Chiptuning "ZF8HP Gearbox tuning Alfa Romeo Giulia & Stelvio Quadrifoglio"
The 8-speed automatic gearbox of the acclaimed gear manufacturer from Friedrichshafen (Zahnradfabriek Friedrichshafen) is known as bulletproof. First used in 2008, the ZF8HP automatic transmission is now used by almost the entire automotive industry with a torque ranch from 300 to 900 Nm.
What kind of meaningful adjustments can you make to the TCM software?
Well, that is a good question. Both the Giulia and the Stelvio drive very well from the factory. The engineers did a great job. So, what can still be improved? We’ll read about that later. First a little technique.
You should be realize that a gearbox is something completely different compared to an engine. Pretty much all our experience with engine tuning can be put aside. We started with a blank sheet of paper. We know “quite well” how an engine works. But how does an automatic gearbox actually work? Apart from the basic knowledge, we didn’t know very much about it. So first we had to dive into the books. You can’t work on software without knowing the mechanics. Same as for engine tuning.
Engine tuning is about turbo pressures, ignition timing and fuel quantities. With gearboxes, it is about disconnecting and coupling transmissions. The 8-speed has 5 clutches that are controlled by hydraulics. With those 5 couplings, 8 different gear ratio’s can be made. In addition to these clutches, there is also the torque converter (think of this as the clutch on a manual gearbox).
In terms of software, there are countless maps that tells everything about internal oil pressure (hydraulics) and disengage and engage clutches, torque limiters and shift times. Countless strategies which can be set on or off, reference maps. Groups of maps apply to each possible gear change. Groups of maps apply to each DNA position. Groups of maps apply to the driving style (acceleration, braking, lateral forces, uphill, downhill) etc. etc. In short, an endless list of maps.
But there are even more differences. When it comes to engine tuning we use a lot of diagnostic equipment with which we can read about every possible engine parameter. As a result, we know exactly what is happening and whether a software adjustment has the desired effect. Unfortunately, that turns out to be different with gearboxes. For ALfa Romeo the available parameters are very limited. It became clear that feedback had to come from driving the car on the public roads and paying attention to how the shifting is done and feel what the gearbox does. Even a dyno doesn’t offer a solution here. On a dyno the car is stationary. So no acceleration or lateral forces. Which are both used for shifting points.
Fortunately, we did have access to other very valuable information. We will not discuss this in detail here, after all, the competitors also reads along.
Each TCM software contains an average of about 100 different shifting point maps. These are the maps that show when up- or downshifting takes place. These shifting point depends on the accelerator pedal position and the output shaft speed of the gearbox. That last one only is already a tricky one. As a driver you have no idea about this rotation speed. Do you? As a driver you do know the engine speed. Simply because it is indicated on the rev counter. In short, to make the switching map more transparent, we had to have a conversion made in our own data analysing software, Since we made this software ourselves, that was easy to do. The pictures below show the result.
But how do you know which of the 100+ shifting maps is used under which circumstances? That was partly described by the additional information we had. But unfortunately that turned out not to be complete either, which ultimately comes down to a lot of trial & error and logical thinking. Eventually it all became clear to us.
We are not going to make an attempt to make the gearbox faster switching times. We read everywhere that many “tuners” promise this. However, we also know that they work with certain information supplied. We have also studied that information and our conclusion is that this will not lead to faster switching times. It can provide the feeling of faster switching times. Basically what they are trying to do is to increase the hydraulic pump pressure. This would allow the clutches to move faster, but it will mainly result in a rougher engagemen of the clutches. Which results in discomfort only as far as we are concerned.
The real switching times are made up of many sub-actions. Every gear change of every gear of every DNA/R position has its own set of actions. This is so complex and precisely tuned that we have no illusions that we can improve it. So we don’t.
Gearbox software also uses torque limiters. However, for our Alfa’s they are at such a level that they are not a limitation, even with a good engine tuning added. We have not yet come across any software where there is a real limitation.
There are also torque limiters that come into effect when there is a malfunction or when the gearbox oil temperature rises too high. We do not adjust these. In our opinion, that is not wise to do.
The absolute RPM limiters
Raising the absolute rev limiter may be necessary if the rev limiter has been raised in the engine software. If this limit is exceeded, it is accompanied by quite a dramatic effect. A literal hard limp home. Not pleasant. We will increase this according to the needs of the engine tuning
Automatic upshift in Dynamic/Race when shifting manually
When the gearbox has been set to manual, it automatically switches up in the A and N position when the rev limiter is approached. This is very useful because in low gears the RPM increase so fast that you are simply too late to upshift youself. However, this does not happen in Dynamic and Race. As a result, you will hit the rev limiter and therefor a drop in speed. Sprint lost.
We have put a stop to that. In Dynamic and Race, the gearbox now switches to the next gear just before the rev limiter to be able to continue progress immediately.
What is our focus?
We focus on switching points in all DNA positions and eliminating some inconveniences. Adding meaningfull Race Mode shifting when Race Mode is configured. Activating shifting paddles when needed (in Race Mode). Everything aimed for more driving fun.
How does this manifest itself in real life?
Engine tuning means generally more torque and power. Everyone can imagine something about that. It will provide faster acceleration.
However, we have noticed that it is difficult to imagine something with our gearbox tuning. As indicated earlier, we focus on modified switching times. This can best be described with the word “eager”. The car responds more quickly to accelerator pedal movements. The car doesn’t feel so lazy anymore.
One can also look at it differently. Suppose you drive in Dynamic. That already drives quite eagerly (if one doesn’t know any better). You then switch to the A position. The car feels noticeably lazier and more sluggish. Approximately the same difference is added to the Dynamic after the gearbox tuning. This is also noticeable when switching back from the new Dynamic to the N position. The N position has become the old Dynamic. The new N-mode/old D-mode suddenly feels lazy/slazy again. Strange but true.
We have also realized that people are often inclined to give a lot of gas when a lot of acceleration is required. This is somewhat logical because one wants to encourage the gearbox to downshift (kick down). After tuning, the need is much less because the driver now almost always drives one gear lower than before. The result is that the torque at the wheels is now higher than before. It is therefore not necessary to downshift. The car accelerates more easily. It is therefore no longer necessary to give a lot of gas. One now has to let the gearbox do the work and not so much the engine.
- The new A position (old N position with minor adjustments) is intended for quiet driving.
- The new N position (old D position) is intended for normal traffic.
- The new D position is intended for real steering work. The revs are kept higher so that the engine is at the beginning of its maximum torque range. The turbos can then spool up much more easily. The engine is always ready to GO. Intended for roads with many variations. Lots of braking, acceleration, nice cornering. Real dynamic driving. Less suitable for highway traffic. The revs are often unnecessarily high. Unless one is “hunting”.
- Race Mode is largely unchanged. Except for a faster kickdown reacton
What customers say about it
“The car is, as it were, woken up from a coma”
“It feels like I got a new car”
“I’m getting that old Alfa feeling back again, a lovely revving engine”
“Indeed, EAGER is the best description”
“I don’t drive the car anymore, I play with it now. What an experience!”
“This is how a real Alfa should be”
- Shift moments from A replaced by those from N
- Shift moments from N replaced by those from D
- Shift moments in D replaced by a milder Race Mode shifting
- Race Mode shifting unchanged
- Increased maximum upshift RPM (7250 RPM)
- Added auto upshifting in Dynamic/Race while in manual @ 7250 RPM
Price and request
There are 2 options to get this type of chiptuning
1) By visiting us with the car.
2) By contacting one of our resellers
The prices below are including 21% TAX.
Outside European Union costumers can subtract 21% TAX.
Squadra ZH8HP tuning Giulia/Stelvio Quadrifoglio
€ 590 ,-
Engine and gearbox tuning + Performance Logger Full SD
Yesterday I finally got the chance to drive the car properly. My first impression is that the car is great, thank you! I could definitely notice the improvements in D now too. But especially as you say, everything seems to work so much better in Auto mode on the gearbox. The car was boring compared to now in automatic mode. You had to drive in manual mode to bring any fun. But now, manual driving seems slow. That's how good automatic mode has become.
I also feel that the electronic steering struggles to work adequately in D. Not only in 1 and 2 but now also in 3, as the power and torque increase to such an extent that the rear end still slips even in D!
All in all the car feels fantastic and from what I could monitor via the Performance Logger on the display, the oil, gear and differential temperatures seem great. However, it was not a hot summer day here, with temperatures around 20 degrees Celsius.
The next big test will be at the end of March when I take her to the track. Will report back later.
Thank you again for making this possible, I am forever grateful.