2.9 engine origins

[markbigears]

can anyone tell me what ford car the 2.9 came out of? and is it a standard unit or did tvr bump the bhp/torque up or any other mods. just curious to know the actual history, many thanks mark.

[johno]

The 2.9 was used in the Granada, and varieties of the engine were used in a lot of the Sierra range - XR4i, 4x4 etc etc

The original 2.8 lump was used in the Capri.

As I understand it TVR did not do anything with the management of the engine. By changing the air filter and exhaust they will have changed the performance and whether they di anything with the mapping is up for debate. From what I've been told though they didn't.

Cheers

Mark

[roulli]

how is the 12% boost in torque explained between the S3 and S3C?
Cats do normally have a negative influence on performance.

Patrick

[JSG]

S3c was set to provide more power low down and increased torque higher up the range - gen view is that this made it seem quicker.

This helped to compensate for the cats which were large to limit the power they took.

I had my S3c decatted which gave an increase in power at a slightly better exhaust note.

[markbigears]

how did TVR give the S3C more torque?
what mods were done?

[Greenv8s]

quote:
how is the 12% boost in torque explained between the S3 and S3C?
Cats do normally have a negative influence on performance.

Patrick

With the V8, they changed the cam to give more bottom-end torque, and sacrificed a lot of top-end torque. The torque curve is completely different and the rev limit is about 500 rpm lower. TVR claim identical peak power figures but in reality the cat version has a little more torque but 10-15 bhp less peak power. Not much to choose between them in actual performance though, mid range torque is more important than peak power.

Cheers,
Peter Humphries (and a green V8S)

[roulli]

quote:

I had my S3c decatted which gave an increase in power at a slightly better exhaust note.

and what do the lamda sonds tell the ecu? Does the fuel injection not go nuts?

[tvrmark]

It you restrict the exhaust flow(eg a cat)you will reduce BHP but increase torque. If you have a free flow exhaust you reduce torque and increase BHP.

mark

[tvrmark]

quote:

and what do the lamda sonds tell the ecu? Does the fuel injection not go nuts?

Hydrocarbons, the ecu will go in limp home mod.

Mark

[GreenV8S]

quote:

quote:

and what do the lamda sonds tell the ecu? Does the fuel injection not go nuts?

Hydrocarbons, the ecu will go in limp home mod.

Mark

Lambda sensors measure oxygen concentration. Taking the cats out doesn't make any difference to the sensors, but if you're planning to keep the ECU in closed loop mode you need to keep them plumbed into the exhaust i.e. you can't just disconnect them or leave them dangling in fresh air, this might be an issue if you're swapping the cat manifolds for pre-cat ones. But just knocking the cats out won't make any difference to the sensors. Insurance though, that's a different matter!

Cheers,
Peter Humphries (and a green V8S)

[JSG]

The cats were both knackered in in the S3c, TVR wanted over 800 quid for a new pair and my local specialist had some tubes made up for 20 quid each.

The manifolds and rest of exhaust system were left as before - lamda sensors still connected and he then retuned the engine to run with out cats. It was an excellent job and went a lot better (some of that maybe due to needing a tune anyway).

I told the ins co who said they had it listed as a S3 anyway and it wouldn't count as modified (I got it confirmed in writing) .