Talk Morgan Forums Morgan Sports Cars Classic Morgans (pre-CX) 4/4 Sigma Throttle Bodies?

Curious... how much experience of these on here?

I know Caterham uses the same Sigma engine and there are loads of guys/tuners with the TB kit... and circa 150+BHP to boot!

Cheers, Peter.

I believe Jays (who used to be on here last year) had the conversion done at Henry Williams place and he was pleased with the result. I'm pretty sure that's what he had done but it was a long time ago now and the memory bank is not what it used to be.
If I remember correctly he wished he had hung onto it instead of buying the Roadster which he didn't keep for long.

Probably worth a call to Henry or Lawrie for a chat. There is a thread on here by Lawrie (Chunky4/4Racer) all about the race preparation of Henry's racing 4/4 Sport which we all enjoyed viewing.

I had the first road Sport converted by Russell Paterson in 2010 at the same time as they were converting the green car in which Tom Daley won the Championship. I had the full Aero Racing conversion including TB's, Omex piggy-back ECU, exhaust, 4.1 diff., Panhard rod, CR6ZZ's etc.etc. It was invigorating for short distances but not a lot of fun for long distance touring and a trip from the west of Scotland to LMC 12 convinced me to return to a Roadster Sport. It was effective in hillclimbs and even in PCT's .



I just found some of my old times from Forrestburn hillclimb in various cars for comparison -

Aero Racing Sport (CR6ZZ's ) 57.23
1950 cc MGB (Yoko 048's) 58.60
Carrera 3.2 (Road Tyres) 58.14
Subaru BRZ (Road Tyres) 59.76
Subaru WRX 2.5 (Road Tyres) 57.17
996 (Road Tyres) 57.95

This is exactly the argument why I will resist a conversion to TB. As fantastic as the full racing package is that your great 4/4 had, my 4/4 also offers 150 HP with normal intake and a nice torque with smooth sound that lets me drive to Italy with pleasure.
I might not talk like that if I hadn't had a P4SS for two and a half years. It was great but not for everything, and it was annoying for long distances, at least to me.

That's very thought provoking Heinz. I cannot recall what you have done to your car to obtain such a healthy power figure? was that measured on a dyno? I have been pondering getting my 4/4 Sigma on a dyno/rolling road tester to see what the power figure would be following upgrades. I have a Wolf ecu re-map, 200 cell cat with aero racing manifold, cold air-scoop into standard air box with K and N panel filter, iridum plugs, upgraded leads and Millers triple ester racing engine oil. I had hoped it would be around 135 bhp but I see a similar equipped car at Allon Whites is being quoted at 127bhp which surprised me. My car feels very lively, far more so than when I first got it ( 115bhp factory figure) which is very satisfying and matters more than pure numbers. Still keen to know the bhp however - but until a dyno session I have no real way of knowing I guess.

I posted this graph before here. Ok I added 10 Hp in my dreams since I had seen the graph last time, sorry for this misinformation even if 140 HP is also a good figure. May be it helped that it is an individually made tuning at the rolling road and not just an of the shelf remap. On the other hand I must honestly say that she runs better now than at the time of measurement.

Thankyou. No worries - I think 140 in a super light Sigma 4/4 is superb and a brilliantly balanced package. The fact you have kept the 4/4, considering how many really good drivers cars you have or have had in your collection, confirms how good it now is. I will get mine dyno tested and let you know how it goes.

A thought regarding torque. If you compare the blue input curve with the red output curve after the remap you can see that the torque was artificially reduced. This was confirmed by my tuner. He only had to take out this reduction. Either one wanted to protect the half shafts of the front drive in Fiesta/Focus and CMax or it had reasons to reach Euro5. I would pay attention if you do a dyno test. So that the engine is really free.

Andymot

My previous Morgan was a 2014 sport sigma same as yours..I did everything you have on yours inc Cains ecu remap,Librands manifold and sports exhaust,KN air filter and achieved 138.6 bhp on rolling road up from original 115.

So other owners experiences seem to be about the same.

As you say in a light nimble car it was a proper drivers car and I loved it.

I also had adjustable shocks and brake reaction bars and panhard rod.

I fully intended to keep it forever but I was seduced by the +4 Supersports !!!!...and who wouldn't be ? !!!

What approx BHP do you think my Sigma Would be Kev?

* Cains ECU map
* Librands Sports exhaust (with standard manifold)
* Williams ITG induction kit

It’s pulls much better than before all the above was fitted.