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Turbo Boost issues

18K views 19 replies 11 participants last post by  rik-renovations 
#1 ·
Hi,

For about the past 18 months I've had some weird issues with the performance of my R26.r.

Symptoms include:

1. Boomy exhaust noise
2. Disappearance of whoosh in cabin
3. Lack of power
4. Increased full consumption
5. Weird gaps in exhaust sounds when accelerating hard

I've had it into Renault three times now and they've done the following:

1. Replaced knock sensor
2. Replaced solenoid value
3. Replaced oxygen sensor
4. Replaced injectors
5. Told me I'm just used to the car so go away (not directly of course)

Now that the warranty has expired I've taken the car to a specialist whom within 10 minutes agreed the car has an issue. On the dyno the car made 200hp as standard and 216 with the stage 1 map loaded. Clearly something is wrong. I would have noticed an instant loss of so much power so I'm thinking the problem is one that has slowly become worse with time.

The guys did the following to diagnose the problem:

1. Boost leak test
2. Bypassed solenoid value
3. Removed/bypassed actuator (should have given crazy boost but nothing).

I think boost was maxing at 0.3 bar maybe.

They've told me until they can have the car for a 1-2 days it might be the following:

1. Clogged cat
2. Mal-fuctioning wastegate
3. More serious turbo issues

As I'm not hugely knowledgable regarding engines I thought I'd ask for some advice here first. Either tomorrow or Monday I'm having a decat as this is the cheapest of the possible causes to remedy. Obviously if that's not the issue the costs will rise quite quickly.

I've been thinking of going down the forged engine route with a larger turbo etc. So I'm thinking I'd rather put the money fixing the current issue into upgrading the car properly.

Does anyone have have any suggestions and as the problem was investigated by Renault well before the warranty expired should I speak to Renault UK ?

Thanks,
Matt
 
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#3 ·
Thanks Paul, I had the guys call you but you were two weeks on the decat pipe so went with k-tec instead as I really need the car running properly. I'll PM you about the forged option though.

If it is the cat why isn;t the ECU registering a fault ?

Matt
 
#9 ·
Hopefully I'm collecting it today. The ball link from the wishbone to the wheel hub had seized and they stripped it when removing it. Typically no one really cars R26 parts for same day dispatch so I've had to wait. The turbo has been inspected and is in perfect working order.

It might have been the cat after all but from a quick visual inspection it looked OK.

Matt
 
#10 ·
Could well still be the cat.

Often if it's a mechanical fault it is difficult to find as you always tend to go with electric components first now a days.

If it isn't the cat I would personally contact RUK and explain your situation. I would imagine as your complaint has been ongoing they will either make sure it gets sorted for you free of cost off will ask you for a contribution depending on what they find to be the problem.

Have you changed the intake filter recently?
Has it been driven with the mass air flow sensor disconnected at all?
 
#12 ·
There's a lot of possibilities that's all.

It was actually my dad that had an impreza sti which was 80bhp down on standard. He had replaced loads including cat, checked timing, etc etc. in the end it was the over looked aftermarket air filter which was clogged but looked clean. After a new filter and a remap he gained circa 100bhp. It was amazing how much difference it made which I'm sure you can imagine!
 
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