Shunting 5 ltr and RoverGauge

[blitzracing]

Im looking for someone who has a 5ltr that shunts and access to RoverGauge. I want to know the active load points in the fuel map where the shunting occurs. I have this for the 4 ltr engines- its the second row down between around 1400 to 2000 rpm, and by adding enough fuel to over ride the lambda cycling you can reduce the shunting significantly. It may be further down the map for the 5 ltr - as it draws more air so I want to check this. In exchange for this info' Ill blow a modified map into the blue tune, and supply a modified chip and switch-able tune resistor so it can be tested easily by switching to the blue map as a freeby. Anyone up for it?

[NZ fan]

I'm happy to supply the load cell data but living so far away I don't think testing the chip for you would be on the cards.
Just FYI mine is most noticeable @ around 1600 rpm in 3rd (about 40 kph) and 1400 rpm in 4th (around 50 kph) if a rovergauge screen shot would help just let me know. Cheers.

[blitzracing]

The shunting is where Id expect it RPM wise, I just need to load points if you could please?

[NZ fan]

No problem just might be a day or two till I can get it done. Might get the missus to drive while I watch the laptop. She,s pretty happy driving in that rpm range.

[mb450]

Hi Blitz
I know you're after a 500 but I've do have a 450 that shunts - got all the gear to blow a chip and rovergauge. Happy to swap out maps etc and generally mess about

[OleVix]

I have to say that I believe the throttle pot can lead to shunting, if its worn and gives spikes or holes in the voltage. I will know this for sure when I get the new pot!

[Chuffmeister]

I have a shunting 500 with RG, but no MOT at the moment. Is it something that can be done in the garage or something that needs to be done on a long run?

[blitzracing]

mb450 said:

Hi Blitz
I know you're after a 500 but I've do have a 450 that shunts - got all the gear to blow a chip and rovergauge. Happy to swap out maps etc and generally mess about

The idea at this stage is to simply modify the current TVR map to see if it can reduce the shunting- I have copies of all the base maps, so its simply a case of knowing the load point for your engine, so I can apply it to the specific map and test it, so yes please let me know the points and ill send you a new .bin file for the blue tune.

[NZ fan]

Having a bit of trouble with the windows laptop and rovergauge, keeps freezing then I have to close rovergauge and re-open it and switch usb ports before it will connect again. Anyway hope this is of some use I have ticked two cells where it is shunting. (Between 1400 and 1800 rpm)

[blitzracing]

That makes a lot of sense- its just one additional line down on the 4ltr chip. Ive modified a stock 5 ltr and 4.5 TVR catalyst map to override the lambda cycling between 1400 and 1750 rpm and put it in the blue tune, so the white is unaltered. To access the blue map you just need to unplug the tune resistor and replace it with a 1.8 k one, and then do an ECU reset (unplug and re-plug the ECU) to clear the fault code it will generate as the tunes are switched.

There a modified 4.5 map here:

https://www.dropbox.com/s/vjvwbzibavdc5pt/TVR%2045...

And a modified 5ltr here:

https://www.dropbox.com/s/hri37yckzsyofhz/TVR%2050...

The blue tune will fail an MOT fast idle test as the engine will be running too rich to keep the lambda probes cycling, plus the catalysts may run a bit hotter if the engine is held between 1400 and 2000 rpm for a long period- but seeing the abuse the TVR catalysts take when things go wrong, Ive never seen one cook yet, so I dont think one need worry about such. For MOT's it would just be a case of going back to white tune. Please feel free to download theses and try them out. Anyone who want to try a chip let me know and I can blow one.

[EddyP]

I'd be interested in trying this, 'i have the same problem on my 500.

Where abouts are you based?

[blitzracing]

Im near junction 14 on the M4. I dont mind dropping a chip and tune switch FOC into the post if you want to try it out and report back?

Edited by blitzracing on Wednesday 26th August 18:31

[OleVix]

I have some slight shunting at 900-1100 on very light or no throttle, and it feels mostly like drivetrain shunt. The CV joints I changed last year made the car very nice then, now they are full of slack, worse than ever... after one year the rest is in the diff I suppose

[mb450]

Great stuff - sorry I didn't reply earlier I'll give the 450 map a try over the bank holiday weekend.

[blitzracing]

Dont forget its its blue tune that modified- the white is unmodified.

[blitzracing]

mb450 said:

Great stuff - sorry I didn't reply earlier I'll give the 450 map a try over the bank holiday weekend.

Any updates on the test?

[mb450]

Hey Blitz

Yes sorry I did give it a go - no issues until I realised my airflow meter has packed put. (Seperate thread!)

Everything was fine - but things went a bit weird a couple of days ago. Initially thought I had an air leak but on poking about the maf is definately shot.
Overshoots to around 1v then takes forever to settle.

Once I've got a new maf I'll be back on it

[BarnFind]

Happy for you to use my 5litre

[blitzracing]

Ive got a car turning up at the weekend to do some testing. There may be some other parameters that are changed in blue tune other than the basic map, so I may need to revert to modifying the white map- but well see on that. I made a boob on the switch connections- I put female connectors on the switch I sent out by mistake, so it will need to be modified.