1. •Stock Airbox
   

2. •EPL 85mm MAF housing
   

3. •RS4 accordion
   

4. •RS4 Y-pipe
   

5. •TiAL turbo inlets
   

6. •ER intercoolers
   

7. •APR bipipe

1. •Late model intake manifold
   

2. •72# Bosch EV14 injectors
   

3. •RS4 fuel pump
   

4. •034 phenolic spacers
   

5. •p/p stock exhaust manifolds
   

6. •ASP 3” downpipes
   

7. •Milltek Superdual exhaust

The Goal

As a member of the beta test group my intent was to evaluate the F4H turbo against the vendor’s goals, and as an S4 owner making a significant change, to assess the performance against the previously installed 605 turbo system.

The Process

The evolution to get to the point where I could make such an assessment involved initially working with VAST Performance, which proved to be a disastrous decision that was costly and time consuming and netted me nothing but aggravation and a complete disdain for the owner and management at VAST.  That whole debacle will be documented later.

I returned to a tuner I could trust and with whom I’d had prior experience, EPL.  This move proved beneficial in numerous ways, the most relevant to this analysis being that the supporting hardware on the car would be identical to what was in place during the time that the 605 turbo’s were installed.

The vehicle configuration is critical to the results obtained and it should be pointed out that the results could vary substantially from what I have observed if different components were mounted on the vehicle.  For instance, the addition of a water/methanol injection system could have altered the results, and a more significant upgrade such as aftermarket connecting rods would certainly have led to different results.

For this comparison it is important to understand the conditions I was evaluating, those were, a stock 2.7T motor with no water/methanol injection system and typical aftermarket intake and exhaust components.  These consisted of:

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