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hi guys i have a 2003 impreza wrx prodrive, current mods are cosworth air filter, raptor backbox, afterburner bore section  and decat up-pipe. im looking to get decat downpipe and uprated fuel pump this week, so my question is would i need a remap as soon as i get these 2 bits fitted and secondly is there any other mods i should get before a remap, cheers

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Most mappers would recommend fitting a pump prior to mapping as upping the boost requires more fuel and can put strain on a old pump .

You can fit a decat and drive off boost but you should remap asap ,as the boost controll system and oe settings will struggle to keep the boost levels in check . Due to the less restrictive catless downpipe and this could cause the boost to come in earlier or hit higher peak values ,which the oe fueling map can't compensate for (running lean/ fuel cut due to overboost).

 

Think the ppp wrx is supposed to run 265hp standard and use the tdo4 ?

If so you probably won't see a great hike in hp ,as the tdo4 generally maxes out at 290 hp ish but you should see better drivability (boost coming in sooner ) and economy off boost .

So unless you want to fit a bigger turbo and injectors to break the 300hp mark , id add a oil change and spark plugs to the mod list , unless they've been changed recently  

Best of luck with the remap , fella 

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Yes I definetly want to break the 300hp mark that's my target, what turbo would you recommend and is it just a straight swap or is it more complicated, cheers 

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Double check that you've got a tdo4 first , by either googling it or looking on the coldside (silver part of the turbo) as I'm not 100% up to scratch on my blob onwards spec . 

Not sure if the ppp has a precat in the up pipe ?

 But if so either a aftermarket up pipe or sti up pipe would be worth fitting while doing the turbo ,as it will help spool .

Most front entry subaru fitment single scroll turbos are a straight swap but the usual route is either a tdo5 (cheapest ) or vf35/vf34 or vf43 .just beware of cheap copies and try to get the water lines , oil lines and banjo bolts with the turbo .

Your standard injectors should be good for 320 hp ish but sti "pinks" would match the hp of the turbos above @ about 330 to 350 hp ish .

 

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ok i'll have a look in the week just to double check what iv'e got, thanks for all the help much appreciated, i'll speak to you in the week

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Steer clear of cheap new turbos ,bud .you definitely get what you pay for 😉

Second hand subaru fitment tdo5 16g  (Mitsubishi made) cost between £150 to £200 .

Vf 35/34 /43 expect to pay around £350.

Sti pink injectors are about £100 2nd hand .

Try a reputable breaker ,like matt baker at mbdevelopements on f.b if you want to keep the cost down and buy second hand .

The only new "cheap" sub £800 turbo manufacturers that some people have used is kinugwa and mamba but depending on who you talk to , some say they're rubbish too .  

I only have personal experience with a tdo4 (made 265hp).

Paid £50 for a top entry tdo5 (made 347hp) 

Paid £150 for my current apssr40 (made 360 hp) 

But i do have a lot of supporting mods 😉

 

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so just had a look at mine, it's a TD04 20g. what would you do if you was me and was aiming for over 300bhp

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Vf35/34 and pink injectors is the usual route ,as thats what's fitted to bug and blob sti's. 

Once you've fitted a bigger turbo and been remapped you might end up having to renew the clutch ,if its the original and worn it might start to slip shortly afterwards .Also might find you need to upgrade the brakes to reign in the extra ponies from a bigger turbo .

So really it depends on budget and what you want from the car . As a remapped tdo4 could get you a quick spooling 290hp (ie faster in 1st to 3rd) , which might suit your needs more than 330hp thats not as responsive. 

Think my tdo4 was a tdo4 L but that was on a 97 uk turbo .

 

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No problem bud,  just try not to get too hung up on pub figures.

A friend had a type r with a gt30 that made over 400hp but my £50 td05 at 330hp used to beat it hands down . Mine hit 1 bar at 3k and pulled to the red , his hit 1bar at 5.5k and lit the tyres in 1st to 5th at 6k .😉

 

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ok will do, while iv'e got you here iv'e got a quick question since you obviously know your stuff, had a power problem for a few weeks now which seems to be getting worse, put your foot down in 3rd gear and as soon as it hit 3k revs it felt like someone was pressing the brake, i know the power is there but can feel it holding back, hard to explain but its as if you put your foot down and there's 50 people grabbing your rear bumper pulling you back lol, it's now doing it in 1st 2nd and 3rd, was told coil packs but had them checked and there all fine, any idea's

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Could be numerous things , no ecu codes ?

Are the spark plugs due soon , colour and condition can help pin point a cylinder misfiring or general running issues . If they are due a change ,most switch to heat 7's when modified .

Do you have a boost gauge ? 

A boost leak could cause a lack in power. 

I'd definitely get it running right as standard before modding or mapping it , bud .As it might save a lot of dyno / mapping time 😉

 

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i checked the codes and nothing came up, spark plugs were changed around 6 weeks ago so wouldn't think it would be them, i do have a boost gauge but haven't noticed anything wrong there, will definetly get it sorted before i start changing things, decided to go for the vf35 after having a look around, what does it mean when it says 16g or 20g,  would it be a straight swap with mine or would i need to modify a few things to get it in

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Boost solinoid clean and ecu reset might be worth a go ,as well as checking if the plugs are all the same colour and the right colour .

I don't actually know technically whats the "g" stands for but its a way of measuring the turbo compressor (coldside) wheel, 16g is stock size and 18g is slightly bigger. 

Ie .  ...

A tdo5 16g (stock subaru) will spool earlier but flow slightly less air at say 1 bar .

A  tdo5 18g (aftermarket) will spool a bit later (more lag) but will flow more air per minute at the same 1bar . So it would make higher max hp but higher in the rev range and be less responsive (laggier) due to having a bigger 18g wheel 

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Could be getting fuel cut if its overboosting with the decat up pipe and exhaust, i had that before mapping and it was like someone putting all the brakes on suddenly 

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cheers for the help guys, gonna have to find out what it is before i start changing things, would upgrading the spark plugs to performance one's make any difference? there just the normal cheap one's that were put in when it was serviced a few months back , read on another site about someone losing power so they upgraded there plugs and it solved the problem

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Upgrading the spark plugs is well worth it as they will give you a stronger spark and you'll probs need them for when you get mapped as upping the boost pressure can blow the spark out on normal plugs then you start to get misfires which would mean going away fitting new uprated plugs then having to go get mapped again which all costs pennies 😉👍

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so finally got round to putting them new plugs in last week but no change, on my way back today the engine management light came on so plugged in the code reader and has come up with cylinder 2 misfire, where should i go from here,thanks

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