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Best sound per pound - Are HFCs & Plenums essential?


Dynamic Turtle

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Hi Guys,

 

I'm seriously considering taking Abbey up on their Uprev/MIlltek package and wanted to know how worthwile it would be adding HFCs, plenum and air filter upgrades in to the mix. HFCs are pretty expensive, along with plenum upgrades. I'm most interested in getting the nicest sound rather than increasing performance and everyone seems to rave about the HFCs. Are they worth £400 + extra hassle at MOT time? Do plenums & special air filters deliver aural benefits or are they primarily performance upgrades?

 

Also, I called Admiral with respect to uprev/milltek changes and want to charge me an extra £31 for them, fair enough. But they said that HFCs were "category 9 declined" for some reason and wouldn't quote me! What's the deal here?

 

Cheers,

DT

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If you are not fussed on performance, why spend the extra cash on Uprev, HFCs and plenum? just buy a good quality exhaust, and fit a air filter yourself. Obviously the Uprev will give you more performance wise, but think its more the drivability that you'll notice.

 

Milltek is very quiet...hence why I'm going to try decats. If the sound is fine (not too loud..LOL), may look at HFCs. But as you mentioned, they aren't cheap so want to be certain first - hence the decats.

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HFC's should pass an MOT and they definitely give an extra roar when you get above 2.5k revs. I had mine fitted at Abbey along with the spacer, so I couldn't tell what the spacer added on it's own. I hear that it does make a slightly lower growl. I'm pleased with the new sound anyway!

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If you are not fussed on performance, why spend the extra cash on Uprev, HFCs and plenum? just buy a good quality exhaust, and fit a air filter yourself. Obviously the Uprev will give you more performance wise, but think its more the drivability that you'll notice.

 

Milltek is very quiet...hence why I'm going to try decats. If the sound is fine (not too loud..LOL), may look at HFCs. But as you mentioned, they aren't cheap so want to be certain first - hence the decats.

 

That is a good point, but then abbey will charge fitment costs for the milltek (effectively you get the uprev at subsidised cost) and it does seem like a worthwhile upgrade for the money, even if it's performance related.

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Hfcs were the best thing i added to my car, combined with the milltek the noise was fantastic.

 

It may trigger the ecu light though so remember to get mark to sort that for you

 

Wouldn't that be done as part of the Uprev anyway?

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Rather decats myself that's where the best noise comes from IMO, I had silenced decats buy found them to loud with my current exhaust so bought some motordyne art pipes instead. There's no better sound than these bad boys trust me :)

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  • 2 weeks later...

by having the decat pipes/art pipes does this make alot more of a difference to the sound? as i want to get a nismo exhaust as i love the sound it makes!! and with decats it may sound even better but im worried it will be too loud and drone on motorways?

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Well I'm liking the sound of the MIlltek/HFCs thus far, but I've only put 150 miles on them. I would say it's a good balance between motorway quietness and a sudden roar upon flooring the throttle, which is precisely what I wanted. There is some wooshing and hiss from the HFCs but it's far from intrusive and actually quite cool. There is a little bit of rattle and rasp from the Berks from time to time but it's a "feature" of the design according to Tarmac. The overall effect is great and the exhaust now sounds much better accelerating in 1st (which is the major weakness of the OEM zorst, IMHO) and whenever you're WOTing it.

 

Difficult to say what difference the Uprev has made though (gained 10whp, 7lbft). The car feels fractionally sharper and more responsive in the lower gears even if the dyno graphs point to virtually zero difference. Not sure if it's a £400 upgrade TBH, but I need to spend more time driving the car in drier conditions because the rain may have been affecting traction. Power increases were also limited by virtue of the insurer refusing to cover a plenum spacer and custom airbox.

 

Visually I'm a little disappointed that the Milltek's tailpipes aren't as polished/shiny as the OEM pipes nor are they slash-cut, which suits the aesthetic better.

 

Oh and great service from Abbey as usual :)

 

DT

Edited by Dynamic Turtle
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Well I'm liking the sound of the MIlltek/HFCs thus far, but I've only put 150 miles on them. I would say it's a good balance between motorway quietness and a sudden roar upon flooring the throttle, which is precisely what I wanted. There is some wooshing and hiss from the HFCs but it's far from intrusive and actually quite cool. There is a little bit of rattle and rasp from the Berks from time to time but it's a "feature" of the design according to Tarmac. The overall effect is great and the exhaust now sounds much better accelerating in 1st (which is the major weakness of the OEM zorst, IMHO) and whenever you're WOTing it.

 

Difficult to say what difference the Uprev has made though (gained 10whp, 7lbft). The car feels fractionally sharper and more responsive in the lower gears even if the dyno graphs point to virtually zero difference. Not sure if it's a £400 upgrade TBH, but I need to spend more time driving the car in drier conditions because the rain may have been affecting traction. Power increases were also limited by virtue of the insurer refusing to cover a plenum spacer and custom airbox.

 

Visually I'm a little disappointed that the Milltek's tailpipes aren't as polished/shiny as the OEM pipes nor are they slash-cut, which suits the aesthetic better.

 

Oh and great service from Abbey as usual :)

 

DT

Have Milltek changed the tail pipes then? Here's mine after 700 mile to SW France.

 

TotalNissan4.jpg

 

The torque gain throughout the range is far more important than the extra bhp, what gains did you make in torque, you really should be noticing substantial differences in 2nd and 3rd :)

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Admiral were a nightmare, it took 1.5 hours on the hone being bounced around 3 call centres across the globe, but finally the one smart guy in cardiff acknowledged that the cats would be covered, but still couldn't allow the plenum and airbox for god knows what reason...

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Papa, it probs just needs a good polish but the metal is yellower than normal, rather than shiny chrome. As for torque, there are marginal 5-10lbft gains from 2000-5000rpm according to the graphs but it's not something i've been able to detect thus far. Only noticeable gain is in first which sounds much nicer and more willing to hit 25mph (was changing up around 18mph before).

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The car feels fractionally sharper and more responsive in the lower gears even if the dyno graphs point to virtually zero difference.

 

Dyno only shows full throttle dyno pull it doesn't show part throttle response, The Uprev main gain is the lower gear throttle response as well as the fueling and Ignition maps set up for the mods added.

 

Running the HFC's always makes the car loose a little torque at under 2000rpm on full throttle but how many times do you drive a car like that , full throttle 4th gear under 2000rpm?

 

Running without the plenum spacer will lose the normal gain in Mid range torque as well.

 

Also the dyno plots isn't your car stock versus you car after fitting the Abbey Motorsport performance package, we fit the parts then run the car on the dyno with the stock car ECU map then remap the car. So it is a before and after remap dyno plots NOT stock versus APP ( Abbey Performance Package)

Edited by Mark@Abbey m/s
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The car feels fractionally sharper and more responsive in the lower gears even if the dyno graphs point to virtually zero difference.

 

Dyno only shows full throttle dyno pull it doesn't show part throttle response, The Uprev main gain is the lower gear throttle response as well as the fueling and Ignition maps set up for the mods added.

 

Running the HFC's always makes the car loose a little torque at under 2000rpm on full throttle but how many times do you drive a car like that , full throttle 4th gear under 2000rpm?

 

Running without the plenum spacer will lose the normal gain in Mid range torque as well.

 

Also the dyno plots isn't your car stock versus you car after fitting the Abbey Motorsport performance package, we fit the parts then run the car on the dyno with the stock car ECU map then remap the car. So it is a before and after remap dyno plots NOT stock versus APP ( Abbey Performance Package)

 

Understood and thanks for the clarifications Mark, what you've said makes perfect sense. I would've liked to have added the plenum but as described above, it was a non-starter.

 

Anyway I've finally had a chance to try it out in drier conditions and can now detect more poke in 2nd/3rd @ 3-5k rpm. It's also nice being able to take the car up to 25mph in 1st without suffering the rough racket from the OEM exhaust - makes skipping that horrid 2nd gear a more viable proposition because the rev drop at that speed seems to be less severe i.e. I can make the shift holding onto 3k rpm rather than 2-2.5k.

 

DT

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Bud,

 

Ditch admiral as soon as you can.. The last 12 month have been a living nightmare thanks to them and my car was standard at that point, I'd dread to think what would have happened god forbid I'd allowed my car to breathe better..

 

Best advice I can give is. Hang fire on your mods, enjoy the car as it is stock till your policy runs out. Jump on with one of the various insurers on here who aren't as stringent and them reap the benefit of a fully allowing your car the power/torque/driveability Nissan failed to give.. :thumbs:

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