antnicuk

I have recently had my new Series 5 Turbo II engine mapped on the dyno and hit 350 rwhp at 14 psi, it made the 350 at 5500 rpm but the bhp line then goes flat and starts to tail off just above 7k rpm even though the boost holds strong and stable all the way to 7500 rpm. The exhaust is 3.5 inch straight through, the inlet pipes are all 3 inch with an FD Upper inlet manifold.

The tuners think it maybe that the intercooler is causing a restriction and would show up with a pressure test each side of it.

What is an acceptable level of pressure drop?

antnicuk

here is my graph,

there are 3 runs

the top run which is pink is a year old, it was my old engine with low comp rotors and a GT35/40, 0.96 turbine housing small street port,

The middle run which is red is my new engine with FD rotorsand the FC UIM with a large street port (huge) same turbo but with a 1.15 exhaust housing both T4 flange.

The black run is with the FD UIM on the new engine.

The old run may have been a slightly higher boost but the two new engine runs are a touch under 1 bar, about 13.5 - 14 psi.

I now need to try and figure out why both engines hit 350 bhp and stop, although the new engine makes it a lot earlier. The graphs are very similar considering the porting is much different and the turbine housing is different and the rotors are different. (its actually a completely different block)

I have plenty fueling, only hitting 74% duty cycle.

The only thing that is the same is the intercooler whic the tuner thinks maybe restrictive.

What do you think?



BHP and torque, both rear wheel figures.

antnicuk

FYI, i checked the pressure drop on my i/c and i had 3 - 4 psi more on the turbo side that at the plenum. too much>???????

The engine is most definately ported, i built it, i will attach some pictures of the ports.


Here is the i/c i use, XS power


Ported LIM which the old engine didnt have as the port runners were stock.



2ndaries



exhaust


the primaries are also huge with much bugger runners