Henry_b said:

K&N filters are rock catchers not filters, they flow very well at the expense of filtering as you'd imagine you can't really have one without the other.

Look inside your intake hoses mine had a nice coat of dust which magically disappeared after fitting a proper Bosch paper filter..
The Oil on K&N almost always finds it way on to the MAF too which causes no end of issues.
I didn't notice any drop in performance or MPG without it..

15mpg is about right if it is crawling around town or doing short journeys with steep hills etc

Mine will usually do 18 around town and the best was 26mpg on the M4 at 2600rpm which is around 70mph

done with a brim to brim, no trip comp nonsense, however mine is accurate to a few tenths so it can usually be trusted..

Click to expand...

Grrrrrr said:

Yep, F1 engines don't have to last that long!

Click to expand...

kermit_rr said:

Still not figured out where the exhaust is blowing.
At this rate I'm going to have to take the manifolds off just to have a look see!!
Tried restricting the tail pipes to increase the pressure but no joy

Click to expand...

Henry_b said:

manifold gaskets
The flange where the exhaust joins the manifold
Or the exhaust itself..

To be fair my Manifolds have a very slight blow, which is quite common, whipping off the manifolds is quite an easy job once the head shields are out of the way..

Click to expand...

kermit_rr said:

I don't have heat shields on and no perceptible blow at idle. I have looked everywhere for telltale soot but don't see any

Click to expand...

Henry_b said:

Cylinder head gasket is another possibility if it is blowing to the outside world.

Similarly it can also blow into the Valley, take the oil cap off and rev the engine, if it sounds like you have another exhaust then thats the issue

Click to expand...

kermit_rr said:

Hadn't thought about headgasket. If i had to place a bet, it does sound like it's coming from underneath so hopefully not that. I'm paranoid that touching the heads will encourage the dreaded cracked block fun, given cracks occur where the head bolts go

Click to expand...

Henry_b said:

A set of ARP studs negate any issues with thread pulling, you'd don't need to hang off a a scaff tube to get the last 90 degrees either

IIRC ARP studs are torqued to 65lb/ft and thanks to the finer thread you get a much greater degree of control, great pieces of kit.

Whenever I do a RV8 a set of studs go in..

Click to expand...

kermit_rr said:

It's such a noisy engine!!! Even at tickover

Click to expand...

kermit_rr said:

I don't have heat shields on and no perceptible blow at idle. I have looked everywhere for telltale soot but don't see any

Click to expand...

kermit_rr said:

I don't have heat shields on and no perceptible blow at idle. I have looked everywhere for telltale soot but don't see any

Click to expand...

Enthusiastman said:

Do you re-set your fuel/trip computer each time you fill up to clear the residual memory of the fuel computor?? also is that 15 mpg poodling around town or on a motorway at crusing speed say 65 ish??? Have you tried a K&N panel air filter in your air box as these do help a little or do you just drive it like you stole it hence only 15 mpg. LOL

Click to expand...

Gunnerhavesome said:

I always re set each time I fill up for the simple reason that the sender unit is busted and don't want to pay for what really is a small light to go out. Simples, I brim the tank and know I can go 200 miles average, it is a 4.6. So drive 180 miles and brim the tank again which usually takes about 80 ltrs and as it is 100 ltr tank know I am right. However I do keep a 20 ltr top up in the back for Justin.

Click to expand...