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"Floating" RPMs? Shifting resistance? (06 S/C)

2.0L LSJ Performance Tech 205hp Supercharged SS tuner version. 200 lb-ft of torque.

"Floating" RPMs? Shifting resistance? (06 S/C)

Old 10-15-2016, 07:23 PM
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Unhappy "Floating" RPMs? Shifting resistance? (06 S/C)

Setup:

-- Brand new steel manifold exhaust header. (Stock header had a crack in it. I also had to replace my o2 sensor. (It was causing the RPMs to bounce when idling.) That's been fixed and my car idles at a nice 900-1k.

--Stage 2 clutch. (Car only has 120k. Previous owner did not specify when the clutch was installed or if it was stock. It seems sort of loose if I move it physically.)

--Typhoon K&N Air intake.

-- The rest is mostly stock, from what I can tell.

The problems:

-- If I'm driving respectfully, the car shifts smooth at 3k RPMs. Anything lower and it bogs. I've read this is pretty common. However, if I get the car really rolling and open her up to 6K RPMs and shift, even though my foot is off the clutch, the RPMs never really go back down and the car has a 2 second delay before it kicks into gear. It doesn't do this every time but it does it often.

Research online told me this was due to the ECU and electronic pedal. It also takes a bit for the RPMs to drop when engine braking, but it drops quickly when clutch is pressed in. I am not super experienced or anything when it comes to manuals, but I've driven 3 cars. (One of which being a modded Celica GTS, and it's super smooth compared to mine.)

-- The other problem is if I'm upshifting or downshifting into 2nd gear, it feels as if it doesn't "slide" into gear. Instead there's a slight pop-feeling. It doesn't take much force, but it's not as smooth as the other gears. I'm wondering if it's a busted syncro, or something easier like the shift pin? Not sure.. I've noticed it's also happening with reverse. Maybe even bushings?

I'm really hoping it isn't the clutch or transmission. I'm no mechanic though, and I really want to learn more about these cars.

Thoughts? For anyone reading, I appreciate your time. There's just too much I don't know. Lol
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Old 10-15-2016, 09:52 PM
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one of 2 things is happening when you lay into it and after shifting the rpm doesnt come down 1) the tires are spinning, or 2) the clutch is slipping. these cars were known stock for having the clutch slip if you spin the tires through 1st gear and grab 2nd quick. because of the instant torque these cars make and the low road speed it causes a lot of strain on the clutch and it will slip. the fix here is dont spin the tires through 1st gear then shift. usually they dont do this with a performance clutch, however its still possible. generally the best way to drive them hard is to be a little more gentle in 1st gear and try not to spin the tires, get into 2nd and have fun.

its nothing going on with the electronic throttle. in a manual transmission car when the clutch is out and car is in gear the engine is coupled directly to the wheels. if your driving with your foot on the throttle in 3rd gear at 3000rpm and let off the throttle and car is still travelling the same speed, so the engine rpm wont just drop, as now the engine is being driven by the wheels. the car will start to slow down from engine braking, but it doesnt happen instantly.

these transmissions arent the smoothest shifting, especially 1st to 2nd gear. the gear ratio change is quite steep between 1st and 2nd and contributes to this. a bad syncro will give a very stiff shift and usually a grind.

i dont think there is anything wrong with your car, your just feeling some quirks of these beasts and will get used to it.
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Old 10-16-2016, 09:26 PM
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Thanks for the reply, Sharkey.

I tested out some things, and going easy in 1st, then gunning it in 2nd works out really well. It's been feeling a lot better with the new knowledge you and the rest of the forums (searching topics) have given me. However, I still feel uneasy about 2nd gear. It seems to act like you need to "pop" it in gear, but it feels very secure once in place. Do you think it's something as simple as bushings?
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Old 01-25-2019, 04:35 PM
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its inside the ECM, there is shift Tq parameters that i adjusted when i first got HPT. still, its more preferred towards user defined drive ability and feeling how you like to drive(street tuned + many hours, many...) lol
totally i've adjusted from 2-3, 3-4, 4-5 which made shifting smooth at cruise/wot without trouble or stupid "not ready snags" when all that was needed was a Electronic adjustment on the Transmission Tables... -_-


floating rpms: are inside the ECM program as well(stated in tandem with DFCO rpm disable & transmission>RPM(in gear or P/N hysteresis) i lowered overall to a comfy 1000-1100 rpm. anytime i take it out of gear while rolling - i will idle at 1100 and will cutout/disable at 1000. and DFCO will be on when im in gear/packpressure till 1000=2-3mph.
this have given me a smooth transition from gear to gear and down shifting, you need to RPM match your gears with the clutch(not like the diesel trans's w/out clutch) otherwise your syncro's will have less lifespan than if you did, since you're not having the syncro's compensate for RPM difference(increasing from the drag on the clutch as well as forcing your syncro's to compensate spin of driveline to gear selected - aka have a midget piggyback ride a body builder up a hill..puts a lot of excess strain on the mating parts.
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