C7JFM Posted November 22, 2002 Share Posted November 22, 2002 Apart from the throttle bodies what makes a VHPD different to a standard 1.8 K ? I am assuming a different crankshaft, pistons and valve gear. Link to comment Share on other sites More sharing options...
scooby dooby doo Posted November 22, 2002 Share Posted November 22, 2002 The main difference is the head. This is an entirely different casting (although it has some similarities with the VVC one I believe) which much more room and larger ports to let more air/fuel mixture into the combustion chamber. It will therefore also have bigger valves. The camshafts are much hotter than the standard ones and a spec above the supersport cams as well. They use mechanical instead of hydraulic followers to cope with the increased revs. The cranshaft is also different as you say - it is a different type of steel that is suitable for the nitriding process which hardens the surface. The rods are different as well (not sure in what way though) and the pistons are forged - so they can withstand the greater temperatures. Some improvement is due to the 4-2-1 exhaust which should be the first upgrade over the standard exhaust for almost everybody (unless you alread have the competition, long primary 4-1). The ECU is also very different. Can't remember who makes it, but it ain;t Rover or Caterham You also get a different colour plug lead HOOPY 500 kg R706KGU Link to comment Share on other sites More sharing options...
F355GTS Posted November 22, 2002 Share Posted November 22, 2002 Hoopy I think I'm right in saying that virtually all the VHPD ECU's are Rover Mems with a different Map to the Supersport or 'std' ones. I think a few towards the end of production had the Y2k kit which came with Roller Barrel TB's and an MBE? ECU. Even when Caterham fitted PTP TB's they persisted with the Mems and original Map much to the annoyance of Jue Thompson and others Mark Link to comment Share on other sites More sharing options...
scooby dooby doo Posted November 22, 2002 Share Posted November 22, 2002 I thought they were all MBE's thorughtout the various TB setups... Its got a MAP sensor in the ECU which the MEMs doesn't have... *confused* We can settle on the ECU being non-std anyway - even if its only a software change Did I get the rest of it right then 🤔 Cool ❗ 😬 HOOPY 500 kg R706KGU Link to comment Share on other sites More sharing options...
CHRIS CLARK Posted November 22, 2002 Share Posted November 22, 2002 The VHPD (Very High Power Derivative) uses the larger valves & ports + nitro-carburised crankshaft (for longer life). Forged pistons, Higher lift camshafts with longer duration & modified MEMS ECU (system 1.9). That is the spec as I know it. The KV6 manifold/tb's were changed to the PTP type towards the end. Clamshell Club Founder Member and stationary engine enthusiast. Link to comment Share on other sites More sharing options...
Gridgway Posted November 22, 2002 Share Posted November 22, 2002 solid lifters too? Graham Link to comment Share on other sites More sharing options...
c21vhpd Posted November 22, 2002 Share Posted November 22, 2002 I thought they were all MBE's thorughtout the various TB setups... Hoopy, I'm most disappointed - we had this very discussion in the other place not so long ago... Honda Passion Orange, 640kg , and proud of it 😬 Link to comment Share on other sites More sharing options...
V7 SLR Posted November 24, 2002 Share Posted November 24, 2002 Hoopy, all MEMS have an internal map sensor. 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...
scooby dooby doo Posted November 25, 2002 Share Posted November 25, 2002 so what is the ECU then 🤔 *confused* *confused* *confused* *confused* *confused* *confused* *confused* *confused* *confused* *confused* *confused* *confused* *confused* *confused* *confused* *confused* *confused* *confused* *confused* *confused* *confused* *confused* *confused* *confused* *confused* *confused* *confused* *confused* *confused* *confused* *confused* *confused* *confused* *confused* *confused* *confused* *confused* *confused* *confused* *confused* *confused* *confused* *confused* *confused* *confused* *confused* *confused* *confused* *confused* *confused* *confused* *confused* *confused* *confused* *confused* *confused* *confused* *confused* *confused* *confused* *confused* *confused* *confused* *confused* *confused* *confused* *confused* *confused* *confused* *confused* *confused* *confused* *confused* *confused* *confused* *confused* *confused* *confused* *confused* *confused* *confused* HOOPY 500 kg R706KGU Edited by - hoopy on 25 Nov 2002 00:14:57 Link to comment Share on other sites More sharing options...
c21vhpd Posted November 25, 2002 Share Posted November 25, 2002 Mine (wa)s a MEMS, but my VHPD is circa '97 - I can't speak for what they got after that. Honda Passion Orange, 640kg , and proud of it 😬 Link to comment Share on other sites More sharing options...
Peter Carmichael Posted November 26, 2002 Share Posted November 26, 2002 Worth pointing out that Nitriding and Nitro-carburising (AKA Tuftriding) are two very different processes. Nitriding requires a different steel (EN40B) which cannot be cast, so nitrided crankshafts are machined from billet. The process is expensive as the nitriding process causes the crankshaft to swell and final grinding of journals has to be done after the nitriding. You have to set up the crank on grinding equipment twice over. Nitro-carburising is simpler and can be applied to more basic cast cranks. The VHPD crank is a nitro-carburised cast crank. Link to comment Share on other sites More sharing options...
scooby dooby doo Posted November 26, 2002 Share Posted November 26, 2002 How easy / expensive / useful is tuftriding a std crank going to be 🤔 For example - I going for a std crank but steel rods/forged pistons and a std (but ported with bigger valves) head and 740 cams. I'm working on the idea of an 8000-8200 limit. What will tuftriding do for me 🤔 Yes it will make the surface harder - but 1.8 cranks are fairly cheap and plentiful anyway - so if that's not the weakpoint, and the cost is similar to getting a replacement crank, is it worth it 🤔 HOOPY 500 kg R706KGU Link to comment Share on other sites More sharing options...
oilyhands Posted November 27, 2002 Share Posted November 27, 2002 Point of order Peter, EN40B can be forged so not all cranks are machined from a billet, many are made using conventional forging processes followed by machining, nitriding and then polishing to size. Tufftriding costs about £50 and should include a polish to the journals, as well as hardening the journals it will improve the fatigue life of the crank, 1.8 cranks seem pretty good... Tufftriding can be applied to a variety of steels and even cast iron, typically the stems / complete valve on a K series is tufftrided to prevent siezure in the steel guides. Oily Link to comment Share on other sites More sharing options...
Paulo Posted November 28, 2002 Share Posted November 28, 2002 As a matter of interest, how much power can a std. 1.8 crank withstand ? Upgrade plans afoot. Link to comment Share on other sites More sharing options...
Peter Carmichael Posted November 28, 2002 Share Posted November 28, 2002 Mostly cranks fail through fatigue, so it depends how long you want it to last for. VHPD cranks have been turning out 220bhp happily. It is important to keep some form of harmonic damping with a cast crank and if the flywheel or reciprocating masses change significantly or you change to a race clutch then the crankshaft is going to face a tougher life. Link to comment Share on other sites More sharing options...
Bob Corb Posted November 28, 2002 Share Posted November 28, 2002 Is the ignition system on a VHPD engine any different (apart from the ECU and spark plugs) to a std 1.8. Its just that I'm collecting parts to build a VHPD motor and have a std K dizzy and leads but no coil yet. Is the K std coil up to the job or should I look for something more upmarket?? I dont have a single coil on my current engine as its an EU3 VVC. Bob Link to comment Share on other sites More sharing options...
Miraz Posted November 28, 2002 Share Posted November 28, 2002 Bob - you may as well use the twin coil arrangement from your existing VVC motor with the VHPD motor, this would also save you the trouble of running the dizzy. Link to comment Share on other sites More sharing options...
Bob Corb Posted November 29, 2002 Share Posted November 29, 2002 Geoff My old VVC motor is a new EU3 one so the coils are too long to fit on a VHPD head. Also I'm actually going to fit a Rover Mems 2 ECU ( ) so I cant drive a distributorless ignition...yet. Bob Link to comment Share on other sites More sharing options...
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