Zetec SVT/st170 engine power

[athens7]

Does anyone have a viewable dyno/rolling road chart of their SVT or st170 Zetec motor? I recently took my car to a Zetec tuner to address questions about dying when the clutch is engaged, as well as a hard starting condition. I found my motor, as provided by Caterham USA, and modified with bespoke Kent camshafts installed by my Caterham dealer, put out only 129 hp at the wheels (it was represented to me as a 200 hp at the flywheel motor). After a new PCM program, adjustable cam gears, and a vct eliminator, I got 147 hp from the motor (about the same as a stock SVT, after 15% drive train loss). There is also a hole in the torque curve between 2700-3700 rpm that no amount of cam or ignition timing adjustment seems to be able to remove. Before I throw the next wad of cash at the car, I would like to find some comparative data.

 

Brad

 

2005 SV SVT Zetec

[AMMO]

Brad

 

Look on www.dyno-plot.co.uk

 

http://www.dyno-plot.co.uk/dyno/dynoplot/id%3D327%26sort%3Drec%26but_sea%3Dqs%26sea_simple%3Dfocus/Ford-Focus-Clive-Atthowe-Rolling-Road-Tuning.htm

 

AMMO

[athens7]

Thanks-the graphs are labeled as Duratec 2000s; I thought the st170 was the same Zetec based motor as the US SVT. Also, these charts appear to be hp/torque at the flywheel. What is the consensus (if any) on a drive train loss percentage from flywheel hp to at the wheels hp?

 

Brad

 

2005 SV SVT Zetec

[CAB]

Hello Brad

I have a 2004 Focus ST170, the engine is the exactly the same as the 2.0 L SVT. It has an uprated Zetec bottom end; better con rods, pistons (I think), oil spray jets to cool the underside of the pistons, a trick cylinder head (big valves, variable intake cam timing and an adjustable lenth manifold) and a long branch (Cosworth) designed exhaust manifold. The engine is the Duratec ST in the UK and this is completely different from the later all aluminium alloy 2 and 2.3 L Duratecs. I have imported several bits from the US (adjustable cam pulley/FC throttle body/underdrive pulley/sports cat and Borla/Ford Racing exhaust). I'm afraid that the power output of these engines varies quite a bit in standard form (that could be down to the rolling road/temps etc). My car has been on two different rolling roads and the power was 165 on the first & 160 bhp on the second at the flywheel. The power at the wheels was higher on second RR at 136.7 (even with less power at the flywheel) and about 133 on the second. The first RR operator had tested several ST170s and only one made the full 170 (the Ford supplied press car funnily enough). At the time my car was standard with only about 4000 miles on it. Several experts have said that this engine needs over 10000 miles before it is fully loosened up.

129 in standard form does seem a bit low, I would expect to see slightly more from yours at the wheels, the in-line transmission should be more efficient than the transverse one fitted in the the ST. My first 1700 Supersprint X-flow 7 made about 133 at the flywheel and 100 at the wheels on the first RR above (reworked head/4-1 exhaust/ignition Type 9 5 speed box/de Dion).

The 15% that you quoted for transmission losses seems a bit low for a transverse engine, especially compared to the inline installation above in my first 7. I think it is usually quoted as nearer 30% for a transverse engine/gearbox.

Is your car fitted with the standard variable intake manifold? It sounds as if this could be stuck in the short runner (high RPM) position. I think that the manifold is in the high rpm position when the engine is stopped, switching on the ignition should switch the manifold to the long (low RPM) position. The cable to the manifold can be seen and should switch to the short position at about 5500 RPM. This could be causing your lack of torque in the low to mid range and possible affect the starting. As for cutting out with the clutch pedal depressed is the clutch dragging? Is your car fitted with the ST/SVT clutch/flywheel? The clutch in my ST was replaced at 2000 miles from new after first and reverse became hard to engage. On a flat surface the with no hand brake on the car would drive off by itself.... This was due to a faulty clutch pressure plate. I think that there is also a switch on the clutch pedal, I think that this might be for cold starting.

There are several Focus SVT dedicated Forums in the US; http://www.focaljet.com is one, http://www.svtperformance.com/forums is another. I havn't been on these sites for a while but they are usually very helpful.

I will try and dig out the plots and email them to you.

Regards

CAB

 

Edited by - CAB on 23 Oct 2007 22:13:03

 

Edited by - CAB on 23 Oct 2007 22:18:04