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Keep everyone up to date with how your project is coming along.
My name is Dawson Boys, I feel most of the information in these videos is for a different application than mine. So I would like to make this thread to answer a few questions and have some discussions.
I race a 1988 F150 with a 557 CI BBF. It has a Holley Dominator 4500 Carb and we run Q-16.
Can anyone help me out a little more with fuel since we always run less than 300 feet I am not sure how much fuel it actually needs. Am I leaving power on the table?
Secondly I would like a little more help with suspension set up if anyone has experience in setting up a truck for conditions that change every single pass. And I only have a few hundred feet to get it right.
SIU-Carbondale Finance Student
Driver for Dirty Boys Racing
Super cool Truck Dawson Q16 is magical i generally tune this kind of combo to around .85 lambda i don't use afr to measure q16 as most after market gauges are set to read stoich of 14.7 which is incorrect for q16 its stoich is 13.5 so this will throw out your readings massively
i hope this helps sorry im not a suspension guy for what you are doing
NOTE, discussion/thoughts - NOT gospel!
Second point first - I assume this is pulling, or maybe dirt/mud drags?
If pulling, there will probably be a specified height range and you'll be best with the truck hitch slightly higher than the sled, to minimise lifting at the rear. With pulling you may be best to run more nose weight, if legal, to maximise overall bite and avoid front lift - might be a problem with front end strength, though, especially the steering.Lower ride height 'should' help.
With dirt/mud drags, my guess is the fronts will be more for cleaning the ruts for the rears to get into firmer ground for grip, so a more even load with maybe a rear bias? - but not my thing, so could be quite wrong.
First question. Is there are reason you think you may be under, or over, fuelling the vehicle? As you say, conditions change each run so you can't compare times, so you will need somthing that tells you what you have and what affect changes have - a lambda on each exhaust will tell you what you are actually dealing with. If you're not running one, at least one knock sensor would be a good idea - certainly cheaper than a strip down and parts replacement.
That is a big engine, but they can be built in a range of configurations of torque/power and rpm - depending on the full spec' of the engine and it's actual use - the 4500 may be too big or too small, IIRC, they run from 950 to 1475 CFM?
If you can, I'd suggest taking the truck to a reputable cab' specialist and have it run on the rollers/dyno - carbies can be tricky to set up, as there are several different fuelling stratagies used through the airflow and throttle range, you may get some right but be compromised in other ways. It also allows you to get the timing curves, etc, correct as that can also mean a lot of power being left on the table.
Heck, with that airflow demand, even the air filtration could cost significant power if not done right.
We are Mud Drag Racing.
We run a 1250 Dominator.
Nothing I have would lead me to believe the truck is over fueled or under fueled. I do not really have a way to check this information.
One of my Crew Members bought an O2 sensor but we have not yet installed it. So what I am gathering is both of you are advising that I need to install this in order to be able to make the best tuning decisions.
We are also going to install a cowl hood this winter because we to believe the additional air flow would help much like the air filtration point you brought up.
My Crew Chief is very old school and it is up to me to try and bring these new ideas to the team. So thank you all for the assistance and help with this new endeavor I am undertaking.
I also plan to change to a 90/10 front shock and then see how it acts and start messing with the rear shocks from there.
I would really like to get it put on a dyno as well but I have not allocated the funds for this yet.
Thank you all for the help and my ignorance of this topic.
Haha, being 'old school' might be an advantage - many younger guys have never seen, let alone worked on, a carbie.