jackb_ms Posted January 27, 2003 Share Posted January 27, 2003 Dear All I have scaned the archive for as much information as possible but appenrently it hasn't been done on a Caterham. Few names where often mentioned, Opcon autorotor, Eaton M45, and TurboTechnics. I would like to know if soneone did fit a supercharger on there VVC and what kind of result they had. And if they went for a kit or not? Any picture available? If they did go for a kit how did they lower there CR? Jack Link to comment Share on other sites More sharing options...
Luke Beaumont Posted January 28, 2003 Share Posted January 28, 2003 It's something I've given idle thought to, but not much more than that since the kits are IMHO expensive, and I don't have the expertise to pull off a 'roll your own' solution. TT are the only guys I know of doing a kit. The graphs for the VVC Elise on their site are impressive. Obviously a supercharger installation will be measured against the tried & trusted route of cams/ECU/TBs and whilst a 'charger gives lots more torque, cams will ultimately give more power and rev higher, be much lighter rotationally, and cheaper. If it wasn't for the £5k+ price tag though I still think the 'charger would work well for a road Seven. TT reduce the CR by using shorter rods. Link to comment Share on other sites More sharing options...
V7 SLR Posted January 28, 2003 Share Posted January 28, 2003 There are 2 Elises out there with vastly different installations. The TT one uses what can best be described as a belt driven turbo. In other words its boost pressure builds up with revs like a turbo, but unlike a turbo you don't have the problem with having to dissipate heat. The other installation which is far better IMO is Stuart Boffey's. He has a "proper" supercharger which gives full boost at very low revs, therefore he (probably) has to bleed some of that boost pressure off as revs increase. This makes for a very torquey engine, even at low revs. Last time I spoke to him he hadn't got it running or mapped 100% but indications were good. I do not accept that cams will ultimately give higher power over a well set up supercharged engine. How could it? I do accept that a supercharged engine hasn't yet made any serious power in a K, but it's only time. I've given it a lot of thought and spoke to a supplier of superchargers at the Autosport show. In a normal bodied Caterham (as opposed to an SV) you are always going to have trouble fitting it all inside the engine bay. If you go for a medium to high boost installation you will propbably need a cast ali airbox. This is what TT uses, but theirs has space in the throttle tracts for 2 injectors per cylinder. I'm not convinced that this is necessary and makes for a very long throttle body. Too long for a Caterham. It'd stick way out of the side of the car. For low boost applications you may get away with a reasonably strong plastic airbox, but what "low", "medium" or "high" boost means WRT actual numbers is beyond me. I'm not sure wether you will need shorter con rods only, or whether you ought to have a slightly shorter throw crank too. How much shorter I haven't a clue either, but the calculations for determining CR aren't beyond most people. There's plenty of people here who know how to do this. The relationship between boost and CR can't be that hard to determine either. It would be a fun project. I expect the best approach would be to talk with one of the Elise guys first to see what they've done/had done then develop it yourself over a period of time. I might have a go one day. Worcs L7 club joint AO.//Membership No. 4379//Azure Blue SLR No. 0077//Se7ens List Tours Link to comment Share on other sites More sharing options...
R2D2 Posted January 28, 2003 Share Posted January 28, 2003 It seems to me that the modified turbos are "centifugal" superchargers and they may give a crappy throttle response. Centrifugal blowers are "square law" devices. The boost pressure is proportional to the square of the speed and were typically used on fighter aircraft. I think this means that they tend to produce power in quite a narrow band. They seem to have been reasonably successful in Drag racing but I am not too convinced. The old F1 V16 BRM had this type of blower and that was notorious for shredding tyres and axles. I would imagine that control has improved but even so it may be a problem. The traditional automotive blower is a Rootes pump that gives a good direct relationship between speed and pressure and results in the tradtional supercharger "feel". More recently companies like Sprintex (now closed but there are others) have been developing screw compressors and these are quite linear in there speed/pressure response and cause less heating of the charge than Rootes blowers. Anyone tried a centrifugal blower? Link to comment Share on other sites More sharing options...
Chris Jones Posted January 28, 2003 Share Posted January 28, 2003 Serious power? I reckon 270bhp is pretty serious power for a k! Cheers Chris Link to comment Share on other sites More sharing options...
jackb_ms Posted January 28, 2003 Author Share Posted January 28, 2003 Thanks for the info. The room is not a problem me. My Caterham is one of the rare 21. I'm going for a supercharger because i want to keep the caracteristic of the VVC witch is ideal for cruising or playing. Regharding power, i'm just looking for 215-220 bhp which is plenty for me! Anyone nows where Stuart Boffey is? Or anybody has his e-mail? Or Contact details Jack Link to comment Share on other sites More sharing options...
Chris Jones Posted January 28, 2003 Share Posted January 28, 2003 Oh, forgot to mention that QED have done a supercharger conversion - 300bhp and 200ftlb... Link to comment Share on other sites More sharing options...
V7 SLR Posted January 28, 2003 Share Posted January 28, 2003 I tried a sprintex on an A-series engine a long time ago. Superb device and pretty small. It was one of those type that I was discussing at the show. I'd like to try one on a K. Email me direct for Stuart's details. Wouldn't like to advertise them here as I haven't asked him. Worcs L7 club joint AO.//Membership No. 4379//Azure Blue SLR No. 0077//Se7ens List Tours Link to comment Share on other sites More sharing options...
Luke Beaumont Posted January 28, 2003 Share Posted January 28, 2003 Just to save a bit of face Nigel, my comment about the cams was pointed at the TT215 conversion, though my wording was a little sloppy I grant you. Link to comment Share on other sites More sharing options...
Bill Shurvinton Posted January 28, 2003 Share Posted January 28, 2003 A few terminology problems have crept in here. there is a significant difference between throttle response and boost response. The feel of the car is affected by both (and I have seen some very well reasoned arguaments why the level of responsiveness preferred on a se7en is too much of a good thing, but i won't go there.....yet) For those interested in the easy guide to blowers, Corky Bells book 'supercharged' is a ripping yarn., Has some errors and at least for me is a little like a chinese takeaway, but a lot less chewy than much of my technical library. I'll take it down the pheonix on thursday so anyone can have a peek whose there. I can post it to nudger if he's interested. Anyway to the chase: The centrifugal is the most attractive for a K for the following reasons 1. It is the only blow through design 2. It requires least modification and fabrication to fit 3. As a blow through will have the best throttle response (and will work with your jenveys) 4. It is the lightest 5. It is the most efficient Downsides 1. Boost is, as stated square law, so you might only have 5PSI at 4000RPM but 10PSI at 7000. This could be seen as good depending on what you want from your car. The twin screw (as seen in your merc Kompressor) is the next best 1. You get full boost at 3000RPM, so the torque multiplier is everywhere 2. Its not much less efficient than the centrifugal. Downsides 1. Heavier 2. Harder to intercool 3. suck through, so throttle response WILL be compromised 4. Much rework of inlet required 5. 80% more torque at 3000 RPM might not be a good thing for control on damp surfaces. The rootes (Eaton M90) Is the worst, but cheap. What I would like to know is the reasons that a couple of elise TT conversion owners changed to DVA'd NA setups. This would be the most telling as to the compromises that blowers put on the drivability. Link to comment Share on other sites More sharing options...
fatcat Posted January 29, 2003 Share Posted January 29, 2003 End of last summer, I spoke to Turbo Technics about putting their K-series s'charger onto my caterham - they've been putting them on Elises for several years. They had just done a deal with Ministers to be their agents for the South East, IIRC, and since Ministers have a lot of caterham experience (and TT don't) they were also going to look into fitting them to caterhams. I took my SV over to Ministers for a chat about this. They poked and prodded around the engine bay and concluded that it should be possible to fit the TT s'charger to an SV which has a larger engine bay, but a standard caterham was going to be a struggle. Even with the SV , it looked like the mounting might foul one of chassis tubes - could be resolved by cutting out the tube and replacing it with an appropriately shaped new section. Mine's a VVC engine and they were happy with that - the larger valves being helpful, or something. They were going to have a think about it and get back to me but I haven't heard from them - to be fair I haven't chased it either. It might be worth having a chat with them. Link to comment Share on other sites More sharing options...
V7 SLR Posted January 29, 2003 Share Posted January 29, 2003 Luke, I accept what you say about the TT device. Interestingly enough, doesn't this one use the Emerald M3DK? For sure I know that Dave Walker has been interested in one TT project. Also, Bill is quite right about the twin-screw being a sucker, not a blower. This places your TB's further away from your head and does indeed bugger up throttle response. I'd forgotten that. Makes a great noise though. 😬 To expand on Bill's point 5 regarding the centrifugal type... Not only is it light, it is very small (not much bigger than the dry sump pump in my car) and placement in the engine bay wouldn't be too difficult. Consider the application (engine externals only)... you'd only need a suitably inflexible and air-tight airbox on the end of your Jenvey's which is fed from the blower via piece of hose. Piece of cake surely??? I cannot understand why TT have gone to the trouble of installing 8 injectors. This is why their manifold is so long. I wonder if a DVA airbox and Jenvey's would be sufficient if you sealed the interfaces with silicone??? Could be a quick and dirty experiment. Worcs L7 club joint AO.//Membership No. 4379//Azure Blue SLR No. 0077//Se7ens List Tours Link to comment Share on other sites More sharing options...
Bill Shurvinton Posted January 29, 2003 Share Posted January 29, 2003 Note: The airbox is designed to work down to about 2PSI. Therefore you can handle 12PSI boost without any mods as the pressure differential will be the same. I am suspicious that the poor old K can tolerate more boost than that anyway without cubic $ being spent on it. Link to comment Share on other sites More sharing options...
V7 SLR Posted January 29, 2003 Share Posted January 29, 2003 LOL 😬 I think it might be a safer bet to try an outrageously boosted 1.4, or something with a custom liner/piston setup to increase the liner width than to try mild to medium boost from a 1.8 with its "marginally" thin liners. In fact, wasn't the Adrian Newey Elise originally a 1.4 with a reputed 300bhp??? Worcs L7 club joint AO.//Membership No. 4379//Azure Blue SLR No. 0077//Se7ens List Tours Link to comment Share on other sites More sharing options...
Bill Shurvinton Posted January 29, 2003 Share Posted January 29, 2003 Yup, Cubic $ though. £50K to you sir. Link to comment Share on other sites More sharing options...
Peter Carmichael Posted January 29, 2003 Share Posted January 29, 2003 No the Adrian Newey Turbo was a 1.8. Brodie Brittain subsequently reduced the liner ID to 78mm for a more robust production version and the capacity dropped to just over 1701cc. The crank stroke was still 89mm. Link to comment Share on other sites More sharing options...
Bill Shurvinton Posted January 29, 2003 Share Posted January 29, 2003 Whoops, Brain was off. The TT 300HP elise was the 50K 1.4 with a Variable vane turbo. Link to comment Share on other sites More sharing options...
Morls Posted January 29, 2003 Share Posted January 29, 2003 What sort of thing did the VW Golfs and Polos use 🤔 Presumably as the manufacturing volume was high, these would be affordable as VAG 'spares'. I remember being very impressed with what the thing did on a little old pushrod Polo motor. Mark My Caterham Silver Jubilee No. 7 is here with Mavis, under 'Mark's Cars'. Link to comment Share on other sites More sharing options...
Luke Beaumont Posted January 29, 2003 Share Posted January 29, 2003 Ah yes, the G-lader thing here The Polo G40 was indeed a surprising little car. Useful for winding up Elise owners, since with 113bhp driving 830kg, it's only 10bhp/ton shy of a std Elise. Link to comment Share on other sites More sharing options...
Lauben Posted January 29, 2003 Share Posted January 29, 2003 I remeber Sprintex, they did this great kit for the Peugeot 205 GTI 1.9, up to 250HP depending on boost, don't remember the exact hp on the commercial kit, but the numbers where somewhere around 6 sec to 60, and a V6 feel torquewise, you needed a Testarossa to beat it 0-60, and everyone who has ever driven a 205 knows how it did in the twisties 😬 😬 😬 😬 😬 😬 😬 😬 The Slippery Road and Welcoming Ditches Society of 1993 Link to comment Share on other sites More sharing options...
V7 SLR Posted January 30, 2003 Share Posted January 30, 2003 On one demo Pug they even added a dash-mounted boost button which you could press to engage the Sprintex. The mag that tested it thought it was fast (1.9 litre) and then noted that the button hadn't been pushed. To my mind, I can't work out how it all would have worked. I mean without the s/c engaged wouldn't the car drive badly owing to the low compression? Worcs L7 club joint AO.//Membership No. 4379//Azure Blue SLR No. 0077//Se7ens List Tours Link to comment Share on other sites More sharing options...
Lawrence_Z Posted January 30, 2003 Share Posted January 30, 2003 V7 The boost button would typically allow over boost for a short period, by altering the waste gate value. Lawrence Link to comment Share on other sites More sharing options...
V7 SLR Posted January 30, 2003 Share Posted January 30, 2003 Nope... Apparently, on this one the s/c was engaged and disengaged with a magnetic clutch. It was done to try and prove how good the implementation was but there was no accounting for the fact that the engine was probably hampered below the performance of a N/A 1.9 when the s/c was disengaged. Worcs L7 club joint AO.//Membership No. 4379//Azure Blue SLR No. 0077//Se7ens List Tours Link to comment Share on other sites More sharing options...
Lawrence_Z Posted January 30, 2003 Share Posted January 30, 2003 Placebo effect then? A bit like thinking a Caterham demonstrator is standard Lawrence Link to comment Share on other sites More sharing options...
Bill Shurvinton Posted January 30, 2003 Share Posted January 30, 2003 Nige, Sounds like you really DO need to borrow this book, and read the section on vac bypass valves. Link to comment Share on other sites More sharing options...
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