just_ace
What will they rev too? Or what would rpm would peak power be at?

Anecdotely the ct20b happliy flows over what the cams/ecu allow. My gt4 would rev cleanly to redline, but i wasnt running 21lbs which i think is a bit much for the std gen3 and 20b.

Just my opinions tho.

I don't know what the redline is on GT4.  I have tuned this ST205 to 7800 rpm and it pulls hard to this in 1st and 2nd gears.  Will do more tuning at MTC where I can see whats happening in the higher gears.  Not sure but does the CT20B come standard on the ST205 engine?  Could the cams be different than what the 3SGTE SW20's have?
 
I know I am pushing it with regards the tune, especially at 21lbs. I am always looking for signs of knock on my logs. It seems very happy so far.
I have tuned thousands of EFI engines but never a 3SGTE.  Its a great engine.
 
Apologies for hijacking your thread mr2y
 
 

I'll try replacing the capacitors for the tacho in the cluster. Seems like a common thing with the MR2s.

 I am new to MR2s only buying my first one 4-5 months ago. I have recently bought a 1992 JDM  Rev2 GT & also have a 1991 NA which I think is also a Rev2 & neither of them seem to want to rev past 6000rpm. the 91 NA gets a bit noisey  past 5000-5500rpm &  revs slowly ,the 92 turbo is quieter over 5000rpm & will rev to 6000 but  power starts to drop off by then anyway,due I believe to a combination of the CT26 turbo & exhaust being too restrictive.
 

I just replaced both 10uF electrolytic capacitors in the tacho with Jaycar ones (63 volt 105 deg C) and I can rev it to 7400 without hitting the limiter. Idles at 900 now... might be a touch high but that's better than being 1400 too low.
 
Edit: mines a 1990 GT model BTW, Japanese import.

That was a good fix.  Catching up to me now. lol

TonyMR2
What I have been told is there is two speedo gear wheels (one for the 180 cluster and one for the 240 cluster).

I don't think that's right. It'll be the same speed cable for both speedos because the ECU reads the speed from the sensor in the speedo. The 240 cluster will just have a stronger spring for the needle.