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jpndave

240Z Pro-Touring Build

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jpndave    1

I'm all ears, 3.31 wouldn't be too bad with a CD009 and it's 3.79 first gear

I don't think you would want much lower than that or you'll just spin. I'm concerned I might be too low with the 3.73 rear and 2.97 first. You would end up with this (not sure what your power band would be like, best shift point).

post-31627-0-51279800-1464141021_thumb.png

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jpndave    1

Happy to oblige Sirpent. ;) Just wish it was more often/more progress faster. Labor of love though. I need to unload a few other projects so I can get my body parts coming from John Washington.

 

Snagged that 2nd rear so looks like we're building two sets of brackets!

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Looks like a very nice project. I really like the Tremec, both 5th and 6th are overdrive compared to most 6 speeds which 5th is not OD. So they have an engine with a narrow powerband and you are rowing more gears just to end up with the same OD as a 5 speed. With this much torque you don't need close gears and you might as well have double overdrive. I would go a little lower in the rear, sure you have a hookup problem but it would be more boot in the back. And with double OD a true highway car, you're going to be longing for an Autobahn to make use of it. What's your theoretical top speed?

 

There's some (unresolved?) controversy about using 4130 for a cage, something about welds being brittle. And the purpose of going with Chro-mo is to reduce weight, and since 1.5" x .096" DOM is up to racing specs for this weight of car, you could go the next size thinner in Chro-mo.

 

The a-arms conversion takes forever because this chassis is not set up for it. The GTRZ project I'm doing has a Skyline chassis clip in the front because it would just be too extensive to build all the mounts necessary.

 

The stock Z rack is a really nice piece, the earlier years had an aluminum gear case. If you do change it make sure what you're putting in is actually lighter and at least as quick of a ratio. There may be something out there better but I haven't found it.

 

I would put the chassis on the rotisserie from the start. You really have to be missing a lot of sheet metal before it moves from it's own weight. The two Z's I've recently done were both extensively rusted, complete rails, most of the pans and firewall parts. They didn't move at all with everything cut out at once. Make some measurements just to monitor things but you shouldn't have a problem.

 

Kudos on going the road less traveled on the engine, it's going to be different and it's going to be a screamer.

Edited by Chris Duncan

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jpndave    1

Thanks for the reply Chris.

 

I don't dare go any lower in the rear and it is already starting to push economy at cruise. I don't think gearing will be a limitation on acceleration, should be traction limited even with sticky 295 tires. Top speed will be power limited with a teoetical of . 200mph would be at hp peak in 5th. The I am certain will be pushing it. Here we have several "legal" choices to use that speed. Salt flats are a few hours away. Road course at Miller Motorsportz Park about 1-1/2 hrs and the run outside Vegas as well as their track about 6hrs. I wouldn't mind just seeing what it will do at least once. Got to get it built first which is proving to be a very slow process.

 

4130 is stronger but definatly needs to be welded properly. I already have the tubing from an abandoned project. I'm also planning on 4130 in the supports, floors, suspension and scattershield for the tunnel. Trying to save weight wherever remotely practical while increasing strength. I have Miller 200DX TIG and 350P MIG to weld with. Proper prep, back purging and post weld normalizing will be in order.

 

I know the A-arms are adding some work but the end result is much superior and I'll regret it if I don't being as far down as I am on metal replacement now is the time. I'll take a look at your project for ideas there.

 

Stock rack is aluminum but I have two concerns with it: Width, It will need to match the suspension pickup points for bumpsteer, and Strength. We'll see how it matches up.

 

I really appreciate the comments on getting it on a rack. Been worried about that. One of the front rails is buckled and pushed slightly back. I think I need to get those sorted out first then up on the rotisserie. Not sure how to make a rotisserie work without the rails there unless I weld in a temporary support in the engine bay which might be a good idea actually.

 

I have seriously gone back and forth on the engine. I am intimately familiar with the LS family. That route would be cheaper and easier, no contest. Lighter than a Coyote (LS is ~430, Coyote ~444, heavier than Voodoo, no specific #s I have found overall but the crank alone more than makes up the difference). However, I love having a high revving exotic sounding engine in that car. The LS can be made to rev at an exponentially higher cost the higher you go. But, by camming it to do that you lose the smooth bottom end so at highway cruise it would be loping which doesn't work even using their VVT. My Jeep is right at the cam limit for keeping the cruise and it's more than 1000rpm off on the top end. There is no way to get an exotic BRAPP sound out of it, destinctive and cool? Yes! But not the same spine tingling sound. It would sound just like my 6.8 in the Jeep. Also, power delivery is much better to avoid wheelspin. Not quite as strong on the bottom but more on top, very progressive build of power and tons from about 4k to the 7200 peak and on up over 8200. Coyote will just be a stopgap if necessary.

 

I'm rambling, thanks again for your comments. I'll look into that suspension and rotisserie info.

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Yeah, if you're going with custom suspension a custom sized rack may be in order. I am looking for another rack for the GTRZ because the Skyline is RHD and rear steer, as opposed to the Z rack which is front steer. Haven't found anything yet that is semi-affordable and has a quick ratio like the Z rack. Don't know if I want to pay $1000 for a rack when a Z rack goes for around $100. I'm going to maintain easy steering by taking out caster. If I do need power steering it's going to be electric at the column. Just way less clutter that way.

 

I've scratch built three twin a-arm suspensions and it takes longer than you think, especially if you want to really fine tune the handling. It can get complex and becomes sort of experimental. So you're not sure about the end result until you drive it.  Went a different route on the GTRZ just to save some time. Essentially bolting up the entire Skyline sub frame in the rear and the Skyline body clip and sub frame in the front. And if wanted later on can either duplicate the stock arms with tubing or get aftermarket tubing arms off the shelf. One thing that was nice about this was I lowered the car 1" just by lowering all the mount points on the chassis. As opposed to lowering by shortening the springs/struts which compromises geometry.

 

I bolted up to the bumper mounts when using the rotisserie.

 

Miller is a really nice track, wish it wasn't so far from here. And wondering about it's future since it was sold?

Edited by Chris Duncan

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jpndave    1

You should be able to pick up a Sweet or similar rack off of eBay for a decent price. Just will take some patience to get the right ratio and width. That's the direction I'll go. I haven't nailed down all the geometries yet. Debating on hubs, etc. I'll probably use the late Mustang parts just because that will make the rear half-shafts easier and cheaper as well as a really common bolt pattern, brake availability, etc.

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jpndave    1

Not yet. I'm sure it will be hard to find and expensive. I am searching now. Progress has bee slow due to building a new house/shop. I'll put a Coyote in there to get by until I can source the Voodoo if I have to. Rear pattern is the same. I'm sure I can make money on a Coyote long term. I already have some of the necessary parts for the upgrade on a F150 based engine. They can be had really cheap. Rods, cams, a few covers and maybe some port work and your over what a Mustang would be. HPTuners (which I already have along with Ford credits) will flash the ECM on either.

Edited by jpndave

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jpndave    1

Only small steps lately as I'm building a new house with a little nicer garage/shop attached. Has consumed most Z time. 1969honda  and I have been working on the rear a bit. Have the aluminum carrier and he has a complete sub assembly we're going to pull at least the pickup points from. Looking at possibly using hubs and brakes as well. We'll see how it goes.

 

Grabbed a fiberglass spoiler like my old urethane to build on, rockers and some extra new front lenses. Also, parts for a rotisserie.

 

As soon as this house is out of the way and I can focus on more important things I'd really like to get the bodywork package here and the chassis up on the rotisserie.

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1969honda    1

Good to hear one of us is at least accumulating some parts! My life seems to be consumed by work right now as well, found out I'll be gone for a few weekends this month and most of the next month as well

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jpndave    1

Thanks for the input Ryan but that would kind of defeat the point of the build. It may get a Coyote temporarily. I have a set of rods for one already so I could use a truck based engine even earlier years and might even make a bit of $ when it comes out to go towards the Voodoo. Long term, I'd just do an LS if that were the goal. I'm intimately familiar with the platform, have lots of parts, etc. But, I want the sound, high RPM revs and the way the power delivers from that flat plane crank. 500hp to the wheels will be great and the car might actually start out without completely being out of control. Will it cost quite a bit more? Pretty sure that will be the case. This isn't a budget build.

 

Sadly not a very fast one either. Hopefully some updates will come in the near future. We're working on the 8.8 from the new mustangs and are getting closer on that project. Just moved it over to my new shop/garage for storage while I finish up the house and get everything else moved over. Thought I had a rotisserie all sorted but 1969honda came up with a better idea so I may go that route instead. Collecting a few pieces here and there. Just no time to dive in until the house is done.

post-31627-0-88000900-1503367080_thumb.jpg

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tube80z    17

My advice, from screwing up this a number of times, is to get the engine and tranny last.  You never know how long it will take to complete these projects and what looked awesome now may be a lot less awesome in years to come.  Not to mention potentially cheaper.

Cary

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