Craig, you don't sell these gauges by any chance ?
Maybe a huge group-buy is called for!

 

What exactly is this #3 big end failure? Is it throwing a rod on #3 blowing a piston or a bearing? I'm unfamilliar with the term "big end".

Something I wonder about it being #3 subject to what's really happening is the problem the North Americans have with the sequential fuel routing. Just about every turbo failure of an EJ25 here involves detonation on #3 and broken ring lands.

If the fuel is fed the same on turbo models then #3 is the last cylinder fed and gets far less fuel pressure. I measured an 8 PSI drop on my 2.5RS. This means #3 is the leanest and first to go.

-Michael

 

Crankshaft bearing.

[Edited by WREXY - 1/18/2002 11:30:01 PM]

 

On cars up to MY98 no 2 is leanest and no 4 the richest, after that they run pretty much the same, fuel pressure reg is right by no 3 ... means it will be seeing pressure as per the reg setting.

 

Iain

We have seen 2 failures with oil coolers fitted.

I haven't regarded them as relevant.

 

Cheers, Pete,
seems like an inlet temp and oil pressure & temp gauges would be a wise investment!

 

The problems with the RS-T (EJ25 with turbo added aftermarket and insane fuel pressure for the measly 280cc injectors to keep up) was that the stock pump/FPR couldn't keep up with the demand thus by the time it reached the FPR there just wasn't the volume / pressure available to keep up with the FPR's setting. Either way #3 was much leaner relative to #4 which is at the beginning of the sequential line. YMMV.

-Michael

 

Above 150 the bonnet was arcing quite noticeably - thought it was only on the safety catch at first!

This was leading up to the engine failure when abroad a couple of years ago.

 

With all these comments about under bonnet temps etc, should the vents in the bonnet have the covers removed? surely these were not put there just for looks! I removed mine when i bought the car, have had no problems with water on electrice etc.
Keith Sti v6

 

Erm ... interesting (although sad: warning, shocking pics of failed engine ) that the MY01 does not seem immune to the N°3 problem:

Read & wheep : http://www.impreza-rs.com/forums/sho...hreadid=137903

Not for the faint of heart ...

Check out the remains of the bearing inserts/shells ...

Theo

 

Theo,

I thought this one is blown because of very lean mixture (the owner of the car said so). He did fit an VF22 and lots of other goodies, but forgot to upgrade the fuel pump and/or injectors. (who are 420 cc at the new one)

He knows very well the cause by himself!

Mark Verhoeven.

[Edited by EMS - 1/24/2002 3:37:52 PM]

 

Mark, yup, I agree, he's very cool about it and is not trying to blame some mythical reason for the failure.

Just put the link here for the great (well, not great, but you know what I mean) pics And because I wondered if his case is an exagerated version of the n°3 pickup problem we see on stock cars.

Still, the real *reason* for this case is not clear to me... going from a normal engine to a 1800° EGT nuclear reactor in about a second (his Knocklink didn't pick up any det before the meltdown) ... there has to be more than just running slightly lean surely ?

 

you can make a charge temp sensor setup incredibly cheeply by buying one of those £15 digital temp guages from places like RS components. Just remove the plastic shielding from around the thermocouple then dangle the thermocouple into the airstreem after the intercooler. It's acurate to 1 degrees C.

A real cheep way of getting a max temp reading is to buy some AP racing or Think Automotive temperature strips and stick that to the intercooler. I use these on my water system and oil filter to give me a max reading obtained. I also use these on the inlet and exit side of the intercooler on my track car. I have seen 105 degrees C on the exit! The ECU on my car backs the ignition off enough to save it from det but it is the ultimate Pectel Map for the cossie i use, The drop in power is huge.

Getting a temp reading isnt hard.

 

I often do high speed for around one hour ( 200 to 240 Km/t - 130 to 150 miles -,during night time driving in Germany)

Car is standard MY99 Steel bonnet, from around 210km/t the bonnet start to bend upward and wobble a bit. First time I stopped to check , but everything was OK.

If this disturb the airflow to the IC, what about fixing the bonnet with two of those rally fasteners going trough the bonnet.
(I do not know the English words for those studs)


I'm now running with a Dawes MBC on 1.15 bar, but plan to go back to standard boost, before my next trim from Copenhagen to France next month. Just to avoid any blow up

Lars

 

Hi
Very Interested in your views and comments so far.
The engine went on my MY94 WRX a few weeks ago.
Alloy Bonnet - Full Exhaust System (with Cat section) - HKS Induction - HKS Dump Valve.

Posible Causes

1. I have an alloy bonnet. I warmed the car up and then sped up onto a motorway for about 15 seconds.

It was a very very windy day and the bit of motorway I was on curved and I was moving quite quickly

After about 10 -15 seconds (because of the weather conditions)I racked the speed back down to about 70mph (80 max) for the rest of the motorway journey. Noticed the problem after meeting Andy Tang at the end of the journey.

I to have noticed my bonnet flexing at speed especialy on windy days. Was airflow to blame?

2. I had an oil change (assured that high quality syntheic oil was used)about 7 weeks before it happened. Had done a fair few miles in those weeks. Would expect it to go a little sooner than it did if this was the cause. (4 weeks 1000 mile ish)

3. ECU was set up by a dealership to make sure that it would be happy on 97ron. I don't feel this has anything to do with it.


The engine is being stripped down this week by Dave West.
I will let you know what he finds and post the info.
Has anyone done more research into airflow?

Cheers
Steve

 

P.S.
People have mentioned removing the covers behind the two additional bonnet vents earlier in this thread. Will this do any good? Will it let water in and would this do any harm? Should I remove them when I get the car back?

 

Hi all,
Just to add my pennies worth,I just happened across this web site in Australia,it appears that due to the the way the fuel
pipes are in series to the injectors,number three cylinder doesnt get consistent fuel pressure hence it runs lean!!
Take a look yourselves and make your own decisions.
http://www.ravensblade-impreza.com/index1.html
Regards
Simon

 

In addition to above post go to page in top left corner click on all modifications,then fuel rail mod
Simon

 

Ah penny drops, this has been well discussed as well (oh search where are you). To summarise my own findings, Up to and including MY98 No 2 runs lean, No 4 runs rich and nos 2 & 3 are similar but "correct". MY99-00 all cylinders run at or about the same afr ie "correct". Theres a deal of thought around that the length of fuel rail etc causes the pressure to be low adjacent to no 3, but since the fuel pressure reg is right by no 3 and that is controlling the pressure I fail to see how it can recieve lower than design pressure, other cylinders may have slightly more than design spec but thats not what is being inferred here. Notwithstanding several of us have installed oil temp probes directly above no 3 cylinder as this was reported to run hotter in oil terms but, on my car at least, it doesn't, in fact same temp as when I had the probe in the sump.

Simonzzr, I see the relevance of your other post.

 

Bob,How have you measured this to come to this conclusion? (just curious)

Matt

 

Can the standard fuel pump supply enough fuel to meet the pressure regulator set point at full power and boost ?
If there is an 8 psi pressure drop across the fuel rail then to maintain say, 30psi static + 15 psi boost + 8 psi backpressure total 53 psi at max flow rate ?

cc

 

Done a few high-speed runs and...

You don't have to be an expert to see that the standard top-mount intercooler is going to get starved of air as speed rises. Just look at the bonnet line.

CraigH has mentioned that his bonnet visibly bends upwards at very high speed, which can only make the problem worse. That's an STi isn't it? With alloy bonnet?

At Bruntingthorpe I saw an indicated 150mph-plus a few times. Car steady as a rock, bonnet absolutely not bent. Mines a UK00, with steel bonnet.

For those that have logged the cars/failures, is this a high-speed alloy bonnet problem?

Richard.

Edited to add that if the bonnet distorts significantly, the bonnet/intercooler rubber seal will be broken, making the problem worse.

[Edited by Hoppy - 2/3/2002 7:55:08 PM]