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Posts posted by AJay

  1. Hmmm Andy you raise a good point... I was hoping to have my scramble boost set to .75 bar = 10.87 psi - so I COULD be lucky and just get away with mine being sufficiently inaccurate :P

    TBH.. the difference is so miniscule that I'm not really sure I'd notice anyway! lol


    I have been running 10 psi and have recorded 70-90mph in 5.48secs.

    After you lot frightening me about the tranny i reduced the boost to 9psi and recorded a 70-90 time in 5.8 secs not a big difference but the difference in the way the car drives and delivers the power is quite noticable.

    Not sure where i am going with the boost, the extra tourque is adictive but!!!!!!!!!

  2. The HC engine has an overboost switch set at 12psi which cuts the ignition if an overboost situation occurs, could be plumbed into your boost gauge line if you are worried about overboost.

    The lotus valve thingy is called a dump valve by Lotus technical it is designed as a relief valve for overboost and is set at 10Psi so robin you will have to remove this if you want boost higher than 10 psi.

    Also like everything on the car it only sticks if it not used. the origional boost of 8 Psi should not release the valve under normal conditions.

    When running at 9.5 Psi it operates at spirited driving conditions between gear changes. I have tested mine and it actualy operates at 11psi so not too accurate.

    Hope this helps.

  3. your poor gears.  they'll be in line for false teeth shortly.


    You are right of course.

    I do try to be sympathetic to the needs of the gear box,(no 0-60times and not pinning the throttle until 3rd gear, not using more than 5500rpm, smooth gear changes heal toe etc), but hey its gonna break some day might as well enjoy breaking it.

  4. hmmm interesting

    when driving mine hard i do get a whosh on most gear changes and admit that i quite like it and one reason i have considered fitting it (lends back to my jap days lol) as for the shock where does this come from as the impeller is constantly driven by the exaust but with the valve open obviously does not produce any pressure and once valve shut would build pressure again gradually.


    Good point, as i said only an opinion and i have seen turbine shafts snap with BOV's fitted (could be coincidence).

    But if the pressure takes time to build again as you suggest then this would cause lag when throttle pinned again!! would it not.

    I am probably wrong, as it is not the conventional view. may be i need to read more and stop driving the car.

  5. Mmmm.  Cool, dense air, more power...

    (1) can it be done?

    (2) is it worth it?

    (3) has anyone else done it?

    (4) will my car break if I do it?


    Yes it can

    Yes it is (If you find the parts cheap enough)

    Yes i have

    Not yet.

    I an running at 10 PSI i have not broken any thing yet (probably will) the car has been on the rollers and re jetted to take higher boost.

    Carried out performance tests and 70-90mph in 5th gear time is now down from 8.4sec standard LC car to 5.48sec.

    Also running with SE piston and liners.

  6. Yes Glyn you are right i only have the standard Dump valve on the engine.

    I have driven cars with BOV's and the Whoosh at slow speeds is annoying (to me) at low revs and sounds like the no 10 buss coming down the road.

    I am running 10 Psi boost and the standard lotus Dump valve works perfectly.

    At low to medium throttle the over boost situation is controlled and there is no whooosh, however when really going for it the whoooosh is present for a very short period between gear changes.

    Now its only an opinion but the LOTUS dump valve releases just enough pressure to take the over boost pressure off the turbine blades and shuts again when pressure equalises to the set boost thus reducing the shock loading on the blades by keeping them under a relatively constant pressure. As throttle is opened then boost is already in the plenum thus no lag.

    Now a BOV releases ALL the pressure to atmosphere thus unloading the compressor blades. the stored inertia in the blades must then speed up the rotor to above or close to it the designed maximum rpm. when the throttle is opened the BOV shuts thus applying full boost back to the turbine blades Result high shock loading on the blades. I have seen turbine shafts snap with BOVs Fitted.

    I know my argument has faults, but, under such light boost as 10 PSI i am pretty sure that the arguments are academic. It all comes down to whooosh or not to whooosh.

    I would take the vacuum feed off the grub screw in the rear Carb manifold if i was fitting one.

  7. The SE pistons are forged with a chrome plating on the top which is more durable than the standard Ali. however the cylinder head still remains Ali and can not take too muck Knock (detonation). Something to do with the shock wave removing the Gas cusion between the surface of the cylinder head and the hot explosion.(only what i have read)

    The onset of Knock can be due to a number of issues including

    Ignition timing

    Cylinder head temperature

    Spark plug type/ Temp

    Boost Presure (excessive)

    Charge temperature

    Compression ratio (too high)

    Octane rating of fuel

    Etc. Etc

    So fishy the exact temerature that knock happens depends on a number of variables and can not be given, The temerature is more of a guide and if you can compare pre Charge cooler Temp with post Charge cooler Temp you can at least have a guide to how well your Charge cooler is working.

    There is some were in my pile of books some sort of Scientific explination that gives temperatures, from memory i think this is in the region of 90 deg C but i will try and dig it out for you and post the info.

  8. I fitted a chargecooler to mine, and I didn't fit any earth straps to it.

    So far, 5 years later, I've not had any problems.

    I think Lotus just earth everything in site, although there is no reason to earth the chargecooler anyway. It's not like some huge static buildup is going to kill you or anything.

    Having said that, the lotus air temp sensor may need to earth through the chargecooler. Stupid if it soes.


    The earth strap is there to remove the electrical charge in the coolent, if this is not done it will slowly eat the core of your chargecooler!!!(works on the same principal as a battery)

    This is the same reason why it is recommended to replace your engine coolent in the service intervals!

  9. Hi Simon

    I have always wanted to put a G body on an SE.

    Go for it if the price is right, but the residual will probably not be as good.

    Just for info the picture of the engine cover is not of a good standard and probably reflects the rest of the conversion.

    This is the picture of my newly finished charge cooler conversion i hope this will give you a good comparison of what is possible.

    Sorry not enough space for good pic check out my garage for a better quality image.


  10. I've had to replace piston and liners twice and belive me it is far easier with the engine out. Once the linear have been reinstalled the "NIB" (how far the linear protrudes from the block needs to be measured) if this is not correct (dirt on the sealing faces or a nick in the block when removing the linear) Then you will be replacing the head gasket inthe not too distant future.

    The engine can be removed in a morning complete with gear box. Its not that difficult and if you don't want to cause yourself more trouble it is the only way!!!!!!

  11. Thanks

    I am based in portsmouth, I will be phoning around this week to see if anynoe can do it!

    I have heard that screens are a bit difficult to get hold of and that the fitters have a few problems with the interior trim. (not sure if this is true).

    I am not too worried about the chrome trim, thinking about changing it for the Stevens black trim (no other chrome on the car) Does anyone know if it fits?

    On a plus note I got the last piece of the chargecooler jigsaw today so quite happy. Now I just have to find the time!!!.


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