TRIGGER

I could be way off the mark here, but what octane level fuel do you use ? I was put off a ver5 as with crappy uk petrol (95-97 ron) it would run too hot and engines have been known to blow.

Seraph

Guys

I own a Ver 5 STI and had a blown engine 3 months back due to overheating resulting in a broken conrod. I live in Singapore (ave 25-35 DecC throughout the year).

My car was fully rebuilt including engine block and now, I am do everything I can to prevent the same from happening. I.e. Alum oil sump, oil cooler.

One thing that scares me is the oil temp readings are still high. I am trying to determine whether it's a inaccurate sensor or my engine is running too hot. My figures are below (after engine fully warmed-up). Hope you guys can share your thoughts whether they are normal.

Type of car (Year/Ver/STI?) - Ver 5 STI Type R Black

Idle (after 10 mins) - 90 DegC

Day City Driving 95-105
Day Heavy Traffic (Start/Stop) 100-110
Day Crusing Expressway (Between 70-100 km/h) 98-105

Night City Driving 90-100
Night Heavy Traffic (Start/Stop) 95-110
Night Crusing Expressway 90-100

Track driving 100-125


THANKS!!!

jwhitton

Might also be advisable to monitor the oil pressure. Can you do these and if so what are they?

jon

Seraph

Jon

Yes, I have also been monitoring my oil pressure. BTW, my meters are from Lamco (standard Subaru options).

Cold start - 5-6kg

After warm up.....

Idle - 3kg (2kg before installing oil cooler)
light trottle - 5-6kg
mid-full trottle - 6-6.5kg

Hope this provides more stats. Also, my water temp sensor (standard one next to fuel guage) always maintains slightly below half point. It gets there pretty quickly even after cold start but doesn't change after it reaches this point.

Another fact, I have a enlarged aluminium oil sump with baffle plates (6.5 ltrs including oil cooler). The oil temp sensor is now about 2 inches from the headers (thermal wrapped). Hope this doesn't skew the readings too much.

Thanks!

TRIGGER

Thats the whole point - I dont know what petrol they have in Singapore, and therefore what he is using !

Seraph

OK Guys.....

We get 98 Octane petrol in Singapore. I have also installed a Broquet fuel catalyst (dealer claims this is also used by Prodrive in UK).

So, what is the diagnosis? Is the temp normal or should I be checking my oil temp sensor?

Thanks for your help.

TRIGGER

Subaru fitted the Version V's with different settings than the version 4 and so anybody over here runs them with octane booster additive to prevent these problems. Version 4's dont suffer and seem to be able to run on anything, but just have reduced boost. (There are many threads regarding the reason for the additional temp with lower octane petrol). They are designed for Japanese 100 octane. Problems should only really occur though if pushing the car really hard - in Singapore that seems unlikely !

Seraph

Trigger

I don't think my ECU is complaining about the octane levels. I have been consistently getting between 1-1.2 bar boost.

Anyone knows what the optimum operational temps for the Ver V STIs are?

Also, any recommendations on a early open water termostat? I currently have a 71 DegC fitted. Stock is 78 DegC. I know of products that open as early as 65 DegC. I did not go for that as the vendor said that will not allow the WRX to attain it's optimum operation temps effectivily. Hence my earlier question.

Bob, Peter, DYNT and other Scooby gurus.... Please share your experiences on this issue.

Thanks

Trout

iTrader: (1)

Seraph,

the lowering of octane level on an STi V will not lead to boost being reduced - that is the nub of the fuel related issues with V cars. The boost levels are maintained and so the engine knock - with the pistons overheating. The JECS ECU relies on retarding ignition if Knock is detected due to low RON rating or lean running. In this scenario, if the RON level falls too much, the required ignition values are outside the standard map parameters, therefore knock, therefore overheating pistons and a dead engine.

BUT this will happen very quickly it is a critical rather than chronic effect.

Also, AFAIK, Version IV cars are not immune to this problem.

Do you have water temps - my V runs between 88 and 94 - don't have oil temp guage fitted yet.

To make you feel more comfortable, 98 RON with Broquet (Prodrive do fit them to P1 and 22b cars in the UK) should be fairly safe UNLESS you have made the car breathe more easily (induction kit/exhaust). If that is true you may experience leaner running.

Cheers,

R

[This message has been edited by Rannoch (edited 12 October 2000).]

R19KET

It's strange how oil temps seem to vary so dramatically, car to car. My car reads about 40~45 deg'C on cruise, and rarely goes above 70deg', even on the track. No oil cooler.

I suspect that the various sensors read +/- 10/15 deg's, and we should both try an altarnative, to compare.

If you have an under tray/splash guard fitted, remove it. They greatly reduce air flow to the sump.

I think the other thing worth mentioning, is oil quality. Some well known, high profile brands, are really very poor. Make sure the oil you use, is based on polyol ester. Good quality oil retains it's film strength, at very high temps, and won't break down.

You say your engine failure was due to overheating, was it the big end, or small end that picked up......or was it due to det'.

Mark.

Seraph

Rannoch

I do not have a water temp meter and rely on the factory one beside the fuel guage. There are no temp markings apart from H & C. At all times, the water guage is slight below the half mark. Anyone knows what this would map to in terms of actual degrees?

Mark

My engine overheating was purely internal. There was no water spills or radiator sludge. Basically, I was cruising between 200-230km/h for about 20 mins. Suddenly I heard a loud bang and my car lost compression and ran on 3 cylinders.

When I popped the bonnet, there were no signs of any problem but my oil temp registered 135 DegC, which was extremely high. On investigation at the workshop, my conrod for Piston 4 was bent and the Big end bearing broke into 3 pieces!

Since then, I’ve fully rebuilt the engine including block and have installed a larger aluminium oil sump, oil cooler, low temp water thermostat (71 DegC).

I have also got a cold air box and equal length headers (thermal wrapped). I next plan to bolt on the BPM full Twister system when it eventually shows up.

The only thing that concerns me is the high oil temp readings and thus I have not been pushing my car hard, pending confirmation that everything is normal. In fact, I will only upgrade my exhaust when I am convinced that my car is running normally!

I have a A/F meter and the mixture seems OK. When I accerate, it goes very rich, between 10-8. At idle, I am near Lambda at 14.5. The strange thing is sometimes my meter totally leans out, especially on gear change and trottle off. Is this normal?

Yes, I am running with undertray on. If I remove it, what is the likely difference in temps? Thanks Bob for your advise. However, I have concerns for my weak aluminium sump and perhaps need to order a metal harness (suggestions?) before throwing away the tray.

So guys, please advise me if the oil temps I have described beginning of this thread is acceptable and within operating range. Also, what is the operating range of the Ver 5 STIs?


Thanks guys
Douglas


[This message has been edited by Seraph (edited 13 October 2000).]

Stanley

Cruising at 200 to 230km/h on a type R I wonder if the engine rpm went beyond 8000rpm. The maximum speed I know is about 240km/h from a test in Best Motoring. You have my admiration for running it almost flat out for about 20 minutes!

Seraph

My final drive is 4.44. I personally have driven my Type R to about 250 km/h. RPM about 7500.

My friend with the same car has achieved 260km/h before, albiet for only a short time and he said he virtually had to redline the car. Remember, STIs have a redline of 8250 RPM.

Anyway guys, I am still awaiting response WRT the Engine Oil Temps.

pwebb

hi,

I have an sti 5 with the lamco gauges - oil temp rarely goes over 90C - and that is when in town in hot weather only - the rest of the time it drops right back to 60 or 70 C - pressure is constant at about 2/3 of the way accross the dial - with only slight changes during acceleration on the lamco gauge.
I have just been over to france and even after sustained high speed motorway stretches the temperature of the oil went DOWN not up at high speed.

The sti engine has built-in oil coiling underneath so any reduction in air flow under the car will adversely effect the cooling - as correctly stated by Mark - adding the undertray will not help.

for the record , I use 10w-30 semi synthetic oil and change it every 3 months.

I would add that most of the blown engines I have seen have been due to sustained high speed (ab)use on low quality fuel - I try not to go near that redline for any length of time - but do have the advantage of higher gearing on my 4 door - I also use broquet catalysts and 97 ron fuel (98 in france)without octane booster unless I anticipate 'extending' the engine on occasion.

it looks likely that you are not getting enough cooling air underneath the car - it wouldn't take too long to unbolt the undertray and see if there is a difference

cheers,

Paul W

sunilp

Mr Webb, where did you source your Lamco gauges from?

Cheers

Sunil

GavinP

Douglas,

Are you still using the oil cooler in the water radiator as well as your external oil cooler ?

Looking at the "Think Automotive" catalogue I have (Mocal agent for the UK) they recommend bypassing the radiator cooler and just using the external one in hot climates.

I can't help thinking that the exhaust headers are also affecting your reading - I would move the probe as far from the headers as possible.

I hope you can get it sorted.

Thanks

Gavin

Seraph

I bought the HKS oil cooler kit for EJ20 and this bolts on at the oil filter with a front mount 15 row cooling coil.

This is in addition to the stock oil cooler.

One thing I notice is that the oil cooler doesn't really help if you are cruising below 100 km/h.

As for the exhaust headers, I've consulted a senior engineer and he tells me that air is an excellent insulator and even a 2 inch air gap is plenty.

The main mystery for me now is to determine what is the optimum operational oil temp range for the Ver 5 STI type Rs.