Jensen

2008 Focus ST500 Acceleration issues

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Hi There

Car: Focus ST500 2.5T

Year: 2008

Mileage: 32,000

MODS: Full 3" scorpion exhaust system with De-cat from turbo back, Rad tec Intercooler, Bailey dump valve, K&N cold air induction kit, Dream science tuning Module with MOD X map 

DTC's: None present

I very rarely drive it, It was off the road for last 6 years but recently put through its M.O.T for some summer fun

A few Issues don't know if they are related

Issue 1: Oil pressure reading 5 bar ( Is this normal ) when cold at idle, when warm reads 3 bar at idle. Normal driving reads between 3.5 - 4 bar heavy acceleration gauge goes straight to 5 bar - Is this normal behaviour as I cant remember it ever reading up to 5 bar of pressure before (maybe it was) ?

Issue 2: Acceleration/Power issue between gears at any style of driving, Noticeable when changing gears for a split second or two it dies out then picks up immediately and tone of exhaust is deeper when this happens, Car accelerates fine with no hesitations at all when cold - If pulling off fast from a stop start it dies out for a split second then picks up & then traction cuts in then it dies again then picks up instantly again , Car accelerates really well with lots of power/boost after this split second power lose - MAF, MAP or Boost solenoid sensors issues maybe? No DTC's present

Issue 3: Clutch slipping under heavy acceleration - There was a recall for bad clutches & wheel bearings fitted to some ford models back in 2007/2008 and my car fitted into this category as I had 2x front wheel bearings replaced by Ford back in 2010 F.O.C, Plus the extra BHP applied due to engine mods isn't helping this clutch issue but can anyone recommend a good clutch / DMF set up to take more BHP ?  Would like to stage 5 tune it to 450 - 500 BHP here in the next while so would like to prepare for this now with a good clutch kit that can take the extra pressures 

 

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To answer two of your points:

1) Our RS does this, oil is thicker when cold so needs more pressure to push it round and same under heavy acceleration. 

3) Id’ve thought the RS clutch would be just fine for this, even up to 450-500bhp?

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issue 2, bit of a longshot. On some (most?) cars, if you disconnect the MAF the car will still run using a default average maf level. So if you disconnect the MAF and it runs better then it would suggest it is likely to be a MAF problem. I recall my bothers' Audi TT having issues similar to what you describe and that was the MAF sensor.

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18 hours ago, dtulip8 said:

3) Id’ve thought the RS clutch would be just fine for this, even up to 450-500bhp?

I don't think the Op has an RS clutch fitted to his ST500, or I can't see it stated in his post at least.

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41 minutes ago, 1979Damian said:

I don't think the Op has an RS clutch fitted to his ST500, or I can't see it stated in his post at least.

I would say he is recommending the rs clutch cos the guy asked for recommended ones.

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5 minutes ago, F0CUE said:

I would say he is recommending the rs clutch cos the guy asked for recommended ones.

Ah, that makes sense 😁 Just goes to show how a simple sentence can be interpreted in more than 1 way when written not spoken.

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Yeah I meant he should fit the RS clutch 😅! Bloomin’ lack of intonation on the internet!

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