Lotus Elan

Use of Tetra boost

PostPost by: JasonJ » Wed Apr 03, 2024 7:19 am

Gents

I’m in the middle of getting some head work done, which was originally new 360 cams, bearings and followers, due to wear we are now looking at inlet and exhaust valves , valve guides, seats and a skim.

My question is in the past I have used Tetra boost, should I continue to use this once head has been fitted with new components And if possible can give pros and cons of using this Additive

All new valve train components are standard parts from QED.

Regards
Jason
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PostPost by: mark030358 » Wed Apr 03, 2024 8:12 am

Hi,
I never have on my engine and if they do the seats it’s no issue anyway.

Cheers
Mark
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PostPost by: JasonJ » Wed Apr 03, 2024 8:31 am

Thanks Mark,

Yes the seats are getting done.
I was considering using a slightly weaker mixture, I have 3 new bottles and in typical Scotsman fashion I never wanted them to go to waste.

Jason
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PostPost by: bitsobrits » Thu Apr 04, 2024 12:51 pm

Pro-it may help reduce pinking if you are running too much timing advance.

Con-it's simply not required, so it's not money well spent. Lotus used hardened stainless seats from new so no benefit there. And the twin cam is not prone to pinking if your distributor advance is functioning to spec, assuming high octane (pump) fuel.
Steve

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Elan S3 1967 FHC pre airflow

Formerly:
Elan S1 1964
Elan S3 1966 FHC pre airflow
Elan S3 1967 FHC airflow
Elan S4 1969 FHC
Europa S2 1970
Esprit S2 1979
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PostPost by: JasonJ » Thu Apr 04, 2024 2:57 pm

IMG_0211.jpeg and
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PostPost by: 512BB » Thu Apr 04, 2024 5:40 pm

'Lotus used hardened stainless seats from new'

Not so. The valve seats on all twin cam engines were hard, but they were not stainless.

A popular www. myth when unleaded petrol was introduced was, 'you must get your valve seats changed to hardened, as the ones that are made of butter wont stand unleaded'.

On all the heads that I have had appart and rebuilt, not one showed valve seat recession due to being run on unleaded. Recession due to the seats being cut to deep, or to often maybe, but not because of the fuel used.

Don't believe the hype.

Leslie
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PostPost by: JasonJ » Thu Apr 04, 2024 6:49 pm

The only reason I started using Tetraboost if I remember correctly is from reading this, it’s good to hear people’s experiences.

I will probably continue to use this just to combat the ethanol content because I would not put it past Oil and Gas Operators tweaking a % or 2 in there favour, I may go for a weaker TB mix as stated. But I shall remain open minded on the subject. :D
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PostPost by: sng » Fri Apr 05, 2024 9:17 am

Often when I read discussions on fuel there is no mention of which carburettors the engine is equipped with. My assumption is that Webers / Dellorto's behave differently to Strombergs.

My engine has Strombergs and I find that using Valvemaster Plus with 99 RON fuel makes the engine run smoother which must be due to the octane boost. I realise any octane boost is very small but for my engine it makes a big enough difference to be cost effective. I do not use it to save the valve seats which have been replaced, I am sure there are better octane boosters but this works for me. Like lots of owners my head has been skimmed so I have no idea what the current compression ratio is. The engine does not noticeably pink with the additive which I believe is more of a problem on Stromberg engines and yes my timing is set up correctly. I had always assumed the Stromberg engine was designed to run on 5 star fuel which would have been more available when the car was produced, I am sure people on this forum can confirm on squash that rumour.

The diaphragms on the Strombergs would be eaten away by ethanol but it's probably cheaper to buy new ones regularly than pay for additives. I am in the process of replacing all fuel lines with ethanol resistant ones, just the pipe from the tank to the fuel pump left, purchased but not fitted. Again doing this must be much cheaper than paying for additives and I know many other people on this forum have done the same.

I am very interested to hear other peoples experience of using additives on Stromberg engines as well as Weber's / Dellorto's and happy to be corrected on any of my assumptions.
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