Cyl 2 and 5 lean, This is how I fixed

[Alan L]

Wow - good stable result across top end. I am envious.
Well done. You can run more boost now :-)
Alan

[heliolps2]

Originally Posted by Alan L

Wow - good stable result across top end. I am envious.
Well done. You can run more boost now :-)
Alan

Right ! I would of killed for these numbers on my old yellow 911, I haven't checked my boost numbers since I replaced the wastegate spring with the RUF 0.9 bar spring, I'm sure I have a little boost creep with no cat. I'll have to hook up my test boost gauge now and see how much boost I'm getting, I can always reinstall the manual boost valve and go to 1 bar, Its seems that I have room, your thoughts?

[Alan L]

I run mine to 12.5 AFR at 1 bar and am quite comfortable with that.
But I would be nervous pushing it further. Hours on the track at WOT at those settings and several teardowns in between show no issues.
Regards
Alan

[heliolps2]

Originally Posted by Alan L

I run mine to 12.5 AFR at 1 bar and am quite comfortable with that.
But I would be nervous pushing it further. Hours on the track at WOT at those settings and several teardowns in between show no issues.
Regards
Alan

What hardware are you using? Not sure how much boost the stock hardware /bolts can handle ?

[RarlyL8]

Nice job as always Helio!

Alan, here is something that may be an option for you. The unequal air distribution caused by the unequal length intake manifold runners can be taken advantage of, or more accurately, compensated for if using a 7th injector. Fuel is sprayed into the intake which will distribute more fuel to the 2&5 runners that also get more air. This only works on boost but that is when it is most needed. These engines can go 100k+ miles when street driven not seeing much boost, so the unequal AFRs are not lethal in that situation. You have the skills and knowledge to meter it accurately if want to give it a shot.

[Alan L]

Originally Posted by heliolps2

What hardware are you using? Not sure how much boost the stock hardware /bolts can handle ?

I think my studs are ARP. Been a while since I fitted them, but I recall some torque instructions for the heads which I think are different to the normal process. I have stock rod bolts - I know that because the ARP ones are sitting in a packet on a shelf.
Tell me about your black 320ml FD and 009 injectors. I think the 009s are a size up from stock? What does the 320ml black FD refer to (Euro modded?)
Alan

[Alan L]

Originally Posted by RarlyL8

Nice job as always Helio!

Alan, here is something that may be an option for you. The unequal air distribution caused by the unequal length intake manifold runners can be taken advantage of, or more accurately, compensated for if using a 7th injector. Fuel is sprayed into the intake which will distribute more fuel to the 2&5 runners that also get more air. This only works on boost but that is when it is most needed. These engines can go 100k+ miles when street driven not seeing much boost, so the unequal AFRs are not lethal in that situation. You have the skills and knowledge to meter it accurately if want to give it a shot.

Yep - that is something I am pondering on at the moment -rpm switch, extra injector. Any extra fuel will help - even if not distributed equally. It is only the last few % I am looking for so any imbalance should not be lethal. If say some intakes get 5% more and others 10% more, 90% of the fuel is equally balanced so the final imbalance for a transient moment (last 500 rpm) should not be a huge issue. Not as ideal as Heliops outcome, but has to be progress.
Regards
Alan

[RarlyL8]

I would use a Hobbs switch in conjunction with RPM control to activate the injector at a preset point when the AFRs rises to 12.2 on boost. Oxygen sensor control trigger would be even better. Fueling of the 7th injector could be adjusted to maintain the target AFR. You also have the option to use MeOH/H2O if the rules will allow it along with increased boost, but that is another conversation.

[Fixer]

Hello I confirmed my #5 cylinder is receiving about 10% less fuel than the rest a while ago but left the settings as is.

I'd like to save some time and simply add fuel to #5 without removing everything I just installed recently.

Which direction do we adjust to add fuel? Theres is no mention of CW or CCW rotation. That would be helpful for people doing a search.

I confirmed looking at my exhaust port #5 in that it does runs leaner and looked at my fuel delivery test pic (from a year ago) that I attached here confirming less fuel delivery on #5.

I always assumed if I messed with one it would take from the others and decided at that time to leave it alone.

After seeing my exhaust port I'd like to add 8% to number 5.

I'd guess CW to add fuel but obviously I would never guess.

037 black Euro FD

Thank you.
Matt

[Alan L]

CW about 1/4 turn.
Alan

[Fixer]

Originally Posted by Alan L

CW about 1/4 turn.
Alan

Thank you Alan there doesn't seem to be information on adding /- in my factory workshop manual

[gsxrken]

Alan, a year late but thanks for this post. I ended up asking Len Cummings BoxterGT to make me some fittings up that allow me to use my CIS fuel pressure rig to perform this test. Since the fuel pump is 14m and the rig is 12m, he made up two fittings to step up from 12 to 14 and step down from 14 to 12.
All of this to figure out which fuel pump is not pulling its own freight, even though both are less than 4 years old.



Top is M12 Male x M14 Female, bottom is M12 Female x M14 Male.

Once these get plated so they don’t rust I’m going to offer them to 930 pelicanites on a loaner honor system. I hope to not need them again, and my kids will sure as hell not know what do with them when I’m gone.

Originally Posted by Alan L

My differential pressure thing is a home made cobbled thing - and I have the same issue as per fittings.
But the critical fitting is the one that hooks on to the fuel fitting at the end of the front pump line. - Mine came off the discarded fuel filter. It has a couple of fittings screwed in it - as it comes out of the box. One of them happens to be what you want.
Then I just cobbled what brass fittings I had that would fit.
If you grab the filter fitting (ball socket type fitting with a thread on the other end) (can post a pic), and take your pressure gauge - then the shop should be able to assemble enough bits for you to Tee the gauge in.
Regards
Alan

[Fixer]

Done, it felt like the same size allen head as the plug to adjust the adjuster. I was hoping for a more engaging feel to the adjuster, it's very easily turned but I did approximately 1/4 clockwise.

Going out for a test run.

Enjoy the weekend!!

Matt

[Alan L]

[QUOTE=Fixer;11667325]Thank you Alan there doesn't seem to be information on adding /- in my factory workshop manual

No - there ain't any info in there. Just my handwritten notes in my CIS manual.
Alan

[Alan L]

[QUOTE=Fixer;11667364]Done, it felt like the same size allen head as the plug to adjust the adjuster. I was hoping for a more engaging feel to the adjuster, it's very easily turned but I did approximately 1/4 clockwise.

Going out for a test run.

Enjoy the weekend!!

Mat

Wicked looking machine. The adjuster plug allen key is 9/64". Weird size. Close to (bigger) but not the same as the adjuster key - 3mm.
Hopefully you felt some pressure/resistance when turning. The 1/4 turn is just approximate - but you are heading in the right direction - so better than where you were previously.
Alan

[Alan L]

Originally Posted by gsxrken

Alan, a year late but thanks for this post. I ended up asking Len Cummings BoxterGT to make me some fittings up that allow me to use my CIS fuel pressure rig to perform this test. Since the fuel pump is 14m and the rig is 12m, he made up two fittings to step up from 12 to 14 and step down from 14 to 12.
All of this to figure out which fuel pump is not pulling its own freight, even though both are less than 4 years old.

Top is M12 Male x M14 Female, bottom is M12 Female x M14 Male.

Once these get plated so they don’t rust I’m going to offer them to 930 pelicanites on a loaner honor system. I hope to not need them again, and my kids will sure as hell not know what do with them when I’m gone.

You are welcome - Len is a good bloke. He has been hunting for some hard to find fittings for me too (Carrera M30 oil cooler bits).
Once you have that pressure differential unit made, it is a very simple test to perform - no more guesswork. From memory spec is between 2.5-4 bar.
Alan

[heliolps2]

Nice,

Sorry, I've been MIA, Looks like this thread is still helping people. Thank you, Alan, for staying on top of it.

[boosted79]

I like to use a digital scale to weigh each bottle rather than comparing levels visually. I use plastic bottles because they are light and usually weigh exactly the same. Then I tweak #2&5 to add 4%. Still have to do a vis check on the headers.

[heliolps2]

Originally Posted by boosted79

I like to use a digital scale to weigh each bottle rather than comparing levels visually. I use plastic bottles because they are light and usually weigh exactly the same. Then I tweak #2&5 to add 4%. Still have to do a vis check on the headers.

That's a great idea.

[Alan L]

I use a measuring cylinder - good to 0.5ml (cc). Collect about 60-70 cc.
You need to be accurate with these if you are trying to tune the FD to better than average numbers.
Porsche manuals sometimes suggest a 10-15% tolerance between cylinders is OK. For NA cars that may be OK - and my SC is such a beast. And if you read the threads - plenty complain about the engine bucking/missing at low revs and light throttle settings. Apart from eliminating any airleaks, another likely issue is a cylinder leaner than the others - 10-15% leaner. I recently tuned my SC FD to 1-2% variation. Running real nice on low throttle.
For the boosted car, I think 10% variation is way too much. Again - I tune it to 1-2% variance. But you need to be able to measure it accurately. Collect enough fuel and have a decent way to measure it.
I have since started altering this tuning via the park plug colours. But 1-2% variance was my start point. I have exchanged the black soot colour on the plugs for a dark tan colour.
Alan