z-ya

15x8 Sportmax with Toyo 225-50ZR15 R888 tires:

Exactly. Bigger has to better, right? For an all out max power NA motor 300cc/min if more than enough (280cc/min turbo injectors work great for this application). For turbo, 450cc is a good place to start if you are tuning for more than 300WHP. I'm running 370cc/min on my turbo motor that makes 300WHP and I have plenty of head room. Remember, the larger the injector, the smaller the opening time at idle. Some injectors are kind of lazy at opening times of less than 1.2mS or so, which can cause a poor idle that you cannot tune out. It does depend on the injector though. Flow rates are not linear with opening time, and this is especially true with newer high flow designs. These newer injectors can produce a smooth idle and deliver the high flow rate when needed. As far as low Z injectors with a resistor pack, I have never seen a problem MS. Use the PWM if you don't want to use a resistor pack. Pete

Good catch! Pete

Dave, Those bolts loosen up on me too. Typically after I swap the diff, and after few hundred miles, I need to tighten them back down. 300ft-lbs at the wheels tends to move things a round. Is the gear noise you hear similar to what I described? Thanks, Pete

Dave, I drove my car for the first time this year the other day. I definitely do not have the clunking sound you have. I can get on and off the throttle without clunk. What I do have is a gear noise that I can control with the throttle. Under full load there is no noise. Only when cruising can I make the gear noise my modulating the throttle just the right way. I wonder if a heavier oil might quiet yours down. I'm using 75W90 conventional in mine. Pete

I didn't say it can't be done. It just takes a lot of expertise, and a lot of time. My point is that there will most likely be an area in the powerband where the optimal AFR cannot be achieved without affecting other areas. So typically for a racer you will focus on WOT tuning, because for the most part, that is all that matters.

I don't see how the final part will be over sized. If you make the mold correctly, it will spit out a mirror image part of what the mold was made from. This is how molds are made. You make a model of the part, and then wax it, gel coat, and then 3-4 layers of glass for strength. Pop the original model from the mold, trim, wetsand any imperfections, and you are ready to produce more parts.

Yea, I'm thinking bumpers too. An alternative to re-chroming, maybe not. But as a new look, yes! I really like the creamy-silver look of jet hot coating, and I think 240Z bumpers would look great with that finish. I'm wondering what clear urethane would do to it? At a minimum it's a cheap way to make new flatware for the Wife! But seriously, nice work Dave! Pete

You don't really need the Zed Findings rails if you are using the Bad Dog ones. Pete

I usually run 75w90 Mobil 1 or Valvoline full synthetic. I've also run conventional 75w90 when that is all I had laying around. I think you just had some components that were ready to fail. Pete

What are your PWM settings? You need to enable PWM to drive low impedance injectors without resistors. What injectors are you using?

Put the shroud back on, it makes a huge difference. I've taken an old nasty shroud, cleaned it up, and painted it and it looked great. I did this on my wife's 280Z as she NEEDS AC! Pete

Being in Florida, and having AC, I would keep the stock fan and shroud. It will push more air than any single electric fan. You will need to run dual electric fans to equal what a single engine driven fan can do. And then you will be drawing a lot off the electrical system causing more of a load on the alternator, and therefore the engine. You don't get something for nothing. Just make sure your fan clutch is working properly. Pete

I think you need to find a new transmission guy. There is no reason why a Z or ZX 5-speed cannot handle extended road racing with a 180WHP L6. Now if you were making a lot more power, I would look for something stronger. We run a 1980 280ZX NA 5speed in our road racer. We have been running the same transmission for at least 3 seasons. No problems whatsoever. We change the oil twice a season usually. The owner of the local transmission shop that rebuilt it for us worked on a Datsun race team in the 70's, so he knows these transmissions quite well. Find yourself a new transmission guy and keep a spare in the truck. Pete

Do you have a resistor in series with +12v and each injector? If not, what are your PWM settings? Pete

Should this turn into a vanity plate thread?

Derek, Given the condition of your motor, you'll make about the same power with your custom TBs vs. the stock SUs given the same AFR at the peak power RPM point. The RPM where it makes the most power might be slightly different between the two setups, but the power will be approximately the same. You need to build yourself a new motor to really take advantage of your TBs (hint, hint...). I suspect that your TB setup would be comparable to a set of Mikunis or Webers as for as power potential. A budget upgrade would be some flat top ITM pistons, a fresh valve job and a medium cam. If your cylinders are in good shape, you shouldn't need to bore the block. This would yield a 10:1 CR, and at least 180WHP. Time to upgrade! Pete

Do you have a ground from the engine block to the battery? How many and what size ground wires do you have in the cable between the relay box and the Megasquirt?

Where is the relay board getting power from and what gauge wire have your for both ground and power to the relay board? You should have the relay board power tied to the battery., not another circuit or the starter/alternator. Pete

Have you sanded the primer? If you sand it with 320 grit you should not see where the filler is. Once you get the sanded primer layers the way you want, then spray a sealer coat. Pete

I think your right. It sounds more like the OBX than the R&P. It more like a clack, than a clunk (technical terms ). The mechanical noise you are hearing is the same noise I have. The Nissan CLSD is quiet, the OBX is noisy for sure. I've driven a car with the Quaife, and it is quiet BTW. Pete

Get the OEM Mitsubishi module for that coil pack and save yourself a lot of headaches. The easiest way to determine the correct max dwell is to measure it on the original running engine it came on. That is fine for max dwell, but what about coil discharge time? The best thing to do is characterize the max dwell and coil discharge time on the bench with a scope and a pulse generator. I can do this for you. PM me if interested. Pete

If it is your first coat of primer, then I would not reduce it, but only add the correct ratio of hardener. Keep adding coats and sanding until you are happy with the primed finish. Then I would reduce it with 1 part acetone (like 4-1-1) for use as a sealer. Then the color coat. Pete

Dave, It sounds like ring and pinion gear slop to me. Did you check the lash in the ring and pinion before and after replacing the differential? With mine, we had to re-shim the carrier to reduce the ring and pinion slop and to prevent the ring gear bolts from rubbing the differential housing. Mine makes some gear noise (not a continuous whine), but has minimal clunk when getting on and off the throttle. I have the RT mount in there too. Can you feel any slop if you rotate the drive shaft while holding one of the half shafts? Pete

I'm using 2K urethane (high build) primer after the filler was block sanded. It works great in filling all the filler sanding scratches. The first coat I mixed 4-1, then sand it with 150 grit. Then I put another coat with 4-1-1 ratio and sand with 320 grit. The final primer coat is mixed to 4-1-2 and it is ready for the color coat. So basically you are using the 2K primer as a sealer when you mix it 4-1-2 (primer-hardener-reducer). The 2K urethane primer sands easily, and and you end up with a super smooth surface for the color coat. I'll post pics when I am done. Pete