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dudaionescu

Supercharged Ew10 Questions

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Vili

Vili, thank you for explanations and patience. Since the charger is volumetric, the pressure is a result of the plenum chamber volume after it, so this is why I have taken pressure off the discussion. If I will place the immediately after charger then intake pressure will be the same only at WOT...

 

 

It doesn't make any difference to air density how the pressure and temp is made. Adjusting the inlet pressure at part throttle is what throttle is supposed to do and it does just that no matter if it's located before or after the charger.

You can think situation where you are accelerating in city traffic. You have car in front of you and you need say 40 motoring hp to keep up with him. Your engine produces that 40 hp at 0,6 bar absolute pressure (-0,4 bar boost) at inlet. If the pressure at inlet was 1,4 bar your engine would produce around 90 hp and you would end up hitting the car in front. So eventually you need to restrict the pressure at inlet during normal driving. And that's why in this case it doesn't matter where the throttle is during part throttle driving.

Edited by Vili

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wracing

Fitting a intercooler and having the throttle before the charger is making life very easy. you cant pump hot air into an engine and expect it to perform, you can't tune around those sort of inlet temps especially on standard compression.

 

A one way valve is a option.

 

the whole point of fitting the throttle plate before the charger is to simply control, you don't need a blow off valve/ recirculation valve to prevent flow reversion through the charger. You will get a decrease in throttle response but the benefits outweigh the gains.

 

the relationship between pressure delta and flow across a throttle body is not a simple linear relationship there isn't much point reading into it to much.

 

James

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dudaionescu

There is a bypass valve between intake manifold and pre-charger area (pic #3)...

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dudaionescu

On top of that the piggyback disconnects the supercharger clutch below 1500rpm so idle is fine.

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dudaionescu

OK gave up decompression plate and used small/stock engine pulley which yields around 0.5 bar.

Results are better than decompressed engine with 0.8 bar!

Next days a bigger billet pulley will be installed... hope a rod will not pop out to say hi through the engine block...

post-23126-0-69525500-1357768197_thumb.jpg

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dcc

much more like it!

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Dimitaar

Fingers crrossed mate :)

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dudaionescu

Guys, that's it. Clean 220HP and 280Nm at 0.8 bar peak pressure. No intercooling.

I don't want any more from it, maneuvrability now is an issue and will invest my money in handling rather than engine.

Maybe I will add an intercooler in the summer plus longer heads inlet manifold and probably will go for more HP but right now the car pulls like a beast. It's more than enough for me for city driving, much above that will become dangerous for traffic safety.

post-23126-0-43210600-1360591776_thumb.jpg

Edited by dudaionescu
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dudaionescu

Folks,

Any solid idea how to reduce cam overlap ? :(

No VVT on EW10J4...

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dudaionescu

Made it :) used the cheapo RFR vernier pulleys which allow for +/- 4 degrees advance or retard (and trust me, you don't need more). If you need to further adjust then you start making offsets by moving the belt and finetuning from pulleys...

We tried all combinations of 0, -2, -4, +2, +4 degrees advance and retard for both intake and exhaust and for this particular roots s/c setup best power was acquired with 0 degrees at intake and 2 degrees exhaust advance. About 10HP and 20Nm more on the whole powerband, Everything else was sh1te.

Lots of unburned gas was thrown off the exhaust due to NASP standard cam overlap.

A new and better investment would be custom camshafts but I'm afraid it's not worth the cost. I need bigger exhaust valves, shorter intake time due to high pressure (or at least a bigger plenum so air is not so pressurized), shorter injection time...

Edited by dudaionescu

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dudaionescu

Ok installed an intercooler, IAT is now around 20-25 celsius (80 celsius lower), no power gain even with 6 degrees spark advance. Wtf?:(

Water merg spray is now after supercharger, right before manifold. Using 3gph nozzle, no gain but 10 hp loss. Something must be really really wrong.

Edited by dudaionescu

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padula

which piggyback are you using?

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dudaionescu

Unichip Q+ but only for few tasks.

Timing curve is done by ECU maps. I am currently looking for the injector timings for this ECU. Otherwise the car runs fine, no need for stand alone management.

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