I've been thinking about this for a little bit comparing my current D-max truck to the gasser I built a few years ago trying to figure out where the disconnect is.
My old truck was a 408ci (about 6.7L), turbocharged, about 9.4:1 compression, and I ran it about 16-18 psi, with meth injection. It dynoed 575/640 at 14psi, never dynoed it at higher boost but ran low 11's at 120mph at the higher boost level in the 1/4.
D-max is 6.6L, runs about 30 psi, 17.5:1 compression. I haven't dynoed it but it's run a low 13 at 102 mph in the 1/4.
Both trucks weigh about the same. Gasser was a 2001 4x4 ECSB, this one is a 99 RCSB 4x4. The higher weight of the D-max/Allison combo probably just about evens out the difference between the body styles. D-max truck may even be a little lighter.
So...we have two trucks, about the same weight, about the same displacement, but the gasser running half the boost and lower compression makes quite a bit more power and runs a lot faster. That's my question...why? Is it that the gassers run higher RPM? I was shifting around 5500 RPM, so it's not like it was revving to the moon. Cam profiles? Better breathing? Is there more potential energy in a shot of gas/meth/air than there is in a shot of diesel/air?
My old truck was a 408ci (about 6.7L), turbocharged, about 9.4:1 compression, and I ran it about 16-18 psi, with meth injection. It dynoed 575/640 at 14psi, never dynoed it at higher boost but ran low 11's at 120mph at the higher boost level in the 1/4.
D-max is 6.6L, runs about 30 psi, 17.5:1 compression. I haven't dynoed it but it's run a low 13 at 102 mph in the 1/4.
Both trucks weigh about the same. Gasser was a 2001 4x4 ECSB, this one is a 99 RCSB 4x4. The higher weight of the D-max/Allison combo probably just about evens out the difference between the body styles. D-max truck may even be a little lighter.
So...we have two trucks, about the same weight, about the same displacement, but the gasser running half the boost and lower compression makes quite a bit more power and runs a lot faster. That's my question...why? Is it that the gassers run higher RPM? I was shifting around 5500 RPM, so it's not like it was revving to the moon. Cam profiles? Better breathing? Is there more potential energy in a shot of gas/meth/air than there is in a shot of diesel/air?