speeder

On a new Megasquirt (V3.0, MSNS, Version 29V, low impedence injectors, PWM installed on the board, no dropping resistors) install on an L28ET, the engine started right up, sounded good, although too rich. I was busy tuning to get good idle/free-rev and suddenly the engine died. Everything checks out - good tach signal, injector common volts at the injector plugs, scoped 3Msec pulses on the other side of the injectors during cranking, but no fuel being injected. Going back through my calibration I find that, although I have set the PWM current limit to 30%, I have neglected to reduce the PWM time threshold from 25.5 Msec. I disconnected the ECU and, with the injector common active, momentarily grounded the other pin of each injector, and they all opened and injected fuel. Setting the PWM threshold to 1Msec and rechecking the scoped injector driver outputs with injectors connected, I still have good looking injector driver pulses, but see no PWM action on the waveshape. I swapped in my identically configured spare ECU and saw the same symptoms. I removed my wiring harness and verified all connections solid - They are. All injectors read the correct 3 Ohms resistance across their coils. That just leaves the injectors being the problem, and I have ordered some more. But I'm still puzzled at the indications. Back to the question: By missetting the PWM, have I damaged the injectors in such a way that they work with the old voltage test but do not when pulsed by the ECU? I'd also like to know what the injector driver signals should look like when viewed with a conventional oscilloscope rather than Z-ya's excellent current representation. Thanks for any input...

Reminds me of the decision I made a while ago to redo my trusty '78 daily driver. I just sucked it up and started to cut out rust and got prepared to replace rockers, fenders,etc. I still don't know where I'll find the time to complete this....... I feel your pain Bro.

With a cast iron turbo exhaust manifold, the best way is to not use a gasket. Get your manifold milled straight at the head mating surface, put a bead of the high temp copper silicone around each runner opening and install with no gasket. Do not use this technique with tubular headers. Believe it or not, this does work! Maybe something to do with even heating of the two pieces (head and manifold) by metal to metal contact. The ZX turbo manifold's runners have a tendency to flex and move around when heated. Upgraded studs and nuts wouldn't be a bad idea, either - member Pallnet sells a set I think. I obtained one of his sets as a drawing prize at SEZ and it is of the best quality. By now those old stock studs are probably ready to be retired. This is the only long-term solution to turbo exhaust manifold leaks I've found. The stock Nissan gaskets don't last, and the soft, metal -cored Fel-Pro ones are better, but only slightly. I looked for, and never found, a copper exhaust gasket for the L.

I have some - Gimme a PM.

$ sent. Thanks!

Second (or Third) the HKS EVC-EZ. The newer ones, though pricey, are just as good as the old ones.

Before I undertook the job of molding Z headlight buckets into my fenders, I investigated various aftermarket headlight assemblies to install. I actually obtained Miata, Eclipse, and PT Cruiser headlights to eyball - Finally gave up because it would be extremely difficult to line them up to look and function well. Headlights from another application, unless you get really lucky and find one whose contours match the Z, would probably be much more work than installing stockers.

I too am waiting for some timeslips and details of this setup. School me, daddy.

I'm still reading and thinking - you guys can probably smell burning horseshit from where you sit. Based on what we have seen so far, I'll close off the rear of the cowl bulge. There is far more evidence that the cowl opening is counterproductive to radiator flow than otherwise. I would be willing to bet that the air intake from an open rear cowl is always counter to air entering the underhood area through the radiator, but the net effect will vary according to speed. I think that these two sources of air intake will behave differently as speed varies, with the net flow through the underhood area varying with the vector sum of these inlet sources.This will explain: i.e. Sometimes the flow from the front is greater than that from the rear, but they still oppose each other. In the following case there is probabaly a stronger flow (bigger front inlet area?)from the front than the rear: I agree that the hood-popping data strongly suggests that venting underhood air to the foreward/side is effective in reducing pressure. If there is another wind tunnel session, I would really like to see a stock hood instrumented to give us a pressure map across its entire surface. I will also make large openings through the inner fenders to the side vent area of my front fenders, in addition to getting the radiator sealing and ducting done as has been discussed - but it looks as if proper hood venting is a large piece of the solution. I haven't yet considered drip rails and A pillars-

I used Ferreas in my 3.0l Turbo L6 and they have worked well. My Machinist says they are among the best valves made. My intakes on the P90 are stock size and the exhasts are +1mm. I had to special order the "extreme duty" valves- Don't remember any part numbers, however.... Unless you have serious head work (and probably eybrowing the block to unshroud the larger intake valve) , a larger intake will not give you any benefit and may in fact hurt performance. There are gains to be made from the larger exhaust in a stockish head, however.

Shady, My wife and I are fans of the Japanese dogs, especially the Shibas. Your post inspired me to take a couple pics. Ruby was rescued from a shelter 100 miles away - We found her on the pound's website where her parents were well documented, and were intrigued by the mix and appearance - We were not expecting the size, as she was 5 months old and already 35 pounds with huge feet! Ours was the third home she'd had because the previous owners were not ready for the famous Shiba exuberance, which is where she got the biggest part of her personality. At 4 years old and about 70 pounds, she's finally starting to exit the wild puppy stage. I've never had a dog so utterly devoted to me - don't know what that says about her judgement and intelligence....

This is Ruby. She's my shop companion, Shiba Inu/Shepard mix. People stop by the shop just to visit her. .

I've heard / seen this also. Is this not conflicting data? How is popping the hood different from having the rear of the cowl open? At present I'm about to close off the center rear of my cowl hood - I need the cowl for intake clearance but want to improve cooling and aero.

I had an uncle who flew P51s. Among many of his stories that amazed me as a kid was the account of how he liked to find an excuse to use "combat emergency" power. Seems that his Merlin had a 2-speed gearbox driving its supercharger. Push the throttle all the way forward to break a safety wire and now your supe is in high gear/ boost and you're haulin' ass. According to Uncle there were indicators that the crew could monitor to tell when this feature was used, and it would flag the need for a very much shortened engine rebuild interval. He said that you better have a good story for the crew chief or you were in for a butt-chewing. Without a doubt WW2 aviation provided a great amount of engine technology that we take for granted today.

I don't go there very much, but check out what they're saying on the "other" board: http://www.zcar.com/forums/read.php?f=4&i=334786&t=334786 Some people don't have a clue.

Lockheed YF12 Blackbird. I was up close to this badass a couple weeks ago at the new Air and Space Museum near Dulles airport. Simply amazing. It looks even more sinister in person than in pictures.

I tried all of the same, and even installed a different gauge, hoping the reading was wrong. It wasn't. I got the same results - The fat mixture helped the most but isn't the solution. Like you, I'm beginning to think that a "solution" isn't coming (or needed).

Tim, I'm following with interest your EGT numbers - I've tried everything I know to get mine below 1650F (20 psi on my 3.0l L, making at least 125 hp less than you make ) without success. Although I don't have a lot of time/miles on my junk, It has also held up well, but does freak me out. In my experience, and backed up by conversations with Scottie, the Buick guys report lower EGTs (1500 and lower) due to the long distance ( a couple feet!) most have between the exhaust ports and the EGT probe. Your dyno guy may have been talking about aftermarket exhausts for the Buicks that get this distance smaller. My manifold, an old BAE log style unit that has been extensively reworked and ported, has the probe mounted really close -about 6 inches away from the #5 exhaust valve. Looks as if your SFP unit has the turbo inlet fairly close, too.

You should be! That's just incredible, Tim.

Dan, I need to get over there and admire that fiberglass art, and maybe shamelessly cop some ideas for myself. I too have those Reaction research side vents and am contemplating closing the rear and opening up the sides to ensure that air does flow out. Maybe Dan Juday can comment on the cooling performance of these vents as- is? I can tell you that the big rear opening in the cowl hoods (without being ducted to a sealed carb airbox) do indeed hurt cooling, and, as we now know, also affect aerodynamics in a bad way. I will soon be back into the itchy/smelly stuff to correct this.

Electromotive TEC2 on L6 turbo stroker, TEC3r (in work for the 1000hp, staged 12each 85-pound injectored Buick V6 swap) , Haltech F9 on the NA daily driver. Joe, come see me when you're down this way - I can do some tuning for you.

'Manic Mechanic' - ZZTop

Awesome car, Nice writeup. I just saw that article yesterday, and it may just cause me to keep subscribing to Turbo magazine. Since its origins in the Buick GN/Turbo Mustang days, that rag got really Ricer/Honda dominated for a long time and was buiding apathy on my part. It's very amusing to me how the S30 is getting to be an "in" thing with the JDM/Ricer guys. For a couple years now all the wing and fartpipe kids around here have been giving me the thumbs up when encountering my Zs on the road. Again, beautiful car!

Thanks for the credit, Jon.

Just saw this - some additional comments: I've encountered no problems with rear clearance using the combinations listed: 325/50-15 Drag Radials on 15X10 (28"tall tire!) 315/35-17 Radials (Cheap Sumitomos) on 17X10.5 305/35-18 Toyo RA-1s on 18X 10. The latter two are Mustang replica wheels with a 3/4" spacer on AZC 5-lug rear brakes, Ground Control coilovers with 12" springs. These are all pretty much temporary acquisitions for fit check and eyeball/measuring purposes. Hard (430 rwhp stick shifted) launches with the sticky M/T DRs have not produced any interference with the wheel wells, although I did have to trim the YZs' wheel arches to clear. No extreme cornering or squatting I could produce made interference evident with the other combos.These other combos are ~ 26" tall and have permitted lowering the car without producing any rubbing. I am still planning on acquiring some CCWs for the 18s - looking at 13" rear, 12" front with the proper backspace to eliminate all spacers before installing the big HP motor. The 305s will go on the front (The YZ front flares are huge) and I will get 335/30s for the rear. I'm sure you guys know this, but larger diameter wheels give you more clearance from the Z's spring perch, so backspace and width can be increased over a smaller diameter wheel. There's loads of room in both directions with the 18X10/305s installed. I hope this helps - We all see so many threads asking, "what size wheel will fit" and the answer is never simple due to individual hub/brake/strut setups, flares, and etc. The bottom line is that you have to measure your own stuff before buying those expensive wheels/tires.