CaptBags

Check your midrange needle. They are funky and, can effect the whole range. make it flush. They also have a tendancy to turn them self out and, even fall out!

ChopperMan33

Thanks for the info guys! I bet it is a mid-range needle problem, I turned it about a full turn and a half in trying to get some more acceleration off the line thinking it was acually the low side needle.

ChopperMan33

Good call on the mid-range needle captbags! I jsut ran a tank trhough it and I am now down to 230-240 was the highest I saw and it was probably getting a little lean towards the end of the tank. My mid-range needle is now flush and it fixed the problem completly Thanks again guys!

ChopperMan33

And as far as what it says in the manual...we all know that you can only take it as a grain of salt. I run my savage motor at over 320 f and it is still going strong after 3 years of pumping gallon after gallon of 30% nitro through it..So when a manual tells me one thing and the opposite is happening you have to stop and think about it logicaly and if the os .25 ran hot why couldn't this motor be the same. However I am running in normal operating range with this hellfire. There was nothing LAZY about my tuning!

ogranadino

Good news about the drop of Temp in your engine.
About the manual, I prefer to trust in that info, if there is any problem you always have the warranty.
You should consider to share your experience with hpi team so the can fix the savage manual.

Rgds
Oscar.

ChopperMan33

yes you are right about the manual. that is why they give it to you with the truck, however there can be things that when the manual was created that maybe HPI were not aware of! HPI does a great job with their manuals and I am not trying to bash or discredit them. I do believe that the hot running .25 motor is a common problem (among the one at my track it is anyway!) so my telling hpi would be futile!

CaptBags

No Way should you be running your big blocks at over 300! I don't care how long it has lasted. If it is that hot it is LEAN and, is not performing up to its best potential! do as u wish but, I never even operate my small blocks that high. 220 - 250 for Bigs and, 250- 280 for Smalls is a good "rule of thumb".

Running that hot not only beats the crap out of the internals but also makes it run "peaky" and, irratic. They will run faster, smoother and, longer if you keep them in optimum ranges!

buffmeadows

That's not necessarily true.
I have a Warhead and their support people said that it is not uncommon that their super-crapper (tigre) engines run in the 300-315 range.

I have called them up several different times to get different support people and different ones have all agreed on these temperatures.

wmff82

tune to smoke!

I use temps for a reference. It has good smoke thoughout the power band fading as it reaches upper rpm levels, then the mill is getting lubricated.

CaptBags

Do as you wish, I'm just trying to help. I don't care what Duratrax techs say = Maybe they know there engines don't make good power and, need to ran at the ragged edge to get power out of them? I do know this - heat is the enemy of ANY engine, heat expands parts and, makes them wear execessivly!

You could be running your lowend way to lean, the high end just rich enuff to get decent smoke in the upper range and, be running over 300* cuz it is WAY off! Now you have your beloeved smoke but the tuning is way off. leaning the bottom this much creates a good bottom end but runs eratic all over (lean). I've seen this many times from newbies and, even average tuners.

I know that i never run any of my engines big or small block, in either of my 15 nitros at 300 or over and they run excellent! Also WMFF82 is correct with the fact that temperature is only a tool for tuning - humidity, outside temp and, a few other factors weigh in but, 300 for a big block is definitly to hot!

If this is the case and, you seem to only get good power while in the 300* range go back over your needles. Try richening the lowend and, leaning the high a little - you may be making up for a lean lowend setting by a slightly rich high or, making up for a rich lowend by having a lean high setting!

wmff82

I also failed to mention that going back to your maufactuers start settings are a good reference point. As i travel to different tracks, I always have my needle settings back to factory and go from there. As mentioned above, altitude and other weather variables play a huge roll in the tunning. For example. the humidity here in memphis is outrageously high. Going somewhere dryer like OKC will have a different affect and retunning is a must.

Kanza

wmff82 is right, it's generally better to tune by the smoke trail from the pipe than to directly rely on the temp gun. Aim for a consistent white mist from the pipe under power and fine tune from there. With that being said, the K4.6 and K4.6 HO are generally low temp engines. While any engine reacts to the environment, with ambient temp, humidity, air pressure and so on affecting performance and head temp, the most I've seen from a well tuned K4.6 is 270 F.

Another thing to keep in mind is the build quality of the HPI engines. Where some brands manufacture tight tolerance engines that like high temps, HPI prefers to release more universal designs that can take general abuse and keep going. This might be getting a bit too technical, but I'll throw it out. The K4.6, Axial.28 and .32, and the Racers Edge .32 are all the same basic design. Their manufacturer uses a high silicone to aluminum content in the pistons, which prevents massive piston expansion at higher temps when compared to other engines. If you let the temps get to high, the engine sleeve will expand too far for the piston to keep up and kill compression. This causes the engine to over rev for few seconds after you let off the gas. If a K4.6 starts doing that, you'll want to richen it up a bit.

ChrisR40

I bought some parts from Killer Hobbies this morning and noticed they are selling off all their Hellfire inventory. Check it out.

http://www.killerhobbies.com/

tommyjames

I can tell you all only one thing. I'll have to spare almost if not ALL of the details due to my loyalties, but it is this. If you are considering a HPI racing vehicle or RTR that you plan to convert into racing shape... Don't hesitate to buy their stuff. I was recently interested in upgrading my new RTR Hellfire to the SS parts and asked if they had a full upgrade kit. Their customer service guy was more than helpfuland supplied me with all the info, etc... ;-) I'd ever need. I have not raced it officially yet, but have installed all but the chassis upgrade so far, and it is very easy to dial in, and with aa few more minor adjustments it'll be completely on rails...

The only thing is the understeer, and I would have to say that comes witha blown out, drier track surface mostly. But some minor adjustment could make all the difference. The 4.6HO motor is very fast and torquey and maybe a slightly larger clutch bell gear would make it have a little more top speed, but only if your local racetrack demands it. And the difference between hitting a couple of MPH faster on a straightaway means nothing compared to how you do through the turns and over the jumps... The best way to drive this truggy has been with finesse so far. After running a couple of tanks through it today, I backed off the throttle a bit, and was surprised to find my lap times become faster and faster. I figured that it being a truggy and all, you would be able to use a lot of throttle to keep it fast, but it isn't the case. If you are smooth, you can pull off professional-speed laps, and the nubz tires work great so far, even when things dry out a bit.

Definitely go with strong servos, and bring along an extra set of suspension arms/pins just in case you clip a wall... Oh, and use some extra locktite on driveshaft set screws... All these little things add up to what every proffessional racer endures, which is minor troubles that create priceless experiences that lead to guaranteed victories.

Just know that HPI will have your back, and compared to with the other vehicles I currently own, like the Mugen MBX5 Prospec, and the Kyosho MP777 SP2, when dealing with the support team you will get 10 times the customer service. When a company goes out of their way to enter the class and create a race-bred vehicle in a very popular class of racing, they will usually bend over backwards to make sure and support their products. And HPI is no exception. I'd say, so far they are the closest thing you can get to being factory sponsored without being a team driver... If you have a problem, just ask. They were kind enough to send me the upgraded metal gears for the SP2 servo that comes in the kit, converting it to a SP3, and lets just say "a few" other parts that will keep me in business no matter what happens on the track... Just be cool and courteous with them, and they will be happy to help out.

If I had my Hellfire stolen today, I'd be ordering another first thing tomorrow. And to say the 4.6HO motor isn't race-worthy, would be saying that you need a motor to win races for you, because it all comes down to the driver. Yeah, you should lose the pullstart eventually, but use it until you get the whole vehicle tuned, and then grab a backplate for it, so it can be used with a starter box. But I wouldn't say dump the engine just yet. plus, I read in wither this forum or another somewhere about a slight case mod that lets the intake port work properly that will increase your power substantially. It just takes a little easy work with a dremel. Shouldn't be difficult. I am not worried about it currently, because this thing runs great. I just want to tune the suspension a little more, but it flies great off of jumps.

Not a lot of diff trouble either, just the grease that they pack into the diff housing seeps out easily at first. Good thing is, that dirt doesn't really get in, so no worries, just clean it off, and it will go away. Can't wait to see what a little diff tuning does to the overall handling too... We'll just have to wait to see...

tommyjames

Maybe what should go in here (this forum) is more race-related tips, that'll really get everyone up to speed producing results that will make tuning easier and help us all acheive places on podiums, where people can't ignore this product as being not only competitive, but a class-leader as a dependable, extremely fast, threat at your local track.

Or maybe we need to create a seperate-racers posting that addresses Hellfire related issues in accordance with tuning experiences and race setups...

fern51588

I was wondering what people think about the Hpi Hellfire or the Team Losi Muggy? Which one is the beter of the 2?

CaptBags

I have a pretty highly modified LST and, the Hellfire. I have also looked at the Muggy pretty closely. In my opinion they are both very capable but, it depends on what you want to do with them. If they are your only 2 choices and, you want to race competitively i would say the Hellfire is the more competent racer. It is lighter, has more tuning options and, is closer to the typical truggy setup. I would choose the muggy if you mostly bash and, occationally race = Although it is more of a truggy design than the LST it is still a little big and, heavy to be as agile as the other truggies.

That said,, if i were to do it all again i'd prolly choose the muggy over the Hellfire since i'm not a full time racer and, bashing is where I have the most fun. the Hellfire needs a few costly upgrades right off the bat where the Muggy needs none. You will need to buy a new radio system with the Hellfire since the stock radio is a 6 channel option junker and, the stock servos are even worse - they strip out and, are way under powered for a truck! The Muggy comes with a nice radio and, more than adequate servos. The Muggy is a much better all around deal! It also has Plenty of support since a lot of upgrades for the LST will fit. I guess i'm still ticked that a year ago i spent $600 on a truggy with a radio worth 50 cents - There were better deals out there but i had to have the new thing!

I'd say the Muggy gives you the best all around deal/choice,,,,, I will say = My Hellfire with a few tweaks, upgrades and, tuning is a force to be reckoned with now on the track!

fasteddie2

I'M A NEW (USED) HELLFIRE OWNER

WHAT UPGRADE WOULD YOU START WITH?

IT TURNS BETTER ONE WAY THAN THE OTHER, ANY HELP?

sandflight

Can someone please advise if the k4.6 motor is different to the K4.6 HO engine.

tommyjames

Yes. The sleeve is different and with a slight case mod, the HO can be much faster

bbmods

i just bought a hellfire ss kit to race next year with my mt that i got. are there any tricks or tips i need to know about.

fasteddie2

what engine and pipe are you running?

hellracer

i just bought and assembled my ss. I've raced it in a regional event and two club nights.. here's what I've learned about the HFSS

1. locktite everything that's metal on metal
2. shrink wrap cvd's and center drive set screws
3. check screws on the a-arms at every heat, they all seem to want to loosen
4. check lash at center diff and clutch bell before and after every heat.
5. double check the plastic shock caps on the bottom part of the shocks (I used teflon tape to fix them from unscrewing themselves)

I've broken:
Aluminum Radio Top Plate broke at a bolt hole point (will warranty it this week)
Front Right A-Arm (bad landing in a heat race)
Battery Cover tab broken off (use a zip tie or screw on battery lid)
one certain screw type is very soft and stripped out the heads real easy using HUDY tools (HPI sending new ones)
the clutch bell screw broke off in my crankshaft on first maintenance interval (one gallon)

Hellfire SS
Sportwerks .26 V2
Dynamite 53MR Tuned Pipe
JR-R-1 Radio; DSM; 9000T for steering; 650Z for throttle
O'Donnell 99 plugs running Rocket Science 30% fuel

ringneck

ive heard alot of the radio trays breaking in that spot and its not the tray itself cause ive seen the carbon ones break in the same spot.

gtr

Any detail pic about the top plate broke ?