S4 Duratec Project *The finishing Touch*

[Spyder fan]

Mark,
I was going from the Raceline specification in their brochure http://cv-8.com/Build/duratecbrochure2005.pdf pages 5 & 6 list the power outputs claimed by them and the mods required to achieve them. They say that the power claims are conservative and that 220bhp is often achieved from the 2nd line options, after this as you say it gets expensive, but prices are coming down now that this seems to be one of the first choice engines for kits and specials like mine.

I think that I will be more than happy with 180 - 190 bhp, the torque that you mention will make it an easy car to drive on the road and will give loads of fun on the track.

For tyres I'm going to try the Yoko C Drive 2, these have superseded the old C drives and they claim better traction, if I find them disappointing I will fit the AO48's that I have fitted to my +2 track wheels. I looked at the new S drive tyres but was a bit worried about the 55 profile on a 14inch rim, I will let you be the guinea pig on that one

Stripes, Stripes, Stripes I really don't know what wording is tasteful other than ELAN or ELAN SPRINT. ELAN is being honest and ELAN SPRINT will upset a few people, but no more than all the other S4's that have had this sort of livery applied either in period or long after the event. ELAN DURATEC will only mean something to enthusiasts and anoraks. I like ELAN SPORT, but thats a bit of a misnomer as why would I want to claim to have a sports version of a sportscar Perhaps this is one area of Lotus design that can't be improved on.

[collins_dan]

Mark, Are the 185/55/14s for an S4? What did you use for wheels? I was thinking about that size on minilites for my S4. Thanks, Dan

[garyeanderson]

Solid gold stripes on the sides and Seven lonely letters across the rear!

Enough Said!

Gary

[Spyder fan]

Mark, Are the 185/55/14s for an S4? What did you use for wheels? I was thinking about that size on minilites for my S4. Thanks, Dan

Dan,
Mark is building an S4 Zetec and is using 14" minilites, the tyres will fit obviously but there may be undergearing and speedo reading problems as well as slightly reduced ground clearance with the 55 profile rather than the recommended 60 profile on the 14" wheels. That's why I said I would let him be the Guinea Pig for this.

Regards

[Spyder fan]

Solid gold stripes on the sides and Seven lonely letters across the rear!

Enough Said!

Gary

I like it , but I already will have 5 lonely letters that spell L O T U S on the boot lid and the rectangular UK license plate goes beneath that.

I'm pretty much set on going for gold stripes with ELAN SPRINT and then making 2 no plates to go on the wings that say LOTUS ELAN Duratec R

duratec-badge.jpg (10.13 KiB) Viewed 1883 times

instead of the LOTUS ELAN Sprint

sprint-badge.jpg (8.39 KiB) Viewed 1883 times

[collins_dan]

Alan, Good point on the rolling radius differences. I currently have Toyo RA1s on my S4, which are 185/60/R13s. They are great for autocross, but I intend to buy a set 14" minilites with tires that have a rolling radius closer to the original tires for everyday. Thanks. Cheers, Dan

[Mark B]

Dan/ Alan,

Yes they're on minilites (spyder supplied) as Alan said on an S4, for various reasons I went for 55 profile- 185's don't always fit every car, and if they don't catch when it's stood still they may catch when it's moving -especially cornering, so with a slightly lower sidewall there's less sidewall deflection and hopefully(!) less chance of them catching the body. I personally prefer the look of the slightly lower profile too.

185/55 versus 185/60 is only 2.29 inches less in circumference and 0.73 inches less diameter so the ride height difference is only about 9mm between the two, which fair enough is lower, but not massively. Although I may later regret saying that if I've just ripped the exhaust off on something!

To put it in perspective a 155/70/13 original size tyre is 67.67 inches circumference, a 185/60/14 is 71.44 inches so with the original speedo on spyder wheels/tyres it'll be miles out anyway.
With the speedo I'm using vdo electronic instruments so I can easily re calibrate it to read correctly, I'll try it first with my sat nav & see how far out it is.

I also wanted a "proper" high performance tyre, and although you get a better choice with 14" diameter there's still not masses without going for a trackday tyre, the S drives are the best ones I've found for me tbh...

Cheers,
Mark.

[GrUmPyBoDgEr]

Mark,
would it be possible to post a photo of those wheels with the 185/55x14 tyres fitted, possibly on the car?
May be a usable solution for my S4

Cheers
John

[collins_dan]

David posted the below, which had me thinking that 185/60-14s could be a good option, but your 55 option could be close as well. Not sure what the rev/mile would be for it.

155/80-13 tire is 912 rev/mile
165/80-13 tire is 887 rev/mile - a 2.82% difference from 155-13 (I upgraded from 155-13 w 5.5 wheels at first chance)
165/70-13 tire is 942 rev/mile - 3.29% fast over 155-13
175/70-13 tire is 917 rev/mile - 0.57% fast over 155-13
185/70-13 tire is 893 rev/mile - 2.07% slow over 155-13, 0.69% fast over 165-13 (I ran this for years)
185/60-13 tire is 956 rev/mile - 4.77% fast over 155-13, 7.72% fast over 165-13
165/70-14 tire is 899 rev/mile - 1.37% slow over 155-13, 1.41% fast over 165-13
165/65-14 tire is 925 rev/mile - 1.48% fast over 155-13, 4.34% fast over 165-13
175/70-14 tire is 880 rev/mile - 3.51% slow over 155-13, 0.79% slow over 165-13
175/65-14 tire is 905 rev/mile - 0.76% slow over 155-13, 2.04% fast over 165-13
185/60-14 tire is 915 rev/mile - 0.29% slow over 155-13, 3.12% slow over 165-13 (This is what Spyder does)
185/65-14 tire is 884 rev/mile - 3.12% slow over 155-13, 0.39% slow over 165-13

So if you are replacing 155-13 tires, try to get close to 912, if replacing 165-13 get close to 887.

There is a downloadable spreadsheet at elan-f15/updated-spreadsheets-t18445.html that lets you see all this and to get the best transmission drive gear or speedometer gear combination.

David
1968 36/7988

[Mark B]

John,

No problem but the body is off the chassis at the moment, & I'm off to london for a couple of days with work but will take a pic when I get back. The other point worth noting about the s drives is that they're a very square shouldered tyre, whereas most "bulge out" on the sidewall, so the overall width of the s drives is pretty much constant from the sidewall to the tread.

Dan,
Thanks for the info, it may help me putting the correct figures into my speedo to calibrate it. To be honest though I was mostly concerned about having a decent cruising speed/revs. As long as the speedo reads under rather than over at least you've less chance of being caught speeding!

Alan,
Raceline are very good & as I said before I really rate them and their products but of the people I've met with raceline kits most have produced 10hp or so down on average from the claims. They're no different in this respect than dunnell, sbd etc because they're all trying to sell their products & bhp figures help sell engines! There's only a minority of tuners that I've come across that are truly conservative/realistic with expected hp figures. Scholar engines are one of the few that spring to mind. It'll be a quick little car whatever state of tune it's in and should be a hoot to drive, I look forward to seeing it at donnington.

Cheers,
Mark.

[gordont]

this download does not work for me, does anyone know the correct link?
elan-f15/ updated-spreadsheets-t18445.html

[ardee_selby]

Gordon,

Link to page referred to: (elan-f15/updated-spreadsheets-t18445.html) which contains a link to the file...

Or, direct link to file is:

download/file.php?id=6626

Cheers - rd

[collins_dan]

I have never had any success opening that file, which is why I sent the relevant information extracted from it. I think it might be zipped. If someone could save it somewhere on the site as a simple excel file, I would love to be able to open and use it. Thanks. Dan

[ardee_selby]

Dan,

Explanation of what to do was in given in the related thread:

[i]"As before, the spreadsheet is too large to upload directly to LotusElan.net. So it is compressed (ZIPped). However, LotusElan.net does not allow .ZIP files, so the files is renamed to a .XLS extension. After you download the file, rename it back to its .ZIP extension, then extract the .XLS file."[/i

Cheers - rd

[gordont]

bugger, I still can't get it to work - when I open it it comes up all corrupted...