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Description
APR Valve Springs/Seats/Retainers - Set of 40The APR Valve Spring System is a high performance, lightweight upgrade designed to increase valve control and eradicate valve float common on many applications. APR's design specifications called for a valve spring, retainer and spring seat combination that doesn't overpower and snap the OEM valves or erode the aluminum spring seat, while still maintaining exceptional valve control. The result is an advanced design that's 28% lighter yet 20% stiffer
The APR Valve Spring System is a high performance, lightweight upgrade designed to increase valve control and eradicate valve float common on many applications. APR's design specifications called for a valve spring, retainer and spring seat combination that doesn't overpower and snap the OEM valves or erode the aluminum spring seat, while still maintaining exceptional valve control. The result is an advanced design that's 28% lighter yet 20% stiffer than the high performance OEM Golf R setup and is proven to eliminate the OEM valve train's weakest link. We call it Performance Without Compromise!
Valve Springs:
Weight reduction, and not necessary stiffness, is absolutely necessary to increasing valve control. The APR Valve Spring utilizes a beehive design that allows for a reduction in mass in not only the spring itself, but also through use of a smaller titanium retainer. The springs feature an ovate wire design that allows for even stress distribution resulting in better control at high RPMs through a resistance of harmful valve float inducing harmonics. The lightweight design also accomplishes accurate valve control without requiring an overly stiff spring which has been proven to snap OEM valves in half. Each valve spring weights 29 grams and represents a 19% weight reduction over the OEM Golf R spring. The result is a highly engineered design that's simply plug and play!
Valve Spring Retainers:
Through the use of a beehive design, APR's Engineers were able to design and supply a valve spring retainer that's smaller than stock to reduce weight as much as possible. In an effort to offer extreme weight savings, at an additional 71% over the OEM Golf R retainers, American 6AL4V titanium was used for its high specific strength weighing in at only 2 grams each. By offering outstanding weight savings, exceptional valve control characteristic are achieved while only requiring a modest 20% increase in stiffness over the OEM Golf R spring.
Valve Spring Seats:
Often an overlooked piece of an upgraded valve train is the valve spring seat. The factory heads are aluminum, and unfortunately increased spring pressure can distort or erode the mating surface overtime as they mate directly to the bare head. To prevent this from happening, APR's Engineers designed valve spring seats out of 4140 heat-treated chrome molly steel with a black oxide coating. The spring seats are strong enough to withstand pressure from the springs and provide a mating surface that evenly distributes spring load across a larger area than the spring it self, allowing an increased spring rate without negative side effects to the aluminum head.
Eliminating Valve Float:
It's not uncommon to experience valve float with the OEM valve springs, even below the OEM rev limit. On some applications like the 2.0 TSI, back pressure from the K04 turbocharger has been known to force the exhaust valves open. This has been noticed on vehicles with overly weak OEM valve springs and some with higher miles that have simply lost their stiffness over time. This issue accompanies misfires commonly above 5000 RPM. In some extreme cases, valves are forced open and the vehicle ceases accelerating any further. A quick datalog of intake mass airflow and boost pressure at wide open throttle will show a sudden rise in boost pressure with an immediate loss of airflow as pressure from the open valves is pushed back into the intake manifold. On other applications, valve float can begin to occur just beyond the OEM rev limit. While other components, such as higher strength valves are often required for extremely high revving applications, the APR Valve Spring System will eliminate float well beyond the revving constraints set forth by the other components.
Valve Springs:
Weight reduction, and not necessary stiffness, is absolutely necessary to increasing valve control. The APR Valve Spring utilizes a beehive design that allows for a reduction in mass in not only the spring itself, but also through use of a smaller titanium retainer. The springs feature an ovate wire design that allows for even stress distribution resulting in better control at high RPMs through a resistance of harmful valve float inducing harmonics. The lightweight design also accomplishes accurate valve control without requiring an overly stiff spring which has been proven to snap OEM valves in half. Each valve spring weights 29 grams and represents a 19% weight reduction over the OEM Golf R spring. The result is a highly engineered design that's simply plug and play!
Valve Spring Retainers:
Through the use of a beehive design, APR's Engineers were able to design and supply a valve spring retainer that's smaller than stock to reduce weight as much as possible. In an effort to offer extreme weight savings, at an additional 71% over the OEM Golf R retainers, American 6AL4V titanium was used for its high specific strength weighing in at only 2 grams each. By offering outstanding weight savings, exceptional valve control characteristic are achieved while only requiring a modest 20% increase in stiffness over the OEM Golf R spring.
Valve Spring Seats:
Often an overlooked piece of an upgraded valve train is the valve spring seat. The factory heads are aluminum, and unfortunately increased spring pressure can distort or erode the mating surface overtime as they mate directly to the bare head. To prevent this from happening, APR's Engineers designed valve spring seats out of 4140 heat-treated chrome molly steel with a black oxide coating. The spring seats are strong enough to withstand pressure from the springs and provide a mating surface that evenly distributes spring load across a larger area than the spring it self, allowing an increased spring rate without negative side effects to the aluminum head.
Eliminating Valve Float:
It's not uncommon to experience valve float with the OEM valve springs, even below the OEM rev limit. On some applications like the 2.0 TSI, back pressure from the K04 turbocharger has been known to force the exhaust valves open. This has been noticed on vehicles with overly weak OEM valve springs and some with higher miles that have simply lost their stiffness over time. This issue accompanies misfires commonly above 5000 RPM. In some extreme cases, valves are forced open and the vehicle ceases accelerating any further. A quick datalog of intake mass airflow and boost pressure at wide open throttle will show a sudden rise in boost pressure with an immediate loss of airflow as pressure from the open valves is pushed back into the intake manifold. On other applications, valve float can begin to occur just beyond the OEM rev limit. While other components, such as higher strength valves are often required for extremely high revving applications, the APR Valve Spring System will eliminate float well beyond the revving constraints set forth by the other components.
Features:
- Increase valve train control
- 71% weight reduction over OEM Golf R retainers
- 19% weight reduction over OEM Golf R springs
- 20% stiffness increase over OEM Golf R springs
- Eradicates TSI K04 "valve float" issues
- Supports higher revving application
- Weight saving beehive spring design
- ASTM A877A OTSC round wire steel springs
- 6AL4V American titanium retainers
- 4140 heat-treated chrome molly steel spring seats with black oxide coating
- 29 grams per spring
- 2 grams per retainer
- Compatible with OEM valves
- Spring seats included to protects against aluminum erosion in the head
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4.3 ★★★★★
Based on 22 reviews
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Product Reviews
★★★★★ 5
The best DL/ML book I have ever seen!!
Format: Hardcover
Fantastic deep-learning book! The logic is very easy to follow, but the content is very thorough when it comes to explaining the theories behind it, making it perfect for beginners as well as math and CS students. The best DL/ML book I have ever seen!!
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Reviewed in the United States on November 30, 2025
★★★★★ 5
Comprehensive Look At An Incredibly Complex Topic
Format: Hardcover
Deep Learning is an advanced book with great explanations and details. There is a heavy math focus with the book's beginning chapters detailing the necessary linear algebra and probability that one will need to understand deep learning. I liked that the author's chose to cover only the parts of these subjects which are relevant to deep learning.
There are many interesting philosophical sections in the book as well. Just about when I was feeling overwhelmed with the complexity of the mathematics the authors take a step back and cover the foundations of deep learning such as borrowing concepts from human learning. There was an interesting dicussion about the early studies done on the vision of cat's and monkey's in the 1970s.
The text covers the entire history of deep learning and the bibliography is hundreds of sources. It is clear this is the most comprehensive text available about deep learning. For anybody interested in this topic this book is a mandatory read.
There are sections about machine learning as well, which makes sense because deep learning is a subset of machine learning. These sections focused on the machine learning concepts which are most relevant to deep learning.
The book was well organized and divided into three parts which cover mathematics related to deep learning, typical deep learning techniques, and then more experiment learning techniques. Often the author's state when a technique works well or when it does not, and which types of data works best for the technique.
Just a warning, the math in this book is highly complex. It requires a lot of work to go through this book, but the effort will be well rewarded.
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Reviewed in the United States on March 15, 2017
★★★★★ 4
Too Dry.
Format: Hardcover
This was a required textbook for my class in college. I think it was too dry.
The book titled Deep Learning: From Curiosity To Mastery is much more approachable.
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Reviewed in the United States on May 22, 2026
★★★★★ 5
Comprehensive! The Bible of Deep Learning!
This book has by far surpassed my expectations! I have purchased many machine learning and deep neural network books in the past, but nothing has ever come close to this book! First of all, it is written by the fathers of Deep Learning, and is therefore an authority. Secondly, the book is broken into three parts: 1. A math overview and refresher. 2. Deep Learning applications and 3. Research in Deep Learning. I can't help but go through this book from front to back. It is a smooth read, and every sentence written is meaningful. These guys know their stuff! And after you read this book, YOU WILL ALSO know your stuff!
If you feel daunted by the price, just remember, you get what you pay for! I'd say they could easily charge about $300+ for this book, but they are doing everyone a very kind favor by ONLY charging this reasonable amount. You get A LOT of bang for your buck with this purchase. I hesitated at first about buying this book because of the price, but I am soooooo happy that I did! Worth every penny! Look no further, get this book and start your Deep Learning journey!!
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Reviewed in the United States on July 14, 2017
★★★★★ 1
A rushed, poorly written guide of how the "experts" can't really explain what Deep Learning is
Format: Hardcover
This book, in every sense of the word, is rushed. I think the authors wanted to establish themselves as leaders of this young-ish field, but does so by sacrificing quality. It also shows that Deep Learning theory has been there for a long time, known by another name called Neural Networks. The interesting algorithms are of MLP, Back Propagation and the classical neural networks. The optimization methods such as Adam are the ones that are new and interesting, and the only ones worthy of in this book. So, essentially, what you get from this book is use A for X, B for Y and C for Z type of dry, un-intuitive, badly written waste of paper.
As for the structure of the book, it's like an example of how not to structure a book. It has some linear algebra, probability at the start (not good enough, and confuses more people and wastes paper). Goes on to prove other algorithms such as PCA (yeah, ok!). Then, talks about how this architecture works for this and that architecture.
So, yeah, if you really want to try out deep learning, don't buy this book. Set up Tensorflow/pytorch/ other library, run the tutorials, find an architecture for the problem you are interested in and start tweaking that. You will have far more fun and would have saved your money.
The praise that this book gets is beyond me. Did Musk even read this book? I doubt it.
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Reviewed in the United States on May 15, 2018