Anyone Running a Green Tune Resistor?

[Chimpafrolic]

As the title suggests:

Is there anyone out there running a pre-cat 470 Ohms green tune resistor in a later car with cats?

I am interested in the effects on drivability and economy.

Thanks, Dave.

NB: I have a MA Tornado chip.

[Alexdaredevilz]

Im sure it turns the lambs signals off,

On mine I'm running green tune, no lambs and no cats, and a MA chip programmed for the green tune

My fuel economy is terrible at slower speeds, but once on the move easy 25mpg

Alex

[blitzracing]

Funny you should ask, Im running on that map (MA tornado) at the moment, and my lambda Gauge is telling me the fueling is spot on 95% of the time. There is a small rich spot at 2000 rpm under light load, but its no worse than the catalyst map so certainly I dont see an issue with it destroying catalysts. (Anyway all you need to check is they are not getting too hot, its pretty obvious when they do!) Dont know about the MPG at the moment, but its super smooth, not a shunt to be seen anywhere, and lovely idle. Dont forget you will need to tweak the CO trim on this map.

[haircutmike]

I run this, sans lambdas.

Perfect running apart from a slightly uneven idle, (probably nothing to do with it)!

[Alexdaredevilz]

haircutmike said:

I run this, sans lambdas.

Perfect running apart from a slightly uneven idle, (probably nothing to do with it)!

You following me?

[Chimpafrolic]

Thanks for the responses so far.

Its interesting to see there are people that have seen fit to do this simple resistor mod, I guess that means there must be some benefits right?

My car is already very smooth, the shunting seemed to vanish when I fitted the SC Power plenum spacer and my new Stealth cam has not really removed any of this low RPM flexibility.

Has anyone compared their economy with both the standard white 3900 Ohms resistor with the green 470 Ohms Pre-cat one?

At the weekend I did just over 300 miles on a full tank, I seem to get 25mpg from the MA chip and 27mpg from the original TVR 4.0HC chip!

So with an upcoming 3,000 mile round trip to the South of France planned its tempting to go back to the standard TVR chip.

The mythical 30mpg you often hear about still eludes me, perhaps because I do all my economy cruising at a steady 80mph, really not worth taking the TVR if I am going to cruise through France at a snail like 70mph.

I know its only a couple of MPG between the two chips but the TVR one does at least extend the touring range of the car by 25 miles or so.

Blitzracing has previously suggested that economy on cruise could be improved if I run the MA chip with a green 470 Ohms Pre-cat resistor.

Has anyone out there experienced such a benefit?

[Alexdaredevilz]

I'm sure you could get mark to map it for economy, but you will loose power, and you cant have both

Its down to you to decide what you want

[haircutmike]

Your profile reads accounts manager, no offence but maybe that's why you're chasing the mythical good mpg.

Personally, I can't be bothered, (I only get 8 mpg on T/D's) .

Edited by haircutmike on Monday 4th April 21:48

[SILICONE KID]

Why would you loose economy ? The AFR will be set slightly weaker on cruise ..The fuel map would be left alone higher up the rev range..Don`t know how the 14cux works but mine is tuned by map not rpm based..Think it something to do with the vacume..

[haircutmike]

Alexdaredevilz said:

You following me?

Stalking ............................

[Chimpafrolic]

haircutmike said:

Your profile reads accounts manager, no offence but maybe that's why you're chasing the mythical good mpg.

Personally, I can't be bothered, (I only get 8 mpg on T/D's) .

Edited by haircutmike on Monday 4th April 21:48

Thanks for taking the time to look at my profile Mike.

Just for the record I am an Account Manager not an Accountant.

Big difference.

8 mpg is a badge of honour for sure, that would make my trip to France £2.5k in fuel alone

I think the wife may make me go in my 48mpg Prius if that was the case

Still cant decide if I should call Mark Adams in to map it properly & fit the Omex 200 spark, or bite the bullet and MegaSquirt it?

Both options have their pros & cons but are a bit too wallet damaging right now.

With an expensive trip approaching I just wondered if a £0.50p resistor change would help a little?

If not the TVR chip goes back in for the trip.

[haircutmike]

Chimpafrolic said:

Thanks for taking the time to look at my profile Mike.

Just for the record I am an Account Manager not an Accountant.

Big difference.

8 mpg is a badge of honour for sure, that would make my trip to France £2.5k in fuel alone

I think the wife may make me go in my 48mpg Prius if that was the case

Still cant decide if I should call Mark Adams in to map it properly & fit the Omex 200 spark, or bite the bullet and MegaSquirt it?

Both options have their pros & cons but are a bit too wallet damaging right now.

With an expensive trip approaching I just wondered if a £0.50p resistor change would help a little?

If not the TVR chip goes back in for the trip.

Tounge in cheek my man!

I am actually envious of your trip!

[Chimpafrolic]

We're all good Mike, I love a bit of joshing

Why not be my co-pilot on the trip mate?

My wife prefers Easyjet anyway, she only has two phrases when I drive her in the TVR.

1) "Why didn't we come in the Prius, its so much quieter"

&

2) "SLOW DOWN"

[haircutmike]

O/T A friend of mine drives a Merc SL500 most years to the South of France and beyond, (he hates flying but loves driving).
He leaves a couple of days before then picks up his wife at their destination!

I'm even envious of him!

I'll be driving our old Transit motorhome to Berlin this summer as we are taking my 14 year old daughter and her friend, happy days .

[blitzracing]

You are really chasing the odd MPG here or there. The cat map runs leaner than ideal in low speed closed loop, but richer than ideal under light cruise, so how effecient it is depends on the what majority of your driving is. If you do run a leaner map, the engine will run hotter, and it can become a thin line between mpg and damaging the engine. Some of the origional Range Rover maps where know for that, and the increased heat used to damage the engine by causing the liners to move or crack, and thats way more expensive than the odd MPG! If you have a few pennies to spend buy yourself an Air fuel gauge and probe, then you can learn to drive it in the leaner part of the map, or more importantly check that its not running richer than need be at any other point.

[Chimpafrolic]

Quinny said:

I think the CAT map is the way to go....

When me and Ash went to Germany, we did 2000 odd miles, mile for mile, and at fill up time my MA chipped car consistently used less fuel than his...

Matching fill up for fill up, Ash would almost always get an extra litre or 2 in, more than me....

Nice to see you are still giving your sage advice to the poor folk Quinny, hows the AM?

I think all this is just another one of my posts like my "Is my Cam worn" one.

In that I mean I already know the answer.

With the cam I secretly knew the real answer was to let Rob fit a Stealth.

With this one however I have two choices.

1) MegaSquirt

2) Mark Adams

Got to stop spending money on this car

[Alexdaredevilz]

First step is to dyno it and check your air fuel ratio IMO

[blitzracing]

Dont forget the biggest gains are likely to be mapped ignition more than a fuel remap, after all a vac advance is pretty crude for getting the max out of the burn under light loads.

[Chimpafrolic]

blitzracing said:

Dont forget the biggest gains are likely to be mapped ignition more than a fuel remap, after all a vac advance is pretty crude for getting the max out of the burn under light loads.

I totally agree a proper mapped spark is where the biggest gains will be.

Has anyone tried the Omex 200 MA is offering me?

Even though I already have one of his chips it looks like a RR session plus the Omex 200 is going to come in at around the £800.00 mark.

From what I remember MA said he runs the load signal for the Omex 200 off the AFM which is kind of neat as the fuel & spark are driven by the same signal, and it all ends up looking 100% unmodified under the bonnet too.

Last year Shaun at V8D offered me a "Drive in Drive Out" Megasquirt fuel & spark installation for £1,200, more expensive but it does make future adjustments straightforward.

I can see a having the option to switch from a general "blasting around map" & a "cruise to the South of France economy map" as a great benefit.

So both options have their pros & cons.

Or should I just drive the damn thing and use the money on fuel?

Edited by Chimpafrolic on Tuesday 5th April 16:22

[Milky400]

Chimpafrolic said:

Or should I just drive the damn thing and use the money on fuel?

Do it