SteveB

Thanks Paul. Glad to hear some feedback on the new surface - I never made the test day. I got quite good at starts last year, best 64ft was 2.03 :) perhaps I'll see the 1.9s this year. Weather.co.uk says dry on Sat but rain Sun pm :( SteveB

Usually I got called lucky 'cause disasters happened very shortly after the rolling road session....its tempting fate to say I can be called lucky for great result....... Its my first event tomorrow, with all the extra power I may be able to go faster up the hill without having to drive any better 😬 SteveB

I haven't bothered with the other forum today - I heard that the thread was hijacked - fortunetely the culprit doesn't post on here as far I know.... We onyl had time to try two trumpet combinations. The unequal ones I was running last year, and all the same as V7SLR has (150mm). The latter gave 11bhop extra and loads more torque after 6500, the former gave less after 6500 but better torque below 5000, between 5000 and 6500 was mostly uneffected. Didn't try double injectors, or a lambda in each primary (not sure how that would be done without a special manifold and mods to the software to monitor all four cylinders. Last year we did try altering the fueling on pairs of cylinders at a time but it made no difference. It was hoped that the pairing the cylinders with the same length trumpets and mapping them as pairs would help but it didn't make any difference. DW is going to do all these sort of experiments on a 1.9 he's been lent using his dyno making it very easy.....all sorts of combinations of manifolds, exhausts, cam timing, and induction. OPriginal plan was to discover why the caterhams always beat the tranverse installs in Elises/Exiges/340Rs...but we seem to have cracked that by accident now!!! There could be something to be had from 45mm TBs. DW wondered if there was any point unless the port entry diamter was increased. Oilyhands thinks there could be something to be had - I'll, let him explain! not too sure what my CR is but given that I had abotu 40 thou off my old VHPD head and only 5 thou off this one so far, I could go higher on CR. But looking at the theoretical max of 96lbft per litre from pump fuel, and that I'm already on 90.5lbft per litre, there isn't really much more to come - not a peak levels anyway. However other areas of the torque curve may still have something to give. Things I have left to try for more power are running a cat pipe that is the same diameter as the rest of my system. Manifold end and silencer are both 2.5", but the only cat pipe I had available was 2.25". That might give a little extra... Also the Caterhams use different cam timing, according to DW use 140/110, according to Nige/Oily use 140/115. Whcih ever it is its not the same as my 130/110. And the Caterhams only showed gains with the 1444s over the 1227s with more lift on the inlet cam. So that might help me. I can feel a return visit to Emerald looming SteveB

Its useful for me that its so far away - it gave me a chance to put 200 miles on my fresh engine, driving there in the morning SteveB

I noticed at Emerald that they now have a coating on the rollers that prevents wheelspin.... SteveB

Johnty, You may find that my map will be good for you to use. I have the same induction (inc trumpet lengths) as V7, a very similar dimensioned manifold compared to that which Nige has (AFAIK). My head has slightly larger ports due to the bigger inlets I have, but not much more, so I suspect my map would be a good starting point - what do you think Oily? When mapping we didn't need to add much fuel if any, just adjust my 1.8k map slightly. I'm running my original 234cc injectors at 3.9bar. It surprised me that I didn't need to fit the bigger injectors I'd brought along to Emerald. DW said somewthing along the lines of "I think the 1.8 was just p*ssing the fuel out of the exhaust and the 1.9 is letting it all burn". DW has a copy of my map that I'm sure he'll email if you want to try that one Johnty, or I can download it tonight. Nige, I've not looked at Mick's piston damage yet, but mine was quite minor compared to that you describe above. But my head was a fresh one that hadn't been skimmed to within an inch of its life. After the contact I called scholar and spoke to their engine builder and he told me that with a heavily skimmed head even the 32.5mm valves may touch - they had on his own engine.....I guess the wayfor you to tell will be to compression check your engine, but given the results you've had I''d say that you don't have any bent valves... SteveB Edited by - SteveB on 13 Apr 2005 09:35:07

...and the bent valves.... SteveB

PS get well soon

PS get well soon

Yep - people can post all they like about one head porter being better than another...but the rolling road results speak for the quality of the porting, and we have a nice consistant set of results at Emerald from DVA heads compared to others! I'm still interested in the bore and lengths of the manifold you're using...although they don't seem to be so important now DW and I stumbled on the "missing link" that used to give Caterhams more power.... SteveB

Interestingly, I have an airbox and also a casing around my filter which is fitted to the side air intake, such that the enigne will only draw air from outside of the engine bay. DW pointed a large fan at the side of the car to blast cold air at my air intake. He does similar for caterhams, pointing the fan at the filter. When we changed trumpet lengths we did the first run without the airbox on and gained about 4 bhp from the trumpet change. Once we knew it worked well we put the airbox back on and then gained another 8bhp - probably a combination of pulse reflections (or whatever the technical term is) and guarenteed cold air from outside of the engine bay... SteveB

Looks like Dave and I were posting at the same time!!! SteveB

It was true about the 20bhp difference.... I have been tuning my Elise since 1998, and every engine spec I have tried has always been beaten by Caterhams running the same spec, with the same level of head porting by the same porter (Dave Andrews) on the same rollinng road (Emerald). No-one was really sure why...and the only real differences were that the high powered caterhams are usually dry sumped, and the obvious exhaust system. I copied a Caterham manifold for dimensions and released 30bhp from my engine of the time for just the exhaust system change - so it can be seen that the correct lengths and diameters to match your cam timing and induction do make a whopping difference, but that change still only gave me 220ish bhp, not the 235+bhp that the Caterhams were getting. I fitted a dry sump but gained nothing, except reliability and 10k of weight! Dave Walker at Emerald has almost finished his dyno cell, and had planned to put this issue to bed once and for all by running the same 1.9k with both the Elise and Caterham exhaust systems that have the best results...and also try different induction, etc.... But now there is no need, because yesterday at Emerald: *Elise beats Caterham shocker* From a DVAPower head and Scholar 1.9k block, I had a repeatable 245bhp, found on several back to back runs where the map was being tweaked to get the AFR spot on everywhere. It only managed 172lbft compared the mid to high 170s that several Caterhams have managed, but I can't have everything !!! This wasn't a case of "let let the car cool down, open the doors, and do one power run so we can tell everyone".... And all we had time to do was map it and try a different trumpet length combination from that which I arrived with. Cam timing wasn't played with, nor was my exhaust system - I have a cat replacement pipe that is 2.25" OD where as the manifold and silencer are 2.5", so there might be losses due to that - or there could be gains..will have to wait and see until I can get back to Emerald to do some fine tuning! I put the great results down to the head porting by DVAPower, and finally arriving at a good match between cam timing, manifold/exhaust system and induction. Thanks also Dave Walker at Emerald for working his magic on the rollers, base power run after mapping was only 234bhp/173lbft.... Chuffed of Abingdon :)

I've just compared the dry sump pan to a standard sump and it has the same horizontal fixing holes. SteveB

That's my advert... The connection back into the sump is at a different height to the steady bar fixing nearby (not used on the Caterham but is on an MGF) and this should protect the elbow. I can take some photos from a different angle to show this if you're interested. The scavange pumps are designed to fit to the side of the water pump, but I have no photos of it installed. SteveB