What sort of gain can I expect?

[len_beach]

I have a mk2 172 with a PiperX panel filter, uprated air feed (including removal of acoustic valve), custom stainless exhaust with small middle silencer and a remap.
Disregarding the remap, what sort of BHP figure would I be looking at with the filter and exhaust setup?
What would a decat give on top of that?

 

[Fred@BTM]

that lot, probablly 185bhp (ish)

 

[portal172]

What does removing the acoustic valve do?

 

[The Hoff]

It stops the stereo working correctly

Nah basically its a valve thats designed to prevent water/flies/crap finding its way into your airbox and filter, i believe its found in the lower intake duct below the airbox. Removing it supposedly allows for better airflow/engine breathing - although ive seen nothing to proove this as such.

 

[caymanr26]

ive taken that duct out altogether - it wasnt actually coming from anywhere useful so have just got the one duct now

 

[thedoc]

my guess is between anywhere between 170 - 180, remap & decat would add maybe another 10bhp. All speculative figures though.

 

[len_beach]

So with the exhaust and panle filter I'm looking at about 175bhp.
The exhaust, panel filter and decat about 180bhp?
The exhaust, panel filter, decat and remap between 185bhp and 190bhp?
Not far from the magical 200 mark.

 

[The Hoff]

Not that easy mate, the opinions you asked for are exactly that, and taking the RS engine to 200bhp without TB and cams is pretty much a non starter. 185 is very attainable though.

 

[Phill1978]

surley your assuming the 172 has 172bhp in this equation to start with ? most have 168bhp so i dunno if a exhaust + panel filter would add 7bhp, probably would with a remap, add induction for anther 3 when mapped and you could i imagine see 10bhp with a zorst, induction, remap (remap is the key though) but with just panel filter you could see 8hp.

so 168 + 8 = 175 or dependant on the power of your engine 170hp + 8 = a realistic 178bhp for remap, induction and zorst with the lucky ones getting 180/181 i would imagine.

 

[Phill1978]

.. but with induction i may add it would be in real terms about 183hp


get cams and althoughs other mods come together when remapped and then 195 would be possible.

rapido

 

[MarkM]

You are not really increasing air flow into the engine.

So IMO the mods will be providing better driveability and mid range (more important IMO) but not really any great power increase 180 tops.

To put it in perspective Haitch (user on here) got 196bhp (on a 172) with cams, IK, manifold work, decat, exhaust, fuel injectors and remap, may have been more mods but you get the idea. Although he did get a much more important 180lb/ft of torque.

 

[Phill1978]

dunno if larger injectors are needed tbh, but i imagine with cams and then adding some manifold work in i.e inlet you could see a good gain.

basically it aint cheap or easy, and its detectable mostly by insurance investigators so not like a turbo weasle with a hidden and switchable remap ala SPS2 revo code.

its better to strip the car for more performance imo and save up for getting it all done at once.

removing back seats and getting buckets in the front saves me over 30kg! equivelent to 7 extra bhp per tonne dont know what that would mean in raw bhp but it feels fooking quick removing weight from it.

 

[The Hoff]

Even quicker Phil if you starve yourself for a week and drink pentolax!

 

[gh172]

it feels fooking quick removing weight from it.

Totally agree that weight saving is the way to go. Rotational/unsprung weight in particular. Just saved 12kg unsprung by fitting SLs - and if you believe what you read that's equivalent to 96kg static weght, e.g. ditching the lardy driver

The only other thing I'm considering at the moment on top of my setup is Nick Hill's inlet manifold work - good vfm I reckon compared to a custom exhaust.

 

[172beast]

surley your assuming the 172 has 172bhp in this equation to start with ? most have 168bhp so i dunno if a exhaust + panel filter would add 7bhp, probably would with a remap, add induction for anther 3 when mapped and you could i imagine see 10bhp with a zorst, induction, remap (remap is the key though) but with just panel filter you could see 8hp.

so 168 + 8 = 175 or dependant on the power of your engine 170hp + 8 = a realistic 178bhp for remap, induction and zorst with the lucky ones getting 180/181 i would imagine.

Most have 168bhp to start with because 172 doesn't stand for 172bhp lol it stands for 172ps

 

[Phill1978]

Even quicker Phil if you starve yourself for a week and drink pentolax!

true but youve bought up all the supply`s so you can keep yourself free and easy for your clients.










thats what i heard anyways

 

[Ali]

that lot, probablly 185bhp (ish)

Thats generous.

 

[Phill1978]

Totally agree that weight saving is the way to go. Rotational/unsprung weight in particular. Just saved 12kg unsprung by fitting SLs - and if you believe what you read that's equivalent to 96kg static

im assuming you mean 90kg lighter cup + 6kg saving on the wheels.

i didnt need my back benches anyway and took em out + lugage bar = 15.5kg so im down from 1020 to 1004.5kg in the cup now, thats 105 kilo`s lighter than a MKII 172 and 6 all round lighter running turinis for unprung weight of course, i rekon you would need more than 10hp to make up the difference in power to weight for that lot on a MKII.

i really like the turinis they arent the lightest wheels but im keeping them on, the next weight saving is ditching the 22kg front seats and getting 6.5kg bucket seats, including custom subframes the saving from that will be around 10-12 on each side at most il be at 985kg.

money spent = £184 on each seat. not much compared with a new ECU £250-350, RR time £50, full exhaust £350-500 + full induction £200-350 etc..and the gains will be greater than those power mods.

 

[gh172]

im assuming you mean 90kg lighter cup + 6kg saving on the wheels.

No mate, I mean 1kg rotational weight is equiv to 8kg static weight. I honestly don't know whether that's true but it's often quoted. If it's correct then fitting SLs is equiv to around 15bhp on a std 172. Sounds good anyway

G

 

[Ali]

wat does a mk2 full fat 172 weigh?

 

[gh172]

1080kg isn't it?

 

[haitch]

i think the gains will be minimal but it is a good place to start, getting buckets and binning the spare on your full fat is also a good way to go to benefit those mods, my full fat is standard as i like my creature comforts and in these days of jealous vandals, attention from the law and the odd carjacking (pending on where you live of course lol) it doesnt stand out. Mark has just about got it but with headwork, also larger injectors, which are only needed if you are v'close or over 200hp,

 

[Phill1978]

1080kg isn't it?

nup.

the MKII 172 weighs 1110 kg (not much really)
MKII 182 weighs 1090 kg (20kg`s less due to no spare and kit)
MKII 182cup weighs 1075 kg or 1070kg ?
MKII 172cup weighs 1021 kg 89kg less than MKII
MKI 172 weighs ??? its not as light as MKI`ers go on about i think its around 1095 kg`s

as far as unsprung weight goes i heard 1kg = 1bhp of theoretical power gain, hence the reason i think the cup is quite a bit faster than the MKII172 and dare i say it a 182.
90 kilos lighter, 6+ kgs saving unsprung weight over 182wheels etc..

 

[len_beach]

The way I was thinking it was:
169 standard + 2 for airbox and panel + 4 for the exhaust + 10 for the map = 185bhp
Then a decat which would maybe add another 3-4.
I think my next mod may be a space saver wheel to lose some weight. Not sure what else I could strip out though without removing loads of luxuries.