Hi All

im on my second R52S which I got for cheap money as it had a few issues that needed sorting. On picking the car up, it didn’t seem as quick as the previous one. I wasn’t concerned as I knew there was work to do and that may well cure it.

I’ve sorted out the other issues on the car now and I’m looking at why it seems down on power. I’ve fitted a 15% reduced pulley, colder plugs, serviced the supercharger, fitted a rooster racing modified bypass valve, new aux belt, rear main oil seal, flywheel and clutch, 380cc injectors and had it remapped by Adrian.

Even with these mods it seems slower than the first R52S. Adrian reckoned I had a boost leak, which I put down to the pipe from the manifold to the fuel rail regulator being off. Refitted the pipe and it blew off again, so I replaced that with a new one.

the supercharger boots are not split so I’m running out of ideas.

The car doesn’t misfire, although it does pop a bit on over run which it always has done. It doesn’t seem to use oil or coolant.

im planning on carrying out a compression test and taking off the intercooler to check it for leaks / cracks.

Has anyone else had a similar issue?

 

I just went through something similar, however, my car would go between just being low on power to sometimes seeming like it was going to stall out. No check engine light, no codes.

I just replaced the fuel pressure regulator and fuel pump because 1) it seemed like a fueling issue and 2) both parts were original on my car, so nearly 20 years old.

That was the fix. My car is happily running at full power now!

 

I'm wondering if mine is similar, but I'm on my first R53 (R52S actually) so I have no point of reference - and also I have a 2017 Civic sport hatch that has a turbo motor tied to the world's only good CVT - so it's quick, and I wrote off my "this MINI feels slower than my Civic" to "it's an older car and the Civic is quick", HOWEVER...

...I just finished installing a 17% pulley (and colder NGKs) and an ATI crank damper pulley/tensioner/belt for maintenance reasons, and it doesn't feel like it made a difference. It did make the supercharger whine more prevalent, so it's surely spinning the charger faster. It's "I can maybe feel a difference", like when you put a cold air intake on a car. A few extra HP. That, I have a point of reference for. Relative reference.

So my first thought on my test drive today was "Maybe it's leaking boost". Is that a common issue?
Or that blow-off valve - is it that it gets stuck open, so the boost all escapes?
This car is new to me (2 months now). so I'm not even familiar with the charge pipe routing yet - but sounds like I should get into inspecting it. With the packaging of the MINI engine bay though, I suspect it might be difficult to do that visually. I bet there's a thread here somewhere on troubleshooting that...
I wonder if we're both facing the same thing?

 

I’ve just ordered a cheap boost gauge off Amazon for testing purposes. Mine has had a bypass valve and the pipe from the manifold to the fuel pressure regulator already, and I’ve tried a different intercooler and boots.

A compression test showed good readings across all cylinders, and they were all within 10% of each other so I don’t think I’m looking at worn rings. It’s either fuel related or has a boost leak. I would expect a misfire if it was fuel related?

The car doesn’t misfire, however it does try to pop a bit on over run, which my last one didn’t so I wonder if that’s related. Hopefully the boost gauge will give a clue as to if it’s making enough boost.

 

sorry, meant to mention when I put a 15% pulley on my last R52S it was noticeably different. It might be worth having a look to see if the pipe from the manifold to the fuel pressure regulator on the rail has come off one end?

 

that’s the next step I think. If the boost pressure is there I’ll throw a fuel pump on it

 

So, I fitted the boost gauge yesterday for testing purposes and I’m not making much in the way of boost. There’s plenty of vacuum so I’m guessing I don’t have a leak anywhere.

im going to pull the vac hose off the bypass valve and see if that improves things. Failing that I’m thinking the supercharger is worn internally

 

So, finally got it sorted. The boost gauge only showed 13 psi at WOT, and as I was pulling hood vacuum I thought that the supercharger might have an issue.

Threw a different one on this morning and power is restored 👍

 

What did you end up throwing on that fixed the issue? A BPV or supercharger (kind of a pricey thing to just "throw on" )? My mini might have the same problem, hoping it's just the BPV or, better yet, the BPV gasket.

 

I fitted a BPV first and it made no difference. I plumbed a temp boost gauge in and was getting great vacuum and 0.9 bar of boost, so I presumed that I wasn’t leaking boost, I just wasn’t making enough of it from the old charger.

I was lucky as I knew where there was a scrap car locally with a Teflon charger, which I paid £100 for, however I had to take it off the scrap car myself.