BLWUR AFR tweaking

[krasuskyp]

I've finally got my car setup the way I've want it, and now want to really hone my AFR's in and need some help from the braintrust here (even Ronknees!).

quick build stats:

- '87 stock 3.3L
- SC cams
- Garrett / ITS 0.82
- Bell full-bay IC w/ TiAL BPV vent to atm
- BLWUR
- dual 044s relayed
- MSD 6AL-2 / blaster coil
- BMP filter on metering plate
- Powerhaus headers
- Zork
- GReddy Profec B Spec II EBC @ 0.95bar
- VEMS AFR gauge

So my car like every CIS 930 has always run out of fuel past 5k, 12.8-13.4 - so I'd typically not loiter up there long and upshift quick / earlyish. I'd borrowed some CIS gauges awhile back and all pressures looked great, and installed a new pressure regulator / shims.

Now with all my mods, it's the same damn story - and after the recent switch to full-bay IC it seems I may even be running out of fuel earlier now - like 12.6 and worsening starting @ 4,500 now.

Here's my current AFR's:

- idle: previously 10.4, new mods found it @ 10.2 (which I believe is where the gauge may even "bottom out"?)... just bumped it to 11.4
- off throttle cruise: 13.5-14
- decel : 14-14.5
- WOT: 10.2 until revs build near 4k, then rapidly rise to 12.4-13.4

I know I need to pull out the bottom disc of the BLWUR, and need to RTFM to discern how exactly to do such (any pointers appreciated!), and I finally scored some CIS gauges last winter that I'm itchin to use.

Seeing what you see above... any thoughts as to where I should begin?

From what I've read here and know, I feel all my #'s are pretty damn good... except at !@#$%^&* WOT. Fuch.

The car runs like a fookin banshee, and idles great without hunting or loading up / fouling (even @ 10.2 lol, tho a little hunting).

Oddly enough, whereas I used to get nominal flames with my previous setup (Garretson / Rarly dual-out hooligan / 3LDZ), now I get none - fut the wuck???

Only running nits I have now if any are:

- trying to throttle modulate in higher RPMs with any boost built causes some lurch / surge when lightly lifting
- very slight 'miss' in 4th gear part throttle / transition throttle... AFR is @ 10.2 during this, almost seems like cap may be fouled again (newerishish?) or maybe I need more timing (forget where we set it roadside enroute to der 'palooza '09... Jake you recall lol?)?

I'm looking forward to nailing this, as I know I'm leaving some performance / drivability / FLAMES on the table.

Looking forward to this final tweak and to then being able to hold upshifts in longer / higher revs, and to adding maybe another 0.05bar

TIA, gents!

[RarlyL8]

You should be able to adjust the boost pressure on the WUR and then nudge the WCP and idle mixture where you want it. Is the adjustment not working?

[krasuskyp]

Thanks Brian - I installed the BLWUR how it was sent to me (I think I got it from you even lol) so that's how it is still set up.

So, to enrichen the boost pressure, I pull out the bottom disc correct? I know, I need to RTFM! 8-)

But, my concern is I'm @ 10.2 right now under boost, and THEN crap toward 5k RPM - will enrichening that setting just worsen that? Isn't that why some folks install an RPM switch?

And then move on to the other two settings?

[gsxrken]

Paul that's a real nice list of parts you have there. I can't comment on the BLWUR settings but I also can't refrain from chiming in on your 10-something idle. My car idles around 13.7-13.9... I would think 10-ish would be eye-watering " get that smelly thing out of my house" rich.

Is that where it wants to be after trial and error, or have you not tried adjusting it yet?

[smurfbus]

I'm at 14.5 idle and 15 at cruise. I just could not get the WOT AFRs where I wanted without extra electonical gadgets (AIC-1). It would always get lean after 5000rpms what ever I did with the adjustments.

Where is your system pressure now? Time to start using the CIS meter! I found out that my fueling was at its best at around 6bar system pressure.

[Ronnie's.930]

First things first, Paul, it will be necessary for you to grow a pair (that's asking a lot, I know)!

2nd - do you have this thar tool (not long lost to one of yer several orifices) for drawing the disk out (thus lowering full-throttle-enrichment, control pressure)?





3rd - I would suggest checking one "thing" and making only one adjustment at a time. For example, since you are going lean at high rpm (full throttle enrichment), if would be smart to start by drawing the bottom side disk out about 2mm, go for a drive and observe AFR at high RPM . . . don't be too concerned about AFRs at other RPMs for the time being (well, except yer redonkulously rich idle AFR that is - ya' beech). If still too lean, and there is room left to move the disc even farther out (not already level with the housing, in other words), move it another mm or so and re-test to see if you are able to adjust it rich enough.

[dos531]

Sounds like you're a perfect candidate for the RPM switch. I don't think you're going to get your ratios where you want them without it. As you said, you can lower the warm pressure which will help up top, but will make it way too rich down low.

[T77911S]

with a good turbo, header and zork i think you have reduced the back pressure so much the CIS cant put out enough fuel to keep up.

EFI

[RarlyL8]

Paul do you have the instruction booklet? There is a sheet that lists the baseline parameters.
Your idle mixture is way off and does not correspond to the cruise mixture. Several things can cause that such as an aging fuel head or exhaust leak. If that is the case the ARF readings are faulty. Check and record the fuel pressures cold, warm, and boost (using an air compressor). Once the WCP is back in spec we can look at the boost CP and see if you're being choked by the fuel distributor settings.

[Tippy]

Damn! 10's at idle. She's pig rich. I have noticed my engine loves 12's but that's due to EFI and only firing the injectors once a crank revolution.

If it were CIS, you should be able to run leaner due to having fuel at every cylinder at all times.

[krasuskyp]

thanks guys

yes B I have the BLWUR instructions... and the corresponding tool too (I think!) - like I said, need to find them and read it

doubting I've got an exhaust leak - just a vband'd Zork lol

and I'm hoping my fuel head's OK - only 63k miles, always 93 octane and occasional STP Techron, and never "just sits" (cringe - oh the horror!!!)

I thought I recalled a number of folks here idling in mid/high 10s (lololol Kenny... jahmon, nail / head with yer Nostrodomus'd editorial commentary - that, and "you smell like CAR!")? What would you all suggest I idle at then with this setup?

and

is it best to establish idle AFR before moving to the WUR tests / tweaks?

how do you test boost pressure w/ the compressor? (sorry for mah ignerunce)

^this^ is the stuff I came here to seek... the process - the actual adjustments I can find in the BLWUR book

[gumba]

"So my car like every CIS 930 has always run out of fuel past 5k, 12.8-13.4"

Paul, I would try and borrow another wur and see if the results are the same. There could be something else going on as Rarlyl8 suggested.

I looked at the dyno runs from the Jerry Woods build on my 3.5, SC cams, twin plug, full bay i/c, ssi's, dp muffler (empty can), cis, stock fuel, stock wur. 380 h.p. @5500 rpm @.9bar. The a/f's were 11:1 from 3000 rpm - 4500rpm, 11.5 @5500rpm, 12:1 5500 - 6500 rpm. We were living in CA. at the time, so all the smog gear was in place & working.

For the past few months my a/f's were all over the place except at wot. I checked for leaks, had a shop play with the cis, swapped out the wur with a fresh one from RarlyL8, no difference. Then I tightened all the intake bolts, cleared right up. The motor was built in '07.

[JFairman]

The only way you'll ever get enough fuel at high rpms with your setup using a ball bearing Garrett turbo will be with a CIS Flowtech - Rebuilding Bosch Fuel Distributors & Warm-Up Regulators fully modified fuel head.
Lowering control pressure alone with a stock lambda fuel head and your Garrett won't do it.

A cast iron black euro fuel head will give you 10% more fuel up top and the aluminum lambda fuel head with internal machining done by Larry at Flowtech will give you 20% or more up top.
The modified fuel head will richen up the midrange too and an rpm switch and solenoid valve blocking the boost line to the control pressure regulator below somewhere around 4400 rpms will control that.

Maybe your ball bearing Garrett turbo spools up fast enough to blow in enough air to go with the rich CIS midrange AFR's

[krasuskyp]

thanks Harold - BLWUR was new a couple of years ago... I'd think it'd still be fine?

did tighten intake nuts years back, but good suggestion - will check them

thanks Jim - any idea how much Larry gets for the FD work?

btw, journal not ball bearing turbo 8-)

[JFairman]

"any idea how much Larry gets for the FD work?"
Best to call him and ask.

"btw, journal not ball bearing turbo 8-)"
oh.. sorry to hear that. guess you'll need the rpm switch doo dads.

[RarlyL8]

I work with Larry on many things and am a distributor for the Bosch rebuilds. We also handle modifications. I keep all these items in stock including the modified 007 Fuel Distributor.
Before mucking up the works with a new fuel distributor you need to get your system tuned the way it is and only then will know how much, if any, extra fuel is needed up top.

[Ronnie's.930]

Originally Posted by krasuskyp

I thought I recalled a number of folks here idling in mid/high 10s (lololol Kenny... jahmon, nail / head with yer Nostrodomus'd editorial commentary - that, and "you smell like CAR!")? What would you all suggest I idle at then with this setup?

Paula, with the Lambda system functioning, the engine is forced to idle at 14.5 +/- .2; idles just fine that way, but is on the verge of lean misfiring. And without the Lambda system functioning, most folks here report that 13-13.5 +/- .2 is the sweet spot.

PS- Brian is correct, your idle afr is so "off", and does not correspond to you cruise afr, so it makes more sense to set those up first (prior to adjusting the WFO enrichment), rather than what I recommended before.

FU, btw!

[T77911S]

Originally Posted by RarlyL8

I work with Larry on many things and am a distributor for the Bosch rebuilds. We also handle modifications. I keep all these items in stock including the modified 007 Fuel Distributor.
Before mucking up the works with a new fuel distributor you need to get your system tuned the way it is and only then will know how much, if any, extra fuel is needed up top.

set your CP to spec and set your idle mixture and see how much and where you need more fuel.
then contact larry. the rebuild is around $500 i think, it depends on what else he does to it. but if you let him know whats going on he can help.
great guy to deal with.
he will want your WUR too so he can adjust the boost CP

[RarlyL8]

Your WUR is adjustable, there is nothing for Larry to do with it and he is not a fan of the manually adjustable units. BL and I set these up based on information given about the engine and expected output. When you find your instruction pamphlet you will find the baseline parameters that the WUR was set for. These parameters were specific for your fuel distributor and system pressure. I spent a lot of time with both Larry and Brian Leask coordinating the building of systems instead of individual components. It is necessary that you return to the set specs so we can see what is going on. It is also critical that your diagnostic instruments are properly calibrated (AFR, fuel pressure gage, boost gage). I'll be glad to help you once you have found the instructions and familiarized yourself with the procedures.

[911nut]

I have a stock 3.3 L engine, BL wur, SC cams, 965 i/c and baby K29 turbo and my afr's range from 11.0 to 12.5 at 6000 rpm. My boost control pressure is .2 bar lower than stock. I think with a day's worth of tuning you can get your afr's into the box with the components that you have.