mixedguy

iTrader: (65)

anyone run this motor i just broke this thing in and it runs ok just gets hot and the grp post i have read say its hard to get this thing hot i am running byrons gen2 30% with a ninja grp #6 plug are they the same as the grp #6 plugs could this be my problem are they same plugs also bottom end is soft have leaned it out but still feels soft heard these motors are monsters so if somone could help me bring the monster to life. o and running the grp 2053 pipe and its in a losi 8 buggy thanks

Merciless

Is it fully run in yet? As mine has had over a gallon threw it and I've still got some metal pinch.

That said I didnt feel the packaged pipe in my combo set feels as good as the JP4 does with the motor ............

The bottom end needle setting is VERY important with this motor and seems to bring the motor to life when right.

Mines set at :

HSN 4 1/3 turns out from closed and LSN 5 1/3 turns out from closed with the barrel opened. I'd suggest you try a little richer than though as there pretty on the mark I feel.

Otherwise I just spend some time with it getting the top end right, then lean the bottom a little at a time until you start the feel a lean bog on acceleration and richen it slightly from there.

Mine runs awesome and Sooo smooth, but it doesn't make power like my C6. I still preffer it as a race motor though

Rod

FrankBlack

Im running this engine with 30% and with #6 plug and yes the bottom is "soft" Im goin to try hotter plugs to get more response out of it. Drake runs #5's and Truhe runs #4's. I also agree with Merciless about the lsn, i find you gotta get it just right, too lean and it will flame during / after pitting and too rich and it will load up and do the same, mine seems like there is sweet spot and if you go even a couple hrs on the lsn eachway out of the sweet spot the thing turns into a dog.

Geo Y-Rock

iTrader: (2)

I also experienced the same with the low speed needle. It has to be on the lean side. I leaned the LSN until it started to "ping" a little during idle. Then richened it until the the lean ping stopped. After that, the tuning is all in the top end needle. I came off the track after a seven minute session, (five min. qualifier), and was temping 190 to 200. I'm using a grp 5 plug. Honestly, I couldn't get it to run smooth with the 6. IMO, they shouldn't sell the engine with this plug. It's like buying a new car kit and they give you tires that don't work anywhere.

Steve Walters

iTrader: (1)

Would you guyz say, that GRP are a tough(er) motor to tune, and can be tougher to find that sweet spot depending on the day and the conditions? How are they throughout a day of racing with changing weather? Are they a motor that requires a lot of adjustment from racing day to day at different location too?

I've seen several, but never own/raced one. Looks like a quality mill....

Merciless

Wouldnt say its harder to tune than anything else I've had. Infact Id say it's pretty easy and holds a tune well. The needles are sensitive though. 1/2 a turn will take you from to rich to over lean. Race Tuning with the GRP is simply something you should do slowly leaning in till ur happy with the top then the bottom.

Do it methodicaly and dont try and Guess where the needles need to be, It's an 1/8th of a turn at a time and try it.Then when your really close I move the needle the width of the slot untill i feel its perfect............

GRP's are very well made mills

Rod

FrankBlack

That is spot on, ive found its so SO sensitive to climate conditions, everywhere i go i have to retune it and i have to retune it from daytime to night time conditions, it can be perfect during the day, the moment the climate temp drops the tune changes, the lsn and idle have to be just perfect or you will flame on the line or while pitting, its a pain in the a$$. Alot harder to tune than the old ninjas/boss engines.

Steve Walters

iTrader: (1)

This kind of sounds like my Axe EVO X1 motor. Great performance, but throughout a long racing day, or racing in the evening going late into the night, I'd say I would have to move the needle at least 6 hours total to keep it in its sweet spot. Its very sensitive to the various climate conditions and changes. My V-Spec's on the other hand doesn't really care what its like outside or where, when I'm racing. I don't think I move the HSN 2-3 hours all year long and the LSN 1-2 hours.

I like the looks of the GRP, but also want to see that life span (How many Gallons) guys are typically getting out of them.

tex1

iTrader: (4)

If you are having problems with temp change from day to night then your plug is very boarder line. If you bump the temp up on the plug it will, in most cases and for most engines, solve this problem.
This is why most every OS engine you see out there runs the OS p3 or p4 plugs all the time.
Find you a GRP #4 plug and get back with us.
All of our customers love these engines when they get the right plug in.
TEX

Steve Walters

iTrader: (1)

Very true. The P3 is a big reason for the easy tuning with the V-Spec...

FrankBlack

As for life span, ive got 21 litres on mine now, changed the rod after 15 litres as a precautionary thing, still going strong

strngdze

iTrader: (16)

Frank is exactly right. I run the GRP .28 with a #4 plug using 30%. This mill is extremely sensitive to outside temps. I have had a few flame outs at the worst times because I have forgot to richen up the HSN as the sun goes down and the temps begin to drop.
I’m in no way bashing this engine, but being aware of the tuning sensitivity will save someone purchasing this engine a lot of heartache.
Aside from that, the power delivery from this engine is so smooth and linear. I’m definitely glad I made the purchase.
Mike Truhe has offered some decent insight regarding this engine over at Neobuggy, he has said himself that the engine is extremely sensitive to leaner HSN settings.

mixedguy

iTrader: (65)

only have 3/4 gallon on it thanks for the plug advise yea i had to richen my up through out rave day to was running to lean. will try the #4 and % plugs. so low speed likes it lean? that explans why it was really soft on bottom but really came alive on top thanks for the help

FrankBlack

I wouldnt say the lsn likes to be lean i just think you gotta get it just right, i leaned the lsn quite a bit when i was obsessing over runtime and it would flame out everytime i opened the tank/pitstop, richening it by approx 4 hrs fixed it, then when i richened it approx another 3hrs, the bottom end response would go and would load up and flame on the line, the sweet spot window on the lsn seems to be very tiny from my experience with it running #6 plugs, i too am going to try #4 plugs to see if it helps.

BradSLC

The GRP engines seem to tune a bit different that most mills. If you're lacking bottem end grunt and you have temps over 200, chances are you're way too lean on top and too rich on the bottom.

Here are two posts from the SGrid that explain GRP tuning characteristics in a little more detail:

"Lopez,Here are my findings on the GRP engine so far: 1) The low speed needle affects the majority of the tune. It is very easy to end up w/ a rich bottom end and lean top end. The tale tell sign is temps over 200 and no power. If it is too lean on top, it will over run at the end of the straight. 2) temps usually are around 165-190* in a buggy w/ ambient temp around 80*F The head is very large and can mask the lean top end. 3) I would suggest this: With you current settings, run the car and get it up to atleast 170*F. Bring it in and richen the top out about 3-4 hrs. LEAN the bottom end 5-6 hrs and bring the idle back down. This is an extreme adjustment, but it will let you know if you are going in the right direction. The bottom end response should be drastically better and the motor will make alot more torque. 4) Keep leaning the bottom end and richening the top until the bottom end doesn't get any better, and adjust the idle to its final setting. 5) you will always use the bottom end needle to adjust the power of the motor, only touching the top end needle if it ever runs on. 6) if you feel the motor needs a little more low end grunt, drop down to a GRP #4 plug or even a P3. Hope this helps."

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"I think it is unique to the GRP motor, but may be useful on the MR
series. I have two theories. 1) the head cools the motor down very
quickly and can effect the tune when going into a slower section of
the track. 2) the flow rate of the HSN vs. the LSN. The ratio of
these two is very important to the effectiveness of the needle
adjustments. For some reason, the GRP motor seems to respond more to
the LSN than the HSN. Most people instictively go for the HSN when
looking for the power, but this engine seems to respond more to low
end adjustments to accomplish this. I have been running my GRP promo
kit for about two months and I am very happy with the torque and over
all breadth of the powerband. I would rate it up there w/ some of the
best engines I've ever run and it has been very reliable.

Also, the motor does not make its best power until it has ingested
about a gallon and most of the mechanical pinch is gone. For those of
you just switching to the GRP, I would suggest giving it time and
check out the low end as I described in my previous post. Run time
has been around 11 minutes w/ a 7mm restricter and #4 plug."