Anders

Three cheers for Pat!

Pat would you have a rechip?

Or would it have to be a Motec, Pectel, Autronic or Link?

For what its worth my job means that I get to drive briskly all over the South East, and never had a problem in a JECS powered 22B for 50,000 miles (my and the Squires 22B)

Top sustained speed was 150-155 MPH in the cold of a Southern France night on the way down to Catalunia (not banging off the rev limmitter as even I knew it was a bad thing to do! Actually the last bit 150-155MPH took ages compared to the 140-150 MPH and so one realised that the car has limmits!)

NDT please visit my technical BBS

NDT

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:<HR>Originally posted by AlexM:
<B>
Did you get a look at your engine while it was in bits? Did it show signs of having spun the bearing shells as has been suggested in this thread? Was it rebuilt with oem rods and bolts or something a bit better?
[/quote]

Alex
had the engine rebuilt with stock rods and bolts (but Cosworth pistons).
I've got all the trashed bits and pieces in a friends barn....(just moved house) so I'll check out whether the bearings spun or not next weekend.
Nick

Stelios

A *very* compehensive analysis Pat.
I thought only us greeks could spell stoichiometric correctly though!
Well its oil cooler time from me guys as its the the one with the highest Benefit/$ ratio

pat

Stelios,

there's you greeks and us geeks that can spell stoichiometric properly (having said that I'll probably make a typo, d'oh!)

Anders,

There are a few good 'uns out there, and no I wouldn't have any remap that I couldn't check and alter myself.... were it not this way, I couldn't then take full credit when it blows up

I also remember a few interesting miles on the way down to Cat, when I got left behind at the petrol station on the outskirts of Paris and the intercom radio signal was fading fast.... I hadn't asked what route everyone was taking, so there was only one thing for it... speedo off the end of the scale, rev counter pretty close to the redline... and this was before Water Injection (you may recall getting soaked in the car park as the system was primed )

Cheers,

Pat.

Steve Lawson

Just to throw something into the equation I was looking at a B4 and a V5 at Scoobysport today and there was something odd on both cars.
Both vehicles have lost big ends not sure which ones as the damage is is certainly
extensive on one of the cars.When I actually looked at the gearboxes on both cars there was a large patch of oil on the O/S of the box.
Now what this brings me to is this oil has got to have come from somewhere and the only thing behind the flywheel is the oil separator plate(part of the engine breather system).I have seen these leak but usually it just trickles out the bottom of the gearbox this looks like its been blown out and almost splattered the box,also bearing in mind that it has to come round the flywheel and clutch assy.
Basically this plate is held on with 5 or 6 screws and all that seals it is silicone sealant(1215 three bond) and there should not be a great deal of pressure build unless you are getting blowby from the rings(unlikely) given the average age/mileage of the cars failing.
Now the $64,000 question is it due to high boost/high rpm?
Can anyone else also say they have seen this strange oil patch,I honestly can't as these are probably the first cars I have seen outside the dealer network having failed this way(7 years at a Subaru dealer and never seen a big end failure!)
Tomorrow time permitting I will try and inspect the breather system some more and let you know the outcome.

Steve

[This message has been edited by Steve Lawson (edited 17 July 2001).]

firefox

Hi Steve,

The early cars used plastic covers with metal inserts around the screw holes.

I have seen one leak, but this is not on a big end engine failure engine.

I have seen these covers crack. Subaru now offer metal alternatives.

The crank breather does produce more pressure than the heads. If you check the little plastic "T" piece that splits between the inlet pipe connection and the PCV, you will see an unbalanced split.

In theory, the inlet pipe at high revs (cruising) or under boost will see a vacuum, as air is being sucked in by either vacuum in the manifold (PCV) or vacuum in the inlet due to the turbo sucking.

This should remove the oil, but its a balance between the oil breather pressure and the vaccuum present.

Keep us informed.

J.

MorayMackenzie

ChristianR,

Skylines do not go up to 12,000 RPM as standard. IIRC, they have a standard rev limit that's not far of the STI's 8250RPM region... I suspect it was less than 9000RPM anyway.

Moray

johnfelstead

Great thread this, Ive been a bit busy of late with my own problems with the plastic pig and Esprit so just been lurking. Pat, welcome to the novel writers guild.

“I remember when some leading tuners said you absolutely had to change the fuel pump on an escort cossie before anything else as the standard one was at its absolute limit. That seems to have changed now, why? Im sure its mainly down to better knowledge.”

Not true, you still need to uprate the fuel pump on the Escort Cosworth if going above 270BHP. It doesn’t flow enough as standard, period. One thing I always do when building a race car or uprating a road engine is do a flow test on the fuel system, measuring the flow after the presure regulator. That is in the return to the tank/swirl pot. What matters with regards to setting the duty cycle up on the injectors is that the rail presure is set correctly, what really matters when you are talking about high RPM/Load performance though is flow rate. Now what I have been hearing of late is that Impreza Fuel pumps are starting to fail. Bob, do you as a matter of course do flow tests on the fuel return? Have you noticed any week figures on the older cars or track cars? One thing that kills these modern fuel pumps is when they are allowed to cavitate due to seeing air for short periods of time. People who corner hard on less than 1/3 of a tank full are risking this happening.

“I also dont see the need to just jump in and drive off (wait 30 secs or so to let the oil get round the engine)“

If it took that long to get oil presure you would have a big pile of junk in your engine bay. It takes a split second to get oil presure. You are best just driving off gently, cat equiped engines don’t like sitting idling when cold.

“Do you think oil coolers will cool the oil too much? I was thinking of having one fitted, perhaps I should wait a bit until a bit of R&D has been done with oil coolers and the Impreza. Funny the last thread that PE wrote about was oil cooler they were suggesting an oil cooler could be beneficial. Sorry to say PE just got slagged and accused of ripping off the list by trying to sale their products here. I would have thought an oil cooler would only be a good thing to have, especially for those who go on the track.”

The oil/water cooler fitted as standard to the Impreza Turbo is very efficient at its job. If you do install an oil/air cooler ensure you use a thermostat installed sandwhich plate so the cooler is bypassed untill the oil is up to temp. It will take longer to get good oil temp too as the oil/water cooler serves 2 functions. It is designed to warm the oil quickly and then keep it cool. WRC cars use oil/water coolers. The limiting factor to this is actually the eficiency of your water cooling system.

“Barattero recommended the WRX rally driver to not get pass 7200 rpm.”

This is because above 7200rpm the turbo will go supersonic on a 34mm restricted turbo, it isnt oil/bearing related.

“I dont know what procedure is recommended for mechanics when they change your engine oil, but I have witnessed the procedure of fitting the filter dry/rather than filling with oil first by one of my local Subaru garages.They then start the engine until oil pressure is acheived, which can take as long as 5 seconds.”

You should always pre-fill the oil filter. What I have always done is remove the spark plugs so the bearings arent seeing any compresion loadings whilst you crank the engine to prime the oil system. It is also far less demanding on the battery and spins slightly faster speeding up the priming process.

“Maybe this isn't seen normally but holding the revs. high leads to the point where the fuel system pressure drops and drops to the point where it cannot sustain the fuelling necessary over time at (almost) max. revs in top.”

This is why you need to know what the fuel flow rate is. The way a fuel injection fuel system operates is very simple. The pump runs at a set flow rate, it never changes. The presure seen does change as that is controlled by the regulator and varies depending on boost/vacumn in the inlet manifold. I would be amazed if the standard fuel pump can flow sufficient to keep the injectors fed on high boost/load (higher presure fuel rail) high revs. What is the flow rate on the Impreza pump? Have you got figures on that bob?

“One of my concerns about going FMIC is the effect it will have on water temp's, and the knock on effect, to oil temps. I think at the very least, an oil cooler should be used in conjunction with a FMIC, and depending on core design, maybe even an uprated rad'.

Very good point. The oil/water cooler relies on the water system to provide enough capacity to control the oil temp. What you should do when fitting a FMIC (I havent seen this done) is seal the gap between the intercooler and radiator. This ensures the airflow is most eficient through both matrixes. If you don’t do this then the airflow through both is compromised. The air tries to spill out the sides of the gap and both matrixes run less eficiently.
The Impreza is a good design when it comes to radiator surface area, there is plenty in reserve and the water temp is controlled eficiently by the thermostat. Going FMIC could compromise this. It needs some analysis I think.

“As Robski says it is well worth noting that race oils are not designed for road use, as mentioned above they are specifically designed to be changed after a low number of miles. So while it may seem as though you have a better oil .... most oil manufacturers do a race oil, best to avoid. “

There is race oil and race oil. In the good ole days of Castrol R30 and R40 (what a wonderful smell ) then you would be mad to use that in a road car. Most oils now used are ideal for fast road use. Oils like Motul 300V Competition and RS 10-60 are superb for prolonged use.

“I'm running Motul Competition 300 (something) 15-50 fully synth.”

This is the oil we have used in our Escort Cosworth GroupA high compresion engine running very agresive ALS. This was recommended to us by DOME, our engine is a Mountune spec GroupA unit. It is used in many WRC engines.

An idea you can use to monitor your temps on the oil and water systems (and charge temp too) that is dirt cheap and involves no mods for sender units and gauges is to do what I do on the race engines as a back up. Buy yourself some temperature strips in the 70-130 degree range. These are adhesive strips that change colour at set temperatures and are perminant markers of the max temp seen. You can stick these on the oil filter, radiator top and bottom inlets/outlets. You can buy lower temp ones for monitoring your charge temps too. Its not as acurate as a thermocouple in the airflow but you will get a damn close indication.

These strips cost just over £1 each. I had them all over my cooling, oil and charge system this weekend as I had installed a new F1 cored rad and wanted to see what this had done for me. It’s very usefull especially if you are driving hard on track as you don’t have time to look at the gauges during high load usage. You get a perminant max registered, they are very acurate.

Sadly, I had a very bad experience with trying a diferent oil 3 weeks ago. I have been running a 5 litre prototype V8 engine in the back of my friends Esprit race car since 1997 without any issues. We rebuilt this every 12 months and never saw any wear. This is a fully dry sumped, genuine 400BHP normally aspirated jobbie. Steel crank (1 of 3 ever made) Steel rods etc. etc. it was reved to 7500rpm, the inlet valves are 2” diameter, we are talking big loads here. After talking with some oil specialists we were convinced to try a new oil designed specifically for race V8 engines. Well, 8 laps round croft was enough to see one conrod through the dry sump pan, another went through the camshaft, splitting it into 4 pieces and then exiting out the valley gasket. The failure was caused by big ends picking up, overheating to the point the rods were blue before they let go. Theres £15K and 1 years worth of hard work down the ****ter. I wont mention the oil suplier as it may not have been this, just coincidence, I don’t have any analysis of the oil yet so it would be unfair. I think I will stick with what I KNOW works from now on though…….

Keep the info coming, this is good stuff.

CraigH

John,

Referring to your comment about the turbo restrictor and 7200rpm statement, do you honestly believe production Scoob engines are built/engineered well enough for this type of speed or more, as in STIs?

8k on an STI is a serious limit for a road engine, especially as the only real differences to a UK car are the heads. Would anyone want their UK car revving to 8k?

I appreciate the comments made about rev limiters being exceptionally (or can be) bad for the engine, but surely it's still better than hitting ultra high revs?

The only 2 cars I can think of that have a higher rev limit than a std STI are an S2000 and a 355/360.

No other turbo cars are even close are they?

ChristianR

iTrader: (1)

Skyline goes up to 12000rpm or something!! screams like a bike!! vrooooom vrooooom!

Pieman

Now totally confused!
For idiots like myself, put simply, what viscosity oil is best to use then? 5W-40? Synthetic or semi-synthetic?

John Brinkman

Hi

I have been reading this thread with extreme interest, I have had 4 big end no.3 bearing failures.

My first Subaru was a MY98 GT purchased new covered +- 40 000km and it had a big end no3 fail. Modifications at the time were an MRT exhaust and cone air filter, nothing else done. It was rebuilt and failed again +- 1500kms later. I had just finished a run on the highway at about 180km/hr for +-10 minutes. I then purchased and STI IV type-R, big end failed whilst on a long trip on the open rd, was doing about 180km at the time. I had the engine rebuilt and it failed again around 1500kms later

I now own an MY01 with no modification (and none planned) whether these failures were caused by mods of not is anybodies guess but I am not taking any chances. I also drive a bit slower now

One of my theories at the time was that the pressure release on the oil pressure pump was sticking open resulting in low oil pressure at high rpm. Not enough to light up the oil pressure light but enough to cuase bearing failure. (it was only a theory )

JohnB

Pieman

Come on lads - what viscosity oil should we use?

dfullerton

Just a thought Subaru must know about this, so cant we find out what they think. Cannot think for a mo that with all their R&D they do not know about this

johnfelstead

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:<HR>John,
Referring to your comment about the turbo restrictor and 7200rpm statement, do you honestly believe production Scoob engines are built/engineered well enough for this type of speed or more, as in STIs?
8k on an STI is a serious limit for a road engine, especially as the only real differences to a UK car are the heads. Would anyone want their UK car revving to 8k?<HR></BLOCKQUOTE>
what you going on about Craig? That statement of mine is explaining why a turbocharged rally engine that is fitted with an FIA 34mm restrictor is mapped and designed to not rev high. Above 7200rpm the air passing through the restrictor goes supersonic so cant be compressed. Above 6200 a low compression GroupA engine loses a large amount of its torque. The norm these days is to run high compression turbo engines in WRC apps to limit the effect of the restrictor strangling the turbo compressor.
As to your comment on max revs. You cant make a sweeping statement like that. All engines are different and you will find that as time goes on more cars will be fitted standard with lower capacity, higher revving power plants as these are more efficient. The limit on most production engines is actually the valve train components and not the bottom end. Most road engines are installed with puny valve springs that allow valve bounce or flutter at the higher limits. The rev limits have been rising higher in modern engines mainly because the valves are much smaller on 16V engines than 8 valve so have less mass to control.
<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:<HR>I appreciate the comments made about rev limiters being exceptionally (or can be) bad for the engine, but surely it's still better than hitting ultra high revs?<HR></BLOCKQUOTE>
I didn’t say a word about limiters. If you are referring to pats post then he is spot on. You should avoid using the limiter as much as possible. It should be used as a saviour, not a shift point indicator.
<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:<HR>The only 2 cars I can think of that have a higher rev limit than a std STI are an S2000 and a 355/360.
No other turbo cars are even close are they? <HR></BLOCKQUOTE>
The Honda typeR’s rev pretty high. My first rally engine, an Imp 998 hartwell unit reved to over 11,000 rpm safely. The V8 race engine we just blew sat happily at 8000rpm, we limited it ourselves to 7200rpm to help it last longer. The second engine of this design was used in FIA GT 4 hour races without problems, that used an EFI individually trimmed per cylinder ECU. A lot about making an engine last is simple stuff like keeping the oil and water temps in the right ball park plus ensuring the fueling is spot on.
You also need to understand that using the upper rev limit has a different effect depending on what gear you are in. Turbo engines in particular are affected by this because the way a turbo works ensures that the higher the loading (i.e. drag) the more the turbo tries to flow air. It’s a system that responds to load and not revs as such. The heat generated in a turbo engine increases massively as the loads increase with higher gear selection. If you want to try a real nasty experiment just sit on the motorway at 70MPH, hold the speed with your left foot on the brake and give it full throttle. Prepair for a blown head gasket real soon! What this is simulating is the sort of load the engine sees at high speeds due to aerodynamic drag (drag goes up as a square of speed, an extra 10MPH is a big diference in drag and therefore load). Now add on top of that the fact the engine revs will be higher and you have a recipe for failure.
As an aside, my cosworth engine in the Westie has a lower compression ratio than standard. As standard it was 8:1, I have dropped this to 7.6:1 because I wanted to protect myself from det if I had a bad batch of fuel. I can quite happily run this car on 95ron and 1.6 BAR boost without any concern. I always run on 97ron but I don’t panic if I cant find any. This has a rev cut point of 7200rpm yet the internals of a cossie are capable of much more being all steel etc etc. I wonder why Ahmed put the limit at that point? If you ever get the chance to talk with Ahmed Bayjoo, listen to him. He puts a big emphasis on fuel flow to the injectors. The first thing he insists on with his conversions is a fuel flow check being carried out.

steve McCulloch

oil

10w50w is about right (Silkolene). (But - Dont use crap like Castrol Magnatec - it breaks up almost immediately!)
IMHO 5W40W is way too thin.

My turbo warranty is totally invalidated running at 5w40w.

Back to the thread

Bob Rawle

John, by race oil I do mean that not the "competition" oils such as those you mention and which I have also suggested should be used on other threads, Motul 300V 15:50 is what is going into my car next as a point of info.

The smell of "R", what a pity that is not around much any more !!

What do Subaru recommend ... for the Euro spec car the official workshop manual states that for normal use 5w-40 should be used and for "heavy duty" use then 15w50 (60) should be used and that oil should be changed more frequently than the recommended service intervals, once I've moved house I will find the page and scan it in for any that are interested enough although any Subaru dealer should be able to confirm that.

SecretAgentMan

Well, just serviced the car, got some Motul 300V again, the car seems to run well with that oil.

I managed to sort the oil temp sensor at the same time (prepped sump bung), and I was gobsmacked on how long it takes for the oil to get up to working temp.

It's at least 3 times more than it takes for the water temp to reach normal.

/J

steve McCulloch

Bob - can you get me some while your at it!

I'm currently very bored over here in the States

Back to the thread

JohnS

iTrader: (1)

Just bringing this thread back to the top, as it has been a month since anyone posted to it, and there is some excellent information in here.

scoobyboy

just to throw a spanner in the works iv got a standard turbo in bits 85,000 mls on the clock and no1 big end has just gone so can it still be heat sink?

WREXY

Towards the top of the page on my post, I said that Subaru had their own labelled oil here in Greece. I said that it was fully synthetic and it was 10W/40. I found out that the oil is semi synthetic 10W/40

WREXY.

JIM THEO

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:<HR>Originally posted by WREXY:
<B>Towards the top of the page on my post, I said that Subaru had their own labelled oil here in Greece. I said that it was fully synthetic and it was 10W/40. I found out that the oil is semi synthetic 10W/40

WREXY.[/quote]

Hi WREXY
These oils are special order from the Greek Subaru department and are Cyclon (or Chevron I can't remember exactly this time). You can also compare the plastic bottle from the Subaru oils, with the same bottle from the original brand (Cyclon or Chevron), it's the same.
With that said, I don't like the idea of semi synthetic 10-40 oil in a turbo engine like Impreza, with 40 c. degrees!
Jim

WREXY

I totally agree with you Jim.

Wrexy.