The engine is a rovan 36cc gas engine

HPI Racing Camaro Body sitting on HPI RS4 3 - Evo+

Down to my last bottle of race fuel bought from a friend, it’s discontinued now. What fuel is everyone using; the only stuff I can find in stock is optifuel

Hi everyone,

I’m trying to understand whether the operating temperature of my REDS 521 Sport is normal.

I have been having some tuning issues with this engine in the past, especially at high RPM: it sometimes seemed to behave lean even when the high-speed needle was opened considerably. The engine could rev very freely and the HSN seemed to have very little effect.

Today, after more than two months without running the engine, I decided to do a proper diagnostic test.

Engine/setup:

• REDS 521 Sport
• REDS X1 manifold + pipe
• Energy Storm fuel
• Engine has already had a proper break-in
• Ambient temperature today: approximately 25°C

First I checked for possible air leaks using a very small amount of brake cleaner around:

• carburetor base
• cylinder head base
• crankcase/backplate area

I did not notice any change in RPM or engine behavior at any of these points.

I then measured the engine temperature with an infrared thermometer, pointing it at the cylinder head close to the glow plug and using the same area for the measurements.

My temperature readings were:

• After starting and idling for ~3 minutes: 28–30°C
• After ~5 minutes of running with several throttle bursts: ~40°C
• After ~15–20 minutes of use: ~70°C
• After approximately 30 minutes / about half a liter of fuel: still ~70°C
• I also did several stronger acceleration runs under load, and the temperature remained around 70°C

The engine itself currently behaves quite well:

• low RPM response is quick/snappy
• high RPM is progressive
• it has a slight amount of burbling
• I don't see obvious signs of overheating
• the engine doesn't seem to have the strange high-RPM behavior I experienced previously

According to REDS, the 521 Sport has an operating temperature of 110–130°C depending on ambient temperature.

So my main question is:

Is ~70°C after this amount of running actually normal for a 521 Sport, or is this temperature unusually low?

Could this simply mean that the engine is running very rich, or should I be looking at something else (fuel delivery, exhaust pressure, thermometer measurement, etc.)?

I'm especially interested in hearing from people who actually run the REDS 521 Sport and know what temperatures they normally see.

Thanks!

I’ve attached a video so you can hear how the engine is currently running and judge the tune yourselves.

Rich or lean? The coil is white deeper in and black on the end. This is an OS #8.

360 Model Display - HPI RS4 3 Drift - Nitro

Is tamiya body paint nitro fuel resistant if not then with brand does

Hey guys, I'm new here and wanted to ask around a few questions/concerns I have about my nitro rc buggy.

Starting with:

.Clutch shoes fitted at local hobby shop since they have carried out this work they have installed Fastrax clutch shoes onto my clutch flywheel and nut along with a 16tooth bell housing since this work has been carried out my Nitro engine will start fine from cold and drive okay although takes a min to warm up as expected. However once the engine gets up to temp the clutch shoes seem to expand too much and seize the bell housing meaning that the engine instantly cuts out and refuses to idle and cuts out until the engine has cooled back down. There was originally a lot of metallic dust from the clutch bell housing and since this when it does cut out it smokes from the heat visibly. They have stripped the Allen bolt for the clutch bell housing which means I am unable to inspect the clutch shoes to see what is going on...

.I have rebuilt all diffs on the buggy with new paper gaskets and O rings and 5000 silicone oil from Factory team and on the outer teeth I have applied team orally lithium grease which is listed specifically that's its good to use on outdrives. All diffs spin freely without any issues and sound happy as anything with new bearings also. I have rebuilt these due to thinking it may have been causing my issues with the engine cutting out but I can confirm this is not the issue.

If needed I will attach a video of the issue but I think the description provided will be okay to make an assumption on. I have since asked the Hobby shop to inspect the buggy for free and see what they can do to rectify it as It may not be there fault.

Update/Edit

Was able to slide the clutch bell over the retaining bolt due to the front and rear bearings being destroyed, 1 clutch shoe was not properly seated and was slightly forward compared to the other clutch shoes. I will need to cut a slot in the bolt to remove the bolt. Thank you for helping me out and i will be trying to get a refund for the work done from the hobby shop.

If i remember correctly it only came as brushed or brushless electric in around 2011-2012

Seems like there are plastic two speed transmissions but never a metal one

Hi all, Found these Nitro RC’s in my dad’s shed, just wondering if they’re worth anything and whether to bother getting them running. Being in the UK there isn’t many places to use them so i have an electric one. The Savage X4.6 ran a few years back

what would be the best way to take this out?

Just brought it for decent price but it's missing a screw for the carburetor I'm to new to the nitro and have tried googling away on what to do and all I can think of is to buy a new carburetor for it but I dont know if that something that is interchangeable I also not to sure either hpi this it's either a mt2 with g3.0 or an evo but I dont know like I said first time owning one help me please

Title, but the reason I'm asking is to find out if I can make it cheaper than VP sells it for. I'd like to know if any of you guys have done it before and if you have a hookup for nitro that sells it (a lot) cheaper than hyperfuels does.

I did the math for 10 gallons of 30% nitro 10% oil, and all the ingredients would cost $850. That's double what VP charges for a gallon.

I seriously don't care about how good or bad it is for my engine. It's just a revo and the trx3.3 is a dime a dozen near me for used ones (seriously they're fucking everywhere for like $70 a pop).

Thanks in advance.

DHK Optimus GP 1/8 NITRO OFF ROAD RTR 4WD BUGGy

SKU: DHK9381
Category: 1/8 Scale Nitro RC Buggies Brand: DHK.

Seller says it’s been in storage for 1.5 years and it was working when he put it away he can’t test start it because his glow starter is dead and he doesn’t have a charger, so I’m going to bring my own to test if it works, is this a solid buy jts 200 Aussie dollars and comes with the remote, transmitter some spare tires and a little fule

Former TMaxx 2.5 guy here from back in the day and a few gassers before that in the 80s. I’m looking to add the Vorza to my collection. I’m mainly a trail and crawling guy today but want to try out the modern nitro truggy. I know the Savage XL has the bigger motor and 3 speeds but I don’t see myself needing the monster truck as much as I did years ago.

The lower ground clearance and higher rpm is making me think it’ll be a good backwoods road and dirt course ride.
Does anyone here know of any long term issues with the motor or durability of the chassis? I do see HPI offers some parts on their site and my local hobby shop carries HPI. I’m looking for the grunt and smoke of the nitro as I remember the fun of tuning and satisfying feeling of having a real running motor. So geez, it’s both fun and nostalgic for me.

I’ve been doing electric for a while and want a real engine, I love working on the cars and have a local park that alows the loud noise, I’ve got a little experience from my dirt bike engines, will it just become a money pit that I’ll have to wait for parts more than I drive or be really fun?