Englishmaninwales Posted December 28, 2006 Share Posted December 28, 2006 Is there any significant gain in having a 4:2:1 over 4:1 long header exhaust when fitted to 1800 k with SS (correctly timed) cams, standard unported head and supersport plenum (old type)? Cost 2nd hand seem to be £300-500, and I wondered if this is cost effective. malcolm Link to comment Share on other sites More sharing options...
Ash.Bailey Posted December 28, 2006 Share Posted December 28, 2006 🙆🏻deleted cos I was talking about a longer primary 4-2-1 vs caterham 4-2-1. If It aint yellow, wonky and wobbly................ 😬 Edited by - wonkycustard on 28 Dec 2006 12:03:11 Link to comment Share on other sites More sharing options...
Peter T Posted December 28, 2006 Share Posted December 28, 2006 Certainly a 4-2-1 exhaust promotes the torque to be lowered in the rev range as oppsoed to a 4-1.But whether you will gain much from just swapping them without a mapable ECU i cannot tell you. A before and after session on a Dynoe will give you the result. R500 Mango Madness Link to comment Share on other sites More sharing options...
Howard R Posted December 28, 2006 Share Posted December 28, 2006 Hi Malcolm The 4:2:1 is supposed to give more low down torque. It would be worth putting your car on a dyno 1st - to see if it lacking in torque + power - not that I think it is (apart from racing blue Izuzu pickups through Wales 😳 ) Best wishes for New Year H Link to comment Share on other sites More sharing options...
david nelson Posted December 28, 2006 Share Posted December 28, 2006 Malcolm I did this mid season and there is a diffrence. It was the only thing I change but the car felt more alive. I am not sure that it made me any quicker. David Link to comment Share on other sites More sharing options...
Rob Walker Posted December 28, 2006 Share Posted December 28, 2006 Come on Malcolm you know you want it, it is futile to resist. 😬 Link to comment Share on other sites More sharing options...
CageyH Posted December 28, 2006 Share Posted December 28, 2006 Malcolm, Buy this to stop me! Only dead fish go with the flow.... Link to comment Share on other sites More sharing options...
Bozz Posted December 29, 2006 Share Posted December 29, 2006 I've changed from a short primaried 4-1 with cat to CC 4-2-1 w/o cat and IMHO the increase in torque, especially in the midrange, is significant. Hope to do another dyno power run again sometime to confirm what I can feel through my 🙆🏻 😬 Not sure how noticeable or cost effective it would be to change from the long primaried 4-1 though. Bozz McLaren Orange and Black 1.6SS 6 Speed here Link to comment Share on other sites More sharing options...
Jason Plato Posted December 29, 2006 Share Posted December 29, 2006 I changed from 4-1 > 4-2-1 Caterham systems and there was an increase in midrange torque with no losses at peak, tested at Emerald. The 4-2-1 also filled in a hole at around 5500 of about 8ft/lb. You realy need to optimise the cam timing too, add a larger throtlle body and connect up a cold air feed to the plenhum . here is C7 TOP Taffia Area Rep Link to comment Share on other sites More sharing options...
Englishmaninwales Posted December 29, 2006 Author Share Posted December 29, 2006 Rob W 😬 Dave J: You realy need to optimise the cam timing too, add a larger throttle body and connect up a cold air feed to the plenum The cam timing is as set up by Dave Andrews. Are there better settings for the 4:2:1? I'm restricted (class 2 regs)to the standard TB as fitted to the SS aluminium plenum. Cold air is an easy mod for the forward facing TB Link to comment Share on other sites More sharing options...
Jason Plato Posted December 29, 2006 Share Posted December 29, 2006 I think the cam settings are the same unless you were to experiment on the dyno with the exhaust . I think its more what the mems and IVAC can cope with as overlap and reverse pulse etc than the introduction of the exhaust. are you using a forward facing 1400 plenhum then ?. That has a huge throttle body no worries there then Link to comment Share on other sites More sharing options...
old captain slow Posted December 29, 2006 Share Posted December 29, 2006 Malcolm, It looks cool so what other incentive do you need. Oh! If asked why you did it, the stock answer is it's a safety improvement. C7 CDW Link to comment Share on other sites More sharing options...
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