Jerod's Supercharged T[u]RD Build

[gamefreakgc]

I have been planning and thinking and thinking and planning about changing the final drive ratio. I have 4.10s in the 4Runner currently, like many of us do. However, 1st gear is just way too tall. I mean it's massively tall. An engine that makes max torque from the factory at 4800 RPM and 1st gear goes to 43 MPH? Shame. The problem is, I'm having a hard time deciding which gears would be best. 4.56s are not tall enough as I had those in a previously Toyota Pickup. 4.88s look nice but is it enough? Should I go for broke and have tire-shredding power and put in 5.29s? All this on stock 265/70/R16 tires?

I came across a video by Engineering Explained (Engineering Explained - YouTube), a very helpful guy on Youtube I've been watching for years. He tests with hard data what things make power and what do not. He also changed his final drive ratio on his S2000 but decided on a certain ratio based on what he was after. He wanted faster 0-60 times. Full video here (it's a little dry and boring for some):

<iframe width="550" height="330" src="https://www.youtube.com/embed/DHhY_z1bYA4" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>



Basically, changing his gearing from 4.10 to 4.44 make his S2000 faster by moving the power band forward and not having to lug through the lower RPMs. If he had gone with 4.71 though, he would have to shift one more time before 60 MPH and would actually be slower. Taking this approach, I made the following chart:

The chart shows various gears, from 4.10 to 5.29 as well as a stock 5-speed, and what the maximum MPH is of each gear. The red line I added is the speed governor. Mine kicked in around 108 MPH on the dyno, which means any reading past then is irrelevant since I can't get the 4Runner moving that fast.

If I were building the fastest 4Runner that can to go from 0 to 108 MPH, I would want to do that with the fewest amount of shifts. Just based on this data alone, it seems the 4.56 gears would be the best choice as they max out right at the speed governor. But let's be honest, who drives that fast? I sure don't. If I were building the fastest 0-60 times, from the chart it looks like that 5.29 gears would be the best choice as 2nd will get you to ~61 MPH before shifting and getting the engine in the power band as quickly as possible. On a 1/4 drag race, you would also most likely have to shift an extra time into 4th before the finish line, so there's a real tradeoff between off the line power and top speed per gear. I do plan to take my 4Runner on the drag strip once I've finished the build.

There's one thing this chart doesn't show and that is cruising RPM. For the 4.88s it's at 2660 RPM at 70 MPH. For 5.29s it's 2880 RPM at 70 MPH. That might be a bit loud and obnoxious for a long drive.

Do you have any thoughts on which gear would be best? Any experiences? Please share if you do.

 

[Speedy]

The real problem in these old 4Runners is the trans being a 3 speed with OD.

I've changed gears on two trucks but I was trying to get back power and efficiency lost from larger tires.

On a 1991 Toy PU 4 banger I did 4.88s and it drove great. Tires were 31x10.50.

 

[phattyduck]

If I were building the fastest 4Runner that can to go from 0 to 108 MPH, I would want to do that with the fewest amount of shifts. Just based on this data alone, it seems the 4.56 gears would be the best choice as they max out right at the speed governor.

Not so fast - the shift issue is only for manual transmissions (or slower single-clutch SMG-type tranmissions). With the auto, you are putting down power through the shift (slightly more, due to dragging the RPM down), so that isn't an issue.

If you were really pushing things drag racing, it might worth avoiding extra shifts in an automatic - but that would be due to wear and tear, not speed.

I'd still vote for whatever gear will leave you with an RPM you can stand on the freeway at your normal cruising speed.

-Charlie

 

[T4topher]

Do you have any thoughts on which gear would be best? Any experiences? Please share if you do.

Well if you go 5.29’s and you end up not being able to stand it you could always increase your tire size to 265/75/16 or 285/75/16.. vs re-gearing again would be pretty $$.. but I vote for the 4.56’s or 4.88’s if your 100% set on not increasing tire size..

 

[gamefreakgc]

I emailed Arron at Bad-Ass Racing Engines - custom street and race engines. (lots of great tech tips on his website that I have used in my build) and he gave some great info. He was able to guess my RPM's at cruise basically spot on with a 4-speed automatic:

Hi Jerod, sluggishness off the line is definitely gear ratio related. When selecting a set of gears, you have to determine where you want your best performance, be it off the line and 0-60 MPH acceleration, or top speed, or just a general all-around basic mediocre performance by splitting the difference between the two.

You mentioned "around town" driving so I am assuming you won't be doing too much freeway driving. Right now, using the math, you "should" be at about 2,160 RPM at 60 MPH with your current 4.10s in overdrive, so 4.88s will raise your RPM up about 400 RPM or so. It doesn't sound like much but it's the difference of riding a 10 speed bike and trying to do a wheelie in 1st gear as opposed to trying to do one in 3rd gear. It's a LOT harder to do a wheelie in 3rd gear, but it's super easy in 1st. Off the line acceleration is much quicker in 1st gear on a 10 speed bike than it is in 3rd gear. You should feel about that same kind of acceleration difference between your current 4.10s and 4.88s as that bike gearing scenario.

Just for shits and giggles, the 5.29 gears would definitely make your SUV a 0-60 MPH beast! At 60 MPH with those gears and your current tires, you would be taching about 2,788 (2,800) RPM at 60 MPH in overdrive. If off the line and "around town" performance is what you want and you don't drive long distances over 60 MPH, then those 5.29s would turn your SUV into a real jack rabbit! Laying rubber would get a LOT easier as well. You'd feel a HUGE difference from what you are running right now.

He builds really impressive big block Chevy engines as well as does gearing and suspension. Quality work and has had national recognition for his cars and engines. The 4.88 would be the happy medium where as 5.29 would make it a '0-60 beast'. I forgot to tell him my transmission has torque converter lockup so the RPM's won't be as high as he mentioned. I think his advice might be tipping me in favor of 5.29's.

Like you said T4topher, I could easily change out the tires to something larger if it's too much. But I doubt it would be, I want this thing to rip!

 

[gamefreakgc]

Spend yesterday driving around 2900 RPM on the highway. Found out my engine has an intake whistle at that RPM that sounds a lot like Gopher from Winnie the Pooh. I don't think I'd be able to put up with that on a long drive. Going 70-72 MPH. And I don't like the idea of driving like a grandma in the slow lane to keep the RPM's lower. 4.88's it is.

 

[gamefreakgc]

A recent photo of what my engine looks like as of today. Didn't realize how colorful it's become, oh well.

 

[gamefreakgc]

Torque Converter Unlock Switch

I've been thinking about the regear and adding a bit more flexibility to control my automatic transmission. We can down shift easy enough at speed, O/D off takes care of that. Staying in 2nd is a pain but can be done by shifting to "2" on the gear selector. There is situations though where 3rd is too high and O/D (referred to as 4th) is too low. As I regear, this will only become more pronounced as the RPM differences between the two increases. So I installed an interrupt switch to the SL Solenoid circuit here:

I have a URD patch harness so I cut the wire indicated and ran leads to a Scion switch in the dash:

I like blue since I installed blue LEDs in the dash years ago but there's other colors as well here: Scion OEM Style LED Lighted Rocker Switch | Remotes & Switches. This switch is a direct fit to our switch mounting holes and very clean looking as it's made by Toyota/Scion.

When I leave the switch on nothing is changed and when I hit 50 MPH with low throttle input in 4th, the torque converter locks up. If I hit the switch to 'off', the torque converter unlocks and will not lock up as the circuit is interrupted and keeps the RPM's just a bit higher. I have an external transmission cooler and high quality synthetic fluid so I am not too concerned about the heat the extra torque converter slip creates.

There is one issue, it does trip a pending code P0773. Two drive cycles with the pending will result in a CEL and disable the torque converter lockup as a fail-safe. The switch I have is a SPST, single-pole single-throw. If I had a SPDT or single-pole double-throw switch, I could have it send the signal to ground and solder in say a 20K resister and get away with no CEL. The ECU is only looking for a signal between 100K and 8K ohms so would not be hard to do. Anyone know of a lighted SPDT switch that fits that description? Or is there a way to re-wire so this isn't an issue? Here's a basic diagram of the switch:

Supply is the 12V signal from the ECU to activate the solenoid and Load is wire going to the solenoid. In the 'off' position the circuit interrupts entirely with no continuity but what if I swapped the Supply and Load wires? That way the Supply would be grounded instead of interrupted when it's 'off' and hopefully not trigger a CEL and when 'on' it still works as intended. Anyone know if that will work?

 

[Speedy]

I bet you could solve it with a relay if you can't find the appropriate swtich.

 

[gamefreakgc]

The switch for the transmission is working out ok. Since the CEL is on a two-trip circuit, as long as I don't use it for two consecutive drives the light doesn't come on. It's yet to turn on beyond a pending so far.

On another note, going to an from San Jose to go to Timmy's party I got 20.1 MPG! That's my best mileage ever on CA gas!

 

[gamefreakgc]

The electric fan is out for good. 3rd one broke in 2 years, I am guessing it moves too much and the vibrations are killing the bearings.

After I took it off, the 4Runner is noticeably slower off the line. I guess it saved more HP loss from the fan than I thought it did!

HP Increase:

-10 HP (probably more TQ than HP)

Running Total:

+164 HP

 

[brillo_76]

I wouldn't think it take alot of hp to spin the stock fan but it does take some when it's active. Bummer on your electric fans.

If you really want electric I try to find a Toyota radiator with the same dimensions as ours off a different model of Toyota and go that route.

Sent from my SM-A505U using Tapatalk

 

[19963.4lsr5]

One of the better electric fan setups back in the day was the dual fan from a Ford Taurus. The factory e fans last a long time.


Sent from my iPhone using Tapatalk

 

[Corey91mason]

Impressive

Man, I got to say, I'm one page 4 but I had to skip to the end already just to post. So much information! I have a 96, 5vz, 5 spd, 4x4 with rear mount and tuning has been a nightmare. I have to say I like the rear mount as a daily but the runner plan has changed and it's going under the hood soon, I currently have the urd 6 injector kit and it's rough going. Ping at high rpm/high boost if I'm not careful. So I'm going to dig real deep into your closed loop tuning and see what I can learn and see if the aem is going to be the better call or cut ties and go standalone. If money wasn't an issue I would have an aem by now but I found that urd for cheap unused. Hope to see you continue updating!

 

[gamefreakgc]

After seeing my gunked up transmission mount I decided it was time to switch it out. Not cheap though. Surprisingly, drive quality has improved. I would get a very harsh 'jolt' when shifting from P to D backing out my garage each day and that's completely smooth now. While idling at a stop light the vibrations I'd feel in the seat and steering wheel are reduced. Now I'm kicking myself for not changing the engine mounts when I had the engine removed a few years ago.

In other news, I ordered a set of 5.29 gears for my differentials. Yes, that's right folks, I'm going for broke and increasing the final drive ratio torque multiplier by 30%. This should be fun!

 

[4runnerfiend]

After seeing my gunked up transmission mount I decided it was time to switch it out. Not cheap though. Surprisingly, drive quality has improved. I would get a very harsh 'jolt' when shifting from P to D backing out my garage each day and that's completely smooth now. While idling at a stop light the vibrations I'd feel in the seat and steering wheel are reduced. Now I'm kicking myself for not changing the engine mounts when I had the engine removed a few years ago.

In other news, I ordered a set of 5.29 gears for my differentials. Yes, that's right folks, I'm going for broke and increasing the final drive ratio torque multiplier by 30%. This should be fun!

wow that is going to drive very different with 5.29's! will have to see the 1/4 miles numbers

 

[Speedy]

Wow 5.29s! I'm interested to hear how that goes. I've been thinking about some changes to mine as well and just can't decide whether to leave it a lone or not LOL. It's setup great but I was thinking some 33s (285s) and a 4.88 gears might be nice, but I think that opens a can of worms vs the 265s I'm running.

I did order some raptor style lights for the Satoshi grill though.

 

[busmup808]

I’m running 5.29s on 37s and I got my pep back. Going to be better when I install my blower. Just waiting on the injectors. Been subbed to your build even before getting my blower. Great job on your build.


Sent from my iPad using Tapatalk

 

[cl4Rk]

33s (285s) and a 4.88 gears might be nice, but I think that opens a can of worms vs the 265s I'm running.

Just out of curiosity what are your thoughts on running 265s with 4.88s?

EDIT: sorry [MENTION=115347]gamefreakgc[/MENTION] I did not mean to thread hijack. [MENTION=8729]Speedy[/MENTION] PM me if you want.

 

[gamefreakgc]

Just out of curiosity what are your thoughts on running 265s with 4.88s?

EDIT: sorry [MENTION=115347]gamefreakgc[/MENTION] I did not mean to thread hijack. [MENTION=8729]Speedy[/MENTION] PM me if you want.

It's fine, I don't own the internet. Post away.