Tech Questions on Boost, FPR, Injectors, Turbos etc

Right, something im struggling getting my head around and im still unsure even after comments wrote on the forum.

Bit of background info.

I am in the middle of doing an engine rebuid, my thread for this is http://www.mkivsupra.net/vbb/showthread.php?t=158179 for extra info. Basically up to now, I have found found 3 cracked piston rings and another seized one. There have been an odd couple of oil leaks as well, but a full list of details of my problems can be found on the above link. I will be having the block rebored and I will be using oversized pistons (Wiseco 86.5mm)

My car and aim for it

1) My aim is to stick at running 1.2 bar as Dash Rendar (pre owner) said he was advised not to go over this.

2) My car is BPU with the above turbos

3) I have no plan on increasing the power.

4) Now and again, my car went over 1.2bar, even with the restrictor ring?

5) I dont want to run less than 1.2bar, so didn't really want to put a smaller ring in as I would loose power plus doesn't it increase your egt's, which may not be a good thing. (I may be wrong on this point)

6) I will have a bored out block, most likely to 86.5mm using Wiseco.

7) I have a Aeromotive Fuel pressure regulator. I am not sure what these do, what its meant to be set out or anything. Who would know?

8) As my engine is apart, all gaskets and seals will be replaced, along with a few other stock parts most likely.

My queries:

1) People have said that I should upgrade to 550 power enterprise injectors as the stock 440's or what ever they are wont be up to the job. They will be nearly if not maxing out and this is Bad. My question is Why this is bad, and what do they mean by maxing out? What possible reasons are there for upgrading injectors in my case?

2) The E-manage thing. What exactly is it. Is it a boost controller or what? I dont know? Some people said I should get one, others said I should be fine running on stock injectors and nothing else.

3) People have said the car will need to me mapped once back together. Again, why is this etc and what info will this give me apart from BHP figures?

4) I am slowely uncovering the faults with my car as im going along (ie cracked piston rings) but I am unsure as to why this happened. Any ideas?

Few questions there, so thanks for reading and hopefully some of you techy blokes can shed some light on the above.

Thanks once again

Dave

Hi Dave.

Emanage http://www.driftworks.com/forum/parts-sale-private-sales/65789-trust-greddy-e-manage-ultimate-emanage-e-manage-ecu-kit.html

An electronic control unit that can be mapped to suit the cars modifications. Improving fuel, air, temps etc.

440 cc injectors will be right up to the full duty. ie delivering the max amount of fuel they can. If the engine load goes past this then the injectors will not be able to deliver the fuel to cope with the demand. Everything will change for the worse then as the whole balance will be upset.

Monkey3 has just the 440's and a restrictor ring. Boost does go over 1.2 when it's cold. There is no other control. Only way to get the boost you want is to get a boost controller.

Hope this has helped a little Dave. You don't actually need the bigger injectors and ecu etc. It would be preferable if you did.

So is what your saying is it would be best to have 550's injections, plus the Emanage Ultimate (to be on the safe side) and then to have a boost contoller as well?

So basically the Emanage will manage all fueling stuff, which im guessing would be set up by a car tuner? Also where does the areomotive FPR come into all this?

So is what your saying is it would be best to have 550's injections, plus the Emanage Ultimate (to be on the safe side) and then to have a boost contoller as well?

So basically the Emanage will manage all fueling stuff, which im guessing would be set up by a car tuner? Also where does the areomotive FPR come into all this?

They will be "nice to have" mate.

Out of the list, if price is a concern and when isn't it, I would opt for the 550's as per uk spec cars.

The boost controller. So you can make sure you don't overdo it.

Get a couple of gauges, AFR, boost and exhaust gas temp. You don't need anything else for safe bpu. You don't actually need the gauges but I like to know what's going on and if problems arise later those readings will help the real techies here sort it out.

The fuel pressure regulator does exactly what it says on the tin. The pressure is already regulated so that's a nice to have.

One thing though, I assume you have a fuel cut defender if you are bpu. Car hits fuel cut at 1.0 bar otherwise.

I agree with what Andy is saying, but none of those items are required, they are just nice to have and could be considered the "proper" way to go BPU as it gives a safety margin. The cost is very high though for little/no performance increase

Provided the engine is in good shape and you treat it well you can run 1.2bar on 440 injectors and no boost controller for as long as the turbos hold out. Many here have been doing it for years and 30k+ miles without issue.

Thanks Homer. I do tend to err on the safe side.

As I said Dave, Russ, Monkey3 runs none of the above and has 398 at the crank. No probs yet.

Cheers guys. My car does have a thor fuel cut defender by the way.

I am just trying to think of how I could of cracked my piston rings etc. And at times my car did see more than 1.2 bar, which it shouldnt as it had a 1.2 bar restricotr ring in place.

Any clues?

As for the engine once I have rebuilt it 'should" be in a good state.

It will have new gaskets, bearings, pistons and rings, and other stuff thats required along the way.

IMO out of all things mentioned, you would see more benefit by fitting an Emanage Ultimate (as said this is a piggyback ECU to fine tune engine running parameters) and having it mapped for the boost you want to run,with this is done you will be very unlikely to see more than 80% injector duty cycle,85% is considered to be the maximum DC you would comfortably want to see, although some advocate 90%.

In any case you could always run slightly higher fuel pressure (Aeromotive fuel pressure regulator) to increase the injector yield.

For example even running a GT4088 turbo at 1.1 bar and EMU i don't see more than 75% DC with 540cc injectors.

As for the causes of you're broken rings, they can be caused by any number of things, eg, oil starvation, detonation, overheating, or just plain fatigue.

Dave, the restrictor ring is not a definite. It's just a sized hole that allows a certain amount of flow creating a certain back pressure. All of that can vary with the air density on the day.

If it's colder then you get more boost. Or if the ring size is slightly off then you can get more boost.

1.2 bar on a warm 23 c day may be 1.25 bar on a cool 10 degree morning.

As Tricky says for the damage.

It's why I err on the safe side. I don't know about the duty cycles of the injectors etc off the top of my head which is why I don't quote it, but when people like Tricky explain it like that, I know what it means and why I'd use the 550's instead of "maxing" the 440's.

Thanks for all the info guys, its appreciated!

If it has broken rings it's almost certain they'll have been caused by det, or damage removing the pistons if water has entered the bores. I'd say det as you don't mention rusty bores.

If it has broken rings it's almost certain they'll have been caused by det, or damage removing the pistons if water has entered the bores. I'd say det as you don't mention rusty bores.

Just out of intrest Chris, how would I know/check if Det had occured. What are the signs?

Just out of intrest Chris, how would I know/check if Det had occured. What are the signs?

Broken rings

Broken rings

I guess I asked for that.

Any other signs then?

Just out of interest, will the UK oem 550 injectors fit straight into a Jspec supra to replace the 440cc ones?

Edit: Just been told they will fit but ill need to fit a UK resistor pack. Basically it will need to be wired into my wiring loom in the bonnet, just in front of the passenger side of the windscreen.

Would you say this would be as good as just getting some 550's enterprise ones?

Chris, (or anyone else in the know)

After doing some research on Detination, I came across this thread http://www.mkivsupra.net/vbb/showthread.php?t=22180 which gives a few reasons on what could cause detination.

Up to now, having totally stipped the engine completly, the only thing we have found wrong is that it had cracked pistons rings. Looking at the pistons themselves there doesnt seem to be any phsical damage ie nothing is broken, however the top end around the the piston rings are blackened. (See Pic)

As for the bores, there is no gouges at all, and they were oily as you would expect them to be. There is no sign of any rust either.

My question is, what could of caused det, and does it still sound like I det has occured?

Could my current set up (ie with 440 injectors) contributed to this?

If there was any significant det on you're engine, you would usually see signs of this on the edge of the pistons and head, it usually takes the form of lots of tiny indentations in the milder form, and complete erosion in the extreme cases, if there is no signs of physical damage to the pistons then i would doubt it was det.

Hmmm Still puzzled in that case as there doesnt seem to be any signs of indentations