flat spot i nearly hit the windscreen

[MATT]

hi

i have a 1.8 hlx with powerflow full stainless system including maifold and sport cat and ram air induction kit. when i plant my foot on the accelerator the car has one hell of a flat spot at about 2000rpm i nearly hit the windscreen every time.
but after that it seems fine and is really good as soon as it hits 3500rpm the car goes quite well as i have been clocked at 137 mph with a speed gun not the police, it was one of my mates he borrowed it from work.
whats the best way to get rid of the flat spot or do all bravos have it.

 

[Tom]

Its a fact of life. With all your mods the engine will now be running lean. The ECU is not designed to run the engine as it now is so simply can't cope.

Options are:
1) Super/power/etc.. chip but this will not get anywhere near the best results.

2) Dastek unichip piggyback ECU. This has to be tuned to your car on a rolling road so you are looking at about £700.

3) put it back as it was.

 

[Anonymous]

Re: Re: flat spot i nearly hit the windscreen

Matt I have noticed two things for which I do not have an explanation, but you never know. It might help.
The cause for your flatspot is almost certain to be your airfilter.
Mine used to be located directly to the air inlet manifold (as shown) which caused a great flatspot.
I have now gone to the other extreme of relocating the airfilter to directly behind the front bumper mesh (near the fog lamp) and the flat spot has greatly improved. Why? I dont know. One thing is for sure. It sucks in much colder air and all round performance has noticeably improved.

By the way...flatspots in the lower rev range is natural on 16v's. Its the way they work. Most extreme is the VTEC 16v engine. You'll have to rev it hard to overcome the flatspot.

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Fiat Bravo....different day different sh!t.