MPG 4 Sigma engine & oil pressure:

[S47]

Maybe it's our driving style, but our car is getting ~ 45MPG is this normal for a 125 Sigma??
My 2L zetec occasionally gets 35mpg on Motorway but 45 whilst giving the Sigma serious grief - WOW
Also the Sigma engine Oil Pressure Gauge is very erratic, anyone else have this problem, and how did you cure it??

[huwp]

I get closer to the high 30's in mine. Then again it gets thrashed most times it comes out and is carrying more weight as the SV model.

Oil pressure under load is usually constant at just over 4.

Temp always seems on the low side of normal until it starts getting serious abuse.

Caterham gauges....

Edited by huwp on Thursday 26th August 20:29

[S47]

HuwP
I'm just staggered by the MPG. I can't believe it I mean 1600 X flows are lucky to get low 20's
And the performance difference between the Xflow and Sigma is remarkable.
My OPG is wierd at start from cold its at 5bar+, then when warm normally 2.5-3 unless I really rev it when it goes up to 4bar+ Then occasionally when pootling along the gauge is showing between 1 + 3 bar, tickover is around 1bar.
I think the gauge is occasionally sticking, or maybe the sender has a problem. Whatever it is it's bloody irritatiing.

[Incorrigible]

The thing you're missing...

It's the pedal on the right

HTH

[Smollet]

I get around 35mpg on my Sigma 150 SV and I'm no lightweight so I think your return is probably quite accurate. The only idiosyncrasy I have with the oil gauge is on start up when it hits maximum then returns to zero before reading correctly. Worried the life out of me the first time I saw it happen as I thought something dire had happened.

[TheBoyBill]

The duratec cars do the same thing - But The tacho is in synchronous ZEROing with the oil so you can rest easy - Just make sure it POPS up to pressure before you go - Even though I know that.... the zeroing still make me every time....as you never know if it will pop back up.....Part of the charm of the 7


I suppose........

[EVS777]

Hi Mal, You bought that Sigma off Racing Dave then?? Are you going club meet Thursday??

Al..

[ArosaMike]

Should be about 4bar under load and around 2bar at idle when the oils hot. As for fuel consumption.....I honestly couldn't say.....I can get 50mins flat out round Snetterton on 1 tank though....

[S47]

Update
Just done 163 miles full to full, car needed 13.7 litres to fillup
Working it out 163/13.7=11.89 miles/litre, or in good old plain Welsh 54MPG
Anyone know how much the petrol the tank holds, coz the gauge was almost on MT when I filled up with only 13.7 ltres

[huwp]

Even with the bigger tank on my SV I never "risk" doing more than 200 on a tank. Of all the gauges the fuel guage is the one I trust least. Therefore I always work on distance travelled. Like you even when empty I always struggle to get move that 15 litres in.

[Dave J]

36 L

[S47]

36L huh - Guess that means that I have a hidden 20litres or so, Guess that means I'm gonna have to 'bend' the float arm in the tank to read MT when it is MT not MT when theres 20litres left in the tank. Anyone know how easy it is to remove float and 'bend' it?? Or how easy it is to remove the complete tank??

[Beverlonian]

MPG looks about right for my Sigma 125SV. With all the higher powered cars about I thought others would have filled in the wiki, last time I looked I was the only one there.

The fuel gauge on might not be accurate but at least the car still runs when it hits the red which I was led to believe it would not.

6000 miles and rockin!
Andy

[S47]

Further update, now we're really giving teh car some welly, I managed to run out of fuel after265 miles, on fillup it needed 27.3 litres, so I guess that means the pickup pipe ain't at the bottom of the take since according to Dave J the tank holds 36 litres, meaning I still had almost 2 gallons [8.7litres] left in the tank when I 'RUN OUT'
Incidentally MPG is now around 40MPG which is still
Winter job is to bend the Fuel tank float to correct the fuel gauge readings and lengthen the fuel pickup pipe to allow the full tank capacity to be utilised.
Wonder how many other Cat7's are permanently carrying around fuel they cant get at in teh tank, I my case the unusable 2 gallons weighs ~ 8kg or so. in a car as light as a 7 this XS weight ain't good - ain't good at all

[ArosaMike]

The fuel pickup/pump is out of a Fiesta and it sits about an inch off the bottom of the tank! You need around 5-7L in there before it will pickup and probably no less than 10L to avoid surge! Amusingly for a track based car, it's also on the far right of the tank which means that on any normal clockwise circuit, all of your fuel disappears to the other side of the tank when going round most of the corners!

[mic]

Fuel pick up is on the lefthand side of the tank.

[ArosaMike]

Definitely on the rhs on mine and every other Academy car this year!

[mic]

Fuel pump and sender assembly is fitted in the top of the left side of the tank on all Caterhams apart from the R500 which uses the the K series type pump. Bag tanks are RHS pick up.Earlier cars were different.

[S47]

WELL WELL - Fuel pickup pipe an inch off the bottom of the tank Huh!! I ain't being negative here but I thought Caterhams were a class above other kitcars, leaving the pickup pipe off the bottom of the tank is CRAP IMO. something the average Locost or Robin Hood Kitcar builder would never do, & aLL for the cost of an inch of rubber petrol pipe
Does anyone know whether the tank has a swirl pot fitted??

[mic]

Swirl pot is part of the fuel pump assembly. There are tanks available on new er cars which are slightly shallower, this means the pick up sits on the bottom of the tank. If you look at the brackets the tank sits on the new cars have bolt on mounts so that both type of tanks can be fitted.