Dave A
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Registered: 10th Dec 03
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after lots of testing this are the final results to show the real difference between a 4-1 and 4-2-1 manifold. the Black line is the 4-2-1 item, as you can see its slightly better in the 2400-3000 rpm range and in the 5200-6600 rpm range it is slightly better but the 4-1 is a smoother graph and gives power for an extra 2-300 rpm later in the rev range.
different engines will respond differently but goes to show that there isnt as much difference as you might think!
Dave
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Iain M
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Registered: 18th Aug 05
Location: Wigan - Drives 272bhp corsa ZLET
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so which would you reccomend for the money
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gianluigi
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Registered: 9th Mar 05
Location: Ipswich, Suffolk
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good test there dave
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Dave A
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quote: Originally posted by Iain M
so which would you reccomend for the money
id happily have either. one of the manifolds in that graph is £180 and the other is £500+
make your own mind up
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Dave A
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also bear in mind that on different spec engines you will get completely different results.
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Iain M
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Registered: 18th Aug 05
Location: Wigan - Drives 272bhp corsa ZLET
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How come thou the price is so far apart and yet performance isn't?
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Jenko_Sport
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Registered: 25th May 06
Location: Stoke-on-Trent
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Which monifolds have you tested just out of interest?
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Paul_J
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Registered: 6th Jun 02
Location: London
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did u remap the engine after changing each manifold?
would this matter?
so if I whacked a 4-1 mani on my car (which already is mapped with cams and with a 4-2-1) would it be ok, or would it ruin the map...
my mate had a gti with the 4-1 and it pulled hard to 7800 rpm, mine with 4-2-1 pulls hard to 7200 and then runs out of steam a bit... been tempted by 4-1 for years.
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Vaux Lad
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Registered: 15th Dec 04
Location: Stoke-on-Trent
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quote: Originally posted by Iain M
How come thou the price is so far apart and yet performance isn't?
Depends who sells them tbh.
For example, say Sportex sold one for £150, and Sbd sold the exact same type, youd expect SBD to charge more, just due to there name etc.
Ideally the map will need a tweak when changing a manifold, as its changing the breathing characteristics.
Dave-Was that a protec 4-1?
[Edited on 11-10-2007 by Vaux Lad]
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Lee Wilson
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Registered: 20th Feb 06
Location: Fareham, Hants Drives: XE Corsa
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I'd definatly go for the cheaper one
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Iain M
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Registered: 18th Aug 05
Location: Wigan - Drives 272bhp corsa ZLET
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I'd have the cheaper one. Especially if its made exactly the same. Basically your paying for the name.
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Vaux Lad
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quote: Originally posted by Iain M
I'd have the cheaper one. Especially if its made exactly the same. Basically your paying for the name.
That was just an example i made up,lol.
SBD manifolds are indeed top quality/well designed.
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ed
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Registered: 10th Sep 03
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Hardly. You couldn't justify that much extra if they are 'made the same'.
Did you measure torque too? That's where the differences lie between the two options.
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Rhino
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Registered: 18th Oct 03
Location: Falkirk
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Good test, not as big a differance as a thought there would be.
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Jenko_Sport
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Registered: 25th May 06
Location: Stoke-on-Trent
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Well looking at that graph theres about 5bhp difference.
Wouldnt mind seeing the torque fingures aswell and see the curve.
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gavin18787
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Registered: 22nd Feb 05
Location: Basildon, Essex
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Which price relates to which?
Would be nice to see the torque and a comparison to a standard item too
Drives supercharged Tec with torque
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Dave A
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wasnt enough difference in the torque graph to see, wasnt worth printing it out.
The map was adjusted for both manifolds accordingly but the only difference was the rev limit really. once the cylinder has ignited theres not much you can adjust on a map to make a big difference in the map exhaust wise.
Paul_J : we have found on many occasions that your engine works far better with a 4-1 anyway, raceland ones seem to work well
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Paul_J
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Registered: 6th Jun 02
Location: London
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raceland manifolds for gti's are 4-2-1 I know as I've got one.
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Vaux Lad
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Location: Stoke-on-Trent
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Paul_J-
Out of interest, whats the engine spec on your GTi?
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Paul_J
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Registered: 6th Jun 02
Location: London
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106 gti
Kent Pt 51 cams
Chipwizards ECU remap
4-2-1 Mani
Pugsport Group N Decat Exhaust
Eccose enclosed with green filter
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Dave A
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sorry paul, typed that wrong. meant to say 4-2-1 see better gains and that Raceland ones are 4-2-1. which you already know
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SwN
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Registered: 12th Mar 01
Location: Torbay
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my old gti with pugsport and raceland enclosed filter and manifold pulled really well for a 1.6 engine , just once you got to 120(on private test track ) it ran out of steam , if i still had it i would have went the same route as you paul cams and remap
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Robin
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Registered: 7th Jan 04
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So, if the rev limiter hadn't been raised, there would be no difference in peak power at all, but the 4-2-1 is better low down, and presumably cheaper? (unless it was Protec vs SBD )
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Dave A
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a suprisingly precise guess there robin. everything you said was correct
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