Guys,

Im trying to use my Brain to save money (On a Thursday Afternoon bored s**tless at work this is HARD!!). Im thinking........if I replace the punny little 13" Alloys on my Cinq Sporting with 15" Alloys fitted with 195/45 R15 Tyres........The Engine should pull less revs to get the same speed.......I work it out to be somewhere in the region of 10% less revs to do say 80MPH. I travel a lot of miles to work each day (Thats why I bought the car!!) so.....MPG is important!!!

Have any of you guys found your revs dropped and thus MPG increased by fitting bigger wheels/tyres on your cinq's????

I know I will loose out on acceleration but hey....cinq's hardly accelerate HARD anyway do they????

Let me know what you guys have seen by fitting bigger wheels?

Cheers

Andy

hmmm i was thinking about that the other day lol

great minds think alike

I dragged the 1108 turbo down to 26mpg on 15's, couldn't get that low on 13's.

Pete.

Links: 1242cc cinq, turbo cinq, Cinqs&Seis forum, Clubcento

26 MPG???? WOW!!! I cant understand it........the maths tell me that 15" wheels = bigger rolling radius therefore less revs for the same speed but less accelaration. Strange. Perhaps Cinq's defy the laws of physics eh???

lol

Andy

Originally posted by fixitagaintomorrow
I dragged the 1108 turbo down to 26mpg on 15's, couldn't get that low on 13's.

Pete.

Links: 1242cc cinq, turbo cinq, Cinqs&Seis forum, Clubcento

Click to expand...

A 6 speed box with shorter ratios would allow the car to pull bigger wheels with "ease". Therefore I would imagine that that would place less strain on the engine therefore saving fuel - whilst pulling the car at the same speeds? And also bigger wheels equals out the ratios on the 6 speed box - thus sorting out the top speed issue.
I'm crap at physics so that may be wrong of course!!
Matt

It's definatly not a custard now - 'cos I got a red one!!!
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Van Aaken High Boost Turbo engine for sale - "0-60 in the low 7's and enough top end to get you very seriously banned!!"

If anyone can provide me with the gear ratios for 5th on a std cinq and 6th on the 6 speed box, ill do the maths, based on std 13" alloys and 15" alloys too. Then we will know. I want to be able to pull 80MPH at 3500 or less!!!! I should then be able to get 48-50MPG out of my little baby!!!!

Cheers

Andy

Theory is an excellent thing, in practice wider tyres give a greater rolling resistance, escpecially if they are soft compound 'performance' tyres. If you could find a 125/82 x 13 and inflate it to 100psi then your fuel eceonomy would be superb. Wouldn't fancy a corner mind.

Cheers

D

Grumpy old git going fast downhill rather than downhill fast!!

Bigger wheels will make it harder for the car to accelerate, and the engine will have to do more work. More work => more fuel.

Originally posted by The Ugly Duckling
Bigger wheels will make it harder for the car to accelerate, and the engine will have to do more work. More work => more fuel.

Click to expand...

Hence - 6 speed box! Easy to accelerate - even with bigger wheels due to the ratios - less work - less fuel surely?? And bigger wheels = a decent top end?
Matt

It's definatly not a custard now - 'cos I got a red one!!!
------------------------
[email protected]
------------------------
Van Aaken High Boost Turbo engine for sale - "0-60 in the low 7's and enough top end to get you very seriously banned!!"

Originally posted by Rovrav27
26 MPG???? WOW!!! I cant understand it........the maths tell me that 15" wheels = bigger rolling radius therefore less revs for the same speed but less accelaration. Strange. Perhaps Cinq's defy the laws of physics eh???

lol

Andy

Originally posted by fixitagaintomorrow
I dragged the 1108 turbo down to 26mpg on 15's, couldn't get that low on 13's.

Pete.

Click to expand...

Click to expand...

weeeelll, that did include 2 70 mile stretches at an indicated 90mph. Add 10% for 15" wheels, take off whatever for speedo error, but it's slower to accelerate on 15's and doesn't seem to give as good mpg, even factoring in mileage and speedo errors. Might be to do with the fact it needs more boost to accelerate in 4th/5th though.

My silver 1242 with mods will give 50+ mpg if you keep it to an indicated 80mph.

Pete.

Links: 1242cc cinq, turbo cinq, Cinqs&Seis forum, Clubcento

Pete,

What wheels and tyres are you running the 1242 on to get 50MPG???

Cheers

Andy

175/50/13's. Car has induction kit, Supersprint back box and a superchip.

I reckon the superchip does wonders for mpg mind.

Pete.

Links: 1242cc cinq, turbo cinq, Cinqs&Seis forum, Clubcento

Tell me more about the Superchip matey?? What does it do BHP wise for the car and how much does it cost??? Where did you get yours fitted?

Cheers

Andy[8D]

Bought mine second hand, had it fitted at a Superchips dealer for just over £100.
They rolling roaded it before and after, quoted an extra 8bhp at the wheels. Feels genuinely quicker with no flat spot at 3k revs.

Superchips charge about £250 to buy/fit one, Think BBR do them too, maybe a little cheaper as well.

Pete.

Links: 1242cc cinq, turbo cinq, Cinqs&Seis forum, Clubcento