Hey all, you might have seen my first build thread. I took a stock Typhon 6s, upgraded it to a TLR version through Jenny's RC and eventually went 103MPH on Stock Electronics. Well that car has developed so far that I have the parts to build 2 cars. So I am going to start 2 new build threads. A GT build and an Offroad build. This will be the GT thread and the thread I post most of my research as I learn to build better cars. I will be comparing the weight of parts along with giving "Slop" and "true" ratings for the parts I have access to. I will use a combination of stock plastic stuff mixed with aluminum and titanium from Scorched RC, Hot Racing and a few others.
The GT build has 2 goals. The first is to get it into the record books. I hope to hit 120mph with stock electronics. The fastest I have seen to date is 116 and there are those who challenge his claim. After I achieve my top speed goals I want to slow it back down and take advantage of the SWB part for some on road racing even if its just with friends. So I have a very loose rulebook to build by.
Last night the tear down of both Arrma cars began. I discovered I have 5 stock plastic bulkheads, 2 Hot Racing bulkheads and 2 Scorched RC bulkheads. All 3 bulkheads use different pinion bearings, however the carrier bearings are the same. I weighed all the bulkheads with their pinion bearings and associated hardware for mounting the sway bar only. I felt this was the best way to get an apple to apples comparison.
The lightest Arrma bulkhead came in at 69.9g and since I have 5 I weighted them all with the heaviest coming in a full 1.9g heavier. Compared to other parts I weighted this is a huge variance which should be expected with plastics. The Hot Racing and Scorched RC both cam in with less than .3g of variance from one piece to the next. I was shocked to see the Hot racing units only weighed 79.8g with the Scorched RC bulkheads showing their strength at 97.3g. You might be thinking the Hot Racing units are the superior unit at this point but wait there's more!! While the Hot racing units are a full 36g heavier as a pair, the tolerance in the Scorched parts are FAR superior. They are superior in regards to aligning the bearings and the fact they they come with shims so you can adjust for the perfect ring and pinion mesh. This is what I mean by a "true" rating where the "slop" rating has to do with slop between it and connecting parts. I can spin a fully assembled Scorched bulkhead and watch it continue to spin for about 10 seconds because the mesh is perfect. 3-4 seconds is about the most I can get out of the Hot Racing units and the Stock plastic units stop almost immediately. I am sure I could build the stock and Hot Racing units to perform better but there is no way they are going to spin Scorched RC butter smooth.
Next I moved to the differential itself. I only have stock vs the Hot Racing parts to compare here. Also my Hot Racing differentials Were last built for speed running and are full of a thick oil and have never been run so I didn't want to rebuild them for this test. Keep in mind my half assed guesstimate of how much oil I put in one vs the other may not be consistent. The best way to have tested this would have been to clean them then weigh them dry like I did the bulkheads. I rebuilt the stock ones last night and used a half fill of a light oil. Remember that when you see these weights. The stock differentials weigh 86.1g and the Hot Racing units came in barely heavier at 90.5. That 4.4g might very well just be the less fluid.
This should be a no brainer because as expected the aluminum version operates way smoother probably due to the tighter tolerances and less flex that you can achieve with aluminum vs plastic. I will be getting more of these and maybe shopping for some other brands.
So what I have concluded in all this? The plan at this point is to use the Hot Racing Bulkheads on my buggy for the lighter weight but the Scorched RC bulkheads in the GT car for the less resistance. I think the Hot Racing differentials are worth the extra rotating mass in both cars so will be getting more or finding lighter aluminum ones. Still debating spools in the GT car for the speed runs. Does anyone have spool weights with gears and bearings? I am not using all the power I have now with the buggy so I think the little bit of extra resistance in the Hot Racing bulkheads will be worth trading for the lighter weight they have over the Scorched parts.
So that's the story so far. Here are a few photos of what I did last night. Thanks for reading and check out my build post for how I got to this point.
The GT build has 2 goals. The first is to get it into the record books. I hope to hit 120mph with stock electronics. The fastest I have seen to date is 116 and there are those who challenge his claim. After I achieve my top speed goals I want to slow it back down and take advantage of the SWB part for some on road racing even if its just with friends. So I have a very loose rulebook to build by.
Last night the tear down of both Arrma cars began. I discovered I have 5 stock plastic bulkheads, 2 Hot Racing bulkheads and 2 Scorched RC bulkheads. All 3 bulkheads use different pinion bearings, however the carrier bearings are the same. I weighed all the bulkheads with their pinion bearings and associated hardware for mounting the sway bar only. I felt this was the best way to get an apple to apples comparison.
The lightest Arrma bulkhead came in at 69.9g and since I have 5 I weighted them all with the heaviest coming in a full 1.9g heavier. Compared to other parts I weighted this is a huge variance which should be expected with plastics. The Hot Racing and Scorched RC both cam in with less than .3g of variance from one piece to the next. I was shocked to see the Hot racing units only weighed 79.8g with the Scorched RC bulkheads showing their strength at 97.3g. You might be thinking the Hot Racing units are the superior unit at this point but wait there's more!! While the Hot racing units are a full 36g heavier as a pair, the tolerance in the Scorched parts are FAR superior. They are superior in regards to aligning the bearings and the fact they they come with shims so you can adjust for the perfect ring and pinion mesh. This is what I mean by a "true" rating where the "slop" rating has to do with slop between it and connecting parts. I can spin a fully assembled Scorched bulkhead and watch it continue to spin for about 10 seconds because the mesh is perfect. 3-4 seconds is about the most I can get out of the Hot Racing units and the Stock plastic units stop almost immediately. I am sure I could build the stock and Hot Racing units to perform better but there is no way they are going to spin Scorched RC butter smooth.
Next I moved to the differential itself. I only have stock vs the Hot Racing parts to compare here. Also my Hot Racing differentials Were last built for speed running and are full of a thick oil and have never been run so I didn't want to rebuild them for this test. Keep in mind my half assed guesstimate of how much oil I put in one vs the other may not be consistent. The best way to have tested this would have been to clean them then weigh them dry like I did the bulkheads. I rebuilt the stock ones last night and used a half fill of a light oil. Remember that when you see these weights. The stock differentials weigh 86.1g and the Hot Racing units came in barely heavier at 90.5. That 4.4g might very well just be the less fluid.
This should be a no brainer because as expected the aluminum version operates way smoother probably due to the tighter tolerances and less flex that you can achieve with aluminum vs plastic. I will be getting more of these and maybe shopping for some other brands.
So what I have concluded in all this? The plan at this point is to use the Hot Racing Bulkheads on my buggy for the lighter weight but the Scorched RC bulkheads in the GT car for the less resistance. I think the Hot Racing differentials are worth the extra rotating mass in both cars so will be getting more or finding lighter aluminum ones. Still debating spools in the GT car for the speed runs. Does anyone have spool weights with gears and bearings? I am not using all the power I have now with the buggy so I think the little bit of extra resistance in the Hot Racing bulkheads will be worth trading for the lighter weight they have over the Scorched parts.
So that's the story so far. Here are a few photos of what I did last night. Thanks for reading and check out my build post for how I got to this point.
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