125 Sigma to 150 Premier Power

[Dobson_justin]

I am in the process of changing my car, and still have options open as to the spec I will go for.  However thinking about a class 2/3 car, there are a few 125bhp sigma cars around, particularly ex academy cars.  For sigma engines it seems that Premier Power are the experts here. I know Rob Jacobs has this upgrade, but not sure if anyone else has experience in this area that may help?

I still have a Few options on the radar, but a sorted 150bhp sigma class 3 car sounds quite appealing.

Any advice welcome!

[K7 VCT]

Why not try out the better value option thst gives more improvements in the driving experience.

I changed my car to a ti-vct car then sevens and classics upgraded to 310s spec along with a lightweight flywheel.

Compared to the 125 and 135bhp car i started out with the car is now a different animal.

Excellent torque across the rev range along with a engine thats allways looking forward to the rev limiter.

It revs in a way my 1.4k supersport did after lots of extra pounds spent.

Overall i have a CATERHAM original car which means more of a return when selling on compaired to a non standard tuned engine.

Anymore info needed just ask.

BTW i spent less a third of the premier option.

I have a car thats 2 years younger than my 125bhp one too.

[Dobson_justin]

Ok, I am interested in alternatives also, but don’t quite follow your post - I am a simple chap and easily confused!

Ti-vct is a ford engine or something else? And what car did you start with? A 125 or 135? And finally, what was the cost of upgrading to 150?

Thanks! 

[K7 VCT]

The 125 is a 1.6 sigma fixed cam engine that gets you to 140 or 150 at a cost.

The ti-vct is the later version of said engine but has individually variable camshafts to increase torque and fuel economy across the rev range.

The ti-vct is 135bhp to start but with caterham factory 310 upgrade to 152-155bhp.

The cost for the 310 is less than the 140 on the fixed cam engine.

So i swapped my car from a 125bhp one to a 135bhp one and did the 155bhp 310 conversion to it.

[SKC]

Hi Justin,

You have several options open to you but first of all let me explain the engines.

Earlier Sigma powered Caterhams are powered by what we term as the "Fixed Cam" Sigma.  Still a great lightweight engine that revs well and is a great engine that can be tuned.  Performance levels from Caterham are 125bhp, 140bhp or 150bhp.

Later Sigma powered Caterhams are powered by the Ti-VCT Sigma (Twin independent Variable Cam Timing).  This engine features fully variable cam timing which is ECU controlled.  These cars from Caterham are either 135bhp or 152bhp versions.

The best upgrade you can put on any Sigma is one of our ultralight flywheel and clutches.  It doesn't give you any horse power but it does improve throttle response and the driving experience dramatically.  Just fitting one of the on a 125 Sigma makes it a nicer car to drive that a 140 Caterham upgrade.  Whilst there are those out there that comment on the Caterham light weight flywheel, this is not the same as our ultralight version, this is a further 2.5kgs lighter than the lightweight Caterham option.  

We do offer an F155 (155bhp) upgrade for the fixed cam Sigma which along with the ultralight flywheel and clutch should give you a competitive package for L7C Sprint championship.

Moving onto the Ti-VCT Sigma and potential upgrades.

The 310R is probably the best car I've driven from Caterham.  We have fitted an ultralight flywheel and clutch to one of these and it was a pleasure to drive.  Everything a Caterham should be, responsive and exciting.  This should give you 152bhp which as I understand it would fit in the "under 157bhp" class structure for the championship.  However, this engine is fitted with a single throttle body.  What we can offer is an upgrade on this with direct to head throttle bodies, our cams and engine management system.  As I mentioned earlier this engine features Ti-VCT which is ECU controlled and we fit a better engine management system that allows us to control the cams better, giving you further improvements in low and mid range torque which is more of what you'll be looking for in competition and general road driving. Whilst we have produced one of these engines to our F155 Ti-VCT spec, this is limited to 155bhp for the L7C sprint championship.  However the engine is capable of producing well over 160bhp if we allow it. Yes these upgrades aren't cheap but once you have the engine management system most of the parts carry over onto the next performance level should you wish to upgrade in the future.

We are planning to develop another upgrade for 310R customers to improve low down and mid range torque and more top end power.  I'm guessing this will be about 165 -170bhp.  We're looking for a car at the moment to do this on.

Can a "fixed cam" engine be converted to "Ti-VCT" engine? Yes but if your in the process of looking for a car, try and find the right car with the right engine in it to start with.

Regarding the comments about standard Caterham spec having higher re sale values, I think you need to decide do you want to win at racing....or drive a standard car.

If you want references from any of our customers please let me know and I can put you in touch or alternatively visit our workshop and sample a modified car for your self and discuss your options further.

Regards

SKC

 

[Dobson_justin]

K7 VCT, thank you for the explanation, that makes sense, and I really didn’t know that was an option, so that is massively helpful. 

[Dobson_justin]

Thanks also SKC for the huge amount of detail, plenty to consider also!  I will keep looking for an appropriate car, and then start making some plans.

[K7 VCT]

Hi Justin.

You may want to check out a orange 150 cdx car.

On pistonheads.

www.pistonheads.com/classifieds/used-cars/caterham/all-models/caterham-sigma-cdx150/7735949

Belongs to Jamie who moved to the USA i believe.

I sore the car at Penn 7 meeting and its very nicely prepared.

He had spent lots getting it to that stage.

Msybe what you are looking 4.

Its a very well sorted 150bhp car on a 2015 reg.

Best of luck

[Dobson_justin]

I have seen that, but as an ex drift academy car, it puts me off, as it sounds like it has been repeatedly thrashed. 

[K7 VCT]

Yes i get that too. But ask for information on it.

So much has been replaced and fettled.

Best running 150bhp engine ou will find as 150bhp engines were quite problematic so caterham stopped selling the option.

 

[The_ASH]

Interesting thread, thanks to all for raising the points and asking/answering the questions. 

[ChrisC]

Yes I know the 150 can be problematic, I have seen a few examples now and only one had balanced throttle bodies,  so poor understanding of how to setup the 150 doesn't helps it cause. 

BUT 

I suspect the 150 was dropped because CC could obtain the same power (and charge the same money)  with the 140 setup and retain the stock plenum, thus reducing the cost to them.   The 150 kit over states the actual headline hp produced, so in reality the 140 and 150 are much the same product, but the 150 sounds better.  

[SKC]

.......but the 150 should have more mid range torque than the 140 if correctly set up!!

As Mr Chapman used say..."horse power sells engines....torque wins races".

Regards

SKC*byebye*