Intake Manifold Porting and Injector upgrade

[softopz]

So I have the intake manifold pulled out ready to throw on the supra 440cc injectors. I was planning on port matching the the manifold to my already ported head. I had a couple of concerns on what O rings/ seals to use.

 

 

To the left I have the zxt injector and the right the supra injector. Notice how the zxt injector protrudes more in to the manifold than the supra injector. Will this be a problem? I am thinking the fuel is going to spray against that wall and drip into the head instead of atomize. Since Iam going to port the head I was thinking of just removing that materal is my logic right?

 

The second thing is which seals to use? I read in the injector upgrade thread

"Toyota Supra 1987-1992 - This is an o-ring injector 11mm. Injector electrical clips need modification or swap. Use stock seals at manifold and not the Supra seals."

 

I tried that but it will make it protrude less. Is there a need for injector body mounts? How about sealing where the rail meets the injector do I need another Seal there...or the one on the injector is all there is?

 

I got my injector plugs and O ring fuel rail I was going to bench test everything especially after porting to see the spray patterns and all I will take pics and document it for the forum.

[softopz]

My logic is quite simple better atomization better mixture = better ignition burn. especially with a bigger injector and 4 spray pattern, at idle I imagine this will drip down in head and cause a rough rich idle.

 

 

I have already ported my head similair to this pic from Braaps thread on big and nasty head work. However not as aggressive and nice as a port job. I ll take some videos/pics of mine with stock injectors mounted to intake manifold spraying in a clear platic box, then Ill do the same test with the supra injectors. I will then repeat it with the manifold ported and injector body shortened. If anyone could chime in maybe stop me if this is a bad idea hehe or maybe some opinion or specifically how I should shape the walls of injector body...specifically the end I notice they all have a crease in them probally to give it a pouring/ spraying affect.

[PalmettoZ]

So I have the intake manifold pulled out ready to throw on the supra 440cc injectors. I was planning on port matching the the manifold to my already ported head. I had a couple of concerns on what O rings/ seals to use.

 

 

To the left I have the zxt injector and the right the supra injector. Notice how the zxt injector protrudes more in to the manifold than the supra injector. Will this be a problem? I am thinking the fuel is going to spray against that wall and drip into the head instead of atomize. Since Iam going to port the head I was thinking of just removing that materal is my logic right?

 

The second thing is which seals to use? I read in the injector upgrade thread

"Toyota Supra 1987-1992 - This is an o-ring injector 11mm. Injector electrical clips need modification or swap. Use stock seals at manifold and not the Supra seals."

 

I tried that but it will make it protrude less. Is there a need for injector body mounts? How about sealing where the rail meets the injector do I need another Seal there...or the one on the injector is all there is?

 

I got my injector plugs and O ring fuel rail I was going to bench test everything especially after porting to see the spray patterns and all I will take pics and document it for the forum.

 

 

Hey softtopz-

Isn't the Supra injector designed for a 4 valve head, which means that the spray pattern will be split spraying towards each intake valve ? This means that the way the Supra injector shown in your photo will have the spray going towards the sides of the hole the injector is sitting in.

[jc052685]

what ems are you useing?

[PalmettoZ]

This is what I was refering to with the split spray pattern of the Supra injector.

 

[jc052685]

Unless its a sequential EFI it does not matter.....

[PalmettoZ]

Unless its a sequential EFI it does not matter.....

 

 

What doesn't matter? I'm missing your point.

[jc052685]

ANY of it....

 

Spray patterns, where it sprays, how it sprays, at what angle. It will all end up pooling on top of the valve until the valve opens thus misting it into the cylinder.

[PalmettoZ]

ANY of it....

 

Spray patterns, where it sprays, how it sprays, at what angle. It will all end up pooling on top of the valve until the valve opens thus misting it into the cylinder.

 

 

Your so wrong on that statement. If that were the case then why manufacture injectors that spray differently. How the injector sprays makes a big difference in performance. The Supra injector can work here but it is the wrong type for the application.

[cygnusx1]

If the squirt is timed with the opening of the valve it makes a difference. It is less so if the injector is squirting at the back of a closed valve.

[BRAAP]

ANY of it....

 

Spray patterns, where it sprays, how it sprays, at what angle. It will all end up pooling on top of the valve until the valve opens thus misting it into the cylinder.

 

Your so wrong on that statement. If that were the case then why manufacture injectors that spray differently. How the injector sprays makes a big difference in performance. The Supra injector can work here but it is the wrong type for the application.

 

You are both right.

 

Due to the Z car injector spray pattern being a stream that will squirt approx 24”-48” vs a nice fine mist spray, it is sprayed directly at the back of the intake valve, (chamber wall if the valve is open), it doesn't make much difference as the stream is hitting the valve stem, back of the valve and chamber wall, i.e. not fully atomizing in the air stream before it enters the combustion chamber. As such, jc052685 is correct.

This shot looking down an injector port into the cylinder head at the back side of the intake valve/stem.

 

 

PalmettoZ is also correct in that the newer more modern Fuel injection systems, (vs the early Z car EFI), injector spray pattern, point of injection and aim of injection have become more specific, engineered, to the point of even incorporating sequential injection, to take advantage as best as possible, all the attributes that contribute to fuel atomization prior to the combustion event.

 

Some injectors atomize best when the stream is sprayed against a hot metal surface such as the back side of the intake valve or port wall near the valve/chamber, others offer better atomization being sprayed down the port to get as much contact time in the air stream for optimum atomization.

 

 

 

Back to jc’s point, we see it all the time in Motorsports where the injector will be aimed directly at a port floor, not down the port as logic would dictate, and it works fine, i.e., spray pattern, aim, etc really doesn’t matter, the engine will run within 1-2% of ideal either way.

Aimed at the port floor;

 

 

Sequential injection. The benefits of sequential are only realized with an injection system engineered with an injector spray pattern, aim, and injection event timed tot he intake valve, and the benefits are most notable at idle and light throttle, i.e. mileage and emission reasons, not power reasons. This aim may be at the back side of a closed hot intake valve or when the valve is open to inject directly into the cylinder, (not against the cylinder wall as that causes cyl wall fuel washing which is a bad thing). At WOT, no real benefits for sequential vs batch. Stop and think about it for moment and you’ll understand why. An injector pulse width at WOT with an appropriately sized injector will have a duty cycle of approx 80%. That means that approx 80% of the injectors life during WOT is spent open spewing fuel into the port.

The intake valve is NOT open that amount of time during a complete combustion cycle, which is 720 degrees of crank rotation, (2 crankshaft revolutions). A cam with 240 degrees of duration leaves the intake valve open for only 33% of the cylinders cycle, so a good portion of the time that the injector is open during WOT, fuel is being sprayed into the port behind a closed valve as well as when it is open! It is during light load and idle where injector pulse widths are small, all within the total time the intake valve is open or closed as the design timing may be, for full effectiveness of what sequential injection has to offer. Again, that only really counts for a system with the injector location, spray pattern, aim, and open time vs intake valve timing are engineered together.

Edited November 18, 2009 by BRAAP

[BRAAP]

Back to the original topic,

Depth should not be that big of deal within reason of course, as the spray pattern should miss the injector slot in the head and spray down into the port.

 

Now the Supra injector appears to have two ports aimed off center for the split ports of the multi valve head. My guess is the Supra injectors are possibly further away from the valve itself vs the Z, so its angle might be quite narrow. If that is indeed the case, the spray pattern could then be wetting the port walls, but probably not make much difference in overall power output, as noted above, would mostly affect light load conditions, and the affect may be negligible at that. You’d be amazed at how much variation in pattern/aim can be made before a measured or seat of the pants difference can be felt.

 

In short, I wouldn’t be afraid to try them, don’t worry so much about mounting depth as it shouldn’t affect it adversely, it will land it where it lands unless you modify the manifold.

As for the fuel rail, so long as the fuel rail receiver hole is the correct size for the Injector O-ring, it will fit and should seal just fine. The injector will “float” it he fuel rail.

 

Hope that helps,

Paul

Edited November 18, 2009 by BRAAP
Typos.

[spacecase70]

Back to the original topic,

Depth should not be that big of deal within reason of course, as the spray pattern should miss the injector slot in the head and spray down into the port.

 

Now the Supra injector appears to have two ports aimed off center for the split ports of the multi valve head. My guess is the Supra injectors are possibly further away from the valve itself vs the Z, so its angle might be quite narrow. If that is indeed the case, the spray pattern could then be wetting the port walls, but probably not make much difference in overall power output, as noted above, would mostly affect light load conditions, and the affect may be negligible at that. You’d be amazed at how much variation in pattern/aim can be made before a measured or seat of the pants difference can be felt.

 

In short, I wouldn’t be afraid to try them, don’t worry so much about mounting depth as it shouldn’t affect it adversely, it will land it where it lands unless you modify the manifold.

As for the fuel rail, so long as the fuel rail receiver hole is the correct size for the Injector O-ring, it will fit and should seal just fine. The injector will “float” it he fuel rail.

 

Hope that helps,

Paul

 

BRAAP is the man when it comes down to building power from the L- series engines, his advice is that of a sage! follow him and youwill be on the right track!

Edited November 18, 2009 by BRAAP
BRAAP's typos...

[softopz]

palmettoz exactly thats my concern with more than one spray pattern it will be wetting the walls and dripping down . Thats why I want to port the intake manifold but before that document it before and after

 

I am running MS2 all I have to do is put in the settings for the 440'cc, you guys all raise good points. My original concern was dripping/wetting of the walls and it not running to its full potential. I complelety agree with you BRaap the difference will not be that big when driving aroound pulling loads of vaccuum or loads of boost. However this is more intend to having a nice clean, smooth burning idle and not stinky. I am going to go ahead and port the manifold since the head has a nice little port job. I cant go to as far as more than 3 inch's inside runners cause of limited tools, it wouldnt hurt.

 

can anyone confirm the sticky? use the stock zx seal at the manifold. Some members said they bought a seal kit and just use different ones.

[Tony D]

Spraying onto the port wall builds a puddle, the aim of the EMS is to keep this puddle consistent so as to have proper fueling during transient activities. When you rapidly open the throttle valve this 'tau' layer of fuel will evaporate rapidly and then afterwards create a transient lean spot. The 'accel pump' feature of many ems compensates by using rate of throttle position travel to preload this wet layer for the ride through of rich-lean-injector lag time... When you have a wet puddle there, it has to be there or you will have a heluva time getting the mixes right.

 

As long as the puddle remains constant in size, AFR's will remain stable. The trick is at lower openings is when the changes of throttle angle are the most severe and the flow differences effecting the puddle can be drastic. This is where sequential shines.

 

As long as the puddle on the runnner remains CONSTANT, it will not affect you---it's like it wasnt' there. You will be able to run and tune around it...it will make cold starting easier, but hot restarts slightly more difficult (depending on time after shutdown of the hot restart). I read a nice article by a guy from GMI about this puddle effect and how it works, it really made a lot of sense from the standpoint of understanding why the aftermarket EFI stuff does what it does. Basically his statement was you make the puddle, then you maintain it. The closer you are to keeping the puddle the same size all the time, the better the car will run and drivability will not be affected.

 

Really, these cars won't smoke black out the tailpipe till low 10's in the AFR... visual clues of smell and smoke are llong since gone for real tuners, you need instrumentation.

 

Sealing of the injector tips is a cheap check: the seals are $3 at Autozone, buy a set find out and post the results. The Stock stuff goes around the pintile higher up than you think. I have taken standard o-rings and slipped them on the pintile cap and had them seal just fine. It's pretty forgiving, like BRAAP said, they float, all you need to do is apply a little pressure and they seal. For $3, for the whole set of 12, even if you are throwing the big body units away----why not try and put it to rest for certian?