CAI/Induction. Alta vs GTT vs JCW/GTT vs K&N etc... Which to choose?
I realise that there are endless threads on this already, I have spent many hours (when I should have been working) reading through them, but please bear with me.
I have an '05 model MCS which will soon be out of warranty so I have been trying to decide what bits to put on it. I already have an exhaust sorted so my thoughts are now turning to induction.
Originally I was thinking of going for a K&N Typhoon kit but it seems from what I've read here that the only two kits that I should really be considering are the Alta and the GTT. Unfortunately I have some reservations about both and I'm hoping that someone in the know might be able to put to rest some (or all) of my fears so that I can get on and make a decision.
Firstly the GTT.
It seems that many are now choosing this over the Alta but my worries are as follows:
1) I don't think that it looks very tidy.
2) To get the real benefit from it you have to drill holes in your bulk-head panel (although maybe you could just buy the JCW panel which already has a nice hole in it, or even the mini-madness panel which has a really big hole in it??)
3) Possibly the most important problem for me with this one is that the only thing stopping unfiltered air from making it past the filter and into the engine is a rubber O-Ring which relies on 4 flimsy looking springs to keep it in contact with both the filter and the tube it is attached to (surely there must be a reason that everyone else uses a pipe clamp to keep the filter in place??)
Now the Alta.
I personally think that this makes the engine bay look much neater than the GTT because of the replacement bulk-head panel, but:
1) Fitting the bulk-head panel you get with the kit means that the ecu is more exposed to the elements because it is no longer sealed in the engine bay.
2) I'm sure I read somewhere that the Alta is annoyingly loud (I do want a better engine note, that's partly why I want a CAI, but I don't what to upset my neighbours in the morning when I pull away (is there a big noise difference at low revs?), and I would quite like to be able to use my hands-free kit when I'm driving on a motor way).
I'm also considering the JCW race box with the GTT upgrade as it would be much better to look at than the GTT kit, but again I'm facing the problem with the O-Ring and the springs (even more so in fact, as the O-Ring would have to seal against the inside of a plastic box instead of a nice machined metal sealing face (maybe a bit of K&N sealing grease might help??))
Another thought I had was the Ultrik kit, which is basically a K&N conical filter and a heat shield. I could buy this kit and then add a bulk-head panel with a hole in it, but I'm not sure whether a K&N would give me as much added power as the others (even if it is getting air from the scuttle vent area), or whether it would give me a noticeably nicer engine note.
I know that this has been a lot to read but some thoughts on the things I've said here really would be very helpful.
Hi, our kit uses the original dividing panel drilled therefore you can choose how large the hole is ,which gives you the control over the volume (loudness) . The stock panel is inexpensive (about £10 ?) should you ever want to replace it. The GTT kit is also much easier (&quicker) to install than the Alta, & you can revert it back to stock airfilter/ airbox in under 5 minutes (some people do this for servicing) .The GTT kit is also twin skin to shield the heat away better ,and is made of anodised aluminium which is much lighter than the mild steel single skin of the Alta. Another unique feature of the GTT system is a a true 360 degree rolled edge rampipe for optimum flow.-Average power gains (depending on other mods) is around 10bhp. The springs are very effective ,we have adopted this system from our Renault design ,which we use in both gravel (forest) rallying & tarmac rallying ,without any problem for over 13 years. Sorry you dont like the look , the only option is a red element in place of the blue,
Best Regards Roland GTT
Out of all of the above my choice which i have is the ALTA..
1. it is not Loud you get the "air sucking noise" and it enhances the supercharger noise
2. the ecu is not open to any elements as it will be in the same location and still sat in its same little box as it was.
3. i had the JCW air box before which was modified by removing the flap and the electronics, yes it was good and you notice the difference in sound and power gains but it still doesnt come close to the ALTA.
the ALTA looks the part and sounds amazing, its one of the best selling AIR FILTER products over in the USA as it is such high quality and a proven product.
EMPTY SPACE NEEDS FILLING....
but it has to be something that wont get me banned
Hi Roland, thanks for your input.
I didn't realise that the spring thing had been around (and working) for so long, so I'm sorry for doubting.
I'm now thinking that the JCW racing box with your filter might be the way to go, am I right in thinking that you have to modify the box slightly to acommodate the springs? And does this provide a decent seal (having not actually seen a JCW box open I cant picture what the inside sealing surface is like). Finally, would doing this rather than the full GTT kit provide a decent improvement in sound over the standard box?
hi, AMF if you already have the JCW airbox the GTT/JCW Hybrid filter is a popular choice as is relativley inexpensive and utilizes/upgrades what is already there. In terms of performance it fits 'half way house' between the JCW filter and the full GTT Cold Ram KIt, therefore if you currently only have the stock air filter the GTT Cold Ram would be the better choice.
Best Regards Roland GTT
I'd agree with Jon on this one, I have the Alta and I absolutely love it. The sound is by no way annoying, and it isnt loud. When you put your foot down that it when the noise is, but you cant hear at any other time, even when accelerating under normal acceleration its very quiet.
Power gains were very noticeable, much better throttle response and the car just feels more eager to go. I wouldnt chage it to anything else and I think it looks really good under the bonnet with the bright red foam funnel and air intake pipe - its the most prominent thing under the bonnet for sure!
asthetics aside you wont relay go wrong with either as both have proven perofmace gains of arround 8 horses the only addion i would make to the GTT kit would be a samco induction hose as the normal hose has ridges in it that can create intake turbulance (the alta kit come with its own hose) aside form that they are both very very good kits imo me well i will ahve to make my mid up when i get my S but will probs plum for the hybrid to keep a more stock look under the hood as i have heard good things about the jcw / gtt hybrid too
minitorque.com, the site for mini performance, drag racing track days & time attack
I had to order it directly from Madness/US though.
I just drove some 3000+ km with Madness JCW filter + the flap mod + also removed the blanking plug from the lower part of the box (it sits inside a fold in the rubber gate between the airbox and the plastic engine bay shroud). NIce.
I have an Alta and charger whine inside the car is increased...I did not have a replacement panel for the scuttle area...mine sucks from the hole airbox and scuttle as that diving panel is removed totally. The suck is not greatly increased and until its opened to full throttle noise from the alta is not high, especially from outside the car.
The GTT is slightly better kit IMO but the Alta was a steal when I got it from the US and its not hard to fit and its red which is what swayed me as the blue of GTT wouond't have looked as good under my bonnet
This question for Roland, but if anyone else knows just chime in.
The vent hose from the rocker cover to the intake pipe upstream from the throttle body is supposed to handle excess blowby under high rpm loaded conditions. Is this ever the case with the S?? I would expect that the pcv line would handle this volumn easily given that the high rpm full load condition is when the supercharger is putting out maximum boost (and sucking hardest at the throttle body.) Wouldn't the vacuum downstream of the throttle body where the pcv connects be high enough to handle any condition?? Has your testing indicated anything other than some kind of filtering needed for the breather hose?
Cooper S Red/White/White, Air, Computer, Cloth, DSC, Cold Weather. August build.
Hi, highest 'suck' or negative pressure is on overrun& idle, at this condition crankcase fumes etc are drawn or sucked through the pcv valve and put back in downstream of the throttle. At WOT the pressure upstream and downstream of the throttle are (virtually ambient pressure) identical and therefore the fumes then take the easier path of exiting the rocker cover at the other end and are put back in upstream of the throttle. The higher positive pressure you get at WOT with more blowby past the rings helps compensate for the lack of neg pressure in the inlet tract, ensuring some flow still occurs. For upgrades use the GTT OCC on the PCV circuit . You can also put a small breather filter on the hose from the other end of the rocker cover if you wish. Remember to use a stepped bung to block the hole in the inlet hose aswell.
Best Regards Roland GTT
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CAI/Induction. Alta vs GTT vs JCW/GTT vs K&N etc... Which to choose? 
