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One way to achieve more torque and power.


Titanium7

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Spent a very interesting morning at Emerald on the rolling road yeserday. Having had Dave Andrews work his magic on my K series engine I spent the morning having it mapped by the team at Emerald. The engine had throttle bodies and a BS air box with GRP 90mm trumpets for the first power runs and it struggled to get anywhere near the expected 200BHP and only made around 187BHP and 140 ft/lbs of torque.

 

Having previously been at Emerald when Dave Walker was developing the adjusable ram pipes/trumpets and had them tested on my engine we decided to try them again. (here)The results were amazing. Keeping the new ally pipes at the same 90mm as the grp originals the power and torque jumped way up and ended up after playing with the fueling at 202BHP at 7700rpm and a very healthy 156 ft/lbs at 5330rpm.

 

Needless to say the car now has the ally pipes on and a pair of twin Pipercross sock filters on permanently which has resulted in a very 'raucous' sound track 😬 and also pulls like a train.

http://thumbsnap.com/s/VtqfgxgE.jpg?0401

http://thumbsnap.com/s/6lQJ3amQ.jpg?0401

 

 

 

 

Edited by - titanium7 on 1 Apr 2014 18:37:04

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Yes I have tried with the intake and exhaust primary lengths, they tend to rock the power and torque up and down the power graph.

 

The most impressive gains I have found can come from changing the cam timing on the rollers, I have done my Duratec and a ST 170 Zetec both with good results.

 

The Zetec ST 170 I built with 12:1 comp and 45mm tbs made 185 bhp at 5900 then power dropped off, with the VVT removed and cams set at 108 deg.

 

When we had a second go we shortened the headers 100mm and the trumpets 20mm, the exhaust cam was still set at 108 deg.

 

Only retarding the inlet cam five times about 12 deg total it picked up 30+ hp.

Finished on 220hp at 7000 rpm and never lost any power or torque lower down the revs.

 

Chris.

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Tried various other lengths and it did play about with the power and torque. Dave thought the longer they were the better. We had tried 300mm 😳 in 2011 when developing them. I am sure its to do with pulses and harmonics but what do I know!

 

Just ended up as giving the most torque when set at 90mm. They said that was pretty good for a 1.8K (with a DVA K05 head)

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Quoting Dave Jackson: 
so in essence, you took the airbox off and gained power ?

 

This is what it seems to me also: 90mm with airbox off - 90mm without airbox on.

Unless there is some fatal flaw with the bell-end of what you took off?

 

What airbox or filter did you put on after the session and you do a final run with it on?

 

Peter

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Sorry, just one more question.

Did you do a run with the new trumpets before adjusting fuel?

The same power may have been available with the original trumpets had the mapping been done with them on.

Like for like / change one thing to compare.

Curious to know if the trumpets were allowing greater power to be developed.

 

Peter

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GRP trumpets were parabolic, ally pipes parallel.

All fuelling was done with the original air box and trumpets and then a straight swap with the ally tubes with the same protrusion with the air box off and the gain was spotted at that point. Varying protrusion lengths were then tested but the original 90mm proved best. Air box was then replaced with the ally tubes at 90mm and the torque figures dropped more than the power.

 

So a combination of swopping to parallel tubes and air box removal produced the increases. As Dave J says it could be down to the air box but previously in 2011 we did the same testing and the developmental tubes produced big increases in torque when set at nearly 200mm. Biggest gain this time again was in the torque figures.

 

The engine is currently set up with the parallel tubes set at 90mm with a pair of Pipercross twin socks on them.

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I love Emerald's adjustable trumpets. Something else to play with on the rollers as well as cam timing and mapping. You can see changes in the power curve with small changes in length.

 

I run a big Pipercross dome filter mounted on a flat back plate bolted to two of the trumpet adapters flipped around. One time at Emerald with my old 150bhp engine, we did a couple of final runs with and without the filter on. The difference was +1bhp with the filter, so it was basically invisible as far as the rolling road's tolerances were concerned.

 

For the record, mine are set at 130mm length, to try and pull the peak power down from piston-exploding revs and boost mid-range.

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T7, ta for the extra info. I'm always keen to know what effect comes from where.

Sounds as if the airbox was obstructing. Do you know what clearance between the bell-end and the inner surface of the box? I believe that >=1diameter proximity stops being any issue.

DJ is right that a sox is not conducive to good flow into the bell-end, hence plenum of air in a box or under a big dome being preferred.

However as any car set up has to cater for a variety of compromises, including packaging, a sock is still popular option at times.

 

Peter

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Every engine is different, so you'll need to do some experimentation. Was it not Dave Jackson who found that the BS airbox makes no difference to power? Exhaust configuration makes a big difference to pulse tuning. Like cam timing and mapping in general, the initial settings are just that. The fine tuning comes from time on the rollers to find a sweet spot for the overall package.
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