Hi All,

I have a 2.1l 16v Zetec running weber 45's ( 3 hole progression ), standard cam's.

After having my car tuned last year and produced 184bhp / 165lb ft.

Took the car to be retuned on a RR and it now produces 151hp / 146lb ft, less the running the rich. The ignition map hasnt been changed.

On the way home, found the car to be popping between 1-3k rpm, a dog to be pulling off from standing start.

Trying to find out why the difference, I have found out the below today.

1.

F16 emulsion tube
145 air correctors
60 idle jet
115 main jets

2.

F16 Emulsion tube
190 air correctors
55 idle jet
115 main jets

3.

F16 Tube
185 air correctors
55 idle jet
115 main jet

4.

F16 tube
155 air corrector
60 idle jet
115 main jet

Now my question is, should these jets be all over the place like above or should they be the same ?

In theory yes but please be carful check the size of the jets not just the numbers I have seen lots of jets that have been drilled out not a good practice but it happens. The weber has a lot more jets than what you have listed check them all. I would want a 2.1 zetec making more than that power wise. No reson why you should have lost that amount of power unless something has changed a lot i:e exhust blocked air filter or timming

Forgot to say if it was mine I would be on the phone asking what the hell is going on

If they were tuning each cylinder then you could see differences, I have seen the forward carb jetted differently if the carbs stick out the side as it takes the initial buffet of air when moving.

Your jetting is all over the place so unless they have been drilling out It looks wrong to me.

Rolling road BHP means very little, coast down dynos are notoriously inaccurate, to get 184 bhp without cams from a zetec with carbs is very optimistic. I never bother dyno'ing my Westfield, it means nothing. if you had said 'my car used to do a 4.9 seconds 0-60 but now does a 5.5 second 0-60 that would be a better reflection of a problem.

[Edited on 2/6/14 by lordbenny]

I know what you mean, every RR will show different results due to setup, temperature and so on.

The difference in performance wise is like going from a subaru impreza sti into a 1L diesel pug 106. Okay thats abit drastic but you get the idea.

Driving it before you would feel a sense of enjoyment, power and the confidence of when driving the car you had the power when needed, you may as well now call me driving miss daisy.