Removing N249 valve - How To Guide

cuprabaz

Racing 2020VT
Jun 22, 2004
2,357
1
Aberdeenshire
Thanks.

That would be telling! :bleh:

The resistor block is behind the coolant battle, you can just see the red and black wires in the pic.
 
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Shock_Xe

Guest
could I not 3x 50w resistors at 100ohms each and connect them serially??
 

Sim

who?
May 24, 2001
1,700
0
Budapest, Hungary
www.ignitron.net
50W resistors!? They are surely quite big :).

BTW if you connect them serially, their resistance will add up together, resulting in 50W but 300ohms - ECU will report a faulty N249 valve.

Connecting them paralelly, will yield 150W but 33.3Ohms (desired resistance). Though 150W is very very extremely much :)
 

Shock_Xe

Guest
Sim said:
50W resistors!? They are surely quite big :).

BTW if you connect them serially, their resistance will add up together, resulting in 50W but 300ohms - ECU will report a faulty N249 valve.

Connecting them paralelly, will yield 150W but 33.3Ohms (desired resistance). Though 150W is very very extremely much :)

I thought desired resistance was 300ohms??

So could I use 5x 10W W/W 68R Wirewound Resistor

"A range of high quality wirewound resistors sealed ina high insulation ceramic block. The block is heat and moisture resistant and non-flammable. The resistors are low noise, very stable and have an overload capability of ten times the rated power for 5 seconds. Value 4k7 is metal oxide film and has an overload capability of five times the rated power for 5 seconds"
 
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Sim

who?
May 24, 2001
1,700
0
Budapest, Hungary
www.ignitron.net
5x10W 68R paralelly would mean 68/5 ohms = 13.6 it is not good either.
5x10W 68R serially would mean 68*5 ohms = 340 whisi is also not good ;).

Aim for 30Ohms (30-50W).

Lets say I've used 9x (5W 270Ohms) = 45W 30Ohm. -> 5W*9 + 270Ohms/9
 

Shock_Xe

Guest
Sim said:
5x10W 68R paralelly would mean 68/5 ohms = 13.6 it is not good either.
5x10W 68R serially would mean 68*5 ohms = 340 whisi is also not good ;).

Aim for 30Ohms (30-50W).

Lets say I've used 9x (5W 270Ohms) = 45W 30Ohm. -> 5W*9 + 270Ohms/9

I dont understand this :(

This is the choice of resistors i was looking at, any feedback appreciated here
 

Sim

who?
May 24, 2001
1,700
0
Budapest, Hungary
www.ignitron.net
But it is so simple! :)

- If you connect (two) resistors serially, their resistance will add up together. Lets say connecting 2x68R together, it will be the same as using a single 136R.
- If you connect (two) resistors paralelly, their resistance will divide. Lets say connecting 2x68R paralelly, it will be same as using a single 34R.

The aim here is to get something (really anything!) which has 30Ohms resistance and can handle some load (dissipate heat).

The most accurate (from the link above) would be to use 11 pieces of 3W 330R connected paralelly. That would yield 33W 30Ohms, but i guess it would take up lots of space (11 resistors).

I also would suggest using 7 pieces of 7W 220R connected paralelly. That would yield 49W 31.42 Ohms.

Both solution is close to the resistance of the original N249 valve.

Using 3x 10W 100R connected paralelly may also work, as it would be equal to 30W 33.3R, but it is already 11% higher than 30Ohms, i don't know if ECU would report that as a faulty N249 valve.

You should have mentioned these resistors earlier, i'd have prepared and sent you one.
 

Shock_Xe

Guest
Sim said:
But it is so simple! :)

- If you connect (two) resistors serially, their resistance will add up together. Lets say connecting 2x68R together, it will be the same as using a single 136R.
- If you connect (two) resistors paralelly, their resistance will divide. Lets say connecting 2x68R paralelly, it will be same as using a single 34R.

The aim here is to get something (really anything!) which has 30Ohms resistance and can handle some load (dissipate heat).

The most accurate (from the link above) would be to use 11 pieces of 3W 330R connected paralelly. That would yield 33W 30Ohms, but i guess it would take up lots of space (11 resistors).

I also would suggest using 7 pieces of 7W 220R connected paralelly. That would yield 49W 31.42 Ohms.

Both solution is close to the resistance of the original N249 valve.

Using 3x 10W 100R connected paralelly may also work, as it would be equal to 30W 33.3R, but it is already 11% higher than 30Ohms, i don't know if ECU would report that as a faulty N249 valve.

You should have mentioned these resistors earlier, i'd have prepared and sent you one.

Im trying to simplify it as possible, i.e. as little ammount of resitors as poss

will try 7x 7W 220R... will skip the 10w ones as i only wanna do this once
 
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