Small motor, BIG injector and idling

butlerbmx (at) yahoo (dot) com if anyone wants to get some ideas moving...

Don't watch PW just watch the duty cycle if its above 90% at a reasonable AFR then upgrade.

erohslc wrote: I think a problem with a rising rate FPR would be getting the MS to play nice. Not impossible if you are a bit twiddler, just something else to fiddle with. As for injector spray pattern testing, *don't use gasoline*. Mineral spirit or similar low volatile, into a large glass jar or a plastic tube is easy to observe, with suitable background. Consider video of your testing..

I've heard Naphtha is best for low volatility and similar flow properties to gasoline. Black background and a camera with the flash on worked really well for me.

So that's one hole in the head for all 4 cyl? Interesting.

One thing I want to confirm- you are injecting 4 times per cycle, right? That should help some in terms of distribution. You can mess with the timing to see if that helps keep the fuel overlap down some. And as odd as it sounds, a warm manifold will help- evaporate the fuel and heat the injector.

The pattern is more important cold than hot- once the injector gets hot enough, it flash vaporizes on injection- which is good. Puddling isn't bad assuming the system is designed like that- like a basic carb replacement. It will spread out from there. For this- if the wet spray is just on the outer wall- I would guess that 2 and 3 would get more than 1 and 4.

Do you have one of those infra red "guns"?

Basically, it's a like a log style manifold that's integrated into the head, a plenum area with 4 ports and one source hole. The firing order is 1-3-4-2 ? That means it's like the siamesed port intake manifold problem. Each 'branch' see's 2 intake pulse together (3-4, 2-1) followed by 2 dead times. If you could open up the single intake port, and then add a divider to the plenum floor, you could run 2 independent intake runners (and 2 injectors). Could join the runners together somewhere before the throttle body, or run twins.

4 times per cycle will help with distribution, but harm with the idle pulsewidth issue.

I am actually set a 2 injections per cycle. I will try 4.

Will this change the VE table needs? Will I have to start all over?

The throttle body is heated with coolant and yes it does tend to idle better when good and hot.

Verified last night that the duty cycle is not going too high. Just over 60% at max load.

Totally fine for now. Just multiply your current injector size by your desired future pressure ratio (lb boost + 14.7)/14.7 to get to your new injector size needed.

No idea if you have to change the ve tables- hope not since the system is more physics based so a simple injector change should be easy...

And if the a/f is good- add more spark.

E

Ditchdigger/cghstang...Here is something along the lines of what I was thinking... Let me know if you (or anyone else is interested. Contact the email above. I dont think I would charge for this (at least not the first few victims...I mean "clients", yeah clients). theres some info I would need, but we can discuss that outside of the forums or in a another thread.

4cylndrfury wrote: Ditchdigger/cghstang...Here is something along the lines of what I was thinking... Let me know if you (or anyone else is interested. Contact the email above. I don't think I would charge for this (at least not the first few victims...I mean "clients", yeah clients). there's some info I would need, but we can discuss that outside of the forums or in a another thread.

WOW I am impressed Great work!!!!! I hope GRM is watching as that would make an interesting page or three for the magazine. Hint Hint Hint!!!!.

dean1484 wrote:

4cylndrfury wrote: Ditchdigger/cghstang...Here is something along the lines of what I was thinking... Let me know if you (or anyone else is interested. Contact the email above. I don't think I would charge for this (at least not the first few victims...I mean "clients", yeah clients). there's some info I would need, but we can discuss that outside of the forums or in a another thread.

WOW I am impressed Great work!!!!! I hope GRM is watching as that would make an interesting page or three for the magazine. Hint Hint Hint!!!!.

While I would LOVE to take credit for that work, thats just a link I found in my casting studies - unfortunately thats not a piece of my own. But I am certain I can repeat those results as i have the necessary equipment and have done similar work, I just havent had a head to use. i might take a trip down to the pull and pay yard to nab a random head and take a shot at it though. I would just like to have a running car to take a shot at making a manifold - would love to see a cast piece of my own used on track somewhere!!!

Maybe you've seen this one (caution, many pages, bring a drool cup):

http://forums.hybridz.org/index.php?showtopic=63445

Derek's DIY cast IR manifolds for a 240Z.

ISTR finding this link on the GRM Forum.

I'm into DIY foundry myself, but I'm leagues behind ....

This is a great casting thread. http://vagdrivers.net/forums/index.php?showtopic=39794

4cyl I will try and get some DXF's drawn up this week. Or I could just send a gasket or a stock manifold.

The jubilee clamp on the throttle body needs to clip on to a round surface with a retaining groove. I turned mine on a lathe.

I could machine another out of delrin or aluminum or something in the proper oversize so that you could use it for the mold

ditchdigger wrote: Going back to the stock cam for boost

Don't do that. You'll just kill some of the horsepower you're trying so hard to make.

ha! I check that VW forum almost daily just for that thread!

A decent image would be fine...my guess is shipping anythign from oregon to Ohio is gonna be rough. A round plate you turn could be bolted to the end of my casting as well since it would be tough to cast the groove, and Im betting a manifold wont fit your lathe. Whats the OD of that round plate? Besides the gasket dimensions, and the diameter of the junction plate, I would need to know how tall the overall manifold needs to be off the head, and any other dims you feel like tossing in. Use my email if need be

zomby woof wrote:

ditchdigger wrote: Going back to the stock cam for boost

Don't do that. You'll just kill some of the horsepower you're trying so hard to make.

The more I read the more the idea of a big cam on this motor is a bad idea. Cam overlap+Siamese ports=charge robbing on an epic scale.

http://www.starchak.ca/efi/siamese.htm

After reading that I get a better idea about what is going on .

4 squirts per cycle ran horribly. Very rich and bogging out all over the place. But according to those more knowledgeable on injecting siamese port motors I need to get it working. I guess I have to start all over.

Having done it more times then I'd like to count, starting over is always easier then the last time.

Sucks that the time and resources spent on the dyno are a write off though.

If the weather is cool this week I am yanking the motor to swap the cam back. Then I will start over.

What is a good junkyard/GRM source for random turbo plumbing hoses and couplers?

ditchdigger wrote: Sucks that the time and resources spent on the dyno are a write off though. If the weather is cool this week I am yanking the motor to swap the cam back. Then I will start over. What is a good junkyard/GRM source for random turbo plumbing hoses and couplers?

Volvo 740/940 Turbos.

ditchdigger wrote: Sucks that the time and resources spent on the dyno are a write off though. If the weather is cool this week I am yanking the motor to swap the cam back. Then I will start over.

Write off is relative. What you have doesn't go away 100%- you have A solution to the problem- it runs well enough.

If you were not going to take out the current cams, I would have suggested trying to find an injection paramter that you can cut in half- that would get your original cam calibration pretty close.

Then again, starting with that suggested calibration will also probably be a really good start, too. If you have a Wb that you trust, just go driving, and try to run the autocal to get it closer. For the 95%, you'll need to hand tweak, probably, and 100% will need the dyno.

Again, not a write off. (doing my best to reduce the suckiness)

(and don't be afraid of the spark! )

NOTE:

Just got the required sodium silicate for core making (making the hollow part of a casting). If anyone wants a manifold made for free (I cant promise anything about performance gains or fitment quality), use my email above to discuss details. If I have read the rules right, since this offer is made to the public, free is free and the part counts nill to the bottom line of a challenge budget.

I only go to the dyno if something is obviously wrong with the street/track performance and I want to look at it while it's 'moving'