem, ? is the utec having a bad ignition driver, transestor ?

 

I have attached a single page from the FSM for my 2004.5 G35 5AT coupe. It clearly shows that the power line is shared (see red arrow!). Other model years/cars may be different. I didn't trace the power wire through the entire harness but the wire color was the same at the ignition coils and where it emerged again for the solenoids as far as I could see.

In regards to the voltage, I measured it using a resistor divider network and my innovate logging gear and the BAS does work. Unfortunately, turning the dial 1/3 of the way up does nothing (temp dependent since the dial is just a potentiometer). Once you hit that magic point, the voltage increases quickly all the way up to 21+ volts with the dial to the far right. The intake cam solenoids are driven off a ground pulse and the power line for the ignition coils feeds the top of the solenoid coil (in my FSM). If you increase voltage a few volts beyond battery voltage then the coil will start to energize and the solenoid will activate. I didn't try to push voltage beyond 16V. At 16V it did nothing for me on the dyno. One thing the whole exercise taught me though is that the voltage feeding the coils does indeed drop on the dyno as rpms increase. My base voltage I believe was 13.4 volts and it would drop to 11.9 at redline. With the BAS, it stayed steady throughout the dyno pull at whatever setting it was at. No change in power for me though (with a Haltech).

I do believe the BAS will be helpful for UTECs and perhaps for W/M injection in general.

 

The problem was spark. I installed the KB BAS and saw a dramatic increase in top end power. It still fell off a bit but that was due to the stock cams and stock plenum. I now have a Cosworth IM and it makes good power all the way to 7000rpm.

 

ok, i wana know how ...

why did the spark became weak, is that becouse of the UTEC or the stock ECU ???? or the coils ????

i dont think its the stock ECU cuz if any thing gets bad its allways after the ECU, and over there comes the UTEC.

we really need to clear this here.

 

I'm of the opinion this must be a utec issue. I believe the people that have had this issue or resolved it with a BAS all used a UTEC.

I constantly go back to others running more boost (and more air volume) don't have this spark issue.

We gotta have someone with this prob pull some power readings at the coils and compare it to stock and other setups.

tom

 

Almost everyone who seeing an improvement with a BAS has a UTEC. That leads me to believe it's the UTEC that supplies a weak ignition signal.

If someone wants to test the voltage difference, be my guest. My car is obviously getting better juice to the coils now so I'm not going to chase the issue any further.

 

Well since the coils (over spark plugs) are actually driving the spark, I would theorize that at high rpm the UTEC transistors are simply not pulsing ground well enough. The UTEC has a history of grounding issues and I believe this particular issue is just another manifestation of poor grounding/ground design within the unit. Bumping up the power transistor power signal just drives the transistor harder even if ground is not really 0 volts.

 

yeah this is true.

 

i llove my Haltech

 

Then why are you so worried about this issue with the UTEC.

 

I didn't ignore this post, I just want to check my FSM before I post a response...

 

i have a customer having this issue

 

Get them a BAS or a different engine management. End of story.

 

thanks.

but that BAS is really doing a great job