onagao

Hey guys. I know this is a popular mod and a lot of stuff has been posted on it already, but I figured I might as well post my personal results.

I dyno tested my 2006 350Z 6MT a couple months ago with the following mods:

JWT Popcharger
Stillen HFCs
Stillen True Dual Exhaust

My results at the time:

Max Power = 255.35
Max Torque = 237.91
(Dynojet)

---

With the new MREV and Spacer installed, the car pulls like train in the midrange. My butt-dyno isn't exactly calibrated, but I can safely say this is the biggest difference I've felt so far. Sound-wise, there are only two noticeable differences. One, the engine note is a little deeper and perhaps the slightest bit louder (it's hard to tell with my other mods already on there). Second, the whistle from the intake (popcharger) is much, MUCH more noticeable. It's prominent throughout a large portion of the RPM range. For better or worse, it sounds almost like it's turbocharged. I haven't noticed this issue with other cars, but then again I haven't heard this setup on other cars. I'm thinking it can be attributed to the popcharger, but beyond that I'm clueless.

I'm heading back to get my car dyno tested tomorrow afternoon, and I should be able to have a comparison of the before/after dynos with some solid numbers to show. I'll see if I can get a video of it, too.

If anyone here has any input, opinions, advice, suggestions, or just a random $0.02 to add, please do.

Get_Zwole

iTrader: (34)

nice man dont forget to post numbers

onagao

For sure. If I can, I'm going to post an overlay (assuming he still has my old numbers on file). I actually just rescheduled my dyno test from tomorrow to in about 45 minutes. I really shouldn't be as excited as I am.

keithman5000

iTrader: (4)

I have the same whistle with my CAI it only happens are partially open throttle. I think what mine is could be a small air leak in the gasket...just my issue but its nothing that would ever cause a problem.

Get_Zwole

iTrader: (34)

nice man you should be wrapping it up soon cant wait to hear the numbers.

onagao

So I got some good news and some bad - potentially very bad - news.

First, the good. As expected, HP and TQ numbers went up significantly throughout the midrange. I don't have exact calculations as to how much was gained in the midrange... because I was too distracted by the bad news to ask. You can look at the chart and get a rough estimate as to how much they were, though.

New numbers:
262.10 WHP
252.47 WTQ
[VIDEO]
[BEFORE/AFTER CHART IS ATTACHED]


So that's the good news. The power and torque increases are right up there with Motordyne's advertised numbers. I'm actually quite happy with them.

Here's the bad news...

My car is running EXTREMELY lean (around 16). I don't have any previous A/F ratio data, so I don't know if this is a new development. Regardless, the numbers are alarming. The guy who was running the test said that it was extremely dangerous to run this lean - that within months, my rings could go out, etc. He said he definitely wouldn't get on this car in any hard way, given the situation.

So here I am with a bittersweet feeling. On one hand, the numbers met my expectations, and I'm happy. On the other hand, I could have a very serious issue on my hands.

So please, anyone, help me out here. I don't know how to deal with a problem like this. I have a few options that I can think of:

1) My brother suggested that I reset the ECU, even though I had the negative end of the battery disconnected for several hours - long enough to erase my radio presets (which I thought was an indication of ECU reset).

2) I could go in the direction of an ECU reflash - Uprev Osiris or Cobb Tuning AccessPort.

3) I could follow the advice of the guy at the shop and look into a new fuel injection/management system.

I really don't like #3. #1 doesn't seem like it hasn't already been done. And #2 will cost a substantial amount of money. These are the only 3 things I can come up with, and I don't know if any of them will help. That's why I'm asking anyone and everyone for some advice.

Please help.

Escobar

iTrader: (27)

I'd go with a reflash. Should fix the problem and give you better numbers.

Hydrazine

iTrader: (53)

Your power plots look really good.

I'm thinking it is much more likely that you may have a small air leak somewhere upstream in the exhaust system.

During the scavenge phase of the exhaust pulse, small leaks can actually pull air into the exhaust flow stream. When fresh air mixes with the exhaust stream and flows down to the dyno A/F sniffer, it will give erroneously high readings.

A/F 16 is seriously high, so high that the car would run lousy if it really was 16 inside the cylinders. This is what is suggesting its more likely to be an exhaust leak.

I went back up to your original post showing your mods and saw the Cats and Catback so that fits the scenario.

Its more likely that you are running fine, but in either case, you have to find the source of the problem sooner rather than later.

Start by checking for an exhaust leak. Put the car up on the lift while its idling and search all over the whole system carefully. It may be as simple as a couple flange bolts that need to be tightened up.

Tony

PS - The Stillen exhaust uses slip fits crushed together with U-bolt clamps. These slip fits leak almost all the time. ...If you were able to find a way to seal everything up, I'd bet your A/F will go down.

Hydrazine

iTrader: (53)

To help locate exhaust leaks:

Take a 3 foot length of 1/4" ID vinyl tubing and slip fit one end if it onto a 2 foot long piece of 1/4" OD copper tubing.

This will be your leak detection stethoscope. Place the vinyl tube next to your ear and use the copper tube to poke it around suspected leak areas. When the copper tube is placed near a leak, you will hear a loud increase in noise coming from the vinyl tube.

You can also bend the copper tube to reach around corners and other hard to reach areas.

onagao

Oh, I really hope you're right. That's some really fantastic advice. I will be sure to check that ASAP.

Unfortunately, I don't have a lift. My Nissan dealership is really cool, though, and they were the ones to install both the HFCs and Exhaust for me. If I call them up and ask them, would I be correct in assuming they'd have the means and know-how to perform a thorough check?

Mazinger Z

iTrader: (49)

Sweet man, nice numbers, hope you find out what's wrong.

Hydrazine

iTrader: (53)

Probably, but not necessarily.

Its like any shop. Sometimes they can have experienced mechanics and other times they can have techs that could care less.

You could do it yourself with a set of jack stands.

kenpo_350Z

iTrader: (15)

Very nice numbers! That turbo charged sound is def. from the intake. I get the same thing. Sounds cool just wish it was the real thing lol. Thanks for posting the numbers. I think I have buddy talked into the MD 5/16. These posts help.

Escobar

iTrader: (27)

+1, just jack it up and do it yourself. Be thorough and find the problem. It is more than likely a leak from the stillen.

Get_Zwole

iTrader: (34)

great numbers man good curve. Hopefully Tony is right that would be great if it was just an exhaust leak. I was always a little concerned about running lean too. Once i get fully modded ill grab a reflash.

HondaKiller

iTrader: (5)

your numbers dont really look bad, your A/F is whacked but honestly you may be paying too much attention to final output numbers. That mod is mainly to fill the cracks where the stock design fell flat.

You can smoke the exhaust to find a leak also, pull intake off with smoke machine let it suck that good chit down )

onagao

Well, I would have felt more comfortable having done it myself, but I don't have access to a jack... so I went down to my dealership and asked them to check for an exhaust leak. They're a good dealership, and they do a superb job, so I trust them with this much.

They had three guys look at it, and they found nothing. They said there was a bit of a sound coming from the right cat, but other than that, nothing.

So here I am. At least it didn't cost me anything, and I got a free car wash out of it.

I don't really have any more answers. I may still check it myself just to be sure, but certain things aren't adding up. Like Hydrazine said, the car would be running lousy with that A/F ratio. Now I don't necessarily know exactly how that would be, but it makes intuitive sense. So I have a few questions, now. Maybe you guys can help me. So far you've been a lot of help (thanks for the compliments about the numbers, too ). Here we go:

1.) What kind of noticeable effects would I feel or hear if the car really was running at that sort of A/F ratio (16-17:1).

2.) At what number would I get a warning light? It seems that if it's a dangerous level, the car would be telling me this... which makes me think that maybe there was something wrong with the guy's sensor or method.

3.) Speaking of sensor, Hydrazine mentioned a A/F "sniffer". What is the standard method of monitoring/measuring the A/F ratio? It's possible the guy did something stupid or unreliable.

4.) After leaving the negative end of the battery unplugged for as long as it was, the radio presets were erased. Is this a solid, reliable indication that the ECU was reset?

The car feels fine. It feels great, actually. I'm going easy on it until I can figure out what this problem is. Any help?

Zero350z

To the OP did you install the MD spacer yourself and if not, how much did it cost to install if you dnt mind me asking? Thanks

onagao

I installed it myself the same time I installed the MREV2. If you have to appropriate tools and read the instructions, it's a really very simple installation. I took my time and had no trouble with the whole thing, and my only previous experience was installing a JWT Popcharger (if that gives any perspective on my background with working on the engine bay).

Hydrazine

iTrader: (53)

Pinging. Sputtering. Misfiring.


At that level it would probably throw a check engine light. It would also show up with a code scan. Your dealer should have done a diagnostic check. That would tell you what the real A/F is regardless of what the dyno shop finds.

I suggest going back to the dealer to ask them to do a quick code check. Even if you don't have a CEL, they will be able to tell you what the real A/F is.

Possibly.


Yes.