Hi there,

I've recently swapped what I believe to be a semi closed deck EJ25 into my 54 plate Blobeye WRX and have been mapping with the Carberry 4.2 ROM.

I was just wondering if anyone would have any suggestions as to the following issues I've been having:

1) There seems to be a judder that develops at light throttle (just cruising, no acceleration) at around 2k-2.6k RPM - I've adjusted my throttle enrichment values but this doesn't seem to make any difference.
2) The car really struggles to idle properly, at times it cuts out completely - I've been running a little (0.08v) more of a throttle opening at idle to try and cure this, but to no avail.

I'd really appreciate any suggestions on this, as I've noticed that the car is going through more oil than it should, I'm beginning to thing that there's something not quite right internally with the engine, possibly a headgasket...

Another thought I've been having is that the juddering could caused by the standard FPR that I'm running (I'm going to fit a Turbosmart one next week hopefully).

I've replaced the spark plugs, coils and front lambda sensor to see if this makes a difference but the car behaves exactly the same.

My mods are as follows:
- VF35
- 736cc injectors (recently flow tested - they are decapped STI pink injectors so I've been running the standard latency values in the map)
- TGV deletes (I have left the connectors unplugged and I've been running the TGV deletes within the map also)
- Parallel fuel conversion using the standard rails
- Walbro 255
- Oil catch can set up (but not feeding the oil back into the sump)
- Fuji Racing exhaust headers

Any thoughts would be much appreciated!

VFR22B

 

Whilst I remember, I'm also running Brian Crower stage 1 cams.

 

Just to update this post, I kept on working on the idle problem but apart from having briefly cured the problem by opening the throttle butterfly to 0.62V at idle, the car then returned to behaving as normal. I couldn't find the solution to the constant low speed juddering and the car started to demand more fuel at idle and was running terribly.

At this point I gave up with the mapping and removed the engine and got it delivered to an engine builder. A few weeks later I received a call from the engine builder explaining what he had found.
The ringland in piston number 3 had cracked and broken, hitting the cylinder head at some point, resulting in some light damage. In addition, there seemed to be a lot of sludgy oil in the engine - I had been using Millers Trident 10w40. The pistons in the engine were Cosworth pistons.

I'm now getting the engine rebuilt and hopefully it should be in the car in a couple of weeks. Out of interest has anyone had any similar experiences with Cosworth pistons?

Cheers,

VFR22B

 

I think there have been a couple of threads about those particular pistons.

 

Cosworth pistons in Subaru's are the worst forged piston you could fit, for noise & reliability.

 

Thanks both, I’ll buy a set of Omega pistons as they seem to be a reliable piston from what I’ve seen on here.

I’ll update once the engine is back in the car.