In-Depth Guide To Turboing Your NA Compression Motor:
In this guide I'll be talking about these key points:
-Engine health, and tests to do to make sure your engine is up to the task
-Can the Na motor really hold boost?
-Basic parts needed
-Power goals and parts recommendations to reach those goals
Before we get started, we need to check a few things to make sure that the motor you plan on boosting is healthy enough to withstand the increased power levels. Some easy things you can check before getting started with boosting your motor are oil pressure, spark plugs, and a compression test.
-Oil Pressure: (easily seen on the 300zx gauge cluster) at idle optimal oil pressure reading on the stock gauge is at the first tic or rather right around 30psi, under acceleration the oil pressure should rise to near or above the second tic or 60psi. If this holds true then your oil pump is functioning within the proper spectrum. If your oil pressure is low in both these scenarios I would recommend purchasing an aftermarket oil pressure gauge and testing this once again. The stock gauge for oil pressure has been known to be finicky and its possible your gauge is acting up. If your gauge reads low, DO NOT assume its acting up and boost your motor anyways. Your motor may be running just fine in Na form but with turbos you will need healthy oil pressure to keep everything lubricated and functioning properly. Even with a properly functioning gauge it isn't a bad idea to purchase an aftermarket gauge to ensure precise readings. If your oil pressure is low even after installing an aftermarket gauge, replacing your oil pump will need to be added to your budget. Na oil pumps will work just fine, but if you are replacing your oil pump you might as well get a tt oil pump. The tt pump will supply increased oil pressure since it was made for a turbo setup. Another thing to add is that the TT oil pump is cheaper then the Na one by around 15-20 bucks so why not.
-Check Your Spark Plugs: Spark plug condition can tell you a lot about an engines health and function, so it is imperative that you see just how healthy your motor truly is. Checking the spark plugs is an easy thing to do and goes hand in hand with the next topic of a compression check. Alright lets check our plugs. Pop your hood and grab these few tools: A set of pliers, Flat head screw driver, 12mm wrench or 12mm socket with a socket wrench, two 6" 5/8 extensions ( a 3' and a 6' will also work), and lastly a 16mm or a 5/8 spark plug socket will work as well. I like to start off by taking the balance tube off. There are two 12mm acorn nuts on the passenger side, one 12mm acorn nut and two 12mm bolts on the drivers side. You will also need to disconnect the vacuum hoses (use pliers gently to get them to twist then twist and pull them off), as well as disconnecting the S shaped hose that goes from the balance tube to the IACV ( depending on if you have replaced this before will depend on if you will use pliers to remove the spring hose clamp or use the screw driver to loosen the t-bolt clamp). There will be 3 o-rings under the balance tube make sure not to lose those. now un-plug each coil pack, remove the two 12mm bolts that secure each coil pack and lift the coil packs out. Next use your 16mm or 5/8 spark plug socket wrench attached to the two 5/8 extensions and remove each spark plug. Remember to place the spark plugs down in a way that you know which cylinder they were in, an easy way to keep track is to write 1, 3, 5 (passenger side of engine for LHD cars)) on the left side of a piece of paper and 2, 4, 6 (Drivers side of the engine for LHD cars)on the right side of the paper, then place the spark plugs on the paper according to the proper cyl number. Below are the most common readings for spark plugs, which can hint at the health of each individual cylinder.
What Spark Plug Readings Mean:
-Oil fouled plugs will have oil on them obviously. This can mean one of a few things, either oil is leaking from the valve covers down to the spark plugs, valve stem seals in the head are old, worn out and leaking, or oil is "blowing by" the piston rings and being burned in the combustion chamber.
-Fuel fouled plugs will smell like fuel. This can be contributed to one of two things. Either the fuel injector is out of spec and is pouring excess fuel into the cylinder, or the o rings for the fuel injector are worn out and allowing fuel to enter the cylinder by means of seeping past the fuel injector. Another possible contributor is your tune, if your tune is running really rich then your plugs can foul very quickly.
-Heat fouled plugs also known as Leaning out and can be identified as a completely white electrode tip, this is contributed to the cylinder not receiving proper fuel, or to the fact that the spark plug being used isnt a "cool" enough plug for engine.
-Ngk plugs are rated on a heat scale the lower the heat rating the less efficient the burn. If you are using a heat range 5 plug and your electrode tip is white from a lean condition, and your fuel injector is working within spec and receiving proper fuel pressure, step up to a heat range 6 or 7 plug)
-Carbon Deposits On Your Plugs can also be contributed to a "rich" condition meaning the cylinder is receiving too much fuel.
-Compression Checking Your Motor: This is a pretty easy test to do, I recommend doing this test right after taking the spark plugs out. Ideally you want your motor to be warmed up before doing this test. (Removing your spark plugs is detailed above). First you want to make sure that you arent going to be injecting fuel into the cylinders while you do this test, so make sure to disconnect the fuel injector plugs and pull out the fuse in the fuse box beside the battery that controls the fuel pump. Screw in the compression tester to where the spark plug would usually go then have a friend turn turn the key to the start position in the car for about 3 seconds. you want to pay attention to the first compression reading you see ( it will jump up to lets say 70 after the first rotation of the motor then rise to its final compression number). That first compression number and the final compression number are the most important. Do this for each individual cylinder and write down the L( Low/first compression number) and the H (High/last or final compression number) on a sheet of paper beside the cyl number ( once again the 1, 3, 5 pass side/ left side of the paper, and 2, 4, 6 driver/ right side of the paper for a v6)
Ideal/Healthy Compression numbers: A "perfect" compression ratio in any given cylinder is 180 or slightly higher(for an Na motor). But since most of us dont have a zero mileage motor, you really want to see above 160. Also you want to make sure that each cylinder is within 10psi compression difference. Here is an example. cly 1: 164, cyl 2: 157, cyl 3: 160, cyl 4: 159, cyl 5: 163, cyl 6: 161. The highest compression is 164 and the lowest in that example is 157, putting them within the 10psi difference range. If lets say cylinder 3 had 135 psi then it would be way out of spec and would need to be addressed before boost. if your compression ratio is within a 10ish psi range but lower on the spectrum around 140-150psi it can still be ok for boost but it is toward the lower end of the scale. If you are below 135psi i would recommend a rebuild or buying a new motor before boosting it.
Why did you tell us to remember the first compression number and the highest/ final number?
Simply because the "low" number and the "high" number can tell you more about your motor then you think. Normally you want the first compression stroke or the "low" number to be around 50% of the "high" number. Example: low number (75) high number (150). the low number can tell us a lot about the inner workings of our motor. if the low number is approximately 50% of our high number then our valves are sealing properly. IF however the first number is significantly lower then the "high" number (example low number: 40, high number: 137) then that signifies that our valves are not sealing properly in which case rebuilding your heads or buying new heads/ head will need to happen. If you need a compression tester ill link amazons best seller below.
Last Test Before Moving On:
Wet test: What this means is adding a tiny bit of oil to the cylinder (in through the spark plug opening, less than a water bottle cap), and then retesting compression. adding a little bit of oil can tell us if the piston rings are worn or not. each cyl with a wet test will put out slightly higher compression. However, if you have a cylinder that's low on compression that jumps up quite a bit in compression due to the wet test, that can mean that the piston rings are worn. Example: low number 70, high number 140, wet number: 210. a normal wet number increase is around 20-30psi.
Can The Na (10:5:1 Compression) Motor Really Hold Boost?
Why yes it can. It can hold a lot more power then most people think. Ill be going through a little bit of history here, and providing examples, and information to show you guys just how capable our vg30de motors are.
In the late 90's and early 2000's there were a few individuals that did turbo their na compression motors. Back then it was a well known "fact" that the na motors would "blow up at 350whp", or that the "na wrist pins would shatter at 7psi." but that simply is not the case. The reason people thought this was in part due to a few different reasons. The biggest reasons came down to fuel and tuning. lets start with fuel. The quality of fuel in the late 90's early 2000's was sub par to what we have now. A lesser quality fuel is more susceptible to detonation in a high compression forced induction scenario. What this means is that the fuel will start to combust before the compression stroke is finished within a cylinder aka "pre-detonation." Pre-detonation (also known as det) means that the explosion that is supposed to happen at the top of the compression stroke to force the piston down, happens before the piston reaches the top. This increased pressure is essentially forcing the piston back the opposite way then its supposed to go, which can cause massive amounts of heat, and can melt or crack pistons. The next subject is tuning. Most people who boosted their na motors back then tuned the motor exactly how they would a tt motor. The issue with this is that the na compression ratio is 10:5:1, where the tt compression ratio is 8:5:1. this is a HUGE compression difference. The best way to explain how big of a difference this is is by explaining how much more power is made with that na compression over the tt compression at the same psi level. A stock Twin turbo setup on a 8:5:1 comp motor at 12psi usually makes 320-330whp. The same stock turbo setup on a 10:5:1 comp motor at 12psi will make 400whp. Thats nearly an 80hp difference at the same psi level. What this all means is that if you tune a na compression 10:5:1 motor at 12psi like you would a tt 8:5:1 comp motor you would immediately run lean (meaning not enough fuel and increased heat and pre-detonation). That lack of fuel, that lean condition and that pre-detonation destroys motors( BOOM). Fast forward to 2016 our fuel quality and ability to tune high compression forced induction setups has improved by leaps and bounds. The z32 community now has more then a hundred stock internal na compression motors now boosted making anywhere from 300-783whp. We have dozens and dozens of 400-500whp stock internal na compression motors that have been making that power for 3-4 years thus far and still running strong.
A Few Dyno Graphs of Stock Internal Na Compression Motors w/ Forced Induction:
Choosing Your Fuel:
With high compression pistons like those in the Vg30de motor theres only so much hp that can be had on pump gas. The 10:5:1 compression in the na motors with 93 octane is only safe up to around 400whp give or take. Things such as intercooler size, piping size, turbo size, ambient temperature ect can all have an effect on how much power you can make on pump gas, but as stated below a good stopping poing is 400hp, above this mark its very easy to run into detonation which we do not want. The main pro of 93 octane is its readily available everywhere.
Fuel Octane Boosters:
There are fuel octane boosters such as boostane, lucas fuel octane booster and a few others that can raise your octane level from pump 93 up to around 100 octane. This boost in octane level will allow you to run more power on pump gas with a high compression twin turbo setup. That being said it can be costly after time since you will be having to spend an extra 10-15 bucks every fill up to put this additive into your fuel. But if this is the route you prefer heres an amazon link. :)
No this isnt the drug meth lol. Meth injection is a viable option to decrease chances of detonation. Snow performance meth kits will allow you to run higher power while staying on pump gas. but you will need to fill up the container every so often. if you are interested in meth injection for your z, the snow performance kit is linked directly below.
Ethanol (aka e85):
This is by far the best option in fuel to run on a high compression, forced induction setup. The benefits of ethanol are basically endless. A few of the key point (I will make a full guide to e85, and explain its uses in much more depth in a coming article), but a few key pros to e85 are as follows, drastically increases octane level, has a much more efficient and cooler burn in the combustion chamber, cools your engine, is very cheap compared to other race gases such as Q16, and because of these benefits allows you to run much higher boost levels, and increased timing to hugely raise your hp and tq output. The main con to e85 is that you will use approximately 30% more fuel, but for the power increase, safety and reliability it is completely worth that sacrifice.
Basic Parts Needed to Boost Your Stock Internal Na Compression Motor:
Here is a basic list of parts needed to Twin turbocharge the NA motor without buying a full twin turbo long block.
Bare minimum needed to do it right (leaving as much NA as possible):
-Stock Garrett TB02/22 turbos
-Jdm turbo quarter downpipes to mate stock NA exhaust (starting at cats) to turbos.
-OEM intercooler piping
-TT accordion pipes
-TT boost hoses
-Side mount intercoolers and Oem brackets
-TT a/c condenser
-A/c lines if keeping the A/C system
-Turbo oil and coolant lines
-TT oil pan
-TT oil tree
-TT oil cooler and lines
-TT fuel pump
-555cc injectors if you are staying on pump gas and low boost(under 400whp) or 740cc injectors if running on e85 ( 740cc injectors will allow for up to 600whp on e85)
-TT spark plugs NGK PFR6B-11B
-Boost gauge at a minimum. Although a boost controller is a fantastic idea: electronic is definitely a better choice, however, electronic boost controllers are more expensive. A manual boost controller will work but it will not have any safety features built in such as boost cut or warnings.
-Upgraded clutch (switching to a TT clutch and flywheel while still using the NA transmission is advised, This does require you to grind a small portion off of the inside of the NA bell housing and use a 3mm shim for the starter).
-Tuning: (the most important part) Ill talk about this a little bit more in depth. A custom tune is highly recommended, companies such as zhookup, z1motorsports, specialty z, zshack, racetech, and many others will be able to properly tune your high compression twin turbo or single turbo setup. A company that I would personally recommend for an EPROM chip base tune is Zshack, they have tuned dozens of na-tt setups and have made 581whp on stock twins which is a huge accomplishment considering the small size of the tbo2/22 turbos. DO NOT buy a stock tt EPROM and assume it's going to work on your high compression motor. I talked about this in the previous segment about "can the NA motor hold boost." a stock tt EPROM chip will allow you to turn your car on and idle but should never be used under boost, a proper tune, tuned for 10:5:1 compression and stock twins will need to be used.
This list can obviously be changed based on what performance parts you may want and there are important things that are recommended (like an AFR gauge) but that is up to your discretion and budget.
( The list above was written by Michael Doscher, and edited by Ocean Nickel).
Ok so how much should I plan on spending?
This does vary depending on if you buy parts used or new, but ill go through an average price for some of the parts needed and a total estimate at the end. Also some of the parts below are text linked, meaning if you click on them it will bring you to a place you can purchase the part for a good price. The rest of the parts are used parts meaning you will need to find them on z32 and 300zx for sale pages.
-Stock TT style manifolds (used) $50-120 $50-120
-Stock Garrett TB02/22 turbos (used) $250
-Exhaust gaskets $45
-OEM intercooler piping (used) $150
-Jdm turbo quarter downpipes $100
-or you can also get a decent downpipe and testpipe kit here for $290
-TT accordion pipes (used) $100
-TT a/c condenser (used) $95
-A/c lines if keeping the A/C system $200
-Turbo oil and coolant lines $130
-TT oil pan (used) $100
-TT oil tree (used) $95
-TT oil cooler (used) and (new) lines $180
-TT fuel pump (new) $298
-Walbro 255lp (if you are staying on 93) $85
-Walbro 450/485lb (if you are going e85) $145
-Injectors (pick one)
-Subaru STI 550cc (04-06) w/pigtails (used) $280
-Nismo 740cc injectors $765
-DW 740cc injectors $639
-TT spark plugs NGK PFR6B-11B $78
- Or NGK BKR7EIX (I recommend these) $50
-Boost gauge at the minimum. $78
-Clutch (tt clutch with stock tt flywheel) $550
For the list of parts and prices above we will be mostly picking used parts meaning that if you buy brand new parts the total will come out to more. I'll be going with the Subaru 550cc injectors, BKR7EIX spark plugs, Walbro 255 pump out of the above options (this is an example for a 93 octane stock tt setup on a NA compression motor). This parts list and pricing total below is for a 9psi 350whp roughly setup, for 400whp you will need at minimum a boost controller. I would also recommend larger Side mount intercoolers (smics), and a 2.5" exhaust.
Lets talk about some upgrades for a 500whp setup:
Replace the STI 550cc injectors with 740cc ones, 2.5 or 3' downpipes and exhaust, Walbro 485 fuel pump, larger smics, Selin dual intake and a tune on e85. That is how simple it is to make 500whp on a NA compression motor (10:5:1 compression). If you wanted to make 500whp on stock twins on a tt compression (8:5:1) compression, you would need manifolds, 2.5 ic piping, bde cam gears ash spec massives or z1 b.a smics as well as all the above-mentioned mods for the na-tt setups. and even with this, many would choose to upgrade turbos adding $1500+ to their build just to make 500whp on the lower compression tt motor.
600whp setup for Na compression
in addition to the parts listed above, you would need larger turbos. (581whp has been done with stock turbos with Na compression) but it will be easier to make that power with a larger turbo such as sport 525's 535's or 555's, and gt2560r which have incredibly fast spool up. And of course, you will need an upgraded clutch and a tune.
Boost gauge and Controller:
Many people buy a boost gauge and a boost controller which is perfectly fine, however, you will be spending more than just getting a boost controller gauge. Here is an example of the average purchase for a boost gauge and a controller as separate entities. Boost gauge: $78 and a Boost controller: $400, at this point you are at almost $500. I recommend going with the AEM Tru-Boost linked below. I have personally used a few AEM Tru-Boost gauge/ controllers and I really like the setup, plus you are saving well over $100 when you go this route.
If you plan to only stay on 93 octane and under 400whp I personally would recommend getting Subaru Sti 550cc yellow topside feed injectors from a 04-06 sti. They are well priced and drop straight into the 300zx new style fuel rail. They can also be used in an old style fuel rail with an adapter kit as linked below.If you plan to make above 400whp on your na-tt setup skip the Subaru injectors and get some 740cc injectors. Nismo 740cc injectors and DW 740cc injectors will both work well in this instance. The new design on the DeatschWerks injectors has hugely improved injector efficiency and reliability.
My personal preference as far as fuel pumps go is Walbro. I've used the 255lph fuel pumps in na-t, na-tt, twin turbo swaps, sr20det, vh45de setups. As well as a few 485lph fuel pumps in some of the higher hp builds, and they have lasted and performed flawlessly. For those of you staying on 93 octane and under 400whp, a Walbro 255lph pump will be plenty for your goals. For those of you that plan to make above that 400whp on e85. The Walbro 450lph/ 485 pump is what I would recommend. they can support mid 600whp worth of fuel on e85.
Wideband/ Afr Gauge:
No matter if you are running 7psi on stock twins of 20psi on GT2871r turbos a Wideband gauge is ALWAYS a good idea. AFR/ Wideband gauges give you pertinent engine information that can notify you of the current air to fuel ratio. Whats air to fuel ratio you ask. Well simply put its a ratio of how much air needed per amount of fuel. the higher the Afr (example 16:1) would be considered very lean, and the lower the ratio (example 10:3:1) is rich. Stoic ratio 14:7:1 is considered to be a good ratio for a clean burn and fuel efficiency on a Na however in a turbocharged vehicle we really want to be slightly rich since we will be producing more heat and power. Most tuners shoot for an afr around 11:8:1. on pump gas with boost. Below are 2 gauges I would recommend. The AEM gauge is great however it will only monitor 1 exhaust bank. the Innovate gauge will show you the afr for both sides of the motor.
If you plan to do an intake upgrade get a Selin Dual Translator. It is hands down the best dual intake option for the 300zx. Even if you are only staying Na I've seen up to 12whp increase with the Selin dual intake kit with a tune on a Na motor. You should also upgrade your "boost hoses," as the stock rubber ones crack after time.
Intercoolers and Ic Piping:
The best 2 smic kits and 2.5 ic piping kits on the market right now are the Z1 B.A Smics and 2.5ic piping kit. and the Ashspec Massives (smics) and 2.5 piping kit. This is an investment to look into if you are wanting to make 500 or more hp, and would still greatly benefit you at lower horsepower levels, by increasing spool up, decreasing IAT's (intake air temps) which directly improves the amount of power you can make. But if you are on a budget these godspeeds work just fine.
If you are boosting your Na motor. The best route, in my opinion, is to get an oem tt flywheel and a clutch that will support your power goals. another thing to consider is clutch feel. what do I mean by this? well, there are a few main different types of clutched that are used on a regular basis. If you want an Oem clutch feel stick with an organic clutch disk. However organic clutches usually can't hold as much power as a pucked clutch. there are multiple different styles of pucked clutches, 3 puck, 4 puck, 5 puck, and 6 puck clutches. A clutch with a puck design will usually grab harder, and quicker than an organic disk. Pucked clutches also usually have a harder pedal feel. So it's up to your personal preference to choose the style of clutch that fits you and your hp goals. Two Clutch options that I do not carry but that I have used and would recommend. are the RPS High Five clutch, and the Southbend clutches, both will hold incredible power, they are reliable and high-quality pieces.
I have personally used Mishimoto TT radiators in a lot of setups. They work great, fit well, and cool the engine appropriately. With the Mishimoto TT radiator, my engine temps would sit at around 187 degrees Fahrenheit on a 100-degree day in Georgia traffic. So this is definitely my first recommendation.
For your Na-tt setup, I highly recommend the use of NGK BKR7EIX spark plugs. I use them in all of my single turbo and twin turbo high compression setups, and I will always recommend them to others. They are a "heat range" 7 plug meaning that they burn "cooler". On top of this, they come pre-gapped at .31 which is a smaller gap than stock tt plugs. This smaller gap coupled with a higher heat range of 7, basically means you will have a very clean, efficient burn and a much smaller chance of spark blow out at higher psi levels.
The highest quality best performing twin turbo manifolds are hands down the Ash-Spec manifolds. They outperform all other cast manifolds on the market. The next highest quality is the MSP manifolds. Most of the guys wanting to do an NA-TT setup, however, are going to stick with stock manifolds. They are by far the cheapest and most direct way of completing your tt setup on the Na compression motor.
Downpipes and Exhaust:
Downpipes and Exhaust brand comes down to personal preference. The main thing to take into account is the piping diameter. a good 2.5-3" downpipe & exhaust combo is essential for optimal flow and performance. Obviously, the 3" will outperform the 2.5" option and will allow you to achieve higher Hp levels. But for most of us, a 2.5 system will be just fine.
TUNING ( THE MOST IMPORTANT PART):
You can have the best parts in the world but if your tune is crap you'll be throwing a lot of money down the drain. Ideally, a custom tune is the way to go. Getting your car tuned on a dyno at Z1motorsports, Zhookup, Zshack, Specialtyz ect is a very good option. All of these companies will be able to tune your z appropriately. If you don't have a z specialty shop near you visit Zshack's facebook page. Scott Taylor and Rick Norman are the owners of Zshack. They have been at the front of the pack as far as EPROM chip tuning goes for high compression twin turbo 300zx. They now offer Eprom based tunes for your na-tt setup. Normally their EPROM chips cost $100, and you get to specify what turbos, compression ratio, manual or automatic, and the type of fuel you want to use. However, If you contact them and use Z32NA-T as a coupon code they will give you a $15 dollar discount on their EPROM chips bringing the price to $65. Zshack is the ONLY company i would personally use for a eprom tune for a na compression twin turbo setup, not to mention Scott and Rick are both very knowledgeable, down to earth, cool guys that will tell you how it is.