Need a few tips to tune my Novarossi REX28-8... :)

Nathan.OTN

Member
Messages
13
Hello HPI Savage Community !

I have an issue with my engine and I think it's a bad tuning but I want to hear your advice.

At the moment, my engine has a good top speed but in the low RPM, the engine smokes a lot and has difficulties to raise up his speed. I didn't touch the High-end screw so that it is still to factory settings. I tryied to tighten the Low-end screw on the carburetor. I turned 3/4 clockwise from factory setting. it's better but it is not smooth, there is still a lot of white smoke and the engine is not as reactive as I can see on youtube videos. I unmounted my glow plug. The coil looks good but the round base il black/brown. Regarding all these information, I think my engine runs too rich.

I've had a LRP ZR32 spec 2, but I ran it too lean and I broke it. The piston and the top of the chamber were looking "sanded". Since, I've never touched the High End screw of my new Novarossi.


Here are some details about the engine:
Model: Novarossi REX Legend 28-8
Clutch: HPI 16 tooths
Spur Gear: HPI 52 tooths
Fuel: Labemax 25%

What do you think about this ? Isn't it best to recall factory settings and completely tune the engine ?
 

BrandNewSavvy

Member
Messages
27
I've had a LRP ZR32 spec 2, but I ran it too lean and I broke it. The piston and the top of the chamber were looking "sanded". Since, I've never touched the High End screw of my new Novarossi.
Hi bud,

Can you please elaborate on 'running too lean' and 'breaking it'. I am unaware of this happening (including this 28-8, which I also have). I'm just saying you are 100% the engine is 'broken'? I've been doing this a while and have yet to hear of this...so let's just hope it's a good ol' fashion tuning error. Lean engines will almost always cut out before any real-damage occurs,

Regarding the Nova, its best to have a process for tuning the engine (as opposed with just just turning the low end needle and hope it sounds good? The needles work in unison...and I imagine you just think you ruined your LRP and are gun-shy with the 28-8, but these things like to be told what to do. So they are more durable vs what you might think ,

Back to the LRP, if you truly feel it is broken, I am willing to buy it from you. Can you please PM (or reach me somehow) so we can work out the logistics? A video would be great!

.
 
Last edited:

Nathan.OTN

Member
Messages
13
Hi bud,

Can you please elaborate on 'running too lean' and 'breaking it'. I am unaware of this happening (including this 28-8, which I also have). I'm just saying you are 100% the engine is 'broken'? I've been doing this a while and have yet to hear of this...so let's just hope it's a good ol' fashion tuning error. Lean engines will almost always cut out before any real-damage occurs,

Regarding the Nova, its best to have a process for tuning the engine (as opposed with just just turning the low end needle and hope it sounds good? The needles work in unison...and I imagine you just think you ruined your LRP and are gun-shy with the 28-8, but these things like to be told what to do. So they are more durable vs what you might think ,

Back to the LRP, if you truly feel it is broken, I am willing to buy it from you. Can you please PM (or reach me somehow) so we can work out the logistics? A video would be great!

.
Hello BrandNewSavvy, I sent you a message about the ZR32 which I have thrown away... :( Can you explain a bit about your tuning process ? :) I found this thread wich seems to be excellent: Link HPISavageForum
 

BrandNewSavvy

Member
Messages
27
Hey my man,

I’been caught up but will check our your message and of course will give you my suggestions I’ll also check out the link you posted and address any discrepancies in what I feel you should do. I appreciate patience...but yeah I got you. No worries.
 

BrandNewSavvy

Member
Messages
27
So here are some Nova 28 clips I referenced earlier. These are old but the only other clips I have would be in 1:8 truggy qualifiers/mains...and that's nothing but me crashing every other lap and the sound of 9 other engines screaming their tits off it's hard to tell which engine is which.
Ironically I got the Nova 28 for my Savage, however it was way too much power.
That Savage couldn't handle that Novarossi, It is just too much engine. The scary part is I have some Novarossi .21's (Bonito and Virtus) along with a .25 (That Roma) which will steady *smoke* the 28. Its funny the 28 might win out in Dyno stats, but mocing the vehicle from point A to Point B there are some real evil .21 engines out there. I will put my Spec II Speed up against any engine in the world. It's scary grimy. ugh! [shivers]

 

ez2frag

Member
Messages
15
extremercmods.com

Performance Tuning Guide


3-4 minutes



There are many ways to tune a nitro engine but I figure this is the most simple way to do it. This technique is for a fully broken in engine that is ready for a full performance tune. This tuning procedure will set your needles to where they need to be for optimum performance, the engine will tell you all you need to know.

For this method to work the engine has to be at running temperature (or as close to it as possible) as well as having the standard 1mm gap for the carburetor opening.
High Speed Needle
Pull a full throttle pass a couple of times and listen to what the engine does when you let off the throttle. If the it drops right to idle, the HSN is either good or on the rich side. At this point you can lean the HSN in 1/12 turn increments until the idle seems to hang a little after a full throttle pass. If it starts to idle high after a pass it is just on the lean side of a perfect tune. Back the HSN out 1/12 turn at a time after a wot pass until the engine drops right to idle after a pass. Now your HSN is set.

An explanation to what is happening is simple - if your HSN is too lean, after a full throttle pass when you let off the throttle the engine is still lean causing the idle to hang and idle high until the LSN has a chance to take over and meter the right amount of fuel to bring the idle down to normal running speed (given the LSN is set correctly).

If the opposite happens, after a full throttle pass when you let off the throttle it drops to a good idle right away and then starts to idle back up too high, this is a sign that the LSN is too lean. If it comes off full throttle with a good tune and will drop RPM nicely then the HSN is metering the fuel properly but once it hits idle the LSN being too lean will quickly take over causing the RPM to go back up.
Low Speed Needle
Most of this setting was explained above but there are a few little tricks you can use to make sure the LSN is adjusted perfectly. We all know that you don't tune for temperatures, but a temperature gun is very handy for this part. After some full throttle passes with the engine good and warm, bring it in and let it sit for about 10 seconds. At this point take your temperature gauge and hold it as steady as possible on the head, what you want to see is the temp dropping a degree every 4-5 seconds. You want the temp to drop very slightly at idle because when your off throttle the engine should be cooling, if not, the temps will keep pushing higher during on and off throttle running and will cause temperature issues.

This is how I do it and I have tuned a lot of engines for people, whether bashing or racing. I have seen across the board from beginners to veterans that when they hear the high idle after a pull, the first thing they go for is the LSN when in fact it is the HSN causing the issue. If you have any questions feel to contact me at [email protected] .
 

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