VAP Tune- and no, I'm not sharing it...

[c131frdave]

I recently gave up on trying to figure out how to tune my F-Type R and purchased VAP's tune with pulley upgrades. I accidentally ordered the wrong bottom pulley, so all I have right now installed is the top pulley and the tune itself. I spoke with the guy who wrote the tune and he said it was fine to run it this way with the tune as-is until the bottom pulley arrives.

First, VAP says, and I agree, that many parameters that VAP changes to increase power are missing with HP tuners. However, there are quite a few important parameters available for tuning with HP tuners that would be helpful. I can't show you my tune. Truth be told, I paid a lot of money for it, so I'm not really willing to just give that away anyway- but if I did, I could get sued. So don't ask. The answer is no- sorry.

That being said, it is pretty obvious what Jaguar does to these engines when they put them in different cars with different HP numbers. This engine, no matter what car it's in, is capable of at least 600hp (crank). Looking at the VAP tune, all they really do is raise the limits on the higher RPM bands for your primary tables like boost limits, driver demand, torque control, and fuel parameters (for the most part). Jaguar (and Land Rover) simply retard the top RPM bands to whatever degree they need with all of these parameters. VAP uses WinOSC to do their tuning- I think he said he does over 90 tables in WinOSC for their tune (which is interesting because I count 91 tables in HPTuners that have been changed..). The pops and bangs mod VAP does is not in HPTuners (he told me how he does it), so I'm guessing when he says 90 tables, he's counting the group of tables as one table instead of six. HPTuners needs to add a lot of points in their poling before it will equal WinOSC. I'm not sure why they didn't- the Fords that use this ECU all have MANY more points than the Jag/LR list of points. I wish they would at least try to make the tunable list more complete.

My point of the post is, I do think you could use HPTuners to unlock much of the potential of this engine if you know what you are doing (which I do not...). I still think there is some locked-up power left to get even with my VAP tune- timing, for example, is still only 25.5 degrees WOT at 6000 RPM, and I know of a couple people that run 27 degrees of timing for maximum power on 93 octane. VAP can't sell a tune that will blow up your car, so I think I can push it just a little bit more here and there if I wanted to. Keep in mind, though, that there are 90+ tables to look at before you are going to get anything close to a VAP tune. But it's doable to a high degree.

[c131frdave]

On the other hand....

VAP does use HPTuners for transmission tuning. Apparently HPTuners is the best software readily available for ZF 8HP transmissions. I spent quite a lot of time watching videos- mostly dodge videos- on how to tune this transmission. I've had lots of offers from tuners to tune my transmission. I decided yesterday to try it myself, only I took a different approach. As far as I can tell, there are two modes to this transmission, normal and performance. There appears to be several shift aggressions and shift schedules, though I couldn't figure out which one was using what shift schedule, so I just made them all the same for upshifts.

I like the way the transmission shifts in Sport mode when you push the shifter to the left when in drive (I have an F-Type R V8). I don't like the Sport mode's way it keeps the engine in the power band (2000-6500) all the time when driving on the street. Sport mode is perfect for road racing, but it's a little annoying driving around town unless you are treating your roads as a race track. Country driving on windy roads is a perfect environment for Sport mode, but I mostly keep it in regular (normal) Drive mode with the shifter to the right side.

So after watching several videos, I learned what does what in the transmission tune, for the most part. Luckily the Dodge transmission and Jaguar transmission are almost exactly the same with their tables and tunables. I then compared the tables between normal mode and sport mode for shift pressures, torque management, and several other things and learned that Sport mode is MUCH more aggressive with it's settings. So as a starting place, I simply copied most of the Sport mode setting tables to normal mode- sort of. I copied all the values above about 50% torque, and then smoothed the transition between the bottom and top. I did not change the torque management at all, which I'll get into later. I also changed the maximum torque to match what VAP set for the engine +1%. The transmission appears to have final say on how much torque the engine can put through it.

My last change was shift schedule. Stock from the factory, the transmission is programmed to shift at 6500 RPM, and the computer does something interesting when it shifts: at about 6300 RPM, Torque Management kicks in, timing is pulled, the throttle is mostly cut, probably the transmission partially releases the clutch (slip) that the gear is in, and it sort of glides up to 6500 RPM from momentum before hitting the next gear. So really it is shifting with full power on at about 6300 RPM. Having seen several graphs of the dyno runs of engines with the same mods mine has, the power really doesn't peak until 6500-6600 RPM or a little bit higher. Ideally, you would want to use as much power as you can for as long as you can, so I changed the shift schedules to shift at 6700 RPM. I left first and second to shift around 6500, and then took the rest of the gears to 6700. Using VCM scanner, it now kicks in torque management at just over 6500 RPM to make the shift, using more power than before longer (the next gear comes in at a higher RPM).

I left torque management unchanged. I was reluctant to do this at first because Performance Mode actually has more torque management than normal mode. Having moved all of the other settings in normal mode up to Performance mode settings, I probably should have upped the torque management as well, but I forgot about it when I first tested it... Anyway, my best guess is that with more aggressive shifting parameters in Sport mode, Jaguar increased the torque management to keep from excessively stressing the transmission and increasing drivability. When I did my final testing with the lesser torque management, the wheels chirped a bit on each shift up to 4th. My car is AWD, so that's saying something. I think the less torque management is increasing the power after shift, causing the chirps.

Results were astonishing (to me). It was near 90F yesterday when I did all of my trans mods. Before programming the transmission, I was doing 0-60 runs 3.7-3.9 seconds. After the mods, 3.3-3.4 seconds. In Sport mode the best I did was 3.5 seconds, holding the break and revving to 2200 RPM for the launch. Right now, my regular Drive normal mode (with dynamic mode on) is quicker than any other mode, and it is still smooth as ever for normal driving. I think it is so quick under WOT because of the reduced torque management. That's pretty impressive. I've heard you can knock off .5 seconds of your 1/4 mile time with just a transmission tune, and I believe that's correct. That may be worth as much as a pulley upgrade and tune! Right now I'm about .2 seconds quicker than stock Sport mode, which I'm quite happy with. I may bump it up a little bit after I get my crank pulley- we'll see how it goes. If I'm running 3.1 or better 0-60, I'll probably just leave it as is.

The video that I found most helpful was this one, though I actually did none of what he did in the video. The important part of the video is that he sort of explains what each table does, to a certain extent. When he would go to a table and explain it, I would compare Performance mode and Normal mode, which is what gave me the idea to combine the two. My thought was that Jaguar wouldn't put settings in Performance mode that would damage the transmission, so I figured I would use that as a base line. It turns out that I'm pretty happy with the base line, and likely will leave it like that. But I thought I'd share this with you guys since trying to figure out how to tune these cars has been such a struggle for me. I've had my F-Type for almost a year now, and there's virtually no help out there on how to tune our cars.

Anyway, I hope you all find this helpful and encouraging. Don't be afraid to watch Dodge Hellcat transmission tuning videos since they use the same transmission (basically) and have many like- settings. I think the car he was tuning in the video I linked was a Jeep or something, in fact. There's information out there, you just have to be a little bit unconventional digging it out.

[GrannySShifting]

Do you have any datalogs you can post, Ive been curious as to what data streams and sample rate HPT gets on these?

Also curious as to what headroom is left in the injectors and fuel pump on them. e85 would do wonders on those things!