Leon

I'm surprised you'll be able to see the maps being used in real time with such an old ECU. I've only played with newer stuff and most of those don't seem to support it. Them again, I haven't gone as DIY as you either. Are you able to see the hex code for the entire ROM? It'll take some manual labor but you may get lucky and find the RPM and load scales near the address of the maps you've found. Looks like a fun project!

Thanks man, I appreciate it. I may want to copy your rear setup. I'm predicting the path of least resistance is going to be to slap the drums back on. I have zero complaints about the performance of the stock system as it sits currently. The reasoning behind the swap was (1) ease of service, (2) better cooling for when I finally track it and (3) might as well do it while I'm in there. This will give me some time to hash out the details.

@lowrider Rough measurements are as follows: ID @ hub face = 315 mm ID @ ridge = 355 mm ID @ barrel = 365 mm 30mm from hub face to top of ridge I'm having the inside of the wheel 3d-scanned at work next week so that I can mock things up. I can send that data as well.

Hey Matt, thanks! Funny you ask, I've been using his VF tubes for a little while now but haven't gone back to the dyno since I tested the Weber jetting. I finally measured my idle manifold vacuum (17mmHG) and thus ordered some of Keiths weak-vacuum idle jets. I'll be road-tuning my buddy's 3.1 this weekend for which we just bought Keith's jetting as well. Dyno tuning for both his and my Z will come in the near future, he needs to break in his motor first. In short, I will have a complete summary of how Keith's jets do vs the Weber stuff in not too long from now. It also seems like I have a fuel flow issue which I haven't dealt with yet. I've been meaning to replace my dinky O'Reillys thumper pump with the Mallory I bought, just haven't done so yet. Honestly, $300 for e-tubes and idles isn't that much when you compare to the iterations you have to go through with the Weber stuff. Plus, Keith has great support for his products and will refund you if you're not happy. Weber distributors won't do that... and if you find an ITB conversion for $300, I'm all ears! Frankly, I'd love to run ITBs for multiple reasons but I also enjoy the old-school character of the car and the triples fit that perfectly. I have other EFI cars to satisfy my itch.

Sweet setup! This is essentially exactly what I'm conceptualizing, nicely done. Do you have details on your conversion anywhere? I'll take some measurements of my wheels today. I have Nigel's kit, as seen here: http://forums.hybridz.org/topic/113199-yet-another-rear-drum-to-disk-conversion-option/ It's an 11.8" (300mm) vented rotor and a Lincoln LS rear brake caliper. Interestingly, it appears to be exactly the same kit as the Silvermine Stage 4 with some minor differences.

Thanks for the Coleman tip, Brady! Didn't think of them for brakes but looks like they have some good options for a DIY kit. I'd like to be able to rotate the tires and not sure I like the staggered diameter look but otherwise that would work.

It really depends on your duty cycle on track and how hard you drive on the street. Your tires' wear pattern will be the tell since you have such a mixture of use cases.

Glad to hear! That front toe setting really wasn't doing you any favors either, I wonder if it was incorrectly measured last time or if something had been changed since. That looks nicely dialed in, you'll want more camber depending on how much you track it.

Thanks Ryan, frankly I didn't expect the brakes to fit. Just thought I'd try and see what happens. Test fit was done with 8mm spacers, it would probably clear with a 12mm spacer but the wheel poke would be ridiculous. I took a quick look at T3, looks like their kit won't fit 15" R-Types. In any case, I'm considering sticking it out with drums for now unless I find a cheap rear disk kit to hold me over. The end goal is to size some calipers and machine brackets and rotor hats to essentially make my own brake kit. I'm envisioning something similar to the ZCG "Big-Brakes for small wheels" kit but with an integrated rear park brake instead of the dual calipers. I also prefer blank rotors, especially on a classic car. I'd like to swap the struts over before the 26th and at this point, drums are looking like the path of least resistance (and cost).

The struts are ready to go in! Laid down some paint and pressed in the bearings and Nissan Quest wheel studs. The bad news is that the rear disk conversion doesn't fit the 15" wheels... 😕 So the disk conversion is now for sale and I'm figuring out what to do about the rears. I've decided not to go back to drums so I'll be looking to get rear disks that fit under the wheels in relatively short order. I'd like to drive the car to Laguna on the new setup for the Monterey Historics on the 26th.

Well, turns out it don't fit! Anybody interested in buying this kit off of me? Everything is brand new, rotors are already re-drilled for 4-lug. $650 takes it.

Well done! From a glance of that first tabulated timing map, looks like the RPM axis is vertical and the load axis is horizontal, if your testing hasn't already showed that. Looking forward to seeing how far you get!

Welcome! Looks like you've got a nice Z to play with. As the others, I'm going to question the goals first. I can understand the street/track car goal but the other two seem more like requirements rather than goals. The 250-350hp is a requirement in order for you to achieve something. That something might be a certain lap time around a track, or a quarter mile time, or bragging rights at car shows, etc. The more bizarre goal is the highly-specific compression ratio. Why is that a goal? To figure out your start and end points, it's going to take a lot of sifting through info online. Some of the info is good but most is iffy at best. What the sifting absolutely will do is improve your search-fu and show you other things you should be searching for. Once you've wrapped your head around what it is you're doing, it'll take some iteration to figure things out on your own. This requires a willingness to spend extra time and money that you didn't anticipate spending and forego some instant gratification. It's never perfect the first time. I'll link you to my build thread at the bottom of this post. The work I've done to my current Z represents what I've learned by hanging around Z forums and Z folks the last 11 years, doing some learning on my own, and working with other talented people. Engine-wise, it's a somewhat basic L28 build that made 195whp which is worth approximately 234hp at the crank on that specific dyno. The thread is a complete build log and as good a starting point as any to figuring out what it is you want and need. Ross's advice above is bang-on. I will contend with one point, my engine ended up at 11:1 (not a goal but a result based on my requirements) and I run it on California 91oct at 35 degrees of timing advance without issue. http://forums.hybridz.org/topic/111062-leons-other-260z/

I do it with the engine running for the most representative results. Here's my process to setting floats: - Warm up the engine, make sure it's in good tune and not shaking at idle - Pull one main jet stack out of each carb - Measure and record float levels, take multiple measurements for greater fidelity - Shut off the engine and remove the float covers - Use a caliper to measure the distance between the float and float cover with the float tang just touching the float valve - Adjust the above measured distance by the difference in measured and desired float height, it's a 1:1 relationship All it typically takes is one iteration when using this method. SKs and OERs that have externally adjustable float levels still need a course adjustment on the tang but are more forgiving due to said adjustment.

I know your pain, high performance tire options for wide 15s are slim. Toyo does make R888R's in 235/50-15, a buddy is running them on his 15x10s. That's what he settled on after we researched the hell out of the current options. The other contenders were Hankook RS4s in 245/40-15s and Achilles ATR-K in 245/45-15. You're not going to find decent 255 or 265s unfortunately.

Go for slight toe-in at the rear, 0.10-0.20 degrees total.

"Good" depends on your use case. Are you tracking it and how strong are your arms? Take a look at John Coffey's recommendations, they're in the first post of this thread.

In a vacuum, both toe-in or toe-out would cause dartiness as single-wheel inputs will steer the car one way or the other. I also don't agree with toe-out being better for turn-in, as it decreases your yaw rate gain, i.e. you need more steering input per given corner radius. Now if we take ourselves out of the vacuum, there are other effects that influence static toe settings such as suspension compliance (mostly controlled by bushings) and kinematics (bump-steer). I haven't seen any published K&C test results on an S30 chassis but if you've installed poly bushings everywhere, keeping toe close to zero with a dab of toe-in, as you have it, is a safe bet. The cheapest way of adjusting rear toe with stock arms is eccentric bushings. I've never used them but I don't see any other way around that other than adjustable arms or doing a bunch of fab work to slot the transverse link supports and splice in a turnbuckle into the transverse link brace (this has been done and can be found by searching).

Higher caster should have more of a centering effect due to the increased trail which increases the aligning moment on the tire. The caveat is that with the steering geometry of the Z (including but not limited to), there's a point where steering forces reverse and there is a wind-on effect where the wheel steers itself towards lock. This is all a long-winded way of saying that bringing caster back down will not improve your return to center problem and that return to center will suck no matter what, when you reach a certain critical steering angle. However, I haven't studied the Z's geometry that carefully so I very well could have overlooked something. Adding more front toe will make the car dartier, that looks good where it is. The added negative camber may make the car dart a bit more but it's a smaller effect than toe. I really think that rear toe is doing you wrong plus maybe some other mechanical factor that we haven't found yet. Have you checked your steering system for slop (ball joints, rack, etc.)?

So did anybody end up trying this setup on 15" wheels?

I made an opportunistic purchase today! I've fantasized of going to 15X8 Watanabes (I know, so blasé) for years. A buddy tipped me off to a fresh set for sale locally and I decided to go for it. Really looking forward to seeing how they fit the car and keeping my fingers crossed that they'll work with the rear disks that I'm about to install. So now that this has finally happened, I'll have to liquidate a few things from the hoarde...

Strange, I wouldn't expect steering feel to dull after increasing caster/trail. It comes down to what you mean by dull steering feel. Is it the steering feedback that's dull or a lack of body rotation per steering input? To me, it sounds like the latter and should be helped by reducing your rear toe. A huge front bar and no rear also doesn't help.

That's a lot of rear toe. I would dial that back to no more than 0.10° per side. Do you have your previous alignment specs to compare to?

I'm not so sure about that cantilevered rod-end boss. That's a fatigue failure waiting to happen...

Cam timing looks ok and shouldn't cause the issues you're seeing. The shiny links are used to set timing on chain install, the groove and notch are used for all other checks and adjustments as OP has done. My money is on a calibration or crank sensor issue.