globalhead

****! I didn't realise at all else I would have helped if I could... I thought you'd stopped to strap it down a bit more - you should have asked! I was too busy trying to get home and go pub to notice - apologies. It was anight for dodgy tres - my left rear was deflating which is why I stopped (for air).

Hi, Ashcrofts are excellent for their gearbox work, BUT when I had them replace the gearbox in my S1 Disco I was less than impressed with the service from their service centre who remove / fit the units. It was a while ago now admittedly, but prior to the work being done I had removed the large lover cover and PTO cover on the transfer case to investigate the problem I had (turned out to be the old chestnut - transfer input gear / mainshaft wear), and as I didn't have new gaskets I used a cornflake packet. Normally I'd never do that - but I knew it would be going in to Ashcrofts within a couple of weeks so thought I'd be OK. On taking it the service centre I mentoned this - and was told all gaskets would be replaced with new items. Got the car back and within a week it developed a leak from the transfer case - from the PTO cover AND the big cover on the bottom. I live an hour's drive from Luton - so ended up fixing it myself. Guess what - the same cornflake packet gaskets were still fitted with the addition of bathroom sized quantities of silicone. I was not impressed! About six months later the box then developed a leak from inside the bellhousing - which was fixed under warranty without any difficulty. I mentioned about the gasket thing - and the service centre owner (called Dale I think) swore blind that what I'd observed was not possible. Well I wasn't making it up, and I'd not been smoking anything either! Dave.

Fair comment! Thing is though - us techy types have to spout our carp - how else can we compensate for our lack of friends, white complection (from sitting at our 'puters day and night), and genetic inabilities with women! Obviously I'm the exception that proves the rule I should add (no - really....).

Well, I've had a read through the thread, and generally speaking I think most things I can think of have been said already. The airflow calculations are probably a bit high imho as the volumetric efficiency of each engine hasn't been considered (vol eff = how efficiently the engine pumps air into itself i.e. theoretical max airflow / actual airflow), I'd hazard a guess at 80% for the type of engines being discussed (and its a wild guess at that). Basic theory would be to keep the pipes as large, as straight and as short as practical. A slighly rough internal surface on the pipes is better (as if rubbed with 180grit) as it trips the boundary layer flow in the pipe from semi laminar to turbulent. This means that the velocity profile across the duct is flatter - or to put it differently - the layer of slow moving air near to the pipe walls (the boundary layer) will be thinner; and hence there is a larger area of faster moving air. For this reason my restrictor drawing mentioned above carries a note stating something like... "After final machining polish internal surfaces of component using grey scotchbrite or similar to produce a lightly burnished finish. Minimum material condition must not be exceeded by this operation". Placing the inlet in a position where it will draw cool air is a big advantage (as mentioned). I would think that ram air effects at off road speeds will be negligable - and probably not much better at road type speeds. Perhaps on a dyno you would notice a slight increase, but I would be quite surprised if the driver would feel any difference. On a racing car you would point the intake in the direction of oncoming air, but if it were my vehicle I would sacrifice that tiny (if any) power gain in order to avoid sucking rubbish into the snorkel. When designing intake systems there is usually a reasonably large amount of analytical work done using simulation programs to size the pipe diameter. While large diameters are good for steady state airflow - they are bad for throttle response because you have a larger volume (and therefore greater mass) of air to get moving when the throttle is slammed open. Given the long lengths being discussed it probably takes several engine cycles to consume the volume of air sitting in the pipe, so throttle response may be so sluggish (in the grand scheme) anyway that any change from one pipe size to another is negligable, but it is worth bearing in mind. Cheers, Dave.

Hi, Sorry to make this my first post on your forum, but one of my friends from ORRP alerted me to this discussion, and I'd like to set the record straight. The restrictor for the Saluki Racer was not designed by Steve Lund, it was designed by me. I am a professional automotive engineer with many years experiance in race engine engineering (WRC and IRL being among the forulae I have worked in), and I designed that part - through Steve - as a favour for Team Saluki. The restrictor has since appeared on Steve's site being passed (in my view) as his own work. This view is reinforced by the comments above. If ever evidence was required of my intellectual ownership of the design, I have original drawings and emails etc from the time I did the work. I have no interest in starting an arguement here, but frankly it makes my blood boil when I hear of "Steve's" restrictor - especially in light of other issues that have existed between Lund Engines and Team Saluki. Dave.