I basically built an RS4 3 18ss from an Ebay purchase but I am running a Picco XP .15 and a 68 Camaro Body. I am currently using a 19/45 1st gear and 23/41 2nd gear combo. Using my new GPS for the first time the best I could get out of it was 48.3mph using 20% nitro. The only tuning I did was on the needle. I am hoping to get mid 50's out of this combo. I realize the body is a brick so I am considering making a change. Anybody have an accurate top speed of their HPI RS4 that I can compare to? The chassis is mostly stock with a hardened rear final gear set. I am also considering going to CVD's. I realize they would be more efficent and durable but are they worth any mph on the top end? I am just curious on what other people are getting out of their HPI RS4's. Maybe I just need to find a longer parking lot...
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HPI RS4 3 Comparison
- Thread starter ToRed64
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joneser4u
Hardcore RCTalk User
i get those speeds out of a stock gear rs4 3 with a .15fe(os10e carb) ?
i get 60+ out of my os.15cvrx rs4 3.(this car is far from stock, engine is even modded)
better bearings,cvds through out will help alot.I'm sure that body is plowing alot of air also, so it isnt helping.(less friction = more speed)
is the engine broke in completely? was it broke in properly? do you know your temps? a simple tune could help drasticlly.
i get 60+ out of my os.15cvrx rs4 3.(this car is far from stock, engine is even modded)
better bearings,cvds through out will help alot.I'm sure that body is plowing alot of air also, so it isnt helping.(less friction = more speed)
is the engine broke in completely? was it broke in properly? do you know your temps? a simple tune could help drasticlly.
- Thread starter
- #3
What Gear?
What gear ratio combo are you running to get that top end? My motor is broke in completely and was done propertly. The tune on the motor is close to being right on but it acts like it wants another gear. I am going to adjust the shift point to bring it into high gear a little sooner. Then I am going to make a small change on the gear set. I am curious to see how these changes will affect top end. I really think I need to go to smaller spur gears or bigger pinions because the motor seems to pull the current gear set very well. As a baseline though I am going to go up a few teeth on the spur gears to see how it responds.
What gear ratio combo are you running to get that top end? My motor is broke in completely and was done propertly. The tune on the motor is close to being right on but it acts like it wants another gear. I am going to adjust the shift point to bring it into high gear a little sooner. Then I am going to make a small change on the gear set. I am curious to see how these changes will affect top end. I really think I need to go to smaller spur gears or bigger pinions because the motor seems to pull the current gear set very well. As a baseline though I am going to go up a few teeth on the spur gears to see how it responds.
joneser4u
Hardcore RCTalk User
first gear is stock, second is the red 23t pinion with a 41t spur. its a wide ratio so you need pretty good power or it will bog when it shifts. its probably the best mod for speed I've done for the car.
thats gonna slow you down?
thats gonna slow you down?
Last edited:
- Thread starter
- #5
Thanks
That is the same second gear setup I am currently running. I realize going to a larger spur gear will probably slow it down unless the current setup is too much gear. I am curious to see if the motor will maybe turn more RPM which could bring more speed with the different gear set. Eventually I will also try a smaller 39t spur gear but I have to order it. Thanks again for the reply...
That is the same second gear setup I am currently running. I realize going to a larger spur gear will probably slow it down unless the current setup is too much gear. I am curious to see if the motor will maybe turn more RPM which could bring more speed with the different gear set. Eventually I will also try a smaller 39t spur gear but I have to order it. Thanks again for the reply...
