4400 IFS Rear Engine Ultra4 Build

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UPDATE: The build was originally intended to be a 4800 Solid Axle car, this has since changed. The build changes direction to IFS on page 3.



I'm too excited right now so figured I would start a (perhaps) premature build thread so I can lay out my thoughts. I've been looking at the Rock Lizard chassis's out of SLC and they are super cheap and light weight and tiny, which got me thinking: I have a wrecked 1st gen tacoma that NO ONE will buy (even for $400), and I have a ton of racecar parts from my 4500 Land Cruiser build last year.... so essentially, with the exception of a good front axle, I have a full drivetrain, shocks, fuel system, cooling system, etc. So that's kind of $1500 for an already welded chassis plus a front axle and that's a cheap and sick little buggy.... Here are some pics from FaBn801 who makes the Rock Lizards:

mX24LO1h.jpg


KpNC6GKh.jpg


Now my initial thought was just do a fun little crawler, maybe I could even build it before KOH so I have something fun to take down there... but then I talked to my dad and he formally put it in my mind that if I'm building a tube buggy why not build it to race? And that's where the POSSIBLE idea of racing it in 4800 came along.

So regardless what happens, I'm pretty set on getting one of them since the prices go up at the beginning of the year. I even went ahead and cleared out a section of the shop and stripped the parts off the 80 (will either chop up or scrap that chassis most likely) and started laying everything out in preparation for when I actually buy the chassis.

WPiRsp0h.jpg


Good bye 4508? :'(

NwvSQ1qh.jpg
 
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Now into my thoughts! So Ultra4 has weight/cage size requirements, I've already talked to Fabn801 and he says it's a 1.75" sub frame with 1.5" everything else. I'm not sure what constituents a sub frame but I'm guessing it's just the floor pan essentially where the links and maybe drivetrain bolt up. So that effectively means I would need to meet the 1.5" weight requirement which is sub-3200lbs. Fabn801 says his personal buggy with I believe a 22r is 2000lbs fully loaded which gives me hope. He has said he can do some one off stuff, but I more of inquired about removing things (like the front and rear V brace I'm not a fan of the size or setup, so he said he could just not weld those in). So whether he can upgrade the whole chassis to all 1.75" and bump it to a 4400lb limit, I do not know.

So that means I have to be 3200lbs without me or a codriver and "wet" and "loaded", assuming a totally stock chassis. He says the chassis weighs 250lbs, which right off the bat is 500+ lbs less than my FJ80 chassis. What I really like about this whole light weight concept is with the 80, I was all about big axles and big horsepower to do what I wanted (or that was my future vision), but if you weigh 3000lbs, you don't need a lot of power and you don't need big axles to have a reliable and quick buggy. So que the build ideas:

LlduKoZh.jpg


As I said I have a lot of gear already, so using all the current stuff that's collecting dust and a few (possible) liberties this is my plan:

Diamond front housing with a LP 9.5" and RCVs and stock toyota outers/brakes/hubs/etc. (I have all this but I have a bent housing, this would also allow me to go driver drop on the axle)
3rz with auto and J shift
Stock FZJ80 full float rear with Nitro Chromoly shafts
14" 2.5 ADS coilovers
2.0 ADS bumps
32gal Jaz fuel cell
TK1 racing sway bar
37 Toyos on 17 Trail Readys
Rear mount FJ80 radiator with Taurus fan
PRP seats and harnesses
PCI radio/intercom/forced air/etc.
Baja Designs front lights and chase lights
Possibly/most likely go to full hydro and a 4 link front since why not

So I'd have a ~150hp setup in a ~3000lb buggy with all FZJ axles essentially and chromos and 37s and some decent shocks which I'd probably swap out in the future (4800 is only allowed single shock).

While taking the 80 chassis roller apart and moving the 3rz around I used a crane scale I bought off amazon to weigh everything:

Stock front housing without shafts or 3rd member is 246lbs
jpLUy0Yh.jpg


Stock rear fully loaded is 315lbs (so realistically this is what the front would weigh too)
GF91nQih.jpg


And the 3rz and auto and j shift comes in at 668lbs
6uPZwtMh.jpg


So then adding in coilovers and the Rock Lizard chassis gives about 1500lbs left of stuff, that has to include tires, seats, fuel system, cooling system, links, radios, etc. PLUS the stock chassis doesn't have bumpers so I would have to fabricate a front and rear extension, nothing complicated but something that would poke out an inch or two past the tires as a "bumper" and that will add more weight, especially since I'll have to tuck up the fuel cell and potentially a spare in the back.

So is 3200lbs realistic? I'm not sure.... And that's for a stock chassis, assuming he can bump all the tubing to 1.75" then this would easily come in under 4400lbs. I'm going to draw up a spreadsheet and weigh everything I have and get an accurate idea of just how heavy all this is, since I know my tires are around 125lbs so that right there is 500lbs without a spare so only 1000lbs left for the entire interior/cooling/fuel system--which maybe that's plenty of margin, but maybe not... (again assuming a 1.5" primary structure).

On the one hand I'm like do I really want to push myself to that limit and do another racecar? And on the other hand I'm like, if I'm building a buggy why not? May as well use all the gear I have sitting here. I was hoping I could do this build in about 2 months since I still need to pump out the SRQ 4600 cage, but as time goes on I doubt that is realistic, maybe as just a crawler but not as a full fledged racecar and I want to do this right and make it nice (like fully paint the bare chassis with nothing in the way) and not do a rushed build. Anyways, regardless what path this ultimately takes, I figured it would be fun to post about and keep a log of my thoughts :)
 

AssBurns

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Yeah I am liking where this is going! I’d definitely say weigh everything and see how much margin you realistically have there. So many little things can add up quickly. It would be pretty badass to have a lightweight race buggy.
So if you end up having to bump up to the 4400lb limit, what are the engine requirements? I’ve never looked into the 4800 class, so I don’t really know anything about it. Can you just ditch the whole 4508 build and make this a lighter weight LS build and keep it under 4400lbs? Running single shocks does have quite the limit, so is running an LS motor realistic if you go that route?

I guess you gotta weigh out the pros and cons of this class, and really see how lightweight you can build it to make it realistic. Definitely looking forward to seeing what you come up with :popcorn2:
 
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Yeah I am liking where this is going! I’d definitely say weigh everything and see how much margin you realistically have there. So many little things can add up quickly. It would be pretty badass to have a lightweight race buggy.
So if you end up having to bump up to the 4400lb limit, what are the engine requirements? I’ve never looked into the 4800 class, so I don’t really know anything about it. Can you just ditch the whole 4508 build and make this a lighter weight LS build and keep it under 4400lbs? Running single shocks does have quite the limit, so is running an LS motor realistic if you go that route?

I guess you gotta weigh out the pros and cons of this class, and really see how lightweight you can build it to make it realistic. Definitely looking forward to seeing what you come up with :popcorn2:

So the weight limit purely controls the primary cage tube size and nothing else, so if a LS didn't push it over the 3200lbs limit for 1.5" tube then nothing on the chassis would have to change (theoretically). With the 4800 class, like with 4500, the drivetrain is totally unlimited. The only limits with 4800 is single shock, 37s, and solid axle (so trailing arms with a 16" 3.5 IBP coilover is totally allowable). It's meant to be a class for older unlimited cars where they just down size tires and pull the bypasses and are ready to go. And I would totally see about going LS from the get go, but this is primarily meant to be as budget oriented (to an extent) as I can, and since I have this entire 3rz sitting here with no interest and have the whole harness and gauges and everything it makes sense. Plus in the future I might get the turbo kit that Matt at SRQ is selling, which then you're looking at 250-300whp (apparently) in a 3000lbs buggy which should get up and move. That's starting to get comparable to the power/weight of bigger buggies running a 400-500hp LS, while still keeping stresses everywhere else low and having a very cheap engine by comparison---at least that's what I'd like to think, we'll see how it actually stacks up once I have it running and feel it out.
 

AssBurns

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So the weight limit purely controls the primary cage tube size and nothing else, so if a LS didn't push it over the 3200lbs limit for 1.5" tube then nothing on the chassis would have to change (theoretically). With the 4800 class, like with 4500, the drivetrain is totally unlimited. The only limits with 4800 is single shock, 37s, and solid axle (so trailing arms with a 16" 3.5 IBP coilover is totally allowable). It's meant to be a class for older unlimited cars where they just down size tires and pull the bypasses and are ready to go. And I would totally see about going LS from the get go, but this is primarily meant to be as budget oriented (to an extent) as I can, and since I have this entire 3rz sitting here with no interest and have the whole harness and gauges and everything it makes sense. Plus in the future I might get the turbo kit that Matt at SRQ is selling, which then you're looking at 250-300whp (apparently) in a 3000lbs buggy which should get up and move. That's starting to get comparable to the power/weight of bigger buggies running a 400-500hp LS, while still keeping stresses everywhere else low and having a very cheap engine by comparison---at least that's what I'd like to think, we'll see how it actually stacks up once I have it running and feel it out.
I really like the idea of keeping it light weight, with huge IBP coilovers and a turbo. Maybe @madtaco461 can chime in on the turbo’d 3rz. He’s been running one in his LT 5 lug Tacoma for a while. He is working on making his push out quite a bit of hp with increased boost soon, if I remember correctly.
 

4runner DOA

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Mkiii tdi engine? You can get 200hp/torque for about 2k. That's chip, turbo, and nozzles. Plus you'd get 40+ mpg. Haha.
 

4runner DOA

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Maybe more at the cost of mpg with tuning, that's just what I've seen for the standard street tdi.
 
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So I'm getting the turbo kit from Matt at SRQ, from my reading just running a different head gasket and swapping out head studs an otherwise stock 3rz can push around 15psi and 300+ whp pretty reliably. He's sending me the turbo after the hurricane passes, and that way once the chassis arrives I can test fit the engine with the turbo. I'm also pretty set now on having this be a longer build, and shoot to have it done around May (with 1-2 months lost for other projects and KOH) and then I can really dial it in and make it nice and maybe powdercoat the whole bare chassis.

Fabn801 just told me that they can probably do the whole main cage structure in 1.75" tube which would be awesome, bumps weight a bit but that also allows up to a 4400lb curb weight for racing.

I'm also now planning to run trailing arms from the get go, the weld it kit from Ruff stuff without heims is under $400 and only weighs 40lbs per arm!! So I'm thinking get that for the rear, then get some summit machine aluminum links for the front end, and run summit machine flex joints all around which are supposed to be the tits as far as durability and longevity go. The normal ruffstuff trailing arm kit uses a bushing front, I would swap that out for a welded summit joint up front and a threaded summit joint out back. Since I can only run single shock, that then gives me the option on the trailing arms of a 1.8:1 or 1.4:1 shock ratio, so even with my 14s that's a minimum ~20" of pure travel out back which isn't too shabby! I'll most likely upgrade to 3.0 or 3.5 IBPs too.
 

madtaco461

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The Toyota auto transmission won't be too happy with 300whp even with upgrading the valve body and torque converter. Just going off what I have read.

I had to upgrade to an r series manual transmission. I picked a r155 for my truck last year because the w series just can't hack the torque. I did kick the clutch often to help low rpm spool up.
 
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The Toyota auto transmission won't be too happy with 300whp even with upgrading the valve body and torque converter. Just going off what I have read.

I had to upgrade to an r series manual transmission. I picked a r155 for my truck last year because the w series just can't hack the torque. I did kick the clutch often to help low rpm spool up.

I was figuring that'd be the case, there's a R150F for $250 that popped up nearby I was debating getting but probably just hang on for now. The turbo will be the last thing to go on after I know the engine is running right after I slim down the stock harness.
 

madtaco461

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I was figuring that'd be the case, there's a R150F for $250 that popped up nearby I was debating getting but probably just hang on for now. The turbo will be the last thing to go on after I know the engine is running right after I slim down the stock harness.

That's a good deal. Just keep an eye out for a bell housing too. There isn't too many wires to make an 2/3rz run good.
 
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Well I finally got paid from one of my customers, so I talked to Fabn801 today and he said he can do the whole cage out of 1.5/1.75 tubing. So essentially his current chassis he has will just have all the tubes bumped one size to a max of 1.75. If you follow his facebook or instagram he has some CAD models which I'm pretty sure are my chassis.... Over all cost is a bit more than I was expecting, but still acceptable. It's a hair over $2k for the weld it kit, plus shipping which is under $300 since they're based out of Salt Lake City. $2k was my mental "worse case" of what the increased size would cost, not sure why less than 20% more steel is a 50% price increase, but it's still like half the price of any other chassis out there. Waiting to get the invoice from him and pay him, but otherwise I told him let's do it!

I also ordered a 1.75" die for my JD2 bender since as said, I will have to fabricate front and rear bumpers and seems like doing it out of 1.75" to match the chassis is the most straight forward way to go. I was going to order a Diamond housing for the front but my girlfriend said I need to finish the SRQ 4600 cage first before I start buying more parts, so for now we wait on the chassis and hopefully I can get the 4600 done and out fast to get this thing going!
 

Hank

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Well I finally got paid from one of my customers, so I talked to Fabn801 today and he said he can do the whole cage out of 1.5/1.75 tubing. So essentially his current chassis he has will just have all the tubes bumped one size to a max of 1.75. If you follow his facebook or instagram he has some CAD models which I'm pretty sure are my chassis.... Over all cost is a bit more than I was expecting, but still acceptable. It's a hair over $2k for the weld it kit, plus shipping which is under $300 since they're based out of Salt Lake City. $2k was my mental "worse case" of what the increased size would cost, not sure why less than 20% more steel is a 50% price increase, but it's still like half the price of any other chassis out there. Waiting to get the invoice from him and pay him, but otherwise I told him let's do it!

I also ordered a 1.75" die for my JD2 bender since as said, I will have to fabricate front and rear bumpers and seems like doing it out of 1.75" to match the chassis is the most straight forward way to go. I was going to order a Diamond housing for the front but my girlfriend said I need to finish the SRQ 4600 cage first before I start buying more parts, so for now we wait on the chassis and hopefully I can get the 4600 done and out fast to get this thing going!

I'm constantly driving between my house in Northern Utah to SoCal. Usually in my F150. I don't mind throwing hauling it down to southern Utah as I'm driving through. Just if the shipping is outrageous.
 
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I'm constantly driving between my house in Northern Utah to SoCal. Usually in my F150. I don't mind throwing hauling it down to southern Utah as I'm driving through. Just if the shipping is outrageous.


I appreciate the offer!! The shipping actually isn't bad, they quoted me at $275 for shipping or said they could just drive it down for a little less. If you're ever in Cedar City let me know, my shop is less than a half mile off the 2nd exit towards the West.
 

Hank

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I appreciate the offer!! The shipping actually isn't bad, they quoted me at $275 for shipping or said they could just drive it down for a little less. If you're ever in Cedar City let me know, my shop is less than a half mile off the 2nd exit towards the West.

Sweet. I'm down that way pretty frequently. I'll be driving through on the 23rd next. and most likely will be towing a empty flat bed trailer as well. so really not a big deal to swing by their shop and drop off in Cedar.

Then again in between thanksgiving and Christmas.
 
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