BDC's Wife's Turbo '03 Altima Build for 2011

[BDC Motorsports]

Howdy folks, my name is Brian . I'm new to the forum (first post) and I'm based out of the Dallas/Ft. Worth area and am primarily a Mazda rotary engine guy although I'm also skilled in porting as well as a few different EFI systems. Several weeks ago I was eyeballing my wife's engine bay in her '03 Altima. I've already been in it a little bit and have done a few things (removed part of the factory intake ducting; plan on installing a MAF adapter and sticking a 3" filter in front of the MAF itself, ported and polished the throttle body, bypassed the throttle coolant feed, etc.) but nothing major or substantial. I was looking at it and decided that there's plenty of room to stick a T3 directly in front of the motor as there's lots of room between the block and the radiator. Got to doing more research on the finer points and it seems to be perfectly do-able.

About 6 nights ago, in the middle of our trip to Colorado, I got online and found Nico forums plus QR25DE (Scott Meyers') turbo build thread and this bolstered my confidence even more. Even though I gather there's only been a handful of folks who've undertaken it, it seems do-able.

I wanted to toss out my preliminary notes so far and get some input from those of ya'll that've either explored it or have actually done it. I am not new to doing major projects on cars as I do the equivalent of this, with more complex turbo and EFI setups, on the Mazdas I build, so I'm not faint of heart concerning the level of detail, work, and money involved. It doesn't intimidate me. In fact, it's exciting to take a bite into the challenge.

The target I've got is ~250fwhp running at about half a bar of boost with a completely turn-key setup that she can get in, start, drive, and enjoy, without the bullcrap of a lot of cars that have buttons, switches, and multiple gauges one has to stare at.

Here's what I've got so far:

Turbo
Hitachi HT18 modified for a T3 mid-range hotside - I talked to a buddy of mine, Bryan who said it'd be a good fit. The HT18 turbo is a larger sized T3 that's native to the 2nd generation Mazda Rx7 coincidentally enough (86-91 Turbo II model). This unit would remain internally gated and sprung between 5-7psi.
The factory hotside would be changed out w/ a T3 type, unknown A/R as of yet.

ECU
I looked at Scott's setup first since he's actually done it and gleaned some good information. However, unless the Apex'i S-AFC has made a major change since they first came out a little over 10 years ago, I'm not particularly a fan since it's an injector DC vs. engine RPM only piggy back. That'll work fine when using one engine load but with turbocharging/forced induction engine loads can vary as boost loads vary. I would have rather finer, pin-point control of the injector at X rpm vs X boost and be able to fully tune it. The second issue has to do with spark advance; I have no idea if the factory computer understands positive manifold pressure although I highly doubt it since I've seen no MAP Sensor anywhere. This is a concern of mine since, as the rule of thumb exists, there needs to be at least 1* of ignition advance per 1* of boost increase. If, for example, the factory ECU fires the plug at 25*BTDC at WOT (wide open throttle) from say 2k to 6krpm, then at 7psi of boost I need to see 18*BTDC at least being fired at the plug.

Per Scott's suggestion, I looked at UpRev. It's a much better option and right up my alley and it appears to yield more control. However, I'm not sure if it's MAP based or not. I'd prefer to have control over every aspect. So, I've decided on building a patch loom harness, with the stock ECU still intact, alongside a Haltech Sprint 500 standalone. I can wire in an extension harness and run both ECU's: the stock ECU will still have every input sent to it, so he'll still be in his blissful happy place, thinking he's doing everything, when in fact the same critical inputs (water temp, air temp, 5V TPS out, and trigger) are sent to the Haltech with the injector and ignitor/coil outputs being stolen by the Haltech.

http://www2.haltech.com.au/index.php?op ... &Itemid=88

Oil feed and drain
Oil Feed I'll block tee off of the oil pressure switch alongside the oil filter, install a -4AN one-way oil filter, and build a -4AN line straight to the turbo, using a 0.08" restrictor at the top of the turbo's CHRA.
The drain looks like a pain in the a**. Will probably wind up getting a used upper oil pan, punching a hole in it and tapping to 1/2", then plugging it until it's time to install the turbo, then adapt it from 1/2"NPT to -10AN and do the drain as such.

Intercooler
There's a zillion bar and plate intercooler cores up on eBay. My last search I think pulled up over 7,000 of 'em or something. Anyways, I'll stick with air-to-air as it's 100% turnkey and will use a moderately sized core with either 2" or 2.25" piping. Piping routing so far looks moderately challenging but I'd like to keep everything on the driver's side if possible.

Fuel System
It appears the Altima has a returnless system! Change out the factory injectors with something in the 400-500cc/min range. Coincidentally, the 2nd gen Mazda Rx7 injectors are 460's (for non turbo) and 550's for turbo, both top fed and high impedance. Does anybody know the factory injector rating?
Also, will change to an aftermarket rail, install an FPR and set it to a base pressure of 40psi, and then install a -4 aluminum hardline return line under the car with the fuel pump sending unit modified w/ a -4AN bulkhead added for a drain line.
Fuel pump considering using any of the NipponDenso pumps off the Rx7 or the Supra. A Walbro 255lph "hot" pump is good for about 485rwhp on our cars which is completely and massively overkill on this little 4-banger.

... and that's what I've got so far. Any input or thoughts? Would love to hear 'em. Once I get started on it (half the battle is convincing her to let me tear into the car although she's almost there) I'll be posting up pictures commensurate with every other normal build thread.

B

[BDC Motorsports]

My beef with using an oil filter sandwich and/or tee'd pressure input from the oil pressure switch galley is that in both cases the oil is unfiltered. The oil filter I'd like just for the turbo is this:

http://www.amstreetrod.com/230106ERL.php4#230210ERL

He can be looked at and cleaned out during every regular oil filter change if need be.

[downedzephyr]

looks like you've done your research... make sure you do document this build, i'm curious to see how it goes!

[QR25DE]

Oh he will document or I will go to Texas and sabotage! :P Should be awesome though. Hope it goes smooth. Very interested to see how the Haltech performs.

[BDC Motorsports]

looks like you've done your research... make sure you do document this build, i'm curious to see how it goes!

You and me both. Everything always looks better on paper than it does being tossed a serious curveball in the real world. I'm trying to plan out the installation stages of it. Am considering doing the oil feed and return portions first (buy a 2nd upper oil pan to modify and plug), then install an intercooler that can remain plugged sans piping, then the turbocharger and piping hardware (run the car with no boost just yet!), then finally the components of the EFI system (pump, injectors, wiring on the Haltech Sprint 500, return line and fuel pressure regulator). It all sounds great on paper but I suspect I'll be bitching during the last two steps per having a wife that now has a downed car she can't get to work in.

B

[BDC Motorsports]

This is the boost gauge my wife likes:

http://www.jegs.com/i/VDO/918/150101/10002/-1

[downedzephyr]

it's very simple. personally, i would spring for something digital, but then again i doubt she's a hardcore tuner, so she doesn't really need anything too flashy.

[BDC Motorsports]

it's very simple. personally, i would spring for something digital, but then again i doubt she's a hardcore tuner, so she doesn't really need anything too flashy.

That's exactly it, Zephyr. She just wants something simple that shows when she's boosting. That old school VDO gauge fits perfectly. No frills, cheap, and shows boost. Also not needle bouncing all over the place in vacuum while she's driving so it's less distracting I guess. Helps keep the dash a bit more elegant.

B

[BDC Motorsports]

I'm plotting and scheming today looking up how I want to convert the fuel injection setup from returnless to closed loop.

http://www.upgrademotoring.com/performance/sard_reg.htm
Buddy of mine has an almost new SARD fuel pressure regulator (for EFI systems) that has two -4AN inputs and a -4AN drain. I believe they're adapted to 1/4" hose barbs already. I'll mount him somewhere near the driver's side probably on the firewall.

Here's the way I'm doing the return:

http://www.amstreetrod.com/100031ERL.php4
http://www.amstreetrod.com/581803ERL.php4
http://www.amstreetrod.com/981908ERL.php4
Using 1/4" aluminum hardline (tubing) for the flat underside of the chassis. Will flare out the ends and run the tube nut/sleeve combination on both ends to adapt to -4AN line. One side will go directly to the drain on the FPR and the other will snake above suspension components and what have you in the rear to make its way to the fuel pump sending unit.

http://www.amstreetrod.com/983303ERL.php4
Modify the sending unit by poking a hole up top and adding a -4AN 90* bulkhead fitting. The top of the bulkhead will have the tail end of the -4AN flex line coming from the newly-added 1/4" AL hardline underneath the chassis.
From there, I'll figure out how to shoehorn however many more inches of 1/4" aluminum tubing I need to make a drain dump from the sending unit straight down to the bottom of the baffle in the tank. Shouldn't be too hard but from what I can tell there might be some space restraints.

The only other part is finding a fuel rail replacement or modifying the existing fuel rail to stick either a 1/4"NPT female thread or some other hose barb or weld fitting on the end to then run a 1/4" / -4AN line to one of the feed inputs on the SARD regulator.

Install a goofy gauge in the 1/8"NPT gauge port on the regulator, set the static fuel pressure (engine off; pump on) to 40psi and call it a day.

Easy as pie.

[dldjros69]

i have no idea what the hell u r talking about!

[QR25DE]

i have no idea what the hell u r talking about!

Isn't that a surprise lol.

[BDC Motorsports]

i have no idea what the hell u r talking about!

Heh heh. Ok -- A returnless fuel injection system is one where the fuel rail is the blunt end of the series. Basically it goes like this:

Tank (with submerged pump) -> Pump outlet -> hardline -> Fuel filter somewhere -> flexible line in engine bay -> fuel rail w/ injectors

In this model, a variable resistor pack can be used by the ECU to modulate pump speed and system pressure depending upon load and RPM. It's becoming a more popular setup on the newer EFI cars. However, the still more common one is where the fuel rail isn't the end of the system but a fuel pressure regulator more or less is. After the fuel rail, another flexible hose will come off its end and travel to the input of an FPR (fuel pressure regulator). The FPR, a spring-loaded diaphragm, restricts the amount of fuel that's dumped out of its gravity-fed dump that runs its way all the way back to the tank. Basically the whole system recirculates and the FPR is the guy that modulates pressure in the system from itself backwards through the fuel rail, filter, hardline, etc., all the way back to the fuel pump output in the tank.

The FPR will have a vacuum line on it so when it gets higher vacuum it drops pressure and, conversely, with manifold pressure it will raise pressure. This serves two purposes - extend pump life (by reducing pressure under varying vacuum loads) as well as assist in injector output by raising the fuel system pressure 1psi per 1psi of boost increase in the intake manifold. With the 1:1 ratio, the injector duration doesn't have to be dramatically increased to fight against pressure that is now combating the bottom of the injector and attempting to keep fuel in the injector.

That all make sense? I'm interested in converting the system over to a closed-loop with a regulator and return line so I can wire the Haltech's fuel pump relay straight to the fuel pump, bypassing any stock ECU operation, and control pressure with the regulator and its vacuum line. It sounds a lot more complex than it really is.

B

[Madhatter969]

No help here for your project, but sounds like it will be awsome. i believe that one of my good friends here in arkansas had his fc built by you? blake ring a bell, clean black second gen, insane motor with a gt35r?

[BDC Motorsports]

Blake, that's him, I did the motor and did part of the Haltech install back over 2 years ago. Small world!

[Madhatter969]

It defanitly is, he and I have talked of your epic rotary building abilities for hours. I'll let you guys get back to your discussion, sorry for thread jacking. Just on a side note, I bet that this turbo idea will come together impressivley, judging from the motor work you blakes car. good day sir!

[BDC Motorsports]

It defanitly is, he and I have talked of your epic rotary building abilities for hours. I'll let you guys get back to your discussion, sorry for thread jacking. Just on a side note, I bet that this turbo idea will come together impressivley, judging from the motor work you blakes car. good day sir!

I hope so. Thanks for the compliment. Once I get some benchmark data, I'll start posting stuff up. Will also start exploring the cheaper stuff to begin with like boost gauge fitment. Can't decide where the heck I (well, WE since it's her car and not mine) want it.

B

[Madhatter969]

No problem man, I hope everything goes well for yah, and I will be checking back soon in hopes to see some headway on the project! Everything's better with a turbo strapped to it

[lavon_andy]

I'm curious to how this works out, seems like you know what you're talking about for sure (I have no clue so can't help haha). Just wanted to post since you're located near me.

[BDC Motorsports]

I'm curious to how this works out, seems like you know what you're talking about for sure (I have no clue so can't help haha). Just wanted to post since you're located near me.

Thanks, Andy. If you have any questions and would like me to explain something, I'll do my best here.

I take it you're at Lake Lavon/Garland area?

[lavon_andy]

Yeah right on Lake Lavon actually; hopefully I'll learn something from this thread even though I have no plans on going turbo lol

[BDC Motorsports]

I hope to be helpful. If you have questions, just ask.

[BDC Motorsports]

Got the pair of MAF adapters today. They were a cheap score on eBay for about $6 or so each with standard USPS shipping. They come with a rubberised gasket, too. Haven't measured the OD of it but they look to be 2.75 - 3".

[QR25DE]

Updates?

[BDC Motorsports]

Hey Scott, haven't done much in the past couple weeks. However, I did find that Boomslang (http://www.boomslang.us/extension.htm) makes an extension harness that will work with the '03 model Altima. It's the same one they make for the '02-'04 Sentra I think if I have the years correct. This will be the guy I'll wire the Haltech inputs into and the stock wiring harness outputs out of. This is what allows the use of a standalone (or piggy back!) on a newer model car with an integrated ECU whilst not damaging or modifying the factory harness in any way. It allows for backwards compatibility too. If I want to remove the Haltech someday and go back to stock, it's as easy as unclipping the extension harness.

B