Loss of power over time.

[badwool]

Looking through my old receipts from when i purchased my car and found the old RR results.

Car has been to the exact same place last month, using the exact same hub dynometer.

Only changes are the cat has been removed since.

What could cause a loss of power since the original RR? is their anything obvious?

I have heard mentioned that filters distances on the itb's can make a difference but surely not 10+hp?

[VTSLeics84]

Head gasket? Piston rings?

[badwool]

get it compression tested?

[Krys_23]

You've answered your own question.

[badwool]

is that a long winded way of saying yes?

[Quick]

Weather can make difference.

Calibration of the dynometer can drift over time.

Tyre pressure, wear, brand can also.

Whats the difference like? Hows the line of the graph?

[badwool]

Weather can make difference.

Calibration of the dynometer can drift over time.

Tyre pressure, wear, brand can also.

Whats the difference like? Hows the line of the graph?
Not a tyre issue as it was a hub dyno.

let me take some pics this evening and will post them up.

the graph with less power has a much smoother curve.

original was 160.1hp at 120mph

second

148(151 maybe) at 101mph

big difference eh?

[Quick]

Was it tested in the same gear both times? as the wheel speed is different!

[badwool]

Ooo not sure, think he did it in 4th this time though

[badwool]

http://i83.photobucket.com/albums/j295/deadlydime/2011-05-13230126.jpg

http://i83.photobucket.com/albums/j295/deadlydime/2011-05-13230202.jpg

[chinkostu]

Different gears there, cant get an extra 27mph out of 186rpm. Plus you cant get 120 in 4th either

[badwool]

Which gear do you think the bottom image was done in? Thing is pip, the guy who did the work is extremely reputable, wouldn't that be a huge error on his part?

[badwool]

Top image rather, bottom was in fourth. Isn't fourth closest to 1:1?

[chinkostu]

guessing rev limit is 7k? gotta be 4th due to the low speed

[badwool]

They were both in 4th.

[chinkostu]

If you can get 120mph in fourth you are a hero. Must be fifth

[DanGT]

Sounds like were both 4th, but your mention the ITB air filter? Has this been changed? if so I makes a huge difference, I had an ITB'd Clio and it made 221bhp at the fly with a panel style filter and 205bhp with the individual sock filters!! Back to back tested as well.

[badwool]

If you can get 120mph in fourth you are a hero. Must be fifth
why would that make me a hero?

im just telling the facts.

either way, any helpful suggestions other than that?

re the filters, same filters afaik.

like i say the only thing i can say ive done is taken off the cat

[chinkostu]

why would that make me a hero?

im just telling the facts.

either way, any helpful suggestions other than that?

re the filters, same filters afaik.

like i say the only thing i can say ive done is taken off the cat

Because 4th isnt long enough!!

look at the speeds and rpm on both graphs. one shows 120ish at 7k, the other shows 93ish at 6800k.

edit: also, look at the ratios. i don't see why you're still contesting!!

[badwool]

Because as mentioned, I have checked, they were both done in fourth, that is a fact do ends that line of thought.

Side from that 5th would show a lower bp anyway.

What we have come up with is perhaps a different gearbox.