Another EJ257 gasket thread
09 February 2005, 04:54 PM
#35
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would be nice to know the head temperatures too, not only the EGTs, and although u still used water and methanol injection, sustaining EGTs > 1000°C is not healthy for an "everyday use" engine.
Carlos H.
Carlos H.
09 February 2005, 05:12 PM
#36
Originally Posted by R19KET
Think it's a Sunbeam?
wish it was a an A110 though, it would be worth a hell of a lot more!
Last edited by Tim W; 09 February 2005 at 05:43 PM.
09 February 2005, 05:22 PM
#37
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Interesting post .....
Originally Posted by AZScoobie
Classic... This is a classic situation..
If you run more advance you will have cooler EGT. why? Because you are starting the burn earlier and leaving less unburnt fuel to exit the CC and burn..
But you cant run more timing because you dont have the octane to support more advance.. Strike one..
You find that if you run a richer AFR the EGT is about the same.. Thats common. Its so rich now that more fuel is not helping to cool EGT. Its helping to raise it now. I think if you did a longer pull you might see more temp but you have already reached that "area" where a rich pump fuel mix reaches. I really do believe in that temp range "area" thing.. I have seen it many times. You will have to do something wacky to get EGT ALOT higher then it already is.
What to do? Reduce compression
That means reducing the boost and running more advance. Oh boy.. Dont want to do that now do we? less trq.. Maybe less power.. Hard to say but less trq for sure. We need that pressure to force air through the Engine.. If we dont force it in we cant make power can we? If we have a small compressor and all that pressure is heating the intake charge up 100 degrees we have higher EGT... hot in- hot out. If we have a big cool running compressor then reducing that boost simply forces less air in and we dont get that cooling effect the smaller compressor had by reducing boost.. We do make less power because less airflow through the engine means less power. Wait.. Less power means less heat... 
Why are your EGT's hot? Cause you have a super high compression motor (on boost) that needs ALOT more octane then you have available for knock buffer so you have been forced to tune the car so its super ineffecient.. IE tuned around boost We all do it. But your result is alot of wasted fuel, HOT EGT and I have a feeling you are dependant on that WI... But your actual result is alot of P-out on pump fuel and alot of Heat because thats a by product of the power you just made.
You can reduce the boost, Advance the timing say 4-5 degrees(10 degrees temp drop for every 1 degree advanced) and probably remove some more fuel.. But then again when you reduce that boost and add that timing in you might find that the fuel cools EGT off Wait.. thats how the factory tune is setup.. imagine that
I wrote that out so people could see trends and effects.. But your EGT is not bad at all in my honest opinion... Adam.. I would be curious to what it is with the WI off... I always found peak power on STI EJ motors around 800-850C on the Dyno. I think you are risking nothing running those temps but hey.. thats me.. I am loony.. I run 1000C on the bottle Just make damn sure your cooling system and oil system can remove that engine heat if you expect a high duty cycle or you will heat soak on the track, det and could blow the engine.. Keep the block cool.. Keep the EGT hot.. make power.
Cya
Clark
If you run more advance you will have cooler EGT. why? Because you are starting the burn earlier and leaving less unburnt fuel to exit the CC and burn..
But you cant run more timing because you dont have the octane to support more advance.. Strike one..
You find that if you run a richer AFR the EGT is about the same.. Thats common. Its so rich now that more fuel is not helping to cool EGT. Its helping to raise it now. I think if you did a longer pull you might see more temp but you have already reached that "area" where a rich pump fuel mix reaches. I really do believe in that temp range "area" thing.. I have seen it many times. You will have to do something wacky to get EGT ALOT higher then it already is.
What to do? Reduce compression
That means reducing the boost and running more advance. Oh boy.. Dont want to do that now do we? less trq.. Maybe less power.. Hard to say but less trq for sure. We need that pressure to force air through the Engine.. If we dont force it in we cant make power can we? If we have a small compressor and all that pressure is heating the intake charge up 100 degrees we have higher EGT... hot in- hot out. If we have a big cool running compressor then reducing that boost simply forces less air in and we dont get that cooling effect the smaller compressor had by reducing boost.. We do make less power because less airflow through the engine means less power. Wait.. Less power means less heat... Why are your EGT's hot? Cause you have a super high compression motor (on boost) that needs ALOT more octane then you have available for knock buffer so you have been forced to tune the car so its super ineffecient.. IE tuned around boost
We all do it. But your result is alot of wasted fuel, HOT EGT and I have a feeling you are dependant on that WI... But your actual result is alot of P-out on pump fuel and alot of Heat because thats a by product of the power you just made. You can reduce the boost, Advance the timing say 4-5 degrees(10 degrees temp drop for every 1 degree advanced) and probably remove some more fuel.. But then again when you reduce that boost and add that timing in you might find that the fuel cools EGT off
Wait.. thats how the factory tune is setup.. imagine that I wrote that out so people could see trends and effects.. But your EGT is not bad at all in my honest opinion... Adam.. I would be curious to what it is with the WI off... I always found peak power on STI EJ motors around 800-850C on the Dyno. I think you are risking nothing running those temps but hey.. thats me.. I am loony.. I run 1000C on the bottle
Just make damn sure your cooling system and oil system can remove that engine heat if you expect a high duty cycle or you will heat soak on the track, det and could blow the engine.. Keep the block cool.. Keep the EGT hot.. make power.Cya
Clark
09 February 2005, 05:26 PM
#38
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Carlos, remember the pictures of the pistons, running mega rich?.
>1000 only really ever been at Elvington or on one or 2 stupid stints on the road.
>1000 only really ever been at Elvington or on one or 2 stupid stints on the road.
09 February 2005, 05:45 PM
#39
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Steve yes I do remember they were mega rich, but from my limited experience with EJ257's with STi ver 5&6 heads and around 8.8:1 CR (using the stock US STi headgaskets) on rally cars using VF34 turbos with P20 exhaust housings AND race gas the max EGTs we have seen on a very very long tarmac stage (400 kms. of a Dakar type rally we have over here in Peru) were 900°C. Although we had headgasket failure it was only once in a whole rally season. Last year we change the headgaskets at mid season and had no headgasket issues. BTW this was with 1.6 bar peak boost tappering to 1 bar of boost @ 7k rpm and very advanced timing (33º) with 0.8 lambda.
Now we are using on a another EJ257 STi ver 5 rally car the phase 2 EJ25 1.4mm headgaskets, will see how long they last.
One of the biggest differences I have seen between US EJ257 tuning and UK EJ257 tuning is that most tuners and users in the US have access to race gas while on the UK people rely on Optimax plus NF or Methanol.
Carlos H.
Now we are using on a another EJ257 STi ver 5 rally car the phase 2 EJ25 1.4mm headgaskets, will see how long they last.
One of the biggest differences I have seen between US EJ257 tuning and UK EJ257 tuning is that most tuners and users in the US have access to race gas while on the UK people rely on Optimax plus NF or Methanol.
Carlos H.
Last edited by carlos_hiraoka; 09 February 2005 at 08:00 PM.
09 February 2005, 07:06 PM
#40
Hmm I see a plan here ..my next car will Run on 85%ethanol and 15%gas.
Cheper than gas also, and for sale @ most town's in Sweden
Max EGT I seen so far was 900 btw, before leaning it out and razing the adv.
Jan
Cheper than gas also, and for sale @ most town's in Sweden
Max EGT I seen so far was 900 btw, before leaning it out and razing the adv.
Jan
10 February 2005, 07:47 PM
#41
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Having a little play tonight, I found that the wastegate solenoid duty cycle to hold 1.4 bar to 7300 RPM was at least 10% higher than it was in the midrange. When running this higher duty cycle I felt the engine sounded strained and not breathing freely. Additionally, there was a lot of knocklink activity in areas where it is already well pulled back. This all suggests to me again that the P450 is really struggling to flow the air up there. Head gaskets still intact for now. I think I might just keep a flat duty cycle on the 0.6 bar actuator so that the EGBP doesn't go too high. Roll on the GT30R and proper easy airflow I hope.
11 February 2005, 03:55 PM
#43
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Originally Posted by john banks
Having a little play tonight, I found that the wastegate solenoid duty cycle to hold 1.4 bar to 7300 RPM was at least 10% higher than it was in the midrange. When running this higher duty cycle I felt the engine sounded strained and not breathing freely. Additionally, there was a lot of knocklink activity in areas where it is already well pulled back. This all suggests to me again that the P450 is really struggling to flow the air up there. Head gaskets still intact for now. I think I might just keep a flat duty cycle on the 0.6 bar actuator so that the EGBP doesn't go too high. Roll on the GT30R and proper easy airflow I hope.
11 February 2005, 04:22 PM
#44
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EGT probe broke at the last swap. Present air temp probe is at the airfilter. With planned ECU change I want a charge temperature compensated map whether MAF or speed density.
Need a new one, trying to decide whether to get SPA dual to match the rest or a Greddy Analog one at 1/3 of the price
Anyone know how much higher the boiling point of coolant/water mix would be with 1.3 vs 1.1 bar cap? Quirt suggested 2.0 bar if I had the coolant system to handle the pressure... could change hoses, but what else?
Need a new one, trying to decide whether to get SPA dual to match the rest or a Greddy Analog one at 1/3 of the price
Anyone know how much higher the boiling point of coolant/water mix would be with 1.3 vs 1.1 bar cap? Quirt suggested 2.0 bar if I had the coolant system to handle the pressure... could change hoses, but what else?
Last edited by john banks; 11 February 2005 at 04:25 PM.
11 February 2005, 09:02 PM
#45
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Pressure - Water - 50/50 antifreeze
1.1bar-----122C----130C
1.3bar-----125C----133C
2.0bar-----134C----144C
I'd be wary of the heater matrix at 2.0 bar
You can also buy a coolant such as Evans NPG that has a much higher boiling point (188C) and a lower operating pressure. As used in most serious forms of motorsport
http://www.evanscooling.com/html/auto1.htm
Andy
1.1bar-----122C----130C
1.3bar-----125C----133C
2.0bar-----134C----144C
I'd be wary of the heater matrix at 2.0 bar
You can also buy a coolant such as Evans NPG that has a much higher boiling point (188C) and a lower operating pressure. As used in most serious forms of motorsport
http://www.evanscooling.com/html/auto1.htm
Andy
11 February 2005, 09:47 PM
#46
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Not really much difference between the boiling points is there!
NPG looks interesting, I was thinking of the Subaru Coolant Conditioner, weakest coolant mix to prevent freezing and water wetter as a cocktail to try. What do you suggest Andy?
NPG looks interesting, I was thinking of the Subaru Coolant Conditioner, weakest coolant mix to prevent freezing and water wetter as a cocktail to try. What do you suggest Andy?
11 February 2005, 10:05 PM
#48
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http://forums.nasioc.com/forums/show...ight=evans+npg
Sounds like fun draining the old coolant, also lower specific heat cap than water or 50/50, but that probably doesn't matter too much?
Thanks for the hint Paul.
Sounds like fun draining the old coolant, also lower specific heat cap than water or 50/50, but that probably doesn't matter too much?
Thanks for the hint Paul.
12 February 2005, 11:46 AM
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don't see the point of running beyond 7500rpm, I find myself grabbing for gears sooner than that. I have fully uprated internals and I am still cautious of running anywhere over 7500 at full throttle though datalogs have shown it to hit over 8k on occasions.
7.5 really is enough.
Still waiting for the gt30r to go in myself, be interesting to see your results.
How do you hope to get 520bhp from a turbo which flows 500bhp at its limit? octane boosting somehow?
7.5 really is enough.
Still waiting for the gt30r to go in myself, be interesting to see your results.
How do you hope to get 520bhp from a turbo which flows 500bhp at its limit? octane boosting somehow?
12 February 2005, 12:57 PM
#50
Adam, you have the advantage of a widely spaced set of 5 speed ratios that you chose pretty much to match the expected power and torque delivery of your engine. Those of us with 6 speed boxes have a more compromised close set of ratios which mean we're going to have to swap cogs more often...however, if we can use more revs then we can hold on to gear just that bit longer...granted this is more than likely going to be pointless on the road, but on track or up the drag strip it would make a big difference
12 February 2005, 01:05 PM
#51
Originally Posted by Adam M
I am still cautious of running anywhere over 7500 at full throttle though datalogs have shown it to hit over 8k on occasions.
Originally Posted by Adam M
7.5 really is enough.
Originally Posted by Adam M
How do you hope to get 520bhp from a turbo which flows 500bhp at its limit? octane boosting somehow?
12 February 2005, 03:24 PM
#52
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Don't recall mentioning 520, but I have no trouble changing gear at whatever RPM you tell me to, unless it is slipping silly. 500 is also optimistic on Optimax with a safe map as well I think, but it should be a little way ahead of where I am now. AndyF's power plots notably peaked quite high up at least on the 2.33 running more boost than I intend to. Setups I've had so far are falling dead on the 2.5 at 5000 RPM if you run enough boost.
12 February 2005, 05:55 PM
#53
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john, you and I both know that the rev counter is hardly indactive of the true rpm the engine is running, and its reponse is far from real time.
Since I judge change up from the the rev counter and the rpm logs come from the crank position sensor, I think it is hardly fair to criticise my throttle control! :P
that said, am happy to admit I am not too skilled where car control is concerned which is why I keep the car performing within both mine and its capabilities, not its.
Since I judge change up from the the rev counter and the rpm logs come from the crank position sensor, I think it is hardly fair to criticise my throttle control! :P
that said, am happy to admit I am not too skilled where car control is concerned which is why I keep the car performing within both mine and its capabilities, not its.
12 February 2005, 06:33 PM
#54
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I'm no driving god, and I occasionally lightly brush the limiter if it is too close to my change point, but from the rate of the rev counter's movement it isn't too tricky at least once you are out of 1st or 2nd gear to time your change properly unless you're spinning the wheels all the way through the gear? The RPM signal to the tacho seems quick, the needle is a little damped, but if you ask me to change at 7500 RPM every time I don't think I'll be more than 200 RPM out? Never really been a problem to me I don't think, maybe I could set the rev limiter at 7900-8100 and aim to change at 7500 RPM depending on what the power plots look like?
12 February 2005, 08:27 PM
#56
Hook, line and sinker. 
The rev counter under-reads by 250rpm when you are in the 8000rpm range on an impreza, so you must be a bit of an animal to be using the rev counter for gear change judgement and still overshoot it by an indicated 750rpm. Poor engine.
Bit of advice Adam, dont use the rev counter to judge gear changes in first, you should be able to do that change blindfold on feel alone. You have no excuse for over reving in any other gear, even with wheelspin and 500BHP.
The rev counter under-reads by 250rpm when you are in the 8000rpm range on an impreza, so you must be a bit of an animal to be using the rev counter for gear change judgement and still overshoot it by an indicated 750rpm. Poor engine.
Bit of advice Adam, dont use the rev counter to judge gear changes in first, you should be able to do that change blindfold on feel alone. You have no excuse for over reving in any other gear, even with wheelspin and 500BHP.
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