LASTOFTHEBREED02T/A

iTrader: (15)

I posted this thread in the Automatic trans section, and as usual no reply's.

Please help...


A buddy of mine, Help me out Identify my TA's poor performance.
First of all, My rev limiter... Its set to 6500 RPM, but of course i payed no mind to that.
My shiftpoints on the other hand! I noticed my ride being a lil sluggish, but many said its just the stall feel, and it shifts right at 6000 RPM, which should be a lil higher, considering i have 3800 stall and needs that extension shift.

Im a lil bummed out about it, just want my ride to be tuned right, and me being pretty new to Modding, dont know what to ask for, and trust the pros to help me with my Ignorance.


So my question is, What would you set your rev limiter and shiftpoints too? And Whats the unsafe point with stock ls1 bottom end.

MODS IN SIG...


Thoughts welcome...

PGUFF

iTrader: (12)

I don't think the gauges are exactly accurate. Your cam won't like to be tuned any higher. Who tuned it?

LASTOFTHEBREED02T/A

iTrader: (15)

Doesnt the stall need that extra rev so it wont start at lower rpm's once it has shifted?

I know the gauge is not very accurate, but I have friends with similar set ups and their cars rev (SOUND) much higher than mine.

ULTIMATEORANGESS

iTrader: (4)

yes, have you been retuned since your cam install? and is your trans ok?

RPM WS6

iTrader: (3)

I think you may be confused. You don't need higher shift points simply due to adding a higher stall converter. The higher stall speed will actually increase your shift extension even with the stock shift points.

The ideal shift rpm for a given application will depend on your power curve. In a perfect world, you'd want to upshift at the point of peak horsepower and then have the rpms drop (shift extension) no lower than your torque peak. Then you'd want to be geared in such a way that you'd climb right back to peak horsepower again at the moment you cross the traps. But the world is not perfect, and neither are most street combos, so best results will usually come from shifting slightly higher than your peak horsepower, unless stall speed and gearing is perfectly optimized for your powerband.

You need to run a data log of your current shift points to see if your tach is accurate. With your cam and stock heads, I would think that shift points in the 6300-6400 range would usually be just about right, but those shorty headers you have might not allow the cam to reach full potential in that rpm range. It would be better to see a dyno sheet of your exact setup rather than to just guess.

z28241

iTrader: (13)

Agree with RPM WS6 100%, and since ur talking shift points, you also need a valve train that can support higher rpms.

LASTOFTHEBREED02T/A

iTrader: (15)

Here is my dyno sheet, And I have to agree that the shorties are holding me back.
I do have a set of long tubes and Y pipe heading my way in the mail as we speak. So that will take care of the restriction in air flow.

If you look at the dyno sheet, my Hp is still climbing at 6000RPM, not by much, but do feel my shifts should be around 6200-6300.

You guys input is much appreciated!!!...













The lines in red is with a Locked TQ, and the Blue is with it being unlocked.

LASTOFTHEBREED02T/A

iTrader: (15)

Yes sir, it has been tuned for cam and retune once the trans/stall upgrade was done.
The transmission is working great, strong and fast shifting.

LASTOFTHEBREED02T/A

iTrader: (15)

Help anyone...

Matt0matic

Rev limiter 6800-7k, shift around 5.8-6k. By the time you actually react to a RPM or shift light you will be 6.5k RPMs.

MikeG

iTrader: (33)

6400.

Matt0matic

The rev limiter is there for 'OH ****' moments you don't want to touch it. I'd rather over rev by a few hundred RPM than be against the limiter.

Matt0matic

Thought you meant actually shifting the car... disregard the last post- tell the computer to shift around 6.2k. But the best way would be at a track and keep moving the shift points til the car slows down.

RPM WS6

iTrader: (3)

Do you ever lock the TC other than on the dyno? If not, then based on the blue (unlocked) line, I would shift the car at no less than 6300rpm.

This might change once you do the LT headers. You'll need to re-dyno to know for sure.

LASTOFTHEBREED02T/A

iTrader: (15)

Yes, the only time the converter is locked, is at the dyno. With long tubes and y pipe, Do the shifts and rev go higher?

TransAmWS.6

I do not think that LT's should have any real effect on when the car shifts or how high it revs

LASTOFTHEBREED02T/A

iTrader: (15)

Ok, so if im having them intalled i wont need to retune, just shift point adjustment.

RPM WS6

iTrader: (3)

You may want them to go higher, but it won't happen automatically - you would have to make adjustments to the shift points in your tune.

You may find that horsepower won't drop off as much or as early with the LTs. So the ideal shift point for your setup may be different once the LTs are in place.

I would get another tune. Shorties are barely any different than stock manifolds, so the ideal tune for a shorty setup will not be the same as for LTs. Install the LTs, then re-tune and see what the new power curve looks like.

LASTOFTHEBREED02T/A

iTrader: (15)

Thank you all very much guys!!! Always great help...

RPM WS6, Great breakdowns for us noobs as usual

gnx

Shift at 6300 and set the limiter at 6800 max to stay safe with the stock bottom end. The long tubes will help the top end a lot while moving everything up a bit. I would wait till you get the lt's before paying to reset everything.