Improved 150 Sigma engine

[mathubbard]

...I'm sure it's been discussed a lot in the past, but after owning a Sigma 150 engined car for about 5 months. I've just had the throttle bodies balanced and the throttle position sensor adjusted..... and the difference is AMAZING. The car is a lot easier to drive at part throttle in low gears, and I think the power output is noticeably higher. The mapping remains unchanged with the original ECU.

I'd love to know why Caterham didn't make a better job of setting them up when newly built or do they move out of optimal setup easily?

 

[ChrisC]

Mine tends to move a bit over the year, but its easy to reset (providing you have the tools needed).   Mine is very easy to drive part or low throttle, it pull clean from little more than tickover, and has no vices at all while all balanced.  

I love the 150, and the nice is fantastic. 

 

[Moggie]

I'm still in the honeymoon period with my 150 but I haven't noticed any problems in low gears at part throttle. If it's something that tends to move out of balance I'd be interested in what the symptoms were in case I experience it. Was the effect quite noticeable?

What’s involved in re-balancing the throttle bodies and adjusting the throttle position sensor?

[SM25T]

They had a lot of trouble with the Sigma 150 set up. I don't recall if it was primarily a software issue. It got dropped from the range in the end I think.

[ChrisC]

I think it was dropped due to cost, after all the 140 and the 150 make about the same power, they use the same cams (I am told) but the 150 had the expense of the throttle bodies, and they sell if for the same price.  Ok the 140 has the flywheel, but I can't imagine that cost more than the TBs.

My 150, when first converted had a poor TPS setting, which mad is almost impossible to drive slowly around town.  It ran like a car with a very aggressive cam, ie not clean until a given amount of revs, then it was fine. TPS set as per spec and the cars a dream.