All the way on stock internals....

[V8Killer]

Theres actually a good Haltech mapper in this country?

[Mark Edwards]

Theres actually a good Haltech mapper in this country?

Who's that then? Can you do a good job with them then?

[^Trickster^]

Why would the oil temperatures increase with higher boost level?

The oil system is very good on the 3sgte engine, and better on the later rev 3 engine, the only problem is when used for heavy track use where the oil temperatures rise and an external oil cooler is used. Something which I would never fit personally.

People are mislead about boost pressures causing problems, its not boost pressure thats the problem it is poor tuning, a disadvantage of high boost is basically an increased intake charge temperature and the fact that your more likely to blow hoses off.

On combustion the cylinder pressures can sore 1000psi, so why would a measly 25psi intake charge have any noticable effect over 15psi?

As stated with proper tuning it will be fine, I run my td06 kit at 23psi with no problems whatsoever, I can already think of one individual, Jeff Fazio running 22psi boost than this on a stock internal engine, and making 440rwhp. Also with a stock oil system.

I have said alot of times before and stick by, that apart from improper tuning, theres a big degree of luck when getting more from any engine, some seem to last forever when people do alsort to them, then some seem to die for the most inappropriate reasons.

Graeme

[matt_mr2t]

This is what I was getting at Mark with regards to changing internals.
I'd have thought that with the right mapping you'd be fine but I guess any error would be far more devastating that at say 18 psi?

[^Trickster^]

You can detonate an engine at 5 psi with incorrect tuning, and itll make just as much damage as 30 psi.

Detonation, pre ignition etc is what kills engines, not boost pressure.

Note detonation etc is an accumlative word of which 1 or more than 1 circumstances can cause, bad mixture, bad ignition timing, too much ignition, high intake charge temperature, etc etc

You cant just run any engine at 20+psi with good tuning either, thats not what im saying, you always need supporting mods, otherwise everyone would just fit an ems and run loads of boost.

You need a good flowing engine, good cooling methods, good fuel delivery systems, good ignition systems, all of which have to increase with power output and increased airflow.

Graeme

[matt_mr2t]

Ok, so for instance on a rev2 with standalone (not yet) rev3 ecu set up with 540's, uprated intercooler and hybrid turbo of some sort (not done yet) could you run 20psi on standard internals?

As it stands I just have a CT20b, downpipe, Unichip and AVCR. It was mapped at engine advantages for 1.2 bar and they said it was fine, not running lean any where and they retarded the timing slightly to deal with the knock at very high end boost.
At the moment I have the boost quite low cause I havent got my head round setting the AVCR up lol.

[^Trickster^]

You just answered your own question really, theres no reason your cant, but if they tune it to 1.2bar and say its starting to knock/detonate then obviously there are things you need to do to run higher boost/power.

If it was easy everyone would have 1000hp engines lol

All im saying is that stock internals are good for quite alot of power with good mods and tuning, it all depends on what you want from your engine really.

Graeme

[matt_mr2t]

I'm just wondering how far I can actually go before cracking the engine open really.

My plan in the next 6 months is to replace the rev2 ecu with a rev3 set up. Not made my mind up weather to re-fit the unichip or go apexi. I have an intercooler ready to go but as it's so cold not that fussed just yet.

Then after all thats done, consider a turbo upgrade.

[Bender Unit]

Push it until it breaks and then build it up!

If the mapping is slightly off then kiss goodbye to the ring lands and be prepared to start all over again. The stock pistons can take a decent amount of punishment but the smallest amount of detonation will kill them very quickly.

I am currently working on an engine for a member. In Japan the car was reportedly making 400bhp - it was taken to a well known UK MR2 tuner to be mapped for UK fuel and as a result it dropped two ring lands. Which was the result of detonation.

I personally feel that the UK mappers are quite a bit behind the US and Japanese guys and as a result quite a few cars on stock internals have never reached what they are capable of as they get killed off by poor mapping.

Personally if I was pushing hard on stock internals I would go big turbo, low boost and lost of fuel.

[matt_mr2t]

I did think push it till it goes but then there's the risk of damaging other parts that I could have left quite happily?

[JekylandHyde]

As Trickster pointed out, boost pressure does not kill our engines, detonation does. It goes without saying that increasing boost increases the chances of detonation.

If you prevent detonation, you can get away with a lot.

Trickster quote that I made 440 rwhp @ 22 psi.
That was a GT35R turbo on a 200,000 mile original engine.
We ran as high as 27.5 psi on it.

To avoid detonation, I highly recommend:
*a good solid, safe tune
*water injection - a must on a turbo car IMO!
*race fuel (I use 110 octane leaded)
____________________________

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[matt_mr2t]

Race fuel isnt available every day for road use though?

[JekylandHyde]

True, but who needs 25 psi everday for road use?

We were extremely cautious with my car because of the incredibly high mileage and the shear amount of racing it has been put through.

The engine can be pushed very far on regular pump gas.
Exactly how far, I do not know.

[matt_mr2t]

I've always wondered why you'd need uprated internals on a car, asong as everything inside is happening as it should I can't see the danger.

Well, I'll carry on with bolt ons till I get to the point of opening it up I think.

[JekylandHyde]

At some point, you will get to the point where the cylinder pressures are so high that you might need a stronger piston.

The benefit of forged pistons is they can take lot more hits from detonation than the stockers. No matter what you do, if you are pushing an engine you are going to see some levels of detonation.

[matt_mr2t]

Whats the benefit of lowering the compression ratio as I have seen a fair few cars with this?
Is it just a thicker head gasket mod?

[^Trickster^]

Benefits of running a lower compression ratio are that you can run higher boost levels, it goes hand in hand really tho, you either have

high compression - low boost
low compression - high boost

im taking extremes here, eg, 7:1 for a high pressure turbo engine, or 11:1 for NA engines, people take compression too far, with correct tuning once again anything is possible, I dont even know my compression ratiom id guess about 8.5:1-8.8:1 but it doesnt concern me, I run a stock rev 3 gasket, 0.8mm, I like thin headgasket, less chances of failure, and (this is my assumption only) less chance of head warpage as there is less "give" between the block and the head, its tight.

Of course, higher compression ratios will yield better off boost performance, But, again it depends what you want from your car drivability wise, and what kind of setup your going for.

Lets face it 95% of us on here are for street use, so anything 8:1 to 9:1 would be fine.

Someone who has a deeper knowledge of this may jump in and land some info, my point is simply compression is irrelevant with good tuning aslong as it isnt to the extreme (compression wise)

Jeff: I run 23psi daily on pump gas (its 98 octane apparently - optimax) but if im driving hard i do put the water injection on, but the engine is tuned without it. For peoples information water injection is not for cooling, it increases the intake charge humidity which is a detonation preventative.

Graeme

[JekylandHyde]

WI does have a cooling affect.
Look up "latent heat of evaportion."
When water is forced from a liquid into a gas, it absorbs a LOT of heat.

Add WI and watch your EGTs plummet

[matt_mr2t]

Some people opinion of WI on here makes me laugh.
"What if it runs out of water"
It's a free resource, just keep it topped up lol.

[^Trickster^]

Jeff: Yes your right, I just try to stop people using it instead of upgrading there intercooler. water injection does have a cooling effect but it mainly reduces detonation because of its humidity which reduces cylinder combustion temperatures which reduces the egts

But a good intercooler/charge cooler setup will give more consistant lower intake temperatures

Graeme