Talk Morgan Forums Morgan Sports Cars Classic Morgans (pre-CX) Nice 4/4 here !

Indeed Mr B......I had TBs on my 4/4 together with Librands full sports exhaust system. It gave 156 bhp.. I don’t have the printout anymore otherwise I’d mention the increase in torque ....... or may be not 😉

It certainly sounded very nice.

I once drove a Caterham 7 fitted with a similar engine. IMHO The Sigma engine with TBs really suited that car.

The Omex based TB conversion could be a very interesting option for my Sigma, if you would say that the high rev power will increase without loosing at least the now existing low rev torque.

Heinz the torque is increased by 20 to 30 through the range. Things start to happen at 2500 revs at 3500 it takes off at 4500 wow!

Garethseries1, I can not find a conversion kit for the Sigma engine on their page. Are you talking about the Omex solution concerning the 4/4 Sigma 1.6 VCT TI?

If it exists, do they use Jenvey TBs for this product or their own developed TB upgrades?

Another question, have you compared the TB performance with a standard 4/4 or with one where the ECU was remapped?

Hi Heinz,
My car is a 2014 Sigma 4/4 it has Jenvey TBs and Omex ecu. The manifold and exhaust are Librands and that is the only upgrades it has. I had the set up done by Techniques.
The car was standard before the upgrade and nothing was happening under 3500 revs so in normal driving I had to use the gearbox more than I wanted to. Now in traffic I can use 5th gear. When I ordered the car I went for the Plus 4 body as I like the look but the wider tyres were no fun on corners so another reason for more power and torque.

Tried to PM you but it came up with some thing about a limit?

Hi Garethseries1, thanks for info, I have deleted some old mails and now PM should work again.

Heinz

I used the Aero set up end to end - yes you can buy the individual parts but I decided that if it all came from the same place- they were responsible for it all working.

Ultimately it ended up at Omex who finished the job off. I did once post the before /after graphs but they went with photobucket and when I sold the car.

Don’t buy throttle bodies with a torque increase as your primary ask. Buy throttle bodies to enjoy more top end power, a fabulous sound and a bit of improvement in torque ( over 3500 revs)

Just remember that with an extra 50 bhp- things like Panhard rods, better tyres, shocks and maybe negative camber plates really help use the extra power.

If I bought another 4/4- I’d do it again.

It fundamentally changes the car

Is it fair to say that in the Uk Williams and Technique are the only dealers who carry out the full conversion?

I fitted the throttle bodies to the Plus 4 myself. Following the instructions from Omex it was not particularly difficult but it has to be said I am accustomed to mechanical work.

Omex provide a kit for the 1600 engine, that their new kit for the Plus 4, uses their own high quality direct to head throttle bodies and they have simplified the installation from when I did it.

I am currently using the ignition map that they deveped for this system and that, together with the new, larger, 300 cell cat has made a great difference to low and mid range torque.

Their brochure can be downloded here.

The kit comes with a starter calibration but it would need to be tuned to match the exhaust system used.