catbutt

46u: It's not so much the heat of the air, but the heat from the ground. It rarely gets 100 here, but its as humid as possible being oceanside. The sand retains alot of the sun's heat and transfers it to the car. I run 20-30 degrees cooler on pavement or grass. I don't run more than 250 even on the sand, but I would prefer to run 220-230. I am looking for as many ways as possible to keep my engine as cool as I can.

Gruder: Is there a noticeable difference in the weight between the plastic diff cups and the alloy ones? Suppose I should as the same of the cooling head. I'm not looking to add more weight, a small gain I could live with. Being that it is larger in diameter with more fins, I would expect it would cool more efficiently and weight slightly more as well. They also claim 7075 alloy displaces heat better than 6065, so that should be a factor also. I'm no metallurgist but it seems logical. I suspect the 7075 weighs a bit more, too. Keep us posted on your progress.

rclynx

Backwards Catbutt 7075 is more dense and doesn't cool as well as the lighter metals and usually small blocks disapate heat much faster than a big block and don't need a larger cooling surface (bigger Head) to keep tempratures down, thats why FMR is so important in the ST's. 220 to 260 is a good range to be in with the small block 280 and up is hot but some racers will live dangerous and run at 280 to 290 range because some of them scream at those temps.[:-]

MiamizFinest

dam long time i dont check in here.....i think next time i chime in this thread will be in the 1,000's page LOL

hey CATBUTT why not try a vented flywheel before gonig to a diffrent cooling head.......it can drop temps by atleast 20-30 degrees...........

46u

My Feedback: (3)

250 is no where near too hot. Just keep in mind that running to cool under 220 or so can be as departmental to the health of the engine as too hot. Yes I like to stay under 280 but if I have good smoke I will run up to 300 on my big blocks sometimes. I never tune to any certain temperature but tune for performance and smoke then check temperature. If it is 220 to 280 I do not worry.

catbutt

I tune by performance as well, I just use the temp to monitor how everything is working. If I am running outside of my usual temp range I know that there is something up, such as a bearing having gone out and the like. Any additional stress in the drivetrain will raise my operating temps, an early warning of a problem. I use sound , rmp, and smoke to get my engine tuned right. I simply want to extend the life of this engine as long as I can. I do understand the hazards of running to cool as well, I don't think that will be a problem where I drive at

boohoo

has anyone tried using a k@n air filter on there car i was thinking of replacing the filter on my mt2 and savage just want to see if there any good or rubbish

46u

My Feedback: (3)

K&N air filters are great for on road 1 to 1 vehicles but I sure as heck would not put one on my RC vehicles. They do not filter near as good as the stock one as long as you keep the stock one clean and oiled. If you do a search on this site you will see most feel the same way.

murawskiallen

just get an HPI high flow filter

boohoo

thanks for the advice i already have a high flow on mt2 just looking for something to make it breath easier but all stick with it thanx for advice i like to now wat the experts think first thats why i was asking thanks again

46u

My Feedback: (3)

The K&N filters they sell as RC filters are nothing but 1 to 1 crankcase filters. In reality they are nothing but a rip off. [X(]

Gruder

My Feedback: (3)

Cat,

I did allot of number crunching the total surface aria of the stock head is 35,538.22 mm2 and the NOVA head is 46,437.00 mm2. The NOVA head is about 31% bigger, you’d think that more surface aria equals more cooling. Not the case here, the K factor of the 6061 (stock) Al is 104, and the K factor on the 7075 (NOVA) is 70. The stock head is anodized witch reduces its efficiency at cooling the engine. My best calculations say that the heads cool about the same, one is no better than the other. So unless you’re going to get it for the look or the strength factor like I did, I would say stay with what you have. If my testing shows different results I will post them.

Stock head weighs 71.56g with 11 cooling fins
Nova head weighs 82.81g with 15 cooling fins

Diff cup
Stock plastic = 3.50g
Nova Al = 8.90g

I hope this helps, like I said I will post actual results once I get the truck on the road and get it tuned.


Bryan

46u

My Feedback: (3)

I would think all engine manufactures take cooling in consideration and the stock head should be more the adequate. Like I said I have never had a problem with stock heads and keeping engines in a acceptable range even in 100 plus degree weather. To be honest at my age the engines do better in hot weather then I do! LOL Yes the Nova looks really cool and I run their clutch shoes in my Savage and buggy. They make quality products but do not see the need for their heads other then looks.

catbutt

Thanks for the info, Gruder. I'm not in it for the bling, so unless actual testing shows different results than your calculations, I'll stick with the stock head. There is a fair amount of weight difference in the alloy vs. stock diff cups also, even though we are talking grams. I wonder if the extra strength they provide is needed. I'll have to get more than 2 months on my car to be sure, see how my diffs hold up. Although I haven't had my car long, I have alot of hours on it, 10-12 a week. I go out nearly every day for an hour or more, 3-4 on weekends. The only problem thus far is to be expected with sand, bearings wear quickly. It is tons of fun though. Keep us posted on your progress, Gruder.

rcuser75

hey guys, great thread. I just recently bought a MT2 RTR (i know, big mistake [:'(]) slow from a dig. had to replace the spider gears and final diff gears in the rear, fronts are going to need new final diff gears soon.

sooooo....

I was wondering. are the diffs in the new G3.0 RTR stronger? if so, will they work on the old MT2? and what about the G3.0 motor? is it there alot more TQ from a stop? I wanna spin wheels and not have to worrry about breaking stuff.

Other than that, I love my MT2

TIA

MastaDizasta

I'm gonna be doing a o.s.18tz conversion soon..
Here are the parts so far-
O.S. .18tz-tx
Header
gpm diff housing
New yeah racing front arms and a pair of jaco foams since I broke the old ones.
I'm still waiting on the aluminum diff cups for the spider gears...

stadium truck freak

hey guys how are you all just though id say hello . hows the mt2s going and what up grades you got scince i last logged in ?

rcuser75

hey MastaDizasta, I was considering the O.S. .18 CV-R. whats the difference?

Thanks.

catbutt

Don't know much about the g3.0, but you need the hardened gear set for your diffs, HPI part # 86336. Make sure you shim the play out of all the gears in the diff assembly, otherwise you will be buying new gears constantly. I believe the shims are HPI part # Z892, but doublecheck that first with the 18ss manual on HPI's site. You can also get the shims from here: HPI part # A431, but it comes with a case, which you don't need, but MAY at some point. It also comes with a few smaller shims for the spider gear shafts, but you only get a few of the 2 types of shims. There is a possibility you made need more than are supplied with the kit. I got the set with just the shims, but it was 2 months ago, the bag and part number are long gone, along with my memory. I think the first part number I gave you is correct and what I got, although. I have the RTR version myself, it was the smart move for me, as it was my first car. I have spent enough on upgrades to buy another mt2, but it was the way to go for a newb. From now on, now that I have experience to draw upon, it will be nothing but kits for me. Also, go to HPI's site on download the manual for the 18ss to your computer. You will need it in the future for upgrading your entire drive train. You will want to do this, sooner than later. As it is cost prohibitive, you might do it a piece at a time, which is how I did it. I just ordered the last pieces of that puzzle for me, the CVDs and hardened diff drive cups. 46u and a few others were giving me the business about it, as I said I had full 18ss drive assembly, but was misssing those two items [>:] So as of early next week, I will be able to say I have the 18ss drive-train and mean it! About the only things I need to get for my car now are the alloy shocks (my originals always leak) and a HD servo for the steering. It's good to see light at the end of the tunnel. Good luck to you, rcuser75, keep us posted on your progress.

Don't CONSIDER getting the OS 18 CV-RX, get it! It's the best engine suited for the mt2. Once you have one, you will never look back.

46u

My Feedback: (3)

Am I missing something catbutt? [46u and a few others were giving me the business about it, as I said I had full 18ss drive assembly, but was missing those two items So as of early next week, I will be able to say I have the 18ss]

If I am not mistake all the RTR even the new 3.0 have the crappy final gears. [X(]

catbutt

Maybe, 46u, it was just a joke about you pointing out the parts i was missing, no offense intended. That is all. The incident still haunts my nightmares...I wake up in a cold sweat, crying bitter tears of remorse for having mistakingly said I had an 18ss drive-train, which I did not. The shame I feel has left me scared and unable to make love to my wife. Ok, ok, now I'm really getting out of hand here, sorry. You did, however, convince me to get the CVDs and HD diff drivecups, they should be here early next week. I figured getting them was the only way to get rid of the nightmares and shame. J/K

evo165

Me too am waiting for mine OS TZ from Tower Hobbies. Their online price are not consistent, I got mine for $119USD and now the price is $199USD which is exactly the same engine which i ordered. [:-] Lucky me...

rcuser75

Thanks for clearing that up for me 46u because I was gonna get the G3.0 RTR diffs thinking they were stronger than my current ones.

catbutt, thanks for your help. once my motor blows (I'm sure it'll be soon as I like to run it lean and mean) I will be getting an OS .18 CV-R? whats the X for and whats a TZ. there's a hobbytown near me and they have a OS .18 CV-R for $99. Is this the one I should get?

Thanks.

Oh and btw, has anyone here played with the 3.0 motor from HPI? just wondering if its any good.

rclynx

There are some differences in the OS .18 cvr and the final letters behind the cvr are what tells you its exact application......I think you have an SG crankshaft.........just make darn sure you have the right OS .18 there not all the same[&o]

stadium truck freak

im gonna try and fit a mach 28 in my mt2 i know the diffs will go but will be good run while it runs lol il post pics of it when i get round to fitting it

MastaDizasta

The o.s .18 cv-r is a really good engine, thats what I have been using.
The only difference is that the o.s.18 tz is a lot more powerful..