I took my R/T today to SS Performance for the dyno test. The best numbers were 171.6 hp at 6,000 rpm. And 185.9 ft-lb torq at 4,300 rpm. The owner at SS said every time the car shifted it lost about 25 to 30 hp. So the graph was up and down between every shift. He said he had never seen such a big change between shifts before. He said the motor seems to be making good hp,but the tranny sucks. He said he has dynoed 300Ms before and they dynoed around 145 to 155 hp. they were no mods but drop in KNs. He said the Mods i did helped about 20hp. He said he heard about a black 300M in the twin citys that has 100hp shot NOS. But he has a least droped the tranny once. He said a big way to save our trannys is no down shifting very hard on auto trannys. Power braking under 3,000 rpms or not at all.
Dyno Numbers
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Those numbers are pretty close to what GR8WHT dyno'd at with only a K&N. There was another guy on the old dodgertclub.com forum that Dyno'd his R/T at less than 5000 miles, and his HP numbers were around 150. So it's hard to say for sure that your mods have actually given you 20hp or not. Someday I'll tell the wife I need to put our car on a dyno machine.
Cehasgr My mods are dual exhaust a dynomax,cone KN,68mm TBI,and smaller front tires P225/45R17 bridgstones. 97 sport platinum. One way around the limiter is to diconnect the throttle position sensor off the TBI. It will run like **** at idle,want to stall. But under full throttle it works great. I did it on my 99 Dakota so i could get good dyno runs and at the track. And when your done just hook it back up. You also are getting 33mpg on the Hwy my R/T about 27mpg.
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578 Posts
So where's the 242 HP? Is DC BSing us and the public? Is the car a 174 HP car and not 242? If the tranny is sucking up the gross HP, when does, or ever, the 242 HP appear?
Is the 240 HP on the GTP only 175 HP as well, or just not 240?
Explain this because if the 3.5 is 242, then the 2.7L 200 HP would be, say, uhhhhhhhhhhhh, 145 HP?
Danny
Capitalcity RT
Remembering the days when 425 HP WAS 425 HP
Is the 240 HP on the GTP only 175 HP as well, or just not 240?
Explain this because if the 3.5 is 242, then the 2.7L 200 HP would be, say, uhhhhhhhhhhhh, 145 HP?
Danny
Capitalcity RT
Remembering the days when 425 HP WAS 425 HP
The trannys are that bad. The soak up alot of power. My 99Dakota was rated 175hp stock and dynoed 115hp. Chrysler auto trannys just dont but the power down. I have read alot of mopar mag storys trucks and cars that were dynoed with auto trannys. they are all the same the auto trannys suck. The 5 speeds were dynoing alot more power with the same size motors. Chrysler did test about a year or two ago couple of mule 300Ms with Daimler 5 speed autos and 6speed stick in Germany. They were said to be able to go 0-60 in 5.5 to 6.0 seconds and 14 seconds 1/4 miles times. The reason giving for not building them was cost and, the cars would be faster then the current Mercedes Benz. They didnt want the a faster better cheaper car in Germany or any were else for that matter. It would cut into their sales of over priced Mercedes. We are just going to have to wait until the 5.7 Hemi comes out.
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18,091 Posts
So what would it take to drop in a better tranny? 
It is normal for all cars to give far lower chassis dyno power than what the engine is rated for. That 375 hp Corvette may only give 320 at the wheels. It is true that DC auto transmissions are less efficient than some other brands. The Dakota R/T autos typically use up 20% of the power the engine delivers at the flywheel. It appears that the Intrepid R/T trans uses up nearly 30%.
Another factor whch you HAVE to consider is the dyno used for the test. Most magazines and experienced tuners have moved to the inertial DynoJet dynos only - the other 'waterbrake' dynos are just too unreliable and are not comparable even to each other. The exact same car could dyno 170 hp on one dyno and 150 hp on another. Don't believe all the dyno numbers you read without knowing the type of dyno. Even a DynoJet can give bad values if it is not operated correctly.
Another factor whch you HAVE to consider is the dyno used for the test. Most magazines and experienced tuners have moved to the inertial DynoJet dynos only - the other 'waterbrake' dynos are just too unreliable and are not comparable even to each other. The exact same car could dyno 170 hp on one dyno and 150 hp on another. Don't believe all the dyno numbers you read without knowing the type of dyno. Even a DynoJet can give bad values if it is not operated correctly.
True the dyno I used was a Dynojet modle 248c. I trust the owner he races professionally. He has 3 or 4 drag cars some of them are low 7 or 8 second cars. He also tunes cars for the Minn Twins and Vikings. Both teams suck big time again this year what else is new.
what else is new. bboucher i read a post today on the 300M site. One of their owners dynoed his car. it dynoed at 163hp. With the little mods we did and got 171 of or better. We are doing great, 300M have 253hp and we have 242hp in our R/T`s that the dodge ad`s say. Our mods are worth about 20hp.What do think about that? R/T`s kick 300M butt
Is $60 bucks an hour a decent rate for use of a dyno? A guy near my work has one and thats what he charges. Just curious what others have paid. I want to dyno the car pre-mods then do some bolt ons etc and see what exact increase is to document each step. Anyone done this????
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