like some help on this one please, i have the prodrive exhaust as part of the ppp pack and soon to be re-mapping etc, wondering if to do this or leave the origanal one on. what would be the bhp gain by fitting the 3" decat one and also will it fit on to the turbo without any problems fitting it.
i pressume the prodrive one is 2.5" and wondered where the extra space for the 0.5" comes from when it comes to fitting it. any help will be great as im sure many of you have 3" systems

thanks............. hardsy

 

I don't know the technicalities with regards to the BHP, but personally I would leave the 2.5 one on. I think they look and sound more "rally" as opposed to "Impreza wide boy". This is of course a personal opinion and I'm sure many will disagree.

I would imagine the power gains will be marginal but I'll let the experts on here wise you up to that.

 

The Prodrive back box is quite restrictive and the map is mapped on the safe side so my trusted tuner tells me. A change of exhaust to a good quality 3" system and remap could see a jump from 300 bhp to 320-340 bhp (if its a STI). Give a respected tuner a call and see what they say .

Wolfie.

 

what system would you recomend.

 

Depends on how deep you pockets are really. Milltek, Roger Clark Motorsport, TSL pulse extraction system are three that spring to mind however these are expensive but I suppose you pay for what you get. I think there is a group buy on the Milltek exhaust at the moment here on Scoobynet.

Hope this helps.

Wolfie.

 

Most peeps think that the backbox makes no difference to bhp. not so said Andy F when he remapped my car a couple of months back. He reckoned I could have gained a further 10bhp or so if I hadn't had the Prodrive WR backbox (based on his own experiences).

Still, it is "stealthy".

 

thanks for the replts chaps been helpful. i have spoken to a tuner and had a quote on a re-map, rc induction kit and milltec system(dont no weather it is 3" or 2.5"
£1065. is this reasonable.

 

right then heres a strange one.

I have emailed the top tuners in the country regarding a PPP'd 03 STI.

Basically i wanted to know what sort of gains i would get if i just went for the Ecutek remap and nothing else.

The response i got is quite interesting...

Change the exhaust completely..!!

A search on here first reveals that these tuners regard the prodrive 100 cell cat downpipe as good as any de catted aftermarket version. Yeah i thought thats excellent.

Its a different story when you contact them via there websites tho..!!

In one responce i was told that PPP stands for "**** poor performance" others simply state that the high flow cat is just not up to the job of giving any real improvement.

I can only assume that the tuners themselves come on here... (scoobynet) and their staff answer the emails and just tell you that xyz is needed cos if you order then they get a bigger pay packet.

any tuners care to comment on the ppp downpipe??? (I wont name and shame on here.)

However hardy555, save your money and buy some standard but ported and wrapped headers with up pipe and nip off to get it mapped. That should see you with 335+bhp and similar torque.

 

I'm pretty interested in some comments too!

From reading posts on Scoobynet I was under the impression that the PPP exhaust system was quite good, obviously not as good as a full decat, but pretty close.

After a recent turbo upgrade and remap I got 360bhp () while retaining the PPP sports cat, centre decat and Afterburner backbox. Apparently I should have achieved a figure more like 380bhp if I went for a full 3" decat system.

So where is the restriction in my system? The sports cat, or the fact that I need an extra 1/2 inch on my pipework?

 

you will get a better low down response with a 2.5". A 3" system will allow you to rev more freely higher up the rev range.
I have run both, both being Millteks and both have been great systems

 

where would i find these wrapped and ported heders and what sort of money are they.

 

Is that right?

I always thought from reading & listening to others that the 3" will spool quicker, as there's less back pressure.

 

lOOking around £400 with uppipe. Mocom do them and a few others. I would consider the GT Spec Gen2 headers if thinking of tinkering with them.

As for your exhaust. A 3" decat system will run you around £700. Scoobymania do one as well, that's not been mentioned already.

You could also have a custom exhaust made for the same price. You get to choose style, exit, tailpipe and they will make it as least restrictive as possible.

 

Stay away from aftermarket versions, there are a few that work well and dont have any reported problems but they cost 3x as much as a standard set ported & wrapped.

PM a user on here called "Harvey" he does them on an exchange basis, your old ones, for a set that he has already completed. (he sends you his, you then send yours to him so theres no car of the road time for long periods.)

He's 250ish for the headers ported/dressed/wrapped exchange and can also do a new uppipe suited to the ported headers which is also wrapped... cant recall price but its very reasonable.!

 

i think so - am sure others will confirm one way or another shortly

 

to get the optimum performance from a turbo charged engine, you need to get rid of the exhaust gasses as quickly as possible (as opposed to a N/A engine, where a "bit" of back pressure is positive.
the prodrive exhaust (at 2.5") is way too restrictive for serious gains, and you should go for at least 3" straight through, dont put a 3" back box onto a 2.5" centre pipe (waste of time due to the bottle neck effect)
and decat is the way to go (if your after performance)

in my oppinion, hayward and scott make the best exhausts, and ive tried loads.

good luck with your choices.

 

so is it best to do the exhaust or headers as i cant really afford both aswell as getting rc induction and remap!!!

 

Best to save up and get all mods done in one go really, but if you are eager, get the cat back exhaust fiited first (no issues with running lean/rich etc) then the decat/sports cat/headers and remap in one go.

 

I think the question you need to ask yourself is what power do you want to achieve?

If you want over 350 bhp you will need a bigger turbo.

If you are looking for somthing around the 330-340 mark then leave the standard PPP exhaust on there...

Ported and wrapped headers/uppipe will improve your spool up and give more power than ANY new exhaust* be it 2.5" or 3"( * as long as you have ppp downpipe already)

Also be advised to change the standard spark plugs for a set of colder grade versions. i.e NGKPFR7B's Before the remap.

Rob

 

i agree with most of that rob, but in my experances, the 3" de cat exhaust made significant improvement over fitting headders, i used equal length hedders on my my02, and didnt get any significant improvement with that mod "alone", and i lost the scooby burble.
for me the first mod, has to be the decat exhaust, and i did not rate the PPP at all, when she was mapped, pat h, ripped it out (the ppp circuit board) and chucked it away, and i binned the exhaust also.
overrated/over priced, and you can do so much for your money.
just my thoughts.

 

I'm on the understanding that the PPP map is simply a locked ECUtek'd map, you sure he removed something physical?

hardsy555.. have a look in the tech section. you'll find a few threads in there showing from lads expressing there thanks to the mapper used and showing rr graphs and details of mods fitted.

Heres a thread that might be of interest as well.

https://www.scoobynet.com/scoobynet-...ti8ppp-uk.html

 

PPP is indeed a generic map not an additional part on newage ECU's. I would be tempted to retain PPP exhaust and change headers for Harveys ported and wrapped OE ones which are best pound for HP kit u will ever buy! Stupidly sold mine for £100 when I sold the WRX instead of waiting for warranty to run out on my STI and putting them on it! Would imagine a good mapper could get 335 -340 bhp. Would reckon anyway that the standard STI turbo is only good for 350 bhp anyway. U could always do the job properly and get a nice TD05 18g on it then get Andy F to work his magic!!

 

what is this about only getting 350 tops then. i have seen proof of 376 on the standard vf35.
so with a good 3" system is a 15-20bhp achievable with remap on the ppp

 

VF35??? you have a bugeye then do you?

a VF34 is fitted to blobeye cars (MY03 onwards) its a ball bearing type.

VF35 has a little less power potential than VF34 but spools up a little earlier.

I've not seen a VF35 make 350bhp.

Rob

edited to add the reason a the VF35 spools faster is due to its smaller exhaust housing (p15) the VF34 has a (p20) much bigger.

 

sorry, its a vf34 its an 04 (53) sti8.

 

thats ok then!

VF34 should be good for upto 360bhp.

 

RUBBISH, where do you get your information from????
ask pat h, or any of the serious mappers, on bug eye cars with the PPP added as an aftermarket sale a phyisical board was added (the ppp bit)
pat h removed this from my car and chucked it away.
its about 6" long by 4" a pcb board containing chips etc.
its soldered in on top of the ecu.

 

Also, i was under the impression that back pressure was needed in the turbo system to prevent over boosting. Having moved from a Supra i know that anyone de-catting one of those then needs to fit a restrictor ring into the exhaust to stop the turbo shredding itself.

5t.

 

As i said in your other thread asking about power, yes that's possible, but only with addictives. Said car runs a methanol mix.

If you're not planning on changing your turbo ever, just remap the PPP. If there's a chance you'll go further, then the exhaust & headers would be a good choice.

3" decat £700, Ported or Gen2 headers £400/£450, walbro fuel pump £80, remap £650

You would benefit from also:

Induction £200, Plugs £50, 3 Port BS £120

 

thanks gaz you seem very knowledgable. i just want to make sure i know whats going on with my car when it goes in to have all this done and get the right bits for the right money if that makes sense.
if i was loaded then i would just take it to a mapper and say i want 400bhp and just do whatever you want to get there but im not....so i cant.