One down, one to go (maybe)

[srhutch]

Spot the difference on my car right to left from the centreline

Right, so a little while ago I picked up these from a well known forum member. They had been gutted

One had a broken clamp, but I had already picked a set of clamps up even before these boxes came up because it's a known issue.

So a few months ago I started the restoration of the boxes

Resulting in this, ready to go

A chance to use my new acquisition (2 months ago). It came with a free house :roundel:

I only used around half the pit, it's 12 foot line, 3 foot wide and 6 foot deep as you can see by my step ladder down it.

It was obvious the clamp bolts were not going to come undone so I went round all the other bolts in turn to make sure I wasn't going to end up with a problem. Got there in the end, but one bolt did sheer which wasn't expected as it was coming out quite easily. Anyway bolts on clamp cut with hacksaw and then used a dremel to remove my broken clamp. The one of the box had already been removed.

So end result after a couple of hours

Conclusion. I can tell the difference even with only changing one box. I also think one box might be enough, with my GruppeM. I will get other members feedback soon.

Question is do I paint the other one black, or remove the black and polish them up.

If I only fit one box I might offer the other up as a swap to local member. I would want a spare one in case I ever did the full monty.

 

[Bing]

Looks good Steve... I might be willing to swap with you. Have you painted both the gutted boxes black ?

I shall judge the noise next month

 

[Number5]

Yeah, Looks good Steve and a very useful Pit too

PS Did the back box come off the same Romanian Box Van as the number plate ? :evil:

 

[exdos]

Fitting just one gutted silencers would be a bad idea. Gutting silencers permits a greater flow of exhaust gases, which permits the engine to ingest more air/fuel. Although there is a cross-over pipe connecting the pipes from the two manifolds, there's the possibility that three of the cylinders connected in line to the gutted silencer might flow more freely than the cylinders connected to the OEM silencer, which might cause fuelling problems.

 

[srhutch]

Fitting just one gutted silencers would be a bad idea. Gutting silencers permits a greater flow of exhaust gases, which permits the engine to ingest more air/fuel. Although there is a cross-over pipe connecting the pipes from the two manifolds, there's the possibility that three of the cylinders connected in line to the gutted silencer might flow more freely than the cylinders connected to the OEM silencer, which might cause fuelling problems.

Was going to ask about running issues, but forgot.

Would you expect an EML light if there was an issue?

 

[buzyg]

Looks good. 8) What does it sound like?

 

[cj10jeeper]

Fitting just one gutted silencers would be a bad idea. Gutting silencers permits a greater flow of exhaust gases, which permits the engine to ingest more air/fuel. Although there is a cross-over pipe connecting the pipes from the two manifolds, there's the possibility that three of the cylinders connected in line to the gutted silencer might flow more freely than the cylinders connected to the OEM silencer, which might cause fuelling problems.

My sentiment exactly. I would never put a system out of balance.
Swap neither box or both..

 

[srhutch]

Looks good. 8) What does it sound like?

Think I would get and ASBO with both fitted with the GruppeM :lol:

Bit of drone around 2K under load which was Mr. Truman's issue. I can live with it. If fueling is an issue I will put both on. But if the X pipe is joined in the middle I can't see how it would be affected as it would be half and half.

 

[srhutch]

Fitting just one gutted silencers would be a bad idea. Gutting silencers permits a greater flow of exhaust gases, which permits the engine to ingest more air/fuel. Although there is a cross-over pipe connecting the pipes from the two manifolds, there's the possibility that three of the cylinders connected in line to the gutted silencer might flow more freely than the cylinders connected to the OEM silencer, which might cause fuelling problems.

My sentiment exactly. I would never put a system out of balance.
Swap neither box or both..

So the X pipe is not connected in the middle. If it is surely the pressure is equalised.

 

[exdos]

So the X pipe is not connected in the middle. If it is surely the pressure is equalised.

If there are two different rates of flow into a merging stream then this may affect the pressure upstream within one or both of the streams: think of those venturi suction systems used in laboratories. If so, this could make fuelling of the engine less than perfect, because three of the cylinders connected on one manifold might flow slightly differently to the other three, whilst the ECU is attempting to fuel all the cylinders equally.

I was the person who started the gutted silencer mod for the Z4M, and I've been doing it for years now with the S54 engine, and I doubt that you'll find fitting just one gutted silencer half as quiet as fitting two. Personally, I gut them for performance and not noise.

 

[srhutch]

So the X pipe is not connected in the middle. If it is surely the pressure is equalised.

If there are two different rates of flow into a merging stream then this may affect the pressure upstream within one or both of the streams: think of those venturi suction systems used in laboratories. If so, this could make fuelling of the engine less than perfect, because three of the cylinders connected on one manifold might flow slightly differently to the other three, whilst the ECU is attempting to fuel all the cylinders equally.

I was the person who started the gutted silencer mod for the Z4M, and I've been doing it for years now with the S54 engine, and I doubt that you'll find fitting just one gutted silencer half as quiet as fitting two. Personally, I gut them for performance and not noise.

I think most have gutted for noise though. I doubt I'd see any benefit in performance unless it was night and day.

Will swap the other one over next weekend and see what difference it makes.

 

[goon]

Polished silencers......uurrgghhh how horrid, they shouldn't be visible, polished tailpipes yes but turkey trays a big fat NO.