Fuel consumption...

[funkyelise]

Anyone noticed any major fuel consumption change after fitting induction kit, exhaust etc? On a fairly steady motorway run last night it just seemed to be burning a bit more of the Optimax than usual. I did expect there to be a slight drop in mpg (drawing more air therefore drawing more fuel) but it was quite noticeable. (dropped from a usual 40-ish mpg to approx 33!)

[pley]

The will have an effect as more air is going in and out I guess. The thing to weigh up is the cost vs the sound! I know which I'd go for everytime!!

My S1 used to get about 40mpg
S2 ~30 mpg
340r ?? Who cares, it goes like the clappers!! Ha

[robert.sch]

Dear funkyelise,
My car being fitted with Itg Sports cat+exhaust seems
to use more Optimax now, pobably due to the increase
of cold air especially now in winter time.
Roberto

[Gfun]

Any one have any actual data on optimax does it do anything but cost more?

OK I have read all the blurb and understand it should be better but ...

I sort of like to use it but feel its more window dressing. OK it cost £20 to fill or £21 and I think it feels a bit different....

But anyone tested if it makes a difference in reality?

[dragCorleone]

Dear G,
id like to know that aswell G.
Don Corleone

>> Edited by dragCorleone on Friday 16th January 19:06

[BCA]

Depends on the car I guess, but in both my Smart and my dad Cerbera its covered its own costs by increasing the fuel economy to compensate.

In the Cerbera it stops it "pinking" not sure it does much else. In the Smart however, its quite noticeably happier to rev! Also means 6th gear isnt so limp around 60 - pulls alot cleaner.

[bogie]

This question comes up a lot - the K series does not have a knock sensor and cannot adjust to higher RON fuel...so no benefit...but some people use it and swear blind they get better fuel economy !...up to you...to be honest the price difference isnt that much when youve only got an 8 gal tank so may as well give it a treat now and again

>> Edited by bogie on Saturday 17th January 10:42

[dragCorleone]

[bogie]

When I had my S2 upgraded to 160bhp by DVA I also had ITG/Sports cat/Exhaust etc too...didnt even notice any drop in fuel consumption then - was still able to get 40mpg on the motorway easy and 30mpg avg everywhere else except track....I think the perceived drop is possibly due to driving style...when it sounds that good you are tempted to nail it at every opportunity !

Now I avg 30mpg on the motorway and 20mpg rest of the time....

[malbon]

Got exhaust/filter/tb/cat pipe.

no difference whatsoever.

Motorways/B Road driving

no difference

Thrashing the arse of it/Half thrashing the arse off it

No difference

I have a VVC and using Optimax gives me an extra 20 miles on average though using other 98 RONS there seems to be no difference inc BP Thingymajig. But obviously costs more so in theory cost wise I havent saved but it cleans the engine.

Normal fuel fill ups cost around £23 and I get 225/230 miles before REFILL comes up

Optimax costs £26/£27 and I get 255 miles before refill

[Gfun]

Thanks Malbon - just the sort of thing I was looking for (sorry but I am too lazy to mesure the mpg)

Ill keep on giving it a treat when a pump is free.

[james24]

I've found over the winter the mpg is quite a bit lower than it was in the summer time! Is this really due to more cold air, etc?!

[Beefcake]

james24 said:

I've found over the winter the mpg is quite a bit lower than it was in the summer time! Is this really due to more cold air, etc?!

Probably just your not booting it as much as the roads are a lot more slippy :P

---
www.midlandslotus.co.uk

[funkyelise]

As a follow up...

Did nearly 500 miles over the weekend and consumption was back to what I expected! I'm beginning to wonder if I wasn't just using the loud pedal a bit more than usual to experience the new sound! Speaking of which, now the exhaust has 'bedded in' properly, the noise is even better!

Back to fuel though...when I brought the car, I was running it on Esso Superunleaded. Now on Optimax, the difference in terms of consumption is negligible...but it definately runs better. It had started to pink but the change to optimax cured it straight away. I now wouldn't use anything else.