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What RPM would you shift? #3002637
01/06/22 04:21 PM
01/06/22 04:21 PM
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Posts: 27,908
Irving, TX
feets Offline OP
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Irving, TX
I got some numbers for my new toy and was trying to figure out how to best get it down the track.
5200 lbs with driver.
5 speed auto.
1st: 3.587
2nd: 2.186
3rd: 1.405
4th: 1.0
5th: 0.831

26" rear tire.
2.65 rear gear.

Would you ride the HP plateau or reach farther back and grab a bucket load of that torque?

Unfortunately, it'll be a little while before I can try it out at the track.

Kevin Alexander 2013 CL65 Baselines-2.jpeg

We are brothers and sisters doing time on the planet for better or worse. I'll take the better, if you don't mind.
- Stu Harmon
Re: What RPM would you shift? [Re: feets] #3002640
01/06/22 04:26 PM
01/06/22 04:26 PM
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Washington
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madscientist Offline
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If you want to go fast run the RPM up.


Just because you think it won't make it true. Horsepower is KING. To dispute this is stupid. C. Alston
Re: What RPM would you shift? [Re: madscientist] #3002642
01/06/22 04:41 PM
01/06/22 04:41 PM
Joined: Jan 2003
Posts: 12,593
Marion, South Carolina [><]
an8sec70cuda Online content
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Marion, South Carolina [><]
5200-5300


CHIP
'70 hemicuda...8 sec street car
'69 road runner 440 w/ Indy SRs
'69 road runner 440-6, 4 speed...Dad's ride
'71 Demon 340 resto project
'73 Chrysler New Yorker
'06 GMC 2500HD LBZ Duramax...toy hauler
Re: What RPM would you shift? [Re: feets] #3002649
01/06/22 05:12 PM
01/06/22 05:12 PM
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Posts: 2,534
KATY TEXAS
csk Offline
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lots of TQ, is that with the EFI intake you showed me , same heads ? very good, that should move that heavy car


1968 Charger COLD A/C Hilborn EFI
512ci 9.7 compression, Stealth heads, 4.10 gear A518 ODtrans 4100lb,10.93 full street car trim


Re: What RPM would you shift? [Re: csk] #3002653
01/06/22 05:23 PM
01/06/22 05:23 PM
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So. Burlington, Vt.
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fast68plymouth Offline
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Really nice numbers for “at the wheels” up


68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123
Dealer for Comp Cams/Indy Heads
Re: What RPM would you shift? [Re: fast68plymouth] #3002676
01/06/22 06:22 PM
01/06/22 06:22 PM
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Ontario, Canada
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Stanton Offline
Don't question me!
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Seems to me you'd want to launch at around 3k and shift at whatever rpm to be at 3k at the bottom of each shift. Then run it out at the top end.

Re: What RPM would you shift? [Re: an8sec70cuda] #3002680
01/06/22 06:28 PM
01/06/22 06:28 PM
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A Red State
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Originally Posted by an8sec70cuda
5200-5300


iagree


Kayse can't keep up at all now. lol
Re: What RPM would you shift? [Re: feets] #3002681
01/06/22 06:28 PM
01/06/22 06:28 PM
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S.E. Michigan
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That must be the latest supercar (Mercedes, wasn't it?)


Rich H.





Re: What RPM would you shift? [Re: ZIPPY] #3002706
01/06/22 08:24 PM
01/06/22 08:24 PM
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Michigan
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Transman Offline
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Run a shift loop at the track when you get there.

Start 500 below max power, and increase you shift points by 2 or 3 hundred until the car falls off for ET and MPH.

Then change your stall speeds on the line the same way until you get your best 60’.

Re: What RPM would you shift? [Re: feets] #3002707
01/06/22 08:25 PM
01/06/22 08:25 PM
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Bend,OR USA
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Cab_Burge Offline
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Take it to a 1/4-mile track and test shifting it at 4500, 5000, 5500 and 6000 RPM, then look at all the incremental numbers and decide what RPM worked the best scope
If it went fastest shifting at 6000 RPM try 6300, and then 6600 RPM, you need to find out what the car likes for the best results wrench up


Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
Re: What RPM would you shift? [Re: Cab_Burge] #3002715
01/06/22 09:02 PM
01/06/22 09:02 PM
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Posts: 2,156
IL
furious70 Offline
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9 GRAND AND DON'T LOOK BACK whistling


70 Sport Fury
68 Charger
69 Coronet
72 RR
Re: What RPM would you shift? [Re: feets] #3002733
01/06/22 09:50 PM
01/06/22 09:50 PM
Joined: May 2019
Posts: 407
Lake Villa Il
INTMD8 Offline
mopar
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Lake Villa Il
Originally Posted by feets


Would you ride the HP plateau or reach farther back and grab a bucket load of that torque?


5800-6000


Try this-

https://glennmessersmith.com/shiftpt.html#data


69 Charger. 438ci Gen2 hemi. Flex fuel. Holley HP efi. 595rwhp 475rwtq.
Re: What RPM would you shift? [Re: furious70] #3002734
01/06/22 09:50 PM
01/06/22 09:50 PM
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Irving, TX
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Irving, TX
Originally Posted by furious70
9 GRAND AND DON'T LOOK BACK whistling


AMEN BROTHER!

This is my Mercedes CL65. Bone stock. I'm changing the turbo bypass valves this weekend. That will allow us to tune the V12. The boost will be a bit higher and hold on longer. Most tunes add 100-110 torque and 60-70 hp.

The torque will be hard to hold since it already lights the tires at 50 mph. However, it's the torque that makes the car so nice. 60-130 mph locked in 4th gear took 10.2 seconds. The best it has turned using second and third gears was 6.9 seconds. Not too shabby for an old pig boat.

As for my 541 build, it's waiting on me to wire and plumb the EFI.

listings-1.jpg

We are brothers and sisters doing time on the planet for better or worse. I'll take the better, if you don't mind.
- Stu Harmon
Re: What RPM would you shift? [Re: feets] #3002795
01/07/22 06:54 AM
01/07/22 06:54 AM
Joined: Nov 2020
Posts: 348
Isle of Sheeps
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Most times at the track you ‘take it too the max’...

You can feel the ‘drop-off’ if you go past peak power... drive

Never found that ‘short shifting’ ever worked for me?

Saves the engine but kills the ET, (phone home) lol... fan


Carpe diem, quam minimum credula postero, thanx Horace!

There’s no point trying to fix stuff that ain’t broke,,, 'but if ain’t broke',,, you is not trying hard enough...
Re: What RPM would you shift? [Re: feets] #3003035
01/07/22 09:55 PM
01/07/22 09:55 PM
Joined: Feb 2003
Posts: 4,873
Houston, Texas
TheOtherDodge Offline
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Feets, leave it in drive... I had a E55 with a "level 1 tune" and went 11.80 with a "spinning 60ft". I have never heard, though I am sure it happens, where a driver controls the shifts on these cars and runs better than if they left it in drive. Just my .02. And for fun, with a tune, I estimate it to run in the mid 11's if you are on a decent tire.

Re: What RPM would you shift? [Re: feets] #3003238
01/08/22 06:21 PM
01/08/22 06:21 PM
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Prospect, PA
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In theory, maximizing the hp under the hp curve should yeild the best et and mph. This theory works well with my cars, but I have a stock torque converter. I think this theory breaks down with higher stall race converters when the motor is back into the converter at the shift recovery rpm. The cam LSA and ICL probably play a part as well, and mine are not conventional..

Your shift/shift recovery rpm ratios are 0.61, 0.64, and 0.71 for 1-2, 2-3, 3-4 gear changes respectively.

With that, assuming you have a tight converter, I'm in the 5700-5800 camp at least for 1-2, and maybe 2-3. The 3-4 shift.might be 5400-5500. That's just eye-balling the graph and pushing the shift recovery hp up close to the shift hp.

This has played out pretty well on both motors I had in my charger with a torqeflite (0.59 and 0.69) . My 508 peak power was about 5600, but after a bunch of track testing, I shift 1-2 at 6500, and 2-3 at 6200.



.


Re: What RPM would you shift? [Re: TheOtherDodge] #3003434
01/09/22 01:08 PM
01/09/22 01:08 PM
Joined: Jan 2003
Posts: 27,908
Irving, TX
feets Offline OP
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Irving, TX
I took it out for the last run of the 2021 Texas Muscle Car Club Challenge. It was an 1/8 mile whice is NOT where this thing belongs.
I was surprised the Michelin PS4S hooked as well as they did. It had to be in the track prep.
I left it in auto with sport on and ESP off. About 300 feet out it hazed he tires for a couple seconds. Naturally, it starts to feel good at the shift into third at 80 mph and speed builds rapidly but the 1/8 comes up quickly.
I was lined up next to a Challenger 1320 on stickies. He sent me home by a tenth and a half but I felt good about having 2 mph on him.
This thing is an awesome highway cruiser but it's short game is week.

Screenshot_20211024-114355_I30 Dragway.jpg

We are brothers and sisters doing time on the planet for better or worse. I'll take the better, if you don't mind.
- Stu Harmon
Re: What RPM would you shift? [Re: feets] #3003491
01/09/22 04:01 PM
01/09/22 04:01 PM
Joined: Sep 2003
Posts: 15,752
north of coder
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north of coder
boy, a tenth and a half ain't very much in the grand scheme of things.
you should be able to easily figure that out with not much practice.
pretty good outing i would say. up
beer







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