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Discussion Starter #1
I put over 12K miles on a mean 07 GXP manual before someone pulled out in front of me to end said car's life.

I then purchased a mean 08 GXP auto as I was told that both are awesome. I drove an auto and was happy with it so purchased this car sight unseen with 8kmiles. Same color.

My issue/concern/question has to do with how this auto works. I do not think anything is wrong as I am up to 11K miles (averaging about 26.3 mpgs) and no issues vince hasnt fixed. I drove it stock, tuned with cortex and tuned by vince/trifecta.

All were very similar as to my issue, which I am unsure if I can explain well enough.

I have driven many autos. I have a V10 excursion, V8 Bronco and G8GT currently all auto and they do not behave like the Sol. In these vehicles, when I hit the gas from a stop, the rpms are close to the output of the motor and when I lift a little or apply a little more pressure to the gas pedal, the rpms change slightly. When the vehicles shift, the rpms drop.

In the sol, when I start from a stop, the rpms jump to 3k most of the time and do not change at all with next gear change, and when I lift, they drop almost 1k rpms. If I lift, and get back into it, the rpms will jump 1000-1500 most times. In the manual, I could accelerate quickly (quicker than most) while shifting at 2500, but cannot accelerate as quickly in the auto if I attempt to keep rpms below 3k. Also, in the manual, if I floored the car in 5th at 50, rps would not jump at all. I understand this is due to trans but why do the rpms in this auto jump so much?

What controls this? Is it the torque converter? The manual would get better mileage than this auto, mainly due to time spent in neutral at below 1k rpms which I do not get to do now. I can keep at 3k rpms without the turbo kicking in also. When I mash it, it will shift and move out quickly. It also shifts very quickly. I am concerned that the rpms from a stop are higher than they need to be while not accelerating as much as 3k should in the manual. I know the auto is a slush box and cannot compare the 2...but the G8 is now where near the same. Maybe I am comparing V8s to turbo4s wrongly...but would like to understand more about what is happening.

Is this understandable?

Thanks for reading.
 

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I think it's understandable. Let me talk a little generally, keeping in mind I also have 17yrs experience with my Bronco E4OD which has never been rebuilt....

This car if you nail the auto you have lag, and turbo lag. I have not tried putting the auto in first and punching it to see what happens, I'd expect like a manual I will be needing to manually shift the auto up very quickly.

This isn't a performance tranny IMO, it's slow with nailing and tranny downshifting to get going with the turbo. On the other hand, if you have the bronco, and likely excursion, those things down shift and do nothing, lots of noise, no power. And gear to gear is slow (RPM drop), whereas as you mentioned the one nice thing about this tranny is that it at least handles gear to gear shifts very smoothly, you don't drop RPM much.

So while I have not done any 1/4 mile stuff I'd think the key is in takeoff with putting your foot on the brake some to bring the RPM up a little, and then launching, while I'm not sure how much you'd gain by manually shifting the auto vs. letting it run to redline and shifting itself.

Not sure any shift kit will help since that's not the problem, I really think much of the issue is getting the motor involved, which is why you see the RPM jump so quickly once that motor/turbo really spool up. Torque convertor and maybe messing with stall speed? I just don't know enough about it to comment, but perhaps someone else does.
 

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Discussion Starter #3
not concerned about 1/4 times so much as I feel the motor is making more noise than power. At 3k the turbo is not putting out over 2-5 psi. At 2k-3k, the bronco, excursion and G8 are moving out. It is like I need more RPMs in the sol to get it moving...the G8 has about6k redline and excursion is about 5400 so not too much diff.

I bet its normal, but what controls it? Is it inherant to this auto tranny, would a different torque converter or stall change this?
 

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At 2-3k I'd have to look at graphs, but the motor by 3k should have a boost heading toward 22psi if you have a tune. The boost is quick and from what I recall 2k or so it will kick in and before you know it, you're at max boost and your redline around 6250. These are different motors though, my bronco weighs 5850 lbs with a 351v8, and it has low torque, NA, and consistently builds speed for a little bit (i.e the strong turtle approach unless I put in a built motor). The Coupe GXP has a slight lag, and then is like a rocket to redline, and nails the next gear on it's own WAY faster than my stock E4OD in the Bronco. Have you owned a turbo before? Lag is not good, but man, when the turbo kicks in, you should be feeling massive torque (it's rated at more than a stock 5.8v8 bronco), and lag should not be much, it's usually very quick to come on, where I find an issue is when I am in just in drive and say coming around a corner or something, and then I punch it. I have not played with downshifting the auto.
 

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Discussion Starter #5
This is my 5th turbo car. I understand lag and am not complaining about that.

I can hold this car at about 3k til through third and hardly boost. I do not think this is broken as I am only at half throttle. This is my normal driving style during commuting. If it give it a touch more it will boost and get right after it. With the manual tranny, during same non-spirited commuting, I would accelerate the same as I do now with little to no boost, but never go above 2500 rpms. My complaint is that I am now pushing 3k rpms to go no faster than the manual but consuming more gas. I know the manual is more efficient and maybe that is the issue all together.

I am trying to understand what it is doing and what part would affect this more...I am ok to leave it alone because nothing is broken. Wondering what would make it better.
 

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As I understand it, boost is determined by torque required. Cruising at any RPM doesn't need much, but hard acceleration will cause boost to ramp up. Your car sounds normal to me.
 

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Discussion Starter #7
I agree it is probably normal.
What part of the car causes it and is it adjustable? As in-can I buy a stall and change this? I am not extremely displeased as is, just seems I would like it if it were different, say 5-1k rpms lower. Maybe just the tranny is to blame....as in "auto tranny suckage".
 

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The ECM and TCM work together to determine torque and boost levels. I suppose a tuner could rework the programs.
 

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A stock Kappa reaches peak torque at 2600 RPM.

A tuned Kappa reaches peak torque at about 3600 RPM.

Therefore your auto car is going to want to run at 3000 ish for max efficiency.

I am pretty sure what you are describing as a concern, is the combination of a 4 cylinder car and an auto tran. And having someone reprogram it to shift at lower RPMs will probably kill your efficiency because you will be trying to drive at well below peak torque.

With my manual tuned Redline, the car prefers to be running around 3000 RPMs, just the way it likes it. Again, this is a 4 cylinder car; if you run outside of it's efficiency curve, it is unhappy. At cruise on the highway in overdrive, the car will be happy running at lower RPMs; but in those conditions there is no need for peak torque. When driving around in stop and go traffic, trying to run down in the 2,000 RPM range at shift points will bog the car down, kill your efficiency, and result in excessive carbon build up.

If you go WOT; does the car command full boost and run to redline before shifting? If so, then everything is working correctly. When you are grandma driving, it is still going to want to at least get to 3000ish RPM before it shifts, to keep you within the efficient torque range.

We have an 06 auto Colbalt SS N/A with the 175 HP 2.4. And it drives and shifts the same way. Even just putting around, it will tend to get the RPMS up pretty good, before it shifts. Not quite as high as the 2.0, but the same idea. I am sure the reason it shifts a little lower is because the higher displacement engine will reach peak torque a little lower in the RPMs. You have to keep in mind that when you are driving the 2.0 and not in boost, that it is a pretty darn small engine to be lugging around a 3000 lb car. :lol: So when running in N/A mode, that poor little engine needs to have some RPMs to make torque.
 

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I have yet to see any examples of TCM tuning on our cars. If you find one that would be good info to share.

The auto gets less MPG than the standard because it expends energy operating the transmission AND transmitting torque to the rear wheels. Its very rare for an auto to be able to match the mechanical efficiency of a standard transmission. Just a lot more moving parts, pumps and slippage.

Driving around at 2500 RPM is not something that I have ever recommended. Driving at 2500 RPM and hammering the throttle is also not something particularly good to do. The ECM adjusts to a lean condition over time at low throttle and RPM settings and when you hammer it when in high mileage mode, you will experience pinging. Sustained pinging can be death on these motors.
 

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Discussion Starter #12
A stock Kappa reaches peak torque at 2600 RPM.

A tuned Kappa reaches peak torque at about 3600 RPM.

Therefore your auto car is going to want to run at 3000 ish for max efficiency.

I am pretty sure what you are describing as a concern, is the combination of a 4 cylinder car and an auto tran. And having someone reprogram it to shift at lower RPMs will probably kill your efficiency because you will be trying to drive at well below peak torque.

With my manual tuned Redline, the car prefers to be running around 3000 RPMs, just the way it likes it. Again, this is a 4 cylinder car; if you run outside of it's efficiency curve, it is unhappy. At cruise on the highway in overdrive, the car will be happy running at lower RPMs; but in those conditions there is no need for peak torque. When driving around in stop and go traffic, trying to run down in the 2,000 RPM range at shift points will bog the car down, kill your efficiency, and result in excessive carbon build up.

If you go WOT; does the car command full boost and run to redline before shifting? If so, then everything is working correctly. When you are grandma driving, it is still going to want to at least get to 3000ish RPM before it shifts, to keep you within the efficient torque range.

We have an 06 auto Colbalt SS N/A with the 175 HP 2.4. And it drives and shifts the same way. Even just putting around, it will tend to get the RPMS up pretty good, before it shifts. Not quite as high as the 2.0, but the same idea. I am sure the reason it shifts a little lower is because the higher displacement engine will reach peak torque a little lower in the RPMs. You have to keep in mind that when you are driving the 2.0 and not in boost, that it is a pretty darn small engine to be lugging around a 3000 lb car. :lol: So when running in N/A mode, that poor little engine needs to have some RPMs to make torque.
Thanks for that reply. It explains it a little better and I will live with it. Yes, the car runs very well at WOT. It gets to 21-22psi and shifts with very little drop in rpms, much quicker than I could with the Manual. I guess I just miss the third pedal sometimes.
Cheers
 

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