Reliability and Mods

[STi_Bandit]

As you all know iam planning on doing some engine work to the car, handling mods iam not to worried about its the Engine mods iam a wee bet unsure of, on the forums you read cars running at over 300 - 400bhp my wonder is long term how long the engine, gearbox will last at that kind of output before such time as lossing poneys or imploding.

You can take P1's as an example in standard form no mods you can expect to be replacing the bottom end aroind 40,000 miles. So with an STi modded to 300 - 400bhp can you expect the engine to one day so to speak give up the ghost.

Martin

[Gumball]

I think if you have a car with a standard engine (internals wise) then you really need to keep it the short side of 380 or so. As seen recently the standard tmic for example only really likes to operate with 350-360 or less before it starts causing heat soak/det issues.

Really the furher up the scale you go on the cars the more you need to have in the reserve finance wise incase it all ends in tears and a blob of chocolate. Ie having the money to replace something thats gone bang, like a piston or the likes.

The standard STI engines are fairly strong and this is overlooked but in honesty i would suggest not trying to see how much it takes before it squats its inards out all over the tarmac.

As far as i know, the highest figures a standard 2 litre engine has taken in Europe, without having forged pistons, rods and such like is 452bhp and 372lbft.

Scoobymania were or probably still do a kit for 8k that will give you these power figures.

Perhaps 340bhp/340lbft would be the ultimate balance for power, speed, and peace of mind??????????????[:^)]

** forgot to mention the bottome end**

If you change your oil every 3000-4000miles depending on how you drive your car then hopefully there shouldnt be a problem with this going. An uprated oil pump or not holding the car flat out on a private track at 150mph will also help this to stay alive.

[RA Dunk]

i think about 350 BHP (ish) is what the WRX gearbox is rated for but

even with that and similar torque you still have a pretty quick road car

[STi_Bandit]

The Ultimate goal for the car is a fast road car, it was going to be PPP but for better power gains ill be putting on my own aftermarkect parts, All i want to be sure of is the list ive planned for the engine that ive not missed anything out that will lead to premature failure of an engine component.

Martin

[Gumball]

maybe post the list then people will be able to advise you or not what to get from it?

[STi_Bandit]

The works to the engine will be carried out in two phase or as i like to call it when ive saved enough cash to purchase the next bits. Iam pretty sure these wont put that much stress on the engine only really allowing it to breather better i hope.

Phase One Engine

TSL Thundercat Sports Cat downpipe

TSL Classic Sentre Section

TSL Group N Back box

TSL Green Filter Group N

Phase Two Engine (Four months or so later)

Walbro 255 Uprated Fuel Pump

Andy F Remap

 

Martin

 

[p1ggm]

dont think you will need the pump with just that fitted, i am still running the standard one, althou i do have a 255 sitting in the spare room

[rapidcossie]

what makes you think a p1 only last for 40k?

[STi_Bandit]

I dont know the in and outs of the P1's and there engines i know that they are very suseptable to knock and lesding to the big end going. Perhaps someone with a P1 would be able to tell you more about the engine. I looked at a few p1's and they all had recent engines at the 40 - 50k mark

Martin

[p1ggm]

mates p1 just blew up a few weeks ago, think its got under 40k on it

[rapidcossie]

P1's run very close to det in standard form.

 

i know guys with P1's both modded (correctly) and both over 40k no hassles...

 

every P1 needs a remap or it is a time bomb...

[STi_Bandit]

Ive seen a few P1's with the standard mod of a knocklink to moinitor the Det.

Martin

[iain_ogston]

I spent a lot of time discussing practicality and reliability versus performance with my local engine builder before my car had it's recent rebuild.  The options on offer stretched up to 450 bhp, and my main criteria were that I wanted a car that was amazingly quick, but which I could take to work every day without it blowing the engine.

The standard STi engine is very strong and has lighter forged pistons than are standard on a WRX.  That's why I replaced my WRX 95 block with an STI6 short engine. A few more internal tweaks such as upgraded bottom end bearings, cams and lifters means the engine revs higher but does it safely.  An upgraded oil pump has been fitted to ensure the engine gets a good supply.  The heads have also been fully ported to allow increased gas flow, and they are held on with upgraded studs and high performance metal head gaskets, which also have the benefit of altering the compression ratio slightly.

However, there's no point in upgrading anything in the engine until the ancillaries are correct. Sort out the exhaust system - equal length headers, decat up/downpipe and centre section, combined with a high performance back box.  You need this to allow the engine to breathe properly.  If you're going to remap with increased boost you probably want to upgrade your fuel pump (I needed to cos of the age of my car), fit a fuel rail pressure stabiliser and bigger injectors (which can be fully utilised as part of the remap).

Once you get to bigger power your clutch will struggle too.  You'll need minimum of an organic clutch (rated to about 400Nm) and it's worth changing the flywheel when you're in there for something like an STI motorsport 5kg version - I found the flywheel makes a huge difference to the characteristics of the engine, making it much more responsive (both through the revs and you get a bigger drop off between gears, which is useful with a close ratio box like my RA)

If you're getting an Apexi ECU then it will monitor knock for you and the check engine light flashes when it detects the onset of knock, so you can retard the ignition timing a bitty to avoid engine damage.

Basically you need to speak to your local expert and set a target - what power do you want to run at the end of the day? Every part you fit to your car will then be based on that target and this means the car will run higher bhp but it won't suffer reliability problems since it's been done properly.

[rapidcossie]

a drop in compression ratiois the safest way to run higher boost...

 

not many people seem to do it on here tho