Turbocharging the B15 Sentra

Turbocharging the B15 Sentra (SR20DE+T)

By: nametakennow

There are a number of ways to go about this, including engine swaps, aftermarket kits, and piece-together rigs.

I went with the last of that set.

Before:

After:

One of the most infuriating portions of my turbo quest has been figuring out what parts I need/have. Thus, as an addition to my NA->Turbo SR DIY, I figure a more organized parts list would be a good idea.

So, this is that list, divided into sections. I’m listing what is absolutely necessary to make the car run and be drivable, then the recommended list is to make it perform to its full potential.

Intake:
Filter – Any will do. Remember, this air is going through your turbo into your engine, keep that in mind.

MAF – Stock works unless you’re running lots of boost, then a Z32 MAF is a good bet.

Intake tube – This should include a recirc point for the BOV and a line for the valve cover breather.

Turbo – Your choice, bigger turbos mean more air, which means more fuel and possibly more management work. For those of you running off of Nissan Parts Bin kits, keep in mind that Bluebird and Avenir T25s are different, with Avenirs having ball-bearings and a higher wastegate actuator setting stock (9psi instead of 7).

Turbo out pipe – Personally, I like how mine comes down off the turbo and towards the passenger side for my routing. I was even able to keep the AC so as to keep the ladies happy. However, I see lots of setups where it comes up and over the exhaust manifold, then down and around the front. Your choice.

Intercooler piping – Your size should match your turbo/boost level. For low boost applications, 2.25in will keep boost response up and leave a little room for more, but for those of you who like big turbos, invest in bigger piping. I run 2.5in for a 10psi T25 and get great response, for reference. There are piping kits available. Another option is to buy some stainless steel or aluminum exhaust piping with several 90* bends, a 45* or a few if needed, and some straight pipe.

Intercooler – This should also match your turbo. Try to match the in/out size to the IC piping you’re running. Get a core that matches your hp goals. Most are advertised with the power they can support. Also keep in mind that huge ICs can cause pressure drop and cover up your radiator, increasing engine temps. FMICs are a good bet, but TMICs are more stealthy, though prone to heatsoak. A sidemount would be tough to fit.

BOV – Get whatever you want. If you get a Nissan one with your setup, you might as well keep it. It’s noisy enough to give you a smirk on shifts, but quiet enough to keep the sleeper effect somewhat plausible (as if an intercooler grinning under the bumper doesn’t advertise what’s up …). This is all a matter of personal taste, they all work the same. RECIRCULATE, please.

Misc. – Various hoses and silicon connectors for the pipes and tubes you need. A recirc line, IACV line, wastegate line, vc breather line (Get an oil catch can!), and that funny other line to the bottom of the intake mani near the TB for you B13/14 SR people. Sizes vary, measure your inputs/outputs and get however many feet you need.

Exhaust:
Manifold – Whatever comes with your setup. Make sure it matches your turbo, the output to T25/T28/etc is different than T3/T4/etc turbos.

Wastegate – Your call. If your turbo comes with one, use it, but if you want bigger, get a bigger one.

Downpipe – If your setup comes with a turndown off the turbo, use it unless you want more room. Everything should be at least 2.5in, preferably 3 if you’re running much boost. Make sure to have two O2 bungs, one for your 1st O2 and the other for a wideband so you can tune. Backpressure is bad.

Catback – This should match the size of the downpipe. Bigger is pointless, smaller is stupid. Get one that flows well with straight through cores, that sort of thing. Keep in mind that this thing will be LOUD, so a resonator is recommended both for volume and tone. Without resonators, most cars sound tinny and ricetastic, and Sentras/NXs/whatever are no exceptions. Your resonator should be straight-through as well for best flow. I’ll go ahead and say that my BRM Exhaust from our beloved owner Greg sounds great and flows well. Backpressure is bad. OBDII folks, keep in mind that you need to move your 2nd O2 bung behind the cat to stay legal.

To make this clear, BACKPRESSURE IS BAD FOR TURBOS.

Fuel/Management:
Injectors – Get injectors to match your boost level. Below 12psi, 370ccs will work. 34lb (360cc) MSDs are a good choice for top-feed people (B15), 370s from any other SR do nicely for side-feed people (B13/14). For higher boost, 50lb MSDs (B15) do nicely. Most B13/14 people get a top-feed fuel rail when they get to needing more than 370s. I believe JWT can help you out, or whatever source you may be able to find. I’ve heard of people making their own.

Computer – A piggyback like an SAFCII does the trick. Check the recommended list about this.

Wastegate control – If you’re using a wastegate actuator that came with your turbo, just hook up the line and go. Those of you with boost controllers, read the instruction manual and bear in mind that more boost requires more fuel and management, as well as increases the wear and tear on your engine components. B15 guys, bear in mind that roller-rocker SRs do not have quite as strong of pistons/rods and have more of a tendency to shoot rocker arms at high rpms.

Misc.: Besides the aforementioned hoses, you will need…
Oil – An oil feed line of whatever size matches your turbo outlet and the hole you’ve tapped on the block. A multiport T off the sending unit is another must so you can feed the turbo. SPL has one with two ports, one for the engine, another for the turbo. Nissport and Tuner Toys make them with more ports.

Coolant – Lines for coolant, some rubber fuel hose from NAPA is cheap and easy.

Fittings – This is probably the biggest pain I ran into. If you have an aircraft supply shop nearby, you’re in luck. ATPturbo.com has basically every fitting you need. It’s kind of confusing still. With the T25, the oil inlet is -3AN. Ask people who have whatever turbo you have what fittings you need and be prepared to order/go hunting for these.

Injector connectors – If you’re running MSDs bear in mind that they have a different plug on them that you’ll need to solder into your wiring harness.. Autozone has the part, it’s a GP Sorenson, part # 800-9213. Each Autozone will have one, at best, so be prepared to run around a bit or have them transfer them in from other stores. You need 4, one for each injector.

And now, the recommended list…

Highly Recommended:
Boost gauge – My VDO was something like $30, then I got a mounting cup for it. Works well, easily visible. I need to wire it up so I can see it at night. You’ll need another hose for this, run it through the firewall on the passenger side near the glovebox, there’s a grommet there you can pull out. Keep in mind that where it taps into determines whether you get vacuum or not. I suggest tapping in near the TB for the most useful measurement. Using a QuickTap from ATP will make this easy, as it just slids into one of your IC connectors. Your call.

Fuel pump – A Walbro 255lph is a good call. B13/14 guys have specific part #s, but there is no listing for B15s. B15 guys, either use a B14 pump (apparently it fits rather easily, I’m trying to dig up the install info for when I do this myself) or the in-line kit, PTI has both. Without this part you’ll more than likely get an A/F spike at about 5200rpm (max power, oddly enough) to 12.5 no matter what you do with the SAFC, though it falls back to 11.5:1 (what we want) by 6000rpm and stays steady to redline. Mine spikes to 12.9 on occasion and that causes some detonation with the stock pump. Point being, if you can’t afford/find a pump right now, either don’t do the install or don’t wind it out. Trust me, there’s plenty of fun to be had in 3rd and 4th gear on winding backroads at 3000-4500rpm.

FPR – NISMO is a good choice, but they’re not cheap. Your call. You’ll need this to get the pressure right with that big pump, otherwise you’ll run stupid rich.

Moderately Recommended:
Management – B15 guys, look into getting a JWT-tuned B14 ECU and rewiring to run it, B15 SR ECUs cannot be tuned. B13/14 guys, look into getting your ECU tuned by JWT. This way, the piggyback is just for fine tuning, rather than for the livelihood of the engine. Be careful with your ECU or it might decide it hates you and randomly malfunction (don’t ask me how I know).

Suspension: A good shock/spring combo is definitely a good idea to keep you on the road with the new power. I like my Koni Yellow/Eibach Sportline combo. Coilovers would be even better. I hear good things about JICs (especially the FLTA2s) and TEINs, and lots of arguments about K-Sports. Many guys swear by Yellows and Ground Controls, claiming better handling than the coilover boys.

Wheels/Tires – Wheels should suit your style and budget, but more importantly, they should have space for the rubber you need to keep that power going to the ground. For B13/14 guys, you don’t have as much room in the fenderwells, so a 15X7 or 16X7 would be great, though it may rub a little depending on your suspension. B15 guys get their one and only break here. With my Koni/Eibach setup, a drop of 1.5in and with not a whole lot of wheel travel, I easily fit 17X7s with 215/45/17s. NISMO wheels are 17X7.5, which would give you the option of a 225 series tire, though this will be close to rubbing, depending on suspension. As tires go, the stickier the better. Azenis are a good bet, but if you want to drive this thing year round and as a daily, and are budget conscious, I have to recommend some Falken Ziex Ze 512s. They handle my power for the most part (though wet+turning+WOT and we’re off to crazy wheelspin land, even with the LSD), and RED_DET, our mod here, runs them around his 15″s on his B13 with 278whp with no complaints, wow. $74/tire for 215/45/17s and even cheaper for smaller sizes.

LSD – A limited slip is your new friend. Get one if you didn’t have one stock.

Brakes – Please get some better stopping power. If nothing else, get some Hawk HPS pads. This isn’t really necessary, but, like suspension, you need some way of keeping control with the added power. I went for a pretty strong route with Brembo slotted rotors, Hawk HPS pads, and Technafit SS lines all around. I also run ATE Super Blue fluid. Speedbleeders will make this install easier. As I said though, some good pads will do the trick, make sure to bed them properly.

Transmission – B15 guys, you’re in luck. B15s have the strongest trannies of USDM Sentras. P11 G20s share this transmission. B13/14 guys don’t have this, but the stock transmission will hold quite a lot of power (RED is on the stock one with, as mentioned, 278whp). If your tranny is on the way out, look into getting a B15 or JDM one. However, everyone should look for a new clutch. My stock clutch is holding pretty well, but I don’t think it’ll last long. Look at the advertised power levels and get what suits your setup.

Other:
Lots of guys swear by the virtues of EGT gauges, being it that EGT is often a good measure of what’s going on with combustion. Other gauges to look at would be Oil Temp and Oil Pressure, a better Water Temp gauge, Tranny Temp, and A/F Ratio.

A shortshifter wouldn’t be a bad idea either, mostly because they’re just that much fun.

Good fluids like Redline synthetic tranny oil, Redline Water Wetter, and Mobil1 Synthetic engine oil are always a good idea.

Those of you with G20s, things I mention for B15s also apply to P11 G20s (2000+) while B13/14 notes apply to P10 (before 2000) G’s. This includes engine and transmission issues. Suspensions are different.

Parts Used For THIS Install:
Nissan Avenir exhaust manifold, ball-bearing T25 turbo, intake pipe, and BOV (or the same stuff from a Bluebird or GTi-R)
MSD 34lb/hr (360.4cc/min) fuel injectors top-feed, low impedance (or larger if upping boost past 12 or so PSI or using a bigger turbo)
JohnnyRaceCar 2.25in inlet/outlet front-mount intercooler
Intercooler piping (some stainless steel bends from an exhaust shop will do)
High temp silicon couplers for ic piping, including transitions up to the TB, BOV, and down to the turbo outpipe, if needed
Apexi SAFCII or AEM EMS or JWT-tuned B14 Sentra ECU
40in oil feed line, -3an with a 90* end on one end
7in oil return line (be safe and go with an 8, but don’t go bigger than a 10, I have a small leak because my 7 is not compressing right – now that I think about it, a 6 may do as well, if you’ve got lots of cash, get several size and see what fits you well)
tap for oil return on the block
oil sending tee (SPL has lowest price I’ve ever found)
new banjos and stuff for the turbo, check ATPturbo.com for all this kind little stuff
oil catch can or a breather filter if you’re going to ignore this or buy a can later
1in ID hose (get 2ft and cut excess) for BOV recirc
1/4in ID hose for line to wastegate actuator (get 3ft, cut excess)
1/4in ID hose for line from BOV to TB (2ft or so, cut excess)
1/4in ID hose for coolant feed/return (get 6ft, cut excess)
1/2in hose cap for un-used BOV opening (more explanation later)
turbo tap or quicktap for boost gauge feed
1/4in hose for boost gauge
boost gauge
GP Sorensen injector connectors (Autozone part# 800-9213, each store will have one, be prepared to drive around or wait a day or two to have them sent to your local store – supposedly Advance has them too, though mine didn’t)
Exhaust piping and a flexpipe for your downpipe, use 2.5in ID pipe at least, 3in ID for high boost apps
Flanges for downpipe (JWT has the ones you need, except the 2 bolt cat flange, check an exhaust shop for this)
FSM, clamps, plugs, nuts, bolts, sealants, electrical tape, solder, patience

Overall cost? Probably in the $2000-2500 range, plus countless hours soaked in God-knows-what and smelling like some cross between motor oil, rotting fish, and general death. I probably forgot some little stuff, you’d best have another car handy for runs to Autozone.

Think you’re ready?

Sad to say, I bet you’re not, but hopefully this write-up will alleviate the pain a little.

Prep:
Install SAFC:
Disconnect the battery.

There’s a box in the passenger corner of the engine bay right by the firewall. Remove it. Now, open it to find the ECU. Take the white clip thing off and push the black lever back from where it was to separate the wiring from the ECU.

Now, find the right pins, solder the SAFC wires in.
32 is rpm signal, 35 can be used as well, using 32 you won’t be able to correct past 6000rpm – EDIT: Use pin 75, this signal avoids the lack of correction past 6000rpm while avoiding the summer overheating that can be caused by using pin 35
48 is ground
61 is MAF signal
110 is power
81 is knock
92 for throttle, 71 works too, but 92 gives you the flexibility of modifying this signal if you need to

The wires in the ecu should be uncut if at all possible. you can use the soldering iron tip to melt the isulation off. the only one that is hard to do is the clear one (forgot which one that is), it is heat resistant tubing. For solder, use somthing with silver in it, or a standard 40/60.I would not reccomend the lead free stuff because it is hard to work with at times and can be weaker.

The MAF wire has to be cut because it is routed through the SAFC.

If you have it available, you can use heat shrink tubing. it creates a better insulation, but can be risky because you have to heat it up to make it contract and cover the solder joint, and the wires have VERY little slack to work with so you run the risk of melting adjacent insulation (bad thing).In general, be cautious.

Perform the SAFC setup routine.

Take Stuff Off:
Remove the bumper, there’s several bolts, including some stuffed into the corner behind the bumper and between it and the fenderwell lining. It’s a beast, I have no idea how my buddy got to it, consult the FSM.
Remove the passenger-side plastic cover that runs around the corner of the bumper support and back towards the wheel. You’ll have to cut it into two pieces and remove the part that covers the coolant reservoir, your IC piping doesn’t want to play nice.
Go ahead and remove the foglamps, if you have them. Remove the screw on the top and just push from the back and they’ll pop right out.

Now, if the car isn’t in the air, go ahead and do that, the higher the better, and preferably all of it.

Remove the exhaust midpipe, start at one end and work to the other. There are several heatshields, but the bolts are easy to find.

Remove the stock intake system. It has a few brackets. If you had a CAI before, remove it and clean the filter if you plan on reusing that.

Remove the exhaust manifold. There are 4 each nuts on top and bottom, you’ll have to get some creative sockets set up, a rotating/bending socket attachment will be helpful here and later on.

Remove the passenger front wheel. You have to, don’t gripe.

Drill and tap for oil return:
This has been done a lot. It’s the exact same as on any other Sentra. I’m not going to get all crazy about it, Google it or email me for more specific questions. Get a friend or two to help you if you haven’t already. – pretty good article here -> http://htttp://www.brazosport…..html
Now, support the engine by placing a tranny jack (or use a normal jack with a block of wood on it) underneath it, there’s a rectangular area that does the trick.
Now, jack that jack once or twice so that it’s holding the weight.

Remove the front-rear engine mount beam (or at least one side of it). There are 4 monster bolts (17mm, if I remember correctly) that hold that thing on, they all have rubber washers. A big socket wrench, maybe a torque wrench, would be nice. Pop these off.
Now, there are some bolts that come to a point at one end that run through the mount and bracket. Remove these.

Voila, the beam will come right down. Then engine will stay up on the two lateral mounts, but the jack is a good safety measure.

Now, remove the lower (steel, black) oil pan. I hope you drained the oil first.

Remove the oil pickup.
Remove the upper (silver) oil pan. Watch out for these bolts, they’re hard to get to, a small socket did the trick for us…

Now, drill and tap. Check the link earlier for specifics on this one. You pretty much just have to go for it.

Get a friend to help you and you can drill from the back (right under your crank with oil dripping on you, yay!) I drilled from the back, my hole ended up a little to the right/bottom, but it works.

Clean off the old RTV from the pans, put some new stuff on, and put it all back together, make sure not to overtighten the oil pan bolts, you’ll crack it, don’t ask me how I know.

Install banjos and stuff:
Oil return/oil feed
Coolant return/coolant feed
Pretty straightforward, it’s tricky to get in the hole for oil feed, make sure to have gaskets/copper washers, they should come with the kit (assuming you get the ATP turbo setup)… make sure your outlets match what you’re using for lines. Specifically get barbed coolant banjos.

Install coolant feed/return lines:
The throttle body has some coolant lines for warming it in extreme cold. I don’t plan on living anywhere cold, I hate cold weather unless I’m skiing. That said, I just removed these lines and ran some hose to the turbo from here.

Remove the throttle body (4 simple bolts), clean it with carb cleaner while it’s out.
Find the lines, disconnect the old hoses, put the new hoses where the feed/return was. Don’t worry which is which, coolant can flow either way in Garrett turbos.
Plug the barbs you just removed the lines from on the intake manifold, anything will work, there’s no pressure.

Reinstall the TB, the gasket should still be good.

Trim the tube thing:
There’s a stupid tube that will try to prevent you from dropping in the mani in the next step. There’s a rubber hose that runs from near the mani area to the valve cover. The lower hard pipe is what we’re talking about. Trim it back to where before it bends, reflare it if you feel such an urge. Mr. Dremel is your friend.

Install exhaust manifold/turbo/turbo turndown:
Make sure the turbo heatshield is on, you can’t get it on later. You may want to go ahead and extend the O2 sensor wires 3-4 inches now to save you the trouble later, as the Avenir O2 sensor plug doesn’t reach the wiring harness plug.

Remove the EGR tube that screwed into the old manifold, the new one doesn’t have it. You’ll have to re-route this later to pass emissions.

By the way, I’m assuming you’re keeping your AC. I’d have removed mine except the ladies would complain, and we all know an unhappy lady makes car rides not fun no matter what you’ve got under the hood. So much innuendo…

Work it down in there. There’s a rogue AC line that will try to stop you, show it who’s boss. You’ll probably beat the stew out of your radiator fan shrouds, sorry. It’s a tight fit. Trim the wastegate actuator bracket as necessary.

Connect oil/coolant lines to turbo. Also, connect the oil feed line to the oil sending unit, which is right near the oil filter. It’s pretty easy to spot. Screw your sending T into it and connect the stock line and the turbo line.
Bolt it in as per the FSM. Need an FSM?  Go to Nissan Service Manuals.

Hard part’s over, right? Ha. You’re not done, but at least you don’t have to cut stuff… or do you?

Intercooler piping:
You’ll need several cuts and connectors for this. I’d suggest you run it out toward the passenger side from the turbo, around the bumper support jackstand point, around the front to the intercooler (comes with instructions on mounting), around the other bumper jackstand point up through the hole where your stock intake resonator was, then up right by the strut tower and over to the TB. Make sure to run the BOV the right way, fat side away from the intake mani.

You’ll need a hole somewhere after the intercooler for the intake temp sensor. Make sure to have a grommet to get a good seal.

Run the 1/4in line back to the TB area from the top of the BOV. Run the same-size line from the small side outlet down to the wastegate actuator.

Cap the one labled “WTF?” B15/P11 SRs don’t have a line running to the bottom of the intake mani just after the TB for idling purposes. Yay.

Install pre-turbo intake tube
The Avenir intake tube goes up toward your battery, turns back then again towards the driver’s side. Trim it before it turns to the right the last time somewhere to put the filter near the brake fluid reservoir. Make sure to plug the MAF back in. Refer to the general engine bay pic. To see this and the BOV routing, as well as where I put my intake temp sensor –

Install Fuel Injectors:
Follow the FSM procedures for the most part.
Pop off the accelerator cables
Pop off the brackets.
Undo your fuel fill cap, otherwise you’re going to leak a lot of fuel. You’ll still leak a little bit, oh well.

Now you can get to the fuel rail. Remove the bolts. Raise the whole assembly out of the block, undo the injector clips to the rail and electrical pigtails and pull them out of the rail.

The MSDs are bigger and their electrical connectors are differently shaped. Splice the GP Sorensen connectors into your wiring harness. Get some longer bolts to attach the rail to the original points. Get spacers (can get them at Nissan) to cover the gap, 3-4 spacers per bolt will do.

There’s a hose that runs from the valve cover to a hardline behind the fuel rail. Remove it. Now, trim the nipple on the fuel rail about half its length. Don’t worry about any adverse effects or reflaring, the vacuum pulls the hose on harder in this spot.

You’ll need some new injector clips to clip them onto the fuel rail. Autozone sells some, GP Sorensen to the rescue again.

Put some oil on the o-rings of the injectors, slide them into the rail, then slide this assembly into the block.

Bolt it in. You may have to unbolt and move that rear bracket out of the way to get to the bolts. It’s a pain, a huge one.

Plug in your new injectors electrically. EDIT: If you use low impedance (2 ohm) injectors as in this example you’ll need a 10 ohm resistor in the wire going into each injector. It turns out that B15/P11 injectors (not sure about B13 and 14 and P10s) are high impedance (12 ohms). Going without the resistor the car will run incurably rich because the injectors will essentially be stuck open every time they fire.
RE-EDIT, FINAL SOLUTION: I got some bunko info on the injectors needing to be high imp., they should be low, so the MSD bolt right in and don’t need resistors, just different clips. Trust me, my car ran like crap with the resistors in. So, to be clear NO RESISTORS!

Refill with oil and coolant, replace the bumper and such (you may want to wait til you’ve checked for leaks), reconnect the battery and check the fuel system for pressurization by turning the key to the on position. Take this chance to program a good 12-15% low throttle fuel curve all around so that you can get it to a shop for dyno tuning. Drive VERY wimpishly til you get it tuned or you will blow your motor, do not use any more throttle than you have to. Absolutely do not go into high rpm or high throttle, keep it at 2000rpm or less as much as possible, to be safe. If you don’t have any leaks, you’re ready to start it up.

http://q45.spilky.com/gallery/…I.AVI
That’s before I had the downpipe made. Purs like an angry kitten/lawnmower and kills small woodland creatures with unclean exhaust fumes. My basement smells like spent fuel still… I probably do too.

Fix any leaks you might have, change the oil and filter again after having run it that first time for 5 minutes or so, just to make sure any metal shavings from the drilling got trapped and can’t come loose later.

Get it tuned, get a downpipe made, have fun.

I’ll add more if I happen to think of it, but I’m pretty sure that’s it. It’s really a matter of diving in and going at it, but I think this will serve as a good reference. An FSM is pretty much a necessity, use the link provided. I’d be happy to answer any questions- nametakennow@hotmail.com