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Old 06-18-2017, 11:06 PM   #1
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Default LRP ZR.28 Spec 4

So, 10 years or so after the release of the undeniably awesome LRP ZR.28 Spec 3, LRP now has a Spec 4. Anybody have one?

I see in the description they have tried to improve the idle characteristics with a new carb, and it's listed as a 6+1.

Unfortunately the old nitro MT days are mostly gone. Still, anybody got one? I'm in a holding phase out of nitro cars for a while, but am always still interested.. Same top end as the Spec 3, really better idle, will all the old backplates fit, run time, etc?..

Nitro Motor ZR.28 Spec.4 Pullstart | Product | LRP Home


I think racing is so mega-lame. Too much time required, too much money, too many over-serious Stiffly Stiffersons involved (i.e. fun-killers), etc. Such a shame that MT bashing died off. There are hardly any good trucks on the market now to put this thing in....

And yeah, electric has some advantages in terms of sound and ease of use. But just like with real cars, they will never have the soul of a real fuel-burning high-revving honest to god mechanical engine...

Long live nitro.
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Old 06-19-2017, 05:54 AM   #2
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Come to Florida, and we shall bash.

I might get one of those spec 4s. It will probably end up being a blah blah with a different head on it (like typical) but who knows!
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Old 06-19-2017, 06:19 AM   #3
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Ha - I'd like that...

The Spec 3 is listed as an 8+1:

Nitro Motor Z.28R Pullstart Spec.3 | Produkt | LRP

This changed, because I think they used to be listed as a 8+2 or something, but the engine gurus said the second exhaust port didn't count or whatever. But iirc, the Spec 2 was a 6+1 port. As was the Dynamite Big Red .28(which I had, and which was good also.. - though I think not quite the top end of the Spec 3/454)

Whatever the case, in my experience the ZR.30X is the best MT engine I ever had, mostly because of the carb. It idled like a race engine. Smooth, low, and constant. My LRP Spec 3, 454, Big Red, and all my Mach 427's and Sportwerks 26's were great performers, but would load up and cut out if you left them idling. They were still all great engines for the money, and super easy to break in and tune, but the idle was often a bit sketchy. Not so the LRP ZR.30X. Maybe the new Spec 4 is the same... I wonder if it has the Spec 3's top end.. Which, when tuned right, is awesome in an MT. 10 (!!) years ago, people were saying the Spec 3 was as if made for the LST2.. And it did run (and sound) great at full tilt in an LST2...

I don't even know what current trucks would be worth putting a new engine like the Spec 4 in. I would imagine LST nitro parts (engine mount, tank mounts, clutches, etc..) are getting hard to find. I'd love a brand new LST2 to put one in.. I probably have enough spares to get a new chassis up and running. My two trucks are just thrashed though. Probably 15 gallons between both of them.. - and multiple engines, clutches, diffs, trannies, etc..
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Old 06-19-2017, 06:32 AM   #4
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The Big Red is my current SH based mill, and it's far softer on the bottom than any of my other big blocks. That MAY be due to the Ofna buggy header I'm using coupled with the fact it's in an XL with taller gearing but I don't care enough to investigate honestly!
As for what truck...
My buddy got an Arrma Talion. It would be trivial to convert that thing to nitro. I googled it, and I dont see where anyone has converted ANY Arrma stuff. (Probably because electric is so fast ha)

My rigs are worn out too. Every diff cup, every suspension pivot point, ect. Loosey goosey.

Last edited by timjs; 06-19-2017 at 07:39 PM.
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Old 06-19-2017, 07:27 PM   #5
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Worn out? I call that bind proof.. XD
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Old 06-19-2017, 10:12 PM   #6
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The Talion is just a truggy. I have an RC8T.

For me a basher MT needs a 2-speed..
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Old 06-20-2017, 05:30 AM   #7
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Quote:
Originally Posted by wolf16731 View Post
Worn out? I call that bind proof.. XD
Yeah? You should see the death wobble my XL gets at high speeds! Haha

Quote:
Originally Posted by Herrsavage View Post
The Talion is just a truggy. I have an RC8T.

For me a basher MT needs a 2-speed..
Can't disagree there.
The only single speed truck I own is my Bullet, and it's got a fourstroke on it (more reason I should convert it to 2 speed I suppose).

Anywho, I am really considering picking up this new LRP. It's hard to justify though because all of my trucks have good engines on them at the moment and I even have a couple NIB engines already sitting around that I got for some reason or another.
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Old 06-20-2017, 05:46 AM   #8
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Trust me, I know how it is..

I'd give it a miss then.. Wish I would have given lots of RC (car) things a miss over the years...
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Old 06-20-2017, 03:47 PM   #9
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I just bought one from Germany and I'm expecting to arrive in a few days, hopefully in time to break it in this weekend, it's all in the hands of DHL I will install it in a LST XXL, with its original pipe and header. I will let you know how the whole process went through
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Old 07-05-2017, 07:15 AM   #10
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I just bought one from Germany and I'm expecting to arrive in a few days, hopefully in time to break it in this weekend, it's all in the hands of DHL I will install it in a LST XXL, with its original pipe and header. I will let you know how the whole process went through
Any updates on this? Im curious if the spec 4 is any better than the spec 3. Is it really less ports or are they just advertising it like this because the extra ports are just bypass ports? If it is less ports id imagine it doesn't rev as high as the spec 3 .
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Old 07-06-2017, 12:56 AM   #11
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Not yet. But this weekend it will be done. I will open the engine anyway and will take some pictures, if you want
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Old 07-06-2017, 01:11 AM   #12
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The Big Red was supposedly a modded Spec 2, but for all I know they were identical. In terms of performance it was very good. If anything, maybe a bit less top than the Spec 3, which on paper anyway makes sense, since the Spec 3 had more ports... Overall I'd take a 3 over a 2..

I'm not really an engine guru or anything. I just know what I like. It would interest me though to know if there is a difference between the Spec2/Big Red and the new Spec 4, and if so, what are those differences? Is it really an all new engine? Neither the Spec 2 nor 3 were +1's afaik...
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Old 07-06-2017, 04:15 PM   #13
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What I can do is to compare the spec 4 with Losi 454, which is a spec 3, if I'm right.
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Old 07-07-2017, 04:50 PM   #14
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What I can do is to compare the spec 4 with Losi 454, which is a spec 3, if I'm right.
That would be great, from what I understand the 454 is basically a spec 3. Looks like lrp is dropping a 32x spec 4 which I'm guessing is replacing the 30x. I'm kinda sad that they discontinued the 30x.
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Old 07-07-2017, 11:45 PM   #15
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The 30X is the best MT engine I ever had for sure..

The Spec 3 was awesome for the money - and had great top end. And like all LRP's was easy as heck to break in and tune. The carb though could have been a bit better. Like on the 30X.

That said, I was amazed the last few times I ran the 454 in my LST2. It idled perfectly and ran great.. It really ripped to a degree I wasn't quite expecting. Go figger'.. And this was after long periods of not being run...
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-LST2 #1 with Losi 454 & LST2 #2 with Dynamite Big Red .28
-Ofna DM-1 with silver Mach 427/2047
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