Dyno graph and shift points

[jayro]

Hi all,
I am going to the dyno here in the next week (working on tuning my cams) and also was looking for my new shift points for optimum performance. I was thinking that you want the most area under the hp curve. So since there is about a 1k rpm drop between gears...I am thinking you should shift about 500 rpm's after your peak. Is this correct? I didnt know if staying in a lower gear past that would help. Does the lower gear aid in acceleration even if your not making quite as much power? Thanks

Jeremy

 

[jayro]

Anyone? MAybe wrong section?

Jeremy

 

[FastAndFurious]

area under the torque curve.

I was always interested in that subject as well.

I'm reading this webpage right now, and I think this page will explain everything you need

http://www.welltall.com/ymc/discovery/car/shiftpt.html

 

[Eric VerValin]

Ya know man... I was kinda just debating that same thing... I gotta get my car up there too.. probally wont be for another couple weeks for me tho.

 

[Phoenix]

You need to shift a tad higher , by doing so you will loose some HP (being higher) but when you shift right in the powerband you will gain more then what you have lost previously.

 

[NotSoSlowSHO]

The factory redline of 7300 rpm is a VERY good place to shift if you want everything the car has got.

No need to take it any further than that on stock cams, and short-shifting any will only slow you down.

 

[St Louis SHO]

The factory redline of 7300 rpm is a VERY good place to shift if you want everything the car has got.

No need to take it any further than that on stock cams, and short-shifting any will only slow you down.

My 3.2l with 3.0 cams stopped making power at 6k, if you tried to run it out to 7, it wasnt pulling.

 

[jayro]

Thanks. Thats what I always did before, but I installed Triflows over the winter so I am trying to adjust to get the most out of them. I am planning on the dyno this weekend. I will post my results....just looking for some insite on inturpritation (man I cant spell). The torque curve is alot different with the cams....it doesnt fall on its face at 6500.....it is a gradual slope down so it is still pulling hard up to about 7600-7800rpms

Jeremy

The factory redline of 7300 rpm is a VERY good place to shift if you want everything the car has got.

No need to take it any further than that on stock cams, and short-shifting any will only slow you down.

 

[jayro]

Bring the car up....the guy said he would give us a discount if I could get some cars together. Kind of a dyno day

Ya know man... I was kinda just debating that same thing... I gotta get my car up there too.. probally wont be for another couple weeks for me tho.

 

[FastAndFurious]

Thanks. Thats what I always did before, but I installed Triflows over the winter so I am trying to adjust to get the most out of them. I am planning on the dyno this weekend. I will post my results....just looking for some insite on inturpritation (man I cant spell). The torque curve is alot different with the cams....it doesnt fall on its face at 6500.....it is a gradual slope down so it is still pulling hard up to about 7600-7800rpms

Jeremy

And I think you can go higher rpm with 1st and 2nd gear than with the other gears because of gear ratio.

 

[Brett]

My 3.2l with 3.0 cams stopped making power at 6k, if you tried to run it out to 7, it wasnt pulling.

most would argue although the power does fall off at about 6k, shifting at 7 would put you in a better part of the power band for the next gear.

 

[boat]

Do it! Do it!

Ya know man... I was kinda just debating that same thing... I gotta get my car up there too.. probally wont be for another couple weeks for me tho.

I am probably going to be doing this. The more we have, the better chance for a discount per car.

Bring the car up....the guy said he would give us a discount if I could get some cars together. Kind of a dyno day

 

[NotSoSlowSHO]

My 3.2l with 3.0 cams stopped making power at 6k, if you tried to run it out to 7, it wasnt pulling.

Doesnt matter if it peaks, or even dips from 6k+

It is still making more power there than it would at whatever RPM the motor would drop to when you upshift.

And it gets you right into the fat part of the power band, instead of at the bottom of it.

Just take a video like this of my '89, doing a 0-70 run, then take a look at a dyno plot of the same car.

http://www.youtube.com/watch?v=WFS-I2ichMc

 

[St Louis SHO]

Dude I've driven many many SHO. My car would be faster shifting at 6200 than 7300. With tri flows I'm sure it makes power higher but only a synopsis run would tell.

 

[Eric VerValin]

See Boat and Bubba tell me I'm crazy for shifting at 6300.. lol It just feels right to me...


And I just now started remodeling that WalMart in your little city there... still waiting on a paycheck.. lol But definately I want to get a few of us on the same dyno so we can have a good idea of not only our own cars, but also the dyno if one of us goes to another around here. There is also the one on West Jefferson, and I'm not sure what they would want.

 

[hawkeye18]

Dude, you gotta fix that secondary opening point! They are opening waaay too early!

 

[NotSoSlowSHO]

Thats just a sample Dyno from a LONG time ago, on an old tune.

Things have been adjusted

 

[sho_sc]

I normally try and shift so that the result will put me near peak TQ in the next gear. Of course my HP/TQ curves look somewhat different.

 

[32MTX]

my 3.2 with 3.0 cams pulls its hardest at 6.5-7k

besides, I like shifting slightly higher so I'm at a higher RPM for the next gear.... I normally shift at around 7 or 7100

 

[FastAndFurious]

I shift at around 8k rpm in 1st gear. I think I'm crazy.. Haha
I haven't done WOT in second gear, so I don't know if 8k rpm would work for second gear.
Well I got stage 1 cams and other things for mods.