Hello all - I've been a Corvette Forum member for years and have owned four Corvettes now. I just wanted to share my experience with a shop that I believe others should be aware of, as I feel that their poor workmanship put me and my family in danger and resulted in my car experiencing a catastrophic failure.


Short version: I brought a C5Z to Horsepower Addicts in Delaware to tune a newly installed twin turbo kit, install a new clutch, a brand new meth kit, and to look over the car. They did all of those things, but upon leaving the shop, over the next 5 or so drives (most of them short), I went through about 5 gallons of methanol without driving the car very hard, as it was cold outside and I was on street tires.


It was my first time having a meth kit installed on a car, but that amount seemed high to me. As I was getting ready to go for a drive, I popped the hood and found the reason why I had to keep refilling the meth – a spraying, spurting hose, spraying methanol all over my engine bay – at idle.


Link to video:

To keep this version short, they fixed the very dangerous issue, but did not fully fix the meth system, as within a few weeks, it failed to spray fully, spiking AFRs to 12.3-13.0+ and caused a catastrophic failure of the engine.




Longer version: A close friend and I brought a C5Z to Horsepower Addicts in Delaware. The car was his, but I had recently purchased it from him. When we dropped it off to HPA together, we explained that he would likely buy the car back eventually, so I wanted him to have a say in the build.


The car had recently had a c6 twin turbo kit retrofitted to it, but it needed a few supporting mods and tuning, specifically a clutch that could hold the power and a meth kit to keep the setup safe. I also asked HPA to look the car over for any other issues, because I wanted to pick up a car that was ready to go with no issues.


Once HPA looked the car over, they found a few other things to fix and recommended rerouting some wires and other lines, and other minor things, which we asked them to go ahead and fix.


It took a couple months to get the car back, but there were communication issues, so no big deal. I was excited to get her back.


When the car was being delivered, I observed that there was a strange electrical issue, where the dash and tail lights would blink when the car was locked or unlocked, but it mostly seemed to go away when driving it. This was a new issue, but I figured – “eh, it’s an older car – whatever,” having come from a C7Z and trying to keep my expectations in check.


On the drive home (2.5 hours or so), I didn’t experience many issues – it was cold outside and the car made a lot of power (cammed, twin turbo) and I was on street tires, so I couldn’t really gun it much. Over the next few weeks, I drove it 4-5 times, but wasn’t really able to drive it very hard until I put some stickier tires on it. Strangely, over those few drives, I went through a full 5 gallon jug of methanol, which to me, seemed excessive, but I wasn’t sure what to expect, as it was my first car with meth injection.


One nice day, I went to go drive it and had started it, but before I drove off, I popped the hood and was shocked at what I saw – methanol spurting all over my engine bay. I thought “Holy shit… this stuff is extremely flammable and spurting all over, no wonder why I went through 5 gallons in like 5 drives – it’s been spraying all over my engine bay!!”


I thought a hose must have burst. I thought “well, I probably don’t need to take it three hours back to HPA to replace a busted hose, I’ll take it down the road to a trusted performance shop to replace this hose,” and at the time, was just happy I caught it and that it didn’t burn the car down or hurt me or my family.


As the rest of the meth spurted out, emptying the reservoir, I drove it to the local shop and the tuner was able to take a look. We put a little more meth in the reservoir so he could observe what was happening. What he quickly realized was that the hose didn’t burst – it was just that it was only hand-tightened by the shop who installed the kit, Horsepower Addicts. Not only that, they saw that it was spraying at idle – not the way it is supposed to work.


When he tightened the hose – meth was now spraying into the engine at idle, making it run so rich that I basically couldn’t drive the car away without it wanting to stall.


That is when I decided that it needed to go back to HPA for them to fix the issue. The local tuner spoke with HPA on the phone and they instructed him of how to temporarily turn off the meth so that I could limp the car to Delaware.


Once the car got to HPA, they diagnosed the issue and found that the kit was likely not grounded well enough, causing the issues with the meth spraying when it shouldn’t.


Unfortunately, without the hose being tight, when meth was spraying, it wasn’t spraying into the engine where it should have been, but into the engine bay – so among those first 5-6 drives, it’s likely that the engine was already being put in danger. The car was a little harder to start, but I didn’t think anything of it – blaming it on being an older car.


So I picked the car up and it seemed to be running really well. It made great power and the meth seemed to be working correctly; it was set up progressively – one light would go on signaling that it was starting to spray, and the light would change color when the system was spraying fully. I believe that it worked for a week or two, but within weeks, I noticed that the car started to pop quite a bit when decelerating, which it hadn’t really done before. It was odd. Along with that, the car started to get really hard to start – taking 10 seconds or so of turning over, and pumping the gas, trying to get it to start.


So with those symptoms, I took it on the highway to try to see if everything was working correctly, so I went into boost and watched my gauge. The AFR seemed really high, around 12.3-13+, but I also noticed that the meth light wasn’t changing color; the meth wasn’t spraying fully. I got the car home and emailed the shop, explaining the popping upon deceleration, the increased difficulty in starting the car, and what I noticed about the meth light and AFRs. Over the period of a few weeks, it was difficult to get a response from HPA, sometimes a week or more between the responses, mostly defensive emails. I went on a work trip for a week and came back, tried to start the car, and it wouldn’t start. I guess once all the parts had a chance to cool down, it no longer had any compression.


I reached back out to HPA with an update, and got more defensive replies, insinuating that my car was junk and built with junk parts (the meth kit was brand new, purchased by HPA). I have lost faith in this shop and won’t be returning, and I’ll be sharing my story with as many people as want to read it.


The car will be going to another shop for full diagnosis.


Heed the warning – that could have been meth in your engine bay, when you were driving with your family, risking lives and the car that you probably worked very hard to purchase and modify.


I’m happy to answer any questions that anyone has.