baxternick

My Feedback: (19)

I have a OS TZ .18 mounted in my vegas and had a few questions. First what is the average temp you guys are getting on the head. I am between 150, and 165 and was scared to go anymore lean until I got some advice. I just don''t know much about car motor''s or boat motors, because I do giant scale planes. Also what prop have you guys found to be the best for this boat and combo. I have a Y535 on the boat right now and it seems fine, but the boat tops out at 41.5 on the gps. I have done the JD sponsoon mods, but other that than a turn fin the boat is stock. I also have the cooper pipe in the boat.

baxternick

My Feedback: (19)

Here''s a few pics of the two boats with the exact same setups running yesterday.

Jerry Dunlap

Are you wrapping any cooling coils around the head? Head temps in the range you stated are good. I''m running a X437/3 blade. Two other guys in our club are running M440s on their MV/TZ 18 boats.

JD

Spetz

You know you can buy the OS18CV-RM head from towerhobbies for about $25 and that fits the TZ
Temp wise I am not sure though, but definately they will run less than 200 if water cooled. Probably considerably less than 200 as they run much cooler than car heads

baxternick

My Feedback: (19)

Yes I have the coils just like the pics in the thread showed on your tz. The motor still has more in it I think, but I do not want to run it lean. Thats why I wanted to see what a average temp was. Thanks for the reply.

speed8

My Feedback: (7)

Hey man
Our vegas was hauling it this weekend . Mine is rapped like yours and running 144 to 154 degs . dose anyone know if there is a mod class running in eastern NC . Would like to see other guy run their vegas. Thanks Bax''s see you at the pond.

Sean Bowf

The CVRM head is NOT a direct bolt on swap onto the TZ...you have to do some milling of the button and of the screws/screw holes to get it to fit.

Though temperature can be manipulated with fuel mixture...these are kind of two different things. You do need to figure out what fuel mixture works best, and you need to figure out which temp works best...but you want to kind of do these two things seperately.

My personal opinion is that the TZ likes to run hot. I have heard the buggy guys run them pretty hot (I have heard everything from 220 to 280). The problem is, that water boils at 212...so water cooling is probably not to possible at those temps.

Another problem is heat inside the cowl. The way we mount our engines, the carb is on the back side of the engine...so any heat that comes off your engine goes past your carb...and is sucked into the carb.

Some of the best runs I have had with my TZ were only a couple laps. I think the reason for this is the heat build up inside the cowl finally gets to the point where the engine is not running right due to so much heat being ingested into the carb.

So...temp kind of has to be a trade off between the engine running well for 6 laps, and what you can squeeze out of it for top speed.

I am running a MAC 3.5 pipe, and I think my HSN was 3 turns last time I ran the TZ(which is when I also broke the rod).

Sean

Dan S

I must concur on this one, I run my buggy between 220 and 250 but
my boat engines all run between 135 to 160.

Like Sean said don''t use the temp only for tuning, this is to be used only has a tool to help you.

Dan.

baxternick

My Feedback: (19)

Will other than the props mentioned by Jerry what are you guys using?

Sean Bowf

Jerry has a lot more knowledge on this than I...or most folks for that matter...do.

M440 was a good prop for speed. X437/3 is a good heat prop (slower than the M440 for me). I started with a Y535 and Y536 with the TZ...both wind up pretty fast so they are probably not enough prop for the engine. I also tried other 2 blade and 3 blade props...but came back to the 2 main props mentioned by Jerry. From octura, I think those are the main props to use unless you have the capability to mod props...then there might be other options to try.

Without a sponson mod...my TZ would turn a lot of props, but never really seemed to be hitting the pipe real hard. The sponson mod is what freed it up to try a few different props on it.

Sean