24 replies to this topic

[jimmyH]

Hi guys, I have had my mini a few months now and love it !! Given him some new shoes and slowly cleaning out the engine bay and touching up the minor imperfections. However there is one thing i have been wanting to spruce up since i got him. The pea shooter.
I am asking for people's oppinion on the best back box to get. Wanting a classic burble rather than a boy racer trumpet . Although something that is not too obtrusive on the motorway! Oh also has to be center exit either double or single pipe.
I am faced with one other dialema however. My insurance company couldnt give two hoots what i do to my car ASLONG as it does not change the performance of my car. Will simply a back box alone cause my insurance company to ask me to pay insane amounts of money for this modification. (simply the back box and linkage, no LCB or manifold)
Oppinions and ideas would be great.
Thanks
James

[Pauly]

Your premium will go up a bit by adding a stage 1 kit and if your fitting a new upgrade exhaust then you might aswell go the whole way and buy a stage 1 aswell. You will probably be best buying a new exhaust manifold as it would benifit your new system, again, this is part of the stage 1.

Maniflow or RC40 systems are the best to go for, they do loads of different styles and conifgurations.

Paul.

[Cooperman]

Don't take too much notice of this "Stage 1", "Stage 2", etc., as it's pretty meaningless.
If you simply clean up the combustion chambers by die-grinding out the rough edges and smoothing it out generally, then that is a finishing-off process rather than a modification. It used to be known as "blueprinting".
As for the exhaust, you don't sat whether it's a 998 or a 1275. If it's 998 go for a 1.625" diameter pipe with, ideally, a Maniflow or RC 40 back box. Tell the insurer that you have fitted a good and improved quality replacement non-O.E. exhaust pipe to replace the old one.

[Nightrain]

Afraid it doesn't quite work like that now-a-days cooperman, insurance companies want to know anything that will increase performance.
In the event of a serious accident, a head modified such as your suggesting, would be deemed as a performance modification. Even possibly a stage 1 head.
The best way forward for jimmy would be to cut 4 inches off the tail pipe and fit a chrome end, this would give the looks and the sound to an extant. But you wouldn't need to tell them you've fitted a performance part, because you haven't just a chrome tail pipe.

[Cooperman]

'Blueprinting' means bringing the engine to the optimum build standard allowed by the manufacturer's 'blueprints', or design drawings to use the correct expression. I'm not suggesting opening up the inlet or exhaust tracts, altering the combustion chamber shape, just cleaning up the manufactured standard to that actually intended by the manufacturer, but not achieved due to manufacturing tolerances. For example, you can get some really quite good head castings with almost no valve seat mis-match. Others have a big valve-seat mis-match. As originally intended there should be no mis-match at all. If this mis-match is cleaned-up and if the head was removed and measured it would come up as standard. Similarly, the workshop manual says that as a service repair the head can be skimmed up to 0.025". You don't need to declare any service repairs as mods, even though they may very slightly increase performance. Boring a 1275 to 1310 cc will give about 2 to 3 bhp extra, but it's not a modification, it's a service repair.
It's similar to cam timing. Standard cams should be timed in at 110 deg ATDC, but production tolerances can vary this by quite a large amount. I just built a 1330 cc unit where the standard cam timimng came in at 9 deg retarded before correction. It is hardly a modification to correct this manufacturing error using an offset woodruff key, it is 'blueprinting'.
With regard to the exhaust system, it's not a mod. to fit an aftermarket pipe and box, so long as it conforms to the original in terms of size and fitting. If a centre-exit pipe is fitted, then, yes, it's a mod., but there is nothing to prevent the fitting of a non-OE unit. If that were the case then virtually every Mini that has ever had the exhaust replaced would be deemed 'modified'. If in doubt, tell the insurer that the exhaust pipe has been replaced with a non-BMC/BL/Rover unit of improved quality - any system other than the BMC/BL/Rover unit will be of improved quality, especially if it's stainless steel.

[m1tch]

Blueprinting is bringing the engine back to how it was designed, getting rid of any imperfect castings and tuning it up a bit What I don't get with insurers is how a new aftermarket part that will last longer then OEM is bad, and how being able to safely overtake with a tad more power on the motorway is bad

[Nightrain]

I know what blueprinting is............. but if an vehicle inspector was to look at a cylinder head that was ground, they would deem it as a modified head ! Same with offset keys, it is a non-standard part you've fitted to increase performance, or that is what they will say !
They will try to get out of paying with any discrepancy from original, I know what your saying and am only warning people of what does happen !

If you simply clean up the combustion chambers by die-grinding out the rough edges and smoothing it out generally,

[jaydee]

Hi guys, I have had my mini a few months now and love it !! Given him some new shoes and slowly cleaning out the engine bay and touching up the minor imperfections. However there is one thing i have been wanting to spruce up since i got him. The pea shooter.
I am asking for people's oppinion on the best back box to get. Wanting a classic burble rather than a boy racer trumpet . Although something that is not too obtrusive on the motorway! Oh also has to be center exit either double or single pipe.
I am faced with one other dialema however. My insurance company couldnt give two hoots what i do to my car ASLONG as it does not change the performance of my car. Will simply a back box alone cause my insurance company to ask me to pay insane amounts of money for this modification. (simply the back box and linkage, no LCB or manifold)
Oppinions and ideas would be great.
Thanks
James

Get old of a complete later cooper exhaust, size is 1,65" while your just a 1,5".
Will notice a performance improvement, still quiet but with nice 'classic' sound.
Everyone is getting rid of them, so you will easy get one for a few quid.

[jimmyH]

Hi guys, I have had my mini a few months now and love it !! Given him some new shoes and slowly cleaning out the engine bay and touching up the minor imperfections. However there is one thing i have been wanting to spruce up since i got him. The pea shooter.
I am asking for people's oppinion on the best back box to get. Wanting a classic burble rather than a boy racer trumpet . Although something that is not too obtrusive on the motorway! Oh also has to be center exit either double or single pipe.
I am faced with one other dialema however. My insurance company couldnt give two hoots what i do to my car ASLONG as it does not change the performance of my car. Will simply a back box alone cause my insurance company to ask me to pay insane amounts of money for this modification. (simply the back box and linkage, no LCB or manifold)
Oppinions and ideas would be great.
Thanks
James

Get old of a complete later cooper exhaust, size is 1,65" while your just a 1,5".
Will notice a performance improvement, still quiet but with nice 'classic' sound.
Everyone is getting rid of them, so you will easy get one for a few quid.

But is it possible to claim that if i just changed the back box alone. Not trying to improve performance just want a nice sound . Surely the backbox does not improve the performace that much? not changing LCB or anything ...

[m1tch]

*removes backbox completly* *goes deaf soon after* lol

[jaydee]

[quote name='jimmyH' post='1555004' date='Aug 17 2009, 04:11 PM'][quote name='jaydee' post='1554800'
But is it possible to claim that if i just changed the back box alone. Not trying to improve performance just want a nice sound . Surely the backbox does not improve the performace that much? not changing LCB or anything ...[/quote]

Nah you need the whole system, it has different piping and manifolds.
Anyway a bigger backbox will improve performace over the standard peashooter, im not jocking.
The 1,75" exhaust on a 998 is a bit overrated.

Edited by jaydee, 17 August 2009 - 04:41 PM.

[Cooperman]

[quote name='jaydee' post='1555035' date='Aug 17 2009, 05:40 PM'][quote name='jimmyH' post='1555004' date='Aug 17 2009, 04:11 PM'][quote name='jaydee' post='1554800'
But is it possible to claim that if i just changed the back box alone. Not trying to improve performance just want a nice sound . Surely the backbox does not improve the performace that much? not changing LCB or anything ...[/quote]

Nah you need the whole system, it has different piping and manifolds.
Anyway a bigger backbox will improve performace over the standard peashooter, im not jocking.
The 1,75" exhaust on a 998 is a bit overrated.
[/quote]

For a 998 you need a 1.625" pipe inside diameter. The 1.75 is correct for a 1275 and upwards.

[jimmyH]

Shame, oh well i will have to think of some alternative that will not put up my already ridiculously expensive premium.
Thanks guys, helpful as always

[jimmyH]

I am still thinking about getting a new back box only, with link pipe of course. If i bought one that was the same diameter as my stock system, just as restricting. Would it improve my performance.
I dont want it to because if it did = higher insurance premium.
I just want the nice noise, better look.
Thanks Guys

[Pauly]

Anything other than standard exhausts will be better on performance but I wouldn't think it would improve performance just by fitting the exhaust, its when you change manifolds and airfilter etc. But if your fitting an upgrade system then its best to get an upgraded manifold aswell (otherwise use a magic pipe to retain the standard manifold) if your going to buy and upgrade exhaust manifold then you will need a seperate inlet manifold, you might aswell add the air filter and needle and make it into a stage 1.

Fitting an upgrade exhaust just for the noise is a lost cause to me.

Paul.

Edited by Pauly, 01 September 2009 - 05:13 PM.