2056 EFI - what is my weakest point

[grueng]

Have a 2056 type4 in bay-bus with ms2 EFI.
It runs great, but supposed I got even more hp's from this setup.

Want to find out whats the next step to gain even more.

MS 2 EFI with wasted spark coil
stock type 4 2,0FI plenum and inlet
One modern electronic throttlebody (oversized)
European motorworks type C cam
8,5:1 compression ratio
2.0 heads ported / modified by proffessionals
39 mm inlet valve, stock exhaust valve.
Stock rockers

stock heat-boxes, vintage speed exhaust (up to 150hp) with broad-band lambda.

The map are optiomized on dyno.
Get 82hp at 4600 and 150NM at 2700 (on wheels). I suppose this is close to 100 on engine.

What is the weakest point related to hp here?
-Are the stock 2.0 FI plenum, runners and inlet large enough?
-What about the rockers?

[grueng]

Today I take a look at the intake runners on a 2,1WBX. They have much larger diameter than the runners on 2,0 Type4.
Is it possible I need larger runners when I now have 35% increased horsepower compared to stock 2,0?

[Bruce.m]

Have you got a plot of the torque from the dyno?
That might suggest if it’s a flow limitation or something else.

[raygreenwood]

As Bruce notes...could be several points of restriction.

The WBX runners are larger as are the 2.0L 914 runners. I also remember that Jake Raby noted long ago that on his 2056's ...the larger 914 runners are almost a requirement. With the larger bus plenum as compared to the 2.0 914 plenum you "may" not need to go to a larger TB. Ray

[Clatter]

Do you run the '75-'78 F-pipe type exhaust?
The '72-'74 style flow better.
I'd also try a Thunderbird/CSP/S&S header.
Even though the VST exhaust is advertised at a certain horsepower rating,
It's not an extractor exhaust with a collector, and won't provide the flow a true tuned exhaust would.

Especially in a bus, you want exhaust heat sent out the back and not stacked up into the motor.

[grueng]

Have you got a plot of the torque from the dyno?
That might suggest if it’s a flow limitation or something else.

Here is the dyno chart

[grueng]

As Bruce notes...could be several points of restriction.

The WBX runners are larger as are the 2.0L 914 runners. I also remember that Jake Raby noted long ago that on his 2056's ...the larger 914 runners are almost a requirement. With the larger bus plenum as compared to the 2.0 914 plenum you "may" not need to go to a larger TB. Ray

Do you mean the 2,0 914 runners ar larger than 2,0 bus runners?
I use 2,0 bus plenum and runners today.

[raygreenwood]

As Bruce notes...could be several points of restriction.

The WBX runners are larger as are the 2.0L 914 runners. I also remember that Jake Raby noted long ago that on his 2056's ...the larger 914 runners are almost a requirement. With the larger bus plenum as compared to the 2.0 914 plenum you "may" not need to go to a larger TB. Ray

Sorry for the delay in reply. Yes, the 914 2.0 runners are larger than 2.0 bus.

Ray

Do you mean the 2,0 914 runners ar larger than 2,0 bus runners?
I use 2,0 bus plenum and runners today.