phunk

iTrader: (21)

Part 1

This is possibly the longest post ever posted anywhere and i had to cut it into 2 posts cause it wouldnt let me post the whole thing, but good readin for the n00b... I expect no more than 2-3 people to hold on to their sanity through this whole thing. Its more for me and im just processing my thoughts out loud.

It is all based on my personal experiences. If you have experiences that differ with mine... feel free. I would hate to look like a fool if I am incorrect somewhere.

I have read a lot of threads here about the SC vs TT and what not, and rather then reply to them all I just bundled up my ideas and personal thoughts and considerations. So it is sitting here if anyone cares to read. Everyone is talking about HP HP HP, but no one is talking about what these kits are doing to stop your engine from blowing up.

First I will go over why I made my premature selection on the Greddy TT kit, and why I will take TT over SC anyday. Then I will give my take on the fuel systems and tuning the 350z.

Why TT over SC? (all the reasons tend to revolve around the fact that the SC is crank driven and the TT is exhaust driven and controlled via wastegates):

1: More HP with less work from the engine. Twin Turbo systems, obviously, run off of spent exhaust gases. The only additional stress this puts on the engine is during the exhaust stroke of each cylinder as the exhaust backpressure has been severaly increased by the turbine housing... causing resistence to the piston traveling "upward" on its exhaust stroke. A supercharger hinders your engine with a 24/7 drag on the crankshaft. This drag is there no matter what all the time. This causes less RWHP at any given airflow value through the engine. I would say PSI rather then airflow, but for the techies that know, PSI is not everything, the density of that charge pressure is a HUGE factor based on compressor efficiency and intercooling.

A twin turbo Z, and a supercharged Z, both with 400rwhp... guess which one is getting better gas mileage, will last longer, and putting less load on the engine to produce those #'s.... your right.. the twin turbo car wins.

2: SC systems boost with less control. While they are consistent, there is less throttle based control. If you have ever driven a turbo car for more than a minute you already know that you can keep out of boost very easily if you want to. Not to mention the fact that a turbo system will allow on the fly boost changes with a boost controller.

A little bit of lag is good... I personaly find it annoying when I drive cars with tiny turbochargers... just trying to drive somewhat peppy and they are all up in my face boosting non stop just taken off from a light... relax little guy im just trying to drive im not racing anyone. Geegh, I definatly would have no appreciation for the superchargers always trying to boost on me.

3: Reliability. A WELL engineered turbo system, properly installed, will not need to be screwed with. SC systems commonly eat belts. I sure would be pissed if I lost a belt just when getting into a race. A turbo system using cast iron manifolds, reputable turbos, flex sections in the downpipes, blow off valve(s), and good oil feed and return lines can go a LONG LONG LONG time without any special attention providing you do not shut off the engine immediately after boosting hard often.

4: Noise, SC cars make a lot of noise. The SC itself makes noise even when you are just sitting there at a light. A turbo system can be very civil and go completely unnoticed if you desire and drive it so. Exhaust tone of a turbo car is typically much more toned and civil than a SC or NA car.

5: The ONLY downside from the turbo system is the LAG. Well... I drive turbo cars ALL the time. Instant spool up can be annoying, like I said previously. But at any rate... if you have owned a turbo car and played with it before, you know that turbo spoolup is pretty much instant at a high RPM.

So to those who are argueing lag as an excuse to not go turbo... when you are about the race someone on the highway are you sitting in 5th gear at 1500 RPM before you punch it? If so, you lost the race before it started. Realistically your sitting there in 3rd gear at 4500RPM waiting to punch it... do that in a turbo car and you got instant boost. EDIT: Removed misleading and sarcastic comment.


Why have I picked the Greddy TT kit over the ATI Procharger or any other?

1: Cause its a TT kit, of course.

2: The prices that everyone is throwing are MSRP. If Greddy products actually sold for anything NEAR MSRP... I would be a rich man. Expect about 20% off of what Greddy says it will cost.

3: The potential of the Greddy TT kit is astounding. With the turbos they selected, which I have used before... this kit can produce over 500rwhp if someone wants to push it to its limits... I will be towards the front of the line to push this kit to its limits.

4: Greddys fuel system offered in the 350z TT kit is the the best you can realistically do. Dont talk to me about standalone EMS' cause I already know about them and use them. There are a large number of factors that point to keeping the stock ECU in a 350z and using just a piggy back to tune. The ATI kit uses an advanced FMU, this has pretty much no appeal to me.

5: Reliabilty. The Mitsu turbos in the Greddy kit are very reliable. The cast iron manifolds will not crack. I have seen and run into problems with greddy oil lines and downpipes, and for this reason unless I see a change of trend with this new kit, I will be building new stainless braided oil lines and downpipes when installing my kit. So maybe I cant use this point against the other kits since I am already counting on making immediate changes.'

6: Upgradability. I will tell you now that it DOES NOT take 2 18gs to make the power that greddy is saying their kit makes. It takes 1. Since greddy kit owners will be so fortunate to have 2 of these turbos on their car... the potential is there to go for super big HP upwards to and possibly surpassing 500rwhp. The greddy turbo kit for the Civic Si DOHC 1.6L that uses 1 of these turbos makes over 250rwhp at 7 psi. The 350z has over twice the engine, and 2 of these turbos. Put 2 and 2 together and you know what I mean.

Thats all I can think of at the moment.

Fuel system options... There are basically 3 methods to get the fuel and spark tuning done right when you put a turbo on a NA car.

1: FMU (high rising rate inline fuel pressure regulator, or "Fuel Management Unit").
2: Piggyback (such as Greddy's E-Manage, or the Split Second unit)
3: Standalone EMS (complete indepentant engine management system.

phunk

iTrader: (21)

Part 2

Here is my basic list of pros and cons of each system. However first I wanna preach some tuning. I own a shop, and a dyno... and I tune cars. While I am far from an authority on tuning... I am not new to it. One thing I feel is WAY too far overlooked is ignition timing control... ESPECIALLY when puting a turbo on a NA car.

Too much timing melts pistons more often then too lean of fuel. The flame front from combustion travels much faster as pressure increases. For this reason you need to retard ignition timing so that flame front doesnt jack your piston while its still trying to raise on the compression stroke or while its still dwelling at top dead center. This is by far the hardest part of tuning, and I personally feel the most important as it will RAPIDLY destroy engines, or increase and decrease power quicker than anything.. and its actually difficult to get perfect. Fuel curves are pretty easy to get right when you have a wideband o2 datalogger.

Ive seen turbo hondas come in here with nasty lean fuel curves that have been running around untuned like that for a long time and still managing to hold together. And then I have seen hondas that have too much timing crack and melt off their pistons ring lands within a day or two. I am referencing hondas because I own a shop and hondas are by far the most popular car commonly converted from NA to Turbo. For this reason they go thru it all and have it actually figured out better (as a community) than anyone as these guys are not too uncommonly seen making over 400fwhp on pump gas from very small engines.

Fuel tuning on a car like the 350Z can be difficult when going from NA to Turbo. This is because it uses an airflow meter device. airflow meter cars are typically smarter and will self adjust for increases of volumetric efficiency until the point where the meter has been maxed out. This would be super awesome if the stock airflow meter could read up to 500hp worth of airflow, but i will promise that it cant.

Heres where the complication comes in: Say you have a FMU, a turbocharger, and an airflow meter that outputs 0-5v with 5 volts being max airflow. All numbers are just random here but you will see the point. Your cruising at 2000 RPM, airflow meter is readin 2.5 volts. You decide to give it a little go. You increase throttle, airflow readings increase, and the turbo systems starts to generate pressure. Airflow readings are at 3.2 volts well within the stock fuel systems limits. But wait.. you are at 2 psi of boost. Your stock fuel system is already injecting the needed fuel for the current airflow, yet your FMU is jacking your fuel pressure by an additional 24psi... hmm, your now running way too rich. Boost response is crap, gas mileage is crap, and there is a bog sensation to pull thru.

There are ways around this if you play around. Rather then having the airflow meter after the filter, you can put it after your compressor of choice. Assuming your airflow meter can handle the pressure, this can work well because the airflow meter doesnt see the pressure. I guess you could say it is seeing the "speed" of the air coming in, but not the fact that it is pressurized. Of course most airflow meters have built in air temp sensors so its also good now because the stock ECU has fuel and spark correction tables based on air temp... so letting it see that hot post compressor air is a good idea to help the sake of tuning.

So now where does that leave us? It leaves us with the idea that all we now have to tune out is the fact that the engine has a pressurized intake charge... rather then having to deal with the stock ECU making up for some of the boost some of the time... now it will never know its there and we can start with a clean slate. If the car ALSO has a MAP (Manifold Air Pressure) sensor somewhere on the intake manifold... then you have an even smarter car. But MAP sensors are easy to overcome. You can simply moniter the output voltage with the engine off, key ON, (0 vacuum, which is full load on a NA car) and then install a voltage clamp that never lets the voltage pass this point. The idea here is to protect you from check engine lights and limp modes.

Also... it wouldnt catch me off guard if the 350z had a voltage limit on the airflow meter as well, causing a check engine light and possibly a limp mode. This could be worked around as well if it just so happened to be true.

We can now use devices that alter fuel and ignition tuning based solely on boost pressure, just like a honda guy can (hondas dont have airflow meters).

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FMU Pros:
Easy to tune, if you call that tuning.

Will get you thru smog testing in most states. Lots of states dont even do a rolling test on the dyno if the OBD-II system is not storing any trouble codes. So no problems here.

FMU Cons:
No real tunability. Some adjustable ones like the aeromotive one used in the ATI kit is the one to have if you really must go down this path.

No ignition timing control!! Add an independant timing adjustor... something like the MSD BTM that can retard the ignition timing per psi of boost.

Jacked up fuel pressure... better make sure all those lines are tight and up to the job of regularly seeing over 100psi, which is over double factory fuel systems are designed to operate at.

Generally crappy boost transition. I havent seen one yet that doesnt go way way too rich just as the boost comes on. Perhaps that Aeromotive toy provided with the ATI kit doesnt have this problem. No experience with exact device.
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Piggy Back Pros:

I will focus this only on the E-Manage and Split Second unit (which I have never used, but I am under the impression its very alike with the E-Manage, correct me if im wrong). The little guys like the S-AFC and what not just arent up to this task. If you happen to be aware of the "S-AFC Hack", I dont even want to discuss putting that on a 350z.

A modern and worthwhile piggy back system can do a few things. It can modify airflow meter sensor voltage output to the ECU based on RPM. It can tap into the injector wires and extend the injector pulse width based on a correction table of RPM and MAP. It can also advance or retard your ignition timing with a RPM/MAP table.

THIS is prime. While it can be hard to get a nice flat fuel curve due to the stock ECU having SO many correction maps... you have everything you need.

Add fuel for boost? Easy, build yourself a table and do back to back tuning runs on the dyno or other means of wideband dataloging... starting rich and work your way to your ideal A/F ratio. This is great because you are just building your own correction factor. The stock ECU is already doing a great job of firing the injectors correctly... you are simply taking that signal to the injector and holding it open longer based on boost and RPM... the system is tapped into the injector wires after the ECU so the ECU has done its thing, your just adding a longer pulse when needed.

Retard ignition timing for boost? Easy, same as above... just start with a easy table of retard per PSI, then after your fuel curve is ideal on the wideband, tune your timing based on EGTs. Since your stock ECU is in there it is already got an AWESOME ignition map and tons of great correction factors... you are simply adding a boost correction table since the stock ECU is running too much timing for boost.

Need a larger injectors? ehh... you can do it but thats where it starts to get a little bumpy... and the larger you go the bumpier it gets. A small increase is no problem. Heres what goes on... if you put in a larger injectors you need the ECU to not fire the injectors as long as it does. The only way to make it fire shorter is to make the ECU think it needs less fuel. Only one way... take the airflow meter signal and drop it by a percentage. This sounds all good but it causes one little problem. Your stock ECUs main ignition table map is based on RPM vs Airflow. By dropping that airflow signal you are now putting your on a different place in the airflow map... A place that says to add even more timing. So now you need to factor this into your ignition correction map. Not so great big of a deal, but the more do hacks like this your are gonna screw with the fact that stock timing maps on new cars are super awesome and your putting yourself on the wrong part of the map. Remember if you only need to correct for the boost, your not too bad off.

Your car will still pass the SMOG test that inspects for trouble codes.

Piggy Back Cons: With a system such as or alike to the E-Manage your hard pressed to find a Con... other than that whole injector thing. If your building a RACE CAR get a standalone EMS.
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Standalone Pros
Theres only 1, complete control of everything all the time. What else could you ask for.

phunk

iTrader: (21)

Standalone Cons

1: Face it, the car will never, ever, run as clean as it did on the stock ECU. Your stock ECU was developed by a team of some of the best tuners in the world with over 30 years of R&D of engine tunine behind it. With a EMS... you are starting from SCRATCH. Most modern standalones will offer you with all the correction factors that a stock ECU has... but you still have to set them all yourself. The car will run perfect at WOT... but even a finely tuned EMS will typically have trouble starting, specifically in cold weather... it generally takes a few cranks to start even on the best of days. Sometimes it wont start at all and you gotta figure out where your wiring went bad or what start correction factor you screwed up.

2: When you go to SMOG and they plug in the OBD scanner... your standalone wont have much to say to that scanner. Now your car either gets denied or it hits the rollers... good luck. If your hardcore you keep the stock ECU in the car, pull a lot of tricks out of your *** and make that ECU think that it is still running the engine... then you will pass this smog test. Its been done plenty of times but it can take some R&D.

3: Unless you get a plug and pray like the AEM EMS, be prepared for the wiring experience of a lifetime. Not to mention in many applications you will need to fabricate a custom crank trigger setup.

4: Its not uncommon to loose use of some of the factory gauges as they process signal from the stock ECU that some EMS' cannot duplicate. Bust out the autometer MONSTER TACH! Or do some custom electronics to convert the signal, or keep the stock ECU in there for a tag team setup... or hope that your car isnt one of those with a jacked up instument cluster.

Ehh thats all thats been floating around in my head in the last 2-3 hours of processing thoughts on puting twins on my Z. At one point in time I was going to build my own system for it, and then market it. Then I realized that anyone would be really hard pressed to beat the Greddy kit when its comes out. So I am waiting for my Greddy kit, and when it gets here I will make a few improvement to it while installing it... and possibly market my improvements.

-Charles

KONVERTER

iTrader: (2)

Post of the month!

keiffer953

Very enlightening post, Good info, It;s just going to take me a while to absorb all of it, But I'll come back every now and then to read alittle at a time. Great Post though..

KONVERTER

iTrader: (2)

I read the whole thing...

Just confirms that if i do decide to go FI im going to go TT

fanatic

Very good post........I called Greddy on Friday (3days ago) and I was trying to get a "release date" for their TT. They said they didn't know yet.......should be in the next few months.........if anyone hears anything, I'm sure they'll post it. CAN'T WAIT UNTIL ITS AVAILABLE!!!

etx

Great post, a agree with everything. Exept the voltage clamp on a map sensor. In most cases its best to use a check valve on the map sensor, it works a lot better and will protect your map sensor from the boost. If (i should say when) i go FI I will most likely be controling a 2nd set of injectors via something like the emanage or the megasquirt. I am running a system like this on my other car and it works flawlessly. Rising rate fprs are hard to tune and work on a curve, I would rather tune a dynamic matrix.

azrael

SC vs TT, I agree 100%

I still want a standalone ECU though. I'd really like to see an AEM EMS application for our engine. Running an EMS with a wideband O2 and conservatively tuned timing would be a nice setup. I would keep it parallel with the stock ECU and hopefully trick it into thinking it's still running the car. There are a lot of functions in the stock ECU that would be impossible to replace.. like the LCD gauge, drive-by-wire throttle, and immobilizer.

Eventually AEM will come up with a solution, I'm sure. I have plenty of time to wait until then, I'm in no hurry to slap on the first kit that comes out.

I'm sure GReddy's setup will be nice, but like you said.. using bigger injectors is tough. With a high-power setup, bigger injectors is a requirement, not an option. Perhaps the solution is just a second set of injectors. Can the eManage handle that?

We'll see how it all pans out. Good luck with your setup.

Fëanor

"A twin turbo Z, and a supercharged Z, both with 400rwhp... guess which one is getting better gas mileage, will last longer, and putting less load on the engine to produce those #'s.... your right.. the twin turbo car wins."


Excellent theory. Unfortunately the numbers posted in this forum don't support your position. Most of the ATI dyno numbers posted here, when altitude and ambient temperature are taken into account, are very close to greddy's forecasted hp at the same PSI (370 @7psi vs 380 @ 7psi). This is also a good indication that the differences between engine stress is also negligible. Your point is purely academic under empirical observation.

You also dismiss the compexity problems of turbos too easily. C'mon man, look at all the install goofs among "reputable" mechanics just for the vastly simpler procharger? Just imagine what they'd have done with a turbo kit- a kit that's costs a whole lot more. It'll REALLY hurt when someone botches that Greddy job.

I know, I know. In an ideal world your car is tuned perfectly and all is bliss. Seriously, find me wherever the hell that is so I can move there. In an ideal world I'd love a turbo setup too, because the boost isn't directly dependent on engine RPM. Variability is always a good thing, but compexity trends toward errors.

kurt leonce

very good post, good information,

but the 1 18g turbo can make over 350whp

G3po

iTrader: (8)

Good post , you outta write a novel

Will Greddy , or will Greddy not seek CARB approval on this TT kit?
I keep hearing conflicting reports.

Z350Maniac

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But in all seriousness I completely agree with all that was written and even though it'll never be an option for me (I HATE being a college student with bills and just enough money for a car payment and insurance.) I'd get the TT over the ATI any day.

SlamMan

Good info for FI noobs. There is alwas somthing to be said for the "plug and play" ability of a SC kit though.

You said retarding ignition timing on boost would be easy. AFAIK Greddy never got their E-Manage ignition harnes to work with the Z's ECU. Did they get it to work?

I personally have to disagree with Mitsu turbos being releable. The following pic is a fairly common problem over at CSi with the Greddy turbo kits. Even with well cared for turbos. This isn't a pic of my car but mine looks just like it and I have taken good care of it. No reason it should look like this but it does.


FYI, the A in MAP sensor stands for absolute.

MacGuru

FI 101 This has helped me a lot in understanding the pros and cons of FI.

Thanks. -m

Fanman

Very nice post. Let's keep our fingers crossed that the price of the GReddy turbo will be about 20% off of MSRP. I think my post became a TT vs. SC post, when I originally wanted it to be "Can the TT setup justify it's $2600+ price difference to the ATI Procharger ? I will question you on your drivability advantage for turbos. I have been on the track with both types of cars, and I find SC cars easier to drive on the track. The power is much more linear. Like a bigger NA engine, where a few times I would get caught with the boost onset in corners with the TT car. Not fun.
Also nobody seemed to have answered my question on the other post, is the engine not the SC/TT setup the limiting factor of the car ? Does it matter that with the GReddy setup you can go to 550 hp if the engine blows up at around 425 hp. LIke I said before if you are intending to build up the engine and will be dropping $10K+ then the extra $3K for the turbo makes sense, but if the only power adders that will be on your car are the standard TT/SC kit, I/H/E, pulley, maybe an AFC then does the TT setup make financial sense. It is easy for most people to SAY the TT kit is better, and for them, but when time comes, are they willing to shell out another $3000 for it. That is a lot of money, let's hope there are substantial discounts for the TT Kit. Like I said if they had included the IC that would have made the $6000 much more rational.

alex30327

What ignition products will work with the Z? I have been looking at some MSD ingnitions that allow timing retard. Correct me if I'm wrong, but doesn't the Z have a DIS (distrbutorless ignition system). Also, if you install one of these will you have problems with your ECU or tachometer.

Basically, what is the best and easiest way to retard timing on the Z (from the drivers seat)?

phunk

iTrader: (21)

etx: yes your have a good point... using a check valve will actually protect your MAP sensor from damage if it is a sensitive unit that cannot handle the boost. also, yes the e-manage does have the ability to control sub injectors. i forgot to bring that up but for tuning purposes your right... it can be a great system.

azrael: again yes the sub injectors is a feature of the e-manage that i forgot to bring up. it would definatly come in handy when you wanted to go further. and you bring up an excellant point with the drive by wire... depending on how this is setup in the Z it could make things difficult and possibly even require you to put in a standard throttle body with a cable.

feaner: i guess i should have also said that the example situation was assuming matched compressor efficiency at the given boost level. however... one thing you might find interesting is that as you bring the boost up on the ATI kit and the Greddy TT kit, you will find that those 2 18g's will run into their efficiency range up higher and when you get to a point will be creating much more HP at the same boost... just guessing but say maybe around 18 psi. i would have to get all crazy with math and compressor maps to figure out where. as for complication with install... its my personal opinion that a TT, while much more time consuming, would actually be less complicated then a supercharger or maybe about the same level of complexity. i dunno... if the install goes wrong then your screwed either way and we can only hope this doesnt happen to anyone.

kurt leonce: absolutely! I personally havent taken one to that level... but the fact that it can support it is what i was trying to say. its exciting to get 2 of those in a kit like this. this is bigger than most the kits for the 300ZXTT.

g3po: personally i have no word one way or the other on CARB cert for this kit. would definatly be nice tho. however i would think that carb cert could take a long time and since their production kit isnt done yet... they dont have a kit to use for CARB testing... so my best guess is that when the kit is initally released it will not be carb exempt, and as time passes hopefully it will become as so.

SlamMan: I wish i could really answer that question. I was speaking on general terms with most of my word because I personally have not boosted a 350Z yet. Hopefully they have or get their ignition harness working with the 350. So what I say is general information that applies a lot of times and answers a lot of questions for those wondering...but it is by no means a guidelines for a manufacturer to use to produce or kit or anything like that, of course. Also, being that mitsu turbos are one of the most common turbos out there... it is likely to hear about and witness failure... however you picture provides very little evidence of a turbocharger failure due to the fact that the pool of oil there is before the compressor. The only way that oil got there is thru the PCV return on the intake after the filter. This can be indictive of a few things.... but not likely as a turbo failure.

Fanman: I guess I can not really argue with the driveability when it comes down to a bit of personal preference. Like I said I personally didnt like when a engine produced boost prematurely... but the consistency is definatly there with the Supercharger. However... I personally can adjust to the turbocharged car within a short period of time and when you get used to the car... you really can use the gas pedal as not only the accelerator but the boost regulator.

As for the limited factor being the engine and not the compressor... this is true. you can only take it as for as the engine can handle. Assuming all mechanics and enviromentals is identical... Engine A and Engine B will have the same potential output. However what my point was, that if one engine had the most efficient supercharger system, and the other had the most efficient turbocharger system... you would actually get to benefit from the engines output more with the turbo system... as a greater ammount of the power it has generated can be realized thru the crankshaft and drivetrain.

take everything you read with a grain of salt... even what i say... after all, who am i anyway.

phunk

iTrader: (21)

Alex: I really wish I could answer all your questions... but I have personally not yet started to play with all this stuff in my Z... I am just speaking of experiences with cars in general... and some or all of it may not apply to the 350z.

However... Distributorless ignition systems can just as well be worked with. If it definatly possible to use these devices in the 350z... it just may or maynot require additional measures. I cant imagine why the ECU or Tach in the 350 would ever know the difference.

As for adjusting from the drivers seat... i wouldnt expect to really get that feature... as long as you can get it right and leave it there. most modern advanced piggy backs require you to connect via laptop. The E-Manage can however be tuned with a E-01 boost controller if you wanted the fingertip in car tunability. This is assuming the E-Manage is compatable with the ignition system in the 350z.

SlamMan

This is what I thought at first too. A catch can was installed and the problem persisted. That means the oil could be coming from only one place as far as I can tell. I suppose with as many Mitsu turbos out there a few are going to fail but I have been suprised how many times I have seen this in the GReddy kits.