I have a new .28 promo kit. Any suggestions on carb restrictor size as I want to break this engine in soon. I hear this thing is a beast so I want to tame it down a little and get better run time

probaly a 6 or 6.5

whats a good pipe to run with the grp .21 offroad buggy engine (non-tuned). Im looking to buy my first engine and this one is on sale at amain for $199 which is at the top of my price range. it is a 5 port engine. any help will be appreciated. would any of the jammin jp pipes work ?

Seems as though the Dynamite 053 is the favorite on that engine.

thanks for the advice on which pipe to get. you are the second person on rctech that said the same thing about the grp and dynamite 053 combo. thats what im gonna go with for now. i didnt want to spend too much on the combo since it will be my first nitro build. Ive ran electric for a couple of years but have got a little bored with the brushless and lipo thing. no maintenance is nice when you run 2 or 3 classes but its time for a change. gonna run 1/8 scale nitro for a while, thanks !

The GRP 2053 will give you much better runtime if that's more important to you. It also costs twice what the 053 does.

Any1 ever have there GRP not hold a tune during a race? motor ran fine the first 2 qualifiers and in the 20 min. main the tune was all over the place. one lap it would be fat as heck and then the next would be lean and back-and-forth thru out the race. temp at the end of the race was fine 175Fish, no obvious leakage anywhere on the motor. OS P3, GRP 2053 pipe, nitrotane fuel, motor idles fine, theres really good pinch, and motr has about 3 gallons to the best of my knowledge (bought used). i ran the motor a couple weeks without fault, so I believe it should be something that happen recently. any1 have any suggestions on where to look for the problem first?

there are plenty of places on the track to clear out the motor so i don't know what the deal is...

im still researching the grp engines and will most likely go with the grp .21 non tuned engine because it will be my first engine. I do have some concern though with the difference in price with the grp standard plugs. why so much higher than others ? they are $14.49 at amain.

hard to say ...sounds like an air leak in the fuel system or on the carb ...just my .02

just run od 99-97 plugs or o.s. standard plugs ...the grp plugs are junk ...most every one will tell you the one that came in there motor new didnt work ....dont spend the money on the grp plugs ..but great motors .....contact mark smith at www.powerhousercperformance.com
he has some standard grp's with his race port on them for 260.00 they are great motors and priced right

McCoy MC-9 plugs have been very good to me over may years. My grp likes them too.

I'm thinking the fuel pick up inside the tank may have cracked. Pressure line may have been getting pinched or kinked once in a while or even the fuel line. Could be a plug problem. Pipe stinger getting partialy blocked by the body or something else occasionally. Make sure the carb is tight. Could also be a linkage or servo problem.
Just a few things to check out.

thanks for the input guys. i will be chckn those things next maint. session. the thing that boggles me is the goin fat part. same needle settings, from earlier, and the motor goes fatty on me? really fat, not just a lil. i can understand fuel line leaks, but wouldn't that cause the motor to go lean? when I said lean in my first post, i should have said it was more normal than anything, it was just fast again like normal. probally felt lean cause it was goin way faster than from when i was trying to race with a fat motor (hope that makes sense).

you know now that you say that again ....check the needle o-rings they are probably worn and are self adjusting ...when they get worn out they can allow the needle to adjust itself :nod:

I was with Stipres yesterday, and helped tune it a bit. I have to say that I was boggled also. I have some experience tuning the the GRP since I ran one the majority of last season.

We had it running good during qual's. When it came to the main (even during warm up) it sounded rich going down the straight. Leaned it out (HSN) just before the start, and sounded good the first couple times passing pit lane. The rest of the 20 minutes, it was inconsistent ever pass. I could hear it building up around the track, then by the straight, it would be loaded with fuel, then sound great the next lap or so... then just to hear it building again, then boggy down the straight. After 20 minutes, came in at 178ish. Weird!

All good ideas. He will have to check those things, and seal the engine. It may juts come down to a bad plug or something simple like that. I have had brand new P3's be faulty. We will see.

I had an issue yesterday with my GRP it would run great and then it was like someone flipped the switch to off and it dies. I changed plugs, had a pro help me with the tune change fuel and then even pull the engine and put in another GRP it still did it. I ended up changing the tank and fuel line and the problem went away. I prob should have done this first but the line was new and the tank had maybe a gallon on it. You just never know. As far as inconsistent tune the o-rings in the needles do go bad. I have seen fuel pool up and come out of the HSN because of bad o-rings. I have seen the idle screw change while the engine was idling because of bad o-rings. The o-rings on this engine need to be replaced periodically. When the needle turns too easily after the engine is warm, it's time to change the o-rings. I also seal the carb and back plate just as a precaution, never had a prob with it but don't want to either. I seal up every engine before I even start to break it in. Saves the annoying air leak tune chasing. GRP's are a good engine but the o-rings seem to get hard after 4-5 gal and need to be replaced. Same thing with the o-rings in the FLS pipe. When they are hard the pipe leaks and time to replace them.

The head on the grp .21, (non-tuned version) the silver one, looks alot different than others. It looks like a solid piece of aluminum with just some ridges cut around it. Why is it different than others and is it a big deal as far as cooling ? can it be changed or does it need to be ? sorry for all the questions, Im just trying to learn as much about it as possible before I buy it from amain.

it seems if you have a non tuned version ...you cannot put the tuned (orange head on it) the head on the non tuned is fine and you will save money on glow plugs ....awesome motors tuned or non tuned ....check out www.powerhousercperformance.com ......i believe mark still has some non tuned versions with his race port on them for 260.00 i believe frank l up there runs marks motors ...as do i ...they are awesome and for 60 bucks more than amain ...you will get a motor that will perform as well or better than the tuned version .....

any1 have any ideas... i had my grp out this weekend and i did post that it was runnin rich but still hot. i was gettin passed on the straight and i barley could make some of the jumps, some of them not at all.... i ran my dads 8ight after the races and he has his vspec in that has prob 5 gallons or so on it and that thing had 3x as much power and speed as my grp. im going to switch to a p4 plug and test for air leaks. this motor has maybe 2.5 gallons on it, is there a way to test the tank?

i mean does it have compression ? i mean if you are chasing other probs and tuning to your other issues ..its not out of the realm of possibility that your motor doesnt have good compression ...my buddy tuned to the dreaded AE gas tank issue and his was toast in 4 gallons ...im just sayin ....its possible ....but ya air leaks and stuff in the carb or fuel delivery system can cause you some strange probs ...god forbide you have run the motor at high temps ...then your really toasty :cry:
on a decent tune mine runs in the 160-190 range on temps ..all types of power to spare all across the board ....and for all you tune to temp ding dongs ...no i dont tune to temp ...im just saying thats what it temps on a good tune ...so shut it :nod::ha::lol:

hey guys i am looking at putting tko's in my GRP and was wondering for those who have run them for a while how they are holding up? Thanks!

just put tko's in mine after 1 gallon on the stockies ....hopefully i wont have to answer that question:D i hope they work well ...they should ..they seem to be the best bearings out there ....i would imagine they would hold up better than stock ...tko says they will :sweat:

Hey guys where would I get some orings just in case mine go bad. Mine is still basically ne (just over a half a gallon but I would like to have them just to be sure??

http://www.amainhobbies.com/product_...ducts_id/23847

http://www.amainhobbies.com/product_...ducts_id/23854

What size bearing does the tuned take front & rear?

Rear Crank bearing 14 x 25.4 x 6
http://tkocompetitiondev.com/product...roducts_id=157

Front Crank Bearing 7 x 19 x 6
http://tkocompetitiondev.com/product...roducts_id=156

You CAN put the tuned head on the non tuned motor. All you need is the turbo button head, and the orange head bolts right up.

one thing i have worked out now on these mptors is how important clutch set up is my grp i wasnt happy with the bottom end power leading up to jumps out of corners worked on clutch set up and now has all the power i need motor ran awsome at the national titles :nod:

i hear Mario Rossi has now left grp so the question is what will the motors be like from now once all the grp tuned ones have gone ???????

Curious, what carb insert you guys running in the tuned .21 for truggy.

7mm and tons of power

I am pretty sure they are the same but can anyone confirm if the carb inserts are the same on the non tuned grp as the ones used on the older mr.ninja bo1a's? :cool:

+1 on 7mm

Hey guys I'm thinking about getting a non tuned to run in buggy this year, has anyone run a losi RE11 pipe on a non tuned? Just curious how it would work, I don't really want to buy a new pipe. What carb insert do they come with?

I have not ran the Losi pipe. Im running the JP3 and iut seems to be ok, but might try the Dynomite 053 to see if I get a little more fuel mileage.

My Non-tuned came with a 7.0 insert.

Has anyone tried the 5.5mm restrictor in the .28?

I'm running the 6mm in a tuned 28 with the GRP 2053, a light clutch and 16/50 gearing. The engine is not wild at all. Plenty of snap without being to punchy. On a slick track I may go to a 47t center gear if traction is an issue. Gearing produces really good top end with a very smooth power band.

What are the most popular plugs to use on the tuned engine ?

I know a lot of the GRP guys at my track love the OS P4 plugs. I know they were saying the trapper is off but the P4 seals up good enough and runs great.

With what I have read on the last couple of pages, the GRP 2053 give you better milage but the Dynamite 053 give you more power. Is that correct?