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ayup everyone' most of you know my vr is s/c

i run a standard manifold with raceland decat pipe i also had on my car standard middle box and standard suitcase box then my stainless backbox'' 2 days ago i replaced the middle and suitcase boxes with straight through stainless steel pipe work my vr now has lost loads of power and is popping, i can try to retrieve my boxes if the man still as them or buy new ones as they are as old as the car 1997'' do you need a certain amount of back pressure as it ran great before i thought it may be better or does it need a remap. sorry so long winded.

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You're right mate... your exhaust does need a certain amount of back pressure to run well. Best bet is to try and put the boxes back on if possible or at least one of them. I may be wrong though...try ringing Stealth as Vince used to deal with cup cars which actually had straight through exhausts from the engine so will be an expert on this matter.

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here' date=' have some punctuation.

,,,,,,,,,,,,,,.....................

[/quote']

Well you should be good at it,as you seem to spend all your time searching the forum looking for people's mistakes you sad person ,have you not got anything better to do on a saturday?.

This is why i dont come on this forum that often for time wasters like you.......................................... %$#^&&^%$#@!*&*((((*&^^%%%%$&&**(()*%$#@@$%&*

Can you read that Annie.

Thanks Matth76,you where right, i got it sorted on friday went back and got my middle box put back on loads better.

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A lot of us read posts like your and dont bother to reply because it takes to long to work out what your trying to say. I'M SURE you must have been taught English at school to some level.

Mk3anni ya going on as if it's in a foreign language or something,i know it looks like one big sentence but matth76 managed to read it, so what problem do you exactly have (m).

Do you teach for a living (m) by the way you missed the s of (your) in your reply to AAD :)

Dont mean to bring you into it Matth.

My point being there's no need to have a dig at people, loads of people on this site miss spell or miss letters off things they write,that just go's with the typing unless your perfect at it.

So get over it and dont lose any sleep.

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Put your hand over your mouth then attempt to breathe out through it. Hard isnt it.

Backpressure is a killer of power whether in a turbo or N/a application.

Backpressure raises exhaust temperatures through restriction, restriction is a bad thing all round for power.

Exhaust valve opens, backpressure pushes burnt gasses back into the exhaust port and contaminates the charge.

Burnt gasses dont burn, so power drops. I understand your point about drawing thru, but all that will happen there is that unburnt fuel gets into the exhaust increasing emissions and lowering economy, but theres better ways to get by that problem rather than using what is basically a restricted exhaust; restricted by backpressure that is, using a properly matched turbo for instance, correct cam and ignition timing also.

I cannot see there EVER being a NEED for backpressure of any levels being desirable as there is NEVER a rise in power on an engine when backpressure is introduced.

None is the best you can aim for, and smarter people than me would attest to it. Im sure the designers of F1 engines would agree with what ive said...(well i hope they would)

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very true... but the vr6 engine was designed with all the pressures factored into its running ability, if you mess with the enines breathing something else has to be changed to match normally, if you change a manifold on its own for an uprated one for instance that can actually be negative and cause the car to lose power if you dont change something else aswell, i would just retain a 2 or 3 box system of about 2 1/2 inch diameter and see how that goes, a standard pipe on such a modified car cant be any good for it anyway? and if everything was set up or mapped when that exhaust was fitted then that is gonna have changed loads of settings as you are expelling gasses in a different way.

ps.. is my punctuation and grammar ok? if not i am sure some "road captain" will point it out ;)

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