shift point discussion thread

lindertw · Apr 4, 2013

in an effort to not derail BMR/chad's thread, I figured we could discuss shift points here...

some quotes from the above thread to get the party started:

fdjizm said:
I might try going higher!, for further explanation I made this a while back. shows how short shifting can mess with your ET... I still hear people talking about "you don't make power up there why are you shifting that high" lol.

this is specific to my car and my power curve, results may vary.
rpm in the NEXT gear is very important!

BMR Tech said:
A lot of people don't analyze this stuff (proper shift points)

I have learned over the years on these type of combos, that the best ET and MPH usually comes from gradual decrease in shift points. For example, 7,000 1-2 shift, 6700 2-3 shift, and 6400 3-4 shift.

You can work the numbers, and place the next gear right at your peak TQ RPM.....

In your 6500 shift plot, if you shifted 3-4 at say 6000, you would probably gain 1-2 mph on your timeslip.

fdjizm said:
I noticed that too, the gears are very close together.
I really think I should shift 3-4 at 6000 so it falls back into the torque range.

I was about to ask Chad if he shifted at any less RPM for 3-4 too lol.

How does this one look?

ArtQ said:
Shift mine at 6800 and cross the stripe at 6800. Its had more than a few excrsions to 7200. Tore the engine down a few days agofor some upgrades. After 5 years over 1000 track runs it looked like a brand new engine inside. Bearings were perfect. Ford did a hell of a job on these engines.

BMR Tech said:
I am pretty sure I told Chad to try this, and he said it didn't work for him.....but I don't remember.

It has always worked for me. My last N/A car went 11.50's@118 with 340hp, and I used this method (gradual decrease in shifts)

It was a different set-up than the ones we are talking about, but the power curve was shaped similar, and I had 4.56 gears.

2DaDarkZide PR said:
This is VERY interesting.

I have 4.10s and 305/35R18 on 18x10 wheels.

Here is my dyno. What would you BMR and FDjzm recommend as something to try

I am always open new ideas. ESPECIALLY when people do more with far less than I have hehe.

fdjizm said:
Your HP barely falls off near 7k and 4500-5100 rpm is your chunky torque area.
3-4 should be like 6300 or so to fall back into that area.

I'd go...
1-2: 6800-7000
2-3: 6800
3-4: 6300

fdjizm said:
This is what I got with what I think would be good shift points for your car based on your dyno sheet.

You can probably take 3-4 to 6500 but it would be nearing where your torque starts to fall off, we want to be at the peak or just before the peak.

lindertw · Apr 4, 2013

fdjizm,

I have a stock 3650 5spd manual; 4.10 gears, 17" M/T ET streets (26.5" diameter) and my dyno graph. Any other info you need?

fdjizm · Apr 4, 2013

My car and your car are very close (almost identical with the curve)
Honestly I'd say the same applies to you as what I posted here

Only difference is you have 2 more rwhp than me and I am running 26.1" tires.
set that limiter higher and give it a shot bro!

lindertw · Apr 4, 2013

fdjizm said:
...set that limiter higher and give it a shot bro!

I'll need to get with JJ@WMS and have it bumped up a bit (and maybe a race tune) :boobies:

GT.350-R · Apr 4, 2013

I need to put mine on a dyno, so I can have one of these done.
It will be interesting to see how people benefit from this.

sbt1320 · Apr 4, 2013

Ever run this calc. on an automatic setup?

fdjizm · Apr 5, 2013

All I would need is the automatic tranny gear ratios + a dyno sheet to be able to tell.

BMR Tech · Apr 5, 2013

You're welcome.

Can't wait to see the results.

As for the shift points, fdjizm....you may as well go all out and place the RPM exactly at the peak TQ on the shift..... Don't slack!!!!

Try to get every gear to fall back to 4400-4500, see where that puts your shifts at.

Yes, same logic applies to auto cars.

fdjizm · Apr 5, 2013

I am thinking that if you get back to exactly peak torque you take the ride down on torque instead of taking the slight ride up if you were to hit right before the peak.

Though the only thing I am conflicted with is does the horsepower start taking over and negate the effect of the torque falling off anyway?

what do you think of my hypothesis sir?

2DaDarkZide PR · Apr 5, 2013

I love going to Atco having new things to try. Makes it more of a valuable run.

fdjizm · Apr 5, 2013

Looks like i'm going 6800, 6800, 6000 next time out

sbt1320 · Apr 5, 2013

PM'd data --- trouble posting for some #$%&^ reason.

fdjizm · Apr 5, 2013

Got it, what size are you tires?

5R55S Automatic 5 Speed Transmission
1st gear 3.22 to 1
2nd gear 2.29 to 1
3rd gear 1.55 to 1
4th gear 1.00 to 1
5th gear .71 to 1
4.30 gears

ever been dynoed?

sbt1320 · Apr 5, 2013

sent the dyno sheet with the PM let me try here again..

sbt1320 · Apr 5, 2013

ooops missed the tire question.... 305/45R18

fdjizm · Apr 5, 2013

dyno sheet didn't show bruh. are you trying to attach it?
click post reply, then click the little paperclip icon and attach the file if you can't post directly.

sbt1320 · Apr 5, 2013

View attachment 41133

fdjizm · Apr 5, 2013

Like most of us peak torque for you is at 4400-4600rpm.
But your gears are a bit higher than manual so to fall in that range it would look like this...

Since your 3-4 is a larger gap than the manual you would benefit from winding that gear out more, not sure how you change the shift point if it's rpm or MPH but there ya go!

You could get away with first being anything from 6250 to 6500 though.

sbt1320 · Apr 5, 2013

Petty close to where I am at with it now other than third gear which I will give it a shot it does seem to be laying down in high gear this could help. Best ET to date has been 12.46 w/entirely stock engine, I will let you know what happens with the high gear change. Thanks

fdjizm · Apr 5, 2013

Sounds good man, nice times let us know how it goes!

shift point discussion thread

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