So I was thinking, and with 10,000 of these Jeeps made, they say 420 hp right. Now are all the hemi engines tested? Do they all put out exactly 420 hp? how are they rated? Why does my stock Jeep run a 12.99 stock vs some that run 13.4? What could the difference in HP be?? Any ideas about this one boys?

There are slight variables between model year in the most updated tuning version from the factory.

Track-to-track variables are huge... some guys run in high DA, others in low DA... there's no consistency unless you take identical trucks, with identical mileage, that have been explosed to identical conditions throughout their lifespans, and race them back to back at identical race-weights, in the same lane, with the same drivers, using the same launch techniques.

None of them put out 420hp. The 6.1 Hemi is underrated. Dyno testing has shown that stockers generally make between 450 and 465hp.

None of them put out 420hp. The 6.1 Hemi is underrated. Dyno testing has shown that stockers generally make between 450 and 465hp.

That was what i was told also i went to a dyno shop he did a stock 6.1 and it put out 462 hp at the flywheel and 465 tq

Chrysler says the engines are either 2% over or under the 420 hp . So there either a max of 428.4 hp or a min of 411.6 hp.

so what is it? 450 or 411? 411 seems pretty low for these things.

Chrysler says the engines are either 2% over or under the 420 hp . So there either a max of 428.4 hp or a min of 411.6 hp.

i dont think it is 2% of 420... maybe 2% of X (420 being the lowest)...

remember the cobra lawsuits... you NEVER go under advertised HP... thats why 90% of cars are underrated.... just like gas mileage... how many of these really get 14mpg on the interstate if you TRY...

no doubt are they underrated.... ive seen and read these rigs putting down 390 at the wheels... now unless they are losing only 7% thru the drive train than they sure are overrated... especially awd.....

I think mike levy is dead on.... factor in at least 15% thru the drivetrain... so if they really are 420 you are going to tell me they are puttin out 357 wheel hp...? dont think... ive seen numbers much higher than than...

so ive always thought 420 was always inaccurate... 450 hp sounds so much cooler also :)

hitting 12's stock is sick... but CLIMATE can really compromise times... very tough to compare 2 vehicles when their times have been recorded at 2 different locations

None of them put out 420hp. The 6.1 Hemi is underrated. Dyno testing has shown that stockers generally make between 450 and 465hp.

I agree - for a 4700 lb vehicle, it pulls like a mother f'er and does NOT feel like 420 hp.

I am too lazy to do it but if you look at other cars power/weight ratios that should tell you if our quarter times are in line. Obviously other things come into play like aerodynamics and gearing, but that should get us pretty close. (Im talking either magazine numbers or the best numbers that way driver, traction, and track conditions are taken out of it, or at least minimized.) For instance, an STI or evo run low to mid 13s stock, what is their power to weight ratio. If better than ours, our trucks are probably underrated, if close to ours, ours are probably right on, unless the STI/Evo are screwed up too they are from japan after all. I think an STI(04-05) is around 3200lbs and 300hp. So thats 10.67 and Jeep is 4800 and 420 which equals 11.43. This would suggest, with my guestimate numbers that Jeep is underrated. Again, someone would have to do more research than just this, but it is an example. But then again there is torque to consider too i guess. HP sells cars but TQ wins races right?

I am too lazy to do it but if you look at other cars power/weight ratios that should tell you if our quarter times are in line. Obviously other things come into play like aerodynamics and gearing, but that should get us pretty close. (Im talking either magazine numbers or the best numbers that way driver, traction, and track conditions are taken out of it, or at least minimized.) For instance, an STI or evo run low to mid 13s stock, what is their power to weight ratio. If better than ours, our trucks are probably underrated, if close to ours, ours are probably right on, unless the STI/Evo are screwed up too they are from japan after all. I think an STI(04-05) is around 3200lbs and 300hp. So thats 10.67 and Jeep is 4800 and 420 which equals 11.43. This would suggest, with my guestimate numbers that Jeep is underrated. Again, someone would have to do more research than just this, but it is an example. But then again there is torque to consider too i guess. HP sells cars but TQ wins races right?


I think its a good thought but I think torque also comes into play

I think its a good thought but I think torque also comes into play

Hence my last two sentences :D

Hence my last two sentences :D

LOL you would be correct, I didnt bother reading the whole thing

Don't forget GEARING. This is the difference that makes this heavy brick run with the other SRT8's at a premium glut factor....

Don't forget GEARING. This is the difference that makes this heavy brick run with the other SRT8's at a premium glut factor....

Hence my 2nd sentence, come on guys focus.:stickpoke: