Just a word of caution... Swapping the two pulleys greatly reduces the contact area of the belt @ the supercharger pulley. This causes slippage... Compounding the issue, when this is done, would be installing a smaller supercharger pulley. Purely an engineering consideration, this is known as wrap angle.

 

Gotta love autocorrect,... Aggravating the issue, when this is done with a smaller supercharger pulley

 

With a conventional pulley, yes. With our Grip-Tec coated pulley, it's not an issue. We spent considerable time & money developing a datalogger that allowed us to accurately log PID's with enough latency to detect slippage, and to verify that is eliminated with our new pulley design.

 

Once again it confirms my post. My reply, if you read carefully, points out that swapping the idler pulleys reduces the wrap angle (resulting in slippage, undesirable harmonic vibrations, excessive belt wear). I also pointed out that adding a smaller supercharger pulley would make it worse. You replied that also swapping the supercharger pulley, thanks to the coating, it would minimize the slippage.
These are simple engineering concepts and at no point should anyone have to swap the idler pulleys. If that much of a wrap angle was REQUIRED when JLR engineered it, it becomes obvious that you would NOT reduce the wrap angle when you actually cause the supercharger to spin faster and add more passive power demand...

Lastly, the datalogger... This is again nonsense. You cannot detect belt slippage with it. To detect slippage you must have a sensor on the supercharger shaft (or pulley) or use a contactless sensor. Adding a sensor on the supercharger pulley is nearly impossible as it would create a serious balancing nightmare at 18,000 RPM. Slippage is detected when there is any deviation from the crankshaft angular speed X pulley ratio as it must remain directly proportional and linear at all engine speeds.

 

Nobody is disputing that the belt routing & tensioner is sub-optimal. Our pulley design can be fitted without belt slip because of the coating. Nobody reading this should be worried about slippage with our product.

100% you can detect belt slippage, if you think correctly and look at the correct data. We created a datalogger at great time & expenditure because there was nothing out there that allowed us to see enough PIDs, the correct PIDs, and a fast enough sample rate to accurately diagnose & tune. HP Tuners for example is pretty much worthless in this regard. If you are looking at the right data set and thinking like an engineer, you can 100% determine if the belt is slipping. Chris first noticed it by logging charged pressure and could see that under high load conditions, charged pressure would drop very slightly and then immediately recover, then drop very slightly and immediately recover. If you are only looking at charged pressure you would be uncertain if the drop was due to belt slip or other factors (like the bypass opening, which could be commanded by the ECU for a whole host of reasons.) Besides, the bypass opening would produce a much more severe pressure drop than what we observed. Fortunately, the Bypass Valve Angle is just one of the details our datalogger allows us to see, so Chris was able to rule out other possibilities. We designed a pulley with the coating built into it, and then tested on the exact same cars where the rapid pressure drop had been observed, and the problem was resolved.

So yes, our datalogger allows us to observe the right data sets to accurately detect and resolve belt slip. You just have to think like a CEO... whoops! I mean an engineer

 

I am going to give up on this because reasoning with somebody with ZERO engineering background is a waste of time. There is NO BUILT-IN sensor for the position/rotational speed of the supercharger shaft/axle. The valve angle etc is in no way related to belt slippage... i don't understand why you try and confuse the average person by deflecting to unrelated subjects. This is just like the TCU tune dropping the acceleration, custom air intake "power gains"... Every time you are called to task you change subject.

I am sorry if I am not the average car guy that believes everything they read, I did earn a degree in automotive engineering (in Europe's top automotive university) and have 30+ years of experience in racing and performance car engineering. I like facts and data, not smoke. I positively despise when someone suggests technical changes that adversely affect the durability, performance, and reliability of an otherwise well engineered product.

 

My 2 cents, @Stuart@VelocityAP and his team have always been willing to help me when I have questions. I'm always tinkering on my car and the datalogger has been very helpful in finding some anomalies I was unable to with a mid-tier Autel scan tool. When I did have a belt slippage issue after swapping my upper pulley, I noticed there was more some rubber residue around the parts near the snout, which I figured was most likely belt slippage. At the time though, that was not my main issue. I was having an issue with my boost bypass opening at 5K rpm in 4th gear and up. I reached out to my buddy in texas who had the same tuning company as me with the same mods.. Guess what, he noticed he had the same issue.. We both reached out to the tuning company and they told us "noone else has reported that issue" and basically said there's nothing they can do..... Fast forward a week or two and we both reached out to VAP to see if they had any reports of the same boost dump... @Stuart@VelocityAP was very helpful in that he pulled Chris in to the conversation. They hadn't had any reports of our issue as of yet, but he did say inform us that they were in the final stages of developing their software and that it MAY be helpful in diagnosing the issue. I'm pretty sure I was one of the first ones to buy it and within a week of getting the logs to Chris and a few test files my problem was fixed. After I sent him my last set of logs he mentioned to me that my charts looked like I may be experiencing belt slippage, which I already knew because of the rubber residue everywhere. So, I got a new belt that was a tad smaller and sent some more logs as well as kept an eye on the surrounding are.. No more small dips in the charge pressure and no more residue, so I would say that you dont NEED a built-in sensor when you can look at other data, the old adage "there's more than 1 way to skin a cat" comes to mind. Furthermore, Chris reached out to me last Spring asking if I had encountered a boost bypass opening in 2nd gear if I got close to redline as another customer of theirs had the same ECU revision and mods as me and was having the same issue since getting the TCU tune installed. I don't have the VAP TCU tune, but instead had the Viezu version, not sure the exact differences, but I digress. I confirmed I was seeing the bypass opening near redline in 2nd gear and it would remain open until i let off the throttle and reapplied throttle. Chris was able to reproduce on a test mule at their shop and when they rectified the issue with my ECU revision, sent me a new file and it's acting as I would expect. There was no smoke involved, Chris used the facts and data to fix my issue and VAP has always done so without talking down to me or making me feel stupid for asking a question. Ok.. so that was more than 2 cents..

 

Here we go again

 

"May be experiencing belt slippage" is a GUESS, without a speed sensor there is no positive data to quickly pinpoint accurately the issue. Products need to be rigorously tested on the road with a datalogger in order to be debugged correctly and only released when properly tested. The end-user is NOT the alpha or beta tester... Especially when then, there is "may be" involved...

 

no matter how you can measure something or not, everything works as it should for me now. Stage3 and TCU update. OEM measured with P-Gear 610 on always the same route without downhill or uphill gradients. The same temperature and air pressure as possible. You can't do it much more precisely. The fact is, OEM time 100-200 km/h 8.65 seconds now 6.78 seconds. I drive 0-100 km/h without stepping on the brake at the beginning in 3.57 seconds. OEM was 4.05 seconds! I don't need any more facts. I have neither slippage nor rubber abrasion. Although I didn't switch roles because it wasn't necessary for me. I agree with you, the area of ​​the belt is reduced when the two deflection pulleys rotate. Which of course doesn't help for less slippage. I think you can talk and discuss everything to death. As long as I only drive 2-3k kilometers a year, plus 90% without full throttle, I don't think about damage to the vehicle or transmission. I'm just HAPPY, THANK YOU VAP! And no, I haven't received anything without paying until now, I'm just a normal customer.

 

Wrong. You can log charged pressure relative to RPM and other PIDs, you know the drive ratio and the kPa that should be generated. You can see the charged pressure increase and then start to periodically drop. Because...... the belt is slipping. You can subsequently see that eliminated when you fix the problem. It's only a guess if you don't have the data and don't know how to interpret it correctly.

Correct. That's why we developed a proprietary datalogging tool, and why we test all our products (we don't test them on the road however as it wouldn't be safe or responsible to do what we need to do on public roads. We use an airport runway instead.)

 

Oh for christ' sake, i'm not going to dig through my inbox to get his exact verbiage..Stop splitting hairs and antagonizing everyone. I don't recall saying I was a beta test either for the datalogger, the software was polished, worked fine out of the box and pinpointed the anomalies associated with my setup. Don't put words in my mouth, thanks. End of the day, they came back with results, not excuses.

 

I said that I would let this be but here we go again with nonsense.

Yes, one can detect possible abnormalities based on readings from other sensors. BUT, the only accurate way to pinpoint exactly belt slippage is by having a speed sensor on the supercharger shaft, PERIOD. A small hairline crack in the upper intake manifold would show the exact same behavior on the datalogger, the same applies to a small leak on the MAP or MAT sensor thread... or a failing gasket on the upper intake manifold. As you can see, you can make "educated guesses" but accuracy matters and certainty is critical in developing a product for long-term consumer use.

To state that the datalogger can accurately detect BELT SLIPPAGE based on a PID reading is inaccurate and false. No doubt, it can help, but then again an iCarsoft LR 2.0 (inexpensive) can read and store all of the same parameters.

Stuart, please, let's not keep on going with this. The points were, swapping the idler pulleys reduces the wrap angle of the belt @ the supercharger pulley and it's detrimental. #2, no datalogger can accurately read/detect belt slippage, it may give some hints but NOT confirm or RULE OUT with certainty.

We can agree to disagree with this, but providing accurate technical background to the forum users is key. This is in no way an attack on your company or you but it's something that needs to be considered when somebody may deploy this modification and it can detrimentally affect them.

I know this forum is the VAP* cult follower shrine, but facts are facts and integrity should still be maintained by all.

 

It's not an attack but yet you consistently choose to use the word nonsense?

I have only 2 things here that need to be communicated clearly to our customers, which are being called into question:

1. There's no concerns about belt slippage with our Griptec pulleys, whether you swap the idlers or not.
2. Sure, you can come up with all kinds of other things like cracked manifolds and play the 'what if' game. However, the bottom line is this - we logged data. We observed in that data, problems that appeared to be belt slippage. We created a solution to belt slippage and it fixed the problem. 100%, what we observed in the data was a result of belt slippage, and 100% it was fixed by our solution. And what you're concerned with is that *technically* we didn't log belt slippage because we don't have a sensor on the pulley? We observed it through other data, and that observation was 100% correct and borne out by our solution. And then verified on multiple cars. So what useful contribution are you making by starting an argument about it? Zero.

 

With no test setup, no lab, no technical background, a dumb rider like me can tell for myself that the new upper ribbed pulley is significantly better than the OEM pulley in terms of slippage. When I unpacked the new pulley and put my new belt over it, I knew it could help. It's just way more grippy than the original. I don't know if this is still the case after 10k kilometers. But I'll find out in 5 years :-) So I really don't care how you can measure something or not.

 

 

I think that you posted this in the wrong place. The is Jaguar Forums not Amazon returns or reviews for your recently purchased/used device.

 

No it is absolutely in the right place.

 

Well, then, thank you for sharing your suggested tool to address a belt fitment issue or perhaps a belt slippage detection tool. Since you have such a tool on hand, can you elaborate on how it's used with the issue at hand?

 

It is a very sensitive BS detector.