No I saw it but I'd think you'd learn more in tuning, not porting. The manifolds thin were you need to port and you can only port match to the lower and tb's. Going bigger won't help anything if you're hitting a rim of another object. I believe the only way to port match is to have every item on hand. Every item can be slightly bigger or smaller so the z1 mani my not be 100% port matched to the TB's or lower. Maybe he learned this and why the hp might not be as high as his.

want to know the mods lool!!!

I'm interested in learning more about this VVEL tuning.

Me too. I want my tuner to copy it but if he isn't giving out porting secrets he sure as **** isn't going to give tuning!!

I did talk to my tuner the other day and I thought this was interesting...he tuned a older 370 and played with vvel and couldn't get anything after a hour he said. But then last week he did a 13 and got like 10hp. He asked me if I knew anything that changed in the ecu or something that attributed to it but I've never heard anything. Only thing I've seen is what Megan has showed with the nismo vs non and such.

It took a while for my buddy who tuned my car to make significant gains -- we had a few logical hypotheses about where and what to change, but even then, there is still trial and error.

I think the TSM absolute values are a bit high (CF's of 1.03 - 1.05), but the overall proportionate change is awfully encouraging.

I can only imagine larger primaries, lots of porting, and maybe some pretty oval velocity stacks on the intakes are involved plus lots and lots of playing with VVEL.

In short: massage everything so it improves flow and then step-by-step experiment with VVEL to optimize valve timing.

The limits of space under the hood can be worked around to some extent -- on my old Celica we had to chop out a bit of the hood frame to make a little extra room for an intercooler core -- but we still aren't really clear on what exactly was done on the test car, at least last I checked.

Actually, do you mind posting the uncorrected values (CF=1.0)? It had to be lower than 340 if SAE applied a 1.03 correction and yielded 340...? :confused:

I'm still more interested in the delta than the absolute values, but I always prefer seeing more data over less :)

Correct me if I'm wrong but correction factor is automatic and only has to do with correcting back to the target temp and humidity etc. In SAE the dyno pretends its really like 77 degrees I believe. If its 85 in the dyno room it's just calculating back to 77 which is why uncorrected is always lowest since it's the true number and was a hotter run calculation. Unless of course its 30 degrees in the dyno room, then uncorrected should be higher than SAE since it will drop power since at 77 a car should make less power than at 30. In std the target is like 66 degrees which is why it always reads higher, a cooler day would produce more power. If 100% is 77 degrees then the 0.05% you're seeing is just getting the uncorrected number back to what it would be IF it was 77 and perfect conditions in the dyno room. I believe this is why dynojets are so accurate when someone in the desert gets 300hp SAE and someone in Florida or high in the mountains also gets 300hp with same mods. It's because the targets the same. Only uncorrected would show who's city is best, but it shows with two people showed up same day same track they'd be 100% equal.

I can't recall the specifics, but that sounds about right as far as temperature.

SAE is definitely more conservative correction than any of the other ones, which is why I treat it as a lower bound estimate (and STD as an upper bound).

The corrections for SAE (or any other correction) can be < 1.0 if the temps are especially cold and so forth -- but whether they bump the numbers up or down, they are far from perfect.

I posted several dynos, same car, same tune, same shop, same unit, same elevation, but different weather conditions, and while SAE correction brought the values closer together they were still off by quite a bit.

The reason for consistency in dynojets is because it calculates power based on the speed at which the known (and held constant) weight and diameter of a drum is spun, rather than adjusting load based on roller or hub resistance, which will mean more variance from unit to unit, shop to shop, based on what settings were selected (although, arguably, load holding dynos are more precise for purposes of tuning because you can more easily target a desired load range in, say, a fueling map).

Dynojets actually back calculate torque based on power, I believe, which is kind of opposite to the way it would ordinarily compute these values, but it still results in considerable consistency because of the drum's values being held constant.

Anyway, where things get really tricky is when the ambient conditions assessed by the dyno's sensors don't quite match the actual conditions. So for example, you might have a sensor that reads a consistently hotter or colder than actual temperature and wind up with constant under or over-correction. So long as the sensor location isn't moved around, the variance will be consistent, so it all works out, but this is probably why some shops have dynojets that tend to be consistently generous vs. not.

Also, factors like air temps in cylinder, deviations in the garage vs. outside, how quickly various closed loop trims converge on target values, etc. can all create (effectively random, in this case) variance in measurement.

I'd have to look at the formula, but I've found that SAE seems to do most of it's correction based on measured air pressure -- you tend to see massive correction (1.05+) being applied to motors dynoed in higher elevation/lower air pressure.

I think cars dynoed in FL tend to get a bit screwed by SAE because we're at pretty much sea level here, but consistently have really high humidity and hot temps, which I've (anecdotally, admittedly) notice don't seem to impact the CF value as much as pressure.

Now of course, temperature and humidity will affect air pressure, but all things being equal, SAE seems to be more generous when air pressure is down even by a bit -- that definitely helped the TSM dynos -- relative to temperature or humidity as separate factors.

****, now I need to go look this stuff up to confirm... I think there's a fairly new SAE correction calculation as well, so that will probably result in some confusing results if one shop's dynojet software uses the older correction and another shop's dynojet uses the newer one for some reason.

Quick comment of note:

"The magnitude of the power correction for tests run at non-standard conditions should not
exceed 3% for inlet air or 3% for inlet fuel corrections. If the correction factor exceeds these
values, it shall be noted as a nonstandard test in accordance with 8.1. "

In other words, corrections greater than 1.03 (or less than .97) should be taken with a pinch of salt ;)

From this SAE document http://www.mie.uth.gr/ekp_yliko/SAE_...E%95%CE%9A.pdf

Also informative: Corrected Power

One more... this guy's a bit, er, eccentric, but he seem to know fluid and thermodynamics, and has a number of very useful calculators to play with
https://wahiduddin.net/calc/cf.htm

Final edit: I think the dynojet uses inches of mercury to measure air pressure, and apparently that is not ideal for absolute air pressure calculations... not my bailiwick, but something else to keep in mind. That wahiddun link talks about it... https://wahiduddin.net/calc/pressure.htm

You can also use those calculators and historical national weather service data to arrive at more precise corrections for dynojet readings in order to eliminate sensor readings that may not accurately model ambient conditions (example: My last dyno claimed Humidity was 19%... according to NWS it was more like 40%...

Interesting stuff. To see most accurate dyno setting do you have a favorite drag racing calculator? Last time I went near stock I was 106.5mph trap. Weight with me I wanna say with 1/4 tank should have been 3342lbs. That on the dyno was 280. A calculator I found said I should have 274.

Sorry for the uber-long rambly discussion in the last post...

I like the idea of drag racing (real or calculated) as the most meaningful measure of real power, but a lot of other factors come into play like wheelspin, conditions of the track, the driver, along with all the usual suspects, such as ambient conditions, so I usually take that with a pinch of salt, and just go by averaged recorded performance that people at the track report (taking into account their mods and trans).

That said, the values usually converge with dynojet readings, give or take 5-10 whp, so its just additional evidence that points to overall engine output at WOT.

I'll admit to also being a sucker for magazine recorded 0-60 (or, really 0-100 kmh) runs, as well as Top Gear test track laps and the like (see further http://fastestlaps.com/comparisons/n...ota_ft-86.html ). As I said, more data is usually preferable to less, so I like to have more info to go by when trying to figure these things out and meaningfully interpret them.

I think what I would advise anyone to do is that if they want to take the time, look up NWS data (e.g., temp, dew point, etc) for the day and time the car was run on the dyno along with the elevation based on location (easily googled) and then plug into the calculators at that wahhidudin cite and apply the derived CF to the uncorrected dynojet values. Then you can compare and contrast with the dynojet SAE values that were obtained.

Interestingly, checking on some my last ones, the dynojet applied pressure and humidity readings were way off as compared to actual weather, so I would have had a more or less generous correction on a few of them (and the typical dynoshop is hardly a sealed dyno cell...)

Looking at the TSM data, and assuming the car was run within a day or two prior to the posting, I got a 1.03 correction plugging in all the data.

I think that means the uncorrected would have been about 330, and an SAE of 340 is about right -- remarkable, and reasonable to be a little skeptical of without further verification given how high a value that is -- but legitimate and defensible from a measurement standpoint, at least based on what we were given.

So, yeah -- TSM, build some stuff, show more dynos to verify the claimed merits, and price it to sell!

Other important take away: Dynojets always use the same yardstick -- a huge source of variance on load holding dynos -- every time. Only the correction factor and actual weather conditions need to be checked/taken into consideration when drawing conclusions. For non-inertia type dynos, its going to to be much, much harder to compare and contrast across shops, units, etc.

my rev limiter is at 8200 and I hit it all the time at the track.

She did it again.... She made 361 😉

What dyno?

More info please. A lot of it. So much to learn. So much we must know!!

So..... Nothing to report after a bunch of ambiguous numbers and excitement?

very interesting. would dif. like more info

He hasn't logged on since the 29th.

Z1's dyno.

well.. i guess we can all just imagine what mods and the dyno graph looked like...

i imagine the dyno graph was white with a blue squigly line.... maybe red..

I think a lot of it comes down to some of your expectations. All of the parts on this car in particular can be bought and installed on your own. Then it is up to your tuner to get all the power out of them. Some of that comes with tricks that particular tuner has learned on the platform. No one is going to give out their own secrets. That would be bad business practice as then there would be no reason for anyone to have to go to them to get what only they know.

There are some good tuners scattered across the US. I am not going to ship my car to California for instance in order to get knowledge from a tuner out there that may have made further gains on the platform. It would be bad for me and other Central/East coast Z owners. But it would be great for all the West coast Z owners.

We don't all live in GA though. We need tuners and dyno's up here too.

This is what I hate about the Z community. The subi community had many hands in developing rom raider and still do to define definitions for FREE. We used the free open source tuning software and could get help from anywhere. All you needed was a $150 cable or borrow one.

Even free MANY MANY MANY!! People still go to tuners since they can't do it themselves or would even dream of trying. Uprev sucks making you pay $150-180 just to crack the ecu and since 90% of the population doesn't live in GA just share with people! If you don't have shitty customer service you shouldn't be worried about other tuners stealing your ****. People will still want to come to you for a pro tune on their car. Yes you may lose out of town business but unless you pay them $100 in gas to come to you, why be a hater when guys just want to save money? Be happy for them that they run your tune or the knowledge you gave their tuner. We are all here to enjoy the same thing and I doubt you'll see a income drop if you told your secrets. Locals will still pay and you can freely keep rapping GTR customers for $1000 plus tunes and $5000 CBE since their metal and bends must be so much better than ours for that price.

I think 361HP at rear wheels NA is total BS. So there I said it. :stirthepot:

Without a trap speed or a dyno run at a neutral site, I'm leaning your way. I'm not ruling it out, but when you beat the previous record NA numbers by 20whp and then go radio silence when people ask you specifics about what you did, it makes me wonder if that car would still be breaking records on someone else's dyno.

One run down the drag strip and all of the questions go away. It's really that simple.

i was trying to believe this all at first......but i really dont.

:bs:

Lol. Well it was std so figure the real numbers are 346-353. In for trap speeds too confirm along with weight of vehicle, fuel, driver.

I tend to agree. Stock these cars put down between 255-275 RWHP, right? Gaining ~100 RWHP without changing cams or increasing displacement? I'm having a hard time buying it.

You can make N/A gains of 100 RWHP+ in an LS3 Corvette, but you need CAI, headers with exhaust, very aggressive cam, U/D pulley, and possibly some head work. And that's in a car with 6.2L of displacement to work with. Making those same types of gains with only 3.7L and LESS upgrades seems way to good to be true.

Just pointing out....

Z1's shop car hit 356 rwhp. Doesn't seem that far off from this car's numbers,

So that's two different cars, with presumably similar mods on two separate dynos making similar gains.

Could just be the Georgia Air :rofl2:

or maybe both being :bs: ?

:stirthepot:

Z1's dyno is known to be "generous". So it's two cars with similar "secret" :rolleyes: mods making similar record numbers on two separate dynos, one of which is known to be one of the higher reading ones. That's why I hope they'll show us a trap speed.

Who knows, I'm just as curious.

I have no experience with top speed yet, but I do know Z1 doesn't care to bs much lol.

:stirthepot::stirthepot:

@ Chuck , agreed. Trap speeds would be beneficial

What we do know about both cars:

z1 headers
tomei single
tuned by z1 and former z1 employee

We all hope the numbers are repeatable. It's a good thing. We need people to push the limits of what can be done with this motor. It's just got to be proveable and repeatable. If it's just one factory freak car that doesn't help the community. If it's one of those things where you can buy their parts, take them to your local tuner and drop 350whp on demand, everybody benefits.

yea well first step in this is for them to talk about what is even being done with it and help out the community....which this is.

trap speed would be cool to see. it better be big for all this talk and "high" numbers. i mean with my tiny WHP i trapped pretty high a few times for N/A. interested to see if this will ever be shown.

The after HP # doesn't really concern me. I can make a dyno read pretty much whatever I want to read within reason. The only way to accurately measure HP gains is to do a before dyno with the same car and preferably on the same day (or as close as possible) as the after dyno. Comparing someone else's before dyno to your after dyno is pretty much useless.

What concerns me is that we are being shown a before dyno of 272 (correct me if I am wrong) and an after dyno of 361 (again, correct me if I am wrong) which means we are looking at a supposed gain of 89 RWHP. I'm sorry, but I don't buy it. These are either dyno sheets of 2 different cars and/or they were taken at 2 different periods of time. Show me the before dyno of the same car and the after dyno of the same car taken on the same day (or close to it) with all the other factors being the same, and then let's talk turkey.

Again, if I am wrong, please let me know, because I can't see the actual dyno sheets posted due to the firewall in place at work. I am just going on #'s that are being mentioned in the thread.

:iagree:

Most Nismos seem to dyno between 280-290whp, right? Work blocks most images here too- is the correction factor the same on both dyno charts?

The Z1 Dyno is not generous. Ive seen too many stock 370 put down 372ish and nismos around 385-390. Ive seen cars that should make power, make it and cars that have some issues not.

Its a dynojet. Same as TopSpeed's. Really no way to play with numbers unless they can control the environment. I think the issue most people have is that GA isn't exactly high altitude. So if anything, other dyno's read lower, but these 2 should be accurate.

There was a dyno day this past saturday. With alot of Z's dynoing. I missed the first 4 hours so im not sure what happened, but the numbers I saw looked consistant with the dyno's and mods.

372,385-390? do you mean 272, 285-290 i'm guessing?

seems like anyone with GA or ATL in their location spot are the ones backing all this. either it is something with the location or just friends helping friends lol

One run down the strip puts all this to bed.

yeah 2 lolol. 3 woulda been something.

Not backing them due to friends, backing them because i see all the dyno's constantly posted by people all over the country. Because my own car has hit multiple dyno's in the GA area also as have alot of the cars in this area.

and yes a run down the strip could prove something. But then again, a run on the strip at GA with 90degrees and 70% humidity will yield diff results than the same car same strip at 67 degrees and 10% humidity (and the way GA weather is, this could be the same day!)

GA doesn't have the market cornered on heat and humidity. Trap speed would tell a lot more than one overcorrected dyno plot with a baseline from another car no matter what outside temps are.

most people here will understand the ET/trap difference based on weather conditions if they list them. most strips post the current conditions on the time slip. not all but most do that i've been to or seen.