Thanks for the input I decided to go with the stock size 305s. Got Falken Azenis FK510 saved $500 vs the Michelin P4S; they have not been reviewed yet by Tirerack but there's good feedback on the internet.

Back on topic, I'm very excited about getting the VAP tune to improve responsiveness it just takes forever after mashing the accelerator to get the car moving, I may just piecemeal the enjoyment by getting the tune first an then pulley after a few months. I'm also a bit leery about the new rubber and I want to make sure it can cope with the added power.

 

Don't get too excited about the tune "curing" the lag/delay in throttle response.
Despite having the larger crank pulley and VAP tune mine still has the lag when I mash the go pedal, it seems like ages before the gearbox kicks down and the car takes off, but it's really about 2 seconds at most. Of course that 2 second delay is very annoying when you wanted instant max response.
BUT it all depends on how you have been driving in the last few minutes.
If you have been cruising for a while with small throttle inputs you will get the lag, but once you have been getting into the throttle a bit the lag reduces to very little, maybe .25 seconds. You learn to live with it and not expect instant response when giving it WOT after cruising along for a while.
From my reading it's caused by a combination of the PCM (Power Control Module AKA ECU) and the TCM (Transmission Control Module) which "talk" to each other, and you have to "teach" them via your throttle use to react more quickly.
That said, the lag is only when you trigger the kick down switch, and with the pulley and VAP tune I find the part throttle response to be a helluva lot sharper than the stock response was, and several owners have asked VAP to dial back that response a bit because they feel it is a bit too sharp and sudden.

 

No lag with the MT, either with or without the VAP gizmos. Appears the 8HP still has the age old AT drawback.

 

I have a lot of respect for you and OzXFR, you're both very helpful to all forum members.

On this point my opinion is different:: In full auto mode the transmission will downshift just by rapid significant throttle pedal increase, don't need to go past full throttle to kick down position.

Even ancient auto transmission like GM 4L80E fitted to 90s Jaguar had part throttle kickdown.
I would be very surprised if kick down took anywhere close to 2 secs.

If you really want immediate acceleration then downshift with paddle so you're in the correct gear / rpm before hitting the loud pedal will give the immediate response.

Finally at the risk of going against Unhinged love of manual transmission I remember being asked many years ago if I really thought I could change gear in a manual as fast as an automatic, it was doubtful if anyone could then, with modern auto not even close.
​I totally understand having a preference for manual it's just that most if not all the claimed advantages of manual transmission don't seem to stand up to scrutiny.

Case in point DCT auto in GT-R will change gear in less than 100ms (0.1 sec)

AT have convenience when driving in start stop urban conditions with flexibility and control equal to MT when required by using paddles

 

In my 2015 R I have never experienced downshift lag anywhere near as long as 2 seconds when in normal mode. And in dynamic mode it feels close to "instant".
However if you very slowely increase the throttle input, it might not downshift at all - as it should be.
But any fast increase in the throttle input at low rpm's will result in a rather quick downshift(s) in normal mode, and very quick downshift in dynamic mode (downshift executed before the throttle movement is finished).

 

Paul,
I can't disagree with anything you've said. My statement was based on nothing more than Oz's comment regarding shift delay. I, otherwise, have no personal experience with the 8HP other than a couple of test drives that convinced me that the AT was indeed quick and the best I have driven, but still lacked the driver engagement and driver autonomy that is present with the MT. No argument that the AT is far superior in any of the performance metrics.

 

Just tested my 2017 SVR with the following:
- VAP lower pulley
- VAP tune (appropriately titled "Beast")
- VAP 200 cell cats/resonated/ceramic coated downpipes
- VAP lowering springs
- MP4S tires

OMG. Immediate acceleration. Perfect shifts. Traction light between 1/2 gears and 2/3 gears. Worth every penny and every bruised knuckle (lower pulley install).
Haven't smiled this much since (deleted due to the family nature of the forum.)
Thanks Stuart and Chris.

 

I forgot to add: This is the first time I have heard the supercharger whine ….
Dyno next week.

 

How is the exhaust note with the resonated 200 cell cats? Is the note still raspy? It's also far too loud for me with the roof down.

 

SVR, downpipes (200 cell cats w/resonators, coated) :
I would say 1/2 of the rasp is gone and overall a little quieter now, but still roars in dynamic mode, with just as many crackles/pops.
Initial cold start is livable now, but still loud relative to most all suburban cars.

 

 

 

Don't contemplate it, just do it!
I also have a V6S and I also went with just the VAP tune (from 375 HP to around 410 HP) to start with.
Pretty good but still not enough, so the very day my warranty expired I had the crank pulley and tune done (so from 410 HP to around 450 HP).
Wow, what a difference!
You would think that the second jump of 40 HP would not feel much different than the first jump of 35 HP (and even less difference in relative percentage terms), but it feels a LOT different.
And it's not just about the max numbers, it's also very much about improved throttle response and drive-ability, the "pulley + tune" really swells out the "below the curve" torque.
Two added bonuses as well - it now revs out cleanly to 7,000 rpm pulling hard all the way when before it started to wilt at 6,000 rpm, and the supercharger whine has gone from barely there to "warning, 747 taking off" at WOT.
To repeat myself just do it, you won't regret it.

 

Thanks OzXFR! Actually, i have already bought the pulley wheel and pulley but I received it just weeks before the end of the driving season (Danmark has wet and very salty roads nov-mar, slippery and extremely corrosive). It's going on next spring and I am already looking forward to it. With the MS4S on I dont expect huge traction problems but I did find out last summer using my Draggy that tarmac can have very different friction properties, new tarmac being much grippier. On old tarmac I recored 4.8s for 0-100kmh with lots of wheelspin, on new tarmac I recorded 4.2s. Slightly faster than I had expected but I have the lightweight battery, rotors, and forged wheels and a couple of minor mods such as towing hook, engine cover delete (total 80kg weight reduction), so I guess the 80 kg accounts for 0.15 sec reduction and the tune for approx 0.4s reduction. Will measure with the pulley tune in April 2019.

 

 

Sorry to hear about the belt trouble. Make me a little anxious. Which type of belt do you have. The 1st gen with the flat outer side or the belt with grooves on both sides?

 

 

My belt is 2nd gen...fingers crossed it won't slip

 

 

Hi Everyone,

Just to clarify the belt situation. Our supplier (who is the OEM supplier to Jaguar) produced our order of belts in two batches. They sample 3 belts from each production run at random and record average length. The first batch had an average length which was 7mm longer than our specification. Some people reported slippage from this batch of belts.

The second production run much more on spec, nobody has reported slippage from production run number 2. To change the belt, nothing from the FEAD is required to be removed, just get a socket & bar on the tensioner, remove tension and slip the belt off/on.