Garages that could upgrade the diff
Discussion
Hi there,
I am looking at old upgrade threads and thinking about upgrading my VZ cv8 to a 3.9:1 diff ratio. It looks like this was something that monkfish would do back in the day. Does anyone know of any garages that are still around that would be able to do this work?
I was originally thinking about headers and cats (car already came with upgraded cat back and cold air intake), but from reading old threads, it sounds like diff would give the most bang for buck in terms of acceleration.
Never really done performance upgrades on a car before so feel free to educate me on this stuff if you feel inclined to do so.
Thanks!
Alex
I am looking at old upgrade threads and thinking about upgrading my VZ cv8 to a 3.9:1 diff ratio. It looks like this was something that monkfish would do back in the day. Does anyone know of any garages that are still around that would be able to do this work?
I was originally thinking about headers and cats (car already came with upgraded cat back and cold air intake), but from reading old threads, it sounds like diff would give the most bang for buck in terms of acceleration.
Never really done performance upgrades on a car before so feel free to educate me on this stuff if you feel inclined to do so.
Thanks!
Alex
Funnily enough a new diff is my next planned upgrade. You didn’t mention whereabouts you are, but my CV8 (and my previous one) get looked after by AAS near Newcastle.
They know our cars inside out, certainly at the mechanical level, and will be doing my diff along with a short shifter next summer.
Further south there’s MWP near Chester and Walkinshaw further south still, both have good reps.
They know our cars inside out, certainly at the mechanical level, and will be doing my diff along with a short shifter next summer.
Further south there’s MWP near Chester and Walkinshaw further south still, both have good reps.
Ah nice one thanks. I'm in Gloucestershire so Newcastle is a bit of a trek. But I'd consider it if it's the best option. Their name always seems to come up with regards to headers and cats so I assumed they were just an exhaust specialist. Have you been given an idea of cost? I'm assuming that they do a rebuild at the same time and it probably all adds up quite a bit?
Out of interest, what mods have you done so far? Any you'd recommend ahead of the diff?
Cheers
Out of interest, what mods have you done so far? Any you'd recommend ahead of the diff?
Cheers
No idea of the cost yet, but I’m sure it won’t be cheap 
My early CV8 already had the Wortec Sport Pac by the looks of it, so a bigger MAF pipe, airbox mod and a catback with a tune. Oh, and AP big brakes. And Pedders standard height suspension, and all the bushings look to have been polybushed. I think that’s it….
Since I bought it in 2020, I’ve had headers and cats by AAS, and they’ve serviced it every summer.
If it’s too far to travel, I’m sure Walkinshaw or MWP can do this level of work, no problem
My early CV8 already had the Wortec Sport Pac by the looks of it, so a bigger MAF pipe, airbox mod and a catback with a tune. Oh, and AP big brakes. And Pedders standard height suspension, and all the bushings look to have been polybushed. I think that’s it….
Since I bought it in 2020, I’ve had headers and cats by AAS, and they’ve serviced it every summer.
If it’s too far to travel, I’m sure Walkinshaw or MWP can do this level of work, no problem
As above. AAS come thoroughly recommended. They've looked after my Monaro for the last 7 years. Basic service work, clutch and gearbox work, brakes, fluid hard lines, steering. I drive 130 miles each way to see them.
They'll be able to do your diff, assuming parts availability ok.
They might NOT be able to code the speedo cluster to account for the diff ratio change. This means your speedo will read incorrectly.
If they cannot, the others mentioned should be able to do that bit, or the whole lot.
Another company I've read good things about are LS Performance Parts.
https://lsperformanceparts.com
They'd be able to code the cluster for a diff ratio change I'm sure.
I'd be getting quotes from all, but my experience with AAS is excellent.
I'd be tempted to get a diff rework from them, along with headers and cats, and then have my cluster coding and a re-map done through LSPP via Luis Sola to get the best out of all the mods together. From what I've read, Luis Sola is supposed to be the best of the best when mapping LS engines.
After that, it get mad. Engine open time. Different cams, superchargers etc etc. Big money time.
Just accept these cars are never going to be super sonic without big big bucks. They are fast enough though.
When your average Tesla can muller just about anything on the road from the lights and a roll, time has moved on.
They'll be able to do your diff, assuming parts availability ok.
They might NOT be able to code the speedo cluster to account for the diff ratio change. This means your speedo will read incorrectly.
If they cannot, the others mentioned should be able to do that bit, or the whole lot.
Another company I've read good things about are LS Performance Parts.
https://lsperformanceparts.com
They'd be able to code the cluster for a diff ratio change I'm sure.
I'd be getting quotes from all, but my experience with AAS is excellent.
I'd be tempted to get a diff rework from them, along with headers and cats, and then have my cluster coding and a re-map done through LSPP via Luis Sola to get the best out of all the mods together. From what I've read, Luis Sola is supposed to be the best of the best when mapping LS engines.
After that, it get mad. Engine open time. Different cams, superchargers etc etc. Big money time.
Just accept these cars are never going to be super sonic without big big bucks. They are fast enough though.
When your average Tesla can muller just about anything on the road from the lights and a roll, time has moved on.
Another consideration.
Hows your current gearbox? Any signs of it being excessively worn?
I ask because the CV8 cars got a different set of ratios in the T56 box compared to the LS2 VXR.
The ratios in the LS2 VXR Monaro are shorter and will give much the same results as a diff ratio change, however the cluster would not need re-coding in this instance.
A second hand VXR box would be a straight swap and probably cost no more to do.
Hows your current gearbox? Any signs of it being excessively worn?
I ask because the CV8 cars got a different set of ratios in the T56 box compared to the LS2 VXR.
The ratios in the LS2 VXR Monaro are shorter and will give much the same results as a diff ratio change, however the cluster would not need re-coding in this instance.
A second hand VXR box would be a straight swap and probably cost no more to do.
V88Dicky said:
No idea of the cost yet, but I m sure it won t be cheap
My early CV8 already had the Wortec Sport Pac by the looks of it, so a bigger MAF pipe, airbox mod and a catback with a tune. Oh, and AP big brakes. And Pedders standard height suspension, and all the bushings look to have been polybushed. I think that s it .
Since I bought it in 2020, I ve had headers and cats by AAS, and they ve serviced it every summer.
If it s too far to travel, I m sure Walkinshaw or MWP can do this level of work, no problem
Thanks for all the info! How much were headers and cats from AAS? And are they long tube? I've seen some headers and cats on the MWP website for 1.5k. so probably looking at a couple of grand after fitting I supposeMy early CV8 already had the Wortec Sport Pac by the looks of it, so a bigger MAF pipe, airbox mod and a catback with a tune. Oh, and AP big brakes. And Pedders standard height suspension, and all the bushings look to have been polybushed. I think that s it .
Since I bought it in 2020, I ve had headers and cats by AAS, and they ve serviced it every summer.
If it s too far to travel, I m sure Walkinshaw or MWP can do this level of work, no problem
Lincsls1 said:
As above. AAS come thoroughly recommended. They've looked after my Monaro for the last 7 years. Basic service work, clutch and gearbox work, brakes, fluid hard lines, steering. I drive 130 miles each way to see them.
They'll be able to do your diff, assuming parts availability ok.
They might NOT be able to code the speedo cluster to account for the diff ratio change. This means your speedo will read incorrectly.
If they cannot, the others mentioned should be able to do that bit, or the whole lot.
Another company I've read good things about are LS Performance Parts.
https://lsperformanceparts.com
They'd be able to code the cluster for a diff ratio change I'm sure.
I'd be getting quotes from all, but my experience with AAS is excellent.
I'd be tempted to get a diff rework from them, along with headers and cats, and then have my cluster coding and a re-map done through LSPP via Luis Sola to get the best out of all the mods together. From what I've read, Luis Sola is supposed to be the best of the best when mapping LS engines.
After that, it get mad. Engine open time. Different cams, superchargers etc etc. Big money time.
Just accept these cars are never going to be super sonic without big big bucks. They are fast enough though.
When your average Tesla can muller just about anything on the road from the lights and a roll, time has moved on.
Thanks for the info. I honestly think I'd be very happy with diff change and heads/cats. Im not going to go down the charger route. Love the idea of it but it would cost almost what I paid for the car in the first place. And I think I just like the idea of having some of my own mods on the car and going through the process, rather than wanting insane speed.They'll be able to do your diff, assuming parts availability ok.
They might NOT be able to code the speedo cluster to account for the diff ratio change. This means your speedo will read incorrectly.
If they cannot, the others mentioned should be able to do that bit, or the whole lot.
Another company I've read good things about are LS Performance Parts.
https://lsperformanceparts.com
They'd be able to code the cluster for a diff ratio change I'm sure.
I'd be getting quotes from all, but my experience with AAS is excellent.
I'd be tempted to get a diff rework from them, along with headers and cats, and then have my cluster coding and a re-map done through LSPP via Luis Sola to get the best out of all the mods together. From what I've read, Luis Sola is supposed to be the best of the best when mapping LS engines.
After that, it get mad. Engine open time. Different cams, superchargers etc etc. Big money time.
Just accept these cars are never going to be super sonic without big big bucks. They are fast enough though.
When your average Tesla can muller just about anything on the road from the lights and a roll, time has moved on.
Weirdly my gauge cluster already reads too low. It will read about 20mph when I'm actually going 23/4 for example. No clue how that could have happened. I do have 19s on the car but with the low profile tyres they aren't any bigger than the 18s, I don't think. So I'm hoping that perhaps that might negate the need to get the cluster recalibrated if I change the diff ratio (which would normally make it read too high, I believe?)
Lincsls1 said:
Another consideration.
Hows your current gearbox? Any signs of it being excessively worn?
I ask because the CV8 cars got a different set of ratios in the T56 box compared to the LS2 VXR.
The ratios in the LS2 VXR Monaro are shorter and will give much the same results as a diff ratio change, however the cluster would not need re-coding in this instance.
A second hand VXR box would be a straight swap and probably cost no more to do.
That's good to know. My car is on about 75k and the gearbox feels ok, apart from not always going smoothly into second unless I pause for a moment between the gears. Although I've never driven another one so I'm not sure what they're supposed to feel likeHows your current gearbox? Any signs of it being excessively worn?
I ask because the CV8 cars got a different set of ratios in the T56 box compared to the LS2 VXR.
The ratios in the LS2 VXR Monaro are shorter and will give much the same results as a diff ratio change, however the cluster would not need re-coding in this instance.
A second hand VXR box would be a straight swap and probably cost no more to do.
SS55RO said:
Weirdly my gauge cluster already reads too low. It will read about 20mph when I'm actually going 23/4 for example. No clue how that could have happened. I do have 19s on the car but with the low profile tyres they aren't any bigger than the 18s, I don't think. So I'm hoping that perhaps that might negate the need to get the cluster recalibrated if I change the diff ratio (which would normally make it read too high, I believe?)
Hmmm.What sort of revs are you doing when say at 60 mph on the cluster in 6th gear? And what is the real speed?
We need another CV8 owner to compare with.
Just wondering if you've already got an upgraded diff?
The tyres on your 19's should be 245/35's for correct-ish calibration. That is what the VXRs run.
SS55RO said:
That's good to know. My car is on about 75k and the gearbox feels ok, apart from not always going smoothly into second unless I pause for a moment between the gears. Although I've never driven another one so I'm not sure what they're supposed to feel like
These gearboxes are agricultural in nature and are NOT to be rushed thru the gears. Definitely better when warm too.Manly is one way to describe them.
Rubbish is another
I get on with mine just fine
SS55RO said:
V88Dicky said:
No idea of the cost yet, but I m sure it won t be cheap
My early CV8 already had the Wortec Sport Pac by the looks of it, so a bigger MAF pipe, airbox mod and a catback with a tune. Oh, and AP big brakes. And Pedders standard height suspension, and all the bushings look to have been polybushed. I think that s it .
Since I bought it in 2020, I ve had headers and cats by AAS, and they ve serviced it every summer.
If it s too far to travel, I m sure Walkinshaw or MWP can do this level of work, no problem
Thanks for all the info! How much were headers and cats from AAS? And are they long tube? I've seen some headers and cats on the MWP website for 1.5k. so probably looking at a couple of grand after fitting I supposeMy early CV8 already had the Wortec Sport Pac by the looks of it, so a bigger MAF pipe, airbox mod and a catback with a tune. Oh, and AP big brakes. And Pedders standard height suspension, and all the bushings look to have been polybushed. I think that s it .
Since I bought it in 2020, I ve had headers and cats by AAS, and they ve serviced it every summer.
If it s too far to travel, I m sure Walkinshaw or MWP can do this level of work, no problem
As far as your speedo is concerned, you should be at 1650 rpm at an indicated 70mph if memory serves
Lincsls1 said:
SS55RO said:
Weirdly my gauge cluster already reads too low. It will read about 20mph when I'm actually going 23/4 for example. No clue how that could have happened. I do have 19s on the car but with the low profile tyres they aren't any bigger than the 18s, I don't think. So I'm hoping that perhaps that might negate the need to get the cluster recalibrated if I change the diff ratio (which would normally make it read too high, I believe?)
Hmmm.What sort of revs are you doing when say at 60 mph on the cluster in 6th gear? And what is the real speed?
We need another CV8 owner to compare with.
Just wondering if you've already got an upgraded diff?
The tyres on your 19's should be 245/35's for correct-ish calibration. That is what the VXRs run.
V88Dicky said:
SS55RO said:
V88Dicky said:
No idea of the cost yet, but I m sure it won t be cheap
My early CV8 already had the Wortec Sport Pac by the looks of it, so a bigger MAF pipe, airbox mod and a catback with a tune. Oh, and AP big brakes. And Pedders standard height suspension, and all the bushings look to have been polybushed. I think that s it .
Since I bought it in 2020, I ve had headers and cats by AAS, and they ve serviced it every summer.
If it s too far to travel, I m sure Walkinshaw or MWP can do this level of work, no problem
Thanks for all the info! How much were headers and cats from AAS? And are they long tube? I've seen some headers and cats on the MWP website for 1.5k. so probably looking at a couple of grand after fitting I supposeMy early CV8 already had the Wortec Sport Pac by the looks of it, so a bigger MAF pipe, airbox mod and a catback with a tune. Oh, and AP big brakes. And Pedders standard height suspension, and all the bushings look to have been polybushed. I think that s it .
Since I bought it in 2020, I ve had headers and cats by AAS, and they ve serviced it every summer.
If it s too far to travel, I m sure Walkinshaw or MWP can do this level of work, no problem
As far as your speedo is concerned, you should be at 1650 rpm at an indicated 70mph if memory serves
SS55RO said:
I think maybe somewhere around 1300 and 1400. I'd go and check but I've SORNED it for the winter now. But wouldn't an upgraded diff make it go the other way?
Trying to get my simple mind around it. Yes, an upgraded diff will mean higher revs for the same speed in any given gear.
But if the clock hasn't been updated, then the car will read faster than you're actually going by more of a margin.
E.G. your real speed might be 30, the indicated speed might be 38.
Anyway, shouldn't worry too much, its unlikely you've got an upgraded already if its not in the paperwork.
SS55RO said:
Hi there,
I am looking at old upgrade threads and thinking about upgrading my VZ cv8 to a 3.9:1 diff ratio. It looks like this was something that monkfish would do back in the day. Does anyone know of any garages that are still around that would be able to do this work?
I was originally thinking about headers and cats (car already came with upgraded cat back and cold air intake), but from reading old threads, it sounds like diff would give the most bang for buck in terms of acceleration.
Never really done performance upgrades on a car before so feel free to educate me on this stuff if you feel inclined to do so.
Thanks!
Alex
Hello Alex,I am looking at old upgrade threads and thinking about upgrading my VZ cv8 to a 3.9:1 diff ratio. It looks like this was something that monkfish would do back in the day. Does anyone know of any garages that are still around that would be able to do this work?
I was originally thinking about headers and cats (car already came with upgraded cat back and cold air intake), but from reading old threads, it sounds like diff would give the most bang for buck in terms of acceleration.
Never really done performance upgrades on a car before so feel free to educate me on this stuff if you feel inclined to do so.
Thanks!
Alex
As we have the same model Monaro if you click on my username you will find the various mods I ve made over the years to my car. Probably the only thing I wouldn t bother with would be the exhaust cutouts and a Trutrack LSD I had fitted. I now have a Wavetrac LSD which is a lot better.
I had my 3.90 diff fitted by Monkfish and you need to be aware some makes will have a distinct whine and might get on your nerves. I can t recall the make of diff that Monkfish fitted but if you contact Pedders Suspension in Milton Keynes and speak to Roger or Andy they will no doubt remember. Also at the time my speedometer was electronically updated by Roger to take into account the diff ratio change.
As has previously stated by those two reprobates above
AAS are really good. The exhaust manifolds they make are mid length headers which allow a bit more ground clearance as opposed to the full length jobs.
It s been said before but if you mod your Monaro it s an expensive slippery slope If you intend to keep your car long term then go for it, but it s not worth it for short term ownership.
I m pretty much sorted with my car as it is, however I might do a rocker arm trunion upgrade and possibly the valve springs in the future.
Before I forget Merry Christmas to all .hopefully V88Dicky and Lincsis1 will behave themselves
John
mfp4073 said:
Hello Alex,
As we have the same model Monaro if you click on my username you will find the various mods I ve made over the years to my car. Probably the only thing I wouldn t bother with would be the exhaust cutouts and a Trutrack LSD I had fitted. I now have a Wavetrac LSD which is a lot better.
I had my 3.90 diff fitted by Monkfish and you need to be aware some makes will have a distinct whine and might get on your nerves. I can t recall the make of diff that Monkfish fitted but if you contact Pedders Suspension in Milton Keynes and speak to Roger or Andy they will no doubt remember. Also at the time my speedometer was electronically updated by Roger to take into account the diff ratio change.
As has previously stated by those two reprobates above AAS are really good.
The exhaust manifolds they make are mid length headers which allow a bit more ground clearance as opposed to the full length jobs.
It s been said before but if you mod your Monaro it s an expensive slippery slope If you intend to keep your car long term then go for it, but it s not worth it for short term ownership.
I m pretty much sorted with my car as it is, however I might do a rocker arm trunion upgrade and possibly the valve springs in the future.
Before I forget Merry Christmas to all .hopefully V88Dicky and Lincsis1 will behave themselves
John
Thanks for the info. I'm pretty happy with my monaro so I don't mind spending a bit on it. The only thing that really might tempt me out of it would be a v8 ute. Either a Holden or a Falcon.As we have the same model Monaro if you click on my username you will find the various mods I ve made over the years to my car. Probably the only thing I wouldn t bother with would be the exhaust cutouts and a Trutrack LSD I had fitted. I now have a Wavetrac LSD which is a lot better.
I had my 3.90 diff fitted by Monkfish and you need to be aware some makes will have a distinct whine and might get on your nerves. I can t recall the make of diff that Monkfish fitted but if you contact Pedders Suspension in Milton Keynes and speak to Roger or Andy they will no doubt remember. Also at the time my speedometer was electronically updated by Roger to take into account the diff ratio change.
As has previously stated by those two reprobates above
AAS are really good. The exhaust manifolds they make are mid length headers which allow a bit more ground clearance as opposed to the full length jobs.
It s been said before but if you mod your Monaro it s an expensive slippery slope If you intend to keep your car long term then go for it, but it s not worth it for short term ownership.
I m pretty much sorted with my car as it is, however I might do a rocker arm trunion upgrade and possibly the valve springs in the future.
Before I forget Merry Christmas to all .hopefully V88Dicky and Lincsis1 will behave themselves
John
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