The Ghost

Hey guys, can see from my sig. what I'm running. Been playing with tuning the tranny with the Xcal. Made many, many passes and a few dyno runs with a notebook in hand logging down speed/ RPM/shift firmness...blah, blah, blah. I've got this thing down to what is a nearly perfect set-up IMOP. My only Q at this point is "What is the max full throttle RPM you guys are willing to shift at ?" I tuned this thing to work on street tires and currently have the 1-2 at around 6400RPM but dropped the line presure to keep the tires stuck to the ground (dropped 60 ft times to 1.97, that is right at .10 better than before I started playing with it). BUT... I am kicking 2-3 and 3-4 at around 6700RPM, trying to get the most out of the car from here on to drop the 330ft and 1/8th times. 6700 seems to produce the best results, but I am a little concerned about what a stock motor can turn. Anyone got tech specs to share to convince me I'm OK? This motor is still pulling very nicely at 6700RPM but can the rods and bearings handle it?

Derf00

You've got that (6700 RPM) as the shift point for WOT or no matter where the foot is on the throttle? If it's just for WOT I wouldn't see this being too bad as long as you don't drive it like you stole it all day long every day. Then again, redline tends to be maximum conservative RPM for daily drivers. Unless you plan on doing some internal mods to the engine I might suggest dropping it back a few hundred RPM (right to redline) You may give up .10 on 60ft but your car would last longer.

I don't have specs on hand to 'convince' you but that's just my observation.

drbobvs

My xcal had rev limit at 6800. I cut it back to 6500 b/c the power just seemed to drop off after 6200. I found that in first at WOT, you were basically wasting time between 6400 and 6800 rpm waiting for the shift and when it did shift it was out of the power band again too soon. Since cutting down to 6500 RPM the shift seems to occur at bout 6300-6400 and gives a better pull when in second because you're back in the meat of the power band. Of course I have no times to show, it's just seat of the pants data if you know what I mean. Just my2C.

drbobvs

By the way I think stock rev limit is 6449 regardlesss of what the "redline" is on the tach. I just though 6800 was a little risky also.

757GT

The mechanical red line on the 05 auto is 6500, 6800 in the manual. Mine shifts at 6300. Mine made power on the dyno to 6500 but the guy who tuned it felt that a 6500 shift is to much.

The Ghost

OK trying to get pick data from these. I have my first shift at 6400RPM. But every shift thereafter is around 6700RPM. And yes this is only at WOT, I have it set up to be VERY smooth while driving on the street. Opened up the shift points so it's allways in the proper gear and doesn't do that awfull bog while waiting to downshift, at worst it will drop one gear when I stomp it from a roll. Also stiffened up line presure at low and mid RPM so I get a quick tight shift durring normal driving. MY thinking (this doesn't really mean much) based on a lot of strip time and notes. While at low speeds but pulling hard I have it at 6400RPM with a lower line presure to keep the wheels from breaking. Once the car gets moving and the chance of tire breaking lessens as well as the tourque load on the motor/drivetrain I have it shifting at 6700RPM. I have turned my very best times yet with it like this so I feel I am still making good power, but my concern is mechanically does anyone know if there is a greater potential for damage. Not building this motor myself I can't say, and I have not been able to find anything on the web that lets me know what's really inside this thing. I have a 65' w/a 351 long rod that can safely hit 8000RPM and gets shifted at 7500RPM. Gotta believe FoMoCo expected idiots like me to want to wind this thing up...Right?

drbobvs

I've read in other forums that the engine good for at least 6900rpm, beyond that I don't know. Practically speaking, since you'll never want to go higher, it doesn't matter what the exact number is before your engine blows up.

The Ghost

Thank You! And no I will not be going higher.

BRENSPEED

I have turned 6800 on the street just to do it and pulled all the way but at the track I shift at around 6100 but I have a 5 speed not auto. The key is when you shift to try to make your RPM's fall back down into where you are making good torque. I make my best torque in the area of 4400 and that is where I drop. Some cars may be different. On the dyno I always make peak HP at around 6100. I have pulled to 6500 on the dyno and it usually falls off but only by maybe 8 HP.

Ghost I am assuming you cross in 3rd....correct? I am sure you made your ET better doing so rather than letting it go into 4th right at the end.

The Ghost

Hey Brent, we've spoke much on the phone and you have sent me several upgraded tunes. You do good work, Thanks. But as for the Auto, it was better but never exactly like I thought it should be. I am new to this computer tuning so it took a lot of time to get the numbers I needed to set this thing up. Not to mention a real flounder once or twice! But I completley agree with the tourqe band and HP shift. My peak HP falls around 6100RPM also but the graph shows it's pretty flat from around 5800 to to about 6600. I tried to set my shift at WOT to stay in this range, so that after the shift it drops to around 5600 and is still good into the peak hp. And yes I cross in 3rd. But, after starting this thread I have dropped my 2-3 and 3-4 back down to 6500rpm. I began to think about everything that would be affected by high RPM and the one thing I forgot initially was the tourque converter. I did some surfing and concluded it is not a race unit and will probably experience some balooning at high RPM, so I'm going to play it safe with that one.