Hi does anyone have any opinions as to what bhp levels a 2.5 inch full decat system on a sti bug could support.

Looking to upgrade my turbo to a harvry or a forrest 05 20g and need to know whether im going to need a 3 inch exhaust.

ive researched this on here and some people reckon 350 and some say 400.

dont want to go to expense of getting car all done then be dissapointed with results for the sake of a new exhaust system

any help would be great

 

What other mods and how old it the 20g?
I would say 3" bigger flange and if you have a ppp exhaust then just de cat to h& s. And who is mapping? Tmic ot fmic? May be good to get a set of headers and make sure there new not old ones like I had to find out.

 

hi sorry , car will have a new 20g or hs 380 , ported headers , a rcm 3"to 2.5 " decat downpipe straight centre and a afterburner vortex , with a fuel lab mini and will be mapped by race dynamix and has the sti top mount and standard pinks

 

a 2.5 system is more than capable of 450bhp,over that i would opt for a 3".

 

With the mods u just put up and running clean v power your car should make 350-360 ish your exhaust system should be fine but your 550 cc pinks may be getting maxed out. Sti top mount cool but don't put a dv on it as the af 20g is sluggish so with the original re serk that turbo spins better and should be less sluggish.

 

Sorry to resurrect this but I have a similar question as to what would the same spec achieve with the ppp sports cat in place and with 650cc injectors? And is there a better option of turbo? Also would an RCM induction kit have much of a benefit over a green panel filter?

 

Hi there

depend if you are running FMIC or no,if yes RCM kit is best without the doubt.

Better option for turbo,yes and no,better will be SC46,but this turbo you hardly find used.20G is great turbo and with supported mods you can manage around 380-410bhp


About the exhaust,you are running 2.5" or 3"?


Jura

 

Sorry I should have given you more details.

Bugeye Sti Type Uk PPP
Short centre, long centre pipe and afterburner BB 2.5" with PPP sports cat in place
TMIC
Green Panel filter
And remap @TSL

Cheers for the help Jura as I can't find what I'm after through searching.

 

Really depend now from mapper,but i would imagine somewhere between 370-390bhp,but i cannot guarantee this..

My biggest concern is 2.5" exhaust and TMIC,i've seen few cars with 2.5" and TMIC make lower power than after swapping for FMIC and 3"..

Most people said is not restrictive up to 450bhp,but this depend on make of exhaust.

Methanol will be great addition on your car,i would recommend also.


Jura

 

380-390bhp i'd be happy with but for the outlay to only get 370 or under I wouldnt be too impressed.

How much is mapping these days as i last had a scooby when it was tek2 tek3 etc.... and it was about £500+

Is using methanol an expensive game?

 

Hi there

Duncan@Race dynamix charging for remap £350 or Graham@EngineMapper charging £225 both using OS,same result as EcuTek for less money.


Methanol is not expensive game,you can put to your full tank of fuel,just have look for Methanol suppliers(Jenychem is good http://jennychem.com/) or you can buy methanol injection kit..

Jura

 

Wow! That's cheaper than unleaded! I had no idea. Thanks Jura your a star!

 

Andy Forrest is running a 2.5 Hayward & Scott system on his 500bhp Spec C.