MRC Magic

[mark758]

When I fix problems on cars, I always try and change 1 thing at a time so I know what's worked, there is nothing more frustrating then changing 2 or more items and not knowing which was the fix. I understand the impracticality of this and the work would prob cost a lot more if the car had be reassembled each time one job was done and tested.

I fixed my air intake flap a month ago and the 5000rpm was back and of course felt naturally quicker
I changed the plugs in my car 2 weeks ago and even on some 95 RON it felt ballsitic afterwards.

The combination of these 2 cheap jobs seemed to have a significant effect to my experienced seat of the pants but I need to get some new data to verify it.

most cars have faulty air flaps and many still are on original plugs up to 60k miles as well as clogged air filters as first change is at 40k or 4 years then I'd imagine a highly tuned engine like ours which requires high revs to produce the extra PS will suffer as a result. By how much I don't know but my new data soon should give a clue

Excellent points.
Similarly I found 99 octane, new filter and new plugs all had very positive effects on the 'butt dyno'

[P_G]

there was a boost problem on the first dyno run leaking hose and sticky vavle so i would say that this would have given the low figures but here is a dyno from star performance that show better figures this was done in the first year i had the car

They are excellent figures Brooner and within 3% of your cars rated output which for a dyno is about right. What mileage did your car have on it then?

Sticky valve I gather was sorted with the clean but leaking hose? Is that a vacuum hose you are referring to?

[Brooner]

The valve was the one way under the manifold the leaking hose wass attached to it not sure about what it's called as i'm a mechanical <beep> as to the milage on the car i would say about 10k

[rs4mikek]

I am going to have the valves cleaned and heads ported in November. The car has a full Milltek + 100cell cats, MRC freeflow airfilter, and MRC custom remap. So far 395 ps, and i feel i can get a bit more one it has been cleaned. Will post graphs of before and after here in November. I was a bit surprised to read that sparkplugs make a difference ? So it would make sense to have them done at the same time ? What do you guys think ?

[sonny]

I am going to have the valves cleaned and heads ported in November. The car has a full Milltek + 100cell cats, MRC freeflow airfilter, and MRC custom remap. So far 395 ps, and i feel i can get a bit more one it has been cleaned. Will post graphs of before and after here in November. I was a bit surprised to read that sparkplugs make a difference ? So it would make sense to have them done at the same time ? What do you guys think ?

Personally I cant see how spark plugs would increase performance, unless you have a problem with your current spark plugs. I had mine changed at 22k miles, and they look fine and car drove the same.

[PetrolDave]

Spark plugs are key to a good "burn" in the cylinder.

If the spark plugs are fouled, or eroded so the gap is incorrect, then the "burn" will either not happen at the right time and/or be as even as it should be - this amounts to the same as the timing being delayed.

And we all know how sensitive the RS4 engine is to timing changes... they can have a big effect on power output.