McBreadhead

Not me but there on Sunday in sunny weather. Are you connected with the group of 4 cars on Sun found at Compton Abbas aerodrome?

Wow thanks all for the advice. As I don't have deep pockets the longevity factor is important, so it looks like AO21s for the time being then unless there's a favourable price differential for the AO48s. What is the going rate for a set of 4 fitted and balanced AO21s v AO48s in the south east?

We got there at lunch only to find there were 4 of you there earlier that morning. So come on then who are you ? (I want to join in the fun you obviously had!)

OK just how hairy are AO48s in the wet? Need to replace all 4 tyres on my 96 crossflow which currently has AO21 185s on 14" rims. Getting to point where I'm garaging car over winter now and avoid wet like the plague so it's only of concern when the rain catches me out. Can you drive gingerly on AO48s in the wet and if so is there a sensible max speed? Must say the AO21s have been brilliant but now looking for a bit more than 6,000m life. Will the AO48s give longer service?

Another big benefit of the twin diagonal new style bar is you can retain your standard boot cover as the tubing diameter is small enough (just) to use the same fabric cut outs. I know as I've just had one fitted and saved a good few bob. So Miura did you get your radiator/nose cone sorted?

Just back from hols and drove car yesterday and she flies. Tony Gooding at Redline Tuning tuned her following recommendation from Emerald. He couldn't figure out what was going on when on idle the throttle pot was reading position 4 (in a range of 0 - 7 therefore reading half open). This accounted for massively rich mixture on tickover. Whoever had fitted carbs failed to notice the pot was loose and had moved to this 'mid' position which was crippling performance. Car now pulls cleanly from low revs and spins happily with a steady increase in power. Doesn't stall on return to idle either. No dyno sheet readings but a 145bhp @ 7200 rpm (self imposed rev limit) at wheels max recorded. Will report fuel consumption in due course. Only gripe is the old 30mm chokes were left on my pedal box housing which resulted in steering jamming when turning into my drive, sthg which could have been bloody nasty. Plus air filter nut came loose on way home; however I'm quite vigilant with these and check them during every journey. For ref Tony is the guy who people like Ray Davies uses for his Goodwood race cars. Not sure if anyone else here has used him but I'd never heard of him before on this forum. So a lot poorer but a bit wiser now. As a new boy to this it's very difficult to know who to trust in this game but I'm glad I persevered to iron out bugs and can now hopefully enjoy fruits of my patience. One thing for sure is that as soon as you deviate from any factory standard you are on your own - only real help is from blatchatters so thanks all for your kind words and advice. So when's this N Wales blat then?!!!!!

Haven't driven it yet but my rolling road result earlier today for my 1760 xflow was 145bhp at the wheels. Je suis very 'appy. 😬 😳 I know it's a bit meaningless but it's a damn sight better than 112 at the last attempt. This time it's got 34mm chokes, and an ECU it can communicate with, plus the throttle pot isn't reading half open when at idle! The tester backed off at 7,200 rpm when power was still climbing.... 😳 Just hope and pray it all holds together and drives like it should. Can't wait to road test it and will report back soon.

In a word, mapping, so that the engine's efficiency can be harnessed I guess. Or am I talking boolooks? Please someone knowledgeable rescue me from my ignorance on these matters

Ah yes small holes and cats just don't go; OK for mice tho. How much can I expect from a rolling road in terms of setting up the dizzie to correct advance. Is this sthg they should be able to do or must the factory do it? The settings for my dizzie were for a std 1700 xflow but I'm unsure if the RR adjusted it with new engine. Would they tend to keep a database of stuff or should I tell them what settings should be? I also have a competition ignition which is supposed to produce a better spark. What is the relationship between this, the ECU and dizzie in terms of what sets what? Sorry to sound thick but my next trip to RR must deliver so keen to get all the info in place beforehand.

Just remembered also that when RR set it up, peak power came in at 6,200 rpm. Odd as engine designed to rev to 7,200 so sthg obviously amiss. Does this sound like a timing issue?

Graham, Emerald's RR won't/can't set up carbs period, so I'd rather go somewhere to hit both at same time particularly as they are located in the back of beyond. I now have software and connection lead so am hoping my local RR can conduct tuning to successful conclusion. But wondering if getting Emerald to communicate with RR will magically raise power with current carb settings or whether both must be done 'in concert'. Nick

Emerald's RR doesn't tune carbs hence bit stuck. Tom Airey has been recommended many times, though he doesn't work much with ECUs sadly.

Brent, I did mention it (on about page 47!) as took some pics and sent to Dave Walker @ Emerald. He confirmed it was an early model and they have done a free software/firmware upgrade. Good luck with new engine installation - fingers very crossed for you and here's hoping for happy, stress free high revving. 😬 Danny, No I'm on carbs. Re base timing this must be suspect as everyone I talk to comments how advanced it sounds. Anyway it sounds like I should press on with 34mm chokes and then get it re-tuned. I'll wait and see what RR offers first before casting judgment. However I'm also interested to see the impact (if any) of merely be able to communicate with the ECU.

OK so the saga continues.......... .......I now have my ECU back from Emerald following a software and firmware upgrade. My RR originally set the car up without being able to communicate with the ECU which I found odd at the time but which I didn't fully appeciate significance of. Result is car bogs down badly at low revs, keeps stalling and has diabolical fuel consumption (sub 20mpg at steady 3500rpm cruise). I now think that doing a RR set up without communication to ECU is missing a fundamental set up parameter but as I don't fully understand the relationship between ECU and the RR tune of timing/carbs I would be interested to hear other's views. The car is a 1760 xflow with Cossie A6 cam, stage 4 race head, steel rocker assy and runs on twin 40s with distributor and a Lucas competition ignition. The ECU uses throttle position and rpm sensors, not sure what else but it's an early Emerald system - air temp perhaps? The RR set car up with 30mm chokes which are probably too restrictive so a move up to 34mm beckons. Currently I'm not sure whether to retune the car first with existing chokes, then do same with 34mm? Or do I get them to install 34mm ones and go straight from there? Is there any point doing a RR test with ECU hooked up to see if I get any performance gains on existing 30mm eg would peak power likely increase? Any thoughts welcome.

Tom Airey [www.aireytuning.com]lotus7club.co.uk[/www.aireytuning.com]

Tom Airey [http://www.aireytuning.com]www.lotus7club.co.uk[/http://www.aireytuning.com/]

Haven't used him myself but Tom Airey near Winchester gets lots of plaudits and seems to specialise in carbs for classic and performance vehicles.

Got CC to install a heater a few years back and can't remember which way the pull/push knob is supposed to function. Which is on and off? Doesn't seem to make any difference anyway but would be nice to know if my feet are being gently roasted rather than grilled.

Nah, don't need revs! I hover just below the red line thingy.

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???

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

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........

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

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!