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First, I prepped the car and put it in full "track mode"..
Got to the track, let the car cool down, got the lanes and let it rip. The air was averaging +380' DA and very humid, lots of water vapor.
First pass was 10.63@128.85 with a 1.54 60'. So cooled the car down, decided to make a jet change, made another pass and it slowed some to a 10.65@128.84. 1.54 60'. We decided to wait it out, let the car cool down and hope for better air as the night went on, but it actually warmed up some, so I tried it again, left at idle, shifted a little lower in the rpms, and it went 10.59@128.76, 1.52' 60'.
A little disappointed, I was really hoping for a 130 mph trap. After looking at the datalogs, it appears to have leaned out in 2nd gear to 14.0 afr on all 3 passes for some reason, its never done this before, and it doesn't do it on the street, so I am thinking its a turbulent air flow thing or something without the air cleaner on it. Explains why my 1/8 mph was 1 mph slower then it should be.
Anyway, here is some vids and more pics:
Courtesy of John Woods, Houston Raceway Park media guy and CF forum member
You can see the car was not happy in 2nd gear by the lean and erratic afr. Gonna have to research this more, it doesn't do it on the street with the air filter on it.
My drive home, you could say its a little humid...
Great job collecting and sharing all the data, Alan. It looks and sounds great. Do you think you'll find better air before the heat comes, or is this too close to spring to hope for that? You're close to your goal! Could you possibly gain by putting the filter element on? In any case, it's a strong effort for the first time out. I suspect that you'll sort out the AFR and get back out there soon.
Great job collecting and sharing all the data, Alan. It looks and sounds great. Do you think you'll find better air before the heat comes, or is this too close to spring to hope for that? You're close to your goal! Could you possibly gain by putting the filter element on? In any case, it's a strong effort for the first time out. I suspect that you'll sort out the AFR and get back out there soon.
Les, I’m watching the weather for next Friday, I’m keeping the car in race trim until then. If the weather is exceptional, I’ll run it again. I will try a pass with the air cleaner on it. My AFR on the street is smooth and steady so it’s gotta be something with the filter. Usually just the air cleaner base is the fastest way to go but...not sure now. If I don’t get to run it next friday, that’s it for me. I start working weekends in April usually, the air is not as good. Plus I change a lot of stuff on the car to get it track ready, and I’m ready to get it back to normal ASAP.
In this situation, it kind of is what it is I guess. Coulda, shoulda, woulda.....��
Airflow can be a funny thing. One of the air cleaner designs I worked on would flow huge amounts of air with the element in, but would get extremely turbulent without the element and flow very little air. Under the hood with air coming in through the radiator and from underneath the car, it's hard to say what it looks like around the carb entry. Elements straighten the airflow and make it more laminar. If there is enough surface area to the element, you could very well flow more air with it in place, certainly smoother more laminar air.
Airflow can be a funny thing. One of the air cleaner designs I worked on would flow huge amounts of air with the element in, but would get extremely turbulent without the element and flow very little air. Under the hood with air coming in through the radiator and from underneath the car, it's hard to say what it looks like around the carb entry. Elements straighten the airflow and make it more laminar. If there is enough surface are to the element, you could very well flow more air with it in place, certainly smoother more laminar air.
Mike
I agree, and believe you are right. I have a datalog from a street pass with the air cleaner on and the AFR is straight as an arrow all through 2nd and 3rd gear..... Where as last night the AFR went erratic in 2nd. Its weird, if its turbulent air, you would think it would be worse in 3rd with more wind coming into the engine compartment. Next week I'll try the air cleaner on at the track. I have a K&N 14x4", I've made a pass with it before and if I recall, it trapped the same mph, but didn't 60' as well ironically. Its worth a try I guess.
Airflow can be a funny thing. One of the air cleaner designs I worked on would flow huge amounts of air with the element in, but would get extremely turbulent without the element and flow very little air. Under the hood with air coming in through the radiator and from underneath the car, it's hard to say what it looks like around the carb entry. Elements straighten the airflow and make it more laminar. If there is enough surface are to the element, you could very well flow more air with it in place, certainly smoother more laminar air.
Mike
Here is a datalog from a street hit a couple weeks ago.... Notice how smooth the AFR is from 2nd on...(the purple line)
Here is a blown up shot of the last pass last night...looking at the purple trend, you can see it got real unhappy in 2nd gear, lots of that was over 14.0 afr... I think the air cleaner is the resolution for this...I hope...LOL
Fuel pressure was a steady 7 psi through the whole pass so, I know its not that.
Alan - Nice vids, and the car looks great. So you matched your previous best ET while running 1 full mph better. I know you changed the camshaft while you had the motor out, and you dynod the engine and you picked up some power compared to before, but not a huge gain. How does your short time on this run compare to that on your 10.59 at 127 pass originally? You might have moved your torque and HP curves up in your rpm range a little compared to before. Anyway, I know you were hoping for more, but really that car is amazing. A mid 10 second, all motor, C3 that you can drive, and have driven, cross country, is very impressive.
Alan - Nice vids, and the car looks great. So you matched your previous best ET while running 1 full mph better. I know you changed the camshaft while you had the motor out, and you dynod the engine and you picked up some power compared to before, but not a huge gain. How does your short time on this run compare to that on your 10.59 at 127 pass originally? You might have moved your torque and HP curves up in your rpm range a little compared to before. Anyway, I know you were hoping for more, but really that car is amazing. A mid 10 second, all motor, C3 that you can drive, and have driven, cross country, is very impressive.
Bruce, on my old previous best from 6 years ago, the car went 10.59@127.52, 1.51 60' in -850 DA...(I looked at the old slip this morning). At that time the car was 3660lbs.. Best 60' ever was that 1.51.
Last night it went 10.59@128.76, 1.52 60', in +380' DA, at an unconfirmed 3700lbs estimate... The engine on the dyno gained 35 CORRECTED HP.....and about 20 OBSERVED HP. So yeah, I was definitely hoping for 2-3 mph gain, but, I guess if you look at the DA swing, additional 40lbs and a minor lean out in 2nd gear....I think I could see not getting the full amount of that 35hp gain to the slip..... Flip side of that thinking is, it made and actual 20 more HP, and that jives with the 1 mph gain in worse air. Its really splitting hairs but...that's how I get when chasing numbers.
Either way, the car runs/drives great, sounds killer, revs higher and the power holds on longer, no more hyd roller lifter clatter etc etc... so even if I didn't gain much power, the other improvements help justify the cost of the rebuild. Plus its all fresh looking under the hood to match the body's new paint....
Comparing last night to your previous best, you picked up a full mph in air that was worse by a DA difference of 1,200. That shows a significant improvement in my book. If you can get back out in -850 air, you'll get that 130mph.
Great videos and data! Glad to see you are going back out to the track after you address you potential issues. I know a lot of guys who just accept disappointing results and never get them resolved. Didn't you make a converter change? Anyway, looking forward to your next time out.
Bruce, on my old previous best from 6 years ago, the car went 10.59@127.52, 1.51 60' in -850 DA...(I looked at the old slip this morning). At that time the car was 3660lbs.. Best 60' ever was that 1.51.
Last night it went 10.59@128.76, 1.52 60', in +380' DA, at an unconfirmed 3700lbs estimate... The engine on the dyno gained 35 CORRECTED HP.....and about 20 OBSERVED HP. So yeah, I was definitely hoping for 2-3 mph gain, but, I guess if you look at the DA swing, additional 40lbs and a minor lean out in 2nd gear....I think I could see not getting the full amount of that 35hp gain to the slip..... Flip side of that thinking is, it made and actual 20 more HP, and that jives with the 1 mph gain in worse air. Its really splitting hairs but...that's how I get when chasing numbers.
Either way, the car runs/drives great, sounds killer, revs higher and the power holds on longer, no more hyd roller lifter clatter etc etc... so even if I didn't gain much power, the other improvements help justify the cost of the rebuild. Plus its all fresh looking under the hood to match the body's new paint....
So it is what it is....
Please pardon the sidetrack, but can you go into a little more detail on that issue? (Just a fellow BB user interested in any pertinent experience/advice.)
Comparing last night to your previous best, you picked up a full mph in air that was worse by a DA difference of 1,200. That shows a significant improvement in my book. If you can get back out in -850 air, you'll get that 130mph.
. Thanks Bruce, that is my thought as well, at least that’s what I’m hoping for.
Originally Posted by 632C2
Great videos and data! Glad to see you are going back out to the track after you address you potential issues. I know a lot of guys who just accept disappointing results and never get them resolved. Didn't you make a converter change? Anyway, looking forward to your next time out.
Thanks Steve. No converter change. All we did was re-ring/bearing the motor, a little more head work/new valves and a slight increase in cam, but did switch to solid roller lifters. (Hyd roller cam w/solid roller lifters). It gained 35hp on the engine dyno.
03-02-2019, 11:55 AM
Went to the track last night....
...and thanks for the vids.
