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AFR gauge for carb engine?

661buster1963

Full Member
Joined
Feb 18, 2009
Messages
309
I am moving at a snail pace post retirement on a 68 bronco. I built 1971 351w with lunati voodoo cam with a paper estimate of 410 hp and 375 tw. I was planning a np 435 trans but moved to a nv3550, 4.88 Detroit with 31 spline with 35” tires, 3.5” suspension and a 1” body lift. Nissan extra ps box, dana44, tro conversion with Tom’s Dana 44 pan hard riser.

I have autometer sport comp
2 5/8” gauges for engine temp, oil
Pressure, vacuum, and volts (one wire alternator conversion), now I have some
Buddies recommending i get a transmission temp gauge so I dont cook the tranny
And a AFR gauge to properly jet the carb. Are these two gauges nice to have Or 100% required?
 
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661buster1963

661buster1963

Full Member
Joined
Feb 18, 2009
Messages
309
Also too
Much money in this
To do a lot of hard core
4wd, mostly
Going to be a Chevy killer, mall getter, ice cream and pizza ride in and around Myrtle beach. Some
Fire roads and public land hunting, not a ton of hard core 4wd road like to ran near Kennedy meadows when I lived in Bakersfield. Also a little
Worried about the nv3550
Surviving, have a diaphragm luck clutch
 

DirtDonk

Contributor
Bronco Guru
Joined
Nov 3, 2003
Messages
51,613
I am moving at a snail pace post retirement on a 68 bronco.
Sounds way too familiar and hits way to close to home!
I built 1971 351w with lunati voodoo cam with a paper estimate of 410 hp and 375 tw. I was planning a np 435 trans but moved to a nv3550
Good choice. The old 4-speed, as good and robust as it is, would be a far less "fun" box for that engine and your intended use.
4.88 Detroit with 31 spline with 35” tires, 3.5” suspension and a 1” body lift. Nissan extra ps box, dana44, tro conversion with Tom’s Dana 44 pan hard riser.
All good too. Except maybe for the Detroit on a street driven rig with lots of power. Especially in a 9" rear.
Not going to be a canyon carver, but one thing I would do would be to make sure you have the best shocks that you can have designed for your rig. Maybe (very much so!) a pair of anti-sway bars added to the mix. Or is that already on the list?
I have autometer sport comp 2 5/8” gauges for engine temp, oil
Pressure, vacuum, and volts (one wire alternator conversion),
I've always liked the vacuum gauges. Can find more uses for them than most think.
now I have some Buddies recommending i get a transmission temp gauge so I dont cook the tranny
I'm not completely against a temp gauge in a manual trans. But it's not really a thing unless you have an automatic. In that case, it's a REAL THING!
It would be hard to determine just what temperatures indicate cooking a manual transmission. Maybe there are some specifications out there for the special fluid used in the NV3550 transmissions? Check with the Dodge Boys on that one.
And a AFR gauge to properly jet the carb.
That's a great add these days.
Are these two gauges nice to have Or 100% required?
No, neither one is a requirement. Especially the trans temp gauge.
But the AFR gauge? SUPER helpful in verifying tune. We got away without them for many years, but now that they're so affordable, it's almost a no-brainer.

Also too much money in this to do a lot of hard core 4wd
Yep, like most anymore. But it'll be a fun ride anywhere you go.
Going to be a Chevy killer, mall getter, ice cream and pizza ride in and around Myrtle beach.
Also a little worried about the nv3550 surviving, have a diaphragm luck clutch
With very good reason to be worried!
It's not a drag race trans, but I have customer experience that says that they still hold together very well to a real beat-down given to them. Especially by one particular customer!
He'll race anything that comes along, and loves ripping around. Your 4.88's will help take some of the abuse of the 35" tires and powerful engine off of the trans. But not all of it.
Best to keep it all in mind, but still enjoy it. More torque would be a bad thing in this case, but it's still a powerful build. Way more than the trans was designed for.
The good news is that the vehicle is lighter (believe it or not) than it was rated for.
The big tires can put the hurt on everything between the clutch and the rear axle shafts. But the 4.88's transfer some of the load that the trans would see, downstream to the axle shafts.
Can't tell you just how to drive to keep the trans happy. Just that, if not totally abusing it, and making sure that it has the VERY specific lubrication in it, you can still get some good use/life out of it.

Paul
 

ared77

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Bronco Guru
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Apr 21, 2013
Messages
3,178
All I know is I ownned a yellow Pro/Street '65 Mustang fastback a few years ago with a stroker engine based on a 351 Dart block. AFR heads, carbed, about 427 cubic inches, Tremec 5 speed and an AFR guage. That car was as close to perfect to drive as any carbed car I've ever driven...and I'm convinced it was in part because of the tune/AFR guage.
 

Broncobowsher

Total hack
Joined
Jun 4, 2002
Messages
37,058
None are needed. But an AFR is more useful. Having a bad AFR will still run and drive good. There are signs it may be off. But a gauge will tell. But it doesn't have to always be there. A temp install until you have it tuned.

As for a manual transmission temp gauge. Probably going to cause more confusion while cures nothing. How hot do you think it should be running? No, they run hotter than that. Normal. Do you do hours long drives at highway speeds? The number of transmissions that have coolers. Couple of the 6-speeds. Superduty in a 1-ton. Some GM muscle cars with the .50 OD ratio. I did one on a non-bronco daily driver. It moves so slow, so much thermal mass. About as useless as the diff temp gauge. The diff temp swings a lot faster.
 
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661buster1963

661buster1963

Full Member
Joined
Feb 18, 2009
Messages
309
Trans temp gauge was suggested since I have paired the nv3550 and 351w, punching up a few grades in what the trans was made for. Lacking a gauge I won’t be able to tell if I am torturing it. The following is what my mostly jeep buddy was saying

Under 210, normal
220-240, getting hot, back off cool it down
250 plus cooling synchros and bearings
 

BigB

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Sr. Member
Joined
Nov 19, 2011
Messages
497
Trans temp gauge was suggested since I have paired the nv3550 and 351w, punching up a few grades in what the trans was made for. Lacking a gauge I won’t be able to tell if I am torturing it. The following is what my mostly jeep buddy was saying

Under 210, normal
220-240, getting hot, back off cool it down
250 plus cooling synchros and bearings
Never heard of anyone using a trans temp gauge for a manual, so I would take everything else this jeep buddy has said with a grain of salt. I'm surprised he didn't suggest adding a cooler.

You will know you're torturing a manual trans when it starts to make noise, be harder to shift, get stuck in gears or explodes.
 

DirtDonk

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Nov 3, 2003
Messages
51,613
Yeah, probably plenty of grenaded manual transmissions out there, with otherwise perfectly fine fluid temps I'd bet!
But if that seems like a good idea (I hear you with the potent motor in front of a trans that was never meant for it) then go for it. Assuming you can find an easy way to mount a sensor in the right spot.
You might be the first to start compiling data for it. Unless you can find some online support for the temperatures to watch for. Just because I've never seen such a chart, doesn't mean they don't exist.

Let us know which way you go.

Paul
 

ntsqd

heratic car camper
Joined
Jan 30, 2005
Messages
5,953
Loc.
Upper SoKA
I'd make the AFR gauge a temporary thing. Mount it with a magnet, power it from the a power-point, and remove the O2 sensor when not in use. Can use a spark-plug or an M18 bolt with a copper washer to plug the sensor bung.

Temp gauge on a manual trans is done in some endurance racing. No experience with one. I'd plan on using a synthetic lube in the trans if the NV isn't VERY specific about what lube to use (like they are with the 4500). Look up the specs on the lube that you plan to use, or better call the mfg's tech line and find out what temps the lube wants and doesn't want. I've had good results from Torco and Redline synthetic gear lubes. Not a fan of Amsoil, but that's mostly due to how it is marketed than the product itself. If the call is that it has to be dino oil then SWEPCO is the only answer.

Looked up the 3550 and it looks an awful lot like an Aisin R series! As in a LOT like one, down to the dowel pins on the b/h end of the main case. If it is related then there is considerable history with the R's in Toyota 4x4's and the AX15 in TJ's etc. The R's were also used in the manual trans Supras.
 
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661buster1963

661buster1963

Full Member
Joined
Feb 18, 2009
Messages
309
I thought the manual transmission template was a bit of a stretch, it sounds like if i had one I may be the only one doing so, so I won’t.
 

Broncobowsher

Total hack
Joined
Jun 4, 2002
Messages
37,058
I don't flinch at 250 manual transmission temps on something being worked.

A lot of the cooling is conduction through the Bell housing into the block.
 

73azbronco

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Bronco Guru
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Nov 11, 2007
Messages
8,778
worst case, temp gauge, in my case, I had a mixture adjustable rochester so it was easy to drive, test smell, then dial it in after each test. But an afr would be cool.
 

gnpenning

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Bronco Slave
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Dec 26, 2011
Messages
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Loc.
I have more questions than answers.
While a different animal, all the class 8 trucks I drove had trans and rear end gauges. Yes both rears. Hauling 80,000# is a different class. I liked being able to monitor all temps. With that said I've never felt much need to do the same thing with light duty rigs even with heavy loads. A temp gun is cheap and easy.

Setting up with AFR gauge is the advisable if you don't have an exhaust analyzer, even then with out a dyno you are only going to be accurate at idle and maybe off idle. After you are setup not much use other than to occasionally check unless you run into drivability issues.
 
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