Jump to content

Recommended Posts

My question is this - at what is the best speed to drive my '90 Toyota Dolphin V6 Automatic camper?

Here's my dilemma: The V6 engine is buttery smooth, so I can't tell by ear what it's doing (or there's too much creaking, popping, whooshing noises coming from the house that I can't hear it) .  But this is what I can gather happens:  Start 1st gear - around 15 MPH, switch to 2nd gear - around 30 MPH, switch to 3rd gear - around 55-60MPH, overdrive.  So far so good.  But then, I get to a mild overpass and there is an uphill the size of an ant's back, and the speed drops PRECIPITOUSLY if I don't do anything with my right foot.  Then, I think it goes back to 3rd gear.  As soon as it goes to 3rd gear (or if I switch off the overdrive), then speed picks back up and actually goes UP, to like 65 MPH without me doing anything with my right foot.  If I press, I know it will do 75 MPH.  But I don't want to kill the engine or transmission (I don't think it has a transmission cooler).

So, it seems like 55-65 is the sweet spot, and it's also where the transmission struggles deciding whether overdrive or 3rd gear is best.

And I want to drive around 65, especially in Arizona where the interstate speed limit is 75 but everyone is driving 90-95 like they're going to collect an inheritance or their hair is on fire (or both).

So the question is: Given that I want to drive 65, should I:

a. Switch off the overdrive, stay in 3rd gear and drive up the RPM's and give my engine an early death?

b. Leave the overdrive on, tone down the RPM's, and kill my transmission?

c. Is there a better option?  Please tell me, and thanks!

d.  Would I benefit from having a tachometer so I can decide what's best (I'm smarter than the Toyota computers, assuming) and if so, what type?  And no, I don't want to swap a dash from a 4Runner or a fancier Toyota Truck, so don't even suggest that.

Link to comment
Share on other sites

So you know virtually all vehicles downshift when going up hills, right. Not  big deal. OK to step on the gas to keep your speedup but if it's shifting in and out a lot turning off overdrive on the hills is fine. Neither is going to hurt your engine or transmission. Fine to use overdrive on flat roads and downhill too. Of course you can drive 65 to 70. The main thing that is going damage is your wallet. Gas mileage is best at 55 to 60. I will never understand this man thing about going as fast as the other cars on the road. I putt putt along in my 4 cylinder and have never had a horn honk or hit in the back or a single negative response from other rivers about my speed. Only quite a few thumbs up cause my camper is so cool. 

Linda S

Link to comment
Share on other sites

There are a lot of variables going on, 55 is the sweet spot if you want to save some fuel. Dead flat ground maybe OD. Your trans has a lockup converter what this means it becomes a direct coupling to the engine kind of like  stick shift so when the going gets tough the lockup disconnects there is a bit of science involved but the bottom line is now the converter is involved it does some interesting things but it "slips" this heats the trans fluid not a real good thing. 55 is kind of the cut off point where it can't makeup it mind. So 65 is doable and it will shift out of lockup on an incline. You are basically driving a brick it has all the aerodynamics of a brick so the coefficient of drag increases with speed sometimes making it difficult for the trans to stay  in lockup. Saving fuel at speed is not an issue in any RV experience because it won't happen.

Link to comment
Share on other sites

Wow.  I have a 94 Warrior and always wished it had a lockup trans but thought it was too old for that.  But if a 90 Dolphin has a lockup then I suppose my 94 does too.  Sweet.  I agree on driving 55 to max fuel economy.  If I am in speed limit 75 then I may cheat all the way up to 57.

Link to comment
Share on other sites

A 4Runner cluster will run $200, a Small tach will run $30. Heres an example... https://www.ebay.com/itm/Bosch-FST-7906-Sport-II-Tachometer-2-5-8-New-in-Package/264294550990?hash=item3d892ecdce:g:NggAAOSwx5hbw7j2.

To make your engine really happy you need to change the rear axle ratio. Common upgrades are to 4.56 or4.88. $450-$650 eBay

Link to comment
Share on other sites

47 minutes ago, WME said:

To make your engine really happy you need to change the rear axle ratio. Common upgrades are to 4.56 or4.88. $450-$650 eBay

So what is the stock ratio?

Link to comment
Share on other sites

Your comments and questions make it pretty clear that you understand the limitations and issues involved here.  There is no great solution, and you listed the basic options for dealing with it.  Personally, I choose option "A":

18 hours ago, lopezg273 said:

a. Switch off the overdrive, stay in 3rd gear and drive up the RPM's and give my engine an early death?

High RPM's are not a problem.  These engines have no problem running in the 3000's (although I'm speaking of the 4 cylinder, not the 6 but I assume that 6 is also just fine up to 4000 with no problem).  I run about 3600 and 62 MPH as normal in 3rd gear.  I rarely turn the OD on.  Yea, it's loud, but I've got power, MPG is fine and I don't worry about overheating the tranny fluid due to torque converter slippage in OD.  Running 65 in 3rd is not unreasonable, you just have to get used to the sound and feel.  Then you use OD in the rare circumstances where it can keep speed.

18 hours ago, lopezg273 said:

c. Is there a better option?

Given that you have a lock-up OD gear you may benefit from a gear change in the rear. (mine is a 4 banger so I don't have lockup in OD). If you put a 4.88 or 4.56 in the rear then you are going to be able to use OD at higher RPMs on the highway and this may help the OD work better and let you get up those minor hills without so much trouble. The downside to me is that with the 4.88 the top speed in 3rd gear is limited.    I've been watching for a used 4.88 to show up locally for a decent price so I can try this gear instead of my 4.1 diff, but haven't found one yet. There are various gear calculators out there that will help you figure out what the RPM would be in which gear.   I think you can read the VIN tag and decoding it will tell you what the stock diff gear is in your rig (odds are it's 4.1).  You can always go back to your 4.1 if you don't like the results with the different diff.

I found the addition of an aftermarket tach to be time and money well spent.  It's really useful to be to be able to monitor the RPMs even with an automatic.

Changing to a manual transmission is another option, but that's too much work IMHO.

Link to comment
Share on other sites

Yes the engines will turn some pretty good revs. I drive a 2011 Tacoma and pull a camper it has a 6 speed manual and a 3.56 diff with a combined weight of about 7,200# as long as the RPM were above 2200 it had no issue no matter what gear it was in. I drove my old Nova Star 22RE as I would a stick shift when it began to struggle I turned off the OD quite often shifted to 2nd range manually to keep it from up shifting on long hills.   After awhile you begin to listen to what the engine is trying to tell you about where its happiest. I don't see any real need of making an engine turn faster than necessary to get the job done. 

Link to comment
Share on other sites

On 5/25/2019 at 7:18 PM, Maineah said:

There are a lot of variables going on, 55 is the sweet spot if you want to save some fuel. Dead flat ground maybe OD. Your trans has a lockup converter what this means it becomes a direct coupling to the engine kind of like  stick shift so when the going gets tough the lockup disconnects there is a bit of science involved but the bottom line is now the converter is involved it does some interesting things but it "slips" this heats the trans fluid not a real good thing. 55 is kind of the cut off point where it can't makeup it mind. So 65 is doable and it will shift out of lockup on an incline. You are basically driving a brick it has all the aerodynamics of a brick so the coefficient of drag increases with speed sometimes making it difficult for the trans to stay  in lockup. Saving fuel at speed is not an issue in any RV experience because it won't happen.

Thanks, I did not know it has a lockup converter so that alleviates my doubts about running it in OD mode at that speed.  I think I'll do both, get a small tach and maybe put it on the a-pillar so it does not crowd the cockpit and also try to remain in OD.  

 

On a related/not related note I have a head unit on it with Apple Carplay which gives me a bunch of cool tech including Sat/Nav, Siri, BT Streaming, rearview camera, and all that jazz.  I was looking/hoping for a Carplay-compatible app that would show engine management stuff (such as my RPM's), but mine not being OBD II, no dice.  With this Airplay unit (which I bought on eBay for $175), fits perfectly in the Double-DIN dash and my '90 has more tech on it than my 2017 Yaris iA.

Link to comment
Share on other sites

There are many devices out there but unfortunately they all need an OBD2 input. The small diagnostic port under the hood does have a tach output so that makes it a bit easier to connect a tach. 

Link to comment
Share on other sites

10 hours ago, lopezg273 said:

Thanks, I did not know it has a lockup converter so that alleviates my doubts about running it in OD mode at that speed.  I think I'll do both, get a small tach and maybe put it on the a-pillar so it does not crowd the cockpit and also try to remain in OD.  

 

On a related/not related note I have a head unit on it with Apple Carplay which gives me a bunch of cool tech including Sat/Nav, Siri, BT Streaming, rearview camera, and all that jazz.  I was looking/hoping for a Carplay-compatible app that would show engine management stuff (such as my RPM's), but mine not being OBD II, no dice.  With this Airplay unit (which I bought on eBay for $175), fits perfectly in the Double-DIN dash and my '90 has more tech on it than my 2017 Yaris iA.

Which radio unit did you go with? I’ve seen a lot of them and the car play looks nice but it seems like a lot of those units have sub part software and the interface isn’t very smooth.

Link to comment
Share on other sites

24 minutes ago, Odyssey 4x4 said:

Which radio unit did you go with? I’ve seen a lot of them and the car play looks nice but it seems like a lot of those units have sub part software and the interface isn’t very smooth.

I purchased the Power Acoustik CP-650 on eBay so if you search by that you can find it.  It's around $168 now.  I'm sure it's also available on Amazon.  Here are a few things I learned, that might help you:

1. There are WIRELESS and WIRED Apple Carplay connections.  The cheap units are WIRED which means when you step inside your vehicle the BT functions will work, but NOT Carplay.  When you plug your iPhone via USB to the unit, THEN Carplay works and also charges your phone at the same time.  If you want WIRELESS connection, at the time I purchased my unit (July, 2018) the only wireless Carplay units were from good brands (Alpine, Kenwood) but they were like $800, significantly more expensive.

2. Initially I could NOT get Carplay to work, I was very frustrated, and I was ready to send the unit back.  I contacted Power Acoustik and they answered (they are in Southern California) BUT they just told me "well, you have a newer phone and some people experience issues connecting" (I have an iPhone X) and their advice was to return it.  But because I don't know what I'm doing, and I also don't give up (I'm what you would call a "motivated idiot" - the most dangerous kind), I searched for a solution on the interwebs and just found that there is an obscure setting in iPhones in a section called "Screen Time" that you have to check, and I did, and the thing has worked flawlessly ever since.  I've found that most people who have issues with tech are idiots like me, but they don't find solutions, they just write bad reviews (unjustly).

3. I recommend a professional install unless you're very good with electronics and have lots of time.  Just adding a rearview camera to my Dolphin was worth the upgrade, but most cameras don't have long-enough cords (because they're meant for normal vehicles) and you have to work up a solution for the long cord and the mount.  But once you get a rearview camera, you'll wonder how you never ran over someone without it!  Plus, if you wire and aim it right, you can see how long the queue is behind you on a 2-lane uphill, haha.

4. Carplay is amazing.  With the simple upgrade, you thrust your aging RV into the future.  You can get turn-by-turn nav, Siri, it reads texts, allows you to answer by just dictating, you have an enormous amount of music available, rearview camera, etc.. etc...  I'd even go a far as to say that if you have a Toyota RV and you DON'T have Carplay (or Android Auto), I'd go as far as to call you "crazy".  

5. Lastly, with the CP-650 being a cheap unit AND it having a glossy screen (a touch-screen) and not matte, you do get reflections at some angles and the colors aren't what you'd call "amazing", but I had the same problems with my 2015 BMW and my 2017 Yaris, so, it is what it is.

Oh, and just because a unit has Carplay, don't assume it has Android Auto, and vice-versa.  So if you want Android Auto, this will not work, search for a unit which does have Android Auto.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...