BUILD THREAD 84 Regal back half/caged/mini tubbed lq4/4l80e build

64nailhead said:

How does the ECU control line pressure?

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I’m able to increase it by percentages at different tps ranges per each shift

Is it really a project car if you have never considered driving it off a cliff, lighting it up, or selling it? Lol

After taking some time off and putting it on the back burner, got back to it with a fresh set of eyes,

So I still do believe the trans is bad, or has an internal failure somewhere, it may have broken shift valve springs, or bad shift solenoids from the symptoms, the temps stay low now that I’m able to get a better baseline reading after installing the cooler, and does rip the tires, but still over runs the gears, today it actually popped out of gear at one point. These pretty much describe my exact symptoms below.

Secondly, screw fitechs crap sensors, they fail to acknowledge the common denominator in all my issues that come down to their brand which is ultimately outsourced cheap Chinese junk, offering to replace them with the same garbage, the map sensor failed while driving, the tps failed causing erratic readings and fueling and shifting, And now the IAC, which seems to be the root of all the issues I’ve had with it. When I pulled it, it was stuck in the out position, replaced it with a standard AC234 since the delco is no longer available.

It idles smoother, afr is much more crisp, no more stumble or hesitation taking off or wanting to die after a rev,


Thanks

Quick update,

So after some occasional rips, the trans definitely let go, the continuous popping at WOT was the trans slipping. It was a shady story from who i purchased it from, he became a salesman instead of a friend with that deal, which made me just keep denying the trans was bad.

I pulled the diff as well, the dilemma is if I’m going to keep the 295s (26s) with a lower gear, or go up to some et streets 28/29, with higher 4.10s or minimum 3.73s. The 26s are way easier to find, more mileage, and way cheaper, they just look stupid with a shortened diff, compared to a nice big tire that’s triple the price and a fraction of mileage, but anything is better than the old beat up way too high 4:88s it had in it. the bearings are shot, and I’m ditching the spool since it’s going to be street driven, the chatter and chirping would destroy the new gears prematurely. Going with a truetrac and i realized they make 3.90 gears which I think would work best for the type of driving I do, and also for safety reasons if I lose a wheel.

But the good news is the engine is totally dialed in, it’s performing great after working out all the bugs with the Fitech

I plan on keeping this setup until
Next year, and than going fbody t56 and selling the auto setup as a lot. And a

6 month update,

After pulling the trans and diff, and let it collect some dust, the warm weather somewhat started here and motivated me to get back on it, the goal is to get an e/t on it this year.
4l80 is almost wrapped up with the rebuild with some goodies in it, going to pick it up and reinstall it next week, as well as a b&m progate shfter.

Going to drop the rear end off when I pick up the trans,

But I need some help if anyone has any input,

I should be pushing about 440-460, car should weigh around 32-3300 if not less considering it’s basically a shell with a power/drivetrain.

I’m running the circle d 245 mm single disc with a 4K stall

I’m at odds with what gear ratio to run with the 4l80. Car currently has 295/50/15s (26s)
They’re street friendly, and easily available.
Eventually I’m most likely going to purchase 2 Mickey Thompson sportsman’s for the 15x14 inch rims. I’m thinking 29s, and not sure how the tires run, what width would I be able to fit on those? Maybe 18?
Tire Diameter:
29.00 in.
Section Width:
17.60 in.
Tread Width:
15.80 in.
Minimum Recommended Wheel Width:
14.00 in.
Maximum Recommended Wheel Width:
16.00 in.


What gear ratio would allow me to be somewhat in between 26-29 with a decent overdrive rpm?
Car is going to be 95% street, Highway cruises, and occasional around town rips, but more roll/cruising hits. I would prefer to go lower than higher, with being able to stay in gears longer, and more rpm drop between shifts since the lq4 should have enough power to offset a lower gear ratio and I’ll be able To live with it.
It’s a gm car 12 bolt, doing an trutrac and 3.55 or 3.90? Or anything in between

Thank you!

bracketchev1221 said:

We put the 18X29 sportsmans on my friends car. He likes them and they fit will in the stock diameter wheel well. They are on a 14" wheel as well.

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Ok perfect, that solves one question, you don’t happen to have any pics of them do you?

What would you think be the highest and lowest gearing range for 26s and 29s would be?

So I called circle d today, with the 26s and my info they said I should be between 3.73 and 3.90

I may stick with 3.73s even with the 29s eventually to keep rpms lower at the cost of performance

I’m also going to redo my fuel system, the c5 ffr even from the dealer is showing 70 psi at the rail, hence why it’s pulling some fuel trim and extended hovering deceleration.

Going with a Holley bypass regulator, block one outlet Port, so feed to one rail, out the other to the regulator and running another -6 up front as a return out the bottom of it.

I purchased a 10 micron summit filter -6 male both ends to take the c5 ffrs place

Shifter is also installed, I ended up ordering the older style shifter cable bracket for the trans, the one supplied is for the transmissions with the short shift shaft and geometry most likely wouldn’t line up without resistance