Bill Shurvinton

Just gotta share. ricardo.com are now selling a reprint of 'high speed internal combustion engines' by Sir Harry. IMO this is one of the most important books ever written on internal combustion, from a genius and true pioneer. Anyone who loves cars owes this man a debt. Its technical, but worth reading just to realise quite how much they had worked out by 1930. Humbling in places in that respect.

In case anyone was after trying Chris Good's Emerald AFR mapping software I have finally received a delivery of LC-1 lambda cables which I am offering to all se7ners. Sorry for the broadcast, but I have lost track of who had expressed an interest. Bill

But do you mean friction or hysteresis? There are 2 different phenomena. For a rolling road where you do a coast down test either of these are corrected out, so the magnitude is of little impact. If you are after an accurate measure of the actual torque you should be looking at hub drive anyway.If you are on a slippery, old, ill maintained set of rollers wheel spin will of course mess everything up. You will have to excuse me being a little cynical about being chosen for emissions testing being a measure of goodness. Its like saying the EU mandates catalytic converters, so they must be the best way to reduce emissions. Thought: most american nuckle draggers take their hopped up cars to dynojet dynos to get their willy waving print outs. These are all single roller. They are pure inertial units and about as accurate as a wet finger. BUT they are cheap, so lots of speed shops buy them. The hot rodders are happy, as they give inflated Wheel HP figures. But if everyone uses them, then they are the defacto standard for willy waving wars between racers. Doesn't mean they are good. Possibly the TaT roller IS very good. If so its a bargain at around 20K. I will find our more. I am happy to be proven very wrong in my concerns.

Drag? Drag is an aerodynamic phenomena. I have yet to see a coherent argument for a single roller being better in any parameter other than cost. That TaT roller is very cheap. Tat also do twin rollers. Why? If I can find some hard facts I can make up my mind. At the moment its all pub talk. For years everyone said that the emerald brixton rollers were spot on. Sadly they were not, but this was only discovered when they were decommissioned. The new ones WERE calibrated, and seem to read 5% less than at Brixton. So now when anyone who is not an accredited engineer says a rolling road is accurate I put the onus of proof on them to show this.

Still not convinced about that TaT road.

If you look at the design brief that was handed out I expect that a couple of things were high in the list 1. Able to be made in quantities exceeded 1million per annum in factories all over the world. 2. Able to meet the US 100K mile (or is it 150K now) certification 3. cheap to build Possibly fraud motorsport aspirations were around 50 in the list. Bling value was probably not there at all.

Wrong Dave? Anyway, given that quality widebands give you log outputs of AFR vs RPM and TPS and that people are writing scripts to do the same with Emerald, its already happening. Auto spark tuning is still a little way off mind, but coming.

Actually the TEC is a fine ECU, very popular all over the world. It has a LOT of features which is why it is confusing. For example the alpha-n/speed density blend feature is really nice. They were one of the first to put in autotuning. A wideband (a HEGO is not a wideband BTW) would speed things up enough. Suspect 20 mins with the manual and i could work it out.

In fact, for a non-hairy engine MAP is directly linear to load. PV=nRT is the ideal gas law. For an engine you need to add the volumetric efficiency to that. So at 1bar (atmospheric) to 2 bar, MAP doubles, so fuel doubles (the ECU should automagically sort out density changes due to IAT). Very easy if you look at it the right way. Oddly people who understand TPS systems have real trouble with speed density and vice versa. which ECU is it?

wrt monitoring lambda on all headers. More afforable technology is in place to do this, and in theory if the M3D has a spare serial input it could monitor them there, rather than eating up 3 analogue inputs. However...Individual cylinder trim is most useful on V8s with central 4-bbl inlets, where you get mixture distribution issues so one pot is running lean. With a good zorst and IRTB inlet this should not be an issue. Don't think that thermal gradients would matter much either across a small head. What little evidence I have shows that on this sort of engine sequential plus individual trim would get you no more than a couple of percent more ( say 5 HP on a 250HP engine) and would take a LOT of mapping to get right. Only worth it for those who REALLY have to win. As ever happy to be proved wrong :-)

You need to get in touch with my friend Marco in Dallas. he has just rebuilt a series 3 as a race car with a pre-Xflow (although not road legal). Blatmail me and I'll let you have his email address

Sadly VAT and shipping make it a little higher, although I am trying to get to grips with the new loopholes on personal imports to see if I can save that. If so the price quoted is within reach (for se7eners only though, Barry boys must pay more). Bill

Not detracting at all. I like all ways of improving performance without spending huge $$$.

http://www.innovatemotorsports.com/resources/news7.php I am first in line to get them hot off the line. shipping end of next week from USA. I have a special price list for all se7eners. email if interested bill at shurvinton.fsworld.co.uk Sorry for posting here. Speedy Steve has given me the membership forms, just slow in filling them in. Bill

Errrm. Nige. My mower has a lighter engine, as does a moped, as does any of the bike engined cars. I think you are missing some qualifiers in that statement. I agree with Dave that Peter C is confusing ECU mapping with inherent throttle response. I am convinced that the 'improvement' in throttle response most people claim from going IRTB is in fact because, at low RPM you go from nothing to full throttle in about 10% of pedal travel .