People on this forum in the past have said that the current 150 horsepower 1.8T engine is engineered so well that it can reliably be pushed with bolt-on modifications to well over 200 horsepower. (I think some people talk about 230 and higher). The vwvortex website has plenty of good info. on the Audi TT model, including discussions of the 180 and 225 hp engines. For the 225 hp variation, they say:<p> "To permit this high performance to be achieved reliably, the 1.8-litre<br> engine has been fairly extensively modified. The pistons, connecting rods<br> and big end bearings have been uprated to accommodate the higher<br> combustion pressures. The double-mass flywheel and the clutch have also<br> been modified to match the changed performance characteristic. The<br> intake manifold, turbocharger and exhaust manifold are of entirely new<br> design.<p> The 225hp (165 kW) engine is equipped with two charge-air intercoolers,<br> through which the Type K04 turbocharger forces air into the combustion<br> chambers. The airflow path is quite different from the 180hp (132 kW)<br> version, and together with a larger air cleaner ensures that the<br> temperature of the air reaching the engine is only about 30°C higher than<br> the ambient temperature. This is equivalent to more than 80 % charge-air<br> intercooler efficiency, and keeps the engine supplied with an optimum<br> flow of oxygen-rich air. Maximum boost pressure at the intake manifold<br> can reach 2 bar."<p>So, apparently VW/Audi feels that some serious internal modifications are needed for this horsepower level (pistons, connecting rods, bearings). I just posted this for comment/info., since I was near-flamed before when I suggested that the existing 1.8T might be compromised in reliability if the horsepower were increased substantially. (Also, does anyone here know for sure if there might even be some minor internal changes between the 150 and 180 hp versions? The existing engine probably is OK at 180 horses.)

... but with some serious work. Carillo rods seem to be everyone's favorite in terms of modification, there are a couple cranks available (including a possible remachining of the 2L VW crank system that's been rumored from Neuspeed). Cosworth is always happy to make custom pistons for a price, along with a couple other people in the business. Changing displacement will help the low end, since touring cars illustrate the block can be stable at 1980cc's, a turbo swap in the right range (K24 may be a bit heavy duty, but the K04 is in the right range here) will help overall performance, and some serious exhaust work should reduce turbo problems (the main turbo problem people have been feeling will be helped by moving to a turbo without an integral wastegate...)<p>There's plenty you can do to get up there, the real question is how much are you willing to pay... the great thing about a 1.8T A4 is that you can spend $50,000 on modifications and still not exceed the cost of the next step up the line-- the Porsche 996 C4.<p>But maybe TAP and Wett are right, and anything not bolt-on is overkill... I just have trouble believing that.<p>Cameron

I replaced the RS-As on my '97 1.8TQMS with Bridgestone RE71s, $99 per tire for 225/50-16, from Tire Rack. They made an INCREDIBLE improvement in the car's handling, but they are noisier. All in all, an acceptable trade-off. I would suspect you would see a similar improvement in handling, even though you have FWD.

Dan H.
1.8TQMS

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