grp and grp ninja plugs are indentical, you can still find the ninja plugs on a few sites, much cheaper then the grp branded plugs, i know on the offroad engines i had much better luck with the os plugs, onroad could be different

Well I don't know about off road motors but most of the Novarossi sponsored onroad drivers were using Ninja plugs at the nats last week. An importer for another brand told me to run Ninja's. JP himself uses Ninja's. Must be something to it for on road. As for off road, maybe GRP Ninja's just aren't hot enough to work as well as a P3.

Jeez.. now i really wish i had purchased the grp motor from that site you guys linked me.. oh well i will for next one..

So i see that couple of you guys say use os plugs.. some say use grp plugs.. do i need to flip an coin???

just buy alot of grp plugs, i had about 3 out of 5 work, could have just been my luck, the os p3 made the engine alot more responsive and easier to tune, and will idle aslong as you want it to

I have not had any issues with the GRP #4 plug...

i have 3 OS p3 plugs left and 2 p4 plugs left.. so i wasnt sure if i should use the GRP since they made it for GRP motors.. and I used to run OS vspec eb mods.. so.. its a big swamp for me.

one thing i noticed about a a few of grp plugs was that they took a few times to work correctly, u would have to fire the engine up a few times before it would start acting correctly like the plug had to be broken in or something, i had a few that lasted a long time and i had a few that would just never work good, could just grab another grp plug and put it in and it would run good then just put the other one back in and it would do the same thing, if you allready have the os plugs it would be crazy to buy the grp ones, i did find the ninja grp 5's for around 8 dollars a piece when they are on sale, but i just would use the os plugs

lol yah i noticed grp plugs are expneisve everywhere else... I will just have to try and see whats up.

There's about 4 of us at my local club all using P4 plugs. Seem to be a little better than the P3 in this engine. They work fine.

12+ run time
 

I am a club racer looking at getting a new motor...been torn between the Ex tech and the GRP. Well a bud of mine has the GRP on a losi8 and got 12:13 on a tank. He is a consistant and competitive racer. He sold me on the GRP

Alright I will try the P4 plugs.. and see whats up.

:( :( Fuel underneath my front bearing! And not even half a gallon through it, Same thing happed with my V-spec that now has a massive leak at the front bearing and unusable. I hope this brand new GRP dosent do the same thing!

Could it be the fuel(same fuel i used for my V-spec) im using? Its not running overly rich just rich enough for break in.

what fule
and how rich
a bearing going to leak if the motor to rich
half gallon that way to much fule for break in 6 tanks and lean it out

The fuel is called massive mods HB444 and is supposed to be one of the best made here in Australia.

Its not at half a gal yet, just did the 7th tank today and was going to tune for performance and give it a good run tomorrow.

This sucks, i wasn't expecting a shotty bearing in under a gallon from a grp.

If you tune the LSN first then when its good tune the HSN do you need to richen the LSN as you lean the HSN or lean the LSN as you richen the HSN. I thought the HSN affects the LS setting.

Also when breaking in do you primarily lean the HSN from tank to tank or do you lean the LSN or both?

i have had alot of engines leak when they are new, during break in usually because they are rich, i have around 4 gallons on mine and no leaks

Ok i leaned it out a bit more and ran another 3 tanks through it and there was little to no leakage this time, hope it stays that way. Now at 10 tanks.

And man, this engine is starting to open up now, it has a never ending top end atm, im scared if i try and let it reach maximum rpm it will go too far and out of range lol.

alright, i noticed it comes with 3 diffeerent ventris, should i run the smallest for better gas milage?

i use the 6.5 and 7mm restrictors, it seemed like the engine is more responsive with the smaller ones, it dosent really seem to take any power away like it should

I am not worried about power, but having less power helps with less wheel spin, which cause the buggy out of control. Its all driving ablitiy. everyone drives differently. i like smooth low power out of corner then high power before hitting jumps and straight ways.

then you might wanna try a 6mm i never tried the one i have in it yet, i feel the same way about power, its only good if u can put it down

Today during break in off a new GRP engine i had some troubles keeping it running under rich conditions with de GRP #5 plug. The outside tempature was high enough so that couldnt be it. I changed to a OS. P3 plug and i finished the break in with no problems at all.

Question is: Is it possible to go back 2 the GRP plugs or wont it seal proper now? (dont ask why i want to change back ;) )

why are you guys having so much trouble with grp plugs? i have owned 5 ninja engines(4-.21's and 1-.28) and the only time i have had trouble with plugs was when my tune was off. i have broken in all of the engines with the supplied #6 or #7 plugs with zero trouble. the cold plugs are a little harder to tune, but they are very tough. currently i'm running 2 ninja .21's and a ninja .28 and all are running the grp #6 plug. i have used 7 plugs total between these engines since january of this year and the plugs i threw away weren't even bad, i just felt like it was time to change based on the amount of fuel put through the engines. i will be trying the grp #4 plugs to see if the tuning window gets bigger like i've heard.

Yes. You can switch back to the GRP plug. But don't keep on changing it often otherwise it won't seal properly.

I wonder how did this one guy made his GRP motor run 12 mintues one tank.. I know you have to do a good tune and setup, just curious because all i have heard was 10 mintue run time.. is it just a bullshit?

And shims? I wonder if i should not put any more shims in or should I?

The extra shims help increase fuel economy at the expense of a little power loss. There are a lot of variables that affect run time. Pipe and driving style probably being very high on the list. Track size and layout are also major factors.

Dont forget that runtime also is based on how u work ur throttle-finger,track conditions, car conditions, use of a fuelfilter etc. And not only by how much u can lean it out...

I am expert racer, even though I am hearing impared. So I was just wondering so i can talk my pit man into the tuning setup. Uhmm maybe I should try put one shim in because I dont like bottom end too much power but at top end.. So I like mild power at bottom end and nice power on top end.

I know about the throttle situation on my finger, I just am new with grp motor and the tuning seems to be alot different than Vspecs that i have been running for 2 years.

This how i tune my engine, and most grp factory guys. You lean out the LSN till it starts pinging. then richen the bottom four hours. The bottom should be set. Then the HSN should be almost flush. You want it just to clear out on the top. Its not a big revving motor. Then when you come in after warm up, it should be around 170. and if it is then its good to go.

Hope this hepls

Yes I've heard this from another factory driver too. But this part with leaning out till it pings is this something you do while on the starter box or on the track? I am assuming that you have the motor warmed up somewhat before doing this.

After breaking in today this is where I'm at: LSN=4.5 out from bottom and HSN=3.5 out from bottom. Am I in the ballpark? Temped out at 205 and still a little sluggish.

what exactly is pinging? thanks

Does anybody run this motor and if so how about some feedback. My local hobby shop has one at a good price and I am considering buying one.

http://www.amainhobbies.com/product_...ducts_id/26092

it should be similar to the standard mr ninja, just with a standard head isntead of turbo head button

if you wanna switch it to a turbo button let me know i have a new turbo button and glow plug for sale from a mrt tuned that i parted out on ebay

JPZ-67 - That engine should be fine. Its just not a "tuned" version. Essentially its not modded from the factory. Which is what most people should be running anyways.. lol

and its good for rookie to sportsmen..

i have the promo kit.. it comes with the factory tuned pipe along with the motor. so it should be a set right?

First off i have to say this engine is running awesome, nearing the 4ltr mark.

But im having major problems with the carb binding with the engine in my 8ight and flexing of the radio tray, which in an 8ight can only mean certain death for a servo.

I've tried adjusting my linkage and carb set-up every which way possible, different length servo arms and all. The funny thing is when the engine is cold and i think i have it set right the carb movement is buttery Smooth and no radio tray flex at all but when it gets any heat into it its a totally different story.

When up to temp it totally binds up, so bad that it wont get past half throttle. I've tried adjusting this thing every way possible, different length servo arms, different carb rotation positions and different ball linkage positions. No matter how good i get it when its cold, once it heats up it binds like hell.

Any ideas?

I love this engine so much that im almost to the point of selling this damn 8ight with its stupid servo set-up and getting a conventional servo tray set-up buggy.

Jonro - Pull your carb apart and inspect your slide. i have a feeling that it has a bur on it where the idle gap is adjusted. I would be lead to believe thats what happened...

This can happen when you adjust the idle without pulling throttle slightly.. Dremel the bur off or use some scotchbrite. Also when you remove the burr dont be afraid chuck up the slide on a drill and run it some while in the carb body. It helps free it up some and may prevent additional sticking.

Some guys have this problem some dont. It seems hit or miss.

Hope that helped...

GRP tune 21 buggy vs OS speed
 

I have the os speed with the mag head in my RC8 and looking for an engine for the RC8T. how are those 2 engine compare?

Thanks