I thoroughly enjoyed reading through your build thread. Nice work that was well thought out.

Thanks man! Appreciate the kind words!

Alright guys,

Managed to get about 16 hours into the car over the weekend, even though it doesnt seem like alot, these footings are very time consuming!

Footings are all tacked into place now, I just need to make a few reinforcements to them. Hoping to grab some tube tomorrow to start work on the main hoop, will just chip away as I go.

First plate getting fit in

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getting closer

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Front mounting box (I have it reinforced inside)

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I think I am going to finish weld them once the tube is in place justttttt in case lol

Safety first.... :yelrotflm

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And, finally got to actually mockup my viper brakes! :bowdown::bowdown::bowdown:

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Size comparison!

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Cool shot my buddy got while I was tacking the front mounting plates

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More this week hopefully! :Peace:

Do you guys ever rosette weld your fish plates too?

Im not sure that is actually legal in the race classes. I havent seen rosette welds in mouting plates before, I gotta assume there is a reason for that. I am not to grind on the tubes or plates other then for preperation of where it will be welded.

I just looked up some Pikes Peak and Rally requirements, all I saw was a certain thickness, as large an area as possible and routed to the main structure.

I have seen once before in a similar situation as your first/second picture might be. A side impact to the B-Pillar caused the plate to basically tear off. They had it welded along the pinch seam and the piece towards the front of your car where you can see the material is doubled up there. They had it welded just to the top part and it tore that piece right off. Looks like yours will be welded to both sections though. Also it depends where your tube placement actually is.


I have never seen rosettes, aside from in the off road world and I know from experience trees don't move other than when they jump right out in front of you :yelrotflm


https://s3.postimg.org/5l9h97lab/sdf.jpg

Appreciate the input! I am definitely learning here!

Would you think it may be beneficial, to run a weld down the top of the pinch where the door seals go over (where your left pointing arrow is), and continue the weld that catches both seams, down into the foot well? That way I can be a little more certain it wouldnt be able to tear the top layer off.

I know the SCCA rules are 0.080" thick mounting plates, I have mine at .120" so I am a bit over for that aspect.

Anytime man, your work is definitely top notch though, very impressive. When I did my Cherokee buggy I welded the pinch seam just like you said, maybe no major difference, but I enjoyed the piece of mind. Yeah I would feel safer with .120 plate too.

I am not an expert, but I have walked away without a scratch from a backflip onto concrete, a 20 foot endo onto my roof, and 3 complete barrel rolls through some trees hahaha.


Looking forward to see how the cage comes out, I am sure it will give me some good ideas hahaha

Too many tack welds buddy. How are you going to remove the front boxes and base plates to drop the cage and weld the tops? By the way, I like your front boxes design, looks very familiar :biggthump

Shit!!! I didnt think about that haha!

I have been thinking about removing the roof skin both to assist with accessing the top of the cage for welding, but also for closing up the sun roof. Was thinking of making a mold and making up a carbon roof skin just for another learning project to add into the mix and that the roof is a rather simple shape to replicate.

Maybe just forced my hand and now I will have to :yelrotflm

Really appreciate the input guys! I am learning tons as I go, have no formal training on any fabrication, welding or roll cage design, just tryin to do lots of research, watch videos, look at what others have done etc. I am definitely having alot of fun with it as I am going though!

Swap
 

What all engines are compatible with my 2009 RX8

Every engine, the RX-8 is what is known as a universal chassis so any modern engine will bolt right in.

Bahaha. Love it!

Bolting in is just one part of the job. Getting the engine and car systems to work together is the lion's share of the work.

A 2009 car is presumably an S2, with systems that are harder to integrate than those in S1s.

Hey Chez, this thread has been a great read!! It's really a great primer for others who are thinking about swapping in a V8 or anything else really because the RX8 was designed for such a proportionally different motor. It's great to see all the little things you have, and are still running into along the way and I thank you for documenting it so extensively!

I've got to say though when I got to the part about you switching out the LS for a turbo I4 it was a bit of a shock! I understand myself about how hard it is to decide on which motor to swap into the 8, but to swap a swap is almost crazy lol!! At least you will have an awesome perspective after dealing with both setups.

The question I have is do you think the I4 (DOHC or SOHC?) with turbo will make an improvement in handling vs the LS V8? The RX8 is all about weight management and I understand the reason it does so well is the 50/50 balance, and focusing the motors weight as low and as far back behind the front wheels as possible. The LS actually has a similar weight advantage compared to most other V8s and maybe even inline engines too. Its relatively light, the V design brings the weight of pistons, rods, and heads a little lower, and what makes the LS unique compared to most modern V8s that I'm aware of is the single cam valve operation (AKA pushrod design) that places the cam lower between the V instead of on top.

Compared to an I4 that has two cams on top and is probably taller (higher COG) and even a little longer than the LS, do you expect the total weight savings to be better for turn-in and body roll? I wonder if it might not be much different. Another thing to note is that every I4 swap I've seen requires the firewall to be cut away for the best fitment...

Can you tell I've thought about this stuff a lot!? lol! I'd be happy to hear your take on this.

I'm fitting the same engine in mine. The way I've done it required a lot of cutting into the firewall, but the gain in that is the engine sits behind the strut tops.

Cheers John

I completely understand the change from LS to 4 cylinder, yes an LS is quite light for a V8, but 50lbs in a race car is a fair amount...50lbs in the wrong area is a lot. I changed my game plan for the same reason!


Nothing really unique about the LS motors, it is the same basic design GM has always used. The big LS thing is their simplicity, the commonality of parts between motors, how stiff and durable the bottom end is...the way the mains are bolted in is an extremely sturdy and effective design. The biggest improvement I see over the older LT series V8s are the head designs, the LS heads and top end flow incredibly.


One thing when keeping the same design over the years is you can really fine tune everything and it really shows. I mean one of the fastest cars in the world uses a twin turbo LS :bowdown:

In engineering, simplicity almost always wins. And the modern V8s try to be too fancy, the Coyote Motor has enough timing chains to circle the motor 2 or 3 times I bet.

Alright, Guess its time to do another little update.

So, first big update, once AGAIN, I have changed engine plans lol.

A few months ago I started a new job working for GM again, and I was thinking of mothballing the RX8 and buying a C6 Corvette to work with since it made more sense.

Obviously, that has yet to happen, and I couldn't bring myself to give up on the RX8 for the 5th time, so I started thinking about which GM engine I could use to power it and tie it closer to my work. I first was thinking the new 2.0L LTG engine, but it is rather expensive given its power output.

I just didn't want to be "another" LS swap anymore, so I asked our shop foreman one day if he had any ideas for a GM engine.... and he mentioned belief that the new LF4 Twin turbo 3.6L shares many parts with its LLT/LFX little bother. This sparked some obsessive research.... and the rest is history.

Anyways, to stay in chronological order, here is some updates on the cage fabrication:

Managed to get the main hoop bent without too much event:

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I am working on removing the roof skin to replace it with a non sunroof unit. So far, I am an expert on the wrong way to remove the rear glass:

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Started work on the rear tubes:

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When you have friends who pretty much have infinite debt to you... put them to work :rollingla :

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Some more progress on the rear bars, also windshield out!

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Cage tucks pretty tight into the roof! And when you have 22c days in February in Canada... Doors open!!!

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Took a weekend off(?) to go down to Washing DC for the Keystone Big show, and spend some money! :Peace:

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On friday the journey for Twin Turbo ATS-V power officially began... :Wconfused:Wconfused:Wconfused

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Not wasting time, had to see how it fit! Quickly became obvious that notching the firewall will be required to get the motor as far back as I want. The HPFP mounts to the back of the drivers head which is hella annoying.

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LF4 Engine systems:

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Tucked back better now! So much space for activities! :beer05:

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That concludes the current position. On order to arrive over the next week or so:

LF4 Intercooled intake manifold
Both turbochargers
Oil Pan
Oil Cooler block
Camaro Steering rack
Camaro Power steering pump
TR6060 from ATS-V

Bunch of other things on the way too, but those are all anyone cares about LOL.

Hoping to have more updates by end of next weekend including engine mounting if I am lucky!!

Lookin great! The LF3/4 looks like a great choice for the RX8. The narrow v angle looks it fits great, it makes as much or more power than a LS3 while being smaller displacement. I'm looking forward to seeing you finish.
Do you think it'll end up fitting with the stock rack in the stock location?

Definitely!! I didnt realize how much potential these motors had, though admittedly, the LF3/4 engines have brought a whole new level, especially in OEM available parts.

The stock rack is a no go unless I cut even further into the firewall. I don't want it anyways so I dont feel too bad lol. For most others doing this swap, the biggest down fall as far as positioning goes, is the HPFP. There engine would be similarly located as far as steering and sway bar is concerned, to the V8.

I will have my oil pan, oil filter adapter, and a few other bits in probably in a day or so, along with a transmission so that I can get to work on the mounts, and then keep going with sub systems.

Yay, Parts arrivals!!


I cant remember the last time an OEM part has got me as excited as this intake manifold does! This setup is truly brilliant, and is the Gen2 execution of GM's LF3/4 intercooled intake manifold. While this intake manifold (LGW 2017+) is not a direct fit to the Gen 3 High Feature V6, the improvements seen by this manifold over its all aluminum predecessor, is worth the effort of producing a custom lower intake manifold.


This intake manifold is for the LGW 3.0L Twin Turbo, new for 2017 engine. Unfortunately the Gen4 V6 engines share almost nothing as far as part numbers go, however their dimensionally very similar, and it is definitely possible to make this work! Nothing like a 12" distance from turbo outlet to throttle body!


Attachment 217236




Transmission also showed up, this is a used unit from a 2010 Camaro. Its the Aisin AY6, and I know it is not rated for what I am planning to put it through, but it is increadibly cheap ( sub $500usd) and maybe it will surprise me? lol


The new ATS-V has a TR6060 in it with a unique bellhousing to fit it to the HFV6 family, however GM only is offering them on an exchange basis at the moment. I figure if I split this one apart, then I have better grounds to call my reps at GM and beg for them to sell me one LOL!


The shifter linkage positions it way too far back at the moment so I will fabricate a new shifter linkage system but that is easy stuff!


Attachment 217237


Hopefully some pictures of it all mounted by the end of the weekend :)

Managed to make a bit more progress over the weekend!


Very excited to say the engine is officially mounted! That being said, it is just tacked together right now, I am waiting for turbo's to arrive to verify their fit around the mounts before I finish boxing them up.


I opted to go with solid engine mounts, and I know its going to be a bit of a vibration nightmare, but the benefit of making the engine a stressed member of the chassis and improving stiffness of the subframe after having to notch into it, is worth it. It also simplified the engine mounting, as I need to pick up a low spot on the engine block to be sure the mounting fits underneath the turbo's.


Firewall modifications are significantly more then I would have liked, but they are not to the point where the firewall has been completely reconstructed, nor is it cut as far back as some have to fit a 4 cylinder to the stock RX8 transmission.


Attachment 217226


The meat & potatoes :eyetwitch


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Tucks in pretty nicely! I am pretty content with its positioning, though the oil pan will need to be addressed as its currently sitting lower then the bottom of the subframe.


Attachment 217228


Of course its gotta look pretty under there! :) ATS-V Engine cover!


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Welp, I did a few more things to it in the last week!

The LGW intake manifold design has begun, and it is going to be a rather complex piece to say the least, though the outcome will be amazing. Kind of sad to say, this originally began with hope that it would be cheaper than a new LS3, however that is becoming increasingly apparent that will not be the case LOL.

It looks taller than it is, and fits well under the stock hood.

Attachment 217212

Made some progress on the fit of the coolers. The center will be a intercooler heat exchanger and the rad, and each outboard cooler is also intercooler heat exchangers for a triple exchanger setup to get the most heat out I possibly can. The oil coolers will have some clever ducting from the bumper to retain the OEM ones.

Attachment 217213

The nice thing about not having a windshield in it :rollingla

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It almost seems like I have lots to space to play with. However, the sides of the motor are absolutely crammed since the turbos bolt to the heads, and it has made the design of the engine mounts a significantly more complex setup than the V8 N/A needed :boring:

Attachment 217215

And then I finally got to do some cardboard mockup for the reason I wanted the whole front end open! I need to do some CFD work to determine the best shape for it, but I am really excited for this setup!

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One of my best friends Rob who runs @basicbuilds on Instagram and Facebook came over on friday to work his camera magic. The results are nothing less than amazing!

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Yay progress!


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