track day tyres / big silencer

[David Thompson]

I'm a newbie on here so forgive me if I ask simple questions.

What tyres are commonly used for track days, other than slicks/wets?

How do track day users get noise down to acceptable limits? Any ideas about the noise reduction achieved by the "big" Clubsport silencer?

[splitpin]

David Thompson said:

I'm a newbie on here so forgive me if I ask simple questions.

What tyres are commonly used for track days, other than slicks/wets?

How do track day users get noise down to acceptable limits? Any ideas about the noise reduction achieved by the "big" Clubsport silencer?

David; no problem and welcome.

If you've got or have in mind getting a Radical, join ROC; contact Founder Will via [e-mail]. He's working on the next Exclusively Radical Trackday and that'll be one to make sure you attend ............. no slow old tin tops with twice the power holding you up!

If you want to get the best fun from a Radical at a Trackday, best stick to slicks or treaded slicks (wets). Mainly you find them on Dunlops, but you can get entirely satisfactory service from alternative makes such Michelin, Avon; even Yokohama as long as you're creative with compensating for size differences. In terms of options, a lot depends on your rim widths.

As long as you look out for the particular limits applicable on the day, there aren't that many instances when you can't comply; if it says 100 max it'll usually mean a 'quiet silencer', whereas say a 105 max will often mean you can use a 'full race can'; but it does depend on the individual car and it's individual exhaust, whether well and recently repacked etc. Our SR4 was MSA static sound tested on Sunday with a one event old properly repacked full race can and it recorded a surprisingly quiet 103.5!

[David Thompson]

Thanks for your reply Splitpin.

I've recently bought a s/h Clubsport for trackdays, and am minded to fit it with Toyo888/Kumo/CR500 type tyres until I can get a second set of rims allowing me to have both slicks and wets. I was wondering what other people used. The car is not here yet so I can't check the rim widths - I think 8" and 10" from memory.

The car is fitted with half used radial slicks, although it is set up for xply at the moment, and was thinking to change these if a more universal tyre was available and in common use. Do most people use radials or are xply preferred?

I guess Goodwood will be a no-no as I can't see me getting it down to the 98/96 they demand, but I might just get onto Castle Combe at 100 static. Another silly question: How does the person doing the testing know what rpm the car is doing when all he can see are the lights?

[splitpin]

David Thompson said:

Thanks for your reply Splitpin.

I've recently bought a s/h Clubsport for trackdays, and am minded to fit it with Toyo888/Kumo/CR500 type tyres until I can get a second set of rims allowing me to have both slicks and wets. I was wondering what other people used. The car is not here yet so I can't check the rim widths - I think 8" and 10" from memory.

The car is fitted with half used radial slicks, although it is set up for xply at the moment, and was thinking to change these if a more universal tyre was available and in common use. Do most people use radials or are xply preferred?

I guess Goodwood will be a no-no as I can't see me getting it down to the 98/96 they demand, but I might just get onto Castle Combe at 100 static. Another silly question: How does the person doing the testing know what rpm the car is doing when all he can see are the lights?

Good for you: I really like Clubsports; proper back to basics track car, sound as a pound on Day One, all these years later and even now capable of being evolved to simply stunning levels .............. if we didn't need two seats ..........

Big G seems to look after Radical Owners, so I'd stick just to slicks until I was able to supplement with wets. A Radical's inherent grip and sheer pace (compared to even such as Evos/M3s etc) will tend to demolish all those 'road legal track tyres' like 888s in no time and to be fair, in merely the damp, the slicks will perform well enough. You'll only need proper wets when it's peeing down and there's more like standing water, in which event, you may decide it's better for a cuppa rather than a soaking wet crotch.

Personally, I'd get the car set up for radials, as you'll have more tyre options, particularly if you are on 8 & 10s. Dunlops made specific for Radicals are standard fitment (ever since Matador disappeared and I think I heard a cheer from RobC just then) and they're radials.

Goodwood (like one or two others) is a tough one, but ROC did hold a Sprint there not so long ago. I know of a quiet silenced SR4 that was OK at a 98 static, all cars being compulsorily tested on arrival.

Hopefully, Rob C & Simon T will be along shortly to tell you all about CC, because if they don't know no-one will.

As to testing, scrut either knows what he's doing and can't be told or he doesn't and may be told (the truth?). We never use more than 9000rpm on ours ....... and that's nearly true, just the odd fluffed gear change from me.

[gixermark]

Hi David,

I'd stick with slicks rather than the treaded options you list to be honest... I've been on both this year - running between competing in a roadsports championship (on cross ply ACB10s) and various 'open' races on radical slicks (dunlops) i too run 8" and 10" rims, but have altered rear widths slightly on the treaded options..

Its best to stick to one set up believe me !! and by far these cars are best on slicks... the set up from cross ply to radial to suit teh slicks you have is fairly straightforward - check ride heighst etc too - as the radial dunlops are a fair bit bigger than the kumho/cr500/toyo etc etc.. There will be a wealth of 2nd hand slicks around from the guys in teh radical series that will be more than fine for track day use anyway - so unless like me you intended to do a 'road' orientated class I'd stick with what these things were intended for :-)

If you need any specifics feel free to e-mail me via here

Mark

[BertBert]

On the silencer front, there have been two generations (or maybe more) of quiet silencer. The current one is very good and allowed me to get on at Combe (trackday). The previous generation was hopeless and I didn't!

The noise tester(s) at Combe do know their stuff and are not to be argued with regarding the shift lights.

My experience at Goodwood is that they don't know about Rad shift lights and they ask you. That gives you a bit more leeway as it were to limit your revs on track and thus declare a lower noise test point

Bert

[David Thompson]

Thanks Bert. I was thinking about buying a s/h silencer but in view of what you say in might make more sense to buy new. I guess they are re-packable.

It's disappointing that Goodwood is so noise restricted - getting through the static test is one thing but the drive by between Madgwick and Fordwater seems to catch people out.

David

[ajh349]

I am in the process of changing my 18 inch exhaust can to a larger size (21 inch). (Prosport 1500)

What sizes are other people using? Interested how many cars are running what sizes and success rates for sound dampening.

Any idea what Radical use/suggest on this engine?

[splitpin]

David Thompson said:

Thanks Bert. I was thinking about buying a s/h silencer but in view of what you say in might make more sense to buy new. I guess they are re-packable.

It's disappointing that Goodwood is so noise restricted - getting through the static test is one thing but the drive by between Madgwick and Fordwater seems to catch people out.

David

Tread carefully on this David.

I don't agree that the new style quiet exhaust is that much better attenuation-wise than the old tea pot style; most of the old style ones will be worse simply because they've done their time, whereas some of the newer ones may have some life left in them. Why? Because unless you can find a specialist expert welder, NEITHER are re-packable. To my mind, if you can find a good one, it doesn't really matter whether it's the new or older style; a good one won't rattle when you give it a good old shake; just make sure it's silence isn't because it's got no e-glass left inside it! It has been known.

If I needed to buy a brand new quiet exhaust, as a possible alternative, I'd be looking at re-packable ones such as Roy Lane's outfit do, rather than one I've got to replace who knows how often, perhaps every year, maybe less, whereas you can do a re-pack (notwithstanding a horrible job) for about £30-ish.

[gixermark]

guy a 'DB Eater' drill a small hole on the tip of the exhasust to clamp it in place - and jobs done.. it worked on mine at donington which is 98db driveby and many of the cars with proper radical quiet cans failed.. They are about £15 and can simply be removed with a 10mm spanner..

[splitpin]

gixermark said:

guy a 'DB Eater' drill a small hole on the tip of the exhasust to clamp it in place - and jobs done.. it worked on mine at donington which is 98db driveby and many of the cars with proper radical quiet cans failed.. They are about £15 and can simply be removed with a 10mm spanner..

Mark

Were do you get those? I had one on a two wheeler Remus Can a while ago, but I recollect they wouldn't sell them separately back then. You'll have to have a projecting end pipe to fix one of those?; there isn't necessarily one on an older radical Race Can and obviously they aren't compatible with the old side pipe tea pot quiet exhaust.

What exhaust was yours and what was the packing like?; tell me it was the race exhaust and the packing was shot and I'll be well pleased! BTW, my good condition old tea pot sailed through as well.

Did I detect right that you sold the Pro ............. what's next 1660 PR06?

[Extremeracer]

I run a Radical SR4 1500 c.c. and have done 3 or 4 events at Goodwood every year for 6 years. After being warned a few times, and suffering one exclusion, when using the original twin exit pipe silencer I bought a largish Techcraft silencer from Roy Lane. It has never failed the static 105 DB test or the 101 DB drive-by. I re-packed it this year in about 20 minutes, - easy peasy. You should note that there are a few 105 DB track days at Goodwood (usually only 5 cars on track at any one time) and of course the first Tuesday in every month is a testing day at 105 DB,s. You virtually have the track to yourself.
As for tyres, you should talk to Dave at BMTR about the Avons that would suit your needs.

[BertBert]

splitpin said:

David Thompson said:

Thanks Bert. I was thinking about buying a s/h silencer but in view of what you say in might make more sense to buy new. I guess they are re-packable.

It's disappointing that Goodwood is so noise restricted - getting through the static test is one thing but the drive by between Madgwick and Fordwater seems to catch people out.

David

Tread carefully on this David.

I don't agree that the new style quiet exhaust is that much better attenuation-wise than the old tea pot style;

Trying not to be argumentative but I have specific experience of the new and old Rad quiet box. I tried two new ones of the previous generation and could get no lower than 105 on a proper noise test at combe. I later tried the new generation one and got to exactly 100 on the proper noise test at combe.

All 3 boxes were brand new.

You are right about whether they last or not being re-packable and I have no experience of that. I did think though that with the debate we had on here about the new-style quiet box a wee while back, there was a reason why they were not needed to be repackable.

So, I'm not specifically recommending the OP buy a rad box over any of the others talked about, just relating my experience with the new and prev gen rad ones

Bert

[splitpin]

Bert Bert, your experience confirms just why one needs to tread carefully; the results are so variable, I suspect even to the point of who packed what and how well at new and I suspect that no two noise tests are ever done exactly the same, be that the tester, the equipment (itself or the positioning) or indeed, the revving. For example, the 103.5 static from our relatively freshly and well repacked full race silencer last Sunday, MSA Scrutineer. Remarkably quiet.

Just to clarify, the previous post established that a Radical Quiet Exhaust does 1) have E Glass in it, 2) therefore that it will deteriorate, 3) that (unlike it's race exhaust) Radical's Quiet Silencer is welded, not rivetted and 4) that Radical no longer offer a re-packing service.

1) & 2) are in effect 'the way things are'. However 3) & 4) mean that, for those of us who may need to use a quiet exhaust pretty regularly and wish to obtain a long and cost effective service life, as things stand at this point in time, Radical's Quiet Exhaust is not the optimum choice. For big budget empowered racers who need use of the same on a more occassional basis and can afford to bin £300-ish quid whenever (be that once, twice or three times a season) necessary, it's not an issue.

A case of patting your wallet to check it's health, deciding which budget camp you're in, making your choice and paying your money. Each to his/her own.

[fergus]

splitpin said:

For big budget empowered racers who need use of the same on a more occassional basis and can afford to bin £300-ish quid whenever (be that once, twice or three times a season) necessary, it's not an issue.

A case of patting your wallet to check it's health, deciding which budget camp you're in, making your choice and paying your money. Each to his/her own.

Not sure why you can't get someone like powerspeed (kent) to fabricate a large repackable silencer for you for less than the original £300? Lots of the Caterham drivers go down this route to try and quieten things down a bit over and above the factory 'queit' silencers.

[splitpin]

Absolutely right, you can (unintended pun) and if you're a budget conscious (most of us are) Trackdayer, you should, hence references to such as Techcraft. The only issue with a Rad is that it has to be sized right to fit under there whereas a Cat has few such issues.

[gixermark]

splitpin said:

gixermark said:

guy a 'DB Eater' drill a small hole on the tip of the exhasust to clamp it in place - and jobs done.. it worked on mine at donington which is 98db driveby and many of the cars with proper radical quiet cans failed.. They are about £15 and can simply be removed with a 10mm spanner..

Mark

Were do you get those? I had one on a two wheeler Remus Can a while ago, but I recollect they wouldn't sell them separately back then. You'll have to have a projecting end pipe to fix one of those?; there isn't necessarily one on an older radical Race Can and obviously they aren't compatible with the old side pipe tea pot quiet exhaust.

What exhaust was yours and what was the packing like?; tell me it was the race exhaust and the packing was shot and I'll be well pleased! BTW, my good condition old tea pot sailed through as well.

Did I detect right that you sold the Pro ............. what's next 1660 PR06?

I bought mine off ebay a few years back... its a generic one that fits any straight exit can - relaly designed for bikes - and is why i bought it at the time.. but obviously serves the radical very well...

Yes - Hopefully the Pro is moving onto a new home... shame in many ways, but the racing here is not great for them to be honest.. and i ain't got the budget to race in england soley.. 1660 PR06 - I wish !! that woudl be quite a ride while the motor held together

[David Thompson]

Thanks for all these replies - very useful to me. it seems the way I have to go is, after market repackable can (which is what I did with my Caterham with good results,from Raceco) and stay with slicks.
Should I assume the Radical will be as delicate in the wet/damp as the Caterham is, or more so?

[splitpin]

David Thompson said:

Thanks for all these replies - very useful to me. it seems the way I have to go is, after market repackable can (which is what I did with my Caterham with good results,from Raceco) and stay with slicks.
Should I assume the Radical will be as delicate in the wet/damp as the Caterham is, or more so?

Correctly set up and shod, on virtually every track, the Rad will be just as capable of walking away from any Cat (and virtually everything else) in either and that is absolutely no exaggeration

[Martin B]

ajh349 said:

I am in the process of changing my 18 inch exhaust can to a larger size (21 inch). (Prosport 1500)

Alan, are you interested in selling your old silencer? I know the condition as I saw you repack it at the last Combe race.

I am going to need another one for my car for next year

Martin