AydinZ71

sorry friend. 250hp on an NA L24E will cost you $10-15k and will not be enjoyable to drive on the street. 300 is impossible NA without NOS. Adapting a turbo will cost you the same on an L24 as it will on an L28. If you really want those power numbers, consider a modern engine swap, an L28et from a 280zx with bolt-on mods and tuning $4000, or throw $5000 at an NA 280z and turbo it.

@clarkspeed yep i think that's what I'm going to do. The passenger side inspection lid cubie is currently occupied by the engine vent and radiator overflow reservoirs, so i just need to relocate them.

In case you would consider FRP over steel, ZTrix Makes them. They can also build them to accept window regulators, doors cards, etc. I just ordered an FRP hatch from them for the race car.

I have yet to meet a shitty Dutch performance part vendor. Koni is Dutch as well. If they had a bigger country, maybe they would make cars too 🤷🏽‍♂️😂

right!? I think the previous owner just wanted to meet the regulation for driver protection and didn’t give much thought to rigidity. @gnosez gave me a lot to think about on tie-rod compression stress on heavy braking with slicks. Il use this point to brace the tie rod box vertically, and il add another reinforcement lower in the car to brace the horizontal flex.

@MetalMagoo here is my current disaster. I am going to build a reinforced L-bracket and weld it to the end of the roll cage. Then I have a platform to run additional steel tube reinforcement. I didn’t like how it just terminated at the firewall, without taking further advantage of the cage. IMG_5455.MOV

hmmm, good consideration! It is an AGM battery, and designed to be mounted flat or upright. The race car has no windows at the moment so not too worried about venting. Il do some more research though! Thanks for giving me something to think about

@JMortensen hey that’s a fascinating read! Thanks for the link! Have you or anyone else tuned in your shock resistance yourselves? I can definitely tell if a car is over dampened, but it’s hard for me to “feel” for the sweet spot. Wondering if shop tuning is a must on this item. I need to get my height, track, and finally camber adjusted before I worry too much about shock acceleration resistance. I’m assuming toe should be neutral, but il read up on that topic shortly.

just thought I’d share something I made incase it inspires someone to give it a go. I fabricated a battery holder for my Braille unit last weekend. Sits in the passenger “hump” right behind where the passenger seat would sit. Made from 20 gauge 304SS. Made some minor measurements to get started, but used the battery as a template for most of the cuts and marking the bend seams. I don’t have metal brake, so I just used a straight-edge, various hammers (including a 2lb sledge) and locking clamps. As some of you have experienced, SS is much less pliable than mild cold-rolled steel, so it does take some elbow grease. I used a DA sander to debur the edges and get a consistent brushed finish. I’d say I did an OK job. It’s not great but it’s solid and should last forever. Only about $10 in raw materials. I didn’t want an 11lb projectile if I got in an accident, so I secured it to the body using tack welded nuts on the underbody, and eight 1/4” bolts to hold it down. I picked the location to keep the CG low, and as far back as possible. I considered putting her near the fuel cell, but I prefer the weight slightly in front of the rear wheel vs behind at a higher elevation. some of the gap you see between the battery and the holder will be padded with a thin sheet of EPDM to cushion and eliminate any rattle. as always, open to your thoughts and criticism! IMG_5406.MOV

How much of am improvement is the double vs. the single adjustable RACE Koni's? Its a big jump in price, and I was curious just how big of a difference it makes. For example, @gnosez described the huge leap in lap times going from a helical to a OS-Giken adjustable clutch LSD. I wonder if anyone has a similar experience between the single vs. double adjustment.

@rossman Here is a tip, but first my qualification. Started welding 5 months ago. Made many mistakes: going too fast and warping thin sheet, blowing holes, lots of pin-holes, proud welds that need a ton of grinding. First thing I learned is the welder DOES matter, and I now know why. A Lincoln Electric 140 (for example) is what I have now. It either feeds the wire at a consistent speed, or 100% stops (temporarily). This means when you hit a hidden spot of rust, or your arch is losing a solid circuit, the wire keeps traction in the machine or worse, bind. The gun may push back on you, but the wire will still feed. You get fewer holes, and the puddle is flatter when welding on super thin or shit base metal. Other thing i learned the hard way, turn UP the wire speed on thin wire (0.025). like, way up. I'm at 6.5/10 on fire feed on 2/4 power. probably be 2/3 that wire speed if i was running 0.030 wire. If you are getting a consistent frying sound without pulses or hissing, its probably spot on. Then try to turn DOWN the wire speed as much as you can just before you get the hissing. Welding with a consistent snapping arch at the lowest speed you can gives you a nice flat puddle, but still feeds enough to prevent the wire from prematurely melting on the tip. Turning up the speed from this point only serves to give you a prouder weld, and more grinding. The breakthrough for me was turning UP the heat. I now weld 20 gauge on 2/4 vs. 1/4 power. It takes LOTS of practice not to burn through. The huge payoff is no holes! the puddles flow out, fill cracks, and the back-side of the weld shows the puddle made it 100% through the base metal. I rarely ever need to go back and fill pinholes anymore. I still get burn-through in spots, but as you get better you also get better at filing them in. I can now fill 1/4"+ gaps in 20-gauge entirely with a Mig, the the metal deposited does not exceed the thickness of say... 14 gauge. Not ideal because you are burning gas and wire, but sure beats cutting a custom sliver. Yes it needs to be ground flush, but with a flap-wheel its quick work and looks like there was no gap to start with. il post some pictures as an example if it helps. To be clear, i am NOT a great welder or a professional. No formal training, just hours an hours or trial and error. I thought this might give you the confidence to experiment and see what works for me. I feel like im finally getting my stride.

Almost forgot... you will start wearing out the stock driveshaft U-joints (non replaceable) and diff front mount around 250+ft-lbs. I went through many driveshafts before having a custom one made. There is a great solution for the R180/200 front diff mount on the market now for about 100 bucks

i agree. I mean... for anything over 250hp working from scratch, LSX is hard to beat for a cost effective build. The rest is personal preference and secondary considerations (like efficiency). Once you break your Nissan 5-speed, the only reliable upgrade I have found is a custom bellhousing for a CD00X tranny from a 350/370z. If you feel like breaking more trannies, they are practically giving away Nissan 4-speeds here in Socal. if you are not driving this every day, then fuel economy is not an issue and LSX makes sense. you will need to consider an LSD regardless, but especially starting at ~200ft-lbs (for a light 71’) you will not keep traction in first. Many options here, and all that are worthwhile start at $1000. You will find a handful of threads I started in the last 6 months on the topic. those of us keeping the L28et is for nostalgia/preference or we already have upgraded parts over several years.

Just to be clear, the stock pistons+rings MIGHT do OK with a low enough static CR. For example, I never ran stock L28 dished pistons with the P90. I believe there are folks on here who have and did not express ring wear issues. There just isn’t much margin for error. L28 dished pistons + P90 head is your best case. P90a is a great head but has hydraulic lifters which are expensive to replace. You are also unable to adjust lash, and therefore are restricted for the stock cam (again, OK for up to 400). If you go forget pistons, you will need to machine your cylinders and rings to tight tolerances. (Not a bolt-in swap) While you are at it, you can overbore. Think of the L-series as a “truck/utility” engine when comparing it to modern engines. It is extremely reliable, over-engineered (extra metal thrown everywhere), extremely easy to work on, forgiving, simple, heavy, and inefficient. RB25 is more efficient (big plus is DOHC), but I don’t believe the stock block components can handle that much more torque than the L-series. RB26 is a huge improvement on stock component reliability, but they are expensive and harder to find now. Is this going to be a daily driver? Here is just my opinion on what I would do. Remember, 1000 ways to skin a cat: 300HP - L28et (if you have access to cheap L28 with a P90 head) for great torque and a lot of fun. You can even run a T3 super 60 and have pretty quick throttle response. SR20det for lighter and better handling at 300hp, but probably more money. I don’t have experience here. F20C for even lighter and better handling track car (but not intending to be competitive in spec racing) at 200-250hp. 400HP - RB25det + fuel, turbo, IC mods 500HP - RB25det with either RB26 internals or aftermarket components. 500+HP - just build an LS and consider some form of forced induction. almost any of these engines can make 500+HP, just with varying amounts of money and reliability.

Many thanks John! @jhm I will take this feedback and run with it! I found 3/16” inverted flare lines with 10mm metric threads at O’reily’s, so I should be good on the lines. I plan to get the tees and any misc. fittings from McMaster Carr or Fedhill like you mentioned. as always, it’s the little things right? Still waiting on my 3/16” “rubber” lined tube clamps to come in from amazon. I need to weld-in some #10 nuts in the tunnel and underbody to mount the lines. Most of the existing mount points were either cut by my predecessor, or by me so I could eliminate rust. I’m going to share a single mount point for the brake and 3/8” fuel line for simplicity. thanks again for it all your help guys!

As @NewZedmentioned, I’m just now getting back into the turbo L series world again after a 20 year hiatus. I have added a turbo to an L24 (twice) with independent EFI, and built an L28et as well. The only other consideration not mentioned by him are the pistons. The turbo pistons have the first piston ring further down from the crown. I believe the purpose was to move them further from the combustion gases since ring failure is much more common due to excessive heat caused by elevated cylinder pressures. Aside from flowing better, the P90 will give you a CR around 7.5 on dished piston L28 block. This is also an important consideration. I blew both my L24 turbo engines due to a combination of detonation and high chamber temperatures (L24 ran an 8.6-8.9 for e31 and e88. Detonation gives you a dramatic failure, while high temps on cast/stock piston+ring combo will wear out over a matter of months. The key word here is RELIABILITY. If you want an engine that will last you 100-200k miles with your torque needs, invest in forged pistons with modern ring materials. The rest of the crank components will handle 350-400ft-lbs of torque no problem. If you get your hands on a core L28, you can build a reliable engine for 6k. I recommend aftermarket manifolds (pro tuners for example) if you really want to hit the 400 mark. You can hit 300 with the stock manifolds @ 16-18psi but you will need a better downpipe. Look into 2.5” quality intercoolers (I am looking into water cooled), an indipendent EFI ($1-2k), and a quality turbo (Can’t go wrong with Garett). There are many little things you will need to change and upgrade as well, but that will get you started. For example, the stock 4 or 5 speeds start becoming unreliable at 300-400 ft-lbs torque IF (this is key) you actually can grip/launch in a low gear. If you are sliding all over the place (which you will without an LSD & soft, wide tires) the 5 speed will be OK. Mine lasted 8 years but I never had the traction. last thought: going above 400hp, an L-series starts to get expensive. You start to get diminish returns above this with the P90, even when it’s ported. It just doesn’t flow as well as it needs to. One primary consideration is an RB, LS, or VG/VQ/VR engine can be fitted with a reliable high-torque transmission without customizing a bell housing.

yep! You can apply it on top of the epoxy too! Even after coating, it’s not a bad idea to apply wax or a stable/thick oil such as lanolin into inaccessible areas. Can’t hurt just don’t use something unstable like WD-40. It will eventually break down over time and will not keep its surface tension indefinitely.

Thanks John! I'm going to stick with this valve for now (unless someone else has negative feedback) since I can easily change it out later. I also already made the mount for it to be accessible through the center console (see pic). if I understood you correctly, I can run brake lines directly from the master cylinder to tees leading to each wheel? If so, I just need to keep track of which reservoirs feeds the front vs. rear brakes? The proportioning valve looks like it just restricts pressure to the rear wheels, unless the previous owner installed it incorrectly.

Hi folks! The race car came with this guy in the cabin. It was crudely installed, so I just fabricated a mount so the brake lines can persist in the tunnel and not run into the cab like they are now. Is anyone familiar with this valve, and is it any good? It looks like what MSA sold years ago. im also confused how this works with the OEM brake balance/manifold in the engine bay. I took the valve apart, and it looks to be a simple spring loaded globe valve with an an adjustment knob. Not too dissimilar to an adjustable fuel pressure regulator. Just want to make sure it’s not junk since I’m going through the effort. Thank you all in advance! -Aydin

You are absolutely correct. Since I posted this, I went back and checked the rule book. No way this will compete in ITS. It has been lightened extensively. No way I can add-back 200lbs to meet the min weight, amongst other things. This car will continue as spec EP, but will qualify for some other vintage specs (beyond SCCA). If I race it myself, It will likely be vintage club and maybe SCCA vintage racing, as I don’t have the time to train or funds to compete in EP (at least for the time being). I had a great conversation with @gnosez and he was super helpful! Going to take her to willow springs when she is up and running.

yep! That’s the one! It is a bit of a stop/gap since applying epoxy by hand or spray directly is the best, but what it does is seep into the nooks and crannies (gravity). Since most moisture is going to splash-up from underneath the car, this will prevent water from seeping into your empty rocker cavity. That’s the worst-case issue with rockers rusting, is when they rust from the inside-out. It’s expensive, but just imagine how much more it would cost if you paid someone.

True enough. If you seal her up tight, there really won’t be a way for moisture to get in. You could also use one of the dimples on the cabin side to spray epoxy frame rail coating. Eastwood sells one for about 25 bucks. Comes with a wand. Good luck!

Looks great! I am envious of your space! Question: if you epoxy coated the hidden areas, wouldn't they burn when you weld it up? You must just be very careful. I just used weld-through primer on the hidden parts I knew I would be welding to.

that makes good sense. Looks like this will be the “entry level” racer 😂. Still like you said, but improvement over open.