QF SS 830 Tuning Help LQ9/243 ASA
07-26-2013, 08:40 AM
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QF SS 830 Tuning Help LQ9/243 ASA Fixed the electrical gremlins now I need some help with the Carb. Im a carb newbie and Im basically reading my *** of trying to understand how they function etc to better educate myself. But have come up empty with how to go any further. AFR readings best as I can see as Im trying to glance at them while at the laptop and road.
Motor Specs:
LQ9 w/243 Heads, ASA CAM, LS6 Springs, 1-7/8 LT's, 3" Y to 3.75" Single (240sx) no cats, Spectre Dual Plenum. AEM Wideband, 6010 BOX ALL BRAND NEW.
TIMING CURVE:
13 at 0
22 at 500
31 at 2000 to 5500
27 at 5500 to REDLINE
MAP is 10 until 7, then drops to zero
First Drive:
1. Right out of the box I slapped the QF on set mallory FPR to 6.5.
2. Fuel level was above sight glass on carb.
3. AFR was in the 10-11 range at idle.
4. AFR at cruise/WOT pegged at 10 on the gauge or any LOAD.
Burned little over 1/4 tank of gas in 27 miles plus idling in garage.
Drove ok I guess, rich as hell, a little hesitation on pedal etc.
Second Drive
Set the Mallory FPR at 0 psi and slowly brought fuel pressure up to fuel level in middle of sight glass per QF which was 5-5.5 psi.
2. Adjusted IDLE 4 corners to get AFR at 14-14.7.
3. Tried to adjust idle speed down but cant go below 1100.
4. Readjusted IDLE conrners to 13.5 and can get IDLE down to 1050.
5. WOT AFR was around 10.9ish
No hesitation, it appeared that when crusing AFR's were around 11.5-13ish
When I punched it, within reason since still breaking in, it went no bogging etc. It would also lean out if I let go of the gas and coasted in gear which I would think is normal? AFR gauge was much more responsive this time around.
Id like to get the IDLE down some more to around 850-950. According to the carb sheet from QF the carb has the following:
Primary J: 78 PRI Nozzle: 33
Sec Jet: 86 Sec Nozzle: 35
IDLE AIR B: 70/70 Needle/Seat: 120
HS Bleed: 28/28 PV: 6.5
Any help is appreciated! Also how much effort is required to loosen the float adjusters. They take a slotted screwdriver and I cant break them loose for nothing without the potential to strip the slot.
Motor Specs:
LQ9 w/243 Heads, ASA CAM, LS6 Springs, 1-7/8 LT's, 3" Y to 3.75" Single (240sx) no cats, Spectre Dual Plenum. AEM Wideband, 6010 BOX ALL BRAND NEW.
TIMING CURVE:
13 at 0
22 at 500
31 at 2000 to 5500
27 at 5500 to REDLINE
MAP is 10 until 7, then drops to zero
First Drive:
1. Right out of the box I slapped the QF on set mallory FPR to 6.5.
2. Fuel level was above sight glass on carb.
3. AFR was in the 10-11 range at idle.
4. AFR at cruise/WOT pegged at 10 on the gauge or any LOAD.
Burned little over 1/4 tank of gas in 27 miles plus idling in garage.
Drove ok I guess, rich as hell, a little hesitation on pedal etc.
Second Drive
Set the Mallory FPR at 0 psi and slowly brought fuel pressure up to fuel level in middle of sight glass per QF which was 5-5.5 psi.
2. Adjusted IDLE 4 corners to get AFR at 14-14.7.
3. Tried to adjust idle speed down but cant go below 1100.
4. Readjusted IDLE conrners to 13.5 and can get IDLE down to 1050.
5. WOT AFR was around 10.9ish
No hesitation, it appeared that when crusing AFR's were around 11.5-13ish
When I punched it, within reason since still breaking in, it went no bogging etc. It would also lean out if I let go of the gas and coasted in gear which I would think is normal? AFR gauge was much more responsive this time around.
Id like to get the IDLE down some more to around 850-950. According to the carb sheet from QF the carb has the following:
Primary J: 78 PRI Nozzle: 33
Sec Jet: 86 Sec Nozzle: 35
IDLE AIR B: 70/70 Needle/Seat: 120
HS Bleed: 28/28 PV: 6.5
Any help is appreciated! Also how much effort is required to loosen the float adjusters. They take a slotted screwdriver and I cant break them loose for nothing without the potential to strip the slot.
07-26-2013, 11:14 AM
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What is your vacuum at idle? To start things off you should check vacuum at idle and divide in half. This will tell you what power valve to run. Mine idled like crap , and I had to put a 2.5 in it. Now it idles much better. Not sure if this will help, but its worth a step.
07-27-2013, 09:02 AM
#4
You're running awfully rich at idle at WOT. I wouldthink you could do better. Uou have some tuning to do
Idle timing affects idle speed. I had the same problem, had the idle speed screws backed out to the stops and still had 1100RPM. The beauty of the Msd box is you can put a super lownumber in at 500 rpm and still have it jump back up to normal by 1000 rpm.
I ended up setting the idle speed screws so there was 20 thou of the transfer slot visible primary and secondary then used the idletiming to set idle speed. Car had a slight hesitation with slight throttle movements until I got that fixed.
Idle timing affects idle speed. I had the same problem, had the idle speed screws backed out to the stops and still had 1100RPM. The beauty of the Msd box is you can put a super lownumber in at 500 rpm and still have it jump back up to normal by 1000 rpm.
I ended up setting the idle speed screws so there was 20 thou of the transfer slot visible primary and secondary then used the idletiming to set idle speed. Car had a slight hesitation with slight throttle movements until I got that fixed.
07-30-2013, 01:54 PM
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Drove the car for a good while this weekend. Still rich all around but no bogging or gestation etc. Terrible gas mileage but no black smoke or dieseling. Getting about 7-8 mpg at the moment but man it was fun just to drive it around.
Started looking into jetting etc and spoke with quick fuel today. After explaining to them the situation they recommended dropping down two jet sizes on the primary and secondary and adjusting the secondaries at idle as we determined I only backed down the primaries. No need to mess with air bleed according to them because I can get the afr at idle to lean out etc. Now I just gotta wait for new jets to get here.
Started looking into jetting etc and spoke with quick fuel today. After explaining to them the situation they recommended dropping down two jet sizes on the primary and secondary and adjusting the secondaries at idle as we determined I only backed down the primaries. No need to mess with air bleed according to them because I can get the afr at idle to lean out etc. Now I just gotta wait for new jets to get here.
08-02-2013, 06:13 PM
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Yep I have the PCV from driver valve cover to bottom of carb and and a filter on breather on the passenger side. Intake is a spectre low profile dual plenum because its the only thing that would fit under my hood that already had a 3" cowl.
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08-03-2013, 06:52 AM
#9
He is talking about a cold air intake. I hope the dual inlet low profile moves more air that the single I have. If the actual inlet is the same size/profile as mine ,Im afraid it wont do any better. It wont move enough air for the OPs engine. I blew 300 bucks on mine and it chocked my engine down at 5200ish RPMs. I went from 12.42 to 12.15 in the quarter by pulling the spectre and slapping a 14" breather on mine. That isn't a true indicator of the difference because my torque converter was going south on the 12.15 run.
To the OP, go to spectre's chat forum and ask how many cfms the dual low profile will support. The single would only handle 625 cfm, you will need somewhere around 1000cfm to avoid a restriction.
To the OP, go to spectre's chat forum and ask how many cfms the dual low profile will support. The single would only handle 625 cfm, you will need somewhere around 1000cfm to avoid a restriction.
08-03-2013, 07:37 AM
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He is talking about a cold air intake. I hope the dual inlet low profile moves more air that the single I have. If the actual inlet is the same size/profile as mine ,Im afraid it wont do any better. It wont move enough air for the OPs engine. I blew 300 bucks on mine and it chocked my engine down at 5200ish RPMs. I went from 12.42 to 12.15 in the quarter by pulling the spectre and slapping a 14" breather on mine. That isn't a true indicator of the difference because my torque converter was going south on the 12.15 run.
To the OP, go to spectre's chat forum and ask how many cfms the dual low profile will support. The single would only handle 625 cfm, you will need somewhere around 1000cfm to avoid a restriction.
To the OP, go to spectre's chat forum and ask how many cfms the dual low profile will support. The single would only handle 625 cfm, you will need somewhere around 1000cfm to avoid a restriction.
08-03-2013, 03:03 PM
#11
Looking at your intake, I can't see where the ignition module mounting holes are plugged on your intake. I may be wrong because the picture is low resolution.
If they are not plugged that may be a vacuum leak which would contribute to your high idle as one of the holes is a through hole into the intake port.
If they are not plugged that may be a vacuum leak which would contribute to your high idle as one of the holes is a through hole into the intake port.
08-19-2013, 06:53 AM
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Update: swapped the primary and secondary jets down to 76 and 84. Adjusted the secondary idle screw and was able to get ~920ish rpm at ~14.0 afr during idle and was stable. During full throttle runs afr's are about 11.6-12.1 so that has improved. While cruising, if I can hold the throttle correctly to maintain the speed, afr's seem to hold at ~13.5-13.9.Response is fine, no hesitation, no bogging etc, and gas mileage has increased substantially. Last go around I got 80ish miles to a 13 gallon tank this weekend we put 120 miles on it and haven't gone past 1/2 tank yet. Gonna ride this setup out for a little bit and continue to monitor how it drives etc.
Finally took the family out for a drive and my 3 year old was so thrilled to finally be able to drive in daddy's car.
Finally took the family out for a drive and my 3 year old was so thrilled to finally be able to drive in daddy's car.
08-19-2013, 09:37 AM
#15
Gotta love the first ride with the family. My kids have gone out with me but the wife still won't come near the car.
Sounds like you are getting closer on the tuning. Still seems awfully rich to me. I would drop at least another 2 jet sizes, get the WOT AFR right and I'll bet your cruise numbers will clean up with the same change.
I think what hurts with air boxes like yours is the transition into the carb. Sort of a hard right turn. Bigger tubes won't help that much. I wonder if a GMPP single plane intake would give you enough clearance to run a 1" drop base air cleaner. The single plane might be a better match for your cam and heads too. But that is a different motor and different discussion.
Sounds like you are getting closer on the tuning. Still seems awfully rich to me. I would drop at least another 2 jet sizes, get the WOT AFR right and I'll bet your cruise numbers will clean up with the same change.
I think what hurts with air boxes like yours is the transition into the carb. Sort of a hard right turn. Bigger tubes won't help that much. I wonder if a GMPP single plane intake would give you enough clearance to run a 1" drop base air cleaner. The single plane might be a better match for your cam and heads too. But that is a different motor and different discussion.
