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Agree

I agree with that fact, I am in the same situation as your customer too. The only problem is in our class all of the cars are within a 100 or so pounds of each other. And my car is the only one doing this on the data file. Even though the cars are around the same weight and the transmission ratio is the same. When I am beside one of the other cars in our class. I am right there with them all the way through low gear, and as soon as it hits second, they fly ahead of me. But when it starts to accelerate again, I stay right with them. But it's that two or three car lengths after the shift that is killing me.

Hutch, you think putting a more aggressive rear ratio will help?
 

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Let us know

Let us know if it helps. I am going to try going from a 4.10 to a 4.30 and see what happens. I will also try the shift point as well. But let us know if it helps, especially if you take it out before the weekend.
 

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Fyi

If you want to bring a dead horse back well here it is! The thrust issue was resolve by putting a simple restrictor in the pump! It didnt have one! The car is running with the same trans & torque converter with out hurting anything! No mods to the bearings, no coating to the crank of any kinds, no surface finish to the face of the thrust on the crank, .007 end play no problems! Thats a done deal! The racers from this website help solve this problem by telling me to dyno the trans & check the cooler pressure, not by you! You were just sticking up for the guy at fault at the time, but that was all water under the bridge into you brought it up again!
Shitstorm? When thousands of dollars are being thrown in the garbage because of a simple mistake someone made dont you think anybody would turn into a shitstorm! I do! & so did the customer!
I got on here asking for your help! I thought everything was cool between us but I guess I'm wrong! This rpm stall on the gear change will get resolve with or without your help! Just like the thrust issue! Customers are #1 in my list.
By the way, If i knew it all why am I here asking you! I do know one thing for sure this customer has a problem & we are going to get to the bottom of it!

Hey man... just FYI so you will know, I tried going from a 4.10 to a 4.30 gear. And ran the shift point all the way to 8000 from 7400. No matter where the rpm dropped to it still flatlined and took over 1.2 seconds just to start climbing again. Also, the rpms at the finish line are the same no matter what the gear or shift rpm. With the 4.10's and shifting at 7400 it was 7039. With the 4.30's and shifting at 7400, 7600, 7800....etc. it was 7058.

A whopping 19 rpm's

So long story short, if you find out what is up with this guys car......keep us in the loop!!
Thanks
 

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What happens is the bigger gear makes the converter more efficient (less slippage) so your car should accelerate faster but rpm's through the trap stay close to before.If I posted the runs from the datalogger with the 4.10 compared to the 4.56 you see a distinct difference in converter slippage.

Acceleration, in low gear it might accelerate at tad faster...by seat of the pants feel. But the graph from the 5.92 with the 4.10 and the 5.92 with the 4.30 after the shift you could lay them across one another and they would almost look identical. By the way, the car ran the exact same e.t. after the gear change as well. But lost about a tenth of a mph. And like I said I only netted a 19 rpm increase in the traps.

Does that sound like a converter issue? Marty at Neal Chance swears there is no way, but I sure am beginning to lean that way.
 
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