SoNotaMechanic

*disclaim*This is all on paper, brain, and theory, for personal learning purposes. dont hate. move this thread if needed, or link me to similar discussions please.*disclaim*

Driving an 86 turbo(stock turbo, full 3" exhaust), and find myself bored between 2000 and 3700 RPM(until the turbo spools).

I want a quicker response from the throttle, and being an owner of an 02 xterra, my idea of a quick throttle response can be attained with the addition of a supercharger. My theory is to rig a supercharger small enough to fit near the belts(independently mounted from the engine), and also assist me with a quicker response at lower RPMs.

Obviously, i aim to make this a sequentially twin charged system (super at low and turbo at high rpm). The reason being, i most likely dont have room for a sequential turbo system(a little powered big turbo), although, with an intercooled twincharged system i may not have room either way.

I know it seems to be a taxing labor for quick response, which is why this is all for personal reference. All of the research ive done has led me in circles. Maybe its not possible to twin charge the VG30ET with efficient results (i refuse to mount a roots type system onto a VG30ET(BLASPHEMY!!), and any independently mounted supercharger is built and spools/boosts around the same rpm range as a turbo).

Hopeless? Any links or info or schematics will help. Im not planning on doing this to my turbo anytime soon. but its good to know ya know?

i also saw this and was inspired:
http://www.wheelsjamaicahost.com/whe...?topic=19746.0

Will my addition of another pulley negate the boost coming from the supercharger at lower RPMs? And also consider the lag from the intercooler as well, when ill be running a stock turbo.

FricFrac

Upgrade to a modern turbo and you can have it all. Tod K is running a custom GT35R on his L28 at around the 600HP mark IIRC with no lag. If you're running the stock turbo you're about 30 years behind in technology.

SoNotaMechanic

yeah my turbo is definately dated. but i have a feeling that even with a newer turbo, i might have trouble pickin up momentum off-the-line.

what is an equivalent in size to my stock turbo compared to a newer one like something from jwt while remaining non intercooled? and once i do get a newer turbo, and i want more boost in the low rpm range, would a root type supercharger suffice if i did not mount it directly to the engine? surely there is a way to connect a belt driven roots or twinscrew to some sort of pipe dinger with an electro-mag clutch pulley and a one way valve, into the rest of the intake(now im just guessing what i could do).

anyway, back to reality. help me out on deciding on a turbo dude!. today, my stock turbo pushed between 5-6psi while between 42 and 58 hundred rpm (using an aftermarket analog gague), ad i do not utilize a boost controller. i try my best not to hit the rev limit(the shift **** starts to vibrate, and by habit, i shift).

once i do get a new turbo, should i settle for a manual boost controller? i kinda wanna keep it low tech as to not run the battery, but i could use the information an electronic or an oldschool fuzzy controller would provide.
any help?

tonsoffun300zx

i just picked up a MBC but im kinda scepticle about it i think im going electronic but trust them if you want i just can't.

hoov100

A ball bearing t25 with an supersplit expansion downpipe, a 60mm throttle body, gutted plenum and a 2.5" pipe from the turbo to the TB setup should help spool the turbo well below 3k RPM.

tonsoffun300zx

you could even go T28 but thats up to you. t28 is bigger by a little bit correct hoov?

SoNotaMechanic

Ive heard that a gutted plenum could disprupt the air flow, but ive always wanted one(but not for $400, any used ones out there?), im just not sure how it could impact smog results or how it could affect my z31s daily driver factor.

Also, ive heard that messing with ported throttles isnt a good idea either, because VGs were built in certain ways to handle certain applications, and any changes involving changing the actual engine will most be good, yet, at the same time mor elikely to destroy your VG. I dont want to over-mod my Z, i just want enough low end punch to k.o. the ricers in Reno off the light. im tired of their welded exhausts, mesh grills with a ghost-type intercooler(theyre invisible!!), or even worse 3 inch diameter exhausts with no sounds of turbos spooling(lag bag)... sound like friggen airplanes.

a t25 is a bit small for my taste, 2 of my buddies run 2 t25's in their twin turbos(one supra and the other a Vr4). but i guess with a bigger intake and a gutted plenum, my response time would kill.

all this info is good, but i also need to know whats in my car now.
a 60mm TB compared to a stcok turbo's what... 55mm? 2.5 inch pipe from turbo to throttle body from what 2"flat? and going from stock to 60 invloves porting right? how do i get this done in a clean fashion?

and ive never heard of supersplit pipes but i looked into it and it seems like a good thing to have maybe? whats on my car now and how is it different or worth getting?

thansk for the awsomeness guys! lookin forward to learning more from everyone. but lets try to swing this back into twincharging...

snwbrderphat540

and if you go twin scroll you can get a quick boost valve that helps with lag by a good 1500 RPM. If you really want to go crazy though make a compound turbo setup

FricFrac

How you "feel" and what is available are two different things. Check out what other guys are running and the results they've been getting with certain setups. Talk to reputable turbo shops and they'll be able to set you up with a turbo for your needs.

If you are worried about spool time then you should be using an electronic boost controller. With a mechanical one you are starting to waste exhaust before you come up to full boost adding delay to your spool up.

If you are going to go down the electronic boost controller road you may as well go with a Mega Squirt setup and replace your out dated ECU as well and have full control over your engine management. Mega Squirt cost the same as most entry level electronic boost controllers yet has sooooo much flexibility in getting every last HP of performance out of your car.

hoov100

It won't affect drivability or smog, all a gutted plenum is doing is decreasing air resistance and promoting more even air distribution.

Your not porthing the TB, you are taking the TB off a KA 240sx or a stanza and porting the inlet of the plenum to match it.

You could go with a twins setup, but that's just more work and money, a single BB t25 (or even a t28) should be more then enough for a quick cheap daily driver.

Going with a mandrel bent intake pipe that is a consistent 2.5" from the turbo to the TB is there to decrease air resistance in the system.

You don't have to get a super split DP, but it is recommended. There are a few different DP designs out there that all increase exhaust flow vs the stock DP.

Here is a stock DP (granted it's connected the z31 turbo is on a l28 manifold)


Compared to a super split or divorced down pipe.






The whole premises for increasing air flow to the turbo and from the turbo to the lower plenum and opening up the exhaust is to decrease resistance which will allow the turbo to spool faster. when it's time to tune the pig, I would go nistune. It plugs in to the factory harness and is just less of a hassle to deal with.

AZ-ZBum

That's an O2 elbow connected to the turbo. The downpipe is the part that connects the elbow to the catalytic converter.

hoov100

And according to nissan cruise control is considered "automatic speed control device" But to the rest of the world it's a little different. A downpipe is a pipe that directs the exhaust gas from the turbo into the exhaust.

SoNotaMechanic

its an honor to see a-z zbum in my thread!!! but i dont want people in here that are just gonna correct everyone and be a smart-a$$... dont start arguing over names of parts, you should argue over whats better for what applications and bring proof so i can learn too. im the biggest dummy in the thread so nobody should be talking down to anyone or correcting anyone but me.

i know what a downpipe is. and now i know what a split DP is. and also i realize what hoov says about a mandrel bent TB pipe, mine looks like 2 half pipes wleded together.

i wanna hit up pik n pull for another turbo plenum to gut and port. id rather have the ability to swap between the 2... just in case. but ive heard once you make the switch youll never want to go back.

so its mostly just about air flow then... right? and then configuring the ECU to use the new larger volumes of airflow?

where can i get my hands on a twin scroll turbo? id like to go compound turbo, but thats a whole lot of math and welding and money and engine space. (do note that my AC compressor is crap and im gonna take it out for more room, ive already removed the CC or "automatic speed controller" lol). but i do want to keep the power steering... i love power steering.

idk. i anyone has a spare turbo plenum for sale or even better, a used gutted one for cheap... lemme know. id gladly come and pick it up form you if youre around the state of nevada(arizona texas cali), i love driving so...

there arent many turbo 300zx's out here in reno, thyre all NA's that think theyre fast with their welded exhausts and no turbos. some guy even posted on craigslist a "shiro special"... too bad it was silver and an automatic with a terribly torn up interior.

i just want to stand out from the crowd... and with a z31 (probably the only true z31 turbo in a 10 mile radius), i already do. but you can stick out like a roaring fearsome beast... or a sore thumb(my z).

just weighing the options, i dont want to commit and then back out after 2 years of hard work, so i have to do a whole ton of brainstorming before i even have the cash to do so..

if you guys know anyone who compound charges, or twincharges their VG30et direct them here. i dont wanna hear about marc form boost logic(im too jealous of him and mad that he uses a 2jz). i never said i wanted to and i dont care for twin turbo's on my Z either, parallel twins are over-rated.

AZ-ZBum

And because if you ask either of the two exhaust companies selling exhausts for a turbo Z31 (MSA and CMPerformanceExhaust) for a 3" down pipe, they'll send you the pipe that runs from the O2 elbow to the cat. That's why. http://www.cmperformanceexhaust.com/...-systems/z-124

And as far as I know, no one makes a replacement O2 elbow for the Z31. Plenty of people have made their own split systems. http://z31.com/mods/turbo/wastegate/

If you don't get the correct terminology, you won't get the correct part when you ask someone for something. That's why it needed to be corrected.Then let someone correct the incorrect information. I wasn't talking down to hoov. I was correcting him.Which won't really make any significant improvements over the cost of getting a custom charge pipe made. You'd be better off spending the money on an intercooler system that would include all the mandrel bent pipes.All VG30 Z31 plenums are the same. Doesn't matter if they're from a turbo or not.The only reason to have two is so that you can work on one while still driving your car. Then, when you install the gutted one, you can gut the old one and sell it. But if you're not much of a mechanic as your name suggests, I would just recommend buying an already gutted plenum. There are a couple people making and selling them. http://store.acadianasportscars.com is one.The ECU reads the airflow from the air flow meter, not the plenum. It's already capable of reading more air than the car uses stock.
Ricer stores. Nah. Just kidding. A good performance shop will be able to source one for you. Just be aware that they are not going to be cheap.And really unnecessary with an appropriately sized turbo.Get one of Satan's top mount exhaust manifolds.I love having cruise control. Great for those long trips. Keeps me from speeding.The only time I miss power steering in my convertible is when I'm parking. I'll get that fixed one of these days, but it's not like the Z31 is a big heavy truck. I have a couple spare plenums, but none that are gutted.People are idiots. Either someone sold it to him as a Shiro or he heard the name somewhere and is using it to get more money. Did you correct him?I think twin charging a Z31 would be a great idea. However, it's a difficult process to make it fit under the hood (although removing the AC stuff will probably be enough) and it's not cheap to do it right. So if you're not willing to pony up the $400 or so for a gutted plenum, I would suggest you stop dreaming about it. You'll only be setting yourself up for disappointment.

Figure a good (i.e. non-ebay) turbo will run you around $500. More for a twin scroll. And then a good supercharger will be another $500 to $1000. Plus all the custom intake piping and mounting hardware, figure around $2000 in parts alone. And if you aren't a capable mechanic or welder, you're looking at another $1000 to $2000 easily in labor costs. And then, if you're trying for more than 300bhp, don't forget to source injectors, new ECU, and new exhaust. So another $1500 to $2000. So now you're in it for at least $5k. Then there's the tuning aspect of getting that ECU to match the injectors properly and give you the best performance. So that's dyno time. And of course, everything costs more than you think it will, so budget at least half as much more. So budget of $7500 and hope you don't go over.

But honestly, what are your power goals?

hoov100

Alot of the bigger turbo's used in z32's use the five bolt t25 exhaust housings from the z31 and thus a large majority of the aftermarket downpipes will fit. (will fit the bolt pattern anyway)

And don't worry "SoNotaMechanic" Me and Az-bum has called each other enough names to make any elementary school student jealous.


I wasn't going to suggest any power levels for him, just super quick spool time and simplicity. If he indeed does go with a BB t25 or BB t28 he should have enough turbo to support probably 250WHP or so safely if everything else is in place.

SoNotaMechanic

it doesnt matter anymore, i cant get my hands on the title...

tonsoffun300zx

part out time!!!

hoov100

Lien sale it to yourself, or apply for a lost title.

SoNotaMechanic

i cant apply for a lost title.

how do i lien it to myself? do i biff up an affidavit saying it was towed? or do i get it towed and purchase it from the tow yard? or should i ask my buddies if they know somebody who can fill out the bussiness end of the paperwork?

i live in NV, and the VIN report didnt have any "brands" on it (not reported stolen or missing or damaged), and also indicated that it was last registered in Washington in 2008 (but not by who).

With having just the car and no proper papers stating my ownership or having paid for it (minus the incorrectly filled bill of sale), what are my options?

tonsoffun300zx

just say it was abandoned in your yard for more than 30 days and you should be able to get a lien title no prob.

SoNotaMechanic

wouldnt that cost me lots of money?

im already 700 in the hole.

AZ-ZBum

Why did you take possession of a car without getting a title?

SoNotaMechanic

cuz at the time i was like "omg! an 86 300zx turbo! even if i dont get the title id only be $700 in the hole!"

and now im all like, "man im $700 in the hole"

but seriously, clean vin, functioning engine... with $700+ worth in exhaust, and suspension...

hoov100

Don't even tell them that. Just get the lien sale paper work. All you need is a bill of sale. if you KNOW it's not stolen, then I wouldn't even bother with that and take a bill of sale down to the DMV and apply for a lost title. It should cost less then $50 either way. I have lien sales many cars and the most I had to pay was $100 and it has back registration.

hoov100

Most states don't even issue paper titles anymore, amazingly.