god damn shunt is killing me

god damn shunt is killing me

Author
Discussion

PapaButch

Original Poster:

235 posts

122 months

Saturday 6th January 2018
quotequote all
Hey guys been a long time since I've been on here - Hello!

The chimaera 4.3 has had a lot of work on it and is now back in action!

But before it goes, it is shunting so bad frown low speeds 10-50mph are just killing, constantly having to depress clutch as the backlash on the diff is going to kill it again after it has just been done!

car is tuned, remap, trumpets, decat straight through exhaust, smooth bore, injectors, camshaft etc

but can i do anything with the timing by twisting the distributor to help it at all? if i can, which way do i turn it biggrin?

Regards

Chris!

mike-v2tmf

772 posts

78 months

Saturday 6th January 2018
quotequote all
Moving your distributor will undo the good work of your mapper , assuming its been mapped correctly

TV8

3,118 posts

174 months

Saturday 6th January 2018
quotequote all
are you still using plug extenders?

Dr Mike Oxgreen

4,101 posts

164 months

Saturday 6th January 2018
quotequote all
TV8 said:
are you still using plug extenders?
If so, get rid of them!

Mine wasn’t shunting as such, but getting rid of the plug extenders made the throttle response distinctly smoother, less snatchy.

Try removing them and wrap the ends of the HT leads with tinfoil to protect them temporarily while you do a test drive. See if you get any improvement.

I did find that the heat socks I used were insufficient protection though, and after a year the ends of the HT leads had burnt through and caused a misfire. I’ve now replaced them with leads that have angled ceramic ends.

PapaButch

Original Poster:

235 posts

122 months

Saturday 6th January 2018
quotequote all


I have these on at the moment.

PapaButch

Original Poster:

235 posts

122 months

Saturday 6th January 2018
quotequote all
Those cheap metal things were long gone. Car does have a lt77 gearbox and old style diff...but the backlash on the diff sometimes is to much for me to bear when it starts jumping around.

jojackson4

3,026 posts

136 months

Saturday 6th January 2018
quotequote all
Map or chip?

PapaButch

Original Poster:

235 posts

122 months

Saturday 6th January 2018
quotequote all
Same thing on the rv8 unit you need a new chip for the new map

blitzracing

6,387 posts

219 months

Saturday 6th January 2018
quotequote all
Who remapped it (assuming it still 14CUX ?) . If this has been done properly it should have picked up an major issues with the fuelling on the rolling road. Large amounts of shunting can mean the ECU is trying to sort the fuelling out with big corrections if something is wrong in the first place. Best bet on the 14CUX is to run it on the green tune as you can add more fuel at the shunting point.

spitfire4v8

3,990 posts

180 months

Saturday 6th January 2018
quotequote all
Sounds bad if as described. Take it back to whoever did the work. Its only fair to give them another chance at improving it.

jojackson4

3,026 posts

136 months

Saturday 6th January 2018
quotequote all
PapaButch said:
Same thing on the rv8 unit you need a new chip for the new map
You can buy a chip
Or you can remap there is a lot of difference

bobfather

11,171 posts

254 months

Sunday 7th January 2018
quotequote all
Shunting and plug extenders? Different issues, plug extenders cause miss fire, shunting is not miss fire it's a fuel air mixture problem. I agree that removing the extenders is a good thing to do but it's not going to solve shunting

PapaButch

Original Poster:

235 posts

122 months

Sunday 7th January 2018
quotequote all
I’ll find out who done it as I gave the car to Kent Tvr (Paul) to sort out lots of bits and he done a great job but he took it somewhere for remap

PapaButch

Original Poster:

235 posts

122 months

Sunday 7th January 2018
quotequote all

PapaButch

Original Poster:

235 posts

122 months

Sunday 7th January 2018
quotequote all
Have spoken to Paul and because I wanted max power he has tuned it as so. So when foot is down or cruising at 70 the car is absolutely fine it’s just getting to that point!

PapaButch

Original Poster:

235 posts

122 months

Sunday 7th January 2018
quotequote all
Have spoken to Paul and because I wanted max power he has tuned it as so. So when foot is down or cruising at 70 the car is absolutely fine it’s just getting to that point!

wuckfitracing

990 posts

142 months

Sunday 7th January 2018
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Something is clearly wrong, it shouldnt shunt that badly. Mine doesnt and its all 100% standard.

Sardonicus

18,928 posts

220 months

Sunday 7th January 2018
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Mapping for max performace at top end should not compromise cruise/low RPM behavoir unless advance total figure is some how too much advance at low RPM, stock dizzy compromise if so and total advance may need taking down a tad unless you want to start playing with duzzy advance plate , bob weights, springs etc

MPO

264 posts

111 months

Sunday 7th January 2018
quotequote all
Try taking off your vacuum advance pipe and temporarily block the metal pipe on the plenum.

Have a drive and see if this reduces the shunting. If so, this could indicate a vacuum advance problem…

MPO

PapaButch

Original Poster:

235 posts

122 months

Sunday 7th January 2018
quotequote all
But the car dies when that rubber hose is taken off that spaceship looking saucer next to the dizzy