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Snailed

240Z - Snailed style

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Snailed    3

I have been working on the front of the car lately. Mostly getting the rails tied into the upper parts of the engine bay along with reinforcing the bottom of the door hinge pillar so I can get that tied in across the foot box area. I'll get some pictures up soon of this. Once I'm done here, it's time to position the engine & transmission and build or modify the tunnel.

 

It seemed like a good time to order some motivational parts so I picked out the turbo I want and two Tial MVS wastegates. The turbo is a Borg Warner Airwerks S200SX. The 76mm extended tip compressor flows 60lbs/min. in this 4" inlet housing. The turbine is cast inconel wheel in a 1.22a/r twinscroll housing. This will go on a divided manifold and should spool at least as good as a small GT30R but make more power...and it's a journal bearing chra so there are no coolant lines. I want it to look nice, so less plumbing is always good.

 

I'm thinking about making the manifold with 1.4" ID runners instead of the usual 1.7" to promote fast response.  I want lots of area under the curve so it feels fast without completly wringing the engine out all the time.

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Snailed    3

Thanks guys!

 

     So those cheap steel hubs I was looking at, the MBM ones, are about 6.5lbs EACH. That is a pile of unsprung weight.  I got a good, used RX7 hub for about $30, which is aluminum and closer to 3.5 lbs including studs and bearing races (the MBM had neither installed). The inner bearing is a little bigger than the Mustang one, which is nice for durability. So my idea was to fit a slightly larger OD outer bearing by turning about .020" off the ID of the hub and pressing in a new race and then making a sleeve to adapt the large RX7 bearing to the Mustang spindle. But this didn't work out, the distance between the inner edges of the bearings is too close together on the RX7 hubs. I guess in a way I just don't like the idea of using off the shelf Wilwood hubs, and I'm cheap (see rear suspension). Like the spindles, they sort of make the best, reasonably price option and at 3.1 lbs bare, they are as light and a lot stronger than any OEM hubs I could adapt. And it will save me a lot of time messing with bearings...so, I'm going the boring route and just ordering hubs I think.

 

   Here are couple more shots of the front. I used a little piece of 16g to reinforce where the upper rail meets the 1" tubing. I put a little drain hole to get rid of any moisture that might collect from the fresh air ducts. You can also see the very small patch on the bottom of the inner fender.

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Snailed    3

I finally made some time to work on this. I got the large patch piece on the inner fender welded in on top and tacked to the rail. I'm leaving the center section unwelded because I think I'll probably remove or reshape the strut towers once I get the front suspension fabricated and installed.

 

I used a torch and scraped a lot of undercoating off the top and bottom of the former battery tray area to see how I far I need to go with my patching there. I had drilled out the spot welds and removed the tray a while ago so it was pretty easy to see where the rusted metal was once the tar was scraped off.  I'm going to have to split two seams here to get to the rust I can see. I have no doubt that I'll find more than I can see from the outside...

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Edited by Snailed

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Snailed    3

It's freezing outside and I had the day off so I put a few hours into the 240. I got all the ugly metal cut out and fabricated a patch for the firewall. I wish I had the engine mounted already because the tunnel was in my way the whole time and I may end up removing it anyway. The panel stayed pretty straight and it's TIG welded so I probably only have ten to fifteen minutes dressing the weld and metal finishing it...and about three hours getting it to that point haha

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Snailed    3

Very nice job on the metal work, awesome build

Thanks so much for the encouragement.

 

So I got the battery tray patch made and welded in today. I made it out of one piece and the amount of shrinking was a little excessive on one corner but overall it wasn't a bad piece to make. It's not exactly original. I took out that weird little jog where it meets the firewall because it was easier and I think it looks better being smooth. I snapped a bunch of pictures too in case anyone wants to see one way to do it.

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Edited by Snailed

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richracing    2

About the turbo,  I was wondering if there was a method behind the madness?  Madness being the 1.22 a/r...  I was always under the impression that a bigger compressor/ smaller exhaust side promoted faster spool response.  That t4 hot side looks massive compared to the compressor.  Will you be using a quick spool valve?  Amazing fabrication btw.  I look forward to seeing the progression!

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Snailed    3

Thanks guys

 

Yeah, generally bigger turbos will come on later and make more power...the turbine a/r doesn't really tell you anything though. You could have a 1.22 a/r housing maxing out at 250hp or 1500hp.Mine just looks so big because it's twin scroll, they are just fatter because the volute has a divider down the middle. Also I got the 4" inlet port shrouded inlet on the compressor cover which only comes as a compact housing, making the turbine look even bigger.

 

The manifold runner volume does have some influence on boost response but I think it might limit flow if I ever want to put a big boy turbo on it (I won't be surprised if I buy I 2jz block and build it as soon as I get this thing on the road) we'll see. No quick spool valve, this will be a divided manifold.

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Snailed    3

I did one smaller patch today and then dressed all the welds on that side and metal finished them. It's pretty smooth but it would need more work if I was trying to make a show car. I might straighten it out a little bit after I media blast the whole car later. I threw on a coat of primer so it doesn't rust while I finish the rest of it. It's easy to wipe it off with thinner if I need to weld something, like the seam between the rail and the inner fender.

 

I'm thinking of using a progressive rate BMW steering rack...I'm doing lots of research on the suspension now.

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Snailed    3

I have been working on taking the manifolds and wiring off the engine and cleaning up parts of it as I go. I also got some aluminum 300zx or skyline calipers. The rears bolt on to the q45 spindles with a little trimming of the dust shield and the fronts may be fit to the Wilwood spindles or I may look at something a little smaller to help get the brake bias to the rear a tiny bit since I am guessing I'll have a 55%+ rear weight. I'm starting to think I won't make my weight goal...looking at lighter seats and maybe not making the tunnel quite as strong as planned.

 

Today I started fitting the engine and removed the tunnel. I'm raising the engine and moving it back a little, mostly so I can duct the radiator and intercooler exhaust through the top of the hood. This put the #1 spark plug slightly behind the front axle line. It looks like with the engine and pinion both at 0 degrees, I can get about 2 degrees total on the driveshaft split equally front and rear. I need to play with it a little more ans then start making front engine mount brackets. I'm thinking about using poly bushings for the engine mounts.

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Snailed    3

The engine and transmission mounts are up next. The factory engine mount brackets are a pretty excellent design but I don't want to mount the engine to the suspension subframe. I'm going to use 1.75" DOM tube and bushings attached to tabs on the frame rails. I believe mounting the bushings close to the frame rails should give me the least idle vibration with the most resistance to engine movement from Tq and shock from shifting for a given durometer.

 

I made the the plates that bolt to the block out of 1/4" mild steel with a 1.75 ID hole in the center. I tried to make them as light as I think I can get away with. There will be gussets to try and get the bending forces off the mounting plate somewhat.

 

I decided to start with rubber bushings because I think they will still be nice and stiff while absorbing a little more vibration than most poly bushings. I spent some time looking for OEM bushings that will press into standard DOM tubing sizes and I found the leaf spring bushings for a '91 Isuzu Rodeo fit a 1.75" x .120"  wall nicely. They are about $4 a pair for the higher grade Raybestos rubber ones and poly bushings are available if I change my mind later. The outer sleeves are just a piece of scrap DOM that I cut to length and cleaned up on the lathe. I figured out a cheap and easy way to make the inner sleeve too. 3/8" sch 40 pipe is the perfect OD to fit the bushing and the ID is good for a 12mm bolt. I bought a 12" galvanized pipe (needed 9") from the hardware store for $5.

 

I have engine position almost perfect but I want to refine it a little more before finishing the mounts so I made a couple holders for a $5 laser pointer. I bought 2 of the pointers but one of them was so out of alignment I couldn't use it. One holder just threads into the output shaft of the transmission and the pinion one is a magnet for the base. The pointers are carefully pressed in and then bent into alignment until the red dot does not move when the shaft is rotated. I saw this on some forum (here maybe?) and always wanted to try it.

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Snailed    3

I got the engine mount brackets welded up. The big tube is the same as the bushing sleeve, 1.75" x .120" DOM. The gussets are 14g. The pair ended up saving 2lbs over the stock aluminum bracket and rubber mount. No huge lightness "gain", but at least I'm not adding more than it had. The bushings feel pretty soft, but I don't think I can rock the engine even a 32nd of an inch at the valve cover. Can't wait to see how they work when it's together.

 

The tabs on the rails are made from 1/8" hot rolled steel. I think I will add some doubling plates around them and up onto the top out of 14g just to make sure they don't fatigue the 2.5" square tube. I think the steering shaft will just clear the tab on the drivers side, but I don't know the exact rack location (or even what rack) yet so that might get interesting.

 

I'm getting started on the framework for the tunnel too. Somehow the stock shift lever is just about perfect even though the engine is back a bit. I can reach 1-3-5 without pulling my shoulder off the seat, and 2-4-R don't jam my arm into the bolster. The knob will be close to the steering wheel too, which just makes it easier to drive.

 

The idea on the tunnel is to make it pretty strong in torsion without making it much heavier than the stock one. I already added a bunch of weight in the four lengths of 1x3 that run in the rockers and down the floor. In hindsight, I might have done that a bit differently so I could make the tunnel out of bigger chromoly tubing. As it is I'm just going to use 3/4" and 1/2" square tube and simplify it a bit. I will roughly follow a truss design and there will be four main tubes or chords and the middle will be filled with diagonal webs. It will be skinned with 22g steel. Beyond strength, design concerns include; room for plumbing/wiring up top, transmission cross member, heater box mounting, heat shielding for exhaust and room for seats. I'm open to suggestions on this project if you think I'm overlooking something or could improve my plans.

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Edited by Snailed

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Snailed    3

Here is the start of the tunnel. I mocked up the top panel out of 1/2" square tube with a .065" wall (6" wide by ~55" with no diagonals) and just that part had quite a bit more torsional rigidity than the entire stock tunnel I took out. The comparison was done using the step-on-it-and-twist-it testing protocol. It difference between the two was noticeable. I'll be welding up the whole thing on the bench so I hope to rig up a lbs/degree test to compare the two parts while divorced from the car.

 

You can also see roughly how the exhaust will be run. The bottom of the exhaust in the tunnel will be flush with the bottom of the car, which is the height of the rockers and the 1x3 that runs under the seats. It will be very easy to have it tucked up all the way back with the slightly raised drivetrain.

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Six_Shooter    13

The problem with comparing rigidity of your new framed trans tunnel and the stock trans tunnel when both are removed from the chassis, is that the original was really part of a much larger structure, including teh floor pans, firewall and rear support to tie everything together and re-enforce other areas. 

 

Looks good.

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