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Author: Subject: Merge collector
ian996

posted on 28/9/15 at 10:54 PM Reply With Quote
Merge collector

Made 275bhp on the dyno today but it appears my exhaust collector is a choke point. It's a race line exhaust 4-1 so I'm surprised but it's probably down to the bodging to get my silencer to fit and it needs repacking.

So where to get a good collector from that won't cost lots of money and any ideas on design. Will a venturi type design be beneficial.


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Nickp

posted on 29/9/15 at 06:07 AM Reply With Quote
What engine / spec is it and how have you come to the conclusion that the collector is holding it back? 275bhp sounds pretty impressive especially if it's N/A
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snapper

posted on 29/9/15 at 06:11 AM Reply With Quote
I had a larger collector end welded in to the original
So count off the double step from can to collector and have a tube the same diameter as the can all the way to the collector







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ian996

posted on 29/9/15 at 06:38 AM Reply With Quote
quote:
Originally posted by Nickp
What engine / spec is it and how have you come to the conclusion that the collector is holding it back? 275bhp sounds pretty impressive especially if it's N/A


N/A Duratec

Amongst other things, main parts are:

  • Omega HC pistons
  • Saenz steel rods
  • Raceline dry sump
  • 1mm oversize Hi Port Neil Roper cylinder head
  • Kent DTEC 80 cams
  • RaceCo 54mm DTH bodies with 690cc injectors
  • Emerald K3 ECU
  • Raceline stainless 4-1 exhaust manifold and Wun-Off silencer

I think i can get slighty better port matching from bodies to head, but the tuner said the collector was a bit of a choke point.
Cam timing is spot on, rev limit is set at 9200. Might be worth recleaning the head as i when i took it for a shake down it was badly over fueling - throttle pot was reading as stuck open so was throwing huge amounts of fuel in.

[Edited on 29/9/15 by ian996]

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matt5964

posted on 29/9/15 at 06:57 AM Reply With Quote
If you have the space a 4-2-1 will free it up and improve torque figures also.

Simpson exhausts will have them off the shelf.





Luego velocity XT 2.0ltr 221.3bhp 178.9lbft

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Nickp

posted on 29/9/15 at 07:07 AM Reply With Quote
quote:
Originally posted by ian996
quote:
Originally posted by Nickp
What engine / spec is it and how have you come to the conclusion that the collector is holding it back? 275bhp sounds pretty impressive especially if it's N/A


N/A Duratec

Amongst other things, main parts are:

  • Omega HC pistons
  • Saenz steel rods
  • Raceline dry sump
  • 1mm oversize Hi Port Neil Roper cylinder head
  • Kent DTEC 80 cams
  • RaceCo 54mm DTH bodies with 690cc injectors
  • Emerald K3 ECU
  • Raceline stainless 4-1 exhaust manifold and Wun-Off silencer

I think i can get slighty better port matching from bodies to head, but the tuner said the collector was a bit of a choke point.
Cam timing is spot on, rev limit is set at 9200. Might be worth recleaning the head as i when i took it for a shake down it was badly over fueling - throttle pot was reading as stuck open so was throwing huge amounts of fuel in.

[Edited on 29/9/15 by ian996]


Wow, sounds a screamer!!

I'd do as snapper has and get a piece of pipe that matches your silencer and get that welded in place of your smaller collector outlet and see if you get an increase.

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ReMan

posted on 29/9/15 at 07:16 AM Reply With Quote
9200! Nice

It couldn't be the silencer its self choking could it? Do they have a hp/flow spec?





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ian996

posted on 29/9/15 at 08:20 AM Reply With Quote
quote:
Originally posted by ReMan
9200! Nice

It couldn't be the silencer its self choking could it? Do they have a hp/flow spec?


I know it needs repacking, it was a bit loud when i got it started for the first time, so i checked it and its something i need to do when i get back to the UK, so might be contributing. I think its a good call to sort out the pipe from collector to exhaust though, might be able to get that done for not much cash.

The power band is quite high so i think a 4-1 is better suited for this setup.

Anyone know of a good place to get merge collectors made up for reasonable money? maybe a longer flowing collector with venturi type pipe to silencer.

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mookaloid

posted on 29/9/15 at 10:33 AM Reply With Quote
quote:
Originally posted by ian996
[

Anyone know of a good place to get merge collectors made up for reasonable money? maybe a longer flowing collector with venturi type pipe to silencer.


Yes:

CGR Automotive





"That thing you're thinking - it wont be that."


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Oddified

posted on 29/9/15 at 12:47 PM Reply With Quote
If it's up at 9200rpm, your better staying with 4 into 1 collector, and as said above the collector itself looks ok but get a larger outlet pipe welded in place and then all the way to the silencer. You should be at 2.5" or larger ideally, what size is there now? (hard to tell from the picture...).

Ian

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907

posted on 29/9/15 at 02:18 PM Reply With Quote
If it was mine I would chop a small amount off the 4-1 and round up the end.

Weld on a bigger link that suits the can inlet.

Please bare in mind I don't know the sizes.

Paul G


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Nickp

posted on 29/9/15 at 03:28 PM Reply With Quote
^ What everyone else said then
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