Sag spec/Stiffer rear springs

[hollowpockets]

After melting my tyres to the rear inner arches on the ring iv decided the rear shocks (nitrons) need stiffer springs, does anyone know the weight of standard nitron springs? i was told to just try 50lb heavier... The fronts behave perfectly, i don't want to change them but worry it might leave the car unbalanced just changing the rears.

Any experiences/help/comments welcome...

Graham

[T450t]

I think the original rear springs are around 350lb with the fronts being 400lb. I am running 725lb on the front and 650lb on the rears now with Nitrons. Its very difficult to get a good balance its either track biased or road biased. You will need to choose which direction you are heading. The design of the rear arches means you cant go into the middle ground.

Some folk are running even higher !

[tail slide]

T450t said:

I think the original rear springs are around 350lb with the fronts being 400lb. I am running 725lb on the front and 650lb on the rears now with Nitrons. Its very difficult to get a good balance its either track biased or road biased. You will need to choose which direction you are heading. The design of the rear arches means you cant go into the middle ground.

Some folk are running even higher !

That's certainly a set up for fastest tracks IMO, 650 at rear is unexpectedly high as they're inclined at less of an angle than front? But agree rear arches are the issue - to allow enough rear travel on track without putting rear too high or stiff I cut out & re-glassed outer section of inner arches which foul otherwise with 255 R888's. But not the easiest job, esp as there is wiring sitting inside each arch where you want to cut

I'm running 500/400 with Nitron 3-ways now, didn't personally find I needed it any firmer even at Goodwood last weekend, no swaying through the 125mph kink, firm but not harsh on road with good traction (after re-setting dampers)

Edited by tail slide on Sunday 6th July 09:26

[T450t]

tail slide said:

T450t said:

I think the original rear springs are around 350lb with the fronts being 400lb. I am running 725lb on the front and 650lb on the rears now with Nitrons. Its very difficult to get a good balance its either track biased or road biased. You will need to choose which direction you are heading. The design of the rear arches means you cant go into the middle ground.

Some folk are running even higher !

That's certainly a set up for fastest tracks IMO, 650 at rear is unexpectedly high as they're inclined at less of an angle than front? But agree rear arches are the issue - to allow enough rear travel on track without putting rear too high or stiff I cut out & re-glassed outer section of inner arches which foul otherwise with 255 R888's. But not the easiest job, esp as there is wiring sitting inside each arch where you want to cut

I'm running 500/400 with Nitron 3-ways now, didn't personally find I needed it any firmer even at Goodwood last weekend, no swaying through the 125mph kink, firm but not harsh on road with good traction (after re-setting dampers)

Edited by tail slide on Sunday 6th July 09:26

Paul, The suspension area is a very personal thing I think and one that if brave enough can spend lots of time twiddling till you get the right balance for you own personal needs. I'm not one that subscribes to the over the top technical jargon side to this area as I believe the best person to judge your set up is you/me.

With regards to the rear spring rates I find that on high compression tracks like Cadwell, Oulton, Brands etc I had to run the car quite high to stop tyre rub (more so if you were 2 up ) Since running at 650lb I have found that I can run the height so the wheel arch and tyre are very close without contact and by doing so has also stopped stepping around fast corners (copse etc) it now a much easier to control drift.

Everyone to there own I guess.

[Ab Shocks]

I would have a word with Nitron first because without a revalve or changing to 2 way shocks you will be limited to 450lb front and 375lb rear with standard valving.
That said, that would be a 50lb increase, which would be noticable.

This would not be enough for the serious trackday stars though imho and I reckon that 600lb front and 450lb rear is as far as I would go on a car I had to drive on mixed roads and track.

[tail slide]

T450t said:

Paul, The suspension area is a very personal thing I think and one that if brave enough can spend lots of time twiddling till you get the right balance for you own personal needs. I'm not one that subscribes to the over the top technical jargon side to this area as I believe the best person to judge your set up is you/me.

With regards to the rear spring rates I find that on high compression tracks like Cadwell, Oulton, Brands etc I had to run the car quite high to stop tyre rub (more so if you were 2 up ) Since running at 650lb I have found that I can run the height so the wheel arch and tyre are very close without contact and by doing so has also stopped stepping around fast corners (copse etc) it now a much easier to control drift.

Everyone to there own I guess.

Quite agree personal preference comes in Mark, for stiffness, preferred balance front to rear, preferred set up to corner neutrally on steady throttle or under acceleration etc etc. Any T350's rear is certainly more stable run fairly low no matter what the spring rates, and was first thing that Neill A advised me to do to avoid early tail-out moments regardless of acceleration!

Control is everything.

[trackcar]

650 rear is a ridiculously high figure, have you got any rear grip left at all? We're running less than that on our race T350 with MASSIVE rear aero and slicks! I would be very interested in whatever fundamental flaw you have in the rear of your car to make you need to use springs that stiff on a low aero road based chassis .. sounds to me like you're curing the symptom not the cause.

[tail slide]

trackcar said:

650 rear is a ridiculously high figure, have you got any rear grip left at all? We're running less than that on our race T350 with MASSIVE rear aero and slicks! I would be very interested in whatever fundamental flaw you have in the rear of your car to make you need to use springs that stiff on a low aero road based chassis .. sounds to me like you're curing the symptom not the cause.

Good to see Cliff's podium finishes mounting up!

It's the arches on our standard bodies, these tyres have especially wide shoulders - but I never had any clearance issues with v. slightly narrower 245 section R888's as long as it ran at 2deg neg camber, and no noticeable difference in grip.

Probably best answer for everyone is to stick with 245's, or maybe 255's for any other track tyre makes that have narrower shoulders.

[T450t]

trackcar said:

650 rear is a ridiculously high figure, have you got any rear grip left at all? We're running less than that on our race T350 with MASSIVE rear aero and slicks! I would be very interested in whatever fundamental flaw you have in the rear of your car to make you need to use springs that stiff on a low aero road based chassis .. sounds to me like you're curing the symptom not the cause.

Thanks for that Julian but after you telling me once ride makes no difference I think I will stick with my expert.

Thanks all the same

the Nitrons I have are more than capable so we have plenty to fiddle with and grip level is awsome.

If you think that's high Julian you ought to what some of the GT2;s are running and some of your competitors come to that.

[trackcar]

I know what a few of my competitors are running thanks, I help set them up and I don't think we're exactly struggling for corner speed in the T350 the chassis is sublime. If you like your car at 650 that's fine, it's just way stiffer than it needs to be in my opinion unless you have even more aero than we do?

PS remind me of the conversation where I said ride was of no importance? I'm pretty sure you must have misunderstood that conversation ..

Edited by trackcar on Sunday 6th July 16:24

[T450t]

trackcar said:

I know what a few of my competitors are running thanks, I help set them up and I don't think we're exactly struggling for corner speed in the T350 the chassis is sublime. If you like your car at 650 that's fine, it's just way stiffer than it needs to be in my opinion unless you have even more aero than we do?

PS remind me of the conversation where I said ride was of no importance? I'm pretty sure you must have misunderstood that conversation ..

Edited by trackcar on Sunday 6th July 16:24

Proof is in the pudding Julian and the T350 you help with is certainly proving its point and good luck with the rest of the season

Firstly Julian I did not ask your opinion

Secondly it was at cadwell 3 years ago when you had your S with you (I think it was an S) that was sitting 4 inches to high IMO. I asked why it was sitting so high and your reply was ride height has no importance on handling. Good job it rained that day or you may have been going home in an ambulance.

You have obviously been to night school since then.

The reason for my madness as you may think is its best to start from the top and work downwards from where you was. As going from the lowest to the highest settings highlights the difference rather than going up in increments which may not highlight the differences.



Like I said we should agree to disagree.

[trackcar]

You most certainly will have misheard / misunderstood that conversation then as ride height has dramatic influence on handling if altered in isolation, or it may have been that I said you can trim the handling after you've decided on a sensible ride height for your use of the car in which case the comment would be true. It might be that you can't get it as correct as you'd like (you never can anyway) but that doesn't mean to say 4 inches lower would be better either! (in fact it would be very very bad on my S .. read on ) .. I very much doubt my S was 4 inches too high, that's almost it's total wheel travel! I do run my S at a good height for road use though, as that is where it spends most of it's time and it's on-track performance is acceptable given its dual-role. I have driven my S on very many dry track days since of course and have yet to visit the armco, or indeed the inside of an ambulance .. but I thank you for your concern at my apparent death-wish regarding my own track transport (even though I didn't ask for your opinion ...)

You're right, you didn't ask for my advice, but I didn't want anyone else to read your comments and think that it was sensible to run those spring rates, so whilst the comment was as a direct result of your input on the thread you may of course choose to disregard my advice, as is your right of course.

Have you ever thought about entering a car into the Challenge? .. you would be made very welcome and it would be a chance for you to show just how good you actually are in real competition. We are always seeking new members to TVR racing so how about it? In the meantime if you see me at a track day please come over and introduce yourself, would be good to meet again the man behind the secretive profile.

Edited by trackcar on Sunday 6th July 17:35

[TVR_owner]

I'm starting off with 800 fronts and 400 rears on my racer. It's a little lighter than the T350 racer and different weight distribution I suspect - with an Essex V6 up front rather than a front mid engined alloy S6.

I see the comments previously on rear spring rates and wonder...is a stiffer rear anti roll bar not the place to start rather than such stiff springs.

ps..its a question, I dont know the answer.

[trackcar]

Hi John .. our T350R is still nose-heavy .. one of the downsides of running a long engine with a long crank and front-mounted rad and oil tank. However it is representative of what you can achieve with a T350 road based car and we like that

[tail slide]

hollowpockets said:

After melting my tyres to the rear inner arches on the ring iv decided the rear shocks (nitrons) need stiffer springs, does anyone know the weight of standard nitron springs? i was told to just try 50lb heavier... The fronts behave perfectly, i don't want to change them but worry it might leave the car unbalanced just changing the rears.

Any experiences/help/comments welcome...

Graham

A thought - is yours on original factory ride height? Several of us have noticed it looks rather low.

It was set too low at the factory after requests from some dealers who thought it looked better, then in late '04 all dealers were told to raise front & rear by about 15mm as that's where the suspension works best (with wishbones close to parellel with the ground) and normally allows enough travel to avoid wheelarch contact. I don't have exact settings though & mine's now non-standard.

[T450t]

You could change the anti roll bar bushes and drop link bushes to polyurethane which helps on stiffness. but don't take any notice of me I may kill somebody


Mark, the mystery man

[tail slide]

T450t said:

....but don't take any notice of me I may kill somebody

...only the Gt2 driver trying to keep up through the corners.

[TVR_owner]

Paul,
O/T. I had a discussion about Pork performance relative to TVR on Sunday. I hope to get my (standard) Porker out on track with Mark, possibly in September and it it should be an interesting comparison - despite Marks car being modded to death..........always assuming he's still alive in September

[T450t]

Trying to keep up with a Porsche built in a factory in Stuttgart Germany, against a TVR built in a shed in Blackpool England.

Not a chance Paul !

Whilst on the subject of anti roll bars, has anyone tried to get the ARB off and out of a SP6. Did TVR build the car round the ARB.

[hollowpockets]

tail slide said:

hollowpockets said:

After melting my tyres to the rear inner arches on the ring iv decided the rear shocks (nitrons) need stiffer springs, does anyone know the weight of standard nitron springs? i was told to just try 50lb heavier... The fronts behave perfectly, i don't want to change them but worry it might leave the car unbalanced just changing the rears.

Any experiences/help/comments welcome...

Graham

A thought - is yours on original factory ride height? Several of us have noticed it looks rather low.

It was set too low at the factory after requests from some dealers who thought it looked better, then in late '04 all dealers were told to raise front & rear by about 15mm as that's where the suspension works best (with wishbones close to parellel with the ground) and normally allows enough travel to avoid wheelarch contact. I don't have exact settings though & mine's now non-standard.

Yeh my car seems to sit very low, its sitting at whatever height the nitrons were set at as standard, its deff 10mm lower than how the old shocks sat. It does handle very well though!