I have a 2006 Jetta TDI w/ 5 Speed, engine code BRM. I'm looking basically to build a very reliable vehicle that maintains its status as a daily driver while adding some power and handling to increase its "Fun Factor". I'm not looking for crazy levels of power but would like to increase the power to around 200-250hp 350-400tq while still maintaining a stock driving experience and the reliability to jump in and be able to drive across country if i want while still getting 45-50MPG+.
I see people starting to throw numbers around as a "goal" without an inkling of what it takes to get there other than maybe a few hours reading forum threads.
250 hp... That is definitely considered unusual (maybe even crazy) levels of power in a BRM. Certainly out of the ordinary, or at least would get you into the 1% club or so. Not saying it can't be done, just not as casually as you seem to want (or as inexpensively as you may have been led to expect.) You will for sure remove your car from the "just drive it" transportation category and make it your hobby. (do you have another car to drive while you spend months sorting it for that last 50 hp??)
IMO you will lose many of the things that makes your TDI such a great car, in the pursuit of peak numbers.
there are a few guys with those numbers, with giant threads with lots of gratz and thanx. But take a closer look. How many months go by, how much time and labor, shop time (paid by the hour), sorting all the little aggro things like retightening bolts every week, exhaust leaks, downtime when you can't drive the car at all, lost weekends spent with the car on jackstands and sleepless nights wrenching
At the end, hey look at the amazing dyno numbers, but that says nothing about how the car actually drives at part throttle in daily use.
Of course the peak numbers you can obtain depends on what dyno you use, and the operator. And consider that dynos only show one set of operating conditions, that do not represent the daily driving everyone does at part throttle.
Not routinely done, and not without nitrous or expensive turbos and customization, exotic headwork, complete low compression/high boost/high fuel/high smoke/ low fuel economy, and so forth. Certainly out of the ordinary and not routinely done without a lot of effort and expense. We are certainly out of the realm of a few off the shelf bolt ons and you will for sure give up SOMETHING. You are taking a 100 hp car and forcing it to produce 2.5 tines the factory output.
For example, fuel to get those numbers requires more air, which means a turbo that pushes enough to "get the numbers" which will make the car a smoky dog in the daily driver range of rpm. Because the power and torque curve is shifted to higher rpm. If you look closely at the handful of ~250 HP "alll motor" dynos that have been posted here on this site, they mostly come to life about 3000 rpm, and go to more than 5000 rpm in order to get the benefit of rpm to make the HP numbers. (Hp= torque x RPM /5252) It's not anything like driving a TDI any more. Something like driving a peaky vtec honda with an oversized turbo, that smokes a lot.
The number of BRM (or other us-market TDI) I've encountered making a bona fide 220 whp all-motor can be counted on one hand. Out of thousands of cars. 190-200 is not much of a stretch but the effort is extraordinary to get that extra 25-50 hp. And it's NOT the same car. There ARE definite tradeoffs that tend to get glossed over in the forum threads you may be reading.
After the first mod, it may seem there's always a free lunch, but there's not infinite power available. The initial dramatic gains are not infinitely scaleable forever.
Let's see what CAN be done while still keeping that TDI goodness within a reasonable budget and keep it reliable for years to come without a second thought.
Here's what you CAN reasonably expect your BRM to do in the real world without extraordinary effort. (none of this considers transmisoisn stuff like a clutch or 6 speed)
- 130 hp give or take is an ecu tune only. Low/no smoke safe operation of the stock turbo with no longevity concerns, plus improved fuel economy.
- Mild upgrade the turbo and 150-160 whp with stock injectors. This is very routine nowadays.
- The next 30-40 hp takes bigger injectors. Thisi is where the diminishing returns really make themselves known. If you want to keep the smoke and EGT reasonable with the added power, airflow mods are needed. these include camshaft, exhaust, intake plumbing. Car already has a FMIC so that's a plus. Headwork is optional but highly recommended.
Now, you CAN push the reliability of your turbo and smoke, and so on if you want to do the numbers on the cheap. You can get a tune that routinely (and unintentionally) pushes the stock turbo to 25 or 28 psi, that gets you another 10-15%, with smoke and egt. Hey, it's great for a while, but that's not what I prefer.
Maybe my take on the statement:
"I'm looking basically to build a very reliable vehicle that maintains its status as a daily driver while adding some power and handling to increase its Fun Factor."
is not the same as yours, because who knows.
You *may* be an exceptionally dedicated and talented fabricator and tinkerer like Matt Witbread who can make anything work. But for many folks a weekend spent in the garage changing a stock turbo is an exceptional event and an inconvenience. If you are a guy who lets "a mechanic" do that stuff, then get a different car if you want to say you have 250 hp.
