Tuning a LRP.28

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WVNed

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398
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Scott Depot WV
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I put a new LRP .28 in my savage. I can't get it to tune. It runs very rich at idle to partial throttle and very lean ( loses power) at full throttle. It will idle with the LSN closed. I was doing the fuel line pinch and it dies at 7 seconds. I was trying to get it down to 5. It died at 7 seconds and I found I had turned the LSN all the way closed. I opened the LSN back to 3 turns and leaned the HSN enough that it wouldn't die coming off idle. It starts and runs very good to 3/4 throttle then loses power and overheats on full throttle. It has had a quart of fuel through it now.
I used 3.5 turns on both needles as my starting point. The manual says 5.5 turns but the needles fall out when opened that much.

Help
 

GAJ

RCNT Qualifier
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Southern Ontario, Canada
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No expert, but it sounds to me that the HSN is too lean, LSN too rich. Make sure the idle is at least 1 to 2 mm, use the trim on the receiver to open it up a bit until it warms up.
 

WVNed

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Scott Depot WV
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When closing the LSN it never leans out and has the idle increase. It seems to do little or nothing.

Perhaps I should take the carb off and clean it. Maybe it has junk in it.
 

cbaker65

Hardcore RCNT User
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3,405
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Kern county ,Calif.
Reset the needles back to original setting.An if your putting a new engine in an old chassy ,then check the fuel
tank & lines an make sure they aren't clogged or dirty or have air leaks.Those are the signs of failure if he engine
is not responding to any tune.
After that ,then start the retune!...
 

WVNed

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Scott Depot WV
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Running truck. I pulled an LRP .32 to use in an 8ight T and dropped in the .28 to replace it and started breaking it in. Everything went fine until I tried to get it rich enough for the full throttle part. I cleaned the carb today and checked the lines/tank. I set the idle gap and put the needles back to 3.75 turns. I got 3.75 turns here.
https://www.hpisavageforum.com/threads/nitro-engine-factory-settings.11154/
 

cbaker65

Hardcore RCNT User
Messages
3,405
Location
Kern county ,Calif.
Ah ,Sometimes a dirty tank or air leak get people when they add a new engine to their old rides.
It happened to me ,an I blew up a new 8.0 engine.

Did you get it to tune right?
 

cbaker65

Hardcore RCNT User
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3,405
Location
Kern county ,Calif.
Ah ,yes temps may effect the LNS because your suppose to warm the engine up before you do that
setting.
46 % is a low temp .Are you getting the temp up on your engine ?
 

cbaker65

Hardcore RCNT User
Messages
3,405
Location
Kern county ,Calif.
Are temp at night are still down to 45 ,an during the day has been hitting 75.
I'm not sure if 45 is terribly cold for a nitro engine ,maybe a new one.
Also altitude can have an effect,I'm at only a 100 ft ,so that's no problem for me ,however when
me an my b-law took are trucks up past 5000 ft ,Lol ...they wouldn't hit a lic!
 

olds97_lss

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Dekalb, IL
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Well, I've had 4 of those engines so far. Not one of them ran well with:
- ambient temps less than 50F
-- just a real bear to get started when it's below 65-70F outside. I'd put them on the floor of my car with the heat on high to get the head temp up to 80+, then they would fire up and run ok in 45+ ambient temps. I won't run them in cooler weather than that. I reserve my crappy engines for "winter" driving. If I shut it down to move to a different area, I had to warm it back up again, or I'd pull and pull and pull. After the first blister, I tried heating it up like I mentioned, then it fired right up and ran just fine.

- fuel less than 25% nitro
-- will run on 20%, but runs and tunes much easier on 25% nitro and < 12% oil

- plugs that were not medium temp
-- odonnel purple work well for me

- a pipe that is a bit constrictive
-- the HPI polished pipe made it run like crap everywhere in the middle of the RPM range. Could not tune out the burble in the mid-range no matter how hard I tried. I run an LST2 HT pipe on my savage and a THS BB revo pipe on my revo, and whatever OFNA's stock pipe is on their 10 year old buggies.

- a gallon of fuel has been through it
-- after about 3/4-1 gallon, the power really comes on and tune stabilizes very well

Once all those issues are covered, then they run great, run cleanly from idle to WOT, will sit and idle for minutes without loading up to bad and pull hard all the way to WOT. I have 3 currently, sold one to a buddy of mine a long time ago because I was feeling sorry for how bad his dynamite Mach 427 was treating him. I probably have 3-4 gallons through the one in my revo, 4-5 in the one on my buggy. The newest one is in the savage with 2-3 gallons run through it. All 3 still run like a top all day long.

If you only have a quart through it, your barely through the break-in. Just tune it to keep the temps between 220-250 and keep putting fuel in it. Really, at nearly a gallon, all 4 of mine started running at 240F all day long with a clean rip through the entire RPM range and I'd only have to do minimal tune adjustments at the beginning of a day, depending on ambient temps.
 

WVNed

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Scott Depot WV
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Same ol HPI tuned pipe.

I have gotten this thing to run well except for wide open. It's already faster than the .32. I went back to 47/17 for now.
 

olds97_lss

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Yeah, that pipe is hurting you too. That's what I had when I first got it because it worked so well on the engines I had prior to it, OS21RG, XTM 247, SH28, Mach 26SS... the LRP just didn't like it. My first LRP was on my aftershock, so I tried the LST2 pipe (losi high torque tuned) off my buddies LST2 and it worked great. Then after that, I'd just buy that pipe and modify as needed to get it to work vs wasting money on other pipes. At the time, you could snag them off ebay for $20 pretty easily.
 

WVNed

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Scott Depot WV
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I happen to have an LST2. Perhaps a test will be in order.
I dont think I have a headpipe that will work.
 

olds97_lss

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It won't stay on well. To use a "2 piece" header/coupler, I ground down the inside ring so the ziptie could squeeze the coupler enough to hold on. Then again, I use nylon reenforced hose as a coupler... might work ok with a normal coupler. I also have a little L bar under the pipe holding it's weight. I've had the same coupler and header gasket for 2 years. Before the L bracket, I'd tear a coupler and wear out a gasket every few bash sessions. I'm hard on stuff.
 
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