Sigma engine upgrades

[RogueVector]

I haven't even got the car on the road yet and am already itching to do more work on it. Sad or what.

 

Anyway, I have a Sigma 125 and am interested in if anyone has experience of the Minster Power 160 upgrade vs the Caterham own 150 one?

 

Also if there are any others around...

[TobyCoulson]

There were rumours a while back that Ratrace were going to do 200bhp version but I've heard nothing more about it. I've got a 150 and I wish I had waited for the 175 Duratec version to be available as I think the 1.6 Sigma is fairly limited development wise. Go with the Minster as they generally have a a good reputation and I don't think there's a lot of price difference between the two for an extra 10bhp if remember rightly. Mountune might be another option.

[sevenmad]

Seem to remember someone on BC had the Burton upgrade and were not particularly impressed, certainly didn't get to 160 bhp.

Shawspeed claim to get 150-160bhp with throttle bodies etc, and beyond 200bhp with ported cylinder head, oversize valves etc etc but at high cost. here

Pro-tune also quote high outputs here

Personally I would go for cc upgrade if you want to keep you current car, this would make it easier to sell through cc if you want to trade it in.

The other option is to simply trade up to a Duratec as this permits further upgrades if needed, and may be less expensive in the long run. 2.8K is a considerable sum for an extra 25bhp.

[Martin J]

Try it first & get a few thousand miles under your belt!

The 125 is a great little engine flexible, good torque, economical & sounds good (especially the pops & bangs on the overrun )

True it may not have the top end of some engines but I think it's well suited to the 5sp box & you wouldn't catch me throwing nearly £3K at it for a 25hp gain.

One day in the greater plan of things I would like to trade K800 RUM for a duratec 175 roadsport but at the moment I'm saving for other things & besides the family have forbidden me from ever selling it!

[Stephen Long]

Yes as Martin says, its a great engine and

 

 

 

 

if you keep the ZV3 tyres it will drive like you have 250 bhp anyway 😬

 

Longy

[Martin J]

if you keep the ZV3 tyres it will drive like you have 250 bhp anyway

True, but those tyres bit me!

Best upgrade I have done was replacing the standard avons with Yoko's

[Miltec]

Or you could change to the Avon CR322 and it'll feel like 500hp

 

VX 1600 Live Axle

T440LKK

 

Edited by - Miltec on 21 Nov 2010 17:24:41

[Stephen Long]

can you get those in 14 inches 🤔

 

Longy

[Rickmercs]

Now before I dive in let it be clear that I am new to this forum and still finding my way around, but it seems that the 2.0 litre Zetec is proving quite a popular engine too, and this item seems like a bargain if it really is new and shiny as stated.

 

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=260655150078&ssPageName=STRK:MEWAX:IT

 

PS. Not connected with the seller in any way.

Rick

 

 

[Martin J]

Longy, I have yoko AO21's, basicaly a wet track day tyre & yes they are available for 14inch wheels.

[sevenmad]

*confused*Hi Rickmercs, zetec is a good upgrade for a xflow, but the sigma and duratec have the exhaust manifold on the drivers side, the zetec on the passengers. If you go from sigma to zetec your left with a big hole in the side of the car!

[mawmaw]

Having raced a Sigma for the last 5 years I feel I am qualified to comment. My engines have always been set up by Steve and Steve so give proper numbers. I have always run Shawspeed engines. They have varied from twin 40's with rally cams producing 155bhp (as a back up engine) through cooking engines on a standard bottom end with valve cut outs producing 180bhp to my current 204bhp dry sumped, forged pistons, steel rods, one piece valve engine.

The main point is, yes it is a fantastic engine, but please dry sump it for reliability, use steel rods when you can and talk to Jon at Shawspeed there really is nothing he doesn't know about this engine. In many ways it is preferable to the duratec, it is lighter, smaller and better suited to such a small car, after all twinks and bdas were 1600 so stick with tradition just upgrade it!

 

mark

[Martin J]

Interesting Mark Just shows the sigma can be made to produce much more power & still be reliable.

[mawmaw]

Martin, the thing is to get decent performance out of this engine, and to be honest pretty much any modern engine you need to bolt on some direct to head Tb's and a programmable ecu. Once you have done that you can release the power that is waiting to be released. Ie you have the options of tending to upgrad-itis without throwing anything away. i am guessing the 150bhp engine is like the 125 with tb's and an ecu. Now looking at the Jenvey and omex websites it costs £1800 plus Vat for an ecu, a loom and a direct to head tb kit. A session with Steve to set this up would cost around £400 so once VAT etc you can see where the £3k goes. The advantage is that once you feel the need for more you can get the rods, pistons, head work cams etc and that initial investment has been money well spent as you only need a trip to the rolling road to get your other stuff to work as it should.

42mm throttle bodies are good for well over 200BHP so are never going to be a restriction with this engine, so go on, Christmas is coming you know it makes sense.

 

Mark

[Martin J]

Friend of mine, new member Steve has recently upgraded to 150 spec but not before clocking up a fair few miles so it has been interesting hearing his views. (He might even reply to this thread, you never know *wink*)

He liked the flexibilty of the 125 but there is no denying that the 150 has more power at the top end & the upgrade really has changed the character of the engine. I can no longer keep up with him when he gives it the beans! 😔

You are right in that it despenses with the standard ford induction & single throttle body & goes for throtle bodies,different cams, tougher valve springs, oil catch tank (mine vents into the throttle body) & a manual cam belt tensioner to stop the belt jumping at the higher rev limit. The ecu isn't changed just reprogrammed (up to map h now) to allow higher rev limit etc.

The engine sounds quite different now but he misses not having so many pops & bangs on the overrun Only a very slight increase in fuel consumption.

[Martin J]

so go on, Christmas is coming you know it makes sense

Problem is Mark with two teenage Daughters budget might be a bit stretched!

 

Martin