V8 MKIV Supra from Saint Lucia.KHAOS!

[bambuko]

Regardless, a NA V8 will always have better response and build torque faster than a FI 6. The sudden spike of torque from a turbo is predictable, actually, it's just not as stable as instant torque that increases more linearly. Not saying a FI 6 can't put out crushing torque early in the power band (for example with two small and fast spooling turbos), it just has more of a delay (doesn't matter how relatively small or not that delay is, it is still *there*).

[pwpanas]

Originally Posted by bambuko

Regardless, a NA V8 will always have better response and build torque faster than a FI 6. The sudden spike of torque from a turbo is predictable, actually, it's just not as stable as instant torque that increases more linearly. Not saying a FI 6 can't put out crushing torque early in the power band (for example with two small and fast spooling turbos), it just has more of a delay (doesn't matter how relatively small or not that delay is, it is still *there*).

Even a big block, high compression v8 does not have a vertical torque curve. My point is that "early in the power band" is irrelevant - just downshift. At higher rpms (relative to turbo size) torque increases just as fast as with a larger displacement n/a, if not faster.

[bambuko]

Yes, but torque starts at a higher point in a larger NA motor, because it comes quicker when you first hit the gas. As I've already said earlier, a FI turbo'd motor can easily put out more torque but there is no way you can rationally argue that a turbo'd engine has the same response and instant torque as a larger naturally aspirated engine.

It appears that we can't come to an agreement. Perhaps you should go over to Toyota and tell them they raced the Supra incorrectly all those years, that a 6 cylinder is the better set up. Or the current Supra hybrid entering in LeMans soon. Or even better, go over to Nissan and tell them the same thing since that's what they also use a NA V8 in their GTR race car!

Or how about this: you're right. Feel better? Good night, chap.

[pwpanas]

Originally Posted by bambuko

Yes, but torque starts at a higher point in a larger NA motor, because it comes quicker when you first hit the gas. As I've already said earlier, a FI turbo'd motor can easily put out more torque but there is no way you can rationally argue that a turbo'd engine has the same response and instant torque as a larger naturally aspirated engine.

It appears that we can't come to an agreement. Perhaps you should go over to Toyota and tell them they raced the Supra incorrectly all those years, that a 6 cylinder is the better set up. Or the current Supra hybrid entering in LeMans soon. Or even better, go over to Nissan and tell them the same thing since that's what they also use a NA V8 in their GTR race car!

Or how about this: you're right. Feel better? Good night, chap.

No need to get stressed - I thought we were having a good, objective, friendly discussion. Apologies if I offended you.

Regarding Toyota's super GT racing, or any officially-sanctioned race event, there will be rules. Things like boost, displacement, weight, modifications, etc. are highly regulated. I'm sure Toyota was 'correct' in their setup, based on the rules & restrictions they had at the time. All that said, I wouldn't say they should have run a turbo (even if a rule was the only torque-related reason they didn't) - as I've already stated, turbos aren't ideal for roadracing due to their somewhat inconsistent power delivery relative to rpms.

[bambuko]

No worries. I'm not sure why Toyota went with the V8 (after initially going with a 4 cylinder in the early years of JGTC), I always thought the main reason was simply response. Besides the angle you mentioned, which was more predicable and stable power delivery, I don't know what other advantage a NA V8 would have over a FI 6 - esp one as great as the 2JZ.

Have a nice weekend.

[pwpanas]

Originally Posted by bambuko

No worries. I'm not sure why Toyota went with the V8 (after initially going with a 4 cylinder in the early years of JGTC), I always thought the main reason was simply response. Besides the angle you mentioned, which was more predicable and stable power delivery, I don't know what other advantage a NA V8 would have over a FI 6 - esp one as great as the 2JZ.

Have a nice weekend.

I have a bit more info on that. Toyota chose to replace the 2jz with a v4 because of JGTC boostXdisplacement restrictions. Running the 2jz with enough boost to overcome its weight difference over a v4 would have been against the rules. Running it with a low enough boost level to comply with the rules would have made it non-competitive. The v4 conversion also allowed the center mass of the engine to move rearward in the chassis (vs. the I6), which had a positive impact on handling.

It's really a shame. As you're well aware, at higher boost levels, the 2jz really shines. On race fuel and a few tweaks, an mkiv tt 6spd with the oem twins is capable of 450rwhp+. At the time, HKS had a prototype sequential twin turbo, with larger-than-oem turbos. For whatever it's worth, I firmly believe a 2jz-equipped jza80 could have done extremely well in JGTC. It was only that series' rulebook that kept the 2jz out of the limelight.

Sincere hopes you have a great weekend too!