I get a lot of emails from people asking me where to get a JDM engine but in my opinion, after having done the swap and such, that's not the way to go.

I think the best way to turbo you VG maxima would just be to use the stock engine and turbo it. Reason being, you're already starting with a 9:1 c/r engine. Its not too high and not too low. It'll spool a turbo a lot faster than a low compression VG and you'll retain the stock low end power not to mention you'll have more power at the same boost as you would a stock VG30ET simply due to the c/r being .7 higher.

The low end power is a big concern. I notice a massive difference off the line between the stock VG and the VG30ET I'm using. Its actually quite a bit slower off the line because of it and if I did the turbo setup again, I would definitely stay at the 9:1 compression. If you were to build up a motor I would personally not go below 8.5:1 unless you were wanting to run massive amounts of boost. Even then though... its all in fuel tuning. Supply enough fuel and keep it from detonating and you can run as high boost and compression as you want (so to speak). That's how you're seeing guys like Hal making 500+ hp on a stock block VQ. The VG's are very strong engines and handle a lot of abuse but no engine can handle detonation so keep the fuel supply up.

Basically I think the best way to do a turbo setup on our Maximas would be to purchase two right side (rear) manifolds from a 2nd gen Maxima or a 300ZX. These are the manifolds that go straight to the crossover pipe. This will ensure excellent flow to the crossover pipe. From there you'll need to have a custom crossover pipe made. Two 90 degree mandrel bends from the manifolds to a turbo flange will make this setup just plain sweet. The flow should be unmatchable unless you go with a custom tubular header or really work those manifolds over.

The stock Z manifolds have been proven to flow enough exhaust for 400 rwhp in a Z31 so I wouldn't be a bit surprised if this design will flow even more.

(Many thanks to Dan for reminding me of this): Now for the crossover pipe, you'll want to have a flex section welded on near either of the manifolds. This allows for a much easier time getting it on and off but also adds the ability of being able to allow expansion and contraction when the metal heats and cools. This keeps the welds from breaking and the pipes from cracking and such (and is why the stock crossover pipe comes with a flex section as well.) If you want to go cheap you can probably cut the flex section off of a stock crossover pipe but I would recommend buying a new one as flex sections tend to not last a very long time. Granted the ones on the crossover pipe should last much longer than one on the stock y-pipe I still wouldn't take any chances and go with a quality new unit to ensure no exhaust leaks for maximum power, efficiency, and to keep spool times down.

One thing to note is that the cylinders are offset of each other so when you put two of the same manifolds on the engine one will stick out further than the other (I want to say the front one will appear slightly longer). I don't believe this will cause any problems as using the mandrel bends on the crossover pipe will help equal things out (I'll make a picture to describe this). If you want equal lengths just cut a section out of the "longer" manifold and weld it back together. If you take it to a shop a lot of them will say you can cut and weld cast iron but these are very high quality manifolds and weld incredibly well. I believe they're actually considered cast steel. Once they start working on it they'll realize its some good stuff. (they're too used to crappy cast iron manifolds on ye old domestics or something )

(This is kind of a crude drawing but you should get the idea pretty easily.)



After you get the exhaust dealt with everything else is pretty much cake. All you have to do is decided which route you want to take for the fuel control (e-manage, s-afc, JWT, romulator, Zemulator (I'd probably choose this since its been said to work on the VG), etc. etc.). If you go with the e-manage or s-afc you won't be able to go much larger than the 259 cc injectors due to them being able to only adjust fuel +/- 50%. 370 cc injectors are more than 50% larger than the stock 180's which will make it a bit harder to tune properly. This is where going with a JWT, Zem, or the romulator will come into play.

From there find yourself an aftercooler if you're wanting to run higher amounts of boost (I believe they say anything above 7-8 psi, maybe 10 psi... just depends on the turbo used). If you're going for maximum performance go with nothing less than a true bar and plate aftercooler. If you see a picture of one of Spearco's bar and plates looking through the inside of the core and compare it to a tube and fin you'll be blown away. (I'll get some pictures of this a bit later. There's a picture of a Spearco in Turbo and High tech Performance, I believe, so I'll get that one and show you the comparison with my "hybrid" tube/fin and bar/plate aftercooler that I bought off of ebay).

Having the optimal setup for the piping is a bit trickier due to the design of the intake manifold "elbow" (the aluminum piece that curves to the driver's side and connects to the plastic intake pipe). Reason being is with that elbow no matter how you do the piping, besides running an aftercooler with the inlet and outlet on the same side, the pipes run over the hot exhaust at some point and there can be some extreme bends (180 degrees). This can be fixed if you have the elbow modified to point to the passenger's side or you can simply use an aftercooler of this design:



The only restraint with that design is running multiple pipes through the same hole gets a bit tight, but its not impossible. Probably the biggest piping you need for the intake on these cars is 2.5 inches though so its not too bad. You'll need to get a 2.5 to 3 inch converter coupler to go to the aluminum piece or something similar to hook it up but that's not all that hard. www.hightempsilicone.com has some pretty good pricing on silicone couplers and converters like that and also has some very high quality clamping solutions. I'd personally recommend nothing less than a t-bolt clamp. The constant tension clamp is probably not necessary but if you want to get it for the all out best setup you can.

The exhaust, fuel, computer, and intake has been covered so far so that basically leaves the clutch and wheels/tires. Get a good clutch to handle the power this thing will make (ACT, SPEC, Exedy, RPS, etc.) and some nice, wide wheels and tires to help put the power to the ground without slipping and you'll be set.

Really the only thing you'll have to worry about now is if the Borg Warner POS tranny will survive the power the VG can put out. Import Performance Transmission (www.ipttrans.com) knows of the input shaft bearing problem and can put in a larger, stronger bearing to fix the issue. I'm not sure of pricing so you can just give them a call to see what they charge for that service. They can also build it up even more if you'd like to. For a full buildup I'd say you can expect to pay about $1,500 or so. Expensive... but not as expensive as replacing the tranny constantly and not to mention the headaches it will save. The tranny is one reason why I'm pretty much done with my Maxima.

Hopefully this helps those of you looking to turbo you VG. If you have any questions I'd be more than happy to answer them. You can PM me or email me, either way works.

Good luck to those wanting to turbo their Max!

 

thx, now for the tutorial on what turbo to choose...

 

were you a little bored mark?

 

thanks mark, thats an absolutly amazing writeup...i mayb, hopefully get to use it someday *bookmarks page*

 

not a bad writeup mark... i like your manifold design idea... ;-)

 

 

Care to take a crack at the 'ballpark' pricing for such a setup Mark?

 

sticky this...

 

its in the stickies, I hate lots of stickies

 

more than you can afford pal....

VG30ET

 

A big determining factor on the pricing will be how much of the work can you do yourself. If you can do all of the install work and custom work the price is going to be considerably lower. if you cannot do custom work the price will go up considerably. Its hard for him to put a price on somthing that involves all that custom work and so many different variables.

 

sorry mark...but i disagree with some of what you said here...(please take no offense).

yes you do lose the low end...but keep in mind it's a turbo motor. how much power is made at a certain RPM is HIGHLY dependent on turbo spec. small turbo and power kicks in very low but dies on upper RPM...big turbo will rock the upper RPM but will suck in the low areas. a lower compression will always bring more potential of higher boost levels than a higer CR can...of course there's fuel involved and etc etc.


not bad of an idea...but you'll need to fab up more plumbing and brackets for the turbo. also removing that x-pipe means you're removing the flex section....and replacing it with 2 hard pipes going to the turbo...the pipes/welds will eventually crack due to heat and stress.


yes the castings are VERY VERY high quality.

ok i'll go with this...

messy set up...you don't have to run it that way with the 180 bends and etc...but the location of the turbo i guess you're restricted on where everything would go.

i guess you got a lot of people bugging you enh?

 

yeah, that's exactly what i was going to say. most of the custom work is up in the air. if you do it yourself the costs will stay down substantially. the parts you can buy outright can be priced pretty easily so i'll make a small list of the different things you can get.

manifolds - as low as 20 dollars at www.car-part.com (need 2 Z31 or 2nd gen Maxima right/rear manifolds)
fuel control:
JWT - ~$550
Zem - $600 (would be my pick)
Romulator - $180 (works like the Zem but takes a bit more number crunching to use)
S-AFC 2 - ~$250 to $300 (check ebay for some deals)
E-manage - $250 to $500 depending on how powerful you want the unit to be (to my knowledge hasn't been used on a 3rd gen yet, but shouldn't be a problem to hook up)

mandrel bent pipe - $10 to $20 on ebay for (up to 2.5 for intake and I'd use 3 for the exhaust for maximum flow. most guys have good results with 3 inch exhaust on a turbo vehicle.)
silicone couplers - various prices depending on what you need at www.hightempsilicone.com (very high quality silicone and clamps and very decent prices as well. i've bought from them before and was very pleased)

injectors - depends on what size and such but i'd say no more than 500-600 for a nice set of large injectors.

turbo - t3/t4 w/ .63 exhaust housing (i'd personally go no bigger or smaller than that size exhaust. if you're looking for some major power you may eventually have to go slightly larger but until then .63 will get you the spooling and flow that you want.)

the turboes can be as high as 1,500 or so. depends on what you want. a GT30R would probably make a VG incredible. I'm pretty sure it matched a bit better than the GT35R but i can't remember for sure. the GT35R can still work if you're wanting a turbo that'll handle upwards or 600 hp or more.


nah, none taken.

Yeah, there's always more potential for higher boost with lower compression but we're talking about Maximas here. Most guys aren't going to be getting 400+ hp in the 3rd gens and if they are planning on it, they're going to be spending some big bucks anyways so they can go with the full forged internals, lower compression, built tranny, etc. etc. setup.

With what most of the guys on here will be doing the stock 9:1 compression would be just fine. Especially since its going to a be a street driven car the majority of the time. What's nice about keeping the 9:1 compression VG compared to the 8.3:1 VG-T is that you'll keep good low end for the street, be able to spool a turbo much better, and have much more power than the VG-T at any given point up until you're trying to push some major amounts of pressure through the engine. Even then though, I've seen a lot of TTZ guys upgrade from their 8.5:1 pistons to forged 9:1 pistons and they're making tons of power.

I think the boost levels required to need lower compression pistons would be way higher than what most guys with Maximas are going to run so I don't believe it'll be a problem. I can see it being needed at something like 25-30 psi but with a nicely sized turbo and 15-20 psi, these Maximas will flat out screem and be more than enough for a very fast, 4-door sleeper.

Basically what I'm getting at is that with the 9:1 compression you'll keep the low end making it better for street driving and you'll have good top end with the turbo for nice power through the entire rev range.

(Edit: I updated what the design could look like in the first message and put some info on it. Thanks for reminding me about this.)

Yeah, that's definitely an issue that I've been working on. The idea I have is to just cut off the flex pipe that comes on the stock crossover pipe (to be cheap) or you can just buy a nice, new stainless steel one of the same size as the mandrel bends needed and weld that onto one of the legs coming off the manifold. You only need one for it to work well and on top of allowing the proper expansion and such, it makes it much easier to take on and off. I'll add that to the diagram and writeup and such so I don't lead anyone in the wrong direction.

Which one do you think is messy? The problems are mostly due to the direction of the intake. If it pointed to the passenger's side all of the bends would be nice and smooth and not too extreme plus, the intake pipes would never run over any hot pipes, which can make a big difference. Using that aftercooler pictured would be the only way to keep from running over hot pipes and not having to modify the intake at all.

I get quite a few emails but it doesn't bug me. I do get a lot of emails about the JDM engines though and that's not really the way to go for what most people are going to do.

The only thing you really gain with the JDM engine is lower miles (but even then that doesn't really mean its a good engine) and the JDM VG-T's are supposed to have euro cams but those are only worth about 10 hp, which you would easily surpass with the higher compression of the stock VG.

 

Here's some excellent information on what different compressor maps matched up to the VG looks like: http://www.mygen.com/users/dbruce/my...sor%20Maps.htm

I'd also read this site quite a bit as they have tons and tons of info on turbocharging: http://www.turbomustangs.com/turbotech/main.htm

Also, if you like reading about stuff like that check out Maximum Boost by Corky Bell. That is pretty much the Turbo Bible.

ehh... somewhat.

 

since the turbo and the intake is pointed at the same direction you'll need the IC that goes in and out on the same side..(in your pic). that means you'll need to fish 2 pipes through the radiator support/front area to run the 2 pipes...or bang in a 180 degreen turn for a regular one side in and one side out IC....that's what i was referring to as being messy/cumbersome.

 

yeah, that'd definitely be messy. personally i would modify the intake a bit but, i'm up for doing work like that. if someone didn't really feel like modifying the intake very much they could do the aftercooler with the inlet and outlet on the same side for better performance.

really, you could do the normal straight through aftercooler without modifying the intake its just that to keep from doing extreme bends you'd have to run from the turbo to the passenger's side, then run the piping from the aftercooler to the intake from the driver's side. the only downside to this is that there's extra piping and its running right next to the hot exhaust manifold. at the very least its running through the aftercooler after its ran over the hot exhaust which would be better than running by the exhaust after being cooled.

 

Nah, just more work than I would want to put in the VG, and mostly of a matter of priorities for me. I'm almost twice your age son. I actually have some other responsibilities in life.

But I am enjoying the the Eibachs Mark - and the struts Brian. Driving is alot more enjoyable to say the least.

And now... back to the turbo thread

 

'twas a joke, a-la Fast and the Furious

age has nothing to do with it! my priorities put my job and schooling before my car, and my responsibilities are more than the average 19 year old kid pops

yes, back to the turbo thread

 

so i guess he got out of your check book?

 

i like to look at the pictures.........

 

i was looking at my stock vg today and i saw that the oil filter and the coolant hose that goes to the bottom of the radiator will get in the way of the cross over. what can i do to fix that?

 

i dunno, but your car is very nice man, looks great!

 

-relocate the oil filter
-bend/weld new lower radiator pipe...don't forget to figure out a way to run the hose from the new location to the radiator.

see that's the thing...people think it's so easy to slap on the manifolds and think that it's instant turbo..it's not. you need some brain power to figure out what you're going to do with the stuff that's there now.

while you're at it...might as well ask what to do with the solenoids for the power valve (if equipped) and the egr...also the vacume lines that goes around there and to and from the surge valve. oh and don't forget the front injector harness and the IACV harness.

 

forgot a few things like usual

The oil filter issue is pretty easy. you can get the little threaded "pipe" that's on the Z31's and 2nd gen Maxima's so that you can screw the oil filter right onto the block.

For the coolant pipe you should be able to make the crossover pipe to where it will go around it but if you want it to be a bit lower its pretty easy to fix. Basically what you can do is cut the pipe and put on a coupler to extend it a bit. This also allows the pipe to bend down a bit. For the best, and safest, results you should have the ends beaded and use t-bolt clamps to keep them together. Since I had no way to bead the ends I flared them and use two ss-clamps on each side and have had no problems with it at all. The only difference to mine is that I messed up the orignal steel pipe when trying to work with it so I used some copper pipes that we luckily had laying around.

My dad and I just braized them together and it works wonderfully. From there you'll just need a slightly shorter hose to feed the new pipe setup from the radiator. Since the stock one is shaped you'll need to get one that can be shaped as well. I used one that had a spring inside but would prefer a different design. I know they make some that can be shaped but I'm not sure where to look. The setup I have works just fine so I haven't had to search for any other ways to do it.

Also, on the coolant pipe, you don't have to worry too much about getting it too close to the turbo. Minus possible touching the turbo, melting a coolant line is very hard to do. The coolant running through it keeps the rubber from melting or drying out.

To answer the questions that Dan brought up, for the power valve solenoid you'll actually want to disable it and set the valve up so that it is closed all of the time. This seems to get some better gains on a boosted VG. I noticed the incredible difference between open and closed when my power valve worked. I think the solenoid went out which left them open and I noticed a surprising decrease in power.

The EGR will need to be removed if you can. If it can't then you'll have to do some sort of custom pipe that feeds the EGR since you're changing the manifold setup. Wouldn't be too hard to do, it only needs some exhaust and that's about it.

For the vacuum lines and wiring you can heat wrap the crossover pipe to deter melting. If you want to take it a step further you can get some wire wrap to keep the wires themselves protected. Probably the best way to do it would actually be to have the manifolds and crossover pipe ceramic coated and get some wire wrap to keep the wires protected. That'd be the route I would take but I'm sure there are other routes you can take as well. I had my crossover pipe wrapped since I've had the car together and the only time I melted a wire severe enough to cause problems was when my extended MAF wires shook loose and fell on the turbo. Other than that the wires were far enough away that I didn't have any troubles. For peace of mind though, wrap the wires and either wrap or coat the crossover pipes.

 

ok mark...now you have to explain to everyone how the stock EGR pipe will NOT hook up to the Z31 manifolds and what you need to do to run the EGR tube from the Z31 manfolds to the EGR valve or vice versa.

 

sorry for the late reply, i didn't even notice you had replied to this.

i'll have to take a look at my brother's Z to see how they route the egr valve stuff. i don't believe my manifolds have an egr valve port on it but i could be wrong. i'll check all of it out and let everyone know.

also, i finally found the aftercooler pictures that i was looking for so i should hopefully have those on here soon as well.

 

the intake manifold on the Z is different from the maxima. that means the EGR location to the intake manifold bolts up to different locations.

the JDM version doesn't run a EGR...i assume less/no emission restrictions in Japan. of course out here in the good old US of A they good old boys up top decided to slap on some emission restrictions. so for states w/ emission testing the EGR must be hooked up and operational.

 

oh yeah... i guess that is why there are no holes in my manifold (last couple of weeks haven't been thinking weeks for me. vacation one week and mono the next week made for an interesting time).

technically the egr must be hooked up at all times but you can generally get away with it in states that don't test... just don't do anything that'll make them want to test you.

i believe the spot on the manifold that the egr tube comes from on the Z should make it relatively easy to setup the egr. i'll know for sure later today if i can get in the garage.

 

Awesome turbo how-to post. One thing I didn't see mentioned. I've heard nobody swaps a single turbo or twin-turbo 300ZX engine into a Maxima because of firewall clearance. Because the engine's transverse, either 300ZX engine will run the turbo smack into the firewall; not a bolt-in, instead lots of cutting/hammering/welding. I realize you're custom turbo-ing an NA engine. Does your set-up drop the turbo (or raise it) past a firewall interference, or do you just put the turbo on the front side of the engine. Thanks.

 

the turbo ends up in front of the motor not by the firewall.

 

I swapped in the jdm VG30ET (basically an 87-89 300ZX Turbo engine). In the case of those engines the turbo sits right where the motor mount for the Maxima needs to go. The turbo is also very close to the radiator. Actually, if I remember correctly, the fan shroud sticks out too far for the turbo to clear.

So, to be able to drop the engine in you'd have to make a custom motor mount and get a thinner radiator fan setup or you could do what I did and relocate the turbo. I liked the relocating option because it took the turbo away from the radiator. It was too close to the radiator for my tastes.


I finally got the picture of that Spearco bar and plate aftercooler. I'll try getting some pictures of mine today but you can tell right away how well these things can flow. (sorry for the low picture quality. i had to use my digital camera to take a picture of the picture in the magazine, which seems to never work well.)

 

http://forums.maxima.org/showthread....2&page=2&pp=30

nice setup

 

especially with those top quality motor mounts you had

 

hey, that motor mount worked really well. held the engine in the proper place and uh... didn't allow any movement

i just threw that mount together to see what design i'd need to make it work but then decided to go with a totally different setup.

 

i disagree with making a custom engine mount.

 

yeah, i don't really like the idea of custom motor mounts. you'd definitely have to be a good welder and use some strong parts otherwise that could be pretty messy. ehh... that reminds me, i need to make custom motor mounts for my Z.

 

All you turbo experts, would this be a decent match for my VG? http://cgi.ebay.com/ebaymotors/T4-Ki...QQcmdZViewItem

My buddy said it should be a good match, and since Im only going to be running 250-300HP I should be fine, as its rated to something like 400. Im just wonding if it will spool fast egnough or is it going to be a highway turbo.

If not, what turbos do you reccomend, or which ones have you guys used?

~Alex

 

looks ok...but it's not getting the turbo parts that's the problem...making it all work is the hard part.

 

well mark..i'm actually saying that you don't need to make a custom engine mount.

 

that turbine housing looks a bit too big for our cars. a t3 turbine housing with a .63 wheel should be good. if going with a ball bearing turbo you can probably go tiny bit bigger on the wheel. if the compressor is a true 60-1 it doesn't match up to the VG's very well. something similar to a GT30 would work really well and a GT35 pretty good.

if you mess with the turbo a bit. you can flip the turbo over and it might fit past the mount (depending on the turbo you use) and from there you can do some radiator mods. or are you talking about something totally different? (its been a slow day and i'm lacking lots of sleep so i might be a bit off for a while )