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Discussion Starter · #1 ·
Hi All,

I've been chatting to a few people regarding some odd issues I've been getting since getting a new Timing belt. This was fitted by my local garage and came back flat, not boosting much at low RPM and going completely flat at high RPM.
I've adjusted the timing using a HT lead in the coil to the spark and got exactly 15 degrees but no joy. Advancing to 20 degrees seems to help but still no fix.

Something that's been suggested to me is to find someone with a CAS for an RB25det to see if this is causing the issue as they have been known to be a bit temperamental.

Is there anyone in the Berkshire UK area able to help out and let my try another CAS before I go spending a lot of money on a new one?

Thanks in advance for any help/advice.

A.
 

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KH3 ECR33
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Just an FYI on the CAS on the RB25's, there are two of them. Mitsubishi make the CAS for the series 1 RB25 and Hitachi make the CAS or the Series 2 RB25's and NEO's. They have different drives too that obviously fit different drives on the exhaust cam. Hitachi CAS has a off-centre straight slotted drive and the Mitsubishi CAS has a star shaped drive. Hope this helps.
 

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Discussion Starter · #3 ·
Just an FYI on the CAS on the RB25's, there are two of them. Mitsubishi make the CAS for the series 1 RB25 and Hitachi make the CAS or the Series 2 RB25's and NEO's. They have different drives too that obviously fit different drives on the exhaust cam. Hitachi CAS has a off-centre straight slotted drive and the Mitsubishi CAS has a star shaped drive. Hope this helps.
That's interesting as I know I have a series 2 N reg Gts-t and the logo on the CAS is Mitsubishi with a central drive.

Attached images showing the CAS and engine.

Could you mean it's different from the Det version as I've not heard of different series of the RB25-Det

Thanks.
 

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If in doubt...
KH3 ECR33
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325 Posts
It may just be the very late RB25DET's that have the Hitachi CAS's fitted, just before the R34 came out with the NEO. I have two engines here, out of two Series 2 33's. The one that came out a 1996 chassis car has a Mitsubishi CAS like the photo and the other engine out of a late 1997 chassis has a Hitachi CAS. They obviously both have different exhaust cams too, to support their respective CAS drive.
There are also a few differeces between Series 1 and Series 2 RB25DET's, in the R33's anyway from my experience. The main differences are:
1. The Spec 1 25 has an external ignition amplifier for the coil packs but the Series 2 has the amps integrated into the coil packs.
2. The Spec 2 has a ceramic turbine wheel in the turbo whereas the spec 1 has a steel turbine wheel.
3. AFM's have different part number and different colour stickers.
4. Engine ECU's have different part numbers too, largely to support the wiring for the different coil packs.
5. CAS's are different too but I think that that wasn't the case for all Series 2 25's, only the late ones.
 

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Discussion Starter · #5 ·
Hi V.

You learn something new everyday! I knew about the coils and afm but not the rest.

Out of interest, does anyone know if the mitsubishi cas came standard on any other cars?

Thanks.

Thanks
 

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Discussion Starter · #6 ·
Quick update.

Replaced the sparks today and felt a little improvement but still bogging down at high RPM and overboosting.
Hoping to get a compressor soon as my airbrush compressor doesn't have enough puff to pressurise the system to check for leaks.

Another quick question that I can't find a definitive answer for, I ordered new gaskets for the rocker covers and half moon seals. The company sent me gaskets labelled RB26. Would these still fit?

Thanks.
 
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