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neal

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neal last won the day on August 5 2010

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About neal

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    LOTUS
  • Birthday 03/05/1978

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  • Name
    Neal McDonnell
  • Car
    98 V8-GT, now sold ;-(

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  1. I once received my car back from a service with a reputable specialist with that very same mistake with the jubilee clips!
  2. Sounds like the engine is overboosting. The ECM is unable to control the boost pressure coming from the turbo. Normally if the boost pressure is higher than required, the ECM will increase the pulse width going to the boost bleed valve. This delivers a greater proportion of the manifold pressure to the wastegate causing it to open more. Likewise the reverse occurs if the boost pressure is lower than required. This feedback look is the primary mechanism by which the ECM controls the boost. There are secondary measures the ECM will take when overboosting occurs in an attempt to reduce the additional stress on the engine, e.g. retarding the timing, descreasing the A/F ratio. However, the effect of these is pretty minor. The are a number of possible causes of overboosting: 1. The wastegate flap is jammed open and not springing back to the closed position 2. The bladder in the wastegate actuator is punctured and unable to open the wastegate flap when pressurised. 3. The hose from the boost bleed value to the wastegate actuator has come loose or is cracked, split, punctured, etc. I'd check these out to start with. Cheers, Neal
  3. One thing to be aware of if that with the standard ECM, you only get the full 11psi boost across the rev range in fifth gear. In the other gears the boost becomes progressively greater as you go up the gears, but is still only 6-8psi up to around 6k rpm. Only above 6k does it increase further, reaching 11psi as you hit the redline: bgraph.pdf (ignore the overboost curve, as far I know that only applies to the Lotus Red Race ECM) I'm starting to sound like a broken record but again this was done to protect the drivetrain, since the car's acceleration or more precisely the torque at the wheels, is higher relative to the increasing overall gearing step-down. You mentioned getting a set of Marcus's chips. But to be honest, unless you're after more that 11psi (and are prepared to take the additional risk), the best update you can get is to have Lotus reflash your ECM with the Sport 350 code. It 'only' costs a few hundred quid (when I had it done a fair while ago, I've no idea of the price now) and has the major advantage that Lotus can reflash it without touching the ECM in your car. No soldering or anything else which might damage your precious and very, very, expensive ECM. In fact I don't think Lotus stock the V8 ECM anymore and you can't even get one from a scrap dealer since they'll only sell it with the engine. With the S350 code, the boost curve for gears 2, 3 and 4 becomes the same as fifth gear. First is still restricted but traction is typically the limiting factor anyway so that's no real loss. I can't emphasise enough the how much of an improvement the S350 code is. It behaves like a completely different car and you can really power through the gears without dropping off boost. Regarding your boost gauge, I don't suppose you have an OBDII scanner? That allows you to read the inlet manifold pressure directly from the MAP sensor.
  4. Yeah, it is somewhat addictive running an overboosting V8! Really shows what it could have done had it not been for the limiting factor of the gearbox. The V8's MAP sensor only reads to 2 bar so you can't see what the max boost the T25s could produce. But I ran an OBDII trace and you could see from the slowing rate at which the boost was increasing that it would top out at approx. 2.2 bar. But the most surprising thing is just how instantaneous the boost comes on without the ECM to feed it in gently. Again this was primarily to protect the gearbox. But I'd imagine another factor was to prevent a lot of V8s ending up in the bushes due to an over ambitious use of the throttle in the bends! Overboosting my V8 was how I managed 179mph at VMax back in 2005: http://www.vmax200.com/vmax-X.php The timing beams were 1.6 miles down Bruntingthorpe's 2 mile runway, using the rest to slow down. The car was still pulling well through the timing beams, it would have been interested to see what speed it could have managed over a longer distance. On that occasion, overboosting the engine was actually a calculated exercise. You'll see from the photos that it was very cold, below freezing for the whole day. I worked out the night before that the inlet air temp running 2.2 bar with that ambient temperature would be roughly the same as 1.75 bar on a hot summer day. So there was method in my madness!
  5. Have a look for the bleed valve - it's about 5cm x 3cm, on the right side at the very back of the engine bay attached to the firewall. It will have a two wire electrical connection and a hose connected to the top and another connected to the bottom. First of all check the electrical connector is secure (but I'd be very surprised if that was the issue since if it's disconnected you immediately get a CEL). Next check the top hose (from the throttle body) is secure. Try connecting your mityvac gauge to this hose and rev the engine hard to see what sort of psi you're getting. Alternatively you could check the hose routing back to the throttle body for any lose connections. It goes through the right side of the engine bay under the quarterlight panel toward the front of the engine, back into the engine bay and connects to the throttle body. Finally (and be VERY careful doing this), you could try disconnecting the bottom hose. This means the wastegate actuators won't receive any positive pressure and therefore shouldn't open, regardless of the manifold pressure. So there nothing to prevent the engine overboosting, up to the limit of the T25s (which is about 2.1 bar). This allows you to check the wastegates and turbos are able to produce more that the 5psi boost that you're seeing. It'll be blindingly obviously if the engine is boosting freely. First of all without the ECM feeding the boost in gently, you'll get a near instantaneous VERY sharp throttle response (don't try it on a corner!) Secondly it will only take a relatively small throttle opening (about third to a half) to reach 11psi. It's a somewhat blunt approach but will straight away rule out any problems downstream of the bleed value. Just be very gentle and only ever feather the throttle.
  6. There are some major differences between the Renault and Lotus spec UN1 variants such as, stronger diff, heated treated shafts, difference gear ratios, etc. However, a lot of the basic components are identical and I believe this includes all the synchro rings. I managed to find my copy of the Renault service notes for the UN1: Unfortunately it only lists the Renault part numbers for the tools used to work with the box, not the actual gearbox components. But it gives full details of the Renault models fitted with these boxes. You could have a look through Autotrader, Ebay, Pistonheads, etc. for one of these models and note its regisatration number and follow up with Renault that way. Certainly if you could get the parts directly from Renault they would be a lot cheaper. However, Renault stopped using the UN1 in its cars long before Lotus did. In fact the Renault UN1 production line was only keep running to build boxes for the Esprit. So Renault may no longer have any spares or Lotus may have bought the all their spares stock to service the Esprit. But it's worth a try to get the synchos from Renault.
  7. The website is currently down, I hope he's still in business, but Kevin at GTO was the expert and supplier of all things UN1 GTO Racing Scarletts Farm Scarletts Lane Hare Hatch Twyford Berkshire RG10 9XE T: 01189 401101 F: 01189 401373 M: 07985 609231 www.gtoracing.co.uk/
  8. I went with a group of exotica to the IOM a few years back for a hoon around the TT. None of us had any problems with the ferry. My car had the the S350 front lip and was lowered so only had a few inches clearance at the front but was fine. The guys who run the ferries were well used to it - they must see a lot of serious machinery - and help you straddle the lips on the ramp at as shallow an angle an possible. Have fun!
  9. Happy birthday Mike! Have fun
  10. Very sad to hear. Brian's always gone out of his way to help at any time.
  11. Alas I can't make this so my ticket is up for sale Sunday is the best day of the event - in addition to the demonstation runs you'll be able to see all the full bore timed runs! Also includes a roving Grandstand ticket so you don't have to stand around all day or struggle to get a good view of the track. I've put it up on Ebay but fell free to PM me an offer: http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=330581522325
  12. Definitely worth seeing at the cinema but I can't wait for the DVD either. I read that the first cut of the film was over 5 hours. And unlike a lot of DVD extras, they left out some incredible stuff, e.g. the European GP at Donington.
  13. Yep, there were four V8s including an S350 at Vmax 10: http://www.vmax200.com/results-vmax10.htm As I recall, Adrian was deperately trying to get the wing off his S350 but to no avail
  14. Happy birthday your Bibsness Have a good one
  15. I was able to get some matching aftermarket condensers for £150 each. I think PNM and SJ Sportcars have them.
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