very simple. There are 2 reasons
- most turbo obsessed people are young, or started modding cars when they were young…and when you’re young, you’re broke…and when you’re broke, you buy a small displacement engine with a turbocharger. You also don’t have money for full exhaust and a bunch of modifications…you have a few hundred bucks MAYBE for your $3000 car. What do you buy? A tune. If you have a $3000 naturally aspirated car, a tune alone isn’t doing much. If you have a $3000 turbo car, a tune can give you 15-25% power gains. This is where the obsession comes from. This belief that turbos are best sticks in the mind of these people as they graduate to other platforms…or when they troll other platforms.
The B5 S4 is the ultimate example of this. a 2.7 litre engine that is pretty much a dud below 3000 RPM, but with a tune, it produces a violent torque slam and reasonable top end. For $400 you can add 50 hp and even more torque. Then you think you’re the bomb, and troll the other platforms (i.e. B67 S4, or B7 RS4) because you know so much. Some of the B5 guys sell their B5 and buy a B6. When they put an APR or GIAC tune on the car, and it gains 0 hp, the word spreads…NA cars can’t add hp. In that RS4 thread, guys like DaytonaRS4, badneighbourhoodRS4 et al who own NA RS4s believe this turbo thing because their RS4s gained nothing with their mods (crap tunes like EPL or no-name-joe, and poorly sized exhausts). They cling to the belief that you must turbocharge to see gains of size. This despite the fact they’ve seen superchargers do so well. Easier to join the turbo herd than think rationally. Turbos are a fool’s way to entertain those fantasies of yore.
What they don’t realise is that the NA guys get about the same gains from a good tune and well designed exhaust, or thereabouts.
- turbos, when sized nicely, can be pushed to make pretty serious power. Like insane power. Supercharging can as well, but turbos are a bit easier. People think making insane top end turbocharged power is actually fun, but its really. You’re often left with a Jekyll and Hyde powerband where it’s a turkey below 5000 RPM and a monster above it, replete with an unsettling boost spike on the engagement of boost.
The superchargers that are out there are sufficient to get 100% out of what the RS4 engine can handle . Hell some of the big boost SC RS4 kits are getting more than 100% of what the RS4 can handle, which is being reflected with the APR kit, killing cars leading to multiple engine replacements on the customer car they borrowed for testing, and a couple of others who have raised their hands on the forum. Same for AMD who showed great promise with 125MPH trap times and 500 whp on the customer car they borrowed for kit promotion, but on retail release, AMD customers have found AMD to be dialing back the power on the retail kit where we are seeing 420 whp type acceleration and dynos, not 500 as advertised for the big boost kit.
The JHM kit for example can make enough power to melt an RS4 engine. They’re not pushing their blower hard at all. The APR kit is maxing out the 1740. The AMD kit probably has some room to grow. But AMD and JHM know that there is a limit the engine can handle…so more is not necessarily needed.
THe JHM kit appears to be stuck on a stage 1 and stage 1 + intercooler offering because they feel that 9-10 psi with their kit (aka north of 500 whp) isn’t viable on a stock engine. They have developed a built motor program, and fortunately their supercharger can push that built motor to 650+ whp, so that’s a nice thing to know.
