unxpectederror

why does it seem like the 07-08 tC's do much better with boost then the older tC's?

did Toyota change something in the engine ? and if so what?

draxcaliber

aside from the different maf sensor, and a slight bump in compression, peak torque arrives 100 rpms sooner and peak hp is reached 300 rpms higher. so they do have a slightly different power band.

so 05-06
163 lb-ft torque at 4100 rpms
160 hp at 5700 rpms

07-08
162 lb-ft torque at 4000 rpms
161 hp at 6000 rpms

Mightygnu

I was just writing this. great information!

brett561tc

it "seems" like this because people put far too much care in what a dyno says. each one is different than the next. only way to make this statement true is to have the two model years, with the same kits and tune, get on the same dyno.

cessblood

I agree

CarbonXe

iTrader: (1)

The only way I'd consider the newer ones to do 'much better' would be if they were putting an average of 5 more whp per psi. And they're not.

soGone

The new engine is reworked from the old engine

You have to remember that they changed the way the SAE hp ratings are applied and the 07-08 tC's are actually about 5-10hp up on the 05-06 stock, using the older rating scale

This is most likely due to the slight increase in compression, mentioned above, which is good for low boost/no boost but may not be as beneficial for high boost application.


A customer’s 07 tC with Joe's old kit made 261whp at 6psi which is pretty impressive, once again that is at low boost.

Mr_Meaty

Yeah, I think it is mainly do to the higher compression, but it's not a great difference liek it is from teh celica gt to the celica gt-s, for example.
However, if you really want to up the boost, it is better to have LOWER compression to decrease chance of detonation, right?
So with lower compression, you loose a little power, but you get the ability to safely add more boost pressure which in turns gives you more power.

CarbonXe

iTrader: (1)

Yea, drop the compression and you can run lower octane fuel with boost, without worrying about detonation. Just an example, stock tC with 11 psi can run on 93 octane at minimum without detonation. tC with 8.5:1 compression pistons can run 17 psi with 93 octane without detonation. If you were to run 17 psi on stock 9.6:1 compression pistons, you better be putting in 103+ octane fuel.

Not 100% true, but it gives a general idea.

soGone

Correct, for high boost levels low compression is USUALLY the way to go because as you stated you can increase boost pressure to compensate which more than cancels out the increases you would have gained from a slight bump in compression.

Increased compression +low boost = little more power
Low compression + high boost = Much more power.

We could spend all day throwing ratios around and then build the worlds best tC!

Mr_Meaty

damn...93...best we got is 91 here

CarbonXe

iTrader: (1)

A gas station right down the road from me has 93 for only 3.04 a gallon!