LS Rx8 Project
06-21-2015, 04:03 PM
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LS Rx8 Project I have had this project underway for a while, and finally decided to post some pictures and information about it. I picked up an iron block 5.3 from a friend and had it sitting in my garage waiting for a vehicle.
I originally wanted to put it in a Nissan 240sx, but couldn't find any in the area that weren't drifted into walls or completely riced out. So, I decided to go for an Rx8. Picked up a base model 2004 automatic Rx8 as a roller.
Now that I had the motor and vehicle, I cleaned up the motor and painted it. Put a set of 862 ported and milled heads with brian tooley head springs. Ls1 intake, 224/228 cam for future boosted purposes, and fbody accessories.
I cut the pinch weld seam out of the engine bay and then stitch welded it. After that I extended the steering shaft and painted the bottom half of the engine bay with POR 15. I also spaced the steering rack down to clear the oil pan.
I couldn't get any answers or information from Hinson, so I ended up going with a universal "hot rod" motor mounts that were modified and welded to the stock k member.
I did a couple little things, like taking the fiber glass lining from the underside of the hood off for intake/throttle body clearance. I also eliminated the unneeded wires under the hood and traced them back to the main fuse box and terminated them.
Transmission is a TH400 I picked up at a local swap meet. Stock flywheel with the proper spacer. Convertor is a Yank 3600 stall convertor.
The battery was relocated to the trunk to make more room in the engine bay. Kill switch was installed and wiring was run to the front for the fuse box, alternator, and starter.
I adapted a stock 99 f body harness and ecu to work as a stand alone and then wired it into the car as well.
I originally wanted to put it in a Nissan 240sx, but couldn't find any in the area that weren't drifted into walls or completely riced out. So, I decided to go for an Rx8. Picked up a base model 2004 automatic Rx8 as a roller.
Now that I had the motor and vehicle, I cleaned up the motor and painted it. Put a set of 862 ported and milled heads with brian tooley head springs. Ls1 intake, 224/228 cam for future boosted purposes, and fbody accessories.
I cut the pinch weld seam out of the engine bay and then stitch welded it. After that I extended the steering shaft and painted the bottom half of the engine bay with POR 15. I also spaced the steering rack down to clear the oil pan.
I couldn't get any answers or information from Hinson, so I ended up going with a universal "hot rod" motor mounts that were modified and welded to the stock k member.
I did a couple little things, like taking the fiber glass lining from the underside of the hood off for intake/throttle body clearance. I also eliminated the unneeded wires under the hood and traced them back to the main fuse box and terminated them.
Transmission is a TH400 I picked up at a local swap meet. Stock flywheel with the proper spacer. Convertor is a Yank 3600 stall convertor.
The battery was relocated to the trunk to make more room in the engine bay. Kill switch was installed and wiring was run to the front for the fuse box, alternator, and starter.
I adapted a stock 99 f body harness and ecu to work as a stand alone and then wired it into the car as well.
06-21-2015, 04:04 PM
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Pulled the stock fuel tank because of the saddle design and had a fuel cell made and placed underneath the rear/trunk area. Fills through the stock filler neck, also using a stock filter/regulator out of a corvette. AEM 320 lph pump for E85. Also running 42 lb green top injectors and holly rails.
With fuel and power to the motor, I was able to throw some stock manifolds on it and start it! Link to the video of the first start:
http://vid1255.photobucket.com/album...psuw9yw5qp.mp4
I still have cooling system, brake lines, and exhaust to finish. Along with a driveshaft and few other things I'm sure. I'll try to keep this up to date as it comes along!
With fuel and power to the motor, I was able to throw some stock manifolds on it and start it! Link to the video of the first start:
http://vid1255.photobucket.com/album...psuw9yw5qp.mp4
I still have cooling system, brake lines, and exhaust to finish. Along with a driveshaft and few other things I'm sure. I'll try to keep this up to date as it comes along!
06-21-2015, 06:17 PM
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Even with the car I am amazed at how little I have spent on the swap so far. The drive shaft is going to be pricey I'm sure though, not looking forward to that! And yes, that is my husband's fc hiding back there 
06-21-2015, 07:06 PM
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Tell you the truth you may find a driveshaft over on norotors. These swaps are starting to gain popularity. Even if you don't locate one I'm sure a new one won't be too bad. When your car is all said and done it should be a pretty well rounded car. It will definitely catch some folks off guard.
06-21-2015, 07:07 PM
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Tell you the truth you may find a driveshaft over on norotors. These swaps are starting to gain popularity. Even if you don't locate one I'm sure a new one won't be too bad. When your car is all said and done it should be a pretty well rounded car. It will definitely catch some folks off guard.
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06-22-2015, 12:05 AM
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Rear end is on the list of things to figure out, but it'll most likely be an 8.8, it's the only thing that makes sense to me so far. I want to be able to drive it around town to shows and things occassionally, but be able to take it to the track and not completely embarrass myself. At this point, my goal is to just get it driving and then I can figure out where to go from there
06-22-2015, 06:58 AM
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Well you quite possibly picked the worst chassis to drag. Its pretty light and very stiff though so you may get it down. Im impressed with the quality of the work. I would highly recommend you drill and stud weld the steering shaft. I just drilled and used 8mm bolts in mine. Ground off the heads/threads and welded the stub.
06-22-2015, 10:38 AM
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It was mainly for hood clearance and being where it attached to the K member along with how the mount kit was fabbed before it was sent to us. The stock K member had to be modified to get the engine far enough forward. To put it simple, where the mounts welded to the K member was the most logical place for them to fasten to based on how the K member was shapped. By pointng them down, it gave her the much needed hood clearance from the motor/intake/TB being so tall. . Hopefully thats not to confusing.
06-22-2015, 10:45 AM
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Well you quite possibly picked the worst chassis to drag. Its pretty light and very stiff though so you may get it down. Im impressed with the quality of the work. I would highly recommend you drill and stud weld the steering shaft. I just drilled and used 8mm bolts in mine. Ground off the heads/threads and welded the stub.
06-22-2015, 01:02 PM
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It was mainly for hood clearance and being where it attached to the K member along with how the mount kit was fabbed before it was sent to us. The stock K member had to be modified to get the engine far enough forward. To put it simple, where the mounts welded to the K member was the most logical place for them to fasten to based on how the K member was shapped. By pointng them down, it gave her the much needed hood clearance from the motor/intake/TB being so tall. . Hopefully thats not to confusing.
As far as engine bays go the RX8 is very roomy. Not like my 87 chevy but pretty roomy. The LS1 intake has the smallest plenum so height shouldnt be a concern. My subframe is untouched aside from welding on the pedestals. If the motor is far enough forward that the oil pan interferes with the subframe then id hate to think about how bad the handling will be. I have enough room for a E Force roots supercharger and my pan is inches behind the subframe. Add to the geometry the iron block and huge auto. Dont mistake what im saying for criticism. Im loving that the RX8 is gaining so much traction as a swap candidate. Its just wierd seeing them with Iron motors and autos. Kinda the opposite of what they represent. Either way great build and keep it up.
06-22-2015, 01:20 PM
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As far as engine bays go the RX8 is very roomy. Not like my 87 chevy but pretty roomy. The LS1 intake has the smallest plenum so height shouldnt be a concern. My subframe is untouched aside from welding on the pedestals. If the motor is far enough forward that the oil pan interferes with the subframe then id hate to think about how bad the handling will be. I have enough room for a E Force roots supercharger and my pan is inches behind the subframe. Add to the geometry the iron block and huge auto. Dont mistake what im saying for criticism. Im loving that the RX8 is gaining so much traction as a swap candidate. Its just wierd seeing them with Iron motors and autos. Kinda the opposite of what they represent. Either way great build and keep it up.
As far as the motor being forward, the back of the manifold is right at the firewall. There is no possible way to move the motor back any farther in the engine bay. As far as the oil pan interfering with the subframe it does not. its as low and far back as physically possible without modifying the subframe - except to weld on the the mounts. As far as the "heavy" auto goes - a T56 weighs in at 125 lbs if i remember correctly. A TH400 like in this car weighs in at 135 lbs. If that 10lbs breaks the build then so be it.
This build is the opposite of what the RX8 represents, i will give you that. However this build is hers and full of her decisions. If she wanted a car for a road cource or auto cross then this would be totally the wrong car. Now if she wanted a car that was somewhat quick, would hold up to boost (that explains the iron block), would do a decent quarter mile time, and get attention at shows, then she has the right car.
That being said, your saying that the car would be better as an aluminum blocked manual car. I would kindly disagree with what she has in mind and her intentions with it.
06-22-2015, 01:30 PM
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Th400 with converter, fluid, lines, and cooler weighs much more than a T56 and clutchclutch. As for the iron block strength, the strength is in the piston. Not so much the block. Ive never heard of a block failing before a piston or head sealing failure.
06-22-2015, 01:41 PM
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A T56 has all of those things as well. So your talking weight difference of a clutch to converter and the 10 lbs of the trans.
The auto helps in straight line performance as well. Again, i get it if an iron block auto car is not your cup of tea.
IF weight was the main concern then everyone would build an LS1 foxbody. Price and availiblity is a major plus of the iron blocks as well. So, if this build ever gets to the point of pushing what a stock block can hold, then the iron blocks will be alot less expensive to replace and to find a new/used shortblock to throw in it.
The auto helps in straight line performance as well. Again, i get it if an iron block auto car is not your cup of tea.
IF weight was the main concern then everyone would build an LS1 foxbody. Price and availiblity is a major plus of the iron blocks as well. So, if this build ever gets to the point of pushing what a stock block can hold, then the iron blocks will be alot less expensive to replace and to find a new/used shortblock to throw in it.
06-22-2015, 01:45 PM
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However i would be curious to know what yours weighs compared to hers. Do you have a weight on yours? Maybe you can throw it on a set of scales before you get it sold. When her build is done, she can do the same. It would be interesting to see the weight difference along with the front to rear ratio.