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K&N Filters


spitrover

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Just Purchased 2 off K&N Chrome Filters  56-9310

Can someone advise if it is a case of a straight swap or should I be expecting some carb tuning issues. I have also purchasses stub stacks. The carbs were rebuilt by Andrew Turner a couple of years ago with little mileage done since. There are no other modifications apart from a set of Magnecor Competition Leads and s/Stwin pipe exhaust

Nice to be back on the forum!!!

 

Regards

Spitrover

 

 

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With K&N filters you may need to change the carb needles to optimise the performance.

 

To give any more indepth advice we need to know what the engine is, what carbs are fitted, and what exhaust / exhaust manifold are fitted, as well as any other relevant engine mods, such as a different camshaft.

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Hi Kevin

1500 Std FM----------Engine, Std SU HS4 Carbs and everything else is std apart fro Twin sports exhaust and Competiton leads. Running on mechanical ignition.

Not really wanting to be a speed merchant but hope mixture can be set with out doing any internal engine damage.

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A lot of people believe that the AAQ needle is the one to use with a fairly standard engine & carbs fitted with K&N filters.

 

You can compare the effect of various needles here - http://www.mintylamb.co.uk/suneedle/

 

Ultimately you cant go wrong with taking the car for a session on a rolling road - with someone that understands SU carbs and has a range of needles available.

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  • 2 weeks later...
  • 1 month later...

For what it's worth, my view is that the just having the K&N filters & sports exhaust won't necessitate any change in needles. Set the mixture up correctly, take the car for a spin & see if it shows signs of running lean. I'm betting it won't.  

 

 

There is a school of thought which says that the fact you're now sucking in hot air from over the exhaust manifold rather than cool air from the front of the car negates some, if not most of the benefits of having free-er flowing air filters. I haven't seen empirical evidence to prove that, but I have to say that running my Vitesse with K&N filters makes no discernible difference to the way it runs, the main plus for me is not having to change the air filters every year. The K&N's will have paid for themselves by now, even taking into account the cleaning fluid & oil they require. 

 

And of course, they look nice!  :) 

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Sorry Peaks and Kevin, but I disagree.

 

Based on past experience with two identical Spitfire 1500s; if you are just changing the filters, you will get away with just adjustments, however if you are changing the exhaust manifold to an extractor manifold as well you will need new jets and springs.  These used to be available as a kit from Club Shop (i know, because I help set the kit up!).

 

In an old article by John Thomason he showed how this was the single biggest way of improving performance.  Both Spitfires that I had experience of generated around 30% more power by just doing these mods.  The rest of the engine was completely standard.  Doing the whole job makes the car a little bit more driveable in modern traffic and is worth the outlay.  BTW, they both had full sports s/s exhausts as well.

 

Hope that helps.

 

Regards

Mike

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  • 5 months later...

Hello all,

 

Im very new to the classic scene and just brought a Triumph Vitesse 1967 Cabriolet.  The engine has been changed to the 2.5 GT6/2500 along with the running gear and axle (i presume).  My question is that the airfilters are missing and it currently has 2 x SU's (not sure what type/size)

 

  • I would like to put on after market possibly K and N but could i ask what would be the best filters to put on it?
  • I would need all the filter inc baseplate etc.

Finally its great to be on here and even better to have the triumph

 

Thank you in advance

 

Rich

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Rich, there never was a 2.5 GT6 from the factory. And 2.5 saloon axle is totally different. Worth checking what you have, as the 3.27 which is the best ratio for a 2.5 is weak, I broke several on my 2.5 vitesse. Likewise the gearbox is probably the std Vitesse one, again it won't like standing starts so be gentle! I used the big saloon box in my car, but it is not an easy swap. Where is reverse?? that will determine which box you have. I hope you have overdrive as well, you will need it!

 

As to filters, first is which SU carbs are fitted. Do the have 4 bolts mounting them to the manifold (or could use 4, if a vitesse manifold is used only 2 will be used) if so they are HS6 carbs, just buy K+N's suitable, and probably the thinner ones, though you may be able to measure the space you have available. If the carbs use just 2 mounting bolts they will be HS4's and will not be ideal for the car.

 

On my car I had a spec of engine that used the saloon very thin airbox. When the engine, standard etc was fitted with the K+N's it went REALLY weak above 2500rpm, and wouldn't go over 3000rpm. I needed to change needles to dolly sprint spec, which were pretty close to ideal when the car was on the rolling road.

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Hello all,

 

Im very new to the classic scene and just brought a Triumph Vitesse 1967 Cabriolet.  The engine has been changed to the 2.5 GT6/2500 along with the running gear and axle (i presume). 

Thank you in advance

 

Rich

 

I would suspect it is still teh original gearbox and rear axle. Much easier that way.

 

Where is reverse? If next to 1st it is small chassis Triumph, if next to 4th it is big saloon.

 

You may be limited with space to the wheel arch if you have twin HS6, so perhaps look for the 2.5S pancake type airbox and remote filter. That may be why you have no filters!

 

Cheers

 

Colin

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Not wanting to hi-jack the thread but I wish they’d bring out a K&N filter that fitted inside the standard air box… I prefer the look of it to the two huge chrome pancakes (used to have them then removed them again) but the original paper filters can be hard to find… anyone know of any straight fit filters of that size?

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Thank you for all the great and helpful replies. The reverse is next to 1st gear so I'll be gentle from standing starts ????. As for the SU carbs how can I tell that they are SUs and not strombergs? I will have a look again tomorrow but I'm sure there was only 2 bolts holding the back plates on so I suppose there HS4.

 

Many thanks

 

Rich

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Sorry Peaks and Kevin, but I disagree.

 

Based on past experience with two identical Spitfire 1500s; if you are just changing the filters, you will get away with just adjustments, however if you are changing the exhaust manifold to an extractor manifold as well you will need new jets and springs.  These used to be available as a kit from Club Shop (i know, because I help set the kit up!).

 

In an old article by John Thomason he showed how this was the single biggest way of improving performance.  Both Spitfires that I had experience of generated around 30% more power by just doing these mods.  The rest of the engine was completely standard.  Doing the whole job makes the car a little bit more driveable in modern traffic and is worth the outlay.  BTW, they both had full sports s/s exhausts as well.

 

Hope that helps.

 

Regards

Mike

Hi Mike

 

My daughter has just bought a 1500 Spitfire with a similar setup, sports exhaust, extractor manifold and K&N filters. It has HS4s with standard springs and needles (ABT). Can you tell me which needles and springs do I need to compensate for the extra breathability? The engine starts easily and runs well at lower throttle openings but feels a bit "restricted" when it is opened up.

 

Regards

Geoff

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Many thanks everyone,

 

Clive thank you for the link to the pics - looks like ive got SUs' just going to find out what typre HS4 or HS6.

 

Does anyone know where the best place is to get some airfilters (K & N website).

 

Many thanks

 

Rich

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