Increasing top speed of 712M

Jon_Gilbart · Post by **Jon_Gilbart** » Thu Apr 02, 2009 8:55 am

It has been suggested that the best way to increase the top speed of a 712M is to swap in the transfer case of the 710 and to get larger diameter tires. My Pinz can currently run 55 mph (88 kmh), and perhaps a LITTLE bit higher, but that's about it. Can I expect to see 65 mph on the highway w/ these changes? I'm trying to decide if it is worth the expense to do this... If I do swap the t-case in, is this a direct bolt in swap, or will I have to do a lot of modifications? Also, where can I find a 710 t-case for a fair price and what is a fair price to pay for it? Thanks. -Jon

EvanH · Post by **EvanH** » Thu Apr 02, 2009 10:01 am

Not to be insensitive, but if highway speed is important to you, wouldn't you be better served by a different sort of vehicle?

Any changes you make to improve top speed will be at the expense of low speed performance.

I lived in Maryland for a while (Edgewater). It was hard to find a place to hike, let alone drive off-road.

-Evan

David Dunn · Post by **David Dunn** » Thu Apr 02, 2009 10:12 am

Jon
If "all is right" with your 712M, and sporting 255/85 tires (33"), you should be at about 67mph at 4500rpm, and with the 710 transfer case ( or a 710

), 74mph.
But, if you do long trips at highway speeds, figure to be easy on your engine and drivetrain and run at 80%....Think in terms of your body, if you run "all out", you get tired quicker than if you jog at a slower pace.
The faster you drive, the more heat and friction is generated, and things wear faster, and the chance for premature failure greater.

Dave

Jon_Gilbart · Post by **Jon_Gilbart** » Thu Apr 02, 2009 11:22 am

EvanH wrote:Not to be insensitive, but if highway speed is important to you, wouldn't you be better served by a different sort of vehicle?

Any changes you make to improve top speed will be at the expense of low speed performance.

I lived in Maryland for a while (Edgewater). It was hard to find a place to hike, let alone drive off-road.

-Evan

If there was a vehicle that did everything well, I wouldn't have 5 vehicles. The Pinz is unique--that is why I have it. It's fun to drive around town, and that's cool with me. If I had a huge trailer and a big truck, I'd tow it to Rausch Creek and Green Ridge State Forest and other places, but I don't. So for now, I have to drive it wherever I'm going to off-road it. As you know since you lived around here at one time, people drive about 70-80 mph on average on the interstate. Going 55 mph MAX is pretty harrowing, to say the least, w/ people running up on your vehicle at speed. If I have to sacrifice some low end performance, I really don't care about that b/c I like my Pinz too much to beat the snot out of it off-road anyways. -Jon

dokatd · Post by **dokatd** » Thu Apr 02, 2009 11:29 am

I have 34" swampers on my 712M. It can hit 70 on flat ground. Now, as far as I know it still has the 712 t-case. Are you limited to 55 because of power or from bad feelings at high RPM

Jon_Gilbart · Post by **Jon_Gilbart** » Thu Apr 02, 2009 12:04 pm

dokatd wrote:I have 34" swampers on my 712M. It can hit 70 on flat ground. Now, as far as I know it still has the 712 t-case. Are you limited to 55 because of power or from bad feelings at high RPM

First problem is I have the stock Moloya tires... This I plan to remedy soon. It could probably go a LITTLE faster than 55 mph, but since the tag near the 3 locker levers says 88 kmh (55 mph), I didn't want to push it too far past that. The RPM's sound to be pretty high at that speed, too, but I don't have a tachometer to confirm that. The Pinz feels stable at that speed--WAY more stable than my Jeep w/ 35" wheels--it's just that I don't want my engine/driveline to explode from revving it too high. Even the Priuses are passing me at 55 mph!!!

Jon_Gilbart · Post by **Jon_Gilbart** » Thu Apr 02, 2009 12:14 pm

David Dunn wrote:Jon
If "all is right" with your 712M, and sporting 255/85 tires (33"), you should be at about 67mph at 4500rpm, and with the 710 transfer case ( or a 710 ), 74mph.
But, if you do long trips at highway speeds, figure to be easy on your engine and drivetrain and run at 80%....Think in terms of your body, if you run "all out", you get tired quicker than if you jog at a slower pace.
The faster you drive, the more heat and friction is generated, and things wear faster, and the chance for premature failure greater.

Dave

Thanks for the info. Acutally, all is NOT right, and perhaps that is part of the problem. It takes my Pinz a LONG while to warm up, and it stumbles quite a bit when cold. I seem to always be adjusting the choke, and it seems to like it better w/ the choke pulled out some, even after I run it for a while. If I don't let it warm up for about 10 minutes, then it's darn right dangerous to pull into traffic for fear of it coughing (kind of like a mild backfire) and sputtering. After it warms up, it gets a lot better. I was fine driving over 1000 miles recently, ONCE it warmed up. I have yet to do ANY maintenance on it, b/c I just got it a couple of months ago, but have been wondering if I should go w/ one of the fuel injection options, or try upgrading the plugs/wires/ignition system and tuning the carb or re-jetting it. I've never really done much w/ carbs b/c most of my cars have had fuel injection, so I'm leaning towards pitching the carbs and biting the bullet on the fuel injection system. -Jon

dokatd · Post by **dokatd** » Thu Apr 02, 2009 12:44 pm

Actually your top speed stock should be 93KPH or 58MPH. Your low range top speed should be 48Kph. That is straight from the op manual.

Jon_Gilbart · Post by **Jon_Gilbart** » Thu Apr 02, 2009 12:52 pm

dokatd wrote:Actually your top speed stock should be 93KPH or 58MPH. Your low range top speed should be 48Kph. That is straight from the op manual.

Hmmm... Perhaps you're right. I figured that little plate near the locker levers listed the top speeds for each gear in kmh. I don't speak or read German (?) however, so really don't know for sure what it says! I'll take a picture of it and hopefully someone can translate it. I've had it around 93 kph before, and the "Imminent Destruction" idiot light in the dash didn't light up, so either the bulb is broken, or I'm still good.

dokatd · Post by **dokatd** » Thu Apr 02, 2009 1:00 pm

Your right, even mine says 88KPH on the placard. And your translation is correct. But I think or assume it was ammended at some time. Or maybe it was a Military issued placard rather than a civilian one. The 93KPH was pulled from both an op manual and a repair manual

David Dunn · Post by **David Dunn** » Thu Apr 02, 2009 1:41 pm

The placards are only good if you have the original POS Maloyas ( Swiss spec models, or Austrian with Semperits).
The speeds I gave above were with electronics speedos programed for the specific tires.

No one drives a Pinz with Maloyas on the road in the US... At least no one without a death wish

Jon_Gilbart · Post by **Jon_Gilbart** » Thu Apr 02, 2009 2:23 pm

David Dunn wrote:The placards are only good if you have the original POS Maloyas ( Swiss spec models, or Austrian with Semperits).
The speeds I gave above were with electronics speedos programed for the specific tires.

No one drives a Pinz with Maloyas on the road in the US... At least no one without a death wish

Apparently, that is part of the problem. I have the POS stock Maloyas, and drove all the way from Arkansas to Maryland with them. Let's just say I drive VERY carefully... I hope to have new tires VERY soon.

David Dunn · Post by **David Dunn** » Thu Apr 02, 2009 3:01 pm

Jon
In the defense of the Maloyas, they are a democratic tire on a 712... whenever driving on a wet road, and there is a bend in the road... the tires will have a vote, usually 4 to 2 in favor of going straight

I learned that on a freeway overpass at 55mph... needless to say, there was a dictorial overthrow the following day, where the Maloyas were replaced with BFGs that see things my way.

diesaroo · Post by **diesaroo** » Fri Apr 03, 2009 12:27 pm

Sounds like you're going to do a tire change. Another option other than changing the t-case is mounting a strobe.

My dad has a sprinter van that he drives at 55mph for fuel economy reasons on the interstate. He got a cheap 12v amber strobe light that sticks to the back door with a magnet and plugs it in when he gets on the road.

People see it far off and move over early so nobody rides his bumper.

Ugo · Post by **Ugo** » Sat Apr 04, 2009 2:59 am

I have a 712M that I use for rock crawling. I would put some tricks into it to make it capable to do 120 mph on highway in full safety.
Any hints?

Ugo
Torino, Italy