McBreadhead Posted July 9, 2006 Share Posted July 9, 2006 Recently upgraded my std crossflow to a 1760cc unit with forged pistons, stage 4 race head, Cosworth A6 cam, running on twin 40 DCOEs with (only) 30mm chokes. This is supposed to put out 160bhp but I had it rolling road (carb) tuned last month and it only managed 134bhp. I know you can't compare rolling roads but this discrepancy seems excessive. Roughly how much power would be liberated increasing the choke sizes? Furthermore the fuel consumption seems poor at around 20mpg for a steady 75mph cruise around 4,000 rpm. Took car onto track this weekend and it bogs down badly under 2,500rpm plus constantly stalling on overun. People have suggested timing is way too advanced. Obvious route is to take it back to rolling road and get them to sort but unsure of where I stand in terms of should I be made to pay for extra work or should they do it for free? Would/should they be able to sort timing issues? To compound matters, the engine installation (engine was a sealed unit) has been performed by a collection of professionals which means I do not have 'continuity' of service making responsibility difficult to apportion. Should the rolling road be able to sort the ignition problem (preferred for continuity) or am I better off taking to Caterham specialist? They did originally mention they had difficulty getting their system to communicate with the ECU so I wonder if they have had to make too coarse an assumption with a setting somewhere. The iginition is a Lucas competition unit fitted by Roger King and should be worth 5-10bhp more than std Caterham unit. Lots of possibilities I know, but I need to start isolating things in a logical fashion. Any ideas and/or suggestions how I should attack this? Your help much appreciated o wise wuns. Link to comment Share on other sites More sharing options...
Englishmaninwales Posted July 9, 2006 Share Posted July 9, 2006 Nick Sorry to hear it's not running well . I'm afraid I can't help as I know nothing about setting up crossflows, but I hope you get it fixed soon. Maybe it needs a run in fresh N Wales air! Malcolm Link to comment Share on other sites More sharing options...
JampJ Posted July 9, 2006 Share Posted July 9, 2006 When you say they had a problem with the ECU, what system have you got fitted? Cheers J&J JFDI (Just F*****g Do It) Link to comment Share on other sites More sharing options...
McBreadhead Posted July 10, 2006 Author Share Posted July 10, 2006 It's an Emerald EC3 from memory - is this significant? It has Roger King's stamp upon it and has a 3 pin port for analysis/download purposes. Link to comment Share on other sites More sharing options...
Petrolhead Posted July 10, 2006 Share Posted July 10, 2006 From my experience the A6 is quite a wild cam and the car will feel boged down at lower revs not coming onto song untill about 4000 rpm The chokes seem a tad on the small size and would benefit from going larger 34mm Fuel consumption on a Xflow is never the best and 20mpg sound about right especially concidering the state of tune NE7Club Web Site R5 no 65 😬 Link to comment Share on other sites More sharing options...
McBreadhead Posted July 10, 2006 Author Share Posted July 10, 2006 Petrolhead, thanks for advice - I was thinking 32 or 34mm chokes. Will this deteriorate fuel consumption further tho? Yes A6 is pretty wild and I'm happy to accept some loss of tractability but it's as if a Ford Fiesta would out accelerate me under 2,500 rpm!!! I also recall being driven with this engine in another car in May and it pulled cleanly all the way, admittedly using 32mm chokes. Wonder why the engine is stalling so much? Is this the ECU not working properly or timing too advanced? Link to comment Share on other sites More sharing options...
ashaughnessy Posted July 10, 2006 Share Posted July 10, 2006 You haven't said much about how the spark is controlled. Do you have a distributor or is the ECU an all singing all dancing 3D mapped thingummy? Also, as someone else has said, 40DCOE carbs sounds small for your spec. I was advised to go for 45DCOEs (can't remember what choke size) to go with a 1700 engine with a 244 cam, a much more mild cam than yours. What about exhaust? I don't think you need to take it to a Caterham specialist, you need to take it to an engine specialist. This may sound unfair, but the way you tell things it sounds like you've taken a bunch of disparate components from disparate suppliers and thrown them together in the hope they'll work. I think you need to get someone to match your carbs, ignition and exhaust (and possibly cam timing as well) to the engine spec and then put it on the rolling road for final adjustment. If you can get one person to do all of it so much the better. It could also be something broken, though. Do you have any sensors (e.g. throttle position sensor) feeding the ECU? Whereabouts in the country are you? Then someone could recommend an engine fettler for you. Anthony Link to comment Share on other sites More sharing options...
McBreadhead Posted July 10, 2006 Author Share Posted July 10, 2006 Anthony, Point taken - it does sound a bit like a bit of a goose chase but that is not how I planned it! I originally wanted a 7 specialist to do all the work which he did to the point of getting the engine running (it was a sealed unit using carbs, Lucas competition ignition and dizzie, and 4 into 1 Caterham exhaust from my current car), but he couldn't get a rolling road slot booked for weeks. So in desperation I took it elsewhere and they naturally had no history with the car but did as best they could. It was there they said the Emerald EC3 wasn't communicating with their set up which to me sounds like a fairly crucial component to include/match. The carbs are same size and type as on the engine I bought (and which I still have), although they ran 32mm chokes. However these were relatively worn out compared to mine, hence I swapped them over. Not sure if the EC3 is fully mapped 3D item but as I have a dizzie I assume not. As you see I'm not that technically literate, and as I don't have a garage or tools I'm a bit helpless, hence I need to know where to focus my efforts on commissioning appropriate 3rd party experts. I guess at this point I'm unsure of who to go back to, compounded by awkward logistics of getting car to either. If I can iron out certain possibilities it will make the task easier I hope. Car based in South Bucks or South Hants. Appreciate your help so far.... Link to comment Share on other sites More sharing options...
Petrolhead Posted July 10, 2006 Share Posted July 10, 2006 I would say go for 45s if you want a cooking engine that will extract the most out of it. I would also say that 45s with a 244 is probably a waste. Stick with the 40s with the 34mm cocks and that should help drivability Good luck NE7Club Web Site R5 no 65 😬 Link to comment Share on other sites More sharing options...
Martyn Heesom Posted July 11, 2006 Share Posted July 11, 2006 If the engine was better on the old carbs, would it be possible to refit these, or have the 'new' ones set up (jets, chokes, etc. ) similarly? Regarding the timing, it is not clear exactly what set-up you have got, but again could it not be set up as it was before you bought it? If it is a distributor system, and the timing is too far advanced, it would tend to be difficult to start. Link to comment Share on other sites More sharing options...
JampJ Posted July 11, 2006 Share Posted July 11, 2006 Is there another recommended 7 engine tuner near you? Without the diagnostic equipment, I don't think you are going to get very far. You mention a 7 specialist earlier, couldn't you try them again? Cheers J&J JFDI (Just F*****g Do It) Edited by - johnjulie on 11 Jul 2006 08:51:11 Link to comment Share on other sites More sharing options...
DohNut Posted July 11, 2006 Share Posted July 11, 2006 3D is possible with distributor Assuming you told the garage that you had an Emerald ECU before giving the car to them then they should be able to comunicate with it. They have not said the ECU is faulty which suggests that they know it is their own failure. A very badly mapped ignition (without part throttle advance) would result in high (same as mechanical sparks) fuel consumption. Nick Link to comment Share on other sites More sharing options...
ashaughnessy Posted July 11, 2006 Share Posted July 11, 2006 Petrolhead said > "I would also say that 45s with a 244 is probably a waste" Thanks Petrolhead, you couldn't have told me this before I splashed out on a new set of 45s to go with my 244 cam? ☹️ Actually, I was trying to get the most out of a cooking engine so I think the 45s are probably worth it and the drivability at low revs and part throttle is excellent. McBreadhead - if you have a distributor, is the distributor controlling the timing with its mechanical advance mechanism? If so, you may well want to get the distributor rebuilt by someone like Aldon who will give it an advance curve that suits the engine spec. However, if you have an emerald then I presume the emerald is controlling the timing so maybe this isn't relevant. However you'd definitely want to get the emerald sorted and if your original rolling road couldn't do this then I don't see how they could do a proper job of setting up. Another thing worth thinking about - what about the cam timing? You might be able to adjust this to give better results as well. Anthony Link to comment Share on other sites More sharing options...
Petrolhead Posted July 11, 2006 Share Posted July 11, 2006 Sorry ashaughnessy, but to be fair I am not the xflow guru and it has been quite a while since I played with them so views change Lnyway, when you decide to got extra big valve and 264 cam etc etc you 45s will be ready for even more power 😬 Now I have just sent into the upgrade route so sorry again 😬 NE7Club Web Site R5 no 65 😬 Link to comment Share on other sites More sharing options...
McBreadhead Posted July 11, 2006 Author Share Posted July 11, 2006 OK, here's an update and thanks all for advice so far. I'm sticking with 40 DCOEs for now, though probably moving up to 32 or 34 mm chokes. ECU is an Emerald M3D which is now 8 or more years old. It uses a throttle pot on carbs, connecting to a Bosch dizzie and Lucas competition ignition. So I guess it's more 2D than 3D in this respect. Spoke to Dave Walker at Emerald who needs serial number to figure out ECU spec which we can then provide to rolling road. Problem is his RR won't do carbs, so hoping and praying the relevant info and connectivity twixt ECU and my local RR can be done. Bit surprised my RR tried to tune the engine without being able to connect to ECU as tuning without seems pointless. Assuming I can get the serial No. info, I then need to invest in related software and cables and provide to RR. Can anyone see any pitfalls here and should my RR be able to work with it? These things aren't straightforward are they! Link to comment Share on other sites More sharing options...
DohNut Posted July 11, 2006 Share Posted July 11, 2006 I would not be keen on letting them learn on my engine when they did not have the bollxx to stand up and say " sorry mate we cant get this to work" My ECU is 14 years old and working fine still - dont let that put you off. Emerald give out software free and cables at a reasonable cost (£15?) I would search out a rolling road that is familiar with the Emerald and who knows about carbs They will spend less time faffing about trying to find the correct screen etc. Just one hours wasted rolling road time buys a lot of petrol and travelling time. Nick Link to comment Share on other sites More sharing options...
McBreadhead Posted July 11, 2006 Author Share Posted July 11, 2006 Nick, I tend to agree with you re a one stop shop for expertise with carbs and Emerald. Any suggestions then? Car based in Winchester at present, tho alternates with Gerrards Cross. Nick Link to comment Share on other sites More sharing options...
Corkheader Posted July 11, 2006 Share Posted July 11, 2006 Nick - I have just had mine sorted by Thom Airey - see my posting last week with phone number and web site details. He is based near Bramdean, not far from you. He has a rolling road and knows his carbs. Did a cracking job on mine and judging by the posts is known to a few people on here. Link to comment Share on other sites More sharing options...
Manxseven Posted July 11, 2006 Share Posted July 11, 2006 Tom Airey or Slark Engineering (Amesbury, Wiltshire) see here Caterham Fireblade here Edited by - Manxseven on 11 Jul 2006 18:50:31 Link to comment Share on other sites More sharing options...
McBreadhead Posted July 11, 2006 Author Share Posted July 11, 2006 Oh boolooks there's no manufacturer name or serial number on the ECU. I had assumed it was an Emerald as Caterham sold me the car with an Emerald info pack as part of the docs. Time to get a large hammer........ Link to comment Share on other sites More sharing options...
Jorgen Posted July 12, 2006 Share Posted July 12, 2006 Could it be a DTA unit. The casing looks a lot like the emerald. I have one so you can drop me a picture and i can compare with mine. The plug could also be a good identification mark as they are different between some of the makes around. Jorgen Link to comment Share on other sites More sharing options...
McBreadhead Posted July 12, 2006 Author Share Posted July 12, 2006 Jorgen, I may well just do that, thanks for the offer. Mine's an August 1996 registered car tho I can't confirm if the ECU was fitted then. Photos to come. Just been informed by The Maestro (RK) that 34mm chokes is definitely the way to go. Problem is I now have to get car re done on RR , then get ECU sorted, hopefully by same RR. Tom Airey sounds damn good but it depends if he can work with my ECU, once I get it identified that is. Nick Link to comment Share on other sites More sharing options...
McBreadhead Posted July 14, 2006 Author Share Posted July 14, 2006 Latest on my ECU........ "It's an Emerald but not as we know it Jim........." V early version running on...............................DOS!!!! 😳 🙆🏻 Uses coolant temp and throttle position sensors, not much else apparently. Can the software get me back to 7th heaven??? Link to comment Share on other sites More sharing options...
DohNut Posted July 14, 2006 Share Posted July 14, 2006 And revs surely 🤔 Nick Link to comment Share on other sites More sharing options...
McBreadhead Posted July 14, 2006 Author Share Posted July 14, 2006 Nah, don't need revs! I hover just below the red line thingy. Link to comment Share on other sites More sharing options...
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