Hi guys,
I dont believe this has ever been discussed here on the message board.
Many F Type sport car owners have tuned their car. VAP or VIEZU, whatever.
Now the car had additional horsepower from the software tune. Also, more power if one or two pulleys are swapped out. So there is 600 horsepower and up to approximately 650 horsepower with pulleys.

My question is, how does this impact the added torque to the transmission and added possible stress to the electronic differential.
Can the tranny and the differential safely handle 600 to 650 additional horsepower ?

Thank you for your feedback.

 

When I had my car down at Paramount Performance (Viezu), here in the UK, the guys there were adamant that the 700Nm 'limit' of the ZF box was a soft limit, and is capable of far higher numbers perfectly safely. It surprised me, not least because all the info out there tells you that 700 is it, but I guess there is the anecdotal evidence from thousands of upgraded cars - through VAP, Viezu etc etc - that the box is indeed capable of bigger numbers than we have been lead to believe.

I am guessing that the same is true of the differential, or we'd be reading multiple horror stories both here and in the UK about failed diffs after tuning.


EDIT: I should add, the only reason I went with them is because I wasn't prepared to pay £1100 to take my car to the VAP authorised tuner here in the UK AND have to leave it with them for 2 days - I was told I would have to pay £200 MORE if I wanted to do the remap myself! I wanted to go with the VAP map, but the cost difference over here was too much. In another life I would have gone with VAP.

 

I know Stuart at VAP has discussed the transmission aspect of this in one of the many VAP threads.

 

They're gonna say it's fine either way, as they want your business. Just sayin'.

Any failures in other systems would be hard to link to their product. Pretty sure they know that.

 

I don’t think that’s fair. Last time we had this discussion (in 2021), it went down a rabbit hole. But I thought Stuart at VAP was upfront and handled it well.

https://www.jaguarforums.com/forum/f...tuning-244689/

 

Not really my areas of expertise, not a mech engineer, but I'm curious why there is any disagreement. Seems pretty obvious that more torque will stress the driveline more and increase wear, right? Not to mention that folks who tune probably drive the car harder as well. Higher average and higher max stress on everything. Am I missing something?

 

My rule of thumb is to have mechanical sympathy.

Avoid launching.
Wait for the car to be warmed up.
Etc.

I do enjoy the car, I just try to not abuse it "too" much.

 

When you launch enough times something eventually will give,with modified or non modified cars

 

Where are all the broken tranny and differentials?
I don't see them being reported?
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Not reported because we have the ZF-8 BULLET PROOF

 

Thanks and that was my point?
Yes of course more power from the engine will require the transmission and rear end to handle that.

This is a Jaguar forum where people come to post their problems. Do some searches and see what comes up?
Can you post any threads with broken transmissions and/or rear ends?

Yes we have threads about rear diff problems and threads about transmission problems. But none of those are related to power increases?

Another missing piece is how many are breaking axles? I have seen maybe two cars break axles from launching on this forum. On any US muscle car forum such as Mustang, Cadillac, Hellcat and other forums there are dozens of guys busting stuff daily because they are pushing WAY more power than even the most powerful Jaguar could ever hope to achieve! When you go up to 1500+ HP NOW you will be breaking things! That's not even the top with a twin turbo V-8 setup.
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How can you say with such certainty that some of the posted transmission and differential problems are not related to, or influenced by, increased power? I'm personally not ready to say they are not, but I guess I agree that it's not completely clear that there is a huge problem going on either.

 

Well…I am struggling to think of ANY postings regarding transmission failure in the F-Type (the ZF 8 speed).

 

simple as if you bench press 135lbs as your Max then you try to bench press 315 something is going to give,granted we all understand that the standard ZF Transmission can take some abuse to 700hp plus if your not putting slicks on and going to track every week ,now the haft shafts will go before anything

 

simple as if you bench press 135lbs as your Max then you try to bench press 315 something is going to give. Granted we all understand that the standard ZF Transmission can take some abuse to 700hp plus HP
if your not putting slicks on and going to track every week. Now the haft shafts will go before anything ELSE DOES

 

Could you make a case that additional horsepower via tune (e.g., VAP) could accelerate our well-documented differential problems?

 

I would think you could, as the harder you drive the more stress there is…People don’t tune to drive like Grandma ;-o

You will never directly prove anything I suspect, and I would suspect those potential concerns could be offset by changing differential fluid more regularly.

I personally think we all should use our cars in a manner that brings us the most enjoyment…Whatever that happens to be for ya…If not, what’s the point of all this ;-0

 

Yep you could make that point about everything really and you wouldn't be wrong. Increased power output is going to increase stress on the engine, transmission, diffs, motor mounts, axles, you name it. It is the modding game. But from a design perspective, there usually is a threshold where failure of components accelerates exponentially. I don't see from personal experience or anecdotal evidence that happening on our cars. I also trust Stuart and his team. Plenty of VAP tuned cars out there (mine has both pulleys, cats, intake, tune, and a ton of pops and bangs) that have been running just like stock for quite a while. I also believe as others have mentioned, you could have a stock F-Type with someone who absolutely abuses and/or fails to maintain the car that will fail earlier than any modded F-Type. Maintenance, as you point out, is also a huge factor - when I mod a car I usually accelerate fluid changes a bit.

Cheers,
Brad

 

DMeister I think you hit what I consider the real answer and that is fluid changes and maintenance.

Probably the best advice I have got on this forum is fluid changes and especially the oil change interval. I use a 6K-8K mile interval after reading this forum. With all the engine failures I still believe the factory drain intervals were a mistake by Jaguar. But again I tend to be a long term owner and that does change how you look at things.
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Yeah, those crazy intervals didn’t do any favours for anyone. Jag wanted to look greener I guess, and appear to have a lower cost of maintenance or something…They know things will be good for the warranty period regardless, so there was no skin off their back. Pretty dumb for sure.