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Esprit Turbo project car - part3 - the further continuation - Page 251 - Esprit 'Project & Restoration' Room - The Lotus Forums #ForTheOwners Jump to content


Esprit Turbo project car - part3 - the further continuation


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Hi Fabian - In addition to compression, an HC uses larger inlet tracts, different inlet manifold and increased boost.   Additionally, you cannot directly compare DHLA40's to the HC's DHLA45's - as the 45's are a different design with an additional 'Powerjet' circuit and actually runs a smaller choke size than the LC models!  (my guess is they only went to a 45 body to take advantage of the power jet) - To avoid running lean at high speed.

When I was setting mine up, which does run an HC head, elevated compression and increased boost, I experimented with larger idle jet holders in DHLA40's and found them unsatisfactory as they immediately 'kicked' too rich as soon as the throttle was touched from idle, before transition occured.

I get pretty good transition & power off a 43 idle jet with standard holders.  I also run larger main jets and pump jet calibration based on an HC, which has a slightly elevated volume.

NB - What do your plugs look like, now you have a some miles on the engine?

  

 

 

 

 

 

 

 

 

 

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Thanks Steve, really interesting, because  of the number of variables maybe a rolling road is really the way ahead. Not sure whether I will even bother with the new jets and holders, now I know what you have already discovered. I knew the carbs were a different model, but didn’t know about an extra circuit. I also believe the HC has vacuum advance. The engine runs great beyond 3000 rpm, so I was thinking the mainjet, emulsion and air correctors didn’t need adjustment? Can you remember what sizes you used? 

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Fabian, please don't presume that the feel of the engine adequately sums up whether it's correctly tuned. With forced aspiration engines it is quite imperative that lean settings are avoided under boost, as is excess spark advance. Don't lean on it much before the pro's have sorted it out. Afterwards you may fiddle with driveability concerns once the base fuel and spark settings are sound. Cracked pistons and/or blown head gaskets are no fun. 

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10 hours ago, Lotusfab said:

Yep, I need to get it on a rolling road ASAP. I have an expert taking a look at  it next week. Hopefully he can steer me in the right direction. 

He will if he's at all worth doing business with. 😑

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13 hours ago, Andyww said:

I believe the vac advance on the HC is not used when the engine is warm, its cut in/out by a temperature controlled valve.

Thats interesting. I haven't heard of a vacuum advance being inhibited by temperature before. 

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Looking at section EMC in the book, I think there is more to it than that.   The vacuum unit is double acting, with one side permanently connected to plenum pressure and the otherside diverted to a different source depending on temperature. 

Below 60 degrees it applies max vacuum/max advance by connecting the the vacuum unit directly to the vacuum pump line.  Above 60 degrees it uses a thermal valve to divert the vaccum unit to a 'throttle edge drilling' which presumably must give a differential between the opposing plenum pressure connection.   So I assume its doing something akin to traditional vacuum advance above 60 degrees.

 

 

 

 

 

 

 

 

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36 minutes ago, Lotusfab said:

The solution to tuning these car is probably to fit a Lambda sensor in the exhaust and a gauge.

When I owned my Excel I fitted fuel injection to it and also fitted a mixture gauge to the dash, replacing the voltmeter. The gauge turned out to be quite useless for tuning because the mixture on a properly tuned car varies hugely, its never at the optimum, nor supposed to be, for best performance without engine damage.

What I should have done is had it tuned on a rolling road but at that time I had very little money and what I had I spent all on the EFI 😞 It was a project I should never have started at that time.

Rolling road is the way to go but can be a very long and expensive process and do people still have stocks of different Dellorto jets?

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  • 2 weeks later...
2 hours ago, Lotusfab said:

I was dismayed to find one of my new rear Vredstein tyres got a puncture due to a pothole. Unfortunately it was too close to the sidewall to repair.

Take pictures & send them to the council demanding compensation for your loss. :thumbup:

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Cheers,

John W

http://jonwatkins.co.uk

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Ok rear nearly done! It took one 6 mm shim plate on the rear left to reduce the toe in to 1 mm. 
The rear left camber needs to be checked again now the shim plate is installed.

The front caster I measured as 1 degree and 45 minutes. So will install a 1.5 mm shim behind the anti roll bar and measure again, it needs to be 3 degrees. This is time consuming, but pretty easy. Should have it sorted in the next few days. I have been working on a Landrover Discovery in between. The fuel burning heater was smoking. I think I have fixed it and my webasto diagnostic software shows no faults. So no more distractions!

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  • Gold FFM

Why didn't you just put your car on one of the Hunter laser-alignment machines at KwikFit and have it checked? Last time I had mine done it was about £50. In fact, it would be worth checking it now so you can see how accurate you were with your calculations.

Margate Exotics.

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5 hours ago, Lotusfab said:

I realised I havn’t lubricated the Trunnions since I built it. They used EP90 oil. I have bleed nipples fitted, so have to buy a second grease gun and fill it will EP90. Pretty important to keep these well lubricated. Maintenance is very imported on these cars if you want them to be reliable.

It should have bolts fitted not nipples, you can remove them & then push an oil can spout against the hole then pump away until fresh, clean oil comes from under the seal. Wouldn't have mentioned replacing the nipples except I know what a stickler your for details. 😃

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Cheers,

John W

http://jonwatkins.co.uk

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13 minutes ago, jonwat said:

It should have bolts fitted not nipples, you can remove them & then push an oil can spout against the hole then pump away until fresh, clean oil comes from under the seal. Wouldn't have mentioned replacing the nipples except I know what a stickler your for details. 😃

Book method here but if an oil can will do it that sounds fine.:
 

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59 minutes ago, Chillidoggy said:

Why didn't you just put your car on one of the Hunter laser-alignment machines at KwikFit and have it checked? Last time I had mine done it was about £50. In fact, it would be worth checking it now so you can see how accurate you were with your calculations.

I did that with the S1. The main stream companies know nothing about aligning an Esprit chassis. I got them to measure it and then took it away and shimmed it myself and brought it back for a final check.

I had an align check done on this, but the same problem they haven't got a clue what they are doing. I trust my own readings more than theirs. Plus I don’t damage the wheels buy strapping on laser targets. 
In fact Kwik fit damaged my Land rover chassis and told me it had to be scrapped! I told them I have just rebuilt the entire front end and  they have damaged it by not loosening the chassis bolts prior adjustment- I heard the guy swear as he flattened off the chassis lug with a breaker bar and then he disappeared! I suggested they read the Landrover alignment guide and their alignment screen before they attempt to adjust the alignment on something they don’t understand. In the end I told them to get it off the ramp and never went there again.  I bought and ID tool interface and got a company to adjust it under my supervision, after I had put into tight tolerance mode and calibrated the steering angle. 
I am no longer convinced electronic alignment is any better than the old fashioned ways. Lotus aligned it using parallel bars in the factory. Track cars and F1 still use the old methods. Its a personal choice, but I think because I can spend unlimited time on it in the end my result will be just as good or better. 

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