3min3m2

*noob question alert*

I know the big limiting factor in the TC and its revs is the head.

If you have head built for 7600 RPMS, how many revs would it be safe to take the motor to(stock motor)

Thanks

tCyoung1

there is no point to rev the engine any higher because no power is being made. the head might help you produce more power but you will still have significant drop off in power after 6000 rpm.

2_much_tc

search....

3min3m2

did


And with IHE and a head, your RPM range shifts significantly to rev at least to 6750...

Not to mention it helps having more Revs when your 2nd gear ends a little early in a race

tCyoung1

i highly doubt that just head work would shift the power band that significantly unless you were turbocharged. now cams would do a better job if we had them. plus i don't think your stock short block would last long at those revs. the rods suck

kungpaosamuraiii

^^ Agreed.

It's not the head I would be worried about. The rods are more than strong enough for normal operation but you got one seriously undersquare engine for high revving. Tackle that problem before looking for high revving power.

Consider this:

At 7800 rpm, the 2AZ's mean piston speed will be about equivalent to what an F1 engine does during a race.

divisii

yep kunpaosamuraiii is right it's not the DOHC head it's rod/piston speed. (hmm, offtopic, an average 3 angle & extrude hone would be enough for most applications)

There's not much point goin past the rev limit unless U change the rod to stroke ratio/shorten the crank.

3min3m2

Frogot about the long stroke on the TC

Shaka_Z

yeah... our engines are strokers, so forget about higher revs unless you have dezod build the motor.... their race team runs an NA 2az that reliably revs to 7600, but alot more than just the head has been tweaked - valves, springs, rods, the list goes on.

tbh tho, it isnt the engine revs that are the weak point - its the transmission gearing (imho the transmission is a poor match to this engine in the tc). 1st should redline at 40 (we have more than enough torque for it) 2nd at 60, 3rd at 90, 4th at 135 with the 5th gear being an efficient cruise gear for economy. we really dont need a 6th gear, as we arent a super high revving honda or 200mph supercar. in actuality our rev range and powerband is closer to a diesel.

note that up thru 4th, my own preference is a 1.5 to 1 ratio from one gear to the next, whereas stock gears - 1st redlines at 30, 2nd 45, 3rd ~80, 4th 100 and 5th 135 - stop being consistent in ratio after 2nd. basically, we shouldn't be able to launch with any degree of briskness from 2nd gear, yet we can... and I for one have even been able to start rolling from a dead stop in 3rd!

anyway, I like the 2az... i really do. I just dont like the transmission ratios.

CuRiOuSfIsH

yuup! Dont forget it! Long stroke engines generally do not like to be revved.... but provides nice torque in the lower rev range.
But also remember, to have more revs you need better parts..... and for that comes costs.... costs Toyota doesnt want for the Scion ppl.

3min3m2

The auto tranny isn't any better on gearing...

nominal_asu

ive never seen a manual transmission that goes 40 in 1st, ever.

Also in most other cars i've driven you are able to start in 3rd, it isnt good, but you can.

Longer gears=slower acceleration=more people complaining that the tC is slow, the gear ratios are set how they are in order to extract a reasonable amout of performance out of a low powered engine.

Shaka_Z

I can name one car right off the top of my head whos emanual transmission can do 60mph at a 7000 rpm redline.

corvette z06. (note thast this is just off the top of my head, and I m quite certain there are many other cars both past and present across all price ranges that have 1st gears that go to 40+mph)

granted, the vette is a completely different class of car altogether, but given that, I dont think wanting a 1st gear that redlines at 40mph is too big of a stretch. also, like i said, the 2az has way too much torque with the 1st gear it has been given, in this particular application - it is geared more for an SUV than a sport coupe, and in fact this drivetrain combination was not chosen because it was most appropriate, but rather because it was an already existing combination that toyota could drop into the chassis with little effort and even less cost (hence more profit). if they were willing to sacrifice some profit margin, there are several other options they could have pursued and still brought the car in under 20k, and would have made the tc the preeminent coupe in it's class bar none.