bradyzq

Disclaimer: I am a dyno tuner! I would say that it is worth it to get your car onto a dyno along with a good tuner. Here's why: It's not as if when you put your car on a dyno that it will automatically run better when it rolls off, or even that there is much you can do to a stock 260Z on the dyno, BUT, the dyno is IMO the best place to see how your car is currently running. In other words, it'll highlight any problems the car might have. The dyno will also allow you to experiment with mixture knobs and timing to determine what your car likes best. So I definitely say, "Go!" Worst case, if your car turns out to be running perfectly before you even get on the dyno, you'll leave with some dyno graphs of your car and a good baseline for future comparison. Best case, problems will be identified and hopefully corrected, and your car will run much better than it did before.

I am glad to read that this looks as if it will be resolved happily. But I am surprised I am in the minority in thinking Calgary Z did everything right! If I was 2500km away in another country and I had a problem, I would at least have a local expert have a look. Not necessarily work on it, but have a look. For many reasons, the main one being having the information to tell Dave Rebello when he asks what went wrong. IMO, the only guy who should feel put out in this scenaro is the first shop in Calgary, cuz he won't get his big job out of this. Sounds like he deserved to be let go though.

Right, but compressing the charge will multiply the pressure by 8 or so.

Well, you could vent the block breather too, with a bigger K&N. That's the way mine has been for years. Small K&N breather on the valve cover, and a bigger one on the block breather pipe. Of course, now you have two filters to clean instead of one. Another option is to use some kind of exhaust evac system, like the old drag racers. That would give you a greater pressure difference across the rings, and maybe a bit more power as a result, if it's legal in your class. Basically, you are using exhaust flow as your source of vacuum, instead of post-throttle intake manifold.

It hasn't been explicitly mentioned in this thread, but having a vertical flow intercooler, aside from having MUCH more flow (HP) capability than a horizontal flow core of the same dimensions (umm, well usually, unless they're square...), will also allow you to have your endtanks feeding into and leading out of the intercooler on the same side, so you won't have to worry about charge piping across the front of the engine. Of course this is not an issue if you find a crossflow or twincam head!

Your power numbers represent at least 275HP crank plus or minus fudge factors. To compare, your wheel numbers are within 10 of a stock 350Z's, and that's supposed to be a 300hp motor! Basically, WOW. Sounds great too. I aspire to that sound for my Z, but with triple Weber intake moan thrown in.

MONZTER, Nice, smooth power curve. With REALLY good numbers! Couple of questions though: Was there an orange (at least mine is) thermocouple cable from the dyno in the engine compartment or anywhere else? Maybe coiled and hooked on the side of the dyno control tower? Also, what is the correction method if any? I've heard of a shop that tells the dyno it's measuring ambient temperature, then proceeeds to put the thermocouple under the hood. Since the dyno thinks it's measuring ambient temperature, it uses that number in its correction calculations, resulating in way high numbers if it gets hot enough. I once showed what had happened to a customer who was not able to duplicate his numbers from another shop (also had a Dynapack, like me). I figured it out when he told me where the themocouple had been placed. We tried it, and gained over 30WHP IIRC. Which would STILL leave you with sweet numbers! How fast is your car at the drags?

Found out what "engine" is. It's just an 8 bit "code". 17, which shows up in your datalogs, means the engine is running (1), and TPS enrichment is active (16).

Harry, Haven't looked at the msq because I don't have Megatune on this computer (Mac). Good idea on replumbing the WG signal to the intake. In theory, if the issue is the wastegate fluttering, it should happen about 1 psi or so higher up. All along, I've understood that the miss/stumble WAS the drop in boost. To confirm, does the car do anything other than have uneven power delivery for a second? Is there a real miss, as in a cylinder not firing? Also, do you have AFR logs somewhere, or were you watching a gauge? And what is Column I, labelled "Engine" in the datalogs? Whenever it is not "1" there is some TPS accel enrichment, even though TPS is 100. For the dyno, you can completely turn off TPS accel enrichment.

Harry, Well, maybe it's bad grounds. After all, it's a voltage difference that we're measuring. Do you know if the voltage across the battery agrees with the MS? I suppose I should have suggested checking grounds first, since in the Megamanual, they beat it to death. I looked at the the second datalog, and the same thing is true. Most of your dyno pull is at under 13V. Even while idling after, most of the time the voltage is way too low. Oh, yeah, I assume your O2 and EGT are just not hooked up to the MS since the numbers make no sense. Back to the wastegate. On both datalogs, the boost "bounces" twice, once a lot, and the second time a lot less. And it happens the first time the boost hits 185ish kpa. It's only 7-8kpa or 1psi away from max boost on the datalog. The wastegate may very well be starting to open by then. Are you SURE your wastegate is not sticking (not able to close again fast enough) a bit? Or maybe your boring out of the wastegate has made it less progressive?

Harry, I just looked at the first datalog, and the only suspect thing I see so far is that your battery voltage drops below 13V right around the time the problem starts. May be coincidence, but later on in the run, the voltage drops into the LOW 11's!! Something is up here. Is your alternator good? Loose belt perhaps? All EMS's like/need good constant voltage. A lot relies on a good 5V sensor reference, MAP sensor included, or 12V for actuators like fuel injectors. They'll open more slowly when underpowered. I know there is a voltage compensation bin in the MS to take care of this, but it's REALLY not ideal to be running using it. I'm not saying this is the problem, but definitely fix the voltage issue now, because it may be causing other issues.

Harry, I'll look at the logs soon. It's too late now, but I suggest that one ALWAYS log MAP and AFR on the dyno. It only takes a couple of minutes longer to set up, and maybe a couple of bucks more, but it should give you confirmation of your numbers at the very least. That, and you have two sets of eyes looking at these valuable numbers during the runs. It's just one extra safeguard. BTW, this is what I do for a living. I tune on a Dynapack dyno. I don't have huge amounts of experience with MS, though I just built one for one of my old Audis, and have tuned a few for customers. I guess that MS experience will shoot up soon though!

If I understand correctly, when you removed the intercooler, the problem went away? Even with way higher intake temps? But theoretically with 1 psi or so more boost. Hmm, loose hose clamps maybe? And did you physically remove the BOV? They are guilty of leaking under boost fairly often, though one would think the turbo could overcome such a leak... I haven't downloaded your zip files yet (am at wrong computer), but what is your max boost shown? Is "boost" from the dyno and "MAP" from the MS? Anyways, what I'm getting at is that your wastegate may be sticky. Does this happen when you're first reaching max boost, but smooths out afterwards? If your WG spring is 15lb or about 200kpa, and if 185kpa or about 12.5psi is the max boost you achieve (not counting any boost creep later on), then you may have another issue too. You're losing over 2 psi from the turbo outlet to the intake. Just throwing out ideas here. Hopefully one will help!

Do you have a boost controller, or is the wastegate spring a 14 pounder?

Well, if it started happening when you swapped BOVs, try removing the BOV, blocking it off, and going for a datalog run. Maybe the BOV is leaking badly.

What does he mean by "the sunroof has been deleted?" I hope he means that it just doesn't work....

Another opinion you may or may not want... You have a VG30DE, as in NOT TT, as in not easy or inexpensive to make big power with? I fudguesstimate that you would be better off, in terms of downtime, AND expense and maybe even power levels, if you threw your time and effort into building up your L28.

Hi All, Great, now hopefully revived, thread! Though anti-reversion has been discussed already, what are your thoughts when relating to turbo engines? In turbo applications, pressure in the exhaust manifold can be much higher than in NA apps, so I'm wondering if exhaust port liners could keep the combustion chamber cleaner (better scavenged due to blocking the burnt mixture from re-entering up the exhaust port). Is it more black and white than in NA apps? Or is the answer still "It depends on .... Helmholtz, ..... turbine specs, etc?" Thanks.

No it wouldn't. But, in addition to the exhaust, a 6-2-1 header was added, as well as more timing and smaller main jets, which look like they took away a rich bog. So, it sounds much more possible, especially when, as previously noted, one notices that torque is in Nm not lb*ft. Actually, I'm kind of expecting similar gains when I finally get my L24 on my dyno in the spring.

If you are going to pay for a test to be performed on your engine, I would suggest a leak-down test. It will tell you a lot more than a compression test (which you should also do anyways). With a leak-down test, you can find the source of compression loss (intake/exhaust valves not closing completely, head gasket leaking into coolant passages, etc). That test could cost $100, though I hope it would be less. It would probably be charged on the clock since the test is much quicker if you don't have to find the "leak-down" (IOW if the engine is in good health, it'll be cheaper).

Yup.

I've got a couple of suggestions, but they're not for shops in the area, since I live thousands of miles away in another country.... I think you have separate issues to address. 1. Your car HAS to get out of that shop, ASAP. Since he's not buying your parts, how can he make progress if you leave it there. 2. I wouldn't look for ONE shop to do al the rest of the work. Consider segmenting the tasks. Bodywork to a good bodyshop, engine work and maybe other mechanical work to a competent mechanic, and EMS tuning to a good tuner. Wiring may be best done by the EMS guy or mechanic, depending on how far their competencies go. I have yet to see a shop that excels at all of the above. They may DO it all, but well? AND, if they do, can they coordinate a schedule so that your car goes right from one section of the shop to another without a significant wait in between. Also, overwhelming projects tend to be done only in down time, because they take up shop space for extended periods of time. My qualifications to make these suggestions? I am an EMS tuner with a dyno, set up right next to a very competent mechanic and bodyshop. As an example, we got a car from another shop because no progress was being made, and the car was a specialty of the other shop. The car, now running and tuned about 80%, STILL took months, and there was progress every week. Assembling the engine, EMS wiring, getting all the other parts, getting the exhaust fabbed, suspension, clutch/flywheel, making stuff fit.... and finally EMS tuning. No bodywork, BTW. If that had to be inserted, it could have stretched the timeline significantly. Oh, BTW, before you get your car tuned, make sure that the car is mechanically, and electrically perfect. It will save you money at the tuner's and make dealing with him much easier. We HATE having to deal with bad wiring, and worn out/broken parts. That, and asking a tuner to tune around a problem is a waste of your money. HTH!

Have you considered using the valve cover vent instead for your catchcan? It has a smaller diameter.....

I have no advice for you on finding/making a triple manifold, but I do have some on "ruining" a car. It's your car. Do whatever the *&%# you want with it! And enjoy it. You could even fuel inject it, a la 300SL (well, not really that way) to piss off the purists even more.

How is your pressure regulator plumbed in?