[danhr]

I'm curious on what the car will 60' with the 4c and 3.73s.....

[chris12]

Awesome post. Thanks for sharing results......

[Snowblind]

Originally Posted by danhr

I'm curious on what the car will 60' with the 4c and 3.73s.....

Early results below.

Originally Posted by chris12

Awesome post. Thanks for sharing results......

Appreciate the kind words.

We had a very small window tonight at Atco, their were thunderstorms predicted and unfortunately the weatherman was spot on. The Circle D 4C is in and I was itching to try it out, I knew I would only be able to make a couple passes (3) and I was just feeling out the new converter. I data logged my 3rd pass only and of course, I had some wheel hop on that pass. The DA was 2K+ at 5pm so I knew it would take a miracle to better my PR so I wasn't expecting too much. My quickest 60' to date on the stock converter is 1.56 (only once in -1K DA) half a dozen 1.57's and the majority of my runs are in the 1.58-1.59 range. No other tuning changes have been made since the install, my tuner said he didn't need to do any tweaking with the 4C. My car is #787






Fraxum is in the left lane in pass #2. He pulled right into the staging lane from the street and made his best 60' to date, 32 lbs in the back tires and all, go figure.

Slip #3 is against a 2018 Mustang GT...his number is 2018 coincidentally. He had Michelins on the back and said he was stock, I am not sure if they are factory stock or not, I just took a glance at what he had. Nice guy.

I used an idle stomp on each pass, I was in line to make a 4th pass and I was going to stall up and hit it hard....it preceeded to lightning...game over. I'll take the info and build on it for next time.

[danhr]

Stop....doing....so....good....

You are making harder on the rest of us. Lol

Have you tried messing with tire pressure or anything, or you just working out the launching first?

Either way... killer times, especially for the DA.

[Snowblind]

Originally Posted by danhr

Stop....doing....so....good....

You are making harder on the rest of us. Lol

Have you tried messing with tire pressure or anything, or you just working out the launching first?

Either way... killer times, especially for the DA.

Lol Thanks. In my case, the MT R's like 18 lbs and a healthy burnout. I have tried other pressures but this seems to be best for my set up.
I know Ultra is going to ratchet it up so I gotta keep my foot on the gas.

[PRAY]

Those gears, on that tire and no tuning tweaks for the 4C. That's a bold move Cotton, I hope it works out for you. I think you are going to be faster with your combo if you foot brake to 2,800 or so and drive it out. 18psi is perfect for those tires. Did you consider a 3C?

[bhillakaiceberg]

Nice work, given that DA! When I switched to my 4C, I made no tune adjustments either. Still was using 26in tire and Stock 2.77 gears.

I literally went to the track and left off idle and boom..mid 1.4s from previous pre 4C low 1.5s.

We do have GREAT prep here in the Maryland.

[PRAY]

Originally Posted by bhillakaiceberg

Nice work, given that DA! When I switched to my 4C, I made no tune adjustments either. Still was using 26in tire and Stock 2.77 gears.

I literally went to the track and left off idle and boom..mid 1.4s from previous pre 4C low 1.5s.

We do have GREAT prep here in the Maryland.

Jim's combo is a little out of norm for us though. I think the 2.77 really loads the 4C on the hit. The 26 tire factors in as well. So with Jim's deal the 3.73 isn't loading the converter as hard but will run through 1st much faster. My thought is with that deep of a gear and that much stall it will shift before the 60ft skewing the results. The other big detractor is with that much slip and the stock ported IM peaking at 5,700 his shift recovery unlocked will be well above peak power, not just peak TQ. We know that with even bolt on cars we can't lock the 4C before the very top of 2nd or the shift to third. So for almost three gears he is well beyond peak HP if he is using 6,500 shift points. That will slow the E.T's down and scrub MPH.

This combo could be the perfect candidate for a ported MSD with proper tuning to get some shift extension and power during that time while the converter is unlocked. I can't imagine the car didn't hit the limiter on the 1/2 and possible the 2/3 maintaining the original shift MPH. I had to drop 5 mph out of my 1/2 and 3 mph out of my 2/3 to stay off the limiter.

The opposite to that argument is that the gear isn't loading the converter and weight has been removed from this car that may help the converter slip issues with the 4C prior to lock up.

I know when I popped my 4C in I went 10.99 in 2K DA with a 1.44 60ft. But that was on a 28" tire in a much heavier car which loaded the converter much harder. I still have never once been able to leave off of idle without blowing the tires off. Hopefully soon I will be able to.

I am curious to see if this combo will mid 1.4 due to the mismatch. Now a 3C which slips much less would take better advantage of the gearing and tire height currently being used. With the tighter converter and the gear making up for the lack of stall speed we could see better 60ft's with much higher mph in the end.

Just some thoughts.

[ULTRAZLS1]

Good results. Obviously a 10.7 car in good air.

I’m also glad to see the converter didn’t seem to hurt your mph given the DA.

I got a couple things planned for this fall nothing crazy though we will see. I should be in the 10.7 range as well

[ULTRAZLS1]

Originally Posted by PRAY

Jim's combo is a little out of norm for us though. I think the 2.77 really loads the 4C on the hit. The 26 tire factors in as well. So with Jim's deal the 3.73 isn't loading the converter as hard but will run through 1st much faster. My thought is with that deep of a gear and that much stall it will shift before the 60ft skewing the results. The other big detractor is with that much slip and the stock ported IM peaking at 5,700 his shift recovery unlocked will be well above peak power, not just peak TQ. We know that with even bolt on cars we can't lock the 4C before the very top of 2nd or the shift to third. So for almost three gears he is well beyond peak HP if he is using 6,500 shift points. That will slow the E.T's down and scrub MPH.

This combo could be the perfect candidate for a ported MSD with proper tuning to get some shift extension and power during that time while the converter is unlocked. I can't imagine the car didn't hit the limiter on the 1/2 and possible the 2/3 maintaining the original shift MPH. I had to drop 5 mph out of my 1/2 and 3 mph out of my 2/3 to stay off the limiter.

The opposite to that argument is that the gear isn't loading the converter and weight has been removed from this car that may help the converter slip issues with the 4C prior to lock up.

I know when I popped my 4C in I went 10.99 in 2K DA with a 1.44 60ft. But that was on a 28" tire in a much heavier car which loaded the converter much harder. I still have never once been able to leave off of idle without blowing the tires off. Hopefully soon I will be able to.

I am curious to see if this combo will mid 1.4 due to the mismatch. Now a 3C which slips much less would take better advantage of the gearing and tire height currently being used. With the tighter converter and the gear making up for the lack of stall speed we could see better 60ft's with much higher mph in the end.

Just some thoughts.

Is the locking issue related to the 4c or a tuning issue?

I been looking at the fti 3800 street racer lock up series as another option over the 4c

Are all converters going to have this issue ?

[Snowblind]

Originally Posted by bhillakaiceberg

Nice work, given that DA! When I switched to my 4C, I made no tune adjustments either. Still was using 26in tire and Stock 2.77 gears.

I literally went to the track and left off idle and boom..mid 1.4s from previous pre 4C low 1.5s.

We do have GREAT prep here in the Maryland.

Thanks homie. I wasn't expecting much yesterday, just a few shakedown passes and collect some data.

I get people asking me how to get faster (probably only a fraction of what you and Brett do) and I just posted this to show that not every trip to the track is a PR....you need to put in the work and build on it.

If I don't see you in Maryland this month, I will see you at CamaroFest.

[PRAY]

Originally Posted by ULTRAZLS1

Is the locking issue related to the 4c or a tuning issue?

I been looking at the fti 3800 street racer lock up series as another option over the 4c

Are all converters going to have this issue ?

Even the stock converter doesn't lock till third. So it's not per-say a tuning issue but the more stall/slip you add the worse it gets. Just like the 2D in the Silver bullet "locks" before I want it to. That is simply due to the fact it is a 258mm vs. 245mm and it has more surface area and less slip. I wish it was a little looser. I would like to get some high 1.3 60fts and run bottom 9's with a P1X.

[Snowblind]

Originally Posted by PRAY

Those gears, on that tire and no tuning tweaks for the 4C. That's a bold move Cotton, I hope it works out for you. I think you are going to be faster with your combo if you foot brake to 2,800 or so and drive it out. 18psi is perfect for those tires. Did you consider a 3C?

I agree with you, as I was driving home I was reflecting on the slips and thought the ported MSD is probably in my near future. I didn't want to do it, but my setup is screaming for it now. Loading up on the car and getting it to stick will be next. I never really considered the 3C because I am not sure how much longer I will use the 3.73 gear set, I think the 3.27 unit is the ticket and the 4C seemed like the right choice with future goals in mind.

My only data logged pass was the slight wheel hop run so I don't have a solid read, but my 1/2 shift was 6200 on that particular run and all the rest are dialed in at 6500. I did not hit the rev limit on any run. The converter locked up in 3rd iirc.

E80 content. 28.5 degrees timing. No tb closure. Engine temp was 207 and IAT's were 99. I'll have to look at shift recovery when I get home. 3670 raceweight including me.

[Snowblind]

Originally Posted by ULTRAZLS1

Good results. Obviously a 10.7 car in good air.

I’m also glad to see the converter didn’t seem to hurt your mph given the DA.

I got a couple things planned for this fall nothing crazy though we will see. I should be in the 10.7 range as well

Thanks bro. A negative DA pass would have been awesome but ya get whatcha get. Obviously I haven't found the sweet spot for the combo yet, but I will.

I was trying to carry the torch for a ported stocker IM but I may have bite the bullet and go aftermarket.