Toyota 1HD-FT vs 1HD-FTE (2 Viewers)

[KiwiDingo]

How would the FT be any better low in the rev range? The only advantage from more valves is flow which would only be evident at high rpm, no? Genuinely curious. If you have curves for both motors I'd love to see them.

That's what I'm saying, it's not better in factory form due to the emissions regulation at the time. If the FT was tuned with the same AFR as the DT was allowed to be tuned it would be better.

It's not just about max flow. Having two smaller valves / intake runners instead of one big one increases the air velocity which is really important at low RPM. Not only is the air entering the cylinder a much higher velocity, it also enters at two different angles creating two different swirl rotations in the cylinder for more optimum fuel mixing and ignition events.

The piston combustion bowls are also very different in design. As is the injector location and angle it's sprays into the bowl. The injectors themselves are also different, all these plus other differences between the two add up to an overall better performing engine.

 

[suzuguru]

That's what I'm saying, it's not better in factory form due to the emissions regulation at the time. If the FT was tuned with the same AFR as the DT was allowed to be tuned it would be better.

It's not just about max flow. Having two smaller valves / intake runners instead of one big one increases the air velocity which is really important at low RPM. Not only is the air entering the cylinder a much higher velocity, it also enters at two different angles creating two different swirl rotations in the cylinder for more optimum fuel mixing and ignition events.

The piston combustion bowls are also very different in design. As is the injector location and angle it's sprays into the bowl. The injectors themselves are also different, all these plus other differences between the two add up to an overall better performing engine.

I know everyone's wants and needs are different, but how is the best tuning achieved on the FT? I would be looking for more power overall, but would love to have better low-end performance. However, I don't want to push it hard, as I am also looking for longevity of engine life and reliability.

 

[Douglas S]

That's what I'm saying, it's not better in factory form due to the emissions regulation at the time. If the FT was tuned with the same AFR as the DT was allowed to be tuned it would be better.

It's not just about max flow. Having two smaller valves / intake runners instead of one big one increases the air velocity which is really important at low RPM. Not only is the air entering the cylinder a much higher velocity, it also enters at two different angles creating two different swirl rotations in the cylinder for more optimum fuel mixing and ignition events.

The piston combustion bowls are also very different in design. As is the injector location and angle it's sprays into the bowl. The injectors themselves are also different, all these plus other differences between the two add up to an overall better performing engine.

It seems like you are making a lot of inferences without any real support to back them up.

Did emissions really change that much from 1994 to 1995? And how can you really quantify the effect of the air entering at "different angles" creating "swirl rotations" or the impact of increased velocity of air (why would it have higher velocity anyway, theoretically a more restricted valve setup would have higher velocity at low rpm). I'm sorry but it sounds like BS to me. I remember conversations on this forum from years ago when Graeme was developing his turbos and it was clear the advantage of the FT came at high rpm.

Just to be clear I'm not arguing that the HD-FT isn't superior because it is, but you seem to be making a whole lot out of a little.

 

[Dougal]

I know everyone's wants and needs are different, but how is the best tuning achieved on the FT? I would be looking for more power overall, but would love to have better low-end performance. However, I don't want to push it hard, as I am also looking for longevity of engine life and reliability.

Fit a more active turbo, intercool it and tune the pump for safe and clean across the whole range.