I dyno'd my car again Friday. The only changes to the car were the used stillen intake I got from Russ, and my crawford cats that I put back on. And the catch-can.

Last time I dynod at a new location. I really liked the shop, and the guy was a pro. So that's where I went yesterday. Last time(late April), the ambient temps in the garage hovered in the lower 70s. Yesterday the ambient temps were pegged at 103.

I didn't expect huge gains. But I can't complain. In april, my max numbers(5th gear, SAE, 0 smoothing) were 254.66/243.49. Yesterday, the max numbers(5th gear, SAE, 0 smoothing) were 259.13/246.52. The gains weren't overwhelming, but I saw a solid 3hp/tq everywhere, except around 4500 and again between 5100 and 5500. I did notice that it knocked as soon as the operator got on the throttle, and it knocked again a few times right around 4500. Unfortunately, I don't have a monitoring tool, so I don't know exactly how much timing was being pulled. That's one thing for which the SAE corrections can't account, so I would have to assume that the gains would be even greater if there wasn't any knock.

A note on the knock: looking at the a/f, it appears the ECU is dumping fuel at around 4500. With the mods, I was running a little leaner than before between 2800 and 4500, then all of sudden it got progressively richer, mirroring the previous dyno's a/f readings.

Overall, I can't complain. But I really need to start looking into an ECU to bring it all together. I don't know how much power I can get from a piggyback, but if I can play with the fuel, and run more timing(safely, without knock), then I think there's at least another 10 to 15hp left. And because it's running so lean down low, I think I can really get back some torque on the low end as well.

I've attached a few graphs, as well as an excel spreadsheet with my analysis. It's zipped, not because of size, but because driver doesn't allow .xls attachments.

 

nice numbers, corresponds with the 1/4 mile time and trap speed as well.

 

You have me all confused since the all knowing forum expert stated the Stillen Intake doesn't work and the oil catch can doesn't catch that much oil.

Do you plan to redyno when it cools off? The results could be even more interesting.

 

Or not. Since conditions were a lot worse this go around therefore I'd assume the correction factors were a bit higher too. The higher/lower the correction factor, the more skewed the data gets. The closer the CF is to 1.00 the better. Once the CF is at .98 to 1.02, the numbers start getting skewed a bit.

Calculating the average gains across what many of us consider the powerband (4800-6800rpms), it appears to me that his VQ35 has gained about 3-4whp. There are some points that gain nearly 10whp, but from 5100-6200rpms, there's no gain. FYI, the most important place to gain power in the heart on the powerband, not over the far end above 6000rpms. Ideally you want to gain power in the mid portion because that's where the car spends the most time accelerating. In the end, I'd venture to say the car will be no quicker in the 1/4 mile, but I'm sure Trey will be testing the car in the cooler months to verify this. Trey's a smart guy. He understands all of this and I doubt he'd disagree with what I'm saying.

I've never said the Stillen intake won't gain anything (though I often do link a post the shows exactly that). I've always contended the Stillen intake reduces part-throttle response, part-throttle to WOT response, and has minimal/erratic gains which when calculated out amounts to a very minimal gain over the powerband. To me, Trey's dyno is neither surprising or eye opening. I've seen the same thing posted on this site and 350Zdriver.com over the past 3 years.

 

99.5% of all dynos I've seen peg the CF between .98-1.02. Are you trying to suggest that unless the CF is 1.00 the data is invalid? Didn't think so.


Don't fall off your bike backpedalling like that......you've made a career out of saying mods don't work. Don't pretend otherwise now.

 

Finally, someone else who's has done their homework, compared previous posts and sees the all knowing G35/VQ mod expert for who he is.


I've always contended the Stillen intake reduces part-throttle response, part-throttle to WOT response, and has minimal/erratic gains which when calculated out amounts to a very minimal gain over the powerband.

Always and never are very dangerous words, especially for those who seldom post same story twice.

As for the Stillen intake, how would you know what it does? Have you tested it on the special 2003 G35 sedan?

 

A note on correction factors. The runs in april had a correction factor of 1.0, while Friday's run had a factor of 1.04.

I asked the owner/operator about the significance of the correction factor. I was mainly interested because his dynojet is much much more repeatable run-to-run than the other in-town dynojet.

When I asked Blake, he just smirked and brought up some charts. He said he's always asked about the correction factor. His wife has an E36 M3 vert. He pulled up about 7 dynos of her car, with factors ranging from .99 to 1.03. The car was stock for all the runs, even down to the tires. I was surprised to see they all lined up exactly. I'm talking about variations within 1hp.

Take it for what you will.

 

I wasn't expecting huge gains, and I don't expect my 1/4 times to change drastically just because of the last two mods. But I do speculate that I've picked up around 2 to 3mph in the 1/4.

In the 1/8th, I was trapping 78's. That was with a slipping clutch, in the high 90's. And that was without the stillen airbox. I bet after I get my clutch installed, I'll be in the 79's, maybe the 80's.

Last winter, in 25 degree weather, I was trapping 79's and low 80's at the 1/4 track. This 1/8 mile track is a little slower(maybe .5 to 1mph) than the 1/4. So I believe if I went back to that 1/4 track(again, with a new clutch), I'd see 1/8th mile traps in the 79 to 80 range. If my car can gain 22mph in the last 1/8 like it does in the winter(I don't believe it can), then I'd be trapping between 101 to 102. That's what I was trapping back in december in 25 degree weather.

When it get cooler(again, in the 35 to 25 degree range), I think I'll pick up 2, maybe 3mph more. So that means in similar conditions to my 13 second runs last year, where I trapped 101 and 102(with a one time 103), I should be trapping 104 to 105.

It's not a huge improvement, but I can't complain about an NA 3500lb sedan running mid 100's with about 1k in bolt-ons. But you never know. I might not gain anything at all.

 

Hey, believe what you what you want. A friend of mine runs MCRacing that is a performance/dyno shop in Merriam, KS (www.gomcracing.com) and he's also an ex-ATI Procharger (Overland Park, KS) engineer. I tend to believe much of what he says since has been working with Dynojets for about 15 years now at his shop and at ATI.


Oh really, then what about this post from myself well over a month ago? It's only fitting my post was specifically about the Stillen CAI and it coincides perfectly with Trey's dyno results.

Post #12
https://g35driver.com/forums/showthr...ghlight=intake


I've stated my point and we'll let the masses decide. You, Earl, DaveO, G35-TX, etc can flame away at will. I'm not going to turn Trey's post into a mess. It has good information that people need to see and make the decision for themselves. I've never said ALL mods are useless. The question is if the gains are truely useful to the performance a car. A gain of 10whp from 6000-6500rpms isn't going to make the car perform any better in a 1/4 mile race. That's a fact.

 

Every post you post in becomes a mess.

 

Ah, but I averaged a gain of around 3.5hp from 5k to 7k. Remember, I can go all the way to 7200 or so. Which is the range I'll be in for 2nd, 3rd, and a good portion of 4th.

But even those gains will show meager results.