Christian-
Active member
Offroad Hamster is correct. A Renntech tune is a full ECU flash, which allows changing any number of ECU parameters and modifying maps. Something like RaceChip is only going to add fuel and trick the stock ECU.
Tuning for more power, with warranty?
- Thread starter TFell
- Start date
chipsterguy
Active member
See their web site.
www.racechip.us
This company wasn’t born yesterday and has been doing this in EU with Mercedes diesels for a long time. They are an alternative to ECU flash. Less able to detect (no ECU flash or indication of flash, Audi does this, dont know if Mercedes has flash counters). I own audis and ecu flash detection is a big deal in the audi/vw ecosystem. RaceChip is a good solution for Audi’s because it is not detectable via ECU flash. It can easily be unplugged to return to stock when servicing at the dealer.
Does Merc monitor ECU flash counts? If so, even returning the rentech maps to stock will not avoid this warranty denial opportunity.
Plus, Race Chip is 1/3 the cost of Rentech (>$1,000 less). So the key issues for me are (1) cost and (2) detectability / warranty denial opportunity.
Like i said above, ECU flash detection can lead to warranty denials. This is a known issue with other german auto manufacturers. This is my first Merc and i lack the knowledge about performance modification issues with Mercedes.
I’m looking for any real world experience here from someone with first hand knowledge . Perhaps forum members in Europe have more experience with RaceChip and can chime in. They seem to have greater market share in the EU.
TIA
Performance tuning – gain 30% power and torque
Your car can do more than you think. Up to 30 percent more horsepower thanks to performance chips from the German test winner RaceChip. Many makes and models.
This company wasn’t born yesterday and has been doing this in EU with Mercedes diesels for a long time. They are an alternative to ECU flash. Less able to detect (no ECU flash or indication of flash, Audi does this, dont know if Mercedes has flash counters). I own audis and ecu flash detection is a big deal in the audi/vw ecosystem. RaceChip is a good solution for Audi’s because it is not detectable via ECU flash. It can easily be unplugged to return to stock when servicing at the dealer.
Does Merc monitor ECU flash counts? If so, even returning the rentech maps to stock will not avoid this warranty denial opportunity.
Plus, Race Chip is 1/3 the cost of Rentech (>$1,000 less). So the key issues for me are (1) cost and (2) detectability / warranty denial opportunity.
Like i said above, ECU flash detection can lead to warranty denials. This is a known issue with other german auto manufacturers. This is my first Merc and i lack the knowledge about performance modification issues with Mercedes.
I’m looking for any real world experience here from someone with first hand knowledge . Perhaps forum members in Europe have more experience with RaceChip and can chime in. They seem to have greater market share in the EU.
TIA
chipsterguy
Active member
Seems this is a controversial topic. Here are a couple of videos on the topic. Seems you get what you pay for (re: tuning boxes). Detectability and warranty denials always an issue with ECU flashes (unless things really are different with Mercedes).
Tune box vs ECU flash
RaceChip on a G Wagon
Tune box vs ECU flash
RaceChip on a G Wagon
Christian-
Active member
A lot of this depends on what data is stored in the ECU and what data is read by Mercedes.
Race Chip's own website mentions that ECU data may hint at a Race Chip install. So if Mercedes sees a bunch of ECU parameters that are pointing to a piggyback box, they may still deny your warranty.
Nothing's a magic bullet. Any "tuning" is a risk if it isn't approved by Mercedes.
Race Chip's own website mentions that ECU data may hint at a Race Chip install. So if Mercedes sees a bunch of ECU parameters that are pointing to a piggyback box, they may still deny your warranty.
Nothing's a magic bullet. Any "tuning" is a risk if it isn't approved by Mercedes.
siswati
Member
If anyone feels the need for more power, I will tell you that the money I spent (twice) with Renntech was the best upgrade to my Sprinters by far. Note that I have no association with Renntech other than being a very satisfied customer for the past 16 years on both of my Sprinters.
Prior to offering their current Hand Held Tuners, you would need to do an ECU Flash either at their shop (easy for me as I am less that 20 miles away), or send in your ECU. I had both my previous T1N and on my current NCV3 ECU's flashed.
For me, here in Florida, the best thing about their tune, other than the gains in performance for these model years prior to the current model is that they were able to defeat that annoying 85mph speed limiter, which if you are in Florida is just downright dangerous as the entire traffic flow on the i95 and Turnpike is pretty much 85mph.
I upgraded the wheels and tires on both vehicles to handle the additional speed. 18" wheels on the T1N and 20" on the NCV3 - shod with Michelin Lattitude Diamaris 255/50/20. Current wheels are 20"x 8.5" with 35mm offset and have 0.1" difference in rolling radius and my speedometer reads approximately 1% faster than true speed. Tires are XL rated (2271lbs per wheel), and are Y rated (186mph).
Now it is so easy to make lane adjustments, just gas it, accelerate past the guy holding you up, and move back into the lane at your preferred speed, never worrying that if the guy you are trying to pass, speeds up, then you are stuck next to him in the fast lane with 20T Mack Trucks barreling down on you and you have nowhere to go.
To say that the ECU tunes completely transformed my vehicles is to totally understate what they did. Both the HP and TQ gains make passing so effortless, and driving so enjoyable. I had a 2mpg improvement on my T1N but had a 2mpg reduction in fuel economy on my NCV3, but I do spend a lot of time at high speeds. Both vans were able to get slightly above 100mph, but the Sprinter has the aerodynamics of a brick and that's all she's got.
Unfortunately Renntech has not cracked the encryption for the current model and top speed is limited to 90mph, but that should be sufficient for Florida traffic. I plan on picking up a new Sprinter any day now and will probably stop by Renntech on the way home!
And bye the way, my service manager knows I have the tune, and it has never affected any warranty issues, and I have a label under the speedo that reads "Renntech Tune - DO NOT FLASH ECU"
Prior to offering their current Hand Held Tuners, you would need to do an ECU Flash either at their shop (easy for me as I am less that 20 miles away), or send in your ECU. I had both my previous T1N and on my current NCV3 ECU's flashed.
For me, here in Florida, the best thing about their tune, other than the gains in performance for these model years prior to the current model is that they were able to defeat that annoying 85mph speed limiter, which if you are in Florida is just downright dangerous as the entire traffic flow on the i95 and Turnpike is pretty much 85mph.
I upgraded the wheels and tires on both vehicles to handle the additional speed. 18" wheels on the T1N and 20" on the NCV3 - shod with Michelin Lattitude Diamaris 255/50/20. Current wheels are 20"x 8.5" with 35mm offset and have 0.1" difference in rolling radius and my speedometer reads approximately 1% faster than true speed. Tires are XL rated (2271lbs per wheel), and are Y rated (186mph).
Now it is so easy to make lane adjustments, just gas it, accelerate past the guy holding you up, and move back into the lane at your preferred speed, never worrying that if the guy you are trying to pass, speeds up, then you are stuck next to him in the fast lane with 20T Mack Trucks barreling down on you and you have nowhere to go.
To say that the ECU tunes completely transformed my vehicles is to totally understate what they did. Both the HP and TQ gains make passing so effortless, and driving so enjoyable. I had a 2mpg improvement on my T1N but had a 2mpg reduction in fuel economy on my NCV3, but I do spend a lot of time at high speeds. Both vans were able to get slightly above 100mph, but the Sprinter has the aerodynamics of a brick and that's all she's got.
Unfortunately Renntech has not cracked the encryption for the current model and top speed is limited to 90mph, but that should be sufficient for Florida traffic. I plan on picking up a new Sprinter any day now and will probably stop by Renntech on the way home!
And bye the way, my service manager knows I have the tune, and it has never affected any warranty issues, and I have a label under the speedo that reads "Renntech Tune - DO NOT FLASH ECU"
chipsterguy
Active member
@siswati, its good to know that your service manager is good with it. I may mention Rentech tunes to my local MB service manager and see what he has to say about it.
Major potential issues, I suppose, could be emissions issue due to tune... and would hate to have a warranty claim due to a tune on such expensive repairs. Well, at least this would be the risk that I am aware of going in...
Major potential issues, I suppose, could be emissions issue due to tune... and would hate to have a warranty claim due to a tune on such expensive repairs. Well, at least this would be the risk that I am aware of going in...
OffroadHamster
Well-known member
Ok, I am going to throw my hat in here, but first a little background on my automotive history.
I have been building and tuning cars since I was 16, not to disclose my age here but that's over 20 years. I understand and can tune multiple philosophies including speed density and MAF. I have done tuning on Megasquirt and AEM standalone systems as well as open source OBD2 systems like RomRaider. Ive owned and tracked Porsches, Mazdas, Subarus Fords and a Tesla. Back of the napkin I've spent around 700K on cars and motorcycles since I bought my first car at 14. I currently have an STi Swapped 2.5RS Impreza Coupe that makes 480whp (tuned by me) which runs circles around my Model 3 Performance.
There will always be companies that sell piggyback systems. They will always claim that they are safe and just as good as a full flash tune. And they will always be wrong. As a tuner, I would not touch a piggyback system with a ten foot pole. Most of the arguments against them have been well articulated in this thread. But Ill lay out one final one:
Technical Expertise. It takes a very thorough understanding of computer programming, tuning logic, control systems, electronics and physics to create and implement a good flash tune. It takes a decent understanding of electronics to deploy a piggyback tuner. The reason that piggyback systems are so prevalent, and that the companies that make them support dozens of brands and hundreds of vehicles, is because they are cheap and easy to develop and don't take a lot of technical expertise. This is in contrast to a flash tune, which requires a tuner to crack a manufacturers security protocols, discover and map out the environment inside the ecu and understand the complex tuning logic sufficiently to edit parameters without blowing up an engine, must be done for every single car, and sometimes multiple times across cars as manufacturers change ECU's, logic, coding, and security across model years. Most prominent tuners will focus on a single brand, and often even just a single model. Renntech is a giant in the tuning industry and builds some of the fastest Porsches and Mercedes out there. They are akin to APR, Cobb or Dinan. They build tunes and hardware that are TUV approved (basically one of the most involved government approvals for aftermarket equipment on the planet).
I am currently running a bench flash (remove ECU, hook up to it, flash the ECU, and reinstall), and now that Renntech has a full obd2 tuner will be abandoning the money Ive already spent and going that route. There is NO WAY, None, Zero, that I would put a piggyback system on a car, MUCH LESS a $100,000+ sprinter.
I have been building and tuning cars since I was 16, not to disclose my age here but that's over 20 years. I understand and can tune multiple philosophies including speed density and MAF. I have done tuning on Megasquirt and AEM standalone systems as well as open source OBD2 systems like RomRaider. Ive owned and tracked Porsches, Mazdas, Subarus Fords and a Tesla. Back of the napkin I've spent around 700K on cars and motorcycles since I bought my first car at 14. I currently have an STi Swapped 2.5RS Impreza Coupe that makes 480whp (tuned by me) which runs circles around my Model 3 Performance.
There will always be companies that sell piggyback systems. They will always claim that they are safe and just as good as a full flash tune. And they will always be wrong. As a tuner, I would not touch a piggyback system with a ten foot pole. Most of the arguments against them have been well articulated in this thread. But Ill lay out one final one:
Technical Expertise. It takes a very thorough understanding of computer programming, tuning logic, control systems, electronics and physics to create and implement a good flash tune. It takes a decent understanding of electronics to deploy a piggyback tuner. The reason that piggyback systems are so prevalent, and that the companies that make them support dozens of brands and hundreds of vehicles, is because they are cheap and easy to develop and don't take a lot of technical expertise. This is in contrast to a flash tune, which requires a tuner to crack a manufacturers security protocols, discover and map out the environment inside the ecu and understand the complex tuning logic sufficiently to edit parameters without blowing up an engine, must be done for every single car, and sometimes multiple times across cars as manufacturers change ECU's, logic, coding, and security across model years. Most prominent tuners will focus on a single brand, and often even just a single model. Renntech is a giant in the tuning industry and builds some of the fastest Porsches and Mercedes out there. They are akin to APR, Cobb or Dinan. They build tunes and hardware that are TUV approved (basically one of the most involved government approvals for aftermarket equipment on the planet).
I am currently running a bench flash (remove ECU, hook up to it, flash the ECU, and reinstall), and now that Renntech has a full obd2 tuner will be abandoning the money Ive already spent and going that route. There is NO WAY, None, Zero, that I would put a piggyback system on a car, MUCH LESS a $100,000+ sprinter.
Christian-
Active member
Well said.
IMO the ONLY viable option is Renntech if you want to mess with the ECU. Whether or not that voids the warranty is still an up in the air question, though.
IMO the ONLY viable option is Renntech if you want to mess with the ECU. Whether or not that voids the warranty is still an up in the air question, though.
OffroadHamster
Well-known member
Many ECU's have a flash counter which logs how many times the ECU has been flashed. ECU will also clock miles since last reset which will happen when you flash or disconnect the battery. Renntech allows you to flash back to stock prior to taking the van in. However dealer may question the flash counter or reset clock. The latter is easily explained, battery often gets disconnected for working on the rig, I disconnect my main when I am leaving the van parked somewhere it could get stolen. Most dealers wont nose too much into either and approval or denial of warranty claims is ultimately up to the dealer first, and mother Benz second.
IMHO, OBD2 flash tuning is very low risk WRT warranty claims. I have blown up engines and successfully had both porsche and subaru replace long blocks and short blocks in tuned cars. Porsche knew my car was tuned, subaru did not and I had no qualms about lying to them because they have knowingly sold the EJ motor with a critical flaw (well actually 3 critical flaws) that frequently lead to motors grenading, tuned or not.
My van has an OETuning tune, and I recently had some warranty work done on some emissions equipment. The first thing I told them was, dont flash my ECU, it is tuned. They still covered me under warranty.
IMHO, OBD2 flash tuning is very low risk WRT warranty claims. I have blown up engines and successfully had both porsche and subaru replace long blocks and short blocks in tuned cars. Porsche knew my car was tuned, subaru did not and I had no qualms about lying to them because they have knowingly sold the EJ motor with a critical flaw (well actually 3 critical flaws) that frequently lead to motors grenading, tuned or not.
My van has an OETuning tune, and I recently had some warranty work done on some emissions equipment. The first thing I told them was, dont flash my ECU, it is tuned. They still covered me under warranty.
OffroadHamster
Well-known member
Well, last night I overwrote my OE Tuning tune with the Renntech HHT. First of all, if you have a tune, make sure you flash the stock tune first or you are going to have some troubles. I went around in circles a few times before getting it sorted out.
The Renntech definitely does not have as much power as my OE Tuning tune. I probably lost close to 2 seconds to 60mph. But while area under the curve is less, the deployment of the power is supremely better. Boost comes on much smoother and in a much more linear fashion, versus the stepwise fashion of the stock tune and the steep second order curve of the OE tune. Power and torque at low RPMs is significantly improved. Shift logic is improved, kick down happens sooner and more naturally, holds gears more intuitively.
I back my van into my RV storage on the side of my house, but first I must go over a tallish curb. I typically back the van against the curb and then roll up it. With the stock tune I had to get a rolling start in 2wd. If I backed it up and then stopped with the tires touching I could mat the throttle and sometimes it would not build enough boost to crawl up. With the OE tune, it would ramp up and sometimes get some boost surge followed by the bypass valve fluttering but would climb it. With the Renntech it just rolled right up from a stop. No F's given. The torque hits WAY earlier in the RPM band with the renntech and it is easy to meter it out.
I used to drop the van into 4 low just to make it smooth getting over the curb into my side yard. This is not required with the Renntech. Which leads me to this; the van will by IMMEASURABLY more capable off-road. The torque arriving earlier in the RPM band will pay huge dividends for picking your way over obstacles and maintaining momentum in the van, as well as restarting when momentum is lost. This is probably going to be the single most significant upgrade in terms of off-road capability of the van.
Lastly, I bought the black Friday speed bundle from Owl Vans which includes the power pedal. Ill be selling it. The throttle mapping of the Renntech is smooth, predictable and well metered. Once again Renntech has proven themselves Master Benz Tuners. Great product.
EVERYONE with a 6cyl sprinter that has any aims of tackling the road less traveled or whose van is punching above its GVWR should not consider this optional, but required. My Van is a whole new animal and drives the way i've always thought it should.
The Renntech definitely does not have as much power as my OE Tuning tune. I probably lost close to 2 seconds to 60mph. But while area under the curve is less, the deployment of the power is supremely better. Boost comes on much smoother and in a much more linear fashion, versus the stepwise fashion of the stock tune and the steep second order curve of the OE tune. Power and torque at low RPMs is significantly improved. Shift logic is improved, kick down happens sooner and more naturally, holds gears more intuitively.
I back my van into my RV storage on the side of my house, but first I must go over a tallish curb. I typically back the van against the curb and then roll up it. With the stock tune I had to get a rolling start in 2wd. If I backed it up and then stopped with the tires touching I could mat the throttle and sometimes it would not build enough boost to crawl up. With the OE tune, it would ramp up and sometimes get some boost surge followed by the bypass valve fluttering but would climb it. With the Renntech it just rolled right up from a stop. No F's given. The torque hits WAY earlier in the RPM band with the renntech and it is easy to meter it out.
I used to drop the van into 4 low just to make it smooth getting over the curb into my side yard. This is not required with the Renntech. Which leads me to this; the van will by IMMEASURABLY more capable off-road. The torque arriving earlier in the RPM band will pay huge dividends for picking your way over obstacles and maintaining momentum in the van, as well as restarting when momentum is lost. This is probably going to be the single most significant upgrade in terms of off-road capability of the van.
Lastly, I bought the black Friday speed bundle from Owl Vans which includes the power pedal. Ill be selling it. The throttle mapping of the Renntech is smooth, predictable and well metered. Once again Renntech has proven themselves Master Benz Tuners. Great product.
EVERYONE with a 6cyl sprinter that has any aims of tackling the road less traveled or whose van is punching above its GVWR should not consider this optional, but required. My Van is a whole new animal and drives the way i've always thought it should.
Christian-
Active member
This is a great review, but since the original thread is specifically pertaining to the warranty and some folks are worried about Renntech and warranty compatibilities - I don't think it's fair to call this "required".
I had my van in to Littleton MB (in Colorado) the other day, and they had a very large poster advertising Renntech tuning. I asked my Service Advisor if they installed the tune on Sprinters, because the poster only showed other MB models for the Renntech tune. He said "Yes, we do. It will not affect your warranty, but we will note in your service record that your vehicle has had this installed. That's needed in case any future maintenance is required."This is a great review, but since the original thread is specifically pertaining to the warranty and some folks are worried about Renntech and warranty compatibilities - I don't think it's fair to call this "required".
He quoted the cost at $1,600 with a 7 to 10 day lead time. That price is quite steep, but it seems that MB will both install the Renntech tune and support it without violating the warranty.
OffroadHamster
Well-known member
I think it is fair. Ive already stated that I've successfully had warranty work done while explicitly telling the dealership "dont flash the ECU, its tuned". With the Renntech you can flash to stock before taking it in.
I've always thought of tuning while under warranty like this: Any particular vehicle has the potential to have a manufacturing defect, weak point etc. If you tune the vehicle, you increase the likelihood of eliciting a failure earlier in the vehicles life. If the vehicle is under warranty, you have some chance of getting it repaired under warranty, if you wait until a vehicle is out of warranty to tune it and said weak point rears its head, you have ZERO chance of getting it repaired under warranty.
I get that everyone has their own level of risk aversion. In my experience tuning cars, a well sorted tune will not cause a failure
I've always thought of tuning while under warranty like this: Any particular vehicle has the potential to have a manufacturing defect, weak point etc. If you tune the vehicle, you increase the likelihood of eliciting a failure earlier in the vehicles life. If the vehicle is under warranty, you have some chance of getting it repaired under warranty, if you wait until a vehicle is out of warranty to tune it and said weak point rears its head, you have ZERO chance of getting it repaired under warranty.
I get that everyone has their own level of risk aversion. In my experience tuning cars, a well sorted tune will not cause a failure
That is going to be a dealership by dealership deal. There are Audi dealers who install and support Stasis and will honor warranty work, while others will try to turn your claims down. However, if you know the ropes, you can compel even the latter to honor warranty claims on a tuned vehicle.
avanti
2022 Ford Transit 3500
No. It seems that one dealer will install the Renntech tune and claim to support it. Your service advisor does not speak for MB.
Get it in writing (and good luck with that).
Renntech does indeed appear to have EPA (or at least CARB) certification for at least one MB vehicle. Their website proudly says:
I have no reason to doubt this, but such certification has to be done on every specific vehicle configuration. I can find no evidence that such certification exists for any Sprinter. You can judge for yourself whether this confusion is deliberate on Renntech's part. I very much doubt that the missing Sprinter on your dealer's poster is accidental.
avanti
2022 Ford Transit 3500
Not if the tune violates the Clean Air Act you can't. That's why the EPA certification for your specific vehicle is important.
OffroadHamster
Well-known member
If your dealership will support, thats good enough. The information they supply to mother benz is at their discretion. If the service department determines a failure was "not due to the tune" then that is sufficient. Magnussen Moss governs here and the service department can elect to deny a warranty claim provided they can demonstrate that the failure was due to the tune, which is all but impossible. Its much easier for them to sell a product, make some money, and then get you back in for service at their dealership because you know they will honor your warranty. Its a win win win for them.
Want to bet??? Ive got several grenaded short blocks sitting in my garage that were replaced under warranty.
Here in CA we have the strictest smog laws in the country. I live in a smog county. My van passed smog with an OETuning tune on it. I fully expect it to pass with the Renntech.
And warranty claims have NOTHING to due with the clean air act. A warranty is a contract between you, the consumer, and the manufacturer. What they decided to do or not do inside of that contract is up to them, not the government. Your response is nonsensical. (edit: I dont mean this in an inflammatory way, just that A does not follow B in my opinion)
And And, yes you can, and I have multiple times over a couple decades. I have empirical evidence, you have conjecture. So think what you want and Ill know what I do.
Look folks, if you are too afraid to tune a vehicle because of warranty, then dont tune it. If it does not concern you, then do it. Simple.
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OffroadHamster
Well-known member
Avanti - I get that your presumption (I think anyway, correct me if I am wrong) is that a tuned vehicle pollutes more than an untuned one and that, because of this, by tuning a vehicle you are violating the law. I also get that you have drawn some kind of connection between the presumption of violating the law, and a manufacturers new vehicle warranty.
Unfortunately for your argument as I understand it, no such connection exists between the CAA and a vehicle warranty.
Also, I think that your presumption that tuning causes more pollution is not universally substantiated. While tuning a vehicle may violate the clean air act, it does not explicitly mean a tuned vehicle pollutes more than an untuned one, which is, I think, the basis of your point here? Correct me if I have misread you here.
To be clear, I don't think an individual tuning a personal vehicle violates the letter of the law as I understand it. Neither the CAA or its subsequent amendments addresses what an individual does to their car so long as it meets the jurisdictional requirements for SMOG and safety. What it does address is what manufacturers and aftermarket equipment manufactures can do. However I will agree that tuning a vehicle may/does violate the intent of the law.
HOWEVER, This is a discussion for its own thread and you know that! So Instead of having this thread locked because of off topic arguing, how about we create another thread "Tuning: Legal or Illegal and associated Ethics" before Orion and Grand Tour finds this thread and it gets locked like the last one which until it blew up was an interesting exploration of tuning, energy use, electric vehicles and associated topics.
The thread for anyone wanting some more research on the topic.
sprinter-source.com
Unfortunately for your argument as I understand it, no such connection exists between the CAA and a vehicle warranty.
Also, I think that your presumption that tuning causes more pollution is not universally substantiated. While tuning a vehicle may violate the clean air act, it does not explicitly mean a tuned vehicle pollutes more than an untuned one, which is, I think, the basis of your point here? Correct me if I have misread you here.
To be clear, I don't think an individual tuning a personal vehicle violates the letter of the law as I understand it. Neither the CAA or its subsequent amendments addresses what an individual does to their car so long as it meets the jurisdictional requirements for SMOG and safety. What it does address is what manufacturers and aftermarket equipment manufactures can do. However I will agree that tuning a vehicle may/does violate the intent of the law.
HOWEVER, This is a discussion for its own thread and you know that! So Instead of having this thread locked because of off topic arguing, how about we create another thread "Tuning: Legal or Illegal and associated Ethics" before Orion and Grand Tour finds this thread and it gets locked like the last one which until it blew up was an interesting exploration of tuning, energy use, electric vehicles and associated topics.
The thread for anyone wanting some more research on the topic.
to tune or not to tune, that is the question
A lot of guys here talk about adding a tune or other modifications to their van for various reasons. I would like to know how many have modified tunes and how modified you went when you did it. I would rather not get into an argument about if it's right or wrong to make mods, so lets try to...
avanti
2022 Ford Transit 3500
You are correct that a warranty is a contract between the OEM and the owner and that it may or may not explicitly exclude vehicles that violate the CAA. This is a matter of contract, not of tort law. You are also correct that Magnussen Moss forbids a warranty from forbidding aftermarket modifications. I never said otherwise.
However, all of this is irrelevant, because the CAA requires mechanics to bring vehicles that have been tampered with back to its original configuration, during any service involving the emissions system:
(emphasis added)
Therefore, emissions repairs on tampered vehicles in illegal under EPA. The warranty (and thus MM) is irrelevant.
This is incorrect. The CAA is very clear that tampering by ANYONE is a violation. This is true even if the tampering makes the vehicle cleaner.
Air Enforcement | US EPA
Information about enforcement of the clean air act. Covers mobile and stationary sources, as well as compliance monitoring and assurance.
www.epa.gov
There is no ambiguity that "anyone" includes the owner.