GolfGTIforum.co.uk
Model specific boards => Golf mk2 => Topic started by: pk2904 on 24 February 2011, 23:24
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i have just fitted 50mm manifold to my 2.0 16v ..... the conversion consists of corrado 9a engine kr kams racing four branch and wur mod and 42 mm manifolds... this made 156 bhp at stealth last month, now today i fitted the 50mm manifold on and it feels abit slower, my question is does it need to go back to stealth racing to be set up again????
cheers p
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Bigger bore = loss of back pressure = loss of BHP.
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so does that mean if i get it back at stealth it wont be as quick as before???????
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I believe the 50mm only helps torque. :undecided:
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may need setting up again, if the old one had worn injector seals and/or leaky gaskets which are now fixed. you did put new injector and insert seals on it before you fitted right?
iirc the 50mm does better for top end power, 42mm does better for low end?
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If only there was a 45mm for an in between!! Must admit, 5th gear 100mph upwards is where my abf kjet 50mm pulls the hardest.. Loadsa power available up there...
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thanks for the replies guys... yes fitted new injectors and seals etc.... little update i spoke to vince at stealth racing and he booked me in again ... he said that the 42mm are good for torque but the 50mm will produce more bhp and revvs once set up again....made me feel alot better... will keep you updated.
p
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This is the great thing about K-jet - you can spend loads of money on tuning it and it might *just* get close to what OEM Digi3 will output with a 4-branch on it. :grin:
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or you can put loads of effort into a syncro and have a car slower than a 2wd :grin:
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You have no idea and very little intellect, so maybe button it until we've been on a track together, numpty. :rolleyes:
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nah, think i'll continue to take the piss if its all the same with you, also i don't do off road events :grin:
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lads dont spam the thread please ... but if you want a proper race give me a bell........................ :evil:
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Bigger bore = loss of back pressure = loss of BHP.
Wrong, bigger bore in this case = less restriction to flow at high RPM = More power in theory. Doesnt mean you will get more torque though :wink:. Pretty sweeping statement for you to make anyway assuming you meant for the exhaust system, depends on the engine, whats been done to it and how restrictive the standard manifold is etc etc.
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Bigger bore = loss of back pressure = loss of BHP.
back pressure in an inlet manifold?????
:grin: :grin: :grin:
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Strictly speaking, yes. Back pressure is just the pressure that must be overcome in order to negate frictional losses from walls, pulse reflections and turbulence, a factor that isnt helped when you only have the atmosphere pumping the air in on the inlet side of an N/A engine. Stick a cylinder head on a flow bench and increase the port sizes noting the effect. More air in = less pressure loss or back pressure depending on how you define it though this isnt always good for torque lower in the rev range. Its a pretty major problem in intercoolers since you need to induce turbulence to encourage convective heat transfer by using internal fins which also increase heat transfer surface area inside the intercooler to further increase the heat transfer, both of which increase back pressure or the pressure drop across the system due to these factors which in turn loses you boost pressure (lower temps = more ignition advance and denser charge so a slight loss in pressure across the intercooler is acceptable as a tradeoff for more overall engine output).
Can you tell Ive just written 10,000 words on and around this subject for a Uni assignment. The poor writing is due to a complete lack of sleep :sick:, hope the assignment aint written as badly as this post!