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Author Topic: converting from cam angle sensor to crank angle sensor  (Read 991 times)

jade501

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converting from cam angle sensor to crank angle sensor
« on: April 27, 2011, 08:09:45 PM »
has anyone done this on a rb25det neo as i have been talking 2 raceshred and they where saying best thing to do as the rb25det neo cam angle are usless and change degrees to often

the__berg

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converting from cam angle sensor to crank angle sensor
« Reply #1 on: April 27, 2011, 08:23:03 PM »
i think andre at speedtech can modify your factory cam angle sensor with less points of measurement.

Looney_Head

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converting from cam angle sensor to crank angle sensor
« Reply #2 on: April 28, 2011, 08:57:57 AM »
Shred has done this too.

have you had any issue with the cam sensor yet?
god is just an imaginery friend for grown ups

jade501

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converting from cam angle sensor to crank angle sensor
« Reply #3 on: April 28, 2011, 04:24:50 PM »
no but i would rather fix before it does go wrong

gtsr

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converting from cam angle sensor to crank angle sensor
« Reply #4 on: April 30, 2011, 12:21:57 AM »
R34 NEO RB25DET is known to wear out front of exhaust cam when cambelt is loose. The play / wear that is created (because of the loose cambelt) between CAS, exhaust cam can cause the base timing to wander.

Off crank has been done on GT300 racecars in Japan. But were running a Motec ECU.

But CAS is supposedly better than taking off the damper. Have a look at the signals that are created by both.
« Last Edit: May 06, 2011, 09:53:29 AM by gtsr »

GETLOW

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converting from cam angle sensor to crank angle sensor
« Reply #5 on: May 06, 2011, 01:59:03 AM »
Taking crank timing off the cam is never going to be ideal. Even cam chains streatch and they have harmoics that cause the length to go longer or shoter, thus changing the position the engine your ECU belives the engine is at.
You will need an aftermarket ECU to run it.

You buy a Link 24 tooth medium size trigger wheel and get that machined and pressed on your your crank pully. and then you will need to install a reluctor sensor with in approx 1-2mm of the tooth.
You also need to replace the disc in the Cam angle sensor with a 24 tooth disc with a 1 tooth sinc (the 1 tooth sinc is used)

We did just a CAS disc and it improved it, but it still wasn't good enough (ECU was seeing the 8000rpm limiter at 6300) so we fitted the crank trigger disc and the timing now sits bang on. It also shows up in the data logging when you look at the RPM rate on a hub dyno
We won't tune an R34 motor with a Link with out the above mods, as we are after performance and reliability with good drivability. so were not going to take any short cuts they may or may not work.
1JZ VVTI R33 using a custom RB25DET gearbox (almost running)

Shred Motorsport
67 Pharazyn Street
Lower Hutt, Wellington
http://www.SHREDMOTORSPORT.co.nz
(04) 569 7469

westybob

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converting from cam angle sensor to crank angle sensor
« Reply #6 on: May 06, 2011, 06:56:34 AM »
Geoff what is the approximate cost of the mods you have described above and would you say it was necessary (or a good idea or no advantage)  for an RB30/25 running a max of 6500 rev/min with a G4?

gtsr

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converting from cam angle sensor to crank angle sensor
« Reply #7 on: May 06, 2011, 11:03:36 AM »
That's interesting, thanks for sharing that info Getlow.

GETLOW

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converting from cam angle sensor to crank angle sensor
« Reply #8 on: May 07, 2011, 10:50:36 PM »
The R32/R33 style crank angle sensors are 50x better then the neo crank angle sensors with holding steady timing.

Its hard to say if its necessary, as we havn't had to (considered it an issue to require doing) do it on anything else apart from half a dozen Neos, and 1 SR20DET. If you have uprated valve springs then it could be worth your time doing.

The cost is around $800-1000 depending on how hard the bracket to mount the sensor is to make as you get some variances, This covers all brand new parts, fitted and installed.
Rough break down is (prices arn't exact)
CAS disc $100
Crank Trigger disc $140
Bosch VR reluctor sensor $160
cost for engineer to fit crank trigger disc to crank pully $80
Labour and materials 200-500 (usually around 350)

Its much easier to do with air con removed, as you Can't put it on the back of the crank pully. I'm going to look in to finding sombody to cut the 24 teeth in to a factory crank pully next time we have a request for one done as this would allow us to build a bracket that will work for 90% of applications.
1JZ VVTI R33 using a custom RB25DET gearbox (almost running)

Shred Motorsport
67 Pharazyn Street
Lower Hutt, Wellington
http://www.SHREDMOTORSPORT.co.nz
(04) 569 7469