Tuning for WOT

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MomsDuster

MomsDuster

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Ok guys, got my idle, cruise, transition and PV tune really good and smooth. She’s running awesome. Started playing with WOT. Using my Dragy to see approximate 1/4 times and Mph. Here are a couple screen shots.
The 13.04 @ 106.56 was a few weeks back with #80 jets in the secondaries.

The 13:13 @ 104.67 was this morning with #84 jets.
Seeing that my 60’ sucks, but they are real close and the 330’ is close and even a couple hundredths better. Then everything starts tapering off from there. Can I therefore assume that I’m loosing efficiency from the #84 jets? And I should probably lean it out a smidge until best mph comes back. At some point I know for best ET I’ll have to address the 60’.

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Jets for MPH and pump cams & squirters for 60' & 330'. But you'll have to go back & forth to fine tune it. Ideally you want the squirters to stop squirting simultaneously when the primary jets kick in (on a double pumper). I also found a little benefit to jet the deeper side of the plenum on a dual plane a couple of jets bigger than the shallow side. But I don't know if it varies between different dual plane intakes.

Try to do tests on the same day because traction needs to be consistent as well as weather conditions, including breezes!
 
That's a big drop in mph. As long as conditions were fairly close, i'd get my hands on some 82's to see what that does with the mph.

At this point, your just trying to see where your making the most power, but you'll eventually need to work on the efficiency down low...60fts.
 
Why is the 60’ so slow? That’s way off for a low 13 vehicle. I’d look for improvement there. It will affect everything down track.

Is the car spinning off the line? That changes the finish line MPH you know.
 
413 said:
Why is the 60’ so slow? That’s way off for a low 13 vehicle. I’d look for improvement there. It will affect everything down track.

Is the car spinning off the line? That changes the finish line MPH you know.
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Yeah, she’s a spinning. I have to roll into it off the line. I’ve gotten it down in the 2.20’s pretty constantly. If I get too far into the converter and nail it off the line it’s just a freaking smoke show.
 
Spinning like that? Well than you can forget tuning by the finish line MPH. It’s going to be different every run anyway.
 
MomsDuster said:
Yeah, she’s a spinning. I have to roll into it off the line. I’ve gotten it down in the 2.20’s pretty constantly. If I get too far into the converter and nail it off the line it’s just a freaking smoke show.
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When they're on concrete sticky with race tire cmpound from other cars, there will be somewhat better traction.

Only one run so there may be a little more there. Firestone's with traction prob about the same as the Cooper's. Not really footbraking in the sense of loading the converter. Just rolling into the throttle from maybe 1000 rpm. Leave on the last green.
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Other factors include the 'anti-squat' in the suspension.
 
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12.50 et mph in a 15.50 chassis... :lol:

target 60's should be 1.75's area

definitely go back on jetting. put 82's in an see what happens. then go 78's

fun part of tuning it up.
 
FOR TUNING ONLY.
Add a couple hundred pounds in the trunk.
Get the tire to stick and then work from there.
 
Try loading the converter more. I know it seems counterintuitive, but it doesn’t let the motor get so much of a running start at the converter. If I’m on a hero sticky track, I lower my launch rpm. Get a hair more flash rpm. I have a relatively tight converter 3300 rpm flash because of the small tire.
 
furrystump said:
Try loading the converter more. I know it seems counterintuitive, but it doesn’t let the motor get so much of a running start at the converter. If I’m on a hero sticky track, I lower my launch rpm. Get a hair more flash rpm. I have a relatively tight converter 3300 rpm flash because of the small tire.
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Please advise; if your brakes will not hold the car still much past 2100 rpm (in the driveway), your TC flashes @ around 3800, and your peak power is around 5400, are you sayin' I should try to get the brakes to hold better rather than rely on the TC to get me to the right spot at the light?
 
Just like the other guys are basically saying ! Until you get you suspension problems fixed , your going to be chasing your tale !
 
like_A_pike said:
Please advise; if your brakes will not hold the car still much past 2100 rpm (in the driveway), your TC flashes @ around 3800, and your peak power is around 5400, are you sayin' I should try to get the brakes to hold better rather than rely on the TC to get me to the right spot at the light?
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I've never had a converter that would break loose at 2,100 and flash any higher then about 25/2600.
 
So the car wont sit still past 2100 with the brakes applied in my driveway and while I apply more and more gas.
OldmanRick said:
I've never had a converter that would break loose at 2,100 and flash any higher then about 25/2600.
Click to expand...

So help me understand exactly what flash and stall means in the context of a torque converter. The dynamic 9.5 claims that it stalls above 3800. when I hit the gas from a stand still, the tach tops out between 3500 and 4000, I assume thats "flash".

2100 rpms is about where the car starts to move as I gently add more gas. Thats in the driveway with street tires. I have assumed these are two different issues. I think that I'd like to launch at higher rpms to reduce that 60' time.
 
I assumed the car would break the tires loose just after 2100. You say your flash is close to 4k, so if the car just wants to move above 2k, that's not a issue as far as i'm concerned. Just bring the engine above idle at the line...1200/1500 ish, and let it eat.
 
So, the brakes holding the car is a “separate” issue. There is a subtle difference between stall rpm and flash rpm. Stall rpm is the rpm the engine will rev to if the driveline is locked and your foot is on the floor. Your car won’t allow that because the brakes won’t hold. You shouldn’t do that anyways. You can break things and it creates incredible heat, incredibly quickly. Flash rpm is the rpm the engine revs to before it starts to move with your foot on the floor. Say your flash rpm is (I’m completely making this number up) 3500 rpm. That number might be higher if you don’t load the converter as you launch. Say just off idle. You can slightly increase the flash rpm by giving the engine a running start at the “normal” flash rpm. If you load it to say 3400 rpm, the engine doesn’t have the extra momentum approaching the 3500 rpm. These are not big differences, but if I launch off idle I will knock the tire off. Launch at 2700-2900 rpm and it will hook and go.
 
appreciate that ^^^. I will explore the brakes (adjusters particularly) and try higher rpms at the track with slicks to see if I can get it to stay on the line closer to 2700 rpm. As long as everything continues to be equal with track conditions.....

If I may be so bold with the PO's thread. I'm thinking he and I are about at the same place; Pretty fast but its time to tighten down some details, yes?

I am running with my breather and a PCV valve. I've heard some folks say not to. Im not sure I understand what the difference would be at WOT. Can anyone shed some light on that please??? what do ya'll do?

thanks in advance!
 
The only way i would NOT run a PCV is if i had a pan e vac or a vac pump for the crank case.
 
I run the stock pvc system. I played with an exhaust evac system on the head pipes. It did create some suction on the hose, but I didn’t pick anything up so I removed the stubs and check valves. Had a friend that bought the battery powered Star Machine vacuum pump. He also didn’t gain any performance. It did help him with nagging oil leaks. I know people who realize performance gains with a pump. I just think we both needed a motor built with the idea of running a vacuum pump in mind. With ring choice to match.
 
Couple thoughts.
Torque Converter Stall: The number varies with how they are built and the torque applied. At low rpm and torque the car may start to move at idle or just above. Under high torque is when something close to the advertized stall speed comes into play. If you want to check the brake torque once, as a reference, get the number and your done. I don't see the heat issue for that but maybe that depends on the converter. A higher torque engine should stall the same converter at a slighterl lower rpm.

Traction:
Is the car's nose still high at rest?
For traction the car's suspension must be able to move up.
Its a whole system approach. I think the anti-squat in the leaf spring angle is important. That's what I'm doing for street and autocross, and its helped when using stiff springs. But I've seen cars lifted on the pinion snubber set just touching with the factory leaves & rear spring clamos moved to the front. The nose rises as does the rear, the body is almost level as it comes off the line. That's with slicks but the concept is important. The downward force on the rear tire depends on lifting weight.
 
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