S4s rolling restoration project

[tomcattom]

If there is interest in me running one I can speak to my fabricator about the cost of making a jig and producing a batch @Sparky.

[jonwat]

On 23/07/2022 at 18:53, tomcattom said:

it's more the flat spot low down in the rev range

Sounds like the infamous S4s 3K stumble

[tomcattom]

Pipework all welded and ready to go on the car.

 

I did ask about grinding the welds down afterwards but the fabricator advised against it because the tubing I used is quite thin and it might weaken the joins if we did. Given there might be interest in a group buy, having the welds on show helps me template this one to make more if required.

[Barrykearley]

He’s absolutely right. Looks just fine

[Sparky]

I do think this has potential as a group buy.  A lot of hoses out there that are close to end of life, and what's currently available as a replacement is poor IMO.

[Gjk]

I’d be interested in a group buy, if the pipe will fit an se as well.

[tomcattom]

My pipe has cost me a shade under £150 all in to make, that includes silicone reducers, jubillee clips and the cost of the welding.

Out of curiosity I just checked online and the OE part appears to still be available from Lotus but it costs £212.72+VAT 😮

https://www.bellandcolvill.co.uk/product?qs=1&MAK=1&MDL=15&TBL=1555&SMA=0&SMO=0&ST=&SC=0&PBID=44099

Looks like there could be a market for a group buy potentially then... 🤔

[tomcattom]

2 hours ago, Gjk said:

I’d be interested in a group buy, if the pipe will fit an se as well.

If it has the chargecooler, then it looks like it should fit from a quick glance at the parts list. Just not sure whether the turbo compressor inlet is a different size and might require a different size of silicone reducer. That statement would apply to any model that isn't an S4s I guess. I don't know if the turbo compressor inlet differed greatly, if at all, between models.

[Gjk]

I’ve just checked the parts catalogue for the se and s4/S4s and the air box to turbo hose is the same part number in both manuals (F907E1089F) so it should fit no problem.

[jonwat]

2 hours ago, tomcattom said:

I just checked online and the OE part appears to still be available from Lotus but it costs £212.72+VAT

Or £109.38 plus delivery from SJSportscars 

[Giniw]

You beat me to it @jonwat.

Indeed, £100 is expensive for what it is already, but 200+ is pretty ridiculous imo.

Edited April 27, 2023 by Giniw

[Barrykearley]

Just be aware the stock part is flexible. This solution isn’t. 
If you have a alunox manifold the alignment could be an issue. 

[Sparky]

The SJ alternative is longer than it needs to be and incredibly inflexible.  It almost pushes the airbox off its (admittedly poor) mountings.

For X180-on, the fit should be standard for all but Sport 300 which has a larger turbo outlet.

Might improve laminar flow too!

And then there's the G-car option...

[jonwat]

1 hour ago, Sparky said:

The SJ alternative is longer than it needs to be and incredibly inflexible

SJ are stating that it's a genuine Lotus part?

[Sparky]

Given I've fitted several from there, I'd disagree.  However, maybe they were updated.  Dreadful IMO.

[tomcattom]

Applied a couple of strategically placed pieces of self adhesive foam to the underside of the pipe where it gets particularly close to the bell housing and the clutch master cylinder to prevent contact damage between either and also to prevent any annoying rattles when driving.

 

Pipe all fitted and secured with fresh jubillee clips

 

Boot floor should go back in over the weekend and then its good to drive again

[Chillidoggy]

Nice job!

If there's any contact though, stick-on foam will last about 5 minutes. Rubber insertion would be a better choice, it's much more robust. 

[drdoom]

35 minutes ago, Chillidoggy said:

Nice job!

If there's any contact though, stick-on foam will last about 5 minutes. Rubber insertion would be a better choice, it's much more robust. 

x 2! Silicone rubber will tolerate massive heat.

[tomcattom]

Its not actually in contact, its more a preventative measure incase, through movement in the engine bay, that they end up touching.

The rubber was all I had to hand in the garage at the time. It's actually some left over closed cell neoprene stuff from one of the other jobs on the car. I'll see how it holds up if there is contact and I can improve upon the material choice later if needed, or the pipe shape itself. The pipe is still somewhat of a prototype at this stage.

[Giniw]

Talking about engine movement, is there enough slack to accommodate the engine displacement relative to the air box in the side wall?

[tomcattom]

There's only one way I'll find out @Giniw

[Gjk]

Just a thought, what about doing it the other way round? By that I mean having the reducer mounted to the air filter  outlet and a smaller diameter tube to run down to the turbo inlet.

[tomcattom]

I'm no fluid dynamicist, but as I understand it from my research, you want the maximum size pipe to the compressor inlet and reduce it down as close to the turbo as possible @Gjk, but I don't know the exact physics as to why.

[drdoom]

Perhaps instead it's on the exhaust turbine side where one seeks to expand the pipe promptly, old reference cited here from a book authored by Hugh McGinness. (Apology if name misspelled, my library is in temporary storage.) The theory was that spiralling flow exiting the turbine should be made laminar and straight as quickly as possible. Search for discussion on contouring the inlet side flow over in the Stevens threads, per either @CarBuff or @MrDangerUS.

Cheers

McInness IIRC

[Gjk]

It was just a thought.

it has been far too many years since I studied fluid and thermo dynamics for me to remember anything of any importance, so apologies for the stab in the dark.