ANOTHER Datsun Z/LS3/T56 Swap Thread

[lifeprojectZ]

Did you happen to use a sound deadening headliner, or is it sprayed metal?   I noticed a huge difference in inside noise of my '81 Buick (full of original carpeting, sound deadening) with 350 crate engine, 3" dual exhaust when I got the bright idea to rip out the sagging headliner and paint the metal.   At that time I enjoyed the sound (25 years ago) but today I wouldn't.   I appreciate your comments on the noise.  Will go extra heavy on the sound deadening!

 

The AME sales guy talked me out of a 3" dual exhaust for my Z for the reason of being too noisy.   I had never thought about the exhaust size making a difference in noise transmission to the interior, but he has seen/ heard a lot more than I have.  My biggest obstacle to a 2.5" dual exhaust is mental and too much past reading about exhaust sizing needed to extract every last HP from the engine.  I doubt I'll be spending much time above 6000RPM with the LS376/480, and the lower RPM torque will probably be a closer friend.

 

Originality?  That is extremely important to me.  In fact I bought factory original replacement body vent emblems, and plan on installing them........

[JMortensen]

I did the 2.66 Woodward rack. I don't drive it on the street, but I would. I don't think it's too sensitive, although you might be in trouble if you were leaning down to get something off the floor and weren't paying attention. Much nicer in slaloms.

I also did the Holley 302-2 and and Improved Racing baffles and a 3qt Accusump. I have a 30 lb low oil pressure light, haven't seen it come on when autoxing on 14" wide slicks.

More info on my swap here: 

 

[Ironhead]

I used Lizard Skin sound deadener on the inside of the roof, but again, all it really does is get rid of the tin-can ringing effect.  It doesn't deaden noise much beyond that.

 

It's funny, I am using dual 3" exhaust and I don't consider the exhaust on the car to be particularly loud at all.  The "noise" in the car is mostly coming from other places...suspension movement, road noise, and engine mechanical noise primarily.  My exhaust does include a resonator and two large mufflers though.   I wanted the dual 3" just in case down the road I decide to be an even bigger idiot and seek more engine power, the exhaust won't be a limiting factor.

 

Regarding the 2.66 rack, that would be way too fast for my tastes, but then again I don't autox.  If I did I would probably see it differently.

Edited March 3, 2022 by Ironhead

[lifeprojectZ]

On 3/3/2022 at 4:06 PM, JMortensen said:

I did the 2.66 Woodward rack. I don't drive it on the street, but I would. I don't think it's too sensitive, although you might be in trouble if you were leaning down to get something off the floor and weren't paying attention. Much nicer in slaloms.

I also did the Holley 302-2 and and Improved Racing baffles and a 3qt Accusump. I have a 30 lb low oil pressure light, haven't seen it come on when autoxing on 14" wide slicks.

More info on my swap here: 

 

Thank you!  That is a wealth of information.   If you don't mind, how much ground clearance do you run with the Holley 302-2 pan?   I am wondering where my LS will end up in the AME chassis.   I want it as low as possible of course but I don't think I would want much less than 4" ground clearance with the pan.   Won't know for sure until I get it in there and start playing around.   

 

 

[JMortensen]

I have the front crossmember 2.5 inches off the ground and the pan is slightly higher. I made my mounts so if you're using off the shelf stuff YMMV. My goal is to eventually run a paneled bottom. I had to raise the drivetrain because the T56 was hanging down below the frame rails (Bad Dog SFCs). 280 rails are taller so there is a little wiggle room there. 

[tube80z]

On 3/3/2022 at 4:19 AM, lifeprojectZ said:

I think I bungled/ swapped the words tandem and dual in my question about the brakes, but your answer is completely understandable!   I am going with Wilwood SL6 calipers on front and still unknown rears, and am pursuing an option to keep a small, maybe the OE, booster, as I am kind of addicted to low effort brakes and mine will be mostly a street car.

 

I've seen some Porsche cup cars that use a booster and a dual master bracket that bolts to it.  John Coffey used to sell a setup like this years ago but I seem to recall that he deleted the booster.  The downside to this is it takes up additional space in the engine bay.

 

For my street car I'm looking at using the Bosch i-booster, which uses an electric motor rather a vacuum assisted booster.  Here's a video from Bosch, 

 

These are used on Teslas, which is where I first saw them.  The good news is they are on many new cars and fairly cheap on ebay.  And don't worry about sensors as this will run in limp home mode and act like normal vacuum assisted brakes.  The good news is these come on a lot of cars that have cheaper parts then a Tesla (Honda, Toyota, etc.)  In this video jump to it shows the wiring setup and some cheaper alternatives, 

 

 

Hope this helps,

Cary

[lifeprojectZ]

That looks great.  Maybe someone will develop a retrofit kit with adjustable assist.   Maybe not due to liability.   Looks like it takes up about as much space forward of the firewall as a vacuum booster though.   

[lifeprojectZ]

On 3/3/2022 at 5:14 PM, Ironhead said:

I wanted the dual 3" just in case down the road I decide to be an even bigger idiot and seek more engine power, the exhaust won't be a limiting factor.

 

Sorry if I missed this somewhere in the preceding 28 pages, but I don't recall your assessment of the 525HP other than your initial impression.   Now that you have driven the car a bit, do you think you would ever want or could use more HP?   Is first gear even usable with the rear diff ratio you choose (above 4:1 right?)

 

Also, I saw your dual master cylinders and the balance bar set-up, but what size rotors front / rear and caliper piston area do you have front vs. rear?     Considering all this, what do you think your current braking torque balance is front / rear after your tuning and are you happy with it?   Did you you ever weigh your car to see what the weight distribution came out to be?    These are the things that keep me up at night...    

 

[Ironhead]

I think the gearing/final drive is perfect for a track oriented car, not so much for street driving.  In 6th gear at 75 MPH it is turning around 2700 RPM.  I am only getting around 10 MPG street driving.

 

The HP was alarming when I first drove the car, bit I have gotten used to it.  The car puts power to the ground very well, amazingly well, actually.  I can certainly break the tires loose, but only if I do it deliberately.  Rear "R" compound 315 wide tires definitely do their job.  I have no desire yet for more power, but I think the car could handle it fine.

 

I have not weighed or corner balanced it.  It could definitely be pretty heavy for a Z.  I built it prioritizing strength/safety over light weight.  

 

Once I got the brakes dialed in, I think they are perfect.  Except for the squealing.  That is horrendous.  Driving through my neighborhood I stop with the handbrake, just so my neighbors don't come after me with torches/pitchforks.  For some reason just using the rear brakes kills the squeal.

[calZ]

How's the car been? This is still one of my favorite threads. 

[Ironhead]

5 hours ago, calZ said:

How's the car been? This is still one of my favorite threads. 

Thanks much!

 

It's all good.  Far more reliable than I ever expected such a concoction to be.  Thoroughly enjoying it.  No complaints at all, except I don't drive it much in the summer here because the interior gets pretty warm.

Edited August 18, 2022 by Ironhead

[calZ]

Time to add AC? 

[Ironhead]

5 hours ago, calZ said:

Time to add AC? 

Naw.  Not that kind of car.  I'm fine with it as is.

[Woodruffhallz]

Awesome build! And highly informative. Do you have an IG or similar so we can see more?
 

From your exp, were the stitch welds worth it? I want to do a 1JZ swap aiming for 450 hp. I’m adding F and R strut braces with the AE F/R subframe mounts. Frame rails are kind of a must, but drilling out all of those pinch welds gives me nightmares.  Also, the engineer in me knows I need some sort of rear to front

— top to bottom load path, but I’m also 6’3” and I want to safely drive the car on the road w/o a helmet. So l’m thinking a harness bar that bolts into the UPR/LWR seat belt locations  would be better than nothing. 

 

pick of my build attached. Just painted this. 

 

 

[Ironhead]

I didn't post anything else anywhere about the build.

 

It's difficult to quantify the effects of the stitch welds, partly because I hardly drove the car at all before tearing it apart.  I can say now that the body shell is extremely solid, and does not feel like a 50 year old car, but that's subjective of course.

 

The bottom line is that I installed more than three times the HP and torque the car was designed to handle, and I think it just makes sense to strengthen up the structure in any way you can.  So I did the stitch welds in addition to beefier frame rails and an eight point cage.  Of all of it, I'm pretty sure the cage would make by far the most difference.

 

I drive it on the road without a helmet, but I do use a (snugged tightly) six point harness.  I also have FIA roll bar padding everywhere that my head could possibly contact.  Obviously the car is nowhere near as safe as any modern car, but I'm comfortable with the risk level.  It's sort of like choosing to ride a motorcycle.  You accept the risk, stop thinking about it, and enjoy what you're doing.

[tube80z]

16 hours ago, Ironhead said:

It's difficult to quantify the effects of the stitch welds, partly because I hardly drove the car at all before tearing it apart.  I can say now that the body shell is extremely solid, and does not feel like a 50 year old car, but that's subjective of course.

 

Back in the early 90s, I had the fortune to chat with an engineer from a IMSA World Challenge team.  I had noticed they had done a ton of stitch welding to the shells and was curious if this was done for increasing torsional strength.  He told me on the new shells they used saw no improvement from this, and they did so they could easily repair crash damage.  He did say that for an older car it would most likely show improvements, but you'd need to test before and after to get any idea of the improvement, but he didn't expect it would be all that much.

 

One easy improvement can be done by gluing in the windshield rather than using the stock style rubber gasket.  I helped a friend do this on a 280 used for Chumpcar racing.  With the stock seal the chassis would understeer and after it oversteered.   From a feeling change it was like adding a triangulated front strut bar.

 

@Ironhead I know you've accepted the risk of driving the car with the roll cage, but I did want to point out that FIA padding is meant to be used with a helmet, not your noggin.

[Ironhead]

Quote

 I know you've accepted the risk of driving the car with the roll cage, but I did want to point out that FIA padding is meant to be used with a helmet, not your noggin.

Oh yeah, I know.  But even without a helmet, I would rather bang my head on FIA padding than on a steel tube.