Wet manifold injection V2.0
Turbo Mini Forums

It is embarrassing, such slow progress…
But I have found some courage to post again about my plans and bits of progress and hope you are willing to give me some more advice.

So, too much time has passed; work, house, changing nappies...
Other reason was having to borrow a TIG welder from a friend every time but that has now been solved:

Simple (only DC), relatively cheap but has all options I need for now.

I will be making a wet manifold using 2 injectors; I know it’s a compromise with de Siamese code available but I for the moment I will settle for this as progress is already so slow.

Next steps:
- Injector placement
- Selecting injectors
- Further fabrication of tubing / manifold

Injector placement:
This is how I plan to position them:

The angle and height are a bit of a guess; the info I can find on the web mainly covers positioning of injectors for port injection. For wet manifold I saw some at 45 degrees so followed that.

Selecting injector:
The Siemens Deka 630cc/min has caught my eye.
This should be more than sufficient for 130hp with some reserve for possible changes in future.
Pulse width calculator gave approx 2.1ms for idle which would be in the linear region of the injector curve.
Have read the “dead time” post by Paul S which has some info about the 630 aswell which is a bonus..

Further fabrication of tubing / manifold:

I plan on making a ‘divider’ for dividing flow in the 90 degree bend to prevent airflow concentrating on the outside of the bend and optimise charge mixture a little bit.
I will be making some flanges for TB and recirc valve (practice welding with my TIG).
Also working on a construction for the suction side of the supercharger.

Can I ask you please to comment on injector choice and position and angle of the injectors?

Dazed and Confused....

The injector size is more than enough but remember that you'll want to run the injectors in a 4 squirts/alternating mode with your wet manifold. That means each injector will pulse once per rev so you can't use as big a duty cycle as you would if it were once per cycle due to the additional dead time period.

One thing I don't like about the injector placement is that each injector favors one intake port. Since each injector will need to provide fuel for all cylinders, there is a risk of having a worse AFR distribution than could be possible with a better placement. The best would be if they were at 90 degrees from where you show them (front and back instead of left and right as shown in the picture) but I don't think there is any space for that due to the supercharger and firewall.

If you could find a way to place the injectors so that both injectors 'see' both intake ports in a similar way, you will have a better chance of having a decent AFR distribution (within the constraints of a wet manifold, of course).

Jean

http://www.jbperf.com/

Thanks for your reaction Jean.

Space indeed was the constraint.
I had another look and what I could do is position the injectors at the outside corner of the 90 degr curve.
Like so:


This would mean I would have to reduce to vertical bit which I was hoping to avoid because I fear that the 90 degree turn close to the 'T-split' would also result a favouring one port..
Maybe re-shaping to 2x 45 degree and creating a divider will be helpful.
I am going to try and get dome cfd simulations of different shapes, that might be helpful.

Thanks again for your comments.
Han

Dazed and Confused....

With a wet manifold of sufficient volume, with enough squirts per cycle, and the injectors more than 6 inches from the ports it doesn't make a significant difference where you stick the injectors in relation to the ports. Mine has 4 smaller injectors in two banks at one end of a wet manifold and I see no AFR difference between inner and outer cylinders or either port.

You suggested positioning on the bend looks great, you can even get 2 injectors side by side like mine of you have 2" pipe.





more pics in the album, and I'm adding some this weekend as the manifold has changed (very slightly)..

Jamie, I agree your design will mostly eliminate any inner/outer differences under a wet manifold situation but I would really like to see your inner/outer AFR plots.

Paul and myself have recorded quite different AFRs on test with just a standard (normally aspirated) HIF44 setup.

Where are you actually measuring the inner/outer AFRs, obviously it's a bit different with a turbo but I can't see either of the widebands in your photo (presumably it was taken before you fitted them).

An updated picture of the exhaust would be usefull.

Edited by Rod S on 25th Aug, 2011.

Schrödinger's cat - so which one am I ???

It's 1x EGO in the downpipe on this car at the moment. We are building another car which has 3x bungs in the exhaust manifold. I tested this inlet manifold on the other car to see how it was before running it on mine (and we tried another design more similar to the one Yo-Han has which it will run). I'm not running three sensors all the time as it's not something I need to know day to day. I'll swap exhaust manifolds back around at some point and get some plots once I've fixed the other problems I'm having with intermittently losing the tach signal whenever tuner studio is open, which is rather holding up the job at the moment. Just got a V3 Microsquirt to try out.. the saga continues...

Not quite sure you can see no difference between inner/outer AFRs with only a single LSU (although Innovate do claim you can scope the single LSU and see individual pulses....) but it would be interesting to see how you are intending to do it on a turbo setup (the LSUs will surely die if you put them before the turbo straight into the manifold). Paul, myself and Graham have a sample tube arrangement to keep the LSUs at the correct temperature so I would like to see what you are intending.

Tach signal loss is a standard feature of the standard MS2/3 V3.0 mainboard :)

The Microsquirt appears to use the same circuitry and doesn't allow access to the CPU pins so prevents you using a better VR circuit.

Jean's new board (once you figure out how to work it :) ) is much better, or the LM1815 circuit (from the MS-Extra manual, or Jean's original board) are a lot better IMO.

Schrödinger's cat - so which one am I ???

The tach signal is brilliant as long as tuner studio isn't running. That's the bit we are working with the MS guys to figure out. F few people are having the problem and they can't replicate it..

On the other point LSUs are fine for a short time straight off the port. As I said it's not staying there. We are going to try scoping for individual pulses too as it saves a lot of welding and spannering moving stuff around to test each mad new idea. I'll let you know how it goes.

TBH it might never see the road in it's current form and end up sequential. It all depends on how it performs when finished. Plus it gives me a chance to use the cam sensor I knocked up the other day with a dinky little 36-1 wheel in a dizzy casing and an opto sensor. Pictures of that after the weekend...

Interesting.

Try an earlier version of TS, I refuse to upgrade because of all the problems (but there are other, different, issues on the earlier versions).

I think LSU life would be seriously limited, and the actual output data not reliable, if run outside Bosch's temperature limitations, AND, more importantly, the pressure limitations.

Have a look at the Bosch data and you will find the LSU output is seriously affected by pressure (ie, before a turbo).

Just my opinion though.

Why a 36-1 wheel for the cam signal if you are considering sequential ???

A plain one gap wheel on an optoswitch works fine



That's all the MS2-Extra (siamese) code expects, one pulse per cycle (one pulse per two RPM).


Sorry Han, we are rather moving away from your original question :)

Schrödinger's cat - so which one am I ???

On the subject of widebands pre turbo, AEM have a new offering which looks interesting

http://www.aemelectronics.com/wideband-air...-controller-60/

Using that with a pressure sensor will let you measure AFR's pre turbo.

Although it's not cheap, it might help people with space issues for sample chambers.

That's interesting but with the number of people having trouble with calibration with AEM units, I'm not sure I would trust the output if you add the non-standard pressure compensation.

Jean

http://www.jbperf.com/

Cos I'm trying it as a crank sensor at the moment. Plus It could end up doing both jobs, but not really thought about that much yet... can't get my head round that.

Yes, thread hijacked! We can continue on my build thread when I update it. Sorry!

A 36-1 cam wheel will work for sequential but you'll lose precision compared to a crank wheel due to the slack and play in the cam drive.

Jean

http://www.jbperf.com/

Schrödinger's cat - so which one am I ???

Haha, don't worry about it..

Actually it's an interesting read, have to get up to speed with Megasquirt and it's functions eventhough I signed up for Jean's built ECU project.

I will have another look at your build thread Jamie, thanks for your comments (You too Rod).
(Actually there are 2 injectors side by side in that picture.. )

Han

Edit, spelling

Edited by Yo-Han on 25th Aug, 2011.

Dazed and Confused....

Was looking around on the web for suitable injectors.
Found these:
http://yourperformancesource.com/index.php...1&products_id=4

Short style would suit me very nicely; any obvious issues that I should be aware of with these (short style) injectors.
By the way injectors are cheap in the US! (being dutch, I like that...! )

Dazed and Confused....

I'm using the 60lb and 80lb Siemens injectors in the Miglia, but long style. Working OK although it's early days.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

Thanks for that Paul.
Might just order some.
Saw your thread about Santa Pod, real shame.

Dazed and Confused....