What would you upgrade on my car?

[fusion]

Car is a 1976 280z.  100% street car.  In the middle of building it.  Current drivetrain is a single turbo 5.3, t56 magnum, Ford super 8.8 rear diff with 2015 mustang rear disc brakes.  6 point roll bar. BC coilovers on all 4 corners.   All poly bushings.

I won't be tracking the car but it should have a lot of power and I do want it to be stable at speed and be able to put the power to the pavement.

 

Trying to figure out the best things to upgrade suspension/brakes wise.  Don't want to upgrade just for the sake of upgrading, but where it really makes a difference for street driving.  This is my first Datsun so I'm not that familiar with the best upgrades.

 

Currently stock:

Moustache bar

Rear drop mounts/dogbone

Front and rear control arms

Front and rear sway bars

Front brakes 

Front tension rods

Steering rack

 

Tentative plans:

Upgrade stock front brakes with Toyota calipers and solid rotors

Silvermine electric power steering

 

Would love input from people who have valuable insight.

 

Thanks

 

 

Edited October 26, 2021 by fusion

[rturbo 930]

2015 Mustang rear brakes that are probably 13" and Toyota brakes up front I don't think is going to be a good combo given that the front brakes do most of the braking. So I'd upgrade those to something more appropriate. 

 

Nothing really sticks out to me as a major problem except maybe sway bars, I would probably just upgrade as needed. Sounds like you've already done a ton of upgrades already if you've got a Ford 8.8 diff and a turbo LS. Since it's just a street car I don't know how quickly you'll find the limit of the components you have, and I don't know your driving style, if you're just hammering it on straights, or trying to push it in corners. 

 

Another thing that just occurred to me, which I don't see any mention of, is the structure of your car. Do you have subframe connectors or any other chassis strengthening? If not, I would do subframe connectors at a minimum. 

Edited October 26, 2021 by rturbo 930

[fusion]

Ah, yes, I forget to mention that I have subframe connectors and also added support bars to the inner front fender horns as well

[jhm]

I agree with @rturbo 930.....if you plan to upgrade the front brakes, I'd go with something other than the Toyota calipers.  Those things weigh a ton and it's all unsprung weight.  There are numerous options/kits out there that incorporate aluminum calipers and vented rotors.  Also, if you ARE upgrading the front brakes, why would you want to keep solid front rotors?  Those are actually the biggest achilles heel of the OEM system, as they are prone to overheating when subjected to sustained, intensive use.  Since you've already swapped the rears for discs, I'm assuming that you've also gone with a bigger MC?  If not, that should be on your near-term list.

 

I know your question is focused on brakes and suspension, but have you upgraded your seats?  That alone can make a huge difference in driving pleasure and comfort.  Lots of good choices from Recaro, Sparco, etc....and there's a couple good threads here on seat swaps.

 

Your combo sounds super nice -- I hope you're enjoying it!!

[Michael]

Not exactly qualified to offer "valuable insight" here, but what about overall tuning (engine and engine management, wheel alignment, ride-height, brake bias,...)?  The ingredients-list is already breathtakingly impressive, but how well does everything work together?

[fusion]

Thanks for the comments.  I am in the process of building it now.  The drivetrain is done along with most of the body work.  I got the car as a rolling shell and have never driven it.  I just don't have the experience to know what stock parts can really benefit from upgrading.  For example, I don't know if the stock moustache bar or stock front control arms are worth upgrading.

 

Points taken on the front brakes.  I'll definitely look to get something better.  I am running 15" wheels so that is a consideration.    I don't have a master cylinder picked out yet.   I was looking at the Toyota Tacoma upgrade that some others have done.

 

I already need to buy a new rear sway bar since my stock one that goes in front of the diff won't fit with the super 8.8.  I'll probably get the ST rear kit.

 

As far as seats, I will be running 2000 Viper seats.  They fit and look great after some minor floor pan surgery.

 

I will definitely be doing all the chassis and engine tuning once I get the car up and running.

 

Thanks

[joyce_mor]

If you're still doing an upgrade, I recommend that you take advantage of the Black Friday deals. A new set of wheels and tires make a difference and it will add more value to your classic car. 

Edited November 26, 2021 by joyce_mor

[AydinZ71]

At the risk of not reading your thread in detail (thanks ADHD), I do want to suggest chassis stiffening. I have driven a friends race car, and then jumped in my 71’ L28et street car. HUGE difference. 

 

You didn’t mention your spring rates, but I will assume they are somewhere between a race car and OEM. High torque and stiff springs is a combination that may put too much stress on the chassis, without stiffening. 
 

I see you have a 6-point roll bar. That’s a wonderful launching point to complete the rest of the cars stiffening. If you don’t mind (your chassis is not rare, yet), welding a permanent support between your rear strut towers, with diagonal stiffeners (will look like a “K” turned 90 degrees clockwise. This adds much more rigidity than just a fancy strut bar. Those are design yo keep the top of the towers separated equally, but allows for independent movement up-and-down. I assume your roll bar terminates on your rear towers already. That’s a must. 
 

the roll bar does not do much for the front though. Consider adding tube steel from the front strut towers to your firewall at an angle point towards the centerline of the car. Then pick-up from the cab side of the car, and add a tube to your roll cage. Many pictures online of race car S30’s as an example.

you can add a vertical stiffener on your strut towers down to your unibody frame rail. Just remember, the high stress applied to your chassis is at all four towers, your engine mounts, and your diff mount. Therefore, no need to stiffen in front of your front towers, or behind your rears. Although stiffening outside of this footprint does still help, you are adding weight that is “cantilevered”. Not supported by 2-sides, but like holding a grocery bag with your arm outstretched. 

 

stiffening the chassis will add steering and acceleration response. With engine/turbo/trans/8.8 (unless you have the AL housing from an auto) your car is going to be at least +150lbs heavier than OEM. More weight also contributes to more chassis stress, along with the stiff suspension and extra torque. 

[fusion]

Thanks for the comments.  I do have new wheels/tires for the car.  As far as chassis stiffening, I do have the cage tied into the rear shock towers.  I also have new box tubing frame rails, subframe connectors to the rear subframe, gussets to tie the rear subframe together better, tubing from the back of the tension control mounts to the firewall and tubing from the top of the fender horns back to the firewall.

 

Unfortunately I don't have any room inside the engine compartment to add any other tubing to the strut towers.  But this isn't a race car so I feel ok about it.  I might add a removable strut tower brace.

 

I did just pick up the T3 300mm front brakes today with the Black Friday deal, so I think the brakes should be good.

 

 

 

 

 

[AydinZ71]

Looking great!! 
 

here are some pics of mine to give you some ideas. The idea being, there are means of stiffening the towers that don’t need to introduce more bulk to the engine compartment. Looks like you are on the right track! Good luck!

 

these are old pics so the chassis Has progressed since then, but they capture the individual tube supports. 

 

 

[fusion]

Nice work.  Any reason why you made the tube from the tension rod area to the firewall curved instead of straight?

[AydinZ71]

Ah! This was installed by the previous owner, but I kept it. Picture yourself in the drivers seat. There is a roll bar between your seat and the inner rocker panel (SCCA roll-cage spec). Now picture that roll bar continuing through the drivers toe plate (firewall), then bending towards the tie-rod attachment point. All this to say, it’s a single continuous section of roll bar that was “bent” inward, vs. 2-pieces. 

 

the roll bar is MUCH thicker than the tubes I used for chassis reinforcement. Nearly 1/8” thick wall, vs. 18-gauge for the stiffening tubes. 
 

there is a ton of force on that tie-rod attachment point on a race car (slicks/grip + hard braking), so that bar helps counter the force and reduce body flex and poor response.

Edited December 1, 2021 by AydinZ71