Posted by
Arup.Chowdhury
I currently own the VFJ Jonga having purchased it directly from the factory in 97. It has the HINO engine. As per the BHP figures, the original Nissan in line 6 developed 145bhp on crank and not the wheel as per the original Nissan manual. The VFJ OTOH develops 110bhp in its declawed non turbo engine develops 110bhp on the wheels and also close to 28kg/m of torque at a whopping 990 RPM. The original Nissan engine would roughly develop around 95bhp if measured on wheels with the Hitachi carb. The HINO engine pulverizes the original 3 speed due to its higher torque and output, one of the reasons VFJ has to remove the turbo and reduce the bhp from 138 to 110. I have gone through 3 original gear boxes so I know the predicament of this quite well. The last gearbox is running well due to my extra care of not really pushing the vehicle. Otherwise with the Hino or the original engine its a phenomenal off road vehicle coming quite close to my Gurkha on its off road abilities except the Gurha has even more clearance and the built in diff locks give it an undue advantage.
Dr. Arup Roy Chowdhury Ph.D
Hi guys,
And thanks for the welcome, Sabareesh. To tell you the truth, i am not so much into SUV's(not the modern ones), but as far as offroaders go, i think i can qualify as a freek. And the jonga, well, its my first love. I currently own a Boleor(soon upgrading to a 4x4 Di bolero), a 65 willys petrol and a 72 petrol mahindra jeep(have a 84 rd350 and a 57 bullet too, but thats another thing). I have bought a Jonga, and right now i really cannot decide if i would keep it with the petrol motor or a bombed cummins. I say that because i managed to get myself a lot of stock spares( brand new hitachi carb, original water-proof distributer, and entire drivetrain component set). Either ways, it would get a set of 33 offroad wheels and a nissan 1 ton gearbox(with the pto winch) mated to a atlas transfercase.(i am working on the diff-locks for the stock axles right now).
Arup, may i correct you here. As you can understand, back in the day they never calculated figures at the wheel, it was just the crank, thus the Patrols rating, and i seriously doubt VFJ would even have a dyno to calculate wheel power figures, so it most probably is crank power(and thats what truck motors are calculated in even today). Still it can smash the stock tranny because it produces its max torque at right about idle, and at that point, since the vehicle is stationary, it causes the max stess on drivetrain components, things can go kaput very soon. Secondly if the Hino produces 110hp@3200rpm that means its actually producing 25kgm torque@3200rpm. Since the max torque is 28kgm@1000rpm(therefore dropping only 3kgm torque over 2200rpm), these figures look highly unlikely. I am saying this because the most efficiently these motors(low end torque truck engines) can produce power is till 2500rpm and 3200 is really stretching it as much as you can. And droping just 3kgm of torque over the rpms is amasing efficiency, that absolutely no engine(even todays standard) can match, and that too for a non-turbo motor, which is supposed to be even less efficient(it draws less air at higher rpms, but incase of the turbo its forced-fed). Even the cummins 4bt which is a more modern motor(but the same displacement) drops 4.3kgm over 1500rpm, and that too with the turbo. Take a look at the Ashok leyland hino W04D(same motor as in the Jonga), and it produces 87Hp@2800 and 26kgm@1800(which means its lossing 3.5kgm over just 1000rpm, but thats extremely efficient too, and for the same engine), and adding a higher rpm spring or a ligher fuel pump weight(like it was done in case of the jonga), would only increase the dropped figures, but increase hp levels as rpms are increased.
As for the Jonga stock petrol motor, well, it can never match the torque figures of diesel, but
