No I'm not saying it's operator error as in Dropptop is actually doing something wrong. Remember the VR38 runs at 480-600hp(nismo), and they have a 5yr 60K mile powertrain warranty. But if you launch the car excessively or if they can show excessive abuse they can void your warranty. Even at that point there are warranty issues because nobody is perfect, from assembly, to suppliers of pars, etc.
The failure mode was bearing wear, but why is unclear. Is it due to oil dilution from E85 and thus lower viscocity? Was the torque too high causing flexing and the crank journal making metal to bearing contact? Was the girdle flexing? I'll get pics later today but the girdle was flexing, the cast iron main caps where separating pretty badly from the AL casting around it. We see that typically when an engine is making lots of torque. Was it bad bearings? probably not, no bearing in the world will last if the mains contact the bearing surface under significant load. The oil film prevents that. But if the oil viscocity is compromised, or the block flex lets the crank journal touch a bearing surface....
As far as spec'ing the components, we use a factory block and factory girdle. The crank is Bryant racing crankshaft, the same as other competitors use. Also if bearing clearances aren't right, it shows up pretty darn quick, like in the break in period or first uses under load. We build well over 100 engine per year and with our process documentation and built in checks there are virtually zero assembly errors.
Just because it's a built engine doesn't mean it will hold up to X amount of HP for 24K+ miles. We're still working with many OEM parts. If you look at HP per displacement you can see that big HP OEM cars have pretty large engines, they do this because you can't change physics! An 8.0L buggati Grand sport Vitesse makes 1184hp, that's 148hp per liter.. A stock GTR makes 126 to 157 hp per liter. See the similarities? A Mclaren 720S , which is very technologically advanced, costs over $300k, , and has a 3 yr, warranty, makes 177hp/L. Let's even take a basic Alpha9, which is about 1050hp at the crank on E85, we're at 276hp/L on a block/girdle that was designed for 157max on their NISMO! that's 75% more power. But really we should be looking at Torque, because that is what causes cylinder pressure and stress on components. So a 2018 NISMO makes 481 ft-lbs. or 126 ft/lbs per liter. A std. GTR makes 467 ft-lbs, only 14ft-lbs less than a NISMO, why? An alpha 9 on E85 typically makes over 1000 ft-lbs of torque. So now we're 263 ft-lbs/L, which is 108% or more than double over a stock NISMO. So we have a factory block that is designed to handle 467ft-lbs - 481 ft-lbs now handling over 1000ft-lbs. We're not miracle workers over here, the foundation of the engine is still stock Nissan, hence why we made a billet block for the really high HP/TQ stuff.
This is the path of modifying a vehicle, there are risks with using OEM parts and also pushing high output/torque per liter. If we were building engines 3.8-4.0L V6's to handle 1500hp and 1000 ft-lbs of torque with 24K mile warranty, what do you think that would cost? Engineering from ground up?
here is a race engine used in the current Indy Light series from AER, which are high end engines.. https://www.aerltd.c...nes/project-63/
a 2.0L 4 cylinder making 368 ft-lbs turbocharged. no maintenance for a full season. - 184 ft-lb/L, not much more than the stock engines we looked at above! And these engines are specifically engineered from the ground up for that power and torque and they are big $$!
Sorry for the long post, I just wanted to give some perspective on modifying the VR38 in general and the assumption of them being 'bulletproof' if you build them. Most of the time it works out great, but there is no guarantee. We've built and tuned plenty of Ronin package GTR, which are 4.1L strokers and Alpha 9, never had one issue with them that we built here. One particular customer comes to mind, we built him a Ronin package in early 2014 and he runs flex fuel, races the car and drives it, still running strong to this day.
Any questions I'd be happy to answer to them.
So, you’re saying the common variable is the customer and therefore it’s operator error? Are there any other common variables?
Not disagreeing with what you’re saying, just shows how amazing it is that auto manufacturers can build thousands of cars that go hundreds of thousands of miles on a Daily basis. Imagine all the variables at play there. Who knows if anyone changes their oil at all during warranty, or if any cars are ever revved to the max. Amazing the manufacturers can stand behind it all.....
1500 and 3500 miles just seems quite low....do you approve that the components were properly spec’ed for the power levels produced?