ZR.32 Spec.4 engine in a Hpi savage 21?

Clifffff

Member
Messages
48
Got the LRP 32 today! ๐Ÿ˜ƒ๐Ÿ‘Œ๐Ÿค˜ here is some pics of the engine and accesories. I went with the backplate and rotostart too. Hope i Will get satisfied. ๐Ÿ˜ does anyone know if the rotostart fit with savage 21 without any modds? I'm guessing it goes in the rear so i am mainly thinking about if it goes Free for the suspension?
why didn't you get a picco 28? IMO the LRP engines are not different from SH, HPI etc. they are all manufactured in the same plant in Taiwan. But I really hope the LRP gives you what you are looking for.
 

Clifffff

Member
Messages
48
most people don't know this but LRP 32 shares the exact same crankcase, crankshaft and conrod as SH 28.
 

OnThatPipe

On a vacation
Messages
63
@Sparky, thatโ€™s good to hear. I'm glad you have it controlled. Yeah, I've tried to increase the engagement level, spring down, heavier shoes, heavier flywheel, tails with reduced pre-load, loosened the slipper, etc. (all phases of schemes of an early engagement)

The result is always the same in that instance. The engine stumbles due to the amount of draw in the engine at the low RPM range. Itโ€™s not as bad if I run in low-bite but the draw is still there (only a little further in the range).

Consequently it's a catch-22. I can't tune it when the clutch is engaged too early. So if I get the clutch right (matching the engines RPMs) Otherwise the engine is overloaded. So itโ€™s a choice between it being drivable or being tuned at that level of power.

As noted there are many things I could do to combat it. Iโ€™m confident weight (lack of) is playing a role. I am a weight phreak when it comes to this. so Iโ€™m confident if I armored it up the weight would allow me to engage earlier but I spend a long time getting it light and durable. I could also lower the CG

I'm sure it's another reason I can rock it with that F4.6 I case modded, when using the right torque or mid-range pipe (2090/2013/2053 all do well). Reducing weight adds RPM figuratively speaking.

Finally, regarding length, I know nothing about that XL. I did extend the wheel base a few years ago using the IRC extended chassis but Iโ€™ve since switched due to the inability to access the idle stop on that Nova 24069 carb I like. Anyway, good stuff. It's all about getting the truck to what we want in the end.
 

OnThatPipe

On a vacation
Messages
63
why didn't you get a picco 28? IMO the LRP engines are not different from SH, HPI etc. they are all manufactured in the same plant in Taiwan. But I really hope the LRP gives you what you are looking for.
Very similar in fact.
Picco is a great engine and that 28 is very nice with mid-range 2060 or 2053. Once they drop nuts they will idle for days.
 

olds97_lss

Well-Known Member
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2,180
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Dekalb, IL 60115
why didn't you get a picco 28? IMO the LRP engines are not different from SH, HPI etc. they are all manufactured in the same plant in Taiwan. But I really hope the LRP gives you what you are looking for.
I've heard that quite a few times over the years and after having both a few LRP28's, SH 28's, the LRP's perform a lot better and the pinch lasts far longer. The tune of an LRP is a bit more fussy, guessing the carbs differ, or the porting does, or both. Also guessing the sleeve or piston or both materials aren't the same, giving the LRP's more life.

I've had 3 SH 28's, none of which made it past 5 gallons or so without performance and becoming fussy to tune/hold a tune. I have at least one LRP28S3 though that has 10+ gallons through it and it still runs like a top.
 

Nitroholic

Member
Messages
38
Location
Sweden
Clifffff , i didnt no about the pico engine nor the LRP. I'm a beginner in nitro but learning. I went with this engine because i was advised that this was a engine with much power and that it would fit me savage without to many mods. I hope i Will be satisfied to but with all the replies in this thread I'm having second thoughts. Hope it isnt to big engine.
 

OnThatPipe

On a vacation
Messages
63
Clifffff , i didnt no about the pico engine nor the LRP. I'm a beginner in nitro but learning. I went with this engine because i was advised that this was a engine with much power and that it would fit me savage without to many mods. I hope i Will be satisfied to but with all the replies in this thread I'm having second thoughts. Hope it isnt to big engine.
I'm not real familiar with that 21 version, (I do have a GPM Racing TVP for that, and it's nice). I assume that version ran a 21 engine, and I think it will fit. I've yet to find a vehicle (all flat chassis, however) that won't fit a 28 and a 25 or 21. If it required a new engine mount, I would be worried though.

On the other hand....HPI is real shady about parts fitting. They cut corners, so who knows. It's only TVP design I've owned so can't compare it with others...but I have other HPI vehicles so I know them pretty well. That Savage has some design flaws, IMO. But that's why we love it. It's one of the most fun vehicles to upgrade, IMO.

As for overpowering it? I wouldn't worry. You can tune the weight transfer/suspension to help keep the front down if it gets bad. They can be overpowered tho. I imagine the modded ones could be perhaps. Remember, the engine is big, which means it's heavy. I've seen 21's overpower truggies (and that is hard to do). A major factor in how fast and explosive a nitro vehicle is its power to weight/ratio. I don;t know science too well, that I know first hand. There are ways to keep it durable and light...and as fast as you want it to be. (y)
 
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OnThatPipe

On a vacation
Messages
63
By the way, what pipe are you running with that? What pipes do the manufacturer recommend? If you are using a stock pipe, I'd definitely look to get something different for it. You noted you are new to the hobby so I can tell you when you change out a component pipe (like the one on the Savage) with an actual tuned inline, pipe...it will make it seem like any engine sound like a new engine. It's not a must, but as you begin to learn to tune it, you'll really want to drive something to augment it as it will help tremendously, IMO.

I can't speak to which pipes have been working with that LRP but if all else fails you can get any of the OFNA/Dynamite series (063, 053, or 086) for either torque, mid-range, or high-speed. I assume it would need a HS pipe but you never know. (I think it's a 5 port, and they sometimes like torque pipes. Make the sure the header exhaust plate doesn't interfere with your starter housing regardless of pipe. I have multiple make of each EFRA series pipe listed above (OFNA, O.S Dynamite, Nova) and the header exhaust plates are different between each of them. If Nova didn't have a reversible starter housing,, it would be difficult to run some of their pipes, let alone other brands, so let's hope the LRP has one so you have more choices. (y)
 
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Nitroholic

Member
Messages
38
Location
Sweden
Thanks for the input. I Will be using the New pipe i bought with it, witch is seen in one of my prevouis pics. I can get you a more decent pic later but i just got a New phone and don't know how to take screendump yet.
 

OnThatPipe

On a vacation
Messages
63
Thanks for the input. I Will be using the New pipe i bought with it, witch is seen in one of my prevouis pics. I can get you a more decent pic later but i just got a New phone and don't know how to take screendump yet.
Groovy. Definitely try to post up vids when your get it going and I'm sure we can get you thumping with that engine. Just remember when you break it in, don't be afraid to begin leaning it out after the first tank. The worst thing to do is leave it rich too long because the internals will get gummed up and it will effect peak performance. A lean engine will sound worse than rich one, so you'll know if you get it too lean for too long. Back in the day guys would break their engines in during qualifiers...lol.
 

olds97_lss

Well-Known Member
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2,180
Location
Dekalb, IL 60115
My LRP28S3's and LRP30S2 both like the losi HT pipe off the LST. I tried a few pipes with them and found out of what I had, the HT pipe worked best. The others I tried were the HPI Polished, HPI ribbed, HPI stock, RD Logics weird side pipe, OFNA generic pipe off an old buggy I had and an XTM 21 pipe. I run a LRP28S3 in my big block revo as well and use the THS big block rear revo pipe on that. It does well too. The LRP's seem to like a more restrictive pipe than what the HPI's are. Running the HPI pipes caused a very muddy/burbley mid-range that I couldn't tune out. The HT pipe allows me to tune for clean running throughout the entire range.

I modified the flange a bit on the pipe so I could use the high flow HPI header with it with a typical coupler, but I also made a little L bar under the middle of the pipe to support it. That also has the side effect of making the header gaskets last forever.
 

Grumpy1822

Savage Owner
Messages
790
Location
Kenner, Louisiana
I have a stock .32 and one from neal. Both run great on the ofna 086 or nova 9886 pipe. That engine is a torque monster so a low end pipe 053 or jp1 will make it a wheelie monster that will peak and fall quickly. The top end pipes will shift the power curve towards the middle to upper rpm range.
 

InTheZone

Active Member
Messages
76
Yes the LRP will direct bolt to your truck, you will be using the flywheel and clutch but you may think about going to alloy shoes and a bit heavier springs like a 1.1 set

If you gonna upgrade the :ercm: to that LRP then you will want to also upgrade the differentials to the 29/9 machined gearsets and also upgrade the spider gears to the 4 spyder and also upgrade the differential cups to stronger alloy parts...

Putting more power in is going to reveal the weaker parts really quickly for sure.....
I'm in a similar scenario. I have an SS that I haven't used in over 10 years, probably closer to 15 years, engine is bad (screwed up head and block casing trying to remove stuck head) and I want to get it in running condition. Since coming back I've seen a lot of things go down with certain companies, including HPI. I cannot for the life of me find these "machined" bulletproof 29/9 gearsets. I've found a bunch of "sintered" gearsets from previous model Savages, but even still I feel like those won't hold up as they look to be generic chinese knockoffs. And trying to find people parting out either of the newest model Savages to get the latest and greatest diff is impossible as well.

AMainHobby has HPI parts on their site, but most are listed as "back order" and I'm not even sure they'll be able to get those in stock, unless HPI now works as a "per request" partner.

Thanks for any help.
 

olds97_lss

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2,180
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Dekalb, IL 60115
For what it's worth, the sintered BP ring gear holds up well to nitro. Can't recall if I have sintered or machined in my flux hp, but I do have them in my X. I've busted a few of the BP pinions, those are all machined.

rc4me.us has some good looking BP pinion/ring gears. I haven't bought those yet, but for the price, they are worth a try. I don't believe they are OEM, but the parts I have bought from them have been holding up well. I have their super 5sc transmission with a center diff in it in my flux hp and all the steel gears are holding up really well.
 

InTheZone

Active Member
Messages
76
For what it's worth, the sintered BP ring gear holds up well to nitro. Can't recall if I have sintered or machined in my flux hp, but I do have them in my X. I've busted a few of the BP pinions, those are all machined.

rc4me.us has some good looking BP pinion/ring gears. I haven't bought those yet, but for the price, they are worth a try. I don't believe they are OEM, but the parts I have bought from them have been holding up well. I have their super 5sc transmission with a center diff in it in my flux hp and all the steel gears are holding up really well.
Thanks, I'll look into those. From what I know so far all Flux models have the BP machined ring gear
 

olds97_lss

Well-Known Member
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2,180
Location
Dekalb, IL 60115
Thanks, I'll look into those. From what I know so far all Flux models have the BP machined ring gear
Yeah, I got mine used and can't recall what's in it. I did lose one of the big fat HPI 4mm course threaded screws in the rear diff once... instead of damaging the gears, it literally split the case in half. That was a very short bash session... sounded horrible.

They look machined:


I've broken 3 pinions in that truck before I got the super5SC transmission. Haven't run it a ton since I installed that, but I did run quite a few times.
 

Nitroholic

Member
Messages
38
Location
Sweden
Hi! haven't changed the engine yet, mainly because i use the truck frecvently, meanwhile i have been collecting the things i need too support this raw power the lrp hopefully Will provide. But when me and my friends where out ripping dirtroads the truck went from running Nice til not running so Nice at all. I ended up with that the truck from time to time lost power and began slowing down and then to accelerate again. Lost idle. Lost power on rearwheel, its now frontwheeldriven. Gonna try and post pictures. The lack of idle was due to a broken clutch shoe. Good thing I bought everything to mount when the lrp gets in. The lack of power was due to the fact that i was able to shatter the spurgear. But i need your help to point me in the right direction when it comes to why it wont drive on the rearwheel? When i lift it and hold it in the air, push the throttle, all wheels spinn Nice. But when its in the ground, its Only frontwheeldriven. Any suggestions? Taking the opportunity and mounting the 3 speed tranny i bought. I got it assembled, but had to take it apart anyway, because i had to transfer the reverse module to it.

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olds97_lss

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2,180
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Dekalb, IL 60115
Check the center cups. The screws like to fall out and or shear off and sometimes there's enough friction on the output shaft of the trans or input shaft of the rear diff to allow it to spin without the screw/pin holding it in place. One of those things where if they milled the shaft and cups to mate to each other with the screw/pin just holding it, may have made a stronger assembly that was less likely to rattle the screw out.
 

Nitroholic

Member
Messages
38
Location
Sweden
Check the center cups. The screws like to fall out and or shear off and sometimes there's enough friction on the output shaft of the trans or input shaft of the rear diff to allow it to spin without the screw/pin holding it in place. One of those things where if they milled the shaft and cups to mate to each other with the screw/pin just holding it, may have made a stronger assembly that was less likely to rattle the screw out.
Thanks for the response. I'm not sure i know which one you mean.
 

Jam Racing 1

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HPISF Supporter
Messages
4,790
Thanks for the response. I'm not sure i know which one you mean.

He means the drive cups on the transmission, they are held on by screwpins also the cups on the differentials are held on in the same way.... do you have a manual for the truck, it should be covered in there also
 

olds97_lss

Well-Known Member
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2,180
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Dekalb, IL 60115
If the brakes work, it's likely not the brake hex/cup that the disks float on, it's the one on the diff:


I don't have a photo handy of the cup on the other end of that dog bone, but there is one and it's also held on with a screw/pin.
 

Nitroholic

Member
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38
Location
Sweden
If the brakes work, it's likely not the brake hex/cup that the disks float on, it's the one on the diff:


I don't have a photo handy of the cup on the other end of that dog bone, but there is one and it's also held on with a screw/pin.
Yes, now i understand. I know that the outer ones are ok, gonna check the inner ones to.
 

olds97_lss

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2,180
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Dekalb, IL 60115
It could also be a sheared pin for a wheel hex. You kind of need to hold the rear tires while looking at the drive train and see where the spinning stops. Harder to do with gas, but if you put it up on a table, raise the front tires off the ground, then give it a bit of gas while looking underneath, you should be able to see where the drive train stops spinning to diagnose where the issue is.
 

Nitroholic

Member
Messages
38
Location
Sweden
It could also be a sheared pin for a wheel hex. You kind of need to hold the rear tires while looking at the drive train and see where the spinning stops. Harder to do with gas, but if you put it up on a table, raise the front tires off the ground, then give it a bit of gas while looking underneath, you should be able to see where the drive train stops spinning to diagnose where the issue is.
Perfect! Going to fint out tonight. I Believe its the rear diff because from what i han remember, the brakes work. Going to try to lock the cup in place, with a welding plyier. Since the diff seem to work, i would need 3 hands checking this, but by locking it momentarly would probably work just fine. Posting photo of the rims to my rear wheels. Any thoughts? If it cant hold for the nitrostar BB 21, it will probably not last long for the LRP.
 

olds97_lss

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2,180
Location
Dekalb, IL 60115
Yeah, if that's slipping, that would cause it too. I find that the HPI hex's aren't that great. They fit ok, but they have soft corners and tend to wallow out HPI wheels. Every time I try running stock HPI wheels, that happens at least on one after a short while.
 

Nitroholic

Member
Messages
38
Location
Sweden
I bought the engineScreenshot_20190817-103317_Drive.jpg without backplate. I was under the impression that an sh backplate Will fit but the cc measurement on the holes are incorrect? I Will attach an image that i got along the roto start and backplate. Does anyone know what the measurement are in the LRP since this is no match?
 

Jam Racing 1

Well-Known Member
HPISF Supporter
Messages
4,790
What brand of starter is that ??? have you removed the backplate yet and seen if it will even line up the mounting holes??
 

Nitroholic

Member
Messages
38
Location
Sweden
What brand of starter is that ??? have you removed the backplate yet and seen if it will even line up the mounting holes??
Its sort of a noname. Modelcraft. Bought it to my original .21 engine. As the pictures show, the don't line up and since lrp backplate is no where to find, i need to know if Another backplate the lrp Will fit? In Another thread at this forum i found that the sh backplate did fit. Since this supposed to fit sh engine too i took a chanse it should fit but no way near. Otherwise i will Wait and see if i can get an LRP pull start or rotostart.
 
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