507 HP+ Alfa Romeo 155 Q4 

Italian cars are always mentioned with big respect. From DTM racing rings here comes legendary Alfa Romeo 155. Then another Italian legend Lancia Delta integrale was fighting on rally tracks Alfa was eating fast asphalt corners.

As we seek for serious performance we don’t deal with just Alfa 155 – we are interested in Alfa 155 Q4. Extra mark “Q4” means that this car has big balls and can easily kick your ass. 2 liter turbocharged engine and 4WD transmission were cloned from rally legend Lancia Delta integrale. Practically stock Q4 is not very fun, because car is quite heavy and engine pushes only ~190 HP.

If you are interested in very low 11 second (1/4 mile) Alfa 155 Q4 read on. To run less then 12 seconds in ¼ mile you need some serious modifications. Ok, so that’s happened to this “red bullet” Alfa?

Let’s start from the engine. People having some experience in Italian cars noticed, that newer ignition systems are too complicated for easy tuning, so Q4 was equipped with electronics from Lancia Delta integrale EVO ( ECU, wires, distributor and etc.). ECU was already chipped with EVO Cars chip. The bottom end of the engine was balanced and only stock pistons were replaced with forged pistons. This is high boost engine so stock head gasket was replaced with metal Spesso A group gasket also 12 mm bolts were used to tighten head. A Group camshafts with a higher lift enables 2 liter engine to rev over 7200 rpm limit. It is possible to rev engine over 8000 rpm mark, but it’s required good forged pistons, perfect con rods and programmable engine management system.

Italian fans know that stock exhaust manifold is very bad and upgrading it to equal length manifold can increase engine power by almost 20%. Also upgraded manifold gives quicker turbo spool up and better low end performance. “Holzer” exhaust manifold gives extra low end power needed for perfect launch.

Stock Garrett T3 turbo was replaced with bigger Garrett T3/T4 hybrid turbocharger. Huge down pipe and 76 mm racing exhaust system was fitted. Then we talk about high boost we don’t think that plastic intercooler (stock option) will ever hold 2 bar boost. If you don’t believe me try to pump 2 bars and you’ll see how it explodes. So this plastic stuff was thrown out to the trash box and slightly modified Lancia Delta integrale intercooler was installed.

Usual Italian 4WD problem is clutch, so “Helix Autosport” metal ceramic clutch kit was ordered. It does its job very well. These options empower this 2 liter engine to produce over 350 HP, but wait – here comes nitrous!

Two stage nitrous increases power level to 507 HP @ 7000 rpm. Then nitrous is activated boost level increases so it’s always possible to blow turbo hoses or other weaker parts. Hose stuff was solved by SAMCOsport silicon hoses.