Bosch 1600cc with NO Resistors?

[lugnuts]

Hello, I have a v3 ecu running Bosch 160cc, 5 ohm injectors.

Before it was on 1000cc low-z and a Honda resistor pack.

The resistor pack just failed, can I delete the resistor (can I use the Bosch 5 ohm injectors directly to the ecu?)

If yes, is this a supported method?

The engine turns 8000+ rpm and the fuel is E85, so the injectors/drivers will be worked hard to 80% duty cycle.

Thanks, Kevin

[PeepPaadam]

Yes, I recall Marcell had suggested using them that way and I've used also, no problems whatsoever.

Just use them as regular saturated injectors.

[lugnuts]

Success. I removed the resistor pack after a baseline dyno pull. I had to remove a ton of fuel in the calibration afterwards! The car runs well and we now have more duty cycle to play with. We made 582 whp on E85 with a chipped compressor wheel. Thanks for the reply.

[GintsK]

Little offtopic.
Currently I have Audi with 2200cc Low-Z 2Ohm injectors. No any hope to use resistors. Even twice smaller than calculated.
Injectors simply not opening time to time.

My solution was JBperf peak-hold boards.

Gints

[lugnuts]

I tried using an FJO injector driver on this car last year, when it had 2 ohm 1000cc injectors.
The ecu would randomly go crazy and lock open the injectors, flooding the engine.
The only other thing it could have been was, I was logging Air/Fuel from my Autronic analyzer into Analog Ch5. I never did figure out which was which, I couldn't risk using the customer's engine for a guinea pig any more that it already had been.

[MWfire]

I use PWM with active 30V flyback without problems.

[GintsK]

Beauty of JBperf board is no PWMing. So no noise.

[GintsK]

I hope some time in future VEMS will officially allow peak-hold strategy on-board...
It IS necessity if we want to see hi-power cars running VEMS.

[MWfire]

Beauty of JBperf board is no PWMing. So no noise.

nope, that board is PWM.

[Sprocket]

Beauty of JBperf board is no PWMing. So no noise.

nope, that board is PWM.

I am pretty sure Jean's boards are peak and hold as described

[GintsK]

No PWMing. You can read about IC used on this boards here: http://www.national.com/ds/LM/LM1949.pdf

again my offtopic. Using this JBperf boards yesterday I was able idling at 850rpm or even lower with 5x2300cc low-z. E85. And AFR - stable 1.0!! Audi 20VT.

[MWfire]

No PWMing. You can read about IC used on this boards here: http://www.national.com/ds/LM/LM1949.pdf

again my offtopic. Using this JBperf boards yesterday I was able idling at 850rpm or even lower with 5x2300cc low-z. E85. And AFR - stable 1.0!! Audi 20VT.

Loock again
http://www.national.com/ds/LM/LM1949.pdf
page 10, figure 6 . It's pwm to hold 1A thru injector.

[Sprocket]

Perhaps I do not fully understand what true 'peak and hold' drivers are

It is my understanding that Peak and hold, in each event, will allow the saturated current to rise rapidly to a set limit. Once at this current, it remains for a pre set time, determined by a resistor. After this time has elapsed, the current is clamped down to another pre set limit again determined by a resistor and held there untill the end of the event. If the current never reaches the saturated limit, the current is never clamped during the time it is applied. It is my understanding that the peak and hold driver limits the current by sensing it.

What is a true peak and hold driver? and how does it limit the current without PWMing?

Im not trying to be funny about this, I only want to understand correctly how these are suposed to work

[GintsK]

No PWMing. You can read about IC used on this boards here: http://www.national.com/ds/LM/LM1949.pdf

again my offtopic. Using this JBperf boards yesterday I was able idling at 850rpm or even lower with 5x2300cc low-z. E85. And AFR - stable 1.0!! Audi 20VT.

Loock again
http://www.national.com/ds/LM/LM1949.pdf
page 10, figure 6 . It's pwm to hold 1A thru injector.

May be I don't understand correctly? IMO in separate chapter on page 9 described  special case how to use LM1949 for reducing heat but with radio noise (RFI) as result of PWMing. Fig 6 on page 10 relates to this special case. Normal mode switching diagramms is on page 7.
Additonally on first page we can read: no RFI radiation!

[Sprocket]

No PWMing. You can read about IC used on this boards here: http://www.national.com/ds/LM/LM1949.pdf

again my offtopic. Using this JBperf boards yesterday I was able idling at 850rpm or even lower with 5x2300cc low-z. E85. And AFR - stable 1.0!! Audi 20VT.

Loock again
http://www.national.com/ds/LM/LM1949.pdf
page 10, figure 6 . It's pwm to hold 1A thru injector.

May be I don't understand correctly? IMO in separate chapter on page 9 described  special case how to use LM1949 for reducing heat but with radio noise (RFI) as result of PWMing. Fig 6 on page 10 relates to this special case. Normal mode switching diagramms is on page 7.
Additonally on first page we can read: no RFI radiation!

Right then, I have read the whole document, and while I dont fully understand the technicalities of the whole thing, I do understand that we both were indeed right that there is no PWMing happening on Jeans' Peak and Hold boards. While the LM1949 chip can PWM in a switching circuit, it is not recomended due to the RFI noise that it generates, which is the whole point of the peak and hold driver in the very first place.

I now understand that the 'hold' period, disipates the current rather than switching it (PWM)