SAL
Premium Member
Registered: 19th Dec 05
Location: Radlett, Hertfordshire
User status: Offline
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ok so i got 121bhp last time on the rollers 
since then i have had the middle box put back in as there was no back pressure at all
im looking to fit a lightened fly this month, then a manifold next month, the following month will be a re-map
whats the guess ? im hopeing for at least 140 or am i being to optermistic
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AK
Member
Registered: 5th Jul 00
Location: Aberdeen City
User status: Offline
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mistic meg...
130.
dont know your full spec. Inlet?
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Scotty C
Member
Registered: 6th Nov 05
Location: Kidderminster Drives: 1.6 16v Sport
User status: Offline
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Yeh he's got a inlet, wont hit 140bhp. Add some cams, veriners & headwork and you're there.
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SAL
Premium Member
Registered: 19th Dec 05
Location: Radlett, Hertfordshire
User status: Offline
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lexmaul inlet  nothing else and i got 121 before getting my back pressure back 
will be using jamsport for the map (most probs)
and using a lexmaul manifold
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Robin
Premium Member
Registered: 7th Jan 04
Location: Northants Drives: Clio 182 Cup
User status: Offline
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Without a ported head, it'll be the same spec as mine was basically, I had 130bhp.
Ported head will get you another 8/9.
130 ish is more likely than 140.
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Robin
Premium Member
Registered: 7th Jan 04
Location: Northants Drives: Clio 182 Cup
User status: Offline
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My spec was -
Lexmaul
Viper
Janspeed manifold
decat
BFO system
Jamsport Map
130bhp, 123 lb/ft
Broster had an expensive ported head on top of that and made 139bhp, 124 lb/ft
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SAL
Premium Member
Registered: 19th Dec 05
Location: Radlett, Hertfordshire
User status: Offline
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 alot of money for not alot of power increase 
umm
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Robin
Premium Member
Registered: 7th Jan 04
Location: Northants Drives: Clio 182 Cup
User status: Offline
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The remap totally transforms the way the car drives.
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Scotty C
Member
Registered: 6th Nov 05
Location: Kidderminster Drives: 1.6 16v Sport
User status: Offline
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quote:
Originally posted by Robin
My spec was -
Lexmaul
Viper
Janspeed manifold
decat
BFO system
Jamsport Map
130bhp, 123 lb/ft
Broster had an expensive ported head on top of that and made 139bhp, 124 lb/ft
Going by that im not going to hit 150bhp then. Just headwork, lightened flywheel, cams, & verniers on top of your spec
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Robin
Premium Member
Registered: 7th Jan 04
Location: Northants Drives: Clio 182 Cup
User status: Offline
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With a Gary head, no. Mark's head was a £500 one, fully flow tested and everything enlarged as much as it could be.
Some engines are stronger than others though, so you never know.
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Scotty C
Member
Registered: 6th Nov 05
Location: Kidderminster Drives: 1.6 16v Sport
User status: Offline
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Damn
Sorry to hi-jack Stavs 
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Vaux Lad
Member
Registered: 15th Dec 04
Location: Stoke-on-Trent
User status: Offline
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quote:
Originally posted by Stavs
since then i have had the middle box put back in as there was no back pressure at all
The exhaust manifold/downpipe develop the majority of back pressure.
Middle box doesn't do a lot, as its a straight through design.
On a few engine conversions i've drove the car with no exhaust system, just downpipe/manifold and its drove pretty much as normal, just a bit louder,lol.
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Dave A
USER UNDER INVESTIGATION - DO NOT TRADE
Registered: 10th Dec 03
Location: County Durham
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copy and pasted from another thread I posted on about backpressure:
exhaust design is a lot more complicated than people realise. most off the shelf exhausts are more for the look and sound rather than perfomance really.
what some people term as 'backpressure' does exist but its not strictly backpressure as such. Making an exhaust that is well designed isnt easy, to do it properly everything from inlet design, cylinder pressure, valve overlap values need to be taken into account (sometimes refered to as 'pulse tuning' )
the Idea behind 'backpressure' is this: as exhaust gasses exit the combustion cylinder into the exhaust posrt and into the manifold they are at a high speed. once the exhaust valve closes the gasses create a virtual vaccum behind them, this helps to suck the next load of waste gasses out and so on... if the exhaust bore is too big or too free flowing or the primaries of the manifold are too short or long then the amount of pressure pulling the next lot of waste gasses out of that cylinder is reduced therefore the gasses escape slower and the speed of the engine is reduced and the inlet gasses enter slower and so on....
there is a lot more to exhaust design than you might think......
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SAL
Premium Member
Registered: 19th Dec 05
Location: Radlett, Hertfordshire
User status: Offline
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thanks for the info dave 
monster this is good info for both of us
so tbh i would be best to find some form of 2.0 and start with more power and build up...
im thinking xev power if any  XEV 
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Scotty C
Member
Registered: 6th Nov 05
Location: Kidderminster Drives: 1.6 16v Sport
User status: Offline
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I'm running and de-cat and no middle box, mine seems fine on the road. And is not lacking power what so ever.
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Robin
Premium Member
Registered: 7th Jan 04
Location: Northants Drives: Clio 182 Cup
User status: Offline
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It would be better with a centre box, get a rolling road graph and you'll see your torque curve looks like a mountain range, not a nice smooth curve.
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Robin
Premium Member
Registered: 7th Jan 04
Location: Northants Drives: Clio 182 Cup
User status: Offline
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Although, that said, mine might have been like that as it was a 1.4 using a 1.6 ECU with a map for a modified 1.6, so it was probably overfuelling a lot
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Dean_W
Member
Registered: 13th Dec 05
Location: Downham Market, Norfolk
User status: Offline
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My spec is: -
Mantzel
Ported head
Courtenay cams
Janspeed fannymold
De-Cat
No re-map though. It made 132 on the rollers.
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Warren G
Member
Registered: 14th May 06
Location: Kent
User status: Offline
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prob just under 130bhp
flywheel makes no difference to bhp but alot to performance
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