Sunrader engine choices

[eljefe]

On a Sunrader what engine would you recommend with an auto trans especially on a 21 footer. I noticed TurboGregg has the turbo. I've also followed his posting on the difference between the turbo and v-6. Does this mean I should steer away from the 4 cylinder? If I understand TurboGregg right v-6 first, turbo 2nd. TurboGregg, any thoughts on the intriguing Lexus V-8 and auto tranny swap? Thanks for your help.

[Gulfstream Greg]

I always suggest for folks to find a V6 in the larger rigs as they have more horsepower and a better transmission. The turbo 22r's (22rte) are really rare, almost non existent in the motorhomes. So that basically leaves you with four choices, the V6, 22re (fuel injected), 22r carbureted and the 20r (carbureted early years). Many are very happy with the smaller motors and just take their time when climbing mountains. Even the V6 and my turbo are not going to blast you up a mountain and even a lot of hills will force you down drastically in speed. If you are ever considering towing a trailer a shorter rig with a V6 is the best option. TurboBob is doing the Lexas conversions but I have not seen or read about the final product and I do not know if this was V6 to Lexus or 22RE to Lexus. If it all works smoothly it sounds like a really good option except maybe the extra HP into the transmission.

In California I had considered buying a Sunrader 18 footer and converting it to a larger motor so I called the State Smog Board. Everything from the donor vehicle such as computer, transmission (the transmission talks to the computer), any smog equipment and dash lights would also have to be incorporated into the swap. I did not give up on the idea it was that I was able to buy our rig with a Toyota factory turbo. I mention factory turbo because in California adding a turbo to a non turbo engine will have a lot of details to work out with being smog legal. Personally if I was to upgrade to a turbo on a non turbo engine I would find a same year turbo truck and swap out everything then replace the turbo with a t3-t4 hybrid. I will eventually replace the stock turbo with a t3-t4 hybrid as mine is nearing its life line. I should back up a step and give some history of the oem turbo. They have some issues with heat. They tend to burn a hole thru the housing near the waste gate. They are slow to spin up. The factory exhaust is considered to have been designed to small. Its a $$$$ replacement to upgrade not to mention the modifications but I know of several who have done it and it is worth the effort.

Anyhow back to engine swaps. Besides the Lexus I know there have been other engines used. I do not know the model number but many have swapped in an in-line toyota 6 cylinder.

Here is a note regarding the turbo compared to the V6 and 22re. At high altitude the V6 and 22re will produce superior horsepower when the throttle is cracked open, such as from a stop. The reason for that is the turbo engine is far lower in compression than a standard engine and will produce substantially less horsepower at high altitudes (even low altitudes) until the turbo spins up and starts producing some boost. Another reason for the t3-t4 upgrade. Every engine is degraded in horsepower at a higher altitude but the turbo even more so because of the lower compression. Where the turbo does show its talents is on the open road and climbing steep grades. I have an advantage that my rig is a 4x4 with a set of lower gears. I can actually start off in the lower gears and shift the transfer case back into regular range while moving.

Here is another note worth contemplating. The factory turbo pickup trucks use the V6 transmissions and V6 drive trains such as rear ends. The rear ends are a Moog point in the motorhome as you should have the full floating axle. The beefier transmission is a consideration because what it gives you is a locking torque converter. The locking converter produces far less heat than the 22re non locking ones. The big issue of using overdrive is even more of an issue if you boost your horsepower and feel you can now use OD with a non locking converter. A transmission swap might be a bonus if you swap out an engine to a larger HP. As an example I have found that if my transmission is running hot and I am in a situation where I can switch into OD such as on the freeway I can actually watch the temp drop, I mean you can visually watch the needle drop.

Hope all that made sense, basically that's why I always suggest to find a V6. Its not just a bigger motor, its also a bigger transmission with a locking converter. Also as a side note turbos need premium gas only, no regular ever.

[eljefe]

I always suggest for folks to find a V6 in the larger rigs as they have more horsepower and a better transmission. The turbo 22r's (22rte) are really rare, almost non existent in the motorhomes. So that basically leaves you with four choices, the V6, 22re (fuel injected), 22r carbureted and the 20r (carbureted early years). Many are very happy with the smaller motors and just take their time when climbing mountains. Even the V6 and my turbo are not going to blast you up a mountain and even a lot of hills will force you down drastically in speed. If you are ever considering towing a trailer a shorter rig with a V6 is the best option. TurboBob is doing the Lexas conversions but I have not seen or read about the final product and I do not know if this was V6 to Lexus or 22RE to Lexus. If it all works smoothly it sounds like a really good option except maybe the extra HP into the transmission.

In California I had considered buying a Sunrader 18 footer and converting it to a larger motor so I called the State Smog Board. Everything from the donor vehicle such as computer, transmission (the transmission talks to the computer), any smog equipment and dash lights would also have to be incorporated into the swap. I did not give up on the idea it was that I was able to buy our rig with a Toyota factory turbo. I mention factory turbo because in California adding a turbo to a non turbo engine will have a lot of details to work out with being smog legal. Personally if I was to upgrade to a turbo on a non turbo engine I would find a same year turbo truck and swap out everything then replace the turbo with a t3-t4 hybrid. I will eventually replace the stock turbo with a t3-t4 hybrid as mine is nearing its life line. I should back up a step and give some history of the oem turbo. They have some issues with heat. They tend to burn a hole thru the housing near the waste gate. They are slow to spin up. The factory exhaust is considered to have been designed to small. Its a $$$$ replacement to upgrade not to mention the modifications but I know of several who have done it and it is worth the effort.

Anyhow back to engine swaps. Besides the Lexus I know there have been other engines used. I do not know the model number but many have swapped in an in-line toyota 6 cylinder.

Here is a note regarding the turbo compared to the V6 and 22re. At high altitude the V6 and 22re will produce superior horsepower when the throttle is cracked open, such as from a stop. The reason for that is the turbo engine is far lower in compression than a standard engine and will produce substantially less horsepower at high altitudes (even low altitudes) until the turbo spins up and starts producing some boost. Another reason for the t3-t4 upgrade. Every engine is degraded in horsepower at a higher altitude but the turbo even more so because of the lower compression. Where the turbo does show its talents is on the open road and climbing steep grades. I have an advantage that my rig is a 4x4 with a set of lower gears. I can actually start off in the lower gears and shift the transfer case back into regular range while moving.

Here is another note worth contemplating. The factory turbo pickup trucks use the V6 transmissions and V6 drive trains such as rear ends. The rear ends are a Moog point in the motorhome as you should have the full floating axle. The beefier transmission is a consideration because what it gives you is a locking torque converter. The locking converter produces far less heat than the 22re non locking ones. The big issue of using overdrive is even more of an issue if you boost your horsepower and feel you can now use OD with a non locking converter. A transmission swap might be a bonus if you swap out an engine to a larger HP. As an example I have found that if my transmission is running hot and I am in a situation where I can switch into OD such as on the freeway I can actually watch the temp drop, I mean you can visually watch the needle drop.

Hope all that made sense, basically that's why I always suggest to find a V6. Its not just a bigger motor, its also a bigger transmission with a locking converter. Also as a side note turbos need premium gas only, no regular ever.

[Gulfstream Greg]

eljefe

Your reply contained only the quote, no message.

[eljefe]

Thanks Turbo Greg for all your help on the choice of engines and trannys for Sunraders. I sincerely appreciate all the time and effort that you took to help me out and reply to my posting. The information helps me immensely in doing the right thing for myself. Again, heart-felt thanks and kudos to you Turbo Gregg.

[Gulfstream Greg]

Your welcome

Sunraders are supposed to be a bit more aerodynamic so maybe they slice thru the wind better and if thats so they might need less horse power than some of the other rigs. Bottom line though coach manufacturer really does not matter, they are all Toyotas and they all have to get up a hill. The bigger the coach and the amount of cargo including passengers is a factor when deciding if you need V6 or 22re. If you live and mostly travel on flat terrain a 22re might just do fine. Just remember no matter even if its a V6 its not going to climb a hill like a V8.

[futar]

One engine swap I haven't heard feedback on is the GM 4.3 liter V6. I saw one Toy MH conversion for sale earlier this year. It is a true truck V6 with good torque (245 ft/lbs) and reliability. The Astro vans use it. One consideration in engine swaps is the front torsion bar. The GM V6 is light enough to not worry about. Comments??

[Gulfstream Greg]

One engine swap I haven't heard feedback on is the GM 4.3 liter V6. I saw one Toy MH conversion for sale earlier this year. It is a true truck V6 with good torque (245 ft/lbs) and reliability. The Astro vans use it. One consideration in engine swaps is the front torsion bar. The GM V6 is light enough to not worry about. Comments??

A 4.3 lit would be sweet. You should see if you can dig up any info about such a swap and post it. My guess is you would want to also use the gm transmission so that the engine trans and computer all talk to each other.