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Old 11-26-2009, 09:50 AM
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Default Need some input on the Tamiya Dark Impact

Been racing slash at a local track here in GA, and the guys with the 4x4 buggys haul some arse around the track. It wasnt until I got behind the wheel of a B-44 that i knew I wanted one. So I come to you guys for input on the Dark Impact. I am 16, and have a pinched wallet. So basically is it worth the money to buy an impact? (I wouldnt mind a b-44, but dern 350 bucks is a little over my head)
Ive read up that the Tamyia Durga kit was slightly better than the impact, but i do not quite have enough to afford that. The main advantage I have seen is that the Durga has a better center of gravity, and does not nose dive as much as the impact due to battery placement. This was all comming from people running 4200 nicad/nimh packs. I will be running a small but powerfull 3000mah 2cell lipo, and dont think a impact would nose dive as much. Some general input on the impact would be appreatiated. Thanks for any help fellas
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Old 11-26-2009, 10:09 AM
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I know certain people will disagree with me on here (Chang) but I cannot advise strongly enough against the DF-03 chassis.

The design is pretty good (for the most part), CG excellent, and fun to drive when it works but the garbage ABS plastic they use makes it almost impossible to keep the screws from backing out and it's very fragile.

My friend and I both had one at the same time. He had slightly better luck with his but both are extremely fragile cars. The chassis is the weakest point by far. Next is getting the rear diff not to strip out from the case loosening up.
After 2 chassis snaps in as many races I gave up and sold mine. It was not due to driving. If I didn't perfectly downside the jump it broke either at the bellcrank or right in front of the transmission. My friend got a little more creative and decided to design/build his own custom chassis out of some extremely thick Lexan plastic. I took my SC8 and he took his DF-03 to the skate part a couple months ago and I broke before he did. And when he broke it was his castle motor getting the shaft sheared off. The Tamiya held up and amazed me.

Moral of the story. It is possible to get a tough, good Dark Impact but I think you would be far better off finding a used D4, Losi, or B44 to drive around. Far better design and your LHS is more likely to have parts in stock.

Good luck!
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Old 11-26-2009, 10:57 AM
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Thanks for your input man. I build custom rc rockcrawlers and have tons of friends with laser cutters and delrin mills and lathes and stuff, so a new chassis wouldnt bother me none. Is there any room to reinforce the chasiss with maybe some sheet metal? Maybe make a sheet metal cover for the bottom of the chassis? I could drill and use the same holes as the bottom of the buggy to keep it held together strongly. A buddy of mine had a DI and the only thing he broke was the diff gears. I am getting this for a christmass present, so i am limited on a 200 dollar budget and i will still need to get some electronics. I may take my chances with it, and just try to re-enforce the bolts with some plastic glue or something to keep them nice and tight. I will not be running any kind of brushless setup, so its not going to be crazy fast. I think im a fairly good driver, and running into stuff is very uncommon with my messing around on my home track.

Who makes the D4? Again I appreatiate your input
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Old 11-26-2009, 11:20 AM
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Being a forum based on anecdotic evidence here is mine.

The DI is a good kit, easy to build and drive. It may have reliability issues, but for me this was not the case at all. On the contrary. Or I might have been lucky, take it as you will. I have done with this car more than most others out there, but one thing I didn't do was trying an insane motor in it. The highest I tried was 23 turn brushed and when geared properly it was fast enough to hold up its own with mod cars. With a hotter motor I would imagine a lot of problems with all those gears. Not sure what motors have used those who managed to break the chassis but I didn't manage to break anything on mine and it is probably the car I have treated worst in my entire collection. This is my first (and only buggy) and I bought it on a whim, so no further plans for development or maintenance/upgrading were ever considered. I even took it up my fav rock crawling place, and even climbed a concrete dam all the way to the crown at full blast with jump at the top and landing on the face of the wall, like skateboarders.

And yes, I raced it too (I don't normally race off road) and it has taken the punishment without flinching. Around me, everybody was spannering on their cars for the next race whilst all I did was to change batteries.

Needless to mention, being totally inexperienced in offroad I did my fair share of crashing, cartwheeling or landing the wrong way up or nose first. I thought I had destroyed it for good quite a few times, but to my absolute amezement it just kept running like a beast all the way and it is still in one piece and has no damaged parts except for a scruffy rear wing. I only wish my touring cars were at half that strong. I rarely even bothered to clean the thing or do any maintenance on it and it's still going strong.

Out of the box problems.

Replace kit screws with socket head screws and you won't have problems with them backing out. No need to use loctite or any such stuff, and it will be easier to work on it later. I used however loctite and spring washers for the gear cover screws as they go in aluminium and have little thread to hang on to. None ever came out on their own volition. I drilled and tapped another screw hole for the gearcover just below the driveshaft as with just two screws I didn't think the seal was good enough. I used a light dab silicone grease around the cover to make sure dust is trapped if it gets in at all. Now I don't even have to take the cover off for maintenance, I just wipe the dust off when I feel like it (not very often) and that's it.

Another problem you might have is the steering arm brushing against the shaft. Easily fixed shaving the arm lightly.

Brushless motors might take a bit of fiddling to get in too. I had to use a spacer on my Hacker 17.5 (I don't like hacking chassies) to allow it to mate properly the plate. A very light sanding of the chassis ribs in the motor well was just for some extra insurance.

The gearing this motor needs (i.e. the huge pinion) is impossible to accomodate with the Tamiya gear cover so I had to make my own custom gear cover, a fiddly job but with great results. I can now use pinions up to 50 teeth (48 pitch).

I changed to .48 pitch gears too just so I don't have to scour the web for Tamiya pitch gears as I already had a vast selection of gears/pinions. The modification is rather simple, but you need either to find a spur holder that fits or make your own. I used a holder from an older HPI car which was a direct fit after I shaved a little bit off the inside (neck) and re-cut the pin slot with a hacksaw.

LIPO batteries will fit but only if they're the "stick" type or low capacity hard case. I use Orion 3800 with corally plugs on the wires which is not the best but works and again I refused to hack the chassis, instead soldering the ESC plugs to completely flattened wires (I put some solder on the ends, flattened them in a vice and then soldered them to the plugs). Batteries with wires on them might work better.

There is limited space for electronics. I use an LRP ESC with fan and I had to put it vertically, with tape on the side of the battery case wall. I cut a small opening in the side of the shell and covered it with a fine mesh to stop dirt ingress. Never had any problems. I had to route the wiring around carefully and double check nothing was in the way of the shaft which can be a problem with the very limited space available under the shell.

That went on the left side, with the receiver and trasnponder ont he right. Having a larger Spektrum receiver I had almost nowhere to put the transponder. I ended up using double sided tape and put it on the side of the steering servo.

About the rear diff I can say it is still smooth and pulling hard after all these years and has never been rebuilt. Likewise the front.

One upgrade you have to be prepared for (and the only one I have done) is to get front universals, otherwise you might go through dogbones and outdrives quite quickly if not lose them around and get stranded in race.

Apart from that, I have made a front suspension hingepin brace out of FRP circuit board, and it was probably worth it.

I don't use any one-way or slipper clutch so can't say anything about that. Perhaps it could improve the car but for my off road skill I am quite happy as it is, and I was on pace, finished somehwere in the top half of the field, above racers with more expereince and expensive machinnery, so all in all good fun and I was quite happy with the results considering the next to no investment of time and money in the car. The only thing in need of change is the rear wing which has a few scars on it from aformentioned mislandings.

I think if you're on a budget this car has the potential to satisfy you. Take car when you put it together and it will go very well. Using Lipo is going to upset the balance a bit (they are 200grams lighter) but my solution was to just stick a strip of lead to the battery cover, right under the battery (my batteries have dimpled bottoms, so the strip goes nicely underneath). This basically keeps everything as intended. I suppose you could play with weight distribution a bit but again, this was beyond my level of tuning interest.

One advice I can seriously invite you to consider is choosing the tires. These are going to make a world of difference to the car. The kit tires are good on grass and even then just marginally. For bashing they're great and they don't wear down even when run on tarmac.

Wheels are going to be a problem because Tamiya wheels are a non standard size (proper off road standard tires fit on them but with a bit of discrepancy and I don't like that) and they use a hex drive which is not very popular for off road. They are around (Kyosho makes some for their ZX5 and there are others too) but you need to ask. I ended up buying some Thunder Tiger wheels I didn't know existed beforehand and they're very good. For tires, I have been recommended Pro Line and found them easily and cheaply.
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Old 11-26-2009, 11:25 AM
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I own at DI and I enjoy the car. It handles well with some hop-ups, but is not the most durable racer. As mentioned already, the chassis is a little weak. If your track is smooth and flowing, you would be OK. Large jumps are harder on the car. The stock shocks are not good. Motor cooling is inadequate at best. Gearing can also be a problem due to lack of space. The most common part I have broken is also the hardest part to get replacements for. It is also the biggest pain to replace as it required you to half dismantle the car. I have spent about $250 adding parts and replacing parts on mine. I do like the way it drives and jumps now, but every time I jump it, I fear the breakage of the rear diff case and I am not spending $20 again to replace a $3 piece. You have to get the entire parts tree and the only place I can find it is Jason's store on ebay for $10 plus $10 shipping.

I would recommend getting a used B44, Hot Bodies D4, or Kyosho ZX-5. Probably in that order. There are some B44 rollers going for less that two bills on ebay right now.

If you are a casual racer and are not hard on the car, the DI will be OK. You will outgrow it fast if you get into racing and you will get tired of trying to keep it going.

Good luck
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Old 11-26-2009, 11:56 AM
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Wow you guys are awesome! I cant thank you enough! I beleive I will be getting a Dark Impact. I just recently applied at my local hobbytown USA, and they have a pretty nice availability of parts. Also my crawling sponsor has a few distributors, towerhobbies being one of them, so Im not too worried about breaking small things. I am not going to race this thing that often, I will mess around on my small track at home that has nothing but a foot and a half tall jump with good flowing lips and some good landings. Again I thank you guys for your input, you really know your stuff! I will post up in this thread my progress with my DI, and may even do a build thread if im that bored
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Old 11-26-2009, 04:16 PM
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Good luck with the DI. I really have gotten a lot of enjoyment out of mine. There is a huge aftermarket support from 3racing for the chassis. Some good stuff. If you ever see the parts tree that has the rear diff case that the rear tower mounts to, buy it. That is the only thing that is really hard to find. Tower does not carry it. Don't know why not? Like I said before, Jason's store on ebay does have it, but buy in bulk to save shipping and be prepared to wait for two weeks.

I do recommend the slipper clutch as a necessity. If you are jumping at all, it will save your gears. You can also easily switch to AE spurs if you have access to a body reamer. That way you can use 48 pitch spurs and pinions which are by far more common. Tamiya uses a .5 module spur/pinion. No problem with them other than a lack of availability in choices on sizes. Pretty much stuck with the stock one unless you can score a .5 pinion set that occasionally float around on ebay.

Hope you enjoy and post if you have any questions.
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Old 11-26-2009, 04:29 PM
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Originally Posted by Neu_Racer
I know certain people will disagree with me on here (Chang) but I cannot advise strongly enough against the DF-03 chassis.
Everyone is entitled to their opinions, I totally agree with anyone that isn't ready to do some DIY upgrades and hop it up to the point that it costs in excess of TRF511s...

For me, the DF-03 wasn't really meant to be raced with, but it was just a curiousity, of how a chassis with a 2wd layout but with 4wd mechanics would work.

My only gripe with the chassis right now as it is configured in my ride is more droop. I was too conservative with the spacers inside the shocks (as to not break and snap the outdrives) that I put too much and took away too much droop.

I'm in the process of removing some of the spacers inside the shocks (messy stuff, I hate shock oil!) to get more droop back...

This buggy is excellent if you have the stomache and patience to work at it...

The thing is, I was fortunate to not experience about 50% of the problems with this car because I started with the "MS" kit.

The rest of the stuff, is common throughout as Neu, Niznai, and many others have stated... However, a lot of DF-03 owners have worked these issues out, with the exception of TA-Mark, who seems to have a bad streak of the main shaft gear that connects to the spur...

I've put a Castle CM36 4600Kv through this thing, and I've currently have the 380-sized 4300Kv Hobbywing in it...

Here's some pics of my ride in the FS-section if you want to get an idea of just how much work this thing takes:


http://www.rctech.net/forum/r-c-item...cers-only.html

All in all, it is a good kit. Had Tamiya put about another 10% more effort and time, this thing probably would've contended with the 501x (which I suspect wasn't what Tamiya wanted, sales and marketing-wise).

Some things that CANNOT be rectified with hopups and parts and DIY goodies:

1) Suspension link geometry - Although there are tons of different holes for the suspension links, there's only one pair that can be used, since other locations would make the turnbuckles hit the front C-hubs. Like-wise on the rear

2) Material - You either choose cheap aluminum (yeah, 3-racing, and GPM are all junk material) or Tamiya's weirdo brittle plastic. The suspension arms seems to be made from a different grade though.

3) Outdrives - Not sure if this is a constant theme for Tamiyas, but their outdrives lack the hardness that AE and Losi seems to have. My B44 predates the DF-03 by a full year, and the outdrives are still original and has not grooved up yet...

That's about it, of course, this is AFTER you do many of the hopups that is mentioned in the FS thread...
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Old 11-26-2009, 07:37 PM
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Originally Posted by ColbySC10
Wow you guys are awesome! I cant thank you enough! I beleive I will be getting a Dark Impact. I just recently applied at my local hobbytown USA, and they have a pretty nice availability of parts. Also my crawling sponsor has a few distributors, towerhobbies being one of them, so Im not too worried about breaking small things. I am not going to race this thing that often, I will mess around on my small track at home that has nothing but a foot and a half tall jump with good flowing lips and some good landings. Again I thank you guys for your input, you really know your stuff! I will post up in this thread my progress with my DI, and may even do a build thread if im that bored

Come to think of it, I remember a friend with much more experience in off road told me some time ago the Kyosho ZX-5 RTR was the best value for money for entry level cars. That one is actually based on a champion off road buggy and you can upgrade it if you want to the level of its race bred brother (with the equivalent expense). But one point a lot of people make is that the RTR kit is a lot more durable than the race car because it uses soft plastics in the suspension so there's litle to break. I have witnessed this at the track myself when one of my friends who was running a ZX5 SP broke his shock tower on a landing and just changed it for the plastic item form his RTR kit. No problems since.

A lot of other racers prefer to "downgrade" suspension parts on their machines just to keep them reliable (for instance BMax4 cars from Yokomo are raced with plastic rather than graphite suspesnion arms), there must be something in it.
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Old 11-26-2009, 10:16 PM
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Again, I must say you guys sure know your stuff!!! I cant beleive how much info ive received in just 1 day about this buggy. Basically the reason I want the DI is its cheap, I get to build it (which I have never gotten the chance to do) and its on the smaller side. I will just be running a 21t or something with a LRP esc from my rc10t3 with a pretty juicy 3000mah 2cell lipo. Im not looking for any kind of crazy racing machine, but after its got good hardware on it i will put in my awesome 10t motor, and beat on it some then. This is more just to get me going in the 4wd, rather than to compete and win with. I plan on getting this for christmass, but my mom will take me with her when she goes to the LHS to get it, and I will pick up a good 3mm hardware kit to replace all the nuts and bolts on the buggy, and do that little drill and tap mod on the gear cover to hold that down, and then i will upgrade as i get some money.
Again thank you guys so much for your info, I will post back up in this thread when i get going with it!!!

Last edited by ColbySC10; 11-26-2009 at 10:35 PM.
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Old 11-26-2009, 11:19 PM
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I had mentioned that with the improvement of the lexan chassis my friend made his DI lasted longer than my SC8 when hard bashing and the SC8 was one of the most durable trucks I have ever owned.

If you are one of those guys who enjoys working on and fabricating your car more than driving it, the DI may be for you. However, I am not one of those guys so that is my gripe. I also was running a 4600kv motor compared to the stock and super stock motors others here ran.

There are lots of hopups but Tamiya just does so many things differently (gear pitch, materials, layout, parts trees instead of individual ones etc) that it makes it kind of a pain to use. But they are able to be toughened up with enough cash but why not buy a better kit with that money instead?

Good luck with your car and I truly hope you don't regret it. Keep us posted.
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Old 11-27-2009, 01:02 AM
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Originally Posted by ColbySC10

[...]

but after its got good hardware on it i will put in my awesome 10t motor, and beat on it some then.

[...]

With that motor you're never going to have any traction, so it's pointless. The only situation where it might work is indoors on carpet. I have seen a lot of racing in mod here (hard clay track) and they just can't use any of that power. They have so much wheelspin, they have to fight the car to keep it on the track (pretty much like a 2WD buggy). By the time they had some speed and the tires start to grip, the straight was over and they had to turn into a hairpin. Fun for the spectators!
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Old 11-27-2009, 01:32 AM
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If you do decide to go with the DF-03, here's a thread on it:

http://www.rctech.net/forum/electric...f-03-type.html

Lots of good info in there, I welcome you to read through it to get to know the buggy as many of the participants in there did...

Also, just an observation, I have seen B44 rollers go for as low as $150 in the FS section, just a suggestion...
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Old 11-29-2009, 05:09 PM
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hey guys, i actually am about to have a Bj4 on the way from a member on here. So when that comes, I will post a thread, and link to it from here. Thanks again for trying to help out!
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