clutch 2nd gear grinding

[mr2pwner]

Originally Posted by Gairloch

First, you're lugging the engine. You're just getting into the power band at 3000 rpm and it will make power up to 5250rpm.

Some people have reported that using a fluid like Red Line MT-90 or Penzzoil/GM Synchromesh have reduced grinding. I tried that and it did nothing for my transmission so I learned how to double clutch until I put a new(used) transmission into my car.

This is extremely common and comes up a couple times a year.

Thanks for the info, I was told by the dealer that I bought it off from that 2's often don't like to go above 4k RPM, this engine was rebuilt recently and I'm sorta new to MR2s and I certainly didn't want to do any uneccesary harm as this is a daily driver. Is it safe to take these up to 4500-5000 RPMs? Sounds like the engine is really screaming at 4k, coming from a n00b though.

[killermillermr2]

I dont know which engine you have but my 5sfe likes high reves. Doing 80 mph in 5th is at 4000ish rpm, and this is normal. the rev limit is 6300 (91). I will let someone with a 3s chime in now because I've had a drink or two and dont want to give misinformation

[Jshuntr]

Originally Posted by Jason.MZW20

Worn synchros.

2nd gear grind and 5th gear pop-outs.

add me to the list of people who have this exact thing.

[Gairloch]

Originally Posted by mr2pwner

Thanks for the info, I was told by the dealer that I bought it off from that 2's often don't like to go above 4k RPM, this engine was rebuilt recently and I'm sorta new to MR2s and I certainly didn't want to do any uneccesary harm as this is a daily driver. Is it safe to take these up to 4500-5000 RPMs? Sounds like the engine is really screaming at 4k, coming from a n00b though.

The dealer fed you a line of crap. They will rev to redline without any problem. They stop making power at 5250rpm though.

[fvillota]

so thats like the perfect shift point?

[Jason.MZW20]

Originally Posted by fvillota

so thats like the perfect shift point?

The perfect shift point is one that gives you your engine's peak torque output on upshift. That's usually around 6100rpm, as the peak torque on the 5SFE is 4400rpm for maximum acceleration.

[fvillota]

so if i shift my gears at 4400 i can get more agressive accelaration because i always shift at 6100

[Gairloch]

That's not the way it works. The point behind shifting is to stay in the power band as much and as long as possible. You're wasting your time revving to 6100. It stops making significant power at 5250.

[fvillota]

i see no wonder. i always stay in front but not by much.

so i shift at 5250 or 4400??

[Jason.MZW20]

Originally Posted by Gairloch

That's not the way it works. The point behind shifting is to stay in the power band as much and as long as possible. You're wasting your time revving to 6100. It stops making significant power at 5250.

Well the 5SFE isn't a 3VZ or 1MZ with double torque peaks (and a flat torque curve altogether). On the 5SFE, if you drop out of the peak torque range on upshift, you do lose time, but you also lose a little time revving the motor past its power peak, but only in higher gears. If you only rev to 5250, you'll likely drop to 3500rpm in the lower gears, which is way off the mark in terms of the torque peak. If this were a 3VZ/1MZ, 3500 is where one of the 2 torque peaks are, so it probably wouldn't hurt as much.

So, in 1st and 2nd gears, you'll need to push the motor to over 6000rpm, but because of how strong the gearing is, it won't matter that the motor doesn't produce any reasonable power after its peak because it revs pretty quickly.

1st gear @ 5250 drops you to 3250 on upshift to 2nd
2nd gear @ 5250 drops you to 3500 on upshift to 3rd

3rd and 4th gear drop to 4100rpm and 4200rpm (respectively) from 5250rpm, which is pretty reasonable.

[fvillota]

coool. thanks man! i understand now