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cej2525

My V8 dream build.

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LS1 vs 5.3

 

Isn't the LS1 an iron block?

 

I'd go 5.3. Plenty of power for a light vehicle while staying light and still have the ability to bolt on more power anyways.

 

Both engines have plenty of aftermarket support. I just think the 5.3 would be better overall in the long run.

 

Not a Chevy kind of guy though.

The LS1 is an aluminum block 5.7. It shares all physical dimensions with the 5.3 other than accessories and intake. Yes the aluminum block does have its limitations but it is also 110lbs lighter. It will handle my HP target for sure. But if I decide to put a turbo in the bed later on in life I will want that iron block LM7. As of now I think the LS1 will go in and I will have the 5.3 as a back up or turbo build. I had a 86' Buick Grand National for a few years and have missed forced induction.

 

HCMBN4U.jpg

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Maybe i missed it but how will u get access to your distributor since svc is at the back and firewall will be in the way.

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The LS Series Gen III engines use a reluctor ring instead of a distributor. It has 8 independent coil packs mounted on the valve covers that fire off of a crank trigger/sensor.

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Depending on where you mount the motor, I don't think the extra weight will affect much.  But with that said, I'd go out of my way to put a large fuel tank (30 gal?)  as far back in the frame as possible to balance weight.  Our Bonneville truck likes 300 lbs of weight in the rear to help balance 50/50 with a stock engine.  

 

Yep the 5.3 will handle some boost!  Everyone who's anyone adds boost sooner or later... :devil:

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The engine bay is about 27" deep and the LS is about 27" without accessories. I am entertaining the idea of putting my radiator in the rear and running my accessories through the radiator support if it means I don't have to cut the firewall. But if I start cutting then it will be radiator an condenser up front. That way I have the bed space left for some sweet boost later on. So to answer the question of engine placement she will go where she fits! And you are absolutely right with the fuel tank. With the four link the rear space is wide open for the most I can fit. I have a fuel cell out of a 2001 Silverado that I am going to use. I believe its a 26gal tank and its ready for a Walbro 340. 

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Why not do a triangulated 4-link and skip the panhard bar?  I did this in my Willys pickup and it maintains center very well while still allowing full articulation.  Universal kits are relatively cheap at Summit.  I think that's what your Grand National had?  

 

I'd likely install the LS1 too, and have the 5.3 on a stand for a build, to be installed later once all the bugs are worked out.  My guess is that you're watching the dude from the Roadster Shop's 620 build with the rear turbos.  Rear radiators can be VERY problematic.  You'll need an expensive electric pump to move the extra volume of water front to rear and back - that's where most people fail.  If you plumb it in aluminum pipe, that could help shed heat as well.  

 

Once you start playing with Datsun sheetmetal, you'll realize that its insanely malleable.  Its a great way to learn the new skills!

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I know that there is a big debate out there on panhard vs triangulated. I guess my main reason is that I have FAR more experience with a panhard set up. I have also been thinking about the Watts link. Some folks say its an eye sore but I like it.

 

Yes, Mike O'Brien is a master at the game. I wanted to do this swap far before his build but I admit he put the fire back in my drive with his project. Rear radiator set ups are pretty common in the rock crawling world that I was engulfed in for so long. Sue it's not as easy as a front mount but I want to keep my options open. Yes the front mount is optimal because I still need to move engine bay heat. For that reason alone I'm still not convinced of the rear mount. 

 

On a turbo set up the bed mount makes sense for a daily just to keep the air filter clean. But when it all comes down to it the only way to find out is to get the cab on and start playing with it all. And that was my thoughts exactly for the 5.3. Sit on it and scoop up some good deals on internals and go big. I have a LS6 intake and truck coils that I will be using up front. And I still can't decide if I will do a cam swap before installation or not.

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When you need more power go big.   :devil:

 

The Watts link is more designed for track than street, in my understanding.  Limited suspension travel, but very precise.  Beebani's system looks pretty good (Ebay and Instagram), but I don't see that it has any adjustability, which you NEED with any ride height change.  You can't just throw your roll center underground and forget about it.  I've done panhards and more often than not they inflate existing bump steer problems.  

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Looks good.   Who bent your frame rails?

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Throttle induced oversteer. That's a term you should familiarize yourself with.

 

Deciding between the three different suggested suspensions really means you need to sit and think about how you want the truck to handle. If you are going to have some good horsepower than I would think it's important to keep the back end in line.

 

I'm going to list the designs from worst to best (speaking in terms of controllable handling characteristics).

  • Most guys use the basic hotrod parallel 4 link because it's easy, but they leave a lot to be desired.
  • Triangulated 4 link (full or semi) - hard to control roll center on this setup. It's very dynamic. Since roll center is crucial to being able to plant the throttle, this setup should be left to the experts..
  • It's really no more work to build a three link with panhard. The most important part of this equation is getting the height of the panhard right. The length and separation of the upper and lower control arms is important too, but often these are delegated by the space you have to work with. The upper link should be 2/3 the length of the lowers, so maybe start there.
  • Watts linkage is the best for controlling roll center, but packaging can be very difficult. It's important to note that the center bolt of a watts linkage is the roll center, so place it where you know you want it. If you can't determine where you want it and want to make it adjustable, the job of packaging just became more difficult.

Here's a three link I built in a Nova a bunch of years ago. This guys came to me and told me he wanted comfort and high horsepower cornering, so a lot of thought went into the design. You can see how tight it was getting it all to fit. The top link was short, but adjustable. We also used large urethane bushings on the top link to get better bite under acceleration, but also help eliminate wheel hop under braking. Kind of like a circle track pinion snubber.

 

Here are a couple pics.

 

IMG_3824%20Small_zps8ybxkcio.jpg

 

IMG_3822%20Small_zpsow8kqeky.jpg

 

Nova_Floor_Small_026_zpsou3gn72f.jpg

 

Nova_Floor_Small_023_zpsfq5s0prk.jpg

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 Yes, the drop spindles dramatically change tie rod angles, so smart to leave the rack until last.

The reason for drop spindles is that well designed ones don't change suspension and steering geometry while lowering the ride height

 

Love this build so far

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Looks good.   Who bent your frame rails?

I bought them from Checkered Racing already bent. real nice pieces! 

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Throttle induced oversteer. That's a term you should familiarize yourself with.

 

Deciding between the three different suggested suspensions really means you need to sit and think about how you want the truck to handle. If you are going to have some good horsepower than I would think it's important to keep the back end in line.

 

I'm going to list the designs from worst to best (speaking in terms of controllable handling characteristics).

  • Most guys use the basic hotrod parallel 4 link because it's easy, but they leave a lot to be desired.
  • Triangulated 4 link (full or semi) - hard to control roll center on this setup. It's very dynamic. Since roll center is crucial to being able to plant the throttle, this setup should be left to the experts..
  • It's really no more work to build a three link with panhard. The most important part of this equation is getting the height of the panhard right. The length and separation of the upper and lower control arms is important too, but often these are delegated by the space you have to work with. The upper link should be 2/3 the length of the lowers, so maybe start there.
  • Watts linkage is the best for controlling roll center, but packaging can be very difficult. It's important to note that the center bolt of a watts linkage is the roll center, so place it where you know you want it. If you can't determine where you want it and want to make it adjustable, the job of packaging just became more difficult.

Here's a three link I built in a Nova a bunch of years ago. This guys came to me and told me he wanted comfort and high horsepower cornering, so a lot of thought went into the design. You can see how tight it was getting it all to fit. The top link was short, but adjustable. We also used large urethane bushings on the top link to get better bite under acceleration, but also help eliminate wheel hop under braking. Kind of like a circle track pinion snubber.

 

Here are a couple pics.

 

IMG_3824%20Small_zps8ybxkcio.jpg

 

IMG_3822%20Small_zpsow8kqeky.jpg

 

Nova_Floor_Small_026_zpsou3gn72f.jpg

 

Nova_Floor_Small_023_zpsfq5s0prk.jpg

 

Man that is some in depth geometry for sure. I know the old 4 link may not be the best. I've seen some that would hook on a gravel road and others I wouldn't idle down the driveway in. Like I said it's something I'm comfortable with and I do love the simplicity. Is there better out there , absolutely. But I don't want to get over my head on something I don't understand. Sure it may not corner like a rockstar or have steering like a Cadillac but it will take me to Lowe's with a smile on my face.

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Nice work on the Nova!!!  Do you leave one jamb nut loose on the 3-link to allow the axle to articulate, or are you applying that load on the bushings and asking for forgiveness later?  A heim on one end would absorb the twist while the other end in poly or urethane would compress under load (maybe not enough?)    Single exhaust?  

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Man that is some in depth geometry for sure. I know the old 4 link may not be the best. I've seen some that would hook on a gravel road and others I wouldn't idle down the driveway in. Like I said it's something I'm comfortable with and I do love the simplicity. Is there better out there , absolutely. But I don't want to get over my head on something I don't understand. Sure it may not corner like a rockstar or have steering like a Cadillac but it will take me to Lowe's with a smile on my face.

So you have your heart set on a parallel 4 link? It sounded like you were considering a 3 link also. Search Google for 3 link calculator or try this page http://www.patooyee.com/calculators/calculators.htm (there's a 3 link tab below the second pic) and play around with numbers. It's not that hard to come up with something that would work. If you have any questions, I'd be glad to help with some pointers.

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Nice work on the Nova!!!  Do you leave one jamb nut loose on the 3-link to allow the axle to articulate, or are you applying that load on the bushings and asking for forgiveness later?  A heim on one end would absorb the twist while the other end in poly or urethane would compress under load (maybe not enough?)    Single exhaust?  

Thanks. That was about 7 years ago and I've learned a lot since. Jam nuts are supposed to be left loose...right? Better articulation and all...

 

I only use heims on offroad vehicles or on a panhard bar. Never on a street driven car's control arms. Just the way I do it. I hate the clunk they get over time.

 

Yes, single exhaust. custom full length headers with merge collectors and cone reducers to 2.5" y-pipe. Then a 2.5" to 3.5" merge collector to a 3.5" muffler. 3.5" reduced to 3" from the muffler back. I am fortunate to have SPD in my area and whenever I need help designing an exhaust, they are happy to help (as long as I buy the tubing from them). I think single exhausts sound so much better on a V8, especially when they're tuned properly. The motor in this car is a carbureted LS3.

 

Sorry for the thread jack. I just wanted to give you some ideas for the rear suspension.

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I see no thread jack here sir!

 

I am always open to suggestions. If you're not open to suggestion or looking for feedback then why post on a forum. Will definitely look in to it. Never hurts to learn something new. 

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Ok, cool.

 

One thing I forgot to mention: you don't need to have the top (third) link directly in the middle of the axle. You can shoot it off to one side to give you more diff to floor clearance, like I did here -

 

Les_9_Small_016_zpsbynnb6ln.jpg

 

It doesn't look like it since this axle is offset, but with a centered diff, this top link would be about 8" off centerline. Also, you don't need as much distance between the top link and lower link (at the axle) as this has, since you will run smaller tire. Use the 25% rule where the distance between the bolt going through to top link joint and the bolt going through the lower link joint (at axle) is 25% of the diameter of the tire. ie a 40" tire need 10" vertical separation between joint centers.

 

Les_8B_Small_024_zps1rsbd14q.jpg

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Ok, cool.

 

One thing I forgot to mention: you don't need to have the top (third) link directly in the middle of the axle. You can shoot it off to one side to give you more diff to floor clearance, like I did here -

 

 

 

It doesn't look like it since this axle is offset, but with a centered diff, this top link would be about 8" off centerline. Also, you don't need as much distance between the top link and lower link (at the axle) as this has, since you will run smaller tire. Use the 25% rule where the distance between the bolt going through to top link joint and the bolt going through the lower link joint (at axle) is 25% of the diameter of the tire. ie a 40" tire need 10" vertical separation between joint centers.

 

 

Love learning this stuff

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Thanks for taking the time to bring all of this to my attention. I will probably end up doing something temporary until I get the body and engine fitted up. That way everything will be in place including ride height so I can lay it out properly.

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There is a lot of great information and knowledge in the depths of Ratsun.  It is excellent that we have the master builders on here that keep us try it test it and re do it until we get it correct guys and girls headed in a direction of some success!  LOL

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I have already got a lot of food for thought since the beginning of this post. I hope the comments keep coming so my mind won't sit idle!

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Looks like you got a Yeti full of good ideas!

 

cool stuff!

.

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Looks like you got a Yeti full of good ideas!

 

cool stuff!

.

I keep plenty of Blue Moon on hand. It helps to get my imagination going!

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