A few questions about my rex

[Guest]

Hi guys, im new to clubsub this is my first post

Iv got a 1998 wrx sti but dropped a valve head last summer and the engine became a throw away so am now running a brand new EJ25 forester STi short block with second hand 2.0ltr heads.

When i brought it: http://img594.imageshack.us/img594/3051/ip2z.jpg

What it is today: http://img593.imageshack.us/img593/8201/dsjfh.jpg

Photoshop lowered cuz its high as a kite! : http://img560.imageshack.us/img560/1731/evoeta.jpg

I'd love to go crazy and throw thousands at the engine bay but im not that financially blessed.

Just looking for your opinions on some things i can do to gain a bit of extra power/acceleration without destroying another engine and without breaking the bank account.

Everything running gear wise is totally stock apart from the 2.5ltr sti block, still using the VF24 turbo from my old engine etc

It's running 14.5psi at the moment and im told by Sublab that it wont handle more then that without causing damage.

I also enquired about purchasing a second hand aftermarket ecu and getting a tune but they told me its likely to put alot of stress on the engine and i should be willing to fork out for another one

Is getting a few extra HP out of an aftermarket tune really that bad for it?

Look forward to hearing from your opinions

[Timmah]

First off, welcome!

What actually has been done to the car? Other than the new block?

For a little more HP you could:

- Oversizied under manifold intake

- Zerosports intake pipe (Or larger diameter pipe after the AFM)

- Remove the intake resonator and pipe up a better intake from the guard

- Get a pod and a proper cold air box

- De cat the exaust

- Get a 2.5" or 3" turbo back exhaust

And then probably an EBC to hold boost better.

Could try remove stuff to make the car lighter

All depends on how much you're willing to spend..

[Kiwi_Fozze]

ej25 foz sti block.... i'm fairly sure the pistons should be able to handle it, unless they put some cheaper ones in? i'm not up to speed on the 2.5's....

sounds like a bit of a fun ride!!!! and welcome!!!!

[Stoffa]

I think the reason they told you not to take it over 14.5 psi is your running the factory ecu, that would be the first thing you should change as your running the wrong fuel maps and ignition timing for a 2.5litre engine.

Personally I wouldn't feel safe driving it at all untill it was tuned properly for that engine, but in saying that I have heard of people running like that for a while without noticing any damage.

You could always get it checked on a dyno to make sure its safe. Dyno days are usually only about $100, just tell them the story and dont let them rape it.

You could get something like an SAFC 2 these can be picked up pretty cheap second hand and let you adjust your fueling to a point by "tricking" the ecu to thinking there is more air going into your engine than there is and your factory ECU will give more fuel to match. They should be tuned on a dyno but can be done on the road by someone who knows what they're doing

[Pappu1]

turbo back exhaust

vf22

front mount

link type ecu

retune

that ought to get u running very nicely and its not a very big spend for the performance upgrade

on a more stricter bugget

turbo back exhaust

vf22

boost controller

then set it to a safe level where its not knocking and afr still ok

(dyno tested as well)

the reason i say bigger turbo is that the vf24 wud be running outa putff on the top end with the 2.5 litre block

but u cud still keep it and just do a turbo back exhaust and boost controller and set to a safe level as a start off point

[Guest]

Thanks for the replys guys some good info in there.

Nothing has been done to the car apart from the new block and appearance mods, other then that its totally stock.

I think ill start off with the turbo back exhaust iv been meaning to get that for some time

What are your opinions on plumbed back external waste gates or external waste gates in general?

Sounds like a proper tune is definitely in order then, could anyone recommend a cheapish aftermarket ECU suitable for my needs? doesnt need to be a link G4 extreme obviously...

And maybe opinions on EBC's, I brought an HDi subaru specific EBC but when i had it installed it was faulty, eventually had it replaced then sold it because i thought i might stress the engine too much (then my engine died )

Depending on how damaging it would be to my engine, i dont think id want to run higher boost so should be alright with the VF24, Unless anyone has a VF22 going cheap?

[Stoffa]

You could use a possum link but they're pretty old technology now, you'd get a much smoother more responsive tune out of a G4, and once its properly tuned you would have alot more power anyway and you wouldn't HAVE to run more boost.

Also with a G4 they have a VERY good boost control setup on them now so you wouldn't need an external electronic boost control

For a cheap option you could just put a P20 (same as a vf22) exhaust housing on your VF24 that would make it a vf23 and free it up a little. but any vf turbo on a 2.5 will just run out of puff and you boost will drop off at higher revs

[Guest]

Yeh I'd like to run a G4 but arent they an extremely pricey unit and more for high street performance applications? And to tune the engine to get significant gains in power without upping the boost, doesn't that put alot of stress on the engine reducing its life? Which by the sounds of it running my stock 2.0ltr ECU, isnt going to be very long :-\

Please correct me if im wrong, I want to learn more about my car and its capabilities

[Guest]

welcome love how the car looked when you bought it! the rims you put on look awesome though just not a fan of the lights but thats just my personal taste

[sultan]

ok, there are several limiting factors here if you want to make power safely.

- the stock engine internals are very prone to damage from detonation as they are not forged and have been known to crack and melt in even stock setups

- your stock 2.0 heads are the wrong shape compared to the bore. there is a large overlapping area on the heads which causes a rise in compression ratio and also creates excess heat which promotes detonation.

- which head gaskets were used? oem headgaskets will raise the compression ratio even further again

so your motor itself is high compression, with high combustion temperatures, with pistons that are begging to melt. not a good combo for seeking power.

what i would do - not aim for a peak power dyno machine. you have a good torquey platform, roll with it. a vf22/30/34 td05 is a fantastic match for this, it'll be fully spooled before 3000rpm and you won't need to rev it out to get it to move. you'll still be able to make around 230kw up top but with huge balls down low, with the right setup.

you definately need to get a link and proper tune, it's an expensive mishap waiting to happen otherwise. get an electronic boost controller, don't waste money on doing an external wastegate setup your internal will be fine. do at least a 3" dump pipe std 2.5 mid section with a free flowing muffler will be fine. put in a walbro pump and do the parallel fuel rail mod and a fuel pressure regulator, try and find 550cc+ injectors if you can. front mount is definately for you, to keep those intake temps down which will aid in avoiding detonation. definately invest in an alloy radiator with big fans as these motors love to run hot. ditch your AC so you have better airflow to the rad

[Guest]

 sultan said:

ok, there are several limiting factors here if you want to make power safely.

- the stock engine internals are very prone to damage from detonation as they are not forged and have been known to crack and melt in even stock setups

- your stock 2.0 heads are the wrong shape compared to the bore. there is a large overlapping area on the heads which causes a rise in compression ratio and also creates excess heat which promotes detonation.

- which head gaskets were used? oem headgaskets will raise the compression ratio even further again

so your motor itself is high compression, with high combustion temperatures, with pistons that are begging to melt. not a good combo for seeking power.

Jesus! sounds like the crowd that put this engine together are idiots!

Im a carpenter by trade not a mechanical guru so i dont know what im doing but i figured these guys would, being subaru specialists and all, iv got to say im a bit worried, i've been running this engine for 8,000kms now + 5000km running in on 8 or 9psi and at that stage they did say it was getting some detonation but never mentioned anything about fixing it?

If i remember correctly they said they put in non-turbo head gaskets which are thicker then turbo gaskets right? so an even bigger squeeze space between the pistons and heads? Didnt sound right to me, running non-turbo gaskets in a turbo'd engine but like i said, i dont know the in's and out's so i just trusted them....

Do you think 2.5ltr heads and a new ECU are priorities? I want to get the engine running the way it should so that it lasts rather then putting more power into an engine that could die on its current set up.

Have they built me a lemon motor or what guys?

[kamineko]

maybe start looking for a receipt?

[rex-leggy]

they should know better putting non turbo head gaskets into a motor thats has detonation problems . or a turbo .

i would deff double check what they have actually done to the engine before proceeding

[Guest]

 kamineko said:

maybe start looking for a receipt?

Iv got the receipt for all the work they did but apparently because it was an upgraded engine there was no warranty on it, only a 6month warranty on their work...

And yeh for subaru specialists they sure don't seem to know what their doing

[jacsmiley]

first thing as sultan said is the ecu

get that first and go from there. you have to remember that the ECU doesnt give two shtts what motor it is controlling. it measures and controls accordingly.

a correct and propper tune wil actually put less stress on your internals while giving you an increase in power through efficiency alone.

the non turbo head gaskets could be an issue tho, but the compression can be compensated for in the tune.

me i would sort the brains and fuel (pump, injectors, reg etc) together, along with the usual exhaust intake mods etc etc etc and leave it as is.

[sultan]

there's nothing wrong with a hybrid motor, as long as all factors are considered and planned out. i have one myself, but there's a lot of money and development in it. in your case, a 2.0 would have been much better.

the reason you use 2.0 heads instead of 2.5, is that you won't be able to find any 2.5 heads, and if you do, they will be bloody expensive. thicker gasket is correct as this will help lower the compression ratio. dunno about the non turbo gaskets though.

the only absolutely necessary thing, is computer and tune. if you're doing any other mods though, do them first

[jacsmiley]

 sultan said:

the only absolutely necessary thing, is computer and tune. if you're doing any other mods though, do them first

+1

[kamineko]

 Gizmo776']

[quote name='kamineko said:

maybe start looking for a receipt?

/quote]

Iv got the receipt for all the work they did but apparently because it was an upgraded engine there was no warranty on it, only a 6month warranty on their work...

And yeh for subaru specialists they sure don't seem to know what their doing

sorry, i meant find the receipt to clarify the work done. hopefully its detailed

[Stoffa]

 sultan said:

- your stock 2.0 heads are the wrong shape compared to the bore. there is a large overlapping area on the heads which causes a rise in compression ratio and also creates excess heat which promotes detonation.

If the people who built it know what they are doing, they may have had the combustion chambers reshaped to match the wider bores, but anyone building an engine SHOULD have done all the measurements and be able to tell you what compression ratio its running.

I just had an engine built and all the info was written down on the reciept

[Pappu1]

if it was a subaru place then easily they wud have all this knowledge

lets see what they have stated in the the build (also perhaps ask them to clarify)

perhaps they did all the right things e.g. compensated for compression ratio etc..

find the details of the build and post up

im sure folks here wud evaluate and let u know if it needs to be worried abt

[Guest]

Alright guys heres the write up of the receipt, its not very specific to parts but it's all i have at the moment.

-Removed engine and LH cylinder head, head of valve broken, head, piston and cylinder damaged.

-Removed heads from forester engine

-Stripped RH head and all parts from damaged engine, checked and cleaned ready to fit new short block.

-Cleaned out aluminium pieces from inlet manifold

-Checked turbo condition

-Fitted new valve stem seals to both heads

-Swapped valve springs and keepers from original heads to second hand heads

-Fitted STI shims and buckets, check and adjust valve clearances and wetstone shims to suit

-Remove and clean engine sump, pickup and baffle plate.

-Removed and cleaned oil pump and oil cooler

-Fit parts back onto new 2.5 shortblock

-Fitted new genuine water pump, thermostat and cambelt

-Fitted new crank seal

-Assembled and fitted engine to vehicle

-Hooked up all components, changed oil filter, filled with new oil and anti freeze

-Pressure tested cooling system for leaks

-Run engine to operating temperature and checked cooling system operation

-Carried out road test and checked engine management operation all ok

Note: set boost levels to minimum wastegate pressure 6psi for engine run in.

There is no warranty on the engine as it is modified beyond manufacturers specifications, but as an MTA member we guarantee our work for 6months 10,000km

I may have been mistaking when i said non turbo head gaskets, they might have said wrx (non sti) head gaskets.

Really appreciate the input so far, cheers guys

[Stoffa]

just cleaning the oil cooler is a bit dodge, but ive heard of alot of workshops who do it.

You'll be able to see which head gaskets you've got, hopefully steel ones, just look on top of the engine where the heads meet the shortblock, head gaskets stick up

[Guest]

Well if i proceed with having a link ecu installed, can anyone recommend someone who knows what their doing with dyno tuning in the auckland area? preferably had tuning done with their car. And whats a ballpark figure for the cost of getting it installed and tuned?

[sultan]

possum bourne motorsport in pukekohe. tune will be about 800 or so i'd imagine. a brand new link g4 is about 1900, but you can find a possum link or something else for 500-1000

[Stoffa]

Garry Capper advertise to put it on finance, they now do alot of possum borne motorsports work, go on tick up get it done next week ;D