4.0 ECU in a 3.6

[cookie450]

Does anyone know if it is possible to run a 3.6 with a 4.0 ECU and chip. If feasible what effect would that have on the performance characteristics.
I have a 52 plate tuscan with a 3.6 engine - block number and original registration documents all tally and indicate this to be the case.
My ECU has been labelled 4.0 ECU. Haven't looked at the chip yet but interested to know if others have experienced ?
thanks
steve

[nrick]

There are 2 ecu types, a single connector and a triple connector. As far as I know you can use the same ecu, the chip inside is the important factor and each engine needs the right data chip (3.6,4.0, decat) this allows the engine to run close to the optimum map but some manipulation is available from the adaptives and the closed loop control. My guess is the adaptives would accomodate the difference but couldn't guarantee it. Would be interested to see the adaptives.

Not uncommon for the 3.6's to actually be 4.0 either because of a shortage of parts at the factory, or multiple rebuilds that might have occurred.

[Cooper Green]

i Have also heard that on occasion 3.6 litre cranks where used in 4.0 blocks due to shortage of stock, dont know how much this is true, but yet another reason that every TVR offers a different experience , even in the same model range. God Bless Em !

[Templedog]

My Tam was running a bit rough and rather rich. One of the things Jason at TVR Power checked was that the wrong chip had been installed, ie 4.0 rather than 3.6, apparently not unheard of. As it happens it had the correct chip but putting the wrong one in isn't a good idea as the map will be wrong for that particular engine.

[RedSpike66]

Cooper Green said:

i Have also heard that on occasion 3.6 litre cranks where used in 4.0 blocks due to shortage of stock, dont know how much this is true, but yet another reason that every TVR offers a different experience , even in the same model range. God Bless Em !

There was only ever one size block - different engine sizes arrived as a result of crank/conrod/piston changes. The 4.0L was first SP6, the 3.6 came later.

[nrick]

but there were some 4.0l fitted instead off 3.6 with 3.6 on the log book.

[Cooper Green]

The block may be standard across the range at the time , with the 3.6 coming later, but the length and throw of the con rods, and crank design is another way to increase swept volume iirc, not that piston size needs to increase to see an increase in displacement and capacity. I know of at least one 4.0 fitted with a 3.6 crank as an ' easy fix' as in stock without the owner realising.

[cookie450]

My block is stamped up as 3.6, my log book says 3.6, it's just my ECU that says 4.0 - in the ubiquitous black marker I will get a look at the actual chip next week when I'm back home and see what that has to say.
No running problems with it, 332bhp and 300 lbft though peaked low at 6400 rpm.
My 450 chim had a 5.0 ECU - again according to the phantom black marker pen !

[Cooper Green]

That sounds about right, my old griff 4.0 had the original embossed 'land rover ' stamped on the ECU casing. I had heard stories of stocks running out and staff land rovers in the car park being robbed of ECU's to get the cars out of the factory. This caused concern when i came across it but the car ran faultlessly for 2 years,and its what's inside that matters. Again more of the great TVR mysteries that keep these threads alive.