From my experience I think it's two or three days.
Moral of the story - get it right the first time and check and check again before you hit the Submit button!

 

I'm confused by the high torque. My V8 S dynojet dyno calculates the same WHP but with way less torque. Obviously the RPM range is the same and since HP is calculated from Torque * RPM, not directly measured, one of the two dynos seems off. These engines aren't known to generate more peak torque than HP, so I think something is wrong with your plot.

This is with Racechip Map 7 and a SC pulley (blue, green) vs a SC pulley on an otherwise stock car (red).

 

I suspect the VAP torque scale is in Newton Metres (Nm) rather than the antiquated foot pounds (ft/lb) you Yanks still use!
1 ft/lb = 1.3558 Nm.

 

Its only 560 vs 520 though, no where near 1.36x.

 

The curves look correct (whp vs lb-ft) as they appear to cross at 5252 rpm.

 

Horsepower is calculated by torque at that RPM specifically. The VAP tune makes more mid-range horsepower than the Racechip tune, which is why you're seeing higher torque figures. There's no doubt in my mind that the VAP tune has more development hours and fine tuning than Racechip does; probably were able to make some notable mid-range improvements.

 

Duplicate

 

Its possible that there is more mid range torque which allows thhe engine to develop more, or equal, peak torque to HP.

But then two questions jump out: why doesn't the stock tune have the same equal torque/HP profile, and, why does VAP develp less torque than the stock tune at high rpm?

A third question is Racechip adds around 10%, the VAP tune adds 15%. Thats believable, but for the fact the they develop the same end result, so the % difference is due to the R starting out weaker than the V8 S.

​​​​​​A fourth question would be why the Racechip torque is very flat, explaining a very constant slope HP curve since HP = Torque * RPM. But the VAP torque curve is heavily bowed, but the HP slope remains fairly constant, which requires a flat torque curve.

 

I imagine it is because Jaguar is limited by the ZF transmission. The transmission in our cars is rated by ZF for 700nm or 516 ft lbs. Jaguar would not be able to go above 516 ft lbs. (exactly what the SVR makes) without being on the hook for transmission warranty instead of ZF.

I'm not sure where you're seeing VAP's tune develop less torque than the stock tune at high RPM, because it clearly does not. If it did, it would also make less horsepower than stock.

While this is purely a guess, I would think Racechip is a lower quality tune (no offence against you choosing them) than the VAP tune. Lots of other companies take shortcuts to make more power and sell canned tunes, which could be less safe or efficient. This is something I believe VAP does not do; they've been extremely transparent.

See above answer. Again, just a guess.

 

All the measurements are in 'old money.' IE - the torque is stated in ft/lbs, as measured at the wheels. You're seeing 460 ft/lbs at the wheels, vs 517 ft/lbs manufacturer's stated crank output. The stock torque curve is less smooth (for a variety of reasons (and although the peak to peak gain is 20 ft/lbs at the wheels, you can see that the 'under the curve' area has more like 30-40ft/lbs at the wheels across much of the power band, and carries that larger torque & HP gain through the upper RPM.



Stock Wheel Values

Stock vs. Stage 1 (Tune only)

 

From this one you can see why the Stage 2 (Crank Pulley + Tune) makes such a big difference. While there's *only* another 23 WHP at peak compared to Stage 1, you can see how much more torque is generated through the power band. Over 100 ft/lbs at the wheels, at some points in the RPM range like 3000-4000RPM.


Stock vs. Stage 2 (Crank Pulley + Tune)

 

So there is the difference, it is the baseline car. Plus, your dyno is recording from below 2000 RPM and mine starts around 2750 which makes your torque curve look more bowed.

I went digging for my car's baseline dyno and found it in in a photo I took while we were comparing runs in the dyno bay. The blue run is my 2014 V8 S bone stock, red has a SC pulley. Obviously this is an overlay of two difference days, both were over 100F in the bay. Our torque is roughly identical, but the V8 S is making more torque below 4k and more peak WHP than the R. It had ~20K miles at the time, so it was probably at its peak performance. That's the key difference between our results.

This dyno is busy all day, so its well calibrated. We pulled up a few Z06s for comparison and they all put down ~545 WHP which is spot-on for the C7's LS, so I don't think the dyno is very far off.

The dyno operator felt my F was pulling timing near the top end, probably for too much heat and thought there was another 20 HP there if we could work the issue out. On the runs to test my SC pulley I hoped the car might not pull timing in the same way, but it did. Your stock R plot appears to have the same timing pull at the top end, which taken together with the lower end plotting, accounts for the more bowed torque curve appearance. That said, for some reason your R is generating about 30 ft-lbs less torque below 4000 RPM which isn't huge but is a little puzzling since we are comparing to a "495 HP" V8 S. Above 4000 RPM, our torque curves and values are pretty much an exact match.

I was able to solve the timing pull issue with heavier weight oil (Liquid Moly 5W-40), so I assume it was engine overheating above 6000 RPM. You might try the same. Here is my latest Racechip dyno again for easy reference to the stock tune curves, above. The red pull below is the same dyno pull as the red pull, above. The blue and green pulls are Racechip Map 7 x 2 (green is the more heat soaked) with the SC pulley and LM 5W-40 oil and there is no timing pull. All of these are the stock tune, due to the nature of Racechip.

 

So to summarize

• Our stock cars dyno about same, minus the V8 S making 30 ft-lbs more under 4K RPM
• Your double-pulley tune is generating 30 ft-lbs more peak torque than Racechip + SC pulley in the mid range RPM band
• Your double-pulley tune would likely also generate ~30 more peak HP if the stock and tuned car wasn't overheating above 6000

Bottom line: Stronger film strength oil is most likely equalizing our top end HP.

 

I don't think the two cars are making close to the same power. Saying they 'both dyno about the same' really isn't accurate. You can't really compare final numbers from two dynos effectively, let alone a loading dyno compared to an Inertia dyno. The only thing that really matters is the Delta - how much did you gain.

In your case, your basline of a 495BHP 'S' is 487BHP? I'm assuming that is crank HP, if it's wheel HP you're only showing an 8% drivetrain loss. Either way, you've gone from 487 (let's say WHP) to 559WHP. A gain of 72WHP on a car that's factory rated at 495, and you're showing a drivetrain loss of 8% on that particular dyno so around 78 BHP at the crank, to total around 573BHP in addition to your factory rated 495.

Our 550BHP factory rated 'R' went from 464WHP to 557WHP, a gain of 93WHP. At our measured drivetrain losses that puts crank output at 660BHP. So based on the drivetrain losses versus manufacturer's stated outputs and adding in the deltas for each respective car, they are almost 90BHP apart.

It also started with 55BHP more than your S. The fact that your 495 factory rated 'S' put down 23WHP more on the Dynojet Inertia dyno, than the 'R' did on the Superflow Loading dyno just goes to show you that you can't really compare the two directly in terms of final numbers, you can just measure gains. On the Superflow, we used, I would expect your car to baseline at around 417WHP.

 

This is all WHP. I think -8% is pretty reasonable for a ZF8, I've seen documentaries claiming 7-8% losses. Even a modern double shaft dual clutch can achieve close to the old 15% guideline.

I have to disagree that "rated HP" is a good baseline, otherwise there would be no dynos. Also, the hardware is the same with the V8 S and R, only the software upper end limits are different, so the OEM rating is not relevant when changing the upper end limits via modifed software. I think thats apparent with the stock S being slightly stonger than this particular R in low band RPM and the same to better in mid and high band. Since a dip in the R's torque curve is the disadvange, not the height of the same shaped curve, it seems clear this is a car sample difference.

The two engines are identical starting points pre-tuning, so VAP claiming an 55 extra HP from the OEM tune, when that tune is no longer in place, seems optimistic.

It does appear that VAP with two pulleys is making 30 ft-lbs more torque than RC + SC pulley and therefore more HP, until timing is pulled above 6K, much like my car did. That is probably easy to turn into 690-700 BHP with a proper oil for a boosted engine pushed to its limits.

So VAP and its ability to integrate two pulleys definitely makes it the stronger tune.

Another lesson learned is using a proper weight oil is the best "Stage 1" aftermarket tune for the F, and will likely net an additional 20-25 HP above 6000 in addition to longer service life.

 

Thanks for posting the graphs.

There seem to be large range of numbers used for drivetrain loss so, out of interest, what drivetrain loss did you measure and how did you do that? If my maths is correct your numbers imply 15.5%?

 

Absolutely not reasonable. Even if you took the transmission out of the equation entirely it would probably be more than 8% drivetrain loss. It takes a lot of power to spin all the weight at the wheels/tires in addition to the driveline itself.

Dynos are strictly to provide horsepower delta, just as Stuart said. You absolutely CANNOT compare dynos to one another; especially two different types. Go research Mustang dynos vs. the competition and you'll find articles documenting the massive differences in horsepower readouts on the same vehicle. Your argument here is flawed and you need to get a little more educated on the subject. I feel like you don't have a complete grasp of what's going on.

You have no evidence to back this up. You made one dyno run that showed "improvement" and have no data regarding engine life.

 

There is a number that is correct. Simply claiming that all numbers are wrong is obviously not that correct answer.
The dyno numbers match perfectly, its the shape of the curves that don't match. Comparing the relative shape of the curve is the comparison that you are advocating. We are making the exact same argument.
I already posted the dynos that show my car not overheating with more HP and oil weight as the only variable. Stuarts baseline and tuned R displays the same fall off. I think you are the only one giving an opinion without proof.

 

Wondering if anyone else has any feedback on using 5w-40 oil? Might be a useful switch for those of us in hotter climates.

How come you didn't use Castrol Edge Pro 5w-40 with the titanium content that's apparently favourable for our engines? Out of curiosity

 

​​​​​​Only because its a premium oil that isn't too pricey. Mobil 1 0W-40 Euro was an even better value at $24/change but I prefered the 5W startup weight. LM also has a reputation for going easy on cats vs RP and Mobile 1.

I am a firm believer in changing the oil to filter it, so value matters. I change my oil every 1500 - 2000 miles and change the filter every 10K. I think soot and pulverized metals smaller than the filter catches are responsible for most wear.

I know thats a different issue than preventing overheating above 6000, but for that any good proper weight oil will do.