RPaulG87

Irecently purchased a slightly used Hellfire on Ebay for 280$, the guy has already upgraded the front shocks to HPI's Hot Bodys, and added a JR all metal steering servo (it's amazing how well the Hellfire turns now) as well as upgradeing the front A-Arms to Integy Aluminum, he also added the integy center differential (don't really know the benefit that has but yeah), also has the increased durability integy aluminum turn buckles.

Took me around 4-5 minutes to get it running, which considering he hasn't run it in like a year, that's not too bad. Everything seems to work well atsept for a little front wheel-wobble (Ithink Ineed to adjust the camber).

Anyway, my quesiton is what is the vital parts to upgrade on the Hellfire?Iknow every previous R\C I've owned (though none were up to this scale, I've owned the Nitro Rustler, E-maxx, and Savage) none of them are bullet proof off the bat. I've never owned a truggy like this before, so I'm not sure what is the most vital parts to upgrade, Iknow some you want to make right when you get it to avoid one weak part breaking which causes other parts to break, so I was curious of the Hellfires main weaknesses.

My current plan (as things break)is rear aluminum a-arms, rear hot bodys shocks, aluminum chassis braces, and double-strength aluminum shock towers. I've heard a few issues of the Hellfire, mostly with steering, though with the servo the guy installed this thing turns better than anything I've owned in the past. Basically wanting to know what you guys think are the "weak points"of the Hellfire, as well as what the best gearing setup is for it. I'm not sure what this guy did, but Inoticed compared to my E-maxx (of course it's electric so it has more torque off the bat)the Hellfire seems to start off slow, however once the engine winds up, it starts going crazy fast. I was Iguess wanting a more torquey setup?It could just be the used engine, but it seems to have LOTSof high-end speed just not much low-end torque.

Anyway, thanks in advance!Also, Ihave a roll cage that Inabbed on Ebay for 20$ (apparently a very good one just got a deal) soI'll be installing that shortly.

Here is a pic of the Hellfire currently, Ihaven't driven it too much just wanted to make sure everything was in working condition so I zipped around a parking lot.

stussman

So thats the rtr?
The rtr has weak diffs,shock towers, braces, suspension mounts.
I have had 2 rtrs and an ss. The ss is alot stronger than the rtr.
I would upgrade the diffs to the cen gst diffs, They are way way stronger. The rtr pinions are weak as piss. Make sure you shim your diffs.
The k4.6ho has good torque. The front bearing can leak easy and mid range needle can come loose and fall out. But it is an ok easy tune engine.
I have an ss with gst diffs, 7955 servos,badlands and an os28 drag modded which is getting put in tomorrow. I will post picts soon.
The ss is ok for bashing. The rtr will break more often.

RPaulG87

I'm guessing it is the RTR. Could you possibly point me to the cen gst differentials for the Hellfire?I'm guessing they are just drop in, pretty easy?This will mainly just be for I guess "bashing"and "fun"not going to race it.

For the braces, the aluminum (better) ones are cheap, but it seems as if you have to drop the bottom chassis plate to replace them, am Icorrect?

Also, just bought the Integy Purple HDShock towers, I was going to go with HPI'S billet towers, but Ican get two Integy Hds for the price of ONE HPIbillet, and I'm still guessin' the Integy's are around double the strength

stussman

There has been alot of bad comments about the strength of integy products so you will find out if thats true or not.
I got my gst diffs off ebay. The pinion and crown drop straight in the hellfire cups with a little shiming. There are lots of posts on the diffs on this forum so do a search. I would pull your diffs,shim if required, and bash as is. If they start wearing qiuck order the gst diffs.
The plastic braces will do for bashing but the rear one will bend very easily. They should be easy to replace. Id wait to you really need them.
The top chasis plate has a habit of cracking next to the steering servo. No biggy though.
Those tyre will be ok for bashing. They last ok.
Watch out for loose screws and they also strip easy.
What pipe is that?
The HF is very heavy so with the roll cage it will be extra heavy but that engine has good torque so all good.
Overall it looks in good condition. The HF isnt the best truggy but for bashing with a couple of upgrades it will be ok.
Post a vid or more photos.
Enjoy.

RPaulG87

I've heard things about Integy as well, but I can't see how going with their parts could possibly be worse, I think the stock shock tower is 3mm aluminum? Integy is 5mm, so it will be stronger for sure, I know the expensive HPI Billet one is 6mm, installed the roll cage today, I REALLY need a higher weight oil, the car just sinks down now :P. This roll cage seems to be built like a rock, pure steel unlike the other aluminum ones.

Is there anyway to prevent the top chassis from cracking O.o that seems like it'd be an expensive repair since it's aluminum..wouldn't even think aluminum would crack.....Ibelieve the pipe is an upgraded HPI one.

Also is this what Ineed? cgi.ebay.com/CEN-Genesis-Nemesis-GST-7-7-Rear-Differential-Diff_W0QQitemZ330396431900QQcmdZViewItemQQptZRadio _Control_Vehicles
And Ican use that in both front and rear? What about the center? Also what do you mean by shimming? Thanks!


One more thing, you turn off the engine by putting a cloth over the exhaust..dosen't this leave nitro in the engine?Will that nitro hurt if it just sits in there for a week or two?

nitroexpress

IMHO the last thing a vehicle needs is Integy parts, especially arms. Aluminum might add some bling, but in many cases plastic is more durable. GPM is slightly better, but not much. All aluminum is not created equal. Some is cast, some is cnc machined and there are different grades of aluminum. Whenever possible, buy HF SS parts which are tougher than RTR parts. Let EBay be your friend.

http://cgi.ebay.com/HPI-86587-BILLET...item413c9e4f9e

http://cgi.ebay.com/HPI-Racing-86510...item2eaa7838b4

RPaulG87

Ok I'm confused the aluminum chassis you posted above, which you say is from the SS is the same one that is on mine...The only Integy parts I have purchased were the heavy duty aluminum shock towers, because I can get two for the price of almost ONE billet aluminum HPI shock tower. This thing has a few more integy parts that the previous owner installed..the upgraded turn buckles, center diff housing, etc. The billet aluminum shock tower dosent' even seem to be standard on the SS...from what I can tell, the RTR and SS seem to use the same aluminum shock towers...

I don't know what front A-Arms this guy put on, they almost look like billet aluminum, no integy is written on them so I don't believe they are Integy, but they are extremely beefy.

RickyIS300

Rumors says Integy cast parts but according to them, they have billet machined parts http://integyfacts.com/
Nothing bend on my truck yet, so I guess they are okay.

RPaulG87

I emailed the seller on Ebay to cancel if he has HPI's Billet Aluminum mounts. Way I figure it, if you get those shock mounts, then get hpi's billet chassis mounts, your well on your way to bash-proofing a hellfire. Could just be me though.

nitroexpress

Beefy, super stiff arms are not good. You will break hingepins and etc. Plastic will flex and absorb shock, aluminum will not. But aluminum looks flash, so go for it. You'll learn.

nitroexpress

I didn't post a link for a chassis, it was an upper deck. I suppose some RTR and SS parts might be the same, but the main chassis and shock towers are definately different.

RPaulG87

The upper deck you posted is the same as the one Ihave. Why are you saying"You'll learn?" It came with the aluminum a-arms, no need to be all high and mighty, I'm just asking questions.

stussman

The ss shock towers are definately way stronger than the rtr.
The braces on the ss are alloy while the rtr has plastic braces.
The ss has alloy shock caps and the rt plastic.
etc etc
Also to stop your engine pinch the fuel line next to the carb and remember to burn off the fuel left in your engine when you are finished.
I posted a picture of my old ss in the truggy picture post if you want to have a geeze.

RPaulG87

I went to my local hobby town usa and the guys said to leave some nitro in the engine, since it still keeps parts lubed up since nitro formula contains oils, which makes it of course extremely easy to fire up...can't think of a bad reason of leaving it in...

I also noticed today after trying to fill the front "hot body (HR)" shocks that the right one doesn't seem to be working anymore, Iwas switching to 25 due to the weight of the roll cage I need the shocks to snap back quicker, however no matter how Ifill the right shock, or how Iget the air bubbles out (which Ireally can't seem to get out), it gets stiff to the point that the piston will not move up at all quite strange, maybe I'm just fillling it up incorrectly?

Am I also correct going with 25 weight due to the extra weight of the roll cage?

One more thing as well, Ibelieve in a month or so I will upgrade the engine, it seems one of the best (for the price)engines would be the LRPZ .28RSpec 3 engine?Anybody know how hard this is to install in a Hellfire?Or is it just bolt up and run?Thanks!

Also bought 3 HR aluminum chassis brace (rear, front, center) since these are one of the weakest pointsIhear on the Hellfire, and HR shocks for the rear. All three for 17 so not too bad. After this it seems the only really weak points will be the internal differentials. I'm guessing to replace the braces Ihave to completely take off the top chassis\deck?

stussman

Its best not to leave nitro in an engine for any length of time. It will cause rust or can go up the engine. A couple of drops of after run oil helps if it sits for a few days or more.
25 weight oil is fairly low. You probably need 50 or higher so it bounces back. Lower weight it will be softer and sink down.
The bumpstart version lrp will be ok but the pullstart version will not sit correctly due to the pullstart sitting lower than the crankcase. You need washers or similar to lift the pullstart version up slightly higher.
It is hard to get to some of the screws for the braces out. You mite need to remove the fuel tank, diff etc to get to the screws. You probably need the small right angle allen keys to get under the top deck.

RPaulG87

How would nitro in a nitro engine cause rust?That's like saying leaving gasoline in your normal vehicle causes an engine to rust, no matter what there is always a "coat" of nitro, and with nitro cars it's combined with oil to lube up the engine...I can't even imagine someone would design something that uses a fuel source that errodes itselfO.o.

The guy at the LHS said with heavy cars, you want lighter as lighter oil allows the shocks to "bounce back" quicker after jumps, heavier weight bounces back slower, Ihad 35 weight in it when I got it, and it just sunk to the ground, the shocks would not shoot back up, so I can't see going higher helping:-\

And thanks with the help for the braces, it looked a bit hard but hopefully it'll be a one time thing, I'll feel much better with aluminum braces instead of plastic going to an aluminum chassis and aluminum shock towers, imo aluminum and plastic don't mix well, could just be me.

stussman

The fuel attracts moisture in the engine. If you search on this site you will find most experienced users will burn off the excess fuel out of their engine by removing the fuel line to the carb and starting it until it burns off any fuel sitting in the engine and wont start. Alot of users will then add ARO to the engine and spin it over a few times. The ARO lubes the parts and prevents rust etc.
It will depend on what fuel you use to.
When you block the exhaust stinger to stop the engine excess fuel will be left in the engine unless you burn it off.
With the lower weight oil you will bottom out alot easier, especially with the heavy hellfire, especially over jumps. You will also have more chasis roll, better traction. I like heavier oil as i go over jumps.

RPaulG87

That goes against everything I've read...doing that is like pinching the fuel line, which hurts the engine and as it states in every R\C manual, should only be used in emergency situations, why?Because it causes the engine to lean out until it shuts off, nitro fuel is formulated to lubricate the engine, lubricants keep OUT mositure andCOATto prevent rust, how do you figure nitro fuel in a engine is going to attract moisture? Ican't find a single nitro fuel out there that dosen't have lubricants in it that prevent rust and help moving parts, and the more reading I've done, the more after-run oil seems useless unless you are going to let your r\c sit for a year and let everything dry out, otherwise the nitro fuel will lubricate it just fine.

My only thing with heavier weight oil...is that the heavier it is, the harder it is for the piston to spring back to it's orignal position after it's gone down, even more so with a heavy vehicle..@35 mine couldn't even do it right...Icould try a heavier weight oil Iguess...Ijust don't see how that is going to let the piston spring back like lighter weight oil will :-\

nitroexpress

Shock oil weight and spring rate have to be taken into consideration together. Many people use shock springs that are too stiff and then run a shock oil that is too light. Makes the vehicle pop up like popcorn. Takes time find a good setup for a given track. Chassis slap is not necessarily a bad thing. A properly set up vehicle will slap a bit on the largest jumps. That's how you use all the the suspension. So if your chassis bottom is super shiney, your set up is wrong.

RPaulG87

Ihave another set of stiffer springs that would easily keep the car leveled, however I figured it would be better, kinda like you said, to use a light weight oil and the medium weight springs instead of the heavy (medium is what it came with) I'm still trying to find the easiest way to get out the diffs to replace them withGST, and get to the chassis braces without taking out the entire deck..but it looks like you have to.

nitroexpress

There are six different shock springs available, so I'm not sure what "medium" would be. I can tell you that the recommended setup in the manual is pretty far off. You can pretty much forget about using the 4lb and 11lb springs.

BTW, setting ride height is done with the plastic spring preload spacers and not just spring stiffness.

RPaulG87

Idon't have spacers, the front is what is sagging and it's fully adjustable, all the way at "max"in terms of stiffening the spring, just seems the silver springs aren't gonna hold the truck up enough.

stussman

It doesnt hurt the engine. It leans for a second and then dies out before heating up. If you have finished with the engine for the day pull the line off the carb and burn the excess fuel off. The engine starts for a second and all the EXCESS fuel is burnt from the engine. A coating of fuel/oil will still be on the internals. I only use ARO if i let it sit for a week or more. I agree most people have different opinions on whether ARO works or not. I actuallu use auto transmission fluid instead of ARO.
Cranks and crankcases do rust! I have opened numerous engines that have had rust on cranks. If you leave excess fuel in the engine your asking for trouble.

RPaulG87

Iguess my question is how exactly does the rust bit make a difference if there is a coat of nitro left behind, or it's full?Clearly the coat "displaces" mositure and protects, so with the engine being filled with nitro, it should protect even more...

My biggest issue now, is Ican not get air bubbles out of these shocks if my life depended on it, either that or something else is messed up. No matter what Ido, no matter how much air Iget out, when Iput the shock cap back on, Ican NOTpush the piston upward, it's like it has some kind of resistance, yet when no oil is in it, it works perfectly, any ideas?I'm tired of spending an hour on one friggin' shock -.-

stussman

Have you played around with the pistons in the shocks? Maybe the hole in the piston is not letting the oil thru? Ive only ever played with the standard hellfire shocks, not the hot body shocks. Sounds very frustrating . When do you think you are gunna let it rip and chew some juice?