Tune resistor for 14cux

[blaze_away]

I want to test how my chim runs on the "no cat" fuel map which is a 470 ohm resistor (green). Currently its on the (white) 3900 ohm resistor "uk cat" map.

Anyone got or details where to get, either a "green" resistor that I can do a direct swap with or failing that a white one so I can swap the 3900 for a 470 ?

[ClassicChimaera]

I must have one lying about somewhere Frank.
I'm curious as to why you wish to try it though. Have you got a de cat pipe?

I'll dig about for it later or probably tomorrow as I'm working at the mo.
Alun

[ianwayne]

Using the old Rt = 1 / ( 1/R1 + 1/R2), if you put a 535 ohm resistor in parallel with 3900 you'll get a resistance of 470 ohms.

It would mean you could easily remove it again if it runs terrible.

I doubt a few ohms either way is that critical, there is probably a switching threshhold.

Edited by ianwayne on Tuesday 24th January 17:06

[blaze_away]

My theory is that as my exhaust is custom made no cats but with lambdas then it raises question what does it run like on the 'no cat' map. Just curiousity really.

Ian, Good point about the parallel resistor hook up.....amazing how physics experiments eventually have a practical use albeit 45 years on !!!!

Alun, if youve got one O can borrow that would be fabulous.

[ClassicChimaera]

Yes no worries.
I'll let you know on here later on once I've dug through my pile of bits,,,, which includes an MBG HardTop,,, I sold the car 10 years ago

[blaze_away]

ClassicChimaera said:

Yes no worries.
I'll let you know on here later on once I've dug through my pile of bits,,,, which includes an MBG HardTop,,, I sold the car 10 years ago

Beer credits are waiting....

[blitzracing]

The only thing you will prove is how the car runs on an unmodified Range Rover map then- Although the ECU was remapped by TVR, its engine and map specific, so its very doubtful you will have a modified TVR non cat map in there.

[caduceus]

Is this something that fully decatted Chimaera owners should be worrying about? - (running a standard 14CUX on a decat setup) Or is this changing resistor thing just experimental? (forgive me but I know bugger all about leccy stuff )

[andy43]

blitzracing said:

The only thing you will prove is how the car runs on an unmodified Range Rover map then- Although the ECU was remapped by TVR, its engine and map specific, so its very doubtful you will have a modified TVR non cat map in there.

I'd agree with that - the noncat map is probably std range Range Rover so the fuelling could be way off. Worth speaking to Joolz at kitsandclassics about a remap - a safer option than risking underfuelling?

[blitzracing]

You can run just fine on the catalyst map with or without catalysts, and you wont gain any power by going "green" (non cat) as both maps run open loop at full power anyway. The only possible reason to want to run the green non cat map would be to help eliminate shunting (if its a problem) as you can richen the mixture a bit, or you can add pops and bangs to the over run. There are some hybrid maps around now on Steve Sprint web sites you can download FOC that just need blowing into an Eprom if you want to experiment, or as said Joolz will do a bespoke map for a very reasonable price.

maps here: Look at tune R3652

http://home2.btconnect.com/stevesprint/remap-14cux...

Edited by blitzracing on Wednesday 25th January 11:35

[QBee]

^^^^^^^^^^^^Wot 'e says.
I took out the precats, Mat Smith installed the Clive Y decatted Y piece and I handed Mat the multi tune resistor thingy that Clive sends with the Y, to install.
He read what it did and popped it in the bin - mine has the lambdas still in place, so as Mark says, it runs on the same map, catted or not. And I had less problem with shunting without the cats in, though it was never really a problem on my car.

[ClassicChimaera]

Here's the green resistor anyway.