Newbie question

[Andy wright]

35 minutes ago, DeanB said:

Andy when I had my suspension rebuilt for fast road and trackday use I specced OE rubber bushes. There is no need to go stiffer, it certainly wouldn't be worth the extra NVH.

I would recommend Nitron NTR shocks but have Nitron supply them with softer springs than the ones they normally supply if you are doing only/mostly road miles - the ones I have are too stiff for bumpy roads. They are a great quality damper though and Nitron are very helpful.

Thanks.o.e bushes it is when I start that job. Nitrons are heading towards the top of my list so thank you for the spring rate info. I will do a few wheel frequency calcs  to see , in theory , what Lotus did with the o.e springs. My guess is that they were close to 2Hz as standard but that’s just a guess at the moment. Certainly for mostly road use, which is what mine will be in the main, living with stiff springs for the sake of a couple of track days per year is the wrong compromise in my view . 

[DeanB]

I think, from searching seloc techwiki, that the standard OEM spring rates for s2 Rover are 200 front and 285 rear. 

The Nitron NTRs I have are 400 front and 475 rear, so you see my point.

I'm thinking of maybe getting some 300 front 425 rear. When I get round to it I'll call Nitron and ask if the existing valving would suit but it is, of course, adjustable, so I could probably find a setting that works for me. I like a firmly damped car, just not rock-hard springs. Plus I have a thicker arb.

D

[Andy wright]

17 minutes ago, DeanB said:

I think, from searching seloc techwiki, that the standard OEM spring rates for s2 Rover are 200 front and 285 rear. 

The Nitron NTRs I have are 400 front and 475 rear, so you see my point.

I'm thinking of maybe getting some 300 front 425 rear. When I get round to it I'll call Nitron and ask if the existing valving would suit but it is, of course, adjustable, so I could probably find a setting that works for me. I like a firmly damped car, just not rock-hard springs. Plus I have a thicker arb.

D

Thank you. Very helpful. 

3 hours ago, DeanB said:

Andy when I had my suspension rebuilt for fast road and trackday use I specced OE rubber bushes. There is no need to go stiffer, it certainly wouldn't be worth the extra NVH.

I would recommend Nitron NTR shocks but have Nitron supply them with softer springs than the ones they normally supply if you are doing only/mostly road miles - the ones I have are too stiff for bumpy roads. They are a great quality damper though and Nitron are very helpful.

Thanks.o.e bushes it is when I start that job. Nitrons are heading towards the top of my list so thank you for the spring rate info. I will do a few wheel frequency calcs  to see , in theory , what Lotus did with the o.e springs. My guess is that they were close to 2Hz as standard but that’s just a guess at the moment. Certainly for mostly road use, which is what mine will be in the main, living with stiff springs for the sake of a couple of track days per year is the wrong compromise in my view . 

[Andy wright]

Boring bit. I did a few rough wheel frequency calculations using data from here and from the Lotus Manual.I assumed a front axle weight of 342kg and a rear of 534kg. I then assumed that the unsprung weight at each corner was 20kg( that may be a slight under estimate ) and that the Orem spring rates were 200lb/in at the front and 285lb/in at the rear ( converted to N/mm ) . Then with motion ratios of 0.7 at the front and 0.718 at the rear , that gives an almost identical wheel frequency front and rear of 1.7hz . First thing to note is that the front and rear frequencies are almost identical.I am pretty sure Lotus did that to keep the car feeling balanced . Next point is that these frequencies , whilst higher than most ‘ordinary ‘ Road cars , are not overly high, and so I can see why companies who offer ‘ fast road and track day’ suspension up the spring rates . I will run off and do the calcs for the Nitron 400 and 475 and see what they give . 

[Andy wright]

And they are 2.4 for the front and 2.1 rear. I have never driven a lotus with Nitrons so I have no idea how good the damping is, but at those wheel frequencies , they will need to be mighty to control suspension on poor road surfaces. My Golf ran Moton 2-way dampers ( all £5k worth ) and I had wheel frequencies of 2.0 and 2.1 . Wonderful on track but on poor road surfaces it was best not to rush ! ( although it was rose jointed throughout ) 

[DeanB]

Interesting even though I know nothing about wheel frequencies!  Can you recommend where I might find a good explanation online?

I have added a photo of my corner weights with me aboard and about 10 litres of fuel.

 

[Andy wright]

Oh. Lighter than I thought. S1 or S2 ? For more detail, try ‘DRTUNED racing for spring rates and suspension frequencies . It’s not an exact science, more ‘ rule of thumb’ based on lots of empirical data over long periods of time. But it’s interesting. One thing is for sure. If one selects a spring rate that gives a wheel frequency of , say 2.8hz, on a public road the ride will be just about intolerable . 

[Andy wright]

Just answered my own question. S2 K series. And you have about 9-10 kg of fuel and X kg of you ( where 60< X<90) so your Elise is no more than 750kg. That is very light. 

[Andy wright]

And after all this talk of suspension, back to the seats and door cards . The cream interior has gone to a new home . £65 of eBay black doorcards arrived on Sunday and after a little tlc look like this . They are not absolutely perfect but pretty good: undamaged and almost without marks or scratches. 

[DeanB]

2 hours ago, Andy wright said:

Just answered my own question. S2 K series. And you have about 9-10 kg of fuel and X kg of you ( where 60< X<90) so your Elise is no more than 750kg. That is very light. 

I think it was 746kg with that bit of fuel in but no roof on or stowed.

[Andy wright]

Right. So you are 71kg. 😀😀😀😀

[Andy wright]

Flippant comments aside. That means that the lotus o.e spring rates were absolutely on the money for that weight. I have access to corner scales so I will  be interested to see what my 1ZZ powered S2 with me plus hardtop weigh in at .

And the seats saga. I saw a pair of B5 Tillets on Facebook but on enquiry found they were sold. Sob. So went ahead and ordered a pair of Corbeau LE seats with the Lotus logo sewn  in to the headrest. Then yesterday said Tillets popped back up again , so if anyone wants a brand new pair of Corbeau LE seats still in their boxes ( they haven’t arrived yet ) ……..😀

[DeanB]

16 hours ago, Andy wright said:

Right. So you are 71kg. 😀😀😀😀

I was! 

I might be a bit more now I have been hitting the gym!

D

[Andy wright]

On 24/11/2024 at 20:22, DeanB said:

I think, from searching seloc techwiki, that the standard OEM spring rates for s2 Rover are 200 front and 285 rear. 

The Nitron NTRs I have are 400 front and 475 rear, so you see my point.

I'm thinking of maybe getting some 300 front 425 rear. When I get round to it I'll call Nitron and ask if the existing valving would suit but it is, of course, adjustable, so I could probably find a setting that works for me. I like a firmly damped car, just not rock-hard springs. Plus I have a thicker arb.

D

I have been helping my friend today doing some prep on his Series2 K series race car( At Oulton  park next week for testing and Donnington racing at the weekend . ) His car is down at 700kg and has some serious downforce . Damping is Ohlins TTX and springs are 456lb/in front and 630lb/in at the rear ( the rear wing can generate a lot of downforce at 100mph ) . But this is a full  race car , so a road car with 400 front and 475 rear must be really, err, firm . My Golf R32 with 2 way Moton damping and 1510 kg had 470 up front and 340 at the rear . That was firm . Anyway, plenty of time for more research before hitting any ‘ buy ‘ buttons .

[Oakman]

6 hours ago, DeanB said:

I was! 

I might be a bit more now I have been hitting the gym!

D

Are you sure that’s hitting the Gym, Dean   Or could it be hitting the breakfasts at Hassop Station cafe ?  😉

Paul 

PS. Kettle most definitely calling the  pot black. 

Edited November 26, 2024 by Oakman