Hi All,
Had the first race meeting in my McLaren M1B replica last weekend at the MG Classic meeting at Manfeild, and wanted to pick your brains.
Suspension is basically identical in concept and execution to original GT40. I am running modern racing slicks 330/680/18 rear (20psi cold) and 240/640/17 front (24 psi cold), with about 0.5 neg camber rear and 1.5 neg camber front, 3/16 toe in each side rear, zero front toe, 4.5 inch static rear ride height with a wing that puts about 150kgs on at 150mph, 3 inch front, about 870kg + driver, 37/63 front/rear weight distribution. It has a 930 transaxle with a Kaaz LSD in it.
Springs are 450 rear, 400 front, adjustable roll bars set half way rear, full soft front. I have spax shocks with adjustable rebound only. My rebound “tuning” technique has so far consisted jumping up and down on each end of the car with my full body weight and going up from full soft so that I get just get to the stage where my antics produce no secondary bounce oscillation – i.e. just a bump then a single smooth rebound.
At the back this point is 12 clicks from full soft – about half-way. At the front it feels like rebound could already be too firm with the shock at full-soft, so I left them there.
So now for the question. As my confidence with the car increases, it feels stable and benign at the back, takes full power pretty early off the turn with no oversteer tendency, and is good over bumps. At the front however, real precision is required to get it turned in without too much corner entry speed or it will wash out quite badly. It is very much a slow in fast out machine at the moment, and I would like to improve front end grip. I do not want to achieve this by tightening the rear because that feels really good. Given the front bar is already full-soft, my first move would have been to reduce front rebound if I could – can’t do that either. I guess I could disconnect the front bar and see what that does. Thoughts?
Cheers, Andrew Robertson, Wellington NZ
Had the first race meeting in my McLaren M1B replica last weekend at the MG Classic meeting at Manfeild, and wanted to pick your brains.
Suspension is basically identical in concept and execution to original GT40. I am running modern racing slicks 330/680/18 rear (20psi cold) and 240/640/17 front (24 psi cold), with about 0.5 neg camber rear and 1.5 neg camber front, 3/16 toe in each side rear, zero front toe, 4.5 inch static rear ride height with a wing that puts about 150kgs on at 150mph, 3 inch front, about 870kg + driver, 37/63 front/rear weight distribution. It has a 930 transaxle with a Kaaz LSD in it.
Springs are 450 rear, 400 front, adjustable roll bars set half way rear, full soft front. I have spax shocks with adjustable rebound only. My rebound “tuning” technique has so far consisted jumping up and down on each end of the car with my full body weight and going up from full soft so that I get just get to the stage where my antics produce no secondary bounce oscillation – i.e. just a bump then a single smooth rebound.
At the back this point is 12 clicks from full soft – about half-way. At the front it feels like rebound could already be too firm with the shock at full-soft, so I left them there.
So now for the question. As my confidence with the car increases, it feels stable and benign at the back, takes full power pretty early off the turn with no oversteer tendency, and is good over bumps. At the front however, real precision is required to get it turned in without too much corner entry speed or it will wash out quite badly. It is very much a slow in fast out machine at the moment, and I would like to improve front end grip. I do not want to achieve this by tightening the rear because that feels really good. Given the front bar is already full-soft, my first move would have been to reduce front rebound if I could – can’t do that either. I guess I could disconnect the front bar and see what that does. Thoughts?
Cheers, Andrew Robertson, Wellington NZ
