4th Gen 4Runner v8 IFS Ultra4 Build - Opinions Needed

[Charles4x4]

I'm traditionally a land cruiser and 1st gen 4runner guy. But with all the advancements in IFS over the past few years, I'm excited to start a 4th gen 4Runner build for Ultra4. But first, I have to finalize a budget and need some opinions from the experts.


My plan: Start with a '06-09 4Runner v8 Sport. It'll be on 35's with 17" beadlocks to fit class rules. I'll remove most of the interior, glass, and cut the doors to half doors to save weight. I'll then add a cage to Ultra4 spec, add PRP Pro seats and 5-point harnesses, a ton of safety stuff to pass Ultra4 tech, etc. You get the idea.


For this build, I have to balance strength, reliability, compliance, and cost to keep it feasible. But I'm also pushing for sponsorship, so it has to look good. And it'll be the only one of it's kind in class, so it'll grab a lot of attention.


So here's where I need your help and opinions:

Front Suspension: Balancing Travel with Strength
- 4.5" Long Travel Suspension (19" Travel) from Solo Motorsports with all the goodies (Fabricated Spindles, Double Shear, etc)
- 10-12" King 2.5" Dual Rate Coilovers with RR and Adjustment Knobs on a front shock hoop

Rear Suspension: Balancing Travel with Strength
- HD 4-Link Arms in the rear. Looking at Metaltech, Total Chaos, or others?
- I can't do Coilovers in the rear due to the rules. So I'm looking for Long Travel Dual Rate Coils. Was looking at MetalTech Long Travel 3", but am not sure how much travel they offer. Ideally I need something that can match the front 19" travel if at all possible.
- 12-14" King 2.5" Smooth Body Shocks with RR and Adjustment Knobs


Drivetrain: Balancing Strength, Reliability, Budget
- Engine: I'm going to try to find a v8 model with 100-150K miles. What are the critical PM items I'll need to plan for? I've heard power mod options aren't great, so I plan to spend $ elsewhere.

- Transmission: I have to keep the stock transmission and it'll be an automatic. What, if anything, should I do to increase strength? I was also thinking of adding a trans cooler?

- Transfer Case: I'm thinking Atlas II, but it's $3K. How stout is the stock transfer case? Any chance it could last Ultra4 conditions?

- Front Diff: I know the 8" Clamshell 30-spline front diff is better than most stock toyota axles, but am worried about strength here. Aiming for 5.29s with ARB lockers. My alternative is a Currie F9, but it's $4,500 built and I don’t know if it’s small enough to fit in the factory location with a mount. Either way I'll be running RCV Ultimate IFS Shafts.

- Rear Diff: I could truss the stock rear diff, but again worry about strength here. Would match the front with 5.29s and ARB lockers. My alternatives are a Currie 9" to match the front or a Diamond 9". Currie is less $, but Diamond is legendary.

- Driveshafts: Custom from Tom Woods, JE Reel, High Angle, others?


Armor: Balancing Weight, Aesthetics, Strength, and Budget
- Front Bumper: Pelfreybilt (best approach angle), CBI, Addicted Offroad, or others?

- Rear Bumper: 4x4Labs (best departure angle), CBI, or others?

- Sliders: CBI (includes a Kick-Out) or others?

- Skid Plates: Bud Built, CBI, RCI, Shrockworks, or others?

- Winch: Definitely a Warn. Will a Zeon 10-S fit the front bumper options above?


Other: Balancing Weight, Functionality, Aesthetics, Strength, and Budget
- Steering: I can put a modified Tundra rack in, but am again worried about strength. My alternative here is a Howe Trophy Truck rack (2.5 or 3.0) or something else. The Howe rack is $3K and I'd need to add a pump to match.

- Fiberglass Fenders: Fiberwerx 4.5" Buldge

- Fuel Tank: I can run the stock fuel tank with a beefy skid (skid plate options above have a tank skid in their Full Skid System options). Or I can run an aluminum fuel cell in the cargo area. Lots of Ultra4 cars have fuel system problems, so I'd rather not touch the OEM setup if possible. But I am not sure how low the stock setup would hang below the fuel rail with the skid.

- Exhaust: I definitely need to get rid of the OEM rock-catching exhaust and plug in a lower profile muffler that would give a modest deep v8 sound. Opinions?

- Radiator: Will the stock radiator hold up fine? Or do I need a high performance option with a fan kit?

- Front Sway Bar: I'm not sure if I need a front sway bar or if the Long Travel kit will eliminate it. But I want to make sure it's stable cornering at speed. Was considering none, stock extended, or Currie AntiRock.

- Battery: Odyssey Extreme or Optima?

- Wheels: Will be 17" beadlocks - likely sponsor driven. Allied, Raceline, KMC, others

- Tires: Will be 35x12.50r17 - also likely sponsor driven. BFG KM2 or KM3, Nitto, Falken, Goodyear, others


I'm sure there will be other things I'll want to ask you all, but this is a nice list to start with. Note I plan on commencing the build in the next month and it'll be raced in the 2019 season 4600 Stock Class - so I'm hopeful I'm starting well in advance.

Thanks!

 

[Inv4drZm]

I would be looking at trucks with a minimum of 150k miles, anything less would cost a premium and you will be replacing everything anyway. These motors and transmissions will last forever just make sure they have a decent maintenance history.

For the rear suspension, I would relocate the factory 23 gallon fuel tank that hangs down super low, especially since you will only be running 35" tires. A tank skid will only decrease your clearance. Get a Ford fuel tank like some 3rd gen guys have done so that way you have tons of room for your driveshaft when you flex and you can fabricate a proper double triangulated 4-link rear suspension setup with heims on all ends of the links. You could move the axle back, extend the wheelbase a touch, and increase your departure angle if you trim you bumper and rear pinch weld. Probably my biggest limiter in the rocks right now is my fuel tank clearance even with my 35's (other than my unlocked diffs or stock geared t-case).

The MT LT kits for the rear are 11.5" travel shocks so I'd guess the springs are good for ~12.5" of travel at the shock (which is what, ~18" at the wheel?) Look at the shocks first, you will be limited by how high you can mount them in the wheel well and how low you want to mount them on the axle. You will probably come up with 12" shocks or maybe 14's if you can lower the axle side mount a hair or raise the frame side without the tires touching (custom width rear axle). You will want to strap that so subtract an inch from each. If the MT LT coils fall out then look into some custom ones from Coil Spring Specialties, they will build whatever you want for reasonable prices.

Trans cooler, power steering cooler, maybe an engine oil cooler and rear diff cooler if possible. Cool all the things in my opinion.

For front bumpers, Addicted Offroad would have the best approach angle right?

Isn't running a Tundra front diff still an option or what happened with that idea?

 

[4RunnerAquasport]

For the rear suspension, I would relocate the factory 23 gallon fuel tank that hangs down super low, especially since you will only be running 35" tires. A tank skid will only decrease your clearance. Get a Ford fuel tank like some 3rd gen guys have done

Already subscribed. Would love to do this.
+1 on Fuel Tank relocate. CaliFab CALIFAB ? Custom Metal Fabrication and Professional Welding Services makes some very beefy offset rear links and pan hard set that allow extra down travel. You can see with no shocks mounted, the spring makes contact before the link bottoms out on the tank, so relocating is a better solution. Good Luck!!!
P.S. Way Jealous......

 

[4RunnerAquasport]

Battery- Northstar is another choice. Own 3 of them.
Oh and jump on the exhaust bandwagon. I know I want one with some headers.
http://www.toyota-4runner.org/4th-g...high-flow-y-pipe-i-can-do-need-your-help.html
Maybe we can get them in production soon.....hello sponsor.....??
Would a true dual set up with a crossover work with the rules? Didn't someone on here put one together on a 4th?

 

[DZNUTS]

I would go with a set of Thorley headers. They’re a ***** to install, but they fix the exhaust leak you’ll have/are going to get & they give a noticeable gain in hp and tq.

Maganflow makes 1 piece Y-pipe (with cat) that will allow you to get rid of the two cats just past the collector of each header.


Sent from my iPhone using Tapatalk

 

[duffdog]

I would be seriously worried about the rear axle. The 8" rear gearset explodes just from looking at it, in a race I would give you 3 minutes till it blows up.

I would not consider anything smaller than a Tundra 10.5 rear axle for a race, the front clamshell I am not convinced is good for race duty, though I have not seen one blow up personally.

The transfer case might be good - you would be served to have it looked at by a shop that cuts planetary gears to see if you could possibly retain the case and get a lower 4:1 ratio cut. This would enable you to keep the Atrac system intact which might help you win in the rocks.

Most trucks overheat during the race. This is not normally a problem for any Toyota vehicle, but if you are worried about it, I have developed an auxilliary cooling system for the 4th gen trucks with in cab monitoring that allows for on the fly adjustment and computer controlled triggers for fan speed/ duty cycle.

With regards to the engine; since you are not driving this on the street, I would take the engine apart and get some strong rods and do forced induction. The 2UZ has some very advanced engine design tricks and all it needs are some strong rods and custom pistons and your choice of supercharger and you will have a very capable (and fast) 4runner.

The transmission may become an issue, but its nothing that a larger trans cooler and a trip to a transmission shop to go through the systems wouldn't take care of. A modified torque converter set up for racing would benefit you by making less heat and shifting firmer.

With regards to the bumpers, if you are racing I would get none of them. No CBI, no Demello, nothing. The goal in Ultra4 is to make your truck lighter by removing heavy things and adding tube. The bumpers will have to be made of tubing (also the undercarriage skids should be mostly tube based) You will want to remove any heavy stuff from the truck. The gas tank I believe by ultra4 rules MUST be a racing cell with either foam or baffles.

I am currently building a full exo 89 4runner for Ultra4, so most of this I have researched heavily. Your build seems really fun. What may differentiate your vehicle is that you have the ability to keep Atrac fully functioning even with crazy modifications. This may give you an edge that nobody else has.

 

[Charles4x4]

I would be looking at trucks with a minimum of 150k miles, anything less would cost a premium and you will be replacing everything anyway. These motors and transmissions will last forever just make sure they have a decent maintenance history.

Good to know. What PM is most important for a 150K mile vehicle? I'll likely order some OEM toyota parts and knock it all out at once.

For the rear suspension, I would relocate the factory 23 gallon fuel tank that hangs down super low, especially since you will only be running 35" tires. A tank skid will only decrease your clearance. Get a Ford fuel tank like some 3rd gen guys have done so that way you have tons of room for your driveshaft when you flex and you can fabricate a proper double triangulated 4-link rear suspension setup with heims on all ends of the links. You could move the axle back, extend the wheelbase a touch, and increase your departure angle if you trim you bumper and rear pinch weld. Probably my biggest limiter in the rocks right now is my fuel tank clearance even with my 35's (other than my unlocked diffs or stock geared t-case).

I read the entire 3rd gen thread. Looks like a ton of work - I think I'll stick with a 22 or 26 gal fuel cell in cargo area. Would also be worried about accessibility with the cell in the rear hidden under a huge skid to protect it in the event something goes wrong in a race. Cargo seems accessible, protected, and easier.

The MT LT kits for the rear are 11.5" travel shocks so I'd guess the springs are good for ~12.5" of travel at the shock (which is what, ~18" at the wheel?) Look at the shocks first, you will be limited by how high you can mount them in the wheel well and how low you want to mount them on the axle. You will probably come up with 12" shocks or maybe 14's if you can lower the axle side mount a hair or raise the frame side without the tires touching (custom width rear axle). You will want to strap that so subtract an inch from each. If the MT LT coils fall out then look into some custom ones from Coil Spring Specialties, they will build whatever you want for reasonable prices.

Good to know. With a fuel cell, I could do a custom 4-link in the rear (4WU maybe) and the MT LT coils may not have enough travel. But if the shock is the limiting factor, maybe HD version of the factory 4-link with MT LT coils is sufficient? Probably need to wait and do some measurements once I get the rig before I lock down the rear suspension.

Trans cooler, power steering cooler, maybe an engine oil cooler and rear diff cooler if possible. Cool all the things in my opinion.

Definitely a trans cooler.

For front bumpers, Addicted Offroad would have the best approach angle right?

Addicted Offroad and Pelfrey both have solid approach angles. I want a solid, but ultra light weight bumper if possible. I was considering Aluminum, but know they aren't as durable.

Isn't running a Tundra front diff still an option or what happened with that idea?

If the stock front clamshell won't work and I'm going to have to upgrade, I'm going to go big - a diff with a removable 3rd.

 

[Charles4x4]

Battery- Northstar is another choice. Own 3 of them.
Oh and jump on the exhaust bandwagon. I know I want one with some headers.
http://www.toyota-4runner.org/4th-g...high-flow-y-pipe-i-can-do-need-your-help.html
Maybe we can get them in production soon.....hello sponsor.....??
Would a true dual set up with a crossover work with the rules? Didn't someone on here put one together on a 4th?

Any exhaust goes for 4600 rules. But I need to spend my $ where I'll have the biggest impact...

 

[Charles4x4]

I would go with a set of Thorley headers. They’re a ***** to install, but they fix the exhaust leak you’ll have/are going to get & they give a noticeable gain in hp and tq.

Maganflow makes 1 piece Y-pipe (with cat) that will allow you to get rid of the two cats just past the collector of each header.


Sent from my iPhone using Tapatalk

How much gain in HP and Torque have Thorley Headers shown vs Cost? I heard the back two bolts are impossible to get to?

Any link to Thorley or Magnaflow? I can use search as well. If I just replace the muffler, what's the best option? I'm sure re-routing the exhaust is eventually going to happen, but that's an easy one.

 

[Charles4x4]

I would be seriously worried about the rear axle. The 8" rear gearset explodes just from looking at it, in a race I would give you 3 minutes till it blows up.

I would not consider anything smaller than a Tundra 10.5 rear axle for a race, the front clamshell I am not convinced is good for race duty, though I have not seen one blow up personally.

Agreed. I just finished speaking with Diamond and they are working on some "ideas" for me. Stay tuned.

The transfer case might be good - you would be served to have it looked at by a shop that cuts planetary gears to see if you could possibly retain the case and get a lower 4:1 ratio cut. This would enable you to keep the Atrac system intact which might help you win in the rocks.

Tell me more about the Atrac system? Note that I'll have ARBs F/R. And I'll need ultra low gearing in the transfer case (why I was leaning toward the Atlas II). But if I can keep the stock transfer case, that's a big win for the budget. I did Marlin Low Range gears in my FJ80 - they are great, but still couldn't get quite to 4:1 given the case size. For some reason I feel like I'll eventually have to bite the bullet on an Atlas II.

Most trucks overheat during the race. This is not normally a problem for any Toyota vehicle, but if you are worried about it, I have developed an auxilliary cooling system for the 4th gen trucks with in cab monitoring that allows for on the fly adjustment and computer controlled triggers for fan speed/ duty cycle.

Sounds intriguing. I was considering HD radiator, fan, trans cooler. But I'm not a cooling expert. More details?

With regards to the engine; since you are not driving this on the street, I would take the engine apart and get some strong rods and do forced induction. The 2UZ has some very advanced engine design tricks and all it needs are some strong rods and custom pistons and your choice of supercharger and you will have a very capable (and fast) 4runner.

I'll be driving it on the street some outside of Ultra4. And no forced induction allowed in 4600 (unless it was a factory installed option).

The transmission may become an issue, but its nothing that a larger trans cooler and a trip to a transmission shop to go through the systems wouldn't take care of. A modified torque converter set up for racing would benefit you by making less heat and shifting firmer.

Got it. Was considering a torque converter, but may be overkill for the v8.

With regards to the bumpers, if you are racing I would get none of them. No CBI, no Demello, nothing. The goal in Ultra4 is to make your truck lighter by removing heavy things and adding tube. The bumpers will have to be made of tubing (also the undercarriage skids should be mostly tube based) You will want to remove any heavy stuff from the truck. The gas tank I believe by ultra4 rules MUST be a racing cell with either foam or baffles.

I'm going to cut weight anywhere I can. But I also have to have protection and armor. And it needs to look good for sponsors. So it'll be a balance. No bumpers is not an option and I don't like the tube look on 4th gens.

Per Ultra4: "Safety fuel cells are required for all vehicles. Auxiliary fuel tanks may be added. Auxiliary fuel tanks must also be safety fuel cells."

I'll be running a fuel cell - it's easier and cheaper than the alternative.

I am currently building a full exo 89 4runner for Ultra4, so most of this I have researched heavily. Your build seems really fun. What may differentiate your vehicle is that you have the ability to keep Atrac fully functioning even with crazy modifications. This may give you an edge that nobody else has.

Nice! I've had two '87 SR5 Turbos as projects recently. You must be going for the Mod class. I need to know more about Atrac! Thanks for all the great feedback and keep it coming!

 

[duffdog]

Agreed. I just finished speaking with Diamond and they are working on some "ideas" for me. Stay tuned.



Tell me more about the Atrac system? Note that I'll have ARBs F/R. And I'll need ultra low gearing in the transfer case (why I was leaning toward the Atlas II). But if I can keep the stock transfer case, that's a big win for the budget. I did Marlin Low Range gears in my FJ80 - they are great, but still couldn't get quite to 4:1 given the case size. For some reason I feel like I'll eventually have to bite the bullet on an Atlas II.



Sounds intriguing. I was considering HD radiator, fan, trans cooler. But I'm not a cooling expert. More details?



I'll be driving it on the street some outside of Ultra4. And no forced induction allowed in 4600 (unless it was a factory installed option).



Got it. Was considering a torque converter, but may be overkill for the v8.



I'm going to cut weight anywhere I can. But I also have to have protection and armor. And it needs to look good for sponsors. So it'll be a balance. No bumpers is not an option and I don't like the tube look on 4th gens.

Per Ultra4: "Safety fuel cells are required for all vehicles. Auxiliary fuel tanks may be added. Auxiliary fuel tanks must also be safety fuel cells."

I'll be running a fuel cell - it's easier and cheaper than the alternative.



Nice! I've had two '87 SR5 Turbos as projects recently. You must be going for the Mod class. I need to know more about Atrac! Thanks for all the great feedback and keep it coming!

I see what you are doing now. I would not have ARB's in the front of an IFS rig, as that makes it impossible to steer when they are engaged. ( I actually have a front locker in an IFS 4runner, steering is close to impossible and may hold you up during a race) The Atrac system tries to brake wheels that are spinning with no traction using a jerking-type motion with the ABS to get you over obstacles. Less important in the rear since you will have a locker or spool, but the front still works with the system to enable you to steer and have computer assisted traction control. I have that setup on my 4th gen, with a Elocker in the rear and open front, there are few obstacles I can't get over, and some that would have caused me to die by rolling off a cliff if I had a front locker and was unable to steer. Also, don't forget about the high speed part of the race - the floating 4 link rear suspension in the 4th gen will really shine on the 90mph desert runs.

PM me about the Aux cooling system components.

 

[Charles4x4]

I see what you are doing now. I would not have ARB's in the front of an IFS rig, as that makes it impossible to steer when they are engaged. ( I actually have a front locker in an IFS 4runner, steering is close to impossible and may hold you up during a race) The Atrac system tries to brake wheels that are spinning with no traction using a jerking-type motion with the ABS to get you over obstacles. Less important in the rear since you will have a locker or spool, but the front still works with the system to enable you to steer and have computer assisted traction control. I have that setup on my 4th gen, with a Elocker in the rear and open front, there are few obstacles I can't get over, and some that would have caused me to die by rolling off a cliff if I had a front locker and was unable to steer. Also, don't forget about the high speed part of the race - the floating 4 link rear suspension in the 4th gen will really shine on the 90mph desert runs.

PM me about the Aux cooling system components.

Yes, I'm focused on KOH for the build, so desert will be the first challenge. And know that I primarily plan to use the ARB on the rock trails - a selectable locker is a must for JV. PM coming.

 

[Charles4x4]

Hey, my friend who is helping me on the engine wanted to see if we can get the v8 to 300 Hp. Can Headers, Exhaust, Intake, and a performance tune get us there?

What products do you recommend for each?

 

[duffdog]

Hey, my friend who is helping me on the engine wanted to see if we can get the v8 to 300 Hp. Can Headers, Exhaust, Intake, and a performance tune get us there?

What products do you recommend for each?

headers on the 2uz are proven to increase HP. I'm not so sure that you will be able to smog the truck ever again, however. What are the smog laws like where you live?

 

[Charles4x4]

headers on the 2uz are proven to increase HP. I'm not so sure that you will be able to smog the truck ever again, however. What are the smog laws like where you live?

How much HP increase? Thorley or something else?

I live in AL - no smog issues here.

 

[duffdog]

How much HP increase? Thorley or something else?

I live in AL - no smog issues here.

I would assume that if you did the whole setup - headers + crossover pipe delete + dual 2.5" exhaust + flowmaster 50 series you could easily get +30hp. If you are trying to go crazy, locating one of the original TRD 4.7l superchargers would net an additional +100hp no problem. Unfortunately, a new blower requires new h-beam rods to work properly.

 

[Charles4x4]

I would assume that if you did the whole setup - headers + crossover pipe delete + dual 2.5" exhaust + flowmaster 50 series you could easily get +30hp. If you are trying to go crazy, locating one of the original TRD 4.7l superchargers would net an additional +100hp no problem. Unfortunately, a new blower requires new h-beam rods to work properly.

No forced induction allowed in 4600.

Here's what I'm looking at:
- Doug Thorley Headers
- URD "Off-Road" Y-Pipe
- Magnaflow 15781 Stainless Steel 2.5" Single Cat-Back Exhaust System
- Afe POWER 54-82502 Magnum FORCE Stage-2 Si Pro 5R Cold Air Intake System with Prefilter
- Tuner - URD MAF Calibrator (Universal)

Any thoughts?

 

[Charles4x4]

For the tuner, would this work?

Unichip - 2006 Toyota Tundra tuning chip | car tuning

 

[duffdog]

For the tuner, would this work?

Unichip - 2006 Toyota Tundra tuning chip | car tuning

From my days on a dyno with Toyota trucks: NO computer tuner or intake of any type from any manufacturer makes more power on a stock engine than completely stock toyota parts with a stock Toyota filter. All of them are straight up snake oil junk that actually lowers your HP. I proved this on a dyno with my 3.4l tacoma 10 years ago. What those parts did do is make a bunch of noise and allow more dirt into the engine.

 

[Charles4x4]

From my days on a dyno with Toyota trucks: NO computer tuner or intake of any type from any manufacturer makes more power on a stock engine than completely stock toyota parts with a stock Toyota filter. All of them are straight up snake oil junk that actually lowers your HP. I proved this on a dyno with my 3.4l tacoma 10 years ago. What those parts did do is make a bunch of noise and allow more dirt into the engine.

Search somewhat agrees with you:

1) CAI is a waste of $:
http://www.toyota-4runner.org/4th-gen-t4rs/213418-cold-air-intake-worth-2.html

2) CAI is good:
http://www.toyota-4runner.org/4th-gen-t4rs/73859-best-performance-mods-2.html

So...which one is right on Afe intake?

What about the URD MAF Calibrator (Universal)?