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Target power problem


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Hi all,

I prepared a Peugeot engine 1.6 N/A TU5JP4, I have a problem on it and i need your help please.

Spec engine:

-Rod & piston hight compression Wossner

- Cr: 12.5

-Camshaft Catcams (297/286) 4.50mm/3.95mm lift at TDC

-Head porting of conduits with cnc Veicomer

-Solid lifter - Valves Springs Catcams

-Crankshaft oem

-ITBS ATPower 38mm DTH

-Exhaust manifold 4-2-1  

- injector siemens deka 400cc pressure 4.0 bar

- Ecu Vipec V44

Target power: 200bhp/190nm

Power range: 5000-8500rpm

Currently I have 177bhp/170nm (attached Dyno)

I have a problem at high rpm the power drop, I don't know why

I am blocked, I have checked all camshaft timing, sensors, current ...

Thanks advance and sorry for my english.


image 1.jpeg

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Is this graph from an engine dynamometer or chassis dynamometer?  If chassis, is it also adding the approximated losses to the reported numbers?

From your specs, the one which looks a little out of place to me is the 38mm throttles.  Im normally recommending 45mm for similar power levels - although I have no experience with the AT shaftless design so dont know how much difference that makes.   

Your torque peak is in about the right area - for an 8500RPM engine I usually see peak torque at about 65/6600Rpm, so this suggests cam timing is ok.  But the sudden drop off in torque from 7000RPM does not look normal.  My feeling is an airflow issue - maybe throttle size, exhaust primary size, tail pipe too restrictive

Have you confirmed that ignition timing follows target at high RPM?  Does it have crank/flywheel trigger wheel?


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hi Adamw,

first of all, thanks for your help and concern.

The Dyno is a BApro chassis dynamometer. The green line on the graph is the drivetrain power loss. which is 45hp at higher point on rev limiter. 177bhp - 132whp.

my first dout was the itb size, than i saw multiple known engine builder (as sandy brown) using the same DTH itbs (from ATpower) and getting +210hp.

the exhaust primary size is 42mm than 2 pipe of 51mm than a straight line 60mm

the head is a CNC ported veicomer head.

i tried to play with cam timing but the better results come from catcams recommended specs.

also the timing seems on sweet spot, for know the timing is set on point which i start losing power when i retard and not gaining power advancing.


the engine seems to struggle when its supposed to give the maximum power. the sudden drop is my problem. the car is used almost between 6K to 8.5k rpm





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