TimZ

One of the biggest reasons for the Ferarri sound is that they use a flat crank. In other words, the firing sequence alternates between cylinder banks evenly. This doesn't balance as well as the 'normal' uneven firing order, but it makes exhaust tuning much more effective. If you are using a V8, you could approximate it by using 180 degree headers - these cross the exhaust runners over to get back to an even firing order at the collectors. I would guess that this would be fairly difficult to fit in a Z, though.

The restrictors do more than just prevent oil from building up in the heads - they are most likely there in order to maintain oil pressure at the mains.

Yup - as with the Pinto, the 'design flaw' was most likely having a gas tank in the first place. Go take a look at the back end of your Z and the placement of the tank. Tell me that it wouldn't rupture under the same circumstances (especially those of you that have removed the bumper for appearance).

You know, I still felt like sh!t this morning (Monday) In spite of the several hours out of the middle of Saturday, I enjoyed having James come to visit - we'll have to do that again, sometime... Or maybe I'll come to Florida and make you ill next time...

Thanks for the kind words, guys... Sorry I've had a lot of 'stuff' going on lately, and haven't had much presence here for a while. James pretty much nailed the details on my setup. Those dyno runs were the high boost settings, as James stated (don't want to start any urban legends ). I did do some low boost runs earlier in the year last year - I only made about 280-290rwhp on ~9lbs of boost (95degF ambient temps in the dyno cell that day, BTW). The T-series really seem to like running at higher boost pressures. The car did get a makeover last winter - I've just been getting it back together. Still white, no more 'parking lot strips' on the sides, and street flares and bigger tires. 255/40-17s in the front and 275/40-17s in the rear. Traction seems much better, now. I'll try to get some pics taken soon.

I took a slightly different approach: http://www.hybridz.org/ubb/ultimatebb.php?ubb=get_topic;f=12;t=000261

Well, nobody else has mentioned it yet, so I guess I will... The manner in which you 'bed in' the pads can have a huge impact on their performance, regardless of which pads you choose. I saw at least one post in this thread that alluded to not being able to lock the brakes with a fresh stock braking system - I suspect that the pads weren't bedded in properly, since the stock brakes should still be able to lock on a single stop. If you get performance pads, they will probably include bedding in instuctions for the specific pad - follow them. In lieu of instructions, I usually follow this procedure: 10 moderate effort stops (~0.3g) from ~15mph 10 moderate effort stops from ~35mph 10 moderate effort stops from ~50mph 5 higher effort (~0.6g) stops from ~50mph Don't leave alot of cooldown time between stops, and try to drive the car a fair distance above 40mph after the procedure is done, avoiding using the brakes to let them cool back down evenly. The low speed stops can be done just about anywhere that traffic is light. The higher speed stops take a bit more planning.

No - Pete is using the Wilwood Spot Calipers for his e-Brake: Wilwood Spot Calipers The setup above is a drum-in-hat e-brake. I've often thought that would be a nice way to go. Might take a bit of engineering to fit one of these to a z though...

Sorry to rain on the parade, but I'm 99.9% sure that a simple resistor network will not work. The reason for this is that the peak-hold type injectors simply require more current to open (hence the 'peak' part of the name). Generally, this is considerably more current than the drivers for a saturated injector are capable of delivering. Adding resistors to the circuit will only reduce the amount of current sent to the injector. I believe that what you will need to make this work is a solid state, high current amplifier that triggers off of (or replaces in the case of the EEC-IV mod noted above) the original saturated injector driver's output.

Well, sort of. First, rotational inertia is proportional to the square of the radius of the pulley on it's rotational axis. So, since the radius of the pulley is maybe a fourth of the radius of the flywheel, reducing weight here will only have about 1/16th the effect of reducing weight at the flywheel. Not very cost-effective.If you want to reduce rotational inertia, go to the source - the flywheel. Second, and more importantly, a good portion of the weight of the crank pulley is isolated by a rubbber strip, which makes it act as a vibration damper. With the long length of the L6 motor's crank, there are known problems with crankshaft failure above ~8000rpm, due to torsional vibration. Getting rid of the vibration damping provided by the crank pulley will only make this worse. The UR crank pulleys might work okay on L4 or V6 motors with relatively short cranks (and I think that's debateable), but they are just a bad idea for an L6, IMHO.

Some amount of blowby is normal for a turbo engine. The more boost you run, the more blowby you will get. This is why I have oil traps in my PCV lines... The y-shaped piece takes the oil out of the blow by gas and drains it back to the oil pan. If your ring lands look okay, and your compression/leakdown test results look okay, then you probably just fall into the 'normal' category. How much is not normal? If you have a broken ring land, you will probably see enough blowby for oil to start leaking out around the oil filler cap on the valve cover. If it's not doing that, then I wouldn't fret too much.

Sorry James - I ASSumed that you LOOKED at it before you installed it...

Maybe check your fuel pressure regulator - there should be a vacuum hose connected between it and the intake manifold (if it's there, check it for leaks). If this hose is missing or disconnected, the engine will run rich when off boost (will probably still idle okay), and go lean when on boost. Sound familiar?

Well, it looks like everybody has already gone over my setup, so I won't bore you with that... One thing to note - my engine is NOT a stroker - it's a plain old L28, with Cunningham rods and Arias pistons. I'm not really convinced that for a turbo application the stroker crank makes that much difference - the displacement is only about 10% larger - this can be made up with about 1.5 psi of boost. As was already noted, John's motor makes it's power at relatively high rpm, and since it's intended to be a track car , will probably expect to see a pretty large percentage of that 50 hours at 6000rpm or higher. The inertial loads imposed by sustained high rpm operation is what is mandating John's service requirements, not the power level. With a turbo setup, you generally make your power at significantly lower rpm (my hp peak is at ~5200rpm, torque at ~4200), which is less stressful on the rods. As far as trying to turn 8500rpm with a turbo, my guess is that you'd be pretty hard pressed to find a cam grind that would allow you to make significant power at that rpm - turbo engines don't generally like alot of valve overlap, due to the reversion caused by the high exhaust manifold pressures that the turbo creates. If you found a turbo with low enough backpressure, it probably wouldn't spool until 5000 rpm or higher. Finally, if you are having traction problems at low speeds, you should also consider that maybe your gearing is not matched to your engine. Shorter (higher numerical) gearing is not always better or faster for a given setup. If you have lots of low end torque, you might be better served by a taller gear ratio, especially if you don't have particularly large tires.

With the stock N/A block (I'm assuming L28 here), the P90 should yield a CR of about 7.4:1 with the stock head gasket. Going to the thicker HKS gaskets would yield CRs of 6.5 (3mm) to 6.9:1 (2mm), which is too low, IMHO. I'm currently running ~24psi on an N42 block with no problems. I am using forged 7.5:1 pistons at that boost level, though. For the stock cast pistons, 7.4 CR, a decent intercooler and proper fuel delivery and ignition timing, you should be able to run ~12psi (maybe 14) with no problems. If you really want a metal head gasket, then you should use the HKS 1mm gasket, which will yield a CR of about 7.5:1.

I'd be careful here... I doubt that Corky meant to try this on the engine while under boost. You can check this statically by monitoring the fuel pressure while applying pressure to the FPR reference port with a MityVac pressure tester (or equivalent).

Probably a good idea to make sure that the head is torqued properly. Also, I'd recommend re-torquing a bit more often to make sure it stays that way.

Mostly pointless, unless you are running very low boost pressures. As I recall, the stock turbo pump has an internal pressure relief at either 60 or 65 psi, so it will never go higher than that. For the RR FPR to work properly you would want the capability of going much higher than that (like 100-120psi). Also, when picking out a new pump it's VERY important to make sure that the pump will supply enough fuel at the fuel pressures you intend to use. There can be a HUGE difference in flow capacity when going from 45psi to 100psi. Many high flow FI pumps won't even go that high.

Yes, it's driveable, but if it's really missing the front swaybar, then the car will be prone to oversteer. You should exercise caution in driving it until you can get a new bar...

Blk - that's pretty much the theory behind them, and the Turbo Mag tests did change wheels and tires between the installed/not installed tests - the better tires were on the installed test. So as far as that test knew they could have (and probably did) made the stopping distances worse. I have been involved in ABS design/development for some time, and I know that at least one major ABS supplier has investigated these. They didn't work.

quote: Originally posted by blueovalz: But one thing that always puzzeled me is if 14.7 psi is all that will "push" the air into the turbo inlet, than how can so much more air be forced into the cylinder vs the same 14.7 psi pushing the same air into the carb (which has a bigger cross section opening). My take on this is that although you are correct in stating that ~14.7psia is available at either a carb inlet or a turbo inlet, the actual pressure differential across the carb is not 14.7 psi. On the contrary, for a carb at WOT, the manifold pressure is very close to atmospheric (zero vacuum), so the resultant flow through the carb is only due to maybe 1 or 2 psi of pressure differential at most. My guess is that the compressor blades cause a much higher pressure differential at the compressor inlet, hence the higher airflows. On the big cams thing - the assumption that long overlaps don't work well because of the fuel/air mix getting 'blown through' only holds for supercharged engines. With a turbo, the opposite happens, because the exhaust manifold pressures are almost always higher than the intake manifold pressure. This is due to the backpressure produced by the turbine. The problem with long overlap cams and turbos is actually due to exhaust reversion.

I would say that you have turned a very important corner in your understanding of forced induction. You are on the right track - boost pressure is more of a symptom than a cure. The pressure is what results from trying to force a given CFM through a given restriction. If you have less restriction, you can have the same flow at lower boost pressure. The flow is really what determines how much power you make. This is more obvious with a supercharger than a turbo, since with a turbo the wastegate controls boost pressure by modifying the flow.

As I recall, the Motorsport stroker kit yields an unsuitably high compression ratio for forced induction use. Do you have a plan for dealing with that?

I believe the Kumho V700 Victoracer was the tire that came in 265/45ZR-16. This would be a much more suitable tire for the street, IMHO, and still very competitive. A friend of mine used to autocross with the Hoosier autocross tires, and they didn't look like they would last five minutes on the street. The construction was extremely light - they sounded like balloons if you flicked your finger on them . They were very effective for autocross, but he swapped street tires back on when he left the race course.

quote: Originally posted by Hydra: Ceramics are an awesome engineering material, So many advantages to them. Problem is they're very expensive not to mention brittle. My pistons and exhaust ports were ceramic coated by Swain, and I have had excellent luck. The coating is very tough, and I have not seen any problems assodciated with brittleness. The price was very reasonable, too. Detonation resistance? Well, I can't say that it's the coatings for sure, but I am able to run 24psi on 94 octane pump gas...