EFA Posted February 7, 2003 Share Posted February 7, 2003 Well as the secret is out that I have a K-Series engine in my garage, I may as well come clean and suggest that delivery of a set of Caterham roller barrels, loom, MBS and lots of other K-series bits is also imminent. However, Mr Lambert of Caterham Aftersales has written in Febs Low Flying that the Roller Barells are overspecced for a 1.6 litre K. Woudl anyone care to address my concerns that Mr Lambert could be right? or is he talking sweaties what with all those 1.8 innards he has to sell???? Arnie Webb The Fat Bloke back @ 512k Edited by - fast arnie on 7 Feb 2003 23:01:25 Link to comment Share on other sites More sharing options...
Rob Walker Posted February 8, 2003 Share Posted February 8, 2003 Arnie, Its not proven that there is any advantage over the Direct to head TB. Dave Walker ran a K motor on the QED dyno with direct to head TB`s fitted with the butterfies and spindles removed and compared the max power output to a standard unmolested set and there was no difference. Conclusion is that the butterfly and spindle has little if any effect on max power produced. What is also worth consideration that on part throttle the roller barrels perform much worse than the butterlies and spindles due to greater airflow disturbance. So unless the roller barrels are cheapo I would go for the DTHTB`s. As to the 1.8 K stuff Caterham is selling off , the only problem is its all standard stuff the only bits that might be of use in a moderately tuned K would be the crank and thats marginal IMHO. Link to comment Share on other sites More sharing options...
EFA Posted February 8, 2003 Author Share Posted February 8, 2003 Rob, What Mr Lambert is saying is a direct comparison of fitting roller barrels to a 1.6K Supersport, or same engine with 1800cc displacement (my original posting was perhaps suggesting a higher spec engine, but this is just to make certain Blatchatters think i am crossing to the dark side - this 1.6k is not even mine!!) So whilst I agree that on part throttle the roller barrels may perform much worse than the butterlies and spindles due to greater airflow disturbance, this would surely effect all engines. Is there any confirmed link between the induction vacuum of a 1.6 (which will be marginly down on a 1.8) causing a significant side effect to the 1.6 engine - its a bit like when Caterham fitted oversized chokes the VX carb engines - no loss of power, but increased low down flat spots??? How does all this stack up to Lord Carmichaels situ where he uses the same TB's for his 253bhp engine bolte onto a std 1.6 Supersport unit - no they are not roller barells, but they do have the dimensions to support the necessary breathing for his "big engine" as he calls it.... Arnie Webb The Fat Bloke back @ 512k Link to comment Share on other sites More sharing options...
mav Posted February 8, 2003 Share Posted February 8, 2003 More to do with the step between the rollers and the head i think Arnie Link to comment Share on other sites More sharing options...
EFA Posted February 8, 2003 Author Share Posted February 8, 2003 Are the 1.6 and 1.8 head not identical (VVC excepted...) Caterham claim the roller barrels are "over spec'd" for the 1.6. By putting 1.8 internals in the engine Mr Lambert suggests all is then 100% OK. Woudl anyone like to comment on the following two points as having any validity in the above statement: Caterham have a large surplus of 1.8 internals form R500 engines Caterham cannot be bothered to produce a map for a 1.6 on roller barrels for the MBE 967. I think the issue is commercial, not technical, and this is what I am trying to sound out. Arnie Webb The Fat Bloke back @ 512k Edited by - fast arnie on 8 Feb 2003 13:11:33 Link to comment Share on other sites More sharing options...
A10ROX Posted February 8, 2003 Share Posted February 8, 2003 Hi Arnie, I only spoke to Caterham Service yesterday about this they say .... "they say they have tried a 1600 however they concluded that they needed the 1800 capacity since on a 1600 the roller barrels would produce too much fuel mixture ..... that the system was designed for an 1800 ... and that a new map would be required" Still undecided as to the route for more power! the not so light Superlight Link to comment Share on other sites More sharing options...
Rob Walker Posted February 8, 2003 Share Posted February 8, 2003 You are correct the 1.6 and 1.8 K heads are the same. I cannot see any reason why the roller barrels would not work equally well on both a 1.6 or a 1.8. In both cases the inlet ports will need opening up in order that they align with the TB bores. THe VHPD and VVC heads will align without much fettling. IMO opinion and having sucessfully tuned both the 1.6 and 1.8K the 1.6 makes a much nicer smooth free revving engine being square. Link to comment Share on other sites More sharing options...
EFA Posted February 8, 2003 Author Share Posted February 8, 2003 "that the system was designed for an 1800 ... and that a new map would be required" Not really over spec then, just too easy to upsell the 1800 internals as well. I wonder sometimes exactly how dumb Caterham think their customer base is...... The only potntial issue with the roller barells is that the flow rate is able to reduce inlet velocities to the point that the engine has a slightly extended range of inflexibility at the very bottom end. More likely however if it were more seriously cammed I would think. If the 1800 map over fuels, its not rocket science to reduce the fuel/rpm map values slightly.... Arnie Webb The Fat Bloke back @ 512k Edited by - fast arnie on 8 Feb 2003 18:17:41 Link to comment Share on other sites More sharing options...
Gridgway Posted February 8, 2003 Share Posted February 8, 2003 but why on earth go to the expense of getting Caterham roller barrels over other DTHTB's such as Jenvey's? If they are good enough for PC's big engine...?? Graham Link to comment Share on other sites More sharing options...
EFA Posted February 8, 2003 Author Share Posted February 8, 2003 £1650 gets you all the kit - TB's fuel rail, loom, air filter, trumpets, ECU, etc. All designed to fit the car, no messing about and no risk of incompatibility (maybe Mr Lambert might not agree....) Arnie Webb The Fat Bloke back @ 512k Link to comment Share on other sites More sharing options...
Gridgway Posted February 8, 2003 Share Posted February 8, 2003 Hmm, not bad against about £1400 going Jenveys, Emerald etc. Graham Link to comment Share on other sites More sharing options...
EFA Posted February 8, 2003 Author Share Posted February 8, 2003 Graham, Do you have a cost breakdown? Arnie Webb The Fat Bloke back @ 512k Link to comment Share on other sites More sharing options...
Gridgway Posted February 8, 2003 Share Posted February 8, 2003 in da mail! Graham Link to comment Share on other sites More sharing options...
Julian Thompson Posted February 9, 2003 Share Posted February 9, 2003 How much are roller barrels on their own? Link to comment Share on other sites More sharing options...
EFA Posted February 9, 2003 Author Share Posted February 9, 2003 Thx Graham, Guess the trumpets and linkage for £75 can't be Jenvey items - these are well over double that price for the SF version for the VX ! Arnie Webb The Fat Bloke back @ 512k Link to comment Share on other sites More sharing options...
Gridgway Posted February 9, 2003 Share Posted February 9, 2003 yep, probably right Arnie. Graham Link to comment Share on other sites More sharing options...
oilyhands Posted February 9, 2003 Share Posted February 9, 2003 Errr.. Jenvey TBs £560 inclusive Scouse airbox kit, including composite trumpets, throttle linkage, fuel rail mounts, backplate airbox, allows you to retain existing fuel rail/injectors and FPR £310 Emerald ECU £588 Total inc VAT £1458 Total with no airbox, just trumpets £1250, backplate and Pipercross filter £80 Oily Link to comment Share on other sites More sharing options...
kjp Posted February 10, 2003 Share Posted February 10, 2003 'at part throttle the roller barrels will perform much worse' What does this mean? Is this not why we have a throttle? to make the engine perform worse? If you want more torque ehhhh...... open the throttle Can't take the 'air disturbance' argument either. Any disturbance at Part throttle will only improve combustion. I suspect if there is a problem with the roller barrels it's the linkage and throttle rate. Anyway get mine soon (for a 1.6l) maybe I can then comment with authority. Ken p Link to comment Share on other sites More sharing options...
oilyhands Posted February 10, 2003 Share Posted February 10, 2003 Its not just air disturbance it's distribution of air around the port, a butterlfy gives a fairly even distribution of air in an annulus around the port, then swirl and tumble act as the designer intended, on anything other than full throttle a roller barrel will bias the air to the top or bottom of the port depending on design. This makes for some weird part throttle behaviour, you just need to look at a fuel map to see. Oily Link to comment Share on other sites More sharing options...
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