I put alot of my mods on the car almost at the same time. When I just had the full s/s system with a decat and ecotek on the car used to do 113 no probs in 4th then pull in 5th.
Now, however, after fitting 17s, a bmc-cda induction kit and fse boost valve, the car only does 105 tops.
Could it be that my car is needing a service or do you think the ECU needs to be set up for the new changes on a rolling road?
Any input would be appreciated. The cars a 1.5 .


Thanks,
Sean

Hey Sean.

Dependant on when she was last serviced, that's your first port of call would be a thorough service.

Bearing in mind my severe carbon build up problem at 'just' 62,000 miles there's another possible problem.

Rich

Didn't finish did I?!?!?

Bearing all the bits in mind, it could be down to set up of the FSE valve and the air inlet adjuster on the inlet manifold.

I doubt your ECU needs setting, it should deal with that itself........

Rich

Ok thanks again Rich. You're a top guy

or it could be that if u made ur wheels a bit bigger ur cars slowed down a bit. stick ya old wheels back on for 10 mins and see if it goes faster again.

Arty

Wheel size makes a difference. I just changed my 195/50/15 tyres for 205/55/15's - on the last long trip I did, I checked with the mile stones and found a 7% change - i.e. my speedo used to be dead on at cruising speeds, now I find my trip meter says about 9.3 km for every 10 km I cover .....

Yeah but if the 'Copper' has used the correct size of 17" tyre - eg 205/40/17 - then the rolling diameter will be the same as original, and the speedo and that will stay the same......even though he's gone up from a 14" wheel.

If he's used such as a 215/45/17 - then you're spot on.

thecopper - if you've got a SMALLER outside diameter, your car car will go slower (but accelerate quicker). You might want to get a tape measure on a wheel and compare it with an old one.

Smotter, your new OD is about 30.5mm more than the old OD with an unloaded tyre. But I think you're now closer to the standard diameter - I think.

[b][color=red]Mark[/color][/b]

My model came out with 15"x7.5j alloys, and was originally shod with 205/50/15 tyres, so my current size will be a bit bigger than standard. However, this isn't a bad thing, 'cause I get a smoother ride and less risk of writing off my tyres on the many potholes, bricks, rocks, open manholes etc. which add character to South African roads.

The manholes are a serious problem these days; the unscrupulous masses tend to steal the covers at night to sell as scrap metal !!!

Well I managed to sort this problem!
My FSE was to 3.8 on the pressure gauge! Turned it down to 2.8. Then I re adjusted the ecotek valve and tweaked the air intake adjuster. Running like new now!
The wheels I have on are 215/40/17 what effect will this have on the speedo?

That's making your rolling diameter slightly bigger (40% of 215mm is more than 40% of 205mm), so your car will go marginally faster (top end), but will accelerate marginally slower.

Mark

Does that not depend on the width of your rim tho ? could be talking out of my a**e but I have 205/40/17 and my rolling diameter is smaller than my originals.

Should OK. The height of the side wall is equal to (for e.g.) 40% of the width of your tyre (205mm). But I guess if the rim width is narrower it may pull the rubber in and decrease the hieght, but not by much I wouldn't of thought.

Mark