How much will decat wreck your mpg ?

5th October 2011, 12:01

I have recently replaced my manifold, so now it's decatted. My fuel gauge is broken so i can't tell how much fuel i have

.
How many miles should i be getting from £20 at about 132 a litre ?

5th October 2011, 12:12

Depends how you drive it

5th October 2011, 12:14

hardly ever goes over 3k tbh

5th October 2011, 12:32

I'd estimate 30-35mpg if its in good health, maybe a bit more

5th October 2011, 12:32

With a decat, it'll sound different (nice) and you'll drive so you can hear it.

So it will reduce your MPG.

No one can give you an exact figure.

5th October 2011, 12:35

Well i suppose so tbh it would be better if my fuel gauge worked :/ I will have to get it sorted then it should be fine!

5th October 2011, 12:50

I fill up when the fuel warning light comes on.
I drive a 2002 VTR.

Approx £52.
The garage i use is 134.9 a litre.

Before decatting i was doing approx 350 - 450 to a full tank depending how i drove.

I decated the other week and filled her up when the light came on, next time the light come on i had done 375 miles, and i had obviously tested how much difference the decat had made so i thought it would have sapped the fuel but stayed roughly the same tbh.

So your answer is you wont notice much/if any of a difference from decatting

5th October 2011, 12:55

Depends on your driving style

It wont make much difference in my opinion.

Maybe a few mpg less than you got before.

5th October 2011, 13:32

You shouldn't notice any difference in MPG imo.

5th October 2011, 13:35

Ok well thanks for the help

5th October 2011, 13:36

Did you put the right lamba sensor in the manifold? and sleeved the other one to read clean air?

I didn't and it's defiantly overfueling, so loss in MPG.

5th October 2011, 13:37

I had mine decatted for a while and didn't notice a difference on mpg so you should be good to go

5th October 2011, 14:09

my mpg improved with decat......

5th October 2011, 18:07

my mpg didnt change noticabley with a decat
no one can tell you mate, becuase we dont know how you drive, if you do town driving, motorways, back roads??

5th October 2011, 18:12

Mostly town driving. I followed the guide on here for the manifold fitting. I have put one in the manifold but one is just sitting in my engine bay. I have not sleeved it yet.

5th October 2011, 19:47

Quote:

Originally Posted by rick_VTR

I fill up when the fuel warning light comes on.
I drive a 2002 VTR.

Approx £52.
The garage i use is 134.9 a litre.

Before decatting i was doing approx 350 - 450 to a full tank depending how i drove.

I decated the other week and filled her up when the light came on, next time the light come on i had done 375 miles, and i had obviously tested how much difference the decat had made so i thought it would have sapped the fuel but stayed roughly the same tbh.

So your answer is you wont notice much/if any of a difference from decatting

thats really good mpg

i struggle to get 250 miles out of a tank with mine aroiund town

5th October 2011, 19:52

Quote:

Originally Posted by LSOfreak

thats really good mpg

i struggle to get 250 miles out of a tank with mine aroiund town

i dont really do much town driving tbh.

i travel approx 50 miles home on a friday night, bit of town driving maybe a trip off somewhere on the weekend with the mrs.

then drive 50 miles back to the barracks on a sunday.

the car doesnt move much in the week unless i go into town for a takeaway or pick up stuff for the sax in the evenings.

for an engine thats done 114k miles i think its doing bloody well haha.
but then i do look after it, service regular etc so.

5th October 2011, 20:57

No difference in MPG

6th October 2011, 10:12

Just got 90 mile's from 10 litres of fuel in my de-catted R.. Actually drove sensibly for a full 10 litres lol.