Radical SR8

Its a great photo, and I just love the heat haze mixing with sea and waves - I ordered a big print last night for the garage wall

I have to consciously force myself to push the car, its not intuitive yet, driving what you would think of as fast is just no where near especially in the fast corners - there's 2 corners at Anglesey which are certainly flat out but I just cannot quite force myself to do it........its coming, better every time, but the speeds are high and frankly it starts to get scary. So I am still having to push myself to just trust the car and go faster. It gets better through a weekend as you realise again. Unless you have been driving aero cars for years, I reckon you have got to do it regularly at least once a month to get into the groove.

Jumping back in a road car is like someone pressed the pause button. But I'm that blown away usually on the way home that I drive dead slow LOL.

 

Exhaust noise was getting a bit marginal at Anglesey at 107db @ 7K rpm (static tail pipe test) so silencers repacked, again. Lasted about a year.



Car sound and feel is sharper since the engine was rebuilt so exhaust will be getting some stick.

 

A few times at last Anglesey event rear of car felt a bit light so thought I would check up on aero settings. Have never really bothered with this before now as its not that clear in the Radical Mechanics Handbook what the various levels are....only mentions High/Med/Low, but no more detail as to what these things mean.

So spoke to Radical technical who told me that Low was hardly never used in the UK, and was for very quick circuits such as Monza. Silverstone was considered a Medium aero track, and Anglesey a High aero track.

Aero can be tuned on the SR8 using the rake of the car, and also the addition of front dive planes, and the angle of the dual element rear wing.

Low aero is no front dive planes, rear main wing 'flat' (hole 1 or 2), and rear wing flap hole 2 or 3
Medium is one front plane, rear main flat, and rear flap hole 5 or 6
High is two front dive planes, rear main flat, and rear flap hole 7, 8 or 9

Have upped the rear flap a bit. See how we go.

These settings are much more important in SR3s than 8s as they have much less power to drag an over draggy car about.

Also had some really useful feedback from one of Radical pro drivers on some data traces and video. Good news is that I'm apparently driving the car very well, but there are improvements still to be had. All good.

 

Another 2 pbs this weekend, 0.8sec off on Sunday GP Circuit to get into the 84s for first time. Second overall behind big Gould. Blistered rear tyre. More soon.

 

So are starting to feel like I'm getting this car now and last time out were certainly pushing what it can do. So time to try and make it a bit quicker.

Couple good new pics to begin





So are going to try and get some weight out of the car. Starting figure 721kg. Big double seat and associated passenger bits can be swapped for a much lighter Radical single seat, that is not only lighter but much more supportive. And centralises driver weight by a couple inches. All worth having.



Big seat with pads, 11.1kg. Small seat, no pads needed, 4.2kg. Saving 6.9kg.
Headrest, bar pad, floor matting, 1.3kg.
Passenger 6 point seatbelt set, 2kg

Car has two big batteries like Red top 30s, 9.5kg each, so they can be swapped for lithium saving probably 16kg.

Bodywork bits
Front splitter 11.3kg, is made from plywood inside
Rear diffuser with internal steel support frame 11.7kg
Front body with no lights and 2 diveplanes 14.3kg
Rear body with lights, rain light, carbon wing and steel internal supports, 23.6kg

Wheel tyre combos
Radical forged 8x15 front with avon slick, 15.2kg
Radical forged 10.5x16 rear with avon slick, 18.2kg
Set of split rims saves 8kg on a set.

If bodywork bits could be made in carbon, and all rear lights and wiring removed, it might half the weight i guess, 30kg saved.

Front footwell water cover 1.5kg.
Big ATL 77L tank, 6kg. Lots heavy rubber breather tubes for dump churn filler. Could be 7kg to be saved there.
Could make all non floor chassis panels in ali rather than std steel...hmm.....

So 35-40kg relatively easy to save, 65-70kg considerably more costly. So a 650kg SR8 is doable, but cost high for external body bits.

So....probably a combination of light lower-risk engine tuning and sensible cost-achieveable weight savings is way forwards.

 

Just got me a set of Image split rims for SR8.



Thats the Billet 4 wheel.

http://www.imagewheels.co.uk/billet-4-alloy-wheel/

Front with tyre 13.3kg, rear with tyre 15.9kg.

Compares with forged items 15.2 / 18.2.

Saving 8.4kg, and unsprung mass too. These are getting a set of new tyres for that special moment.....

 

Okie dokie, cracking day last Sat at Aintree for Liverpool Motor Club Summer Sprint. First time back there after changing to shorter gearing plus a few other changes so was interested to see how things went. In the run up the weather changed nearly every day from full dry, to full wet, to drizzly all day so set the car up for damp and set off. On the day it was showing drizzle but improving all the time. Ground was dry so decided to run first practice with wets, and then swap over to slicks and dry setup. One other car in 4A, Midland Speed regular David Large in a 1300 Radical PR6, and one other in 4B with me, David Marshall in a 6.3L Lola T70....yeh.

Previous best times 2.35, 28.40, 43.76 (146).
Class record Jim Belt Juno TR400, 42.97 (2012) about 150mph

Times are 64ft, Beachers split, Finish (mph).

P1, 2.57, 31.90, 48.45 (143), nice and steady on wets, sense and system check
P2, 2.33, 28.70, 43.90 (143), better, on slicks
T1, 2.25, 28.40, 43.04 (143), get in, new PB and 5 hundreths from class record
LUNCH.....hmm.....want to get on with it
T2, 2.32, 28.10, 43.02 (142), get in again, new PB
T3, 2.33, 28.80, 43.16 (143), hit the brakes too early for beachers....
Went to line and was told next run would be final for day, focus time, sun actually came out too
T4, 2.28, 28.00, 42.77 (142). 'AVE IT.

PB and new Unlimited Sports Libre Aintree Record! lowering the previous record by a significant 2 tenths from the long standing BSC campaigner Jim Belt.

This is the most significant result from 15 years of sprinting. So chuffed.

Will put some photos up when i get them.

More soon.

Results and photos here http://www.liverpoolmotorclub.com/2017/06/25/results-and-report-for-the-june-2017-aintree-sprint/

Cheers

Rob

 

Brilliant that you're getting on so well in your first proper season with the car

Reaping the rewards for practice, money spent and English engineering ingenuity lol

 

Ta. Starting to connect with car now, chucking it about a bit, and made a cracking suspension tweak for Aintree that really helped for that track , compliance with control is the name of the suspension game.

After the Anglesey record next. Different setup needed though.

 

Rob you inbox is full

 

Happy with the aero now Rob?

 

inbox is full as my membership has lapsed and its got loads in there. aero tweaks to rear wing are noticeable so i can use these now to fine tune balance. Front is less tuneable.

 

Good reason to spend the price of a couple of Cheshire pints then Rob lol?

You got my text so sorted anyway

 

That`s bloody outstanding ! No wonder you are chuffed

 

We need a 'love button' on the forum

Preparation of equipment and focus has paid off big time!

Liking this story.

Look forward to the next outing

 

Anglesey record next. Oh yes, it will be mine

 

Well done Rob. Nice when it all comes together!

 

Thanks all.

 

Couple of interesting things - Image Billet 9 split rims are exactly 6.7kg a set lighter than the Radical forged items (1.88kg for a rear wheel and avon slick radial tyre (18.68 vs 16.80), 1.47kg for a front (15.12 vs 13.65)), this now I have got a more accurate weight with all the crud scraped off the tyres fitted so everything is comparable. Thats pretty significant saving for a set of wheels, unsprung mass and all that.

As always things are never that simple and although the 16" rears are a direct fit, the 15" fronts fouled the brake calipers with the 300mm disks my car has fitted. The bit that caught was the nuts on the back of the split rims:



This has now been solved by fitting some dome head bolts from the inside, and the nuts on the outside. 10.9 grade zinc plated rather than stainless, torque to 13ftlb. Dome heads were needed as regular square cap heads still caught the caliper. 1mm thick washer. Have sometihing in the order of 2mm clearance now which should be enough. Thats a big disk under a 15" wheel....

Pics from Aintree:

 

You gotta love polished ali billet. Spent 2 days stripping and cleaning 2 front wheels. Ready for new bolts now which shpuld be arriving tomorrow.