J30 Performance Mods

[R4v3n]

Hi, I recently just joined this forum and I've had my 95 J30 for a little over a year now. I'm definately very satisfied with my car and about 6 or more months ago my friend pulled up in his new car which was a 1990 300ZX. After bragging about it for a week he finally showed us all his engine and I said: "Hey, that's the same engine as mine!" Well after that day I've been getting into performance things for my car and last week I finally brought it to a chasis dyno (if thats how you spell it). Anyways, I came up with 174.8 @ 6400 horse and 149.7 @ 4800 ft-lbs of torque. I've been told that wasn't too bad, but I think I can do better. I've already done the following:

JWT POP charger cone intakeJWT Ecu upgradeUnorthodox Underdrive pulley systemCustom 2'' mandral bent piping with a 3'' muffler exhaust tip

Now, I have stillen headers on the way and I plan on redoing the exhaust system and getting a dual exhaust going. Also I've heard that an HKS ALC(automatic line controller) helps automatic trans since I dont plan on spending 2 grand on a 5-speed conversion....yet.

Anybody have an helpful ideas for me? I'm planning on spending alot but nothing too crazy like a twin-turbo VG30DE swap. Plus, I dont plan on changing the exterior much, I want to keep that rounded luxury look the J already has, its cool. thanks.

Oh, and I'll post some pics as soon as I fix my damn camera.

[Omar]

Hey, welcome to NICO. Where in Chicago are you? I am in the subarbs of Chicago and also have a J. There few more members here that are from the Chicago area with J's. Eswift is one of them. I would really like to see your car. I have been thinking doing mods as well (whatever I can do).

Enjoy this board. You will find answers to may of your problems. There are many knowledgable people here.

Take care.

Later...

[maxnix]

...a chasis dyno (if thats how you spell it).

The real word is dynamometer, but no one ever calls it a dyna, even if it may be a more correct abbreviation.

It's like transmission instead of transmission - I always wonder why anyone would want to change the sex of their Q45.

[VimyJ]

The J30 already has a true dual exhaust. The pipes just come together at the rear resonator. The exhaust is also stainless steel. It would be pretty hard to improve the OEM set up.

A reprogramed ECU lets the engine rev higher and removes the rev limiter (5000 rpm in top gear).

The new intake is a dubious mod. Much has been written here about it and the consensus is quite a bit more con than pro. The J has a cold air intake OEM and the after market mod ends up sucking in hot engine bay air.

The VG30DE is pretty much maxed out from the factory. Additional performance gains are difficult to achieve.

Mayhem has done the underdrive pulley. Perhaps he could let you know how he likes it.

[R4v3n]

Thanks for the greeting omar, I live in streamwood which is right outside of Elgin.

Thanks maxnix, I never knew the correct word, just the shortened part of it.

VimyJ, you have a good point about the intake, the only real differecence that I like the most is the sound, other than that the performance gain can be outwayed by the hot air it sucks in. That is 100% correct about the ecu, as its main purpose is to up the engines timing. The J does have a true dual exhaust, I just put larger piping and two mufflers instead of one to minimize restriction (again sound is also a major factor as well ). I'll ask mayhem about the underdrive, thanks. The VG30DE is very much so maxed, so noticible gains in horsepower are hard to get, especially since the J is no lightweight honda civic we are talking about.

[Eswift]

again, welcome to nico, good to have another J30 suburbanite on here. (i think we've almost got enough for our own club now)

as far as performance goes, most has already been said above.

i was planning the stillen headers myself, but now i might as well see how it turns out for you. those headers are pretty much the largest gain you will experience without the addition of forced induction.

you can sort of box your K&N in using metal, CF, plastic whatever, and then make a seal with the hood when closed with some rubber trunk trim or similar. an elbow can be stuck through the stock opening into that chamber, to better direct cold air from the wheelwell area. should make the intake much more agreeable.

gotta agree with you, the growl this engine gets under load with a good intake is amazing.

WOT never fails to make me grin.

nitrous is completely possible, although i dont know of anyone who has done it.

any number of methods of supercharging or turbocharging are possible, although extensive modification and/ or AC removal will be necessary.

if you are willing to split with about 600 US, http://www.ess-racing.com/ ...this place can get you manual tiptronic-style shifting with your current transmission. (not too much more than the HKS box, if its still going for about 500 euro)

as far as the transmission conversion you mentioned...would be tough to pull off since the suspension of the J30 lies so close to the firewall. (no place to mount clutch pedal, cylinder, reservior, etc.

pieces would have to be taken from z32 or similar, new driveshaft required, ecu jumped to prevent errors..etc. also parking footbrake would need to become handbrake.

you are right, the J30 is heavy, and at this point it seems noticeable gains will only be seen through forced induction...

[R4v3n]

Headers are definately going to make a difference, I'll post both dyna charts with and without them and let ya know what I got out of them.

I like that idea about the intake, I'll have to try that out.

Nitrous is a cool idea, but that involves alot of work to do it properly and safe. Although I think it would be cool to mount the tanks next to the gas tank behind that panel so nobody could tell

I'll also look into that tiptronic style shift method. Another problem with a manual conversion is the fact that the drive shaft on a 300zx is shorter than the J30, so some custom work is involved costing more cash. You would also have to cut up the interior to find somewhere to mount the handbrake.

I was thinking about how to lower the 10.5:1 compression to a turbo-friendly 8.5:1 to then bolt on some twin turbos from a 300zx, but I'm still looking into that. I know I'd need new pistons but I'm sure I'll need much more work than that because getting it all to fit is going to be a *****. Plus I'll need an aftermarket bumper to mount the intercooler which they don't make for Js, so then I'll need a molding or something to get that to fit. Again, much more work involved.

Anyways, I'll post the dyna chart I got last week today after work (I got a scanner at work, heh).

[Omar]

OneFastJ30, I am waiting patiently. I gotta see this. lol

As Eswift said, we should meet up somewhere and form a Chitown club. lol

Take care.

Later...

[AZhitman]

How about a rear ratio swap?

Does the J have the 4.08 R200 rearend? If not, that'd be a great (and relatively cheap) upgrade.

[Q45tech]

The J30 already has a 3.90 diff gear necessary to cruise at 2250 rpm to provide enough torque.................a 4.083 would add only 4.7% in revs probably not worth the expense.

Just like the Q the realatively short 1st and 2nd gears hurt zero to 60 and quarter mile time..........3422/6=541 rpm per 10 mph in 3rd gear........so 100 mph is 5410 rpm........4.083 would only bump it up to 5665 rpm........................need about a 4.68-4.70 diff gear to minimize quarter mile with only 2 gears shifts.

[Mayhem_J30]

the pulley and ecu are the only two things, that i've done, that seemed to have made a difference on the butt dyno. depending on how much you like the car the way it is now i would say strip her down to loose weight. she could stand to shed about 250-300 lbs. which would be one heck of an accomplishment. maybe that turbo vimy's been looking at.

[diamondj30]

guess its time for me to dyno my car.first to get it back from the shop.hopefully this week.its funny i always thought they would be about 180 to the wheels.pretty close.

[Eswift]

I was thinking about how to lower the 10.5:1 compression to a turbo-friendly 8.5:1 to then bolt on some twin turbos from a 300zx, but I'm still looking into that. I know I'd need new pistons but I'm sure I'll need much more work than that because getting it all to fit is going to be a *****. Plus I'll need an aftermarket bumper to mount the intercooler which they don't make for Js, so then I'll need a molding or something to get that to fit. Again, much more work involved.

actually, it isnt even necessary to replace those pistons to achieve a lower CR. Simply bolt the turbo and turbo manifold on, upgrade the injectors, and use the zemulator to remap the timing primarily, also some fuel and injector values.

in this configuration you will actually see much more HP (350 easily) due to the higher CR. Questions about exhaust valve durability arise, although its been done before, with no reported problems. If detonation is your worry, water injection can be implemented to completely dismiss the possibility.

The actual problems that will arise are: custom piping: intake and exhuast drivers side header/turbo clearance around PS rack and column ECU remapping

other than that, it is entirely possible.likewise, dropping in a VG30DETT is just as possible, and further performance upgrades follow the standard Z32 scheme.

You can fit a nice dual FMIC (front mounted intercooler) in the stock J30 fascia, no need to ruin the rounded luxury look, as you said.

cant wait to see that dyno chart, and keep us thoroughly updated on the headers.

Where are you going to get the custom exhaust work done to make em fit?

[R4v3n]

Actually there is a 300zx performance shop called "Ultimate Z" located about 10 mins away from my house. A guy there said he would be glad to do it, but for a not so good price.

I'm extremely interested in getting this turbo to work. If you would email me all the parts that I'll need to get this damn thing to work, like the best turbo (theres like a million different kinds out there) and where I can get that intercooler. One of the main reasons I haven't been too serious about this is the fact that I might have to change the exterior a bit to get it to work, but now that I know I don't have to I'm more interested. I can get most of the custom work done by a buddy that I work with, and for the ecu remapping I can goto that Z performance shop. As for the detonation worry I would more than likely use water injection just to be the most safe I can be.

About the PS rack and column: is it possible to move stuff around the engine bay to get everything to fit right? I don't know much about that sort of thing and see that as my number one concearn right now.

Price really isn't too much of an issue for me becuase right now I'm working a full time job and another part time job, so my cash flow right now is great. Any idea of how much total price range we are talking here? I mean ballpark obviously because with all the custom work things could easily get out of hand.

Oh, headers will be installed hopefully by the end of next week, Ill post both dyna charts for comparison, the current chart Should be up here in like a day or two (as soon as I can sneak over to my scanner at work)

[R4v3n]

Oh, it would help if I post an email address for you to email info on parts right?

[email protected]

Thanks

[Gadgeteer]

I am totally enthused about seeing the before/after dyno charts. I have been scratching my head over the possibilities to get a little more juice out of my J. My first goals are brakes, wheels & tires and suspension to prep for more power.

Love to see the ideas flowing...

[Omar]

Ok, I am AGAIN into this whole modding my J phase. Before I was turned because I was told it cant be done. If it works, my J is next in line.

One thing though...can our transmission handle the extra power? I paid 1500 to get it rebuilt and if getting more power means rebuilding my transmission again, then I am out of this.

Take care.

Later...

[Eswift]

price range: realisticly 3k+ , unless you spend a lot of time sourcing all your parts and get really super good deals. price depends heavily on how much your buddy will charge you, if at all, for the custom work. also realize that the engine pretty much needs to be out, so there will undoubtedly be down time, as far as not being able to drive it for a while...

I am nearly certain the PS rack and equipment needs to be right where it is. Of course, with the right amount of money, anything can be done....most likely route will be first to see if stock 300zx header and turbo config works..if so..thats the hardest part, the rest is a cakewalk. if not, well...you will need someone good at welding and probably access to a mandrel bender to get some custom exhaust headers fabricated. (optimally both sides will need to be made to make the system balanced and symmetrical. other than that, everything will fit right in.

other stuff in the engine compartment can be moved to help piping issues: battery to the trunk, carbon cannister can be removed or relocated a few inches to get piping through there. everything else is pretty much best left where it is.

yeah, i know of ultimate Z, and pretty much gathered that it was not the sort of place to get custom work done...too $$$$

the transmission should be able to handle a moderate increase in power, as long as it is in great condition to begin with. Similarly, if the transmission is on its way out, this system will likely put it over the edge. that HKS ALC box might help, firm up the shifts, i am not certain what it does...possibly a torque converter upgrade. if my transmission failed on me, i would most likely go the manual conversion route, as this would be the most opportune (and yet forced) time. the life of you transmission really depends on how hard you treat it, how often you manually select gears, rolling shifts, WOT pulls, etc.

I dont want to pull down Ultimate Z here, but i am not certain they will be able to handle remapping your ECU. I dont want to get into unnecessary details, because i dont know how familiar everyone is with the ECU system the J30 and 300ZX employ. I am fairly certain, at least, that UZ does not remap or tune ECUs. THey just install one of the various standard JWT set of maps, and JWT doesnt have maps that will work for a turbocharged NA.

of course, if you drop a whole vg turbo right in, then youre set.

In fact, it is very possible that both methods would end up at about the same price.

[Eswift]

I decided to list everything right here, since there seem to be several interested. Of course, i havent yet done this, just researched it, so there could be some small things overlooked.

. Mechanical Boost gauge. get a good one, intall it in an ever-visible location. switchable EGT and a switchable A/F (between banks) would be very useful in tuning. i reccomend autometer or better.

.Intercoolers. FMIC,either custom or there is a good selection on ebay. take some measurements and go from there. you will need 2 seperate intercoolers, butt up against each other.

.Piping. i would use mandrel bend Al, several places offer it pre bent online, or there are numerous shops around. also important to have a bead at pipe ends so hoses dont pop off. also need silicone hose connectors, lots of em, get good reinforced 2-3 ply ones. do a google search for vendors.

.ECU. either AshSPEC EPROM: for VG30DETT drop in, or Zemulator: for custom mapping (must use dyno and wideband 02 sensors)

.Radiator. would be good to upgrade. possible to swap in Z32 unit or aftermarket. search twinturbo.net

.turbos.best to start with stock Z32, since cheap, rebuildable and readily available. (unless you plan on ever 400RWHP)..can get used ones and rebuild if impellers are good, take offs, or used. ebay and twinturbo.net are good for units, but most turbo rebuild places online really really suck. best to do i t yourself, if you are competent and able.

.injectors.either standard tt z32 injectors from post93/94 models, or nismo 555cc ones, again post 93/94. find this stuff used from same places, or new from vendors on twinturbo.net.

.exhuast valves. could upgrade to TT inconel exhaust valves. I would actually recommend this if the engine is to last for quite a while...new or used, preferably new, along with springs and seals, etc. search NICO for "inconel" to learn more.

.water injection. not necessary on the VG30DETT drop in, but a good measure when bolting the turbos on NA block. aquamist i believe. twinturbo.net might have a group buy on a kit with everything you need in the near future.

.exhuast manifolds. discussed in above post. stock sometimes come with turbos, otherwise its all custom.

.exhaust system/connection/downpipes. completely custom. get a good shop to do the whole thing in mandrel 2.25 or 2.5 304 stainless.

.motor mounts. good time for replacement.

.timing belt, water pump, etc. good time to make sure this is all done as well.

.also, various oil and water lines, maybe oil pan too will need to be tapped for lines to turbos.

this is of course just 2 ways of an infinite number of possibilities, most of which costing much more money.

[Eswift]

also, cant forget about small things like plugs.

also a good idea to get a controller to up the voltage sent to the fuel pump under load. The pump is rated to handle much more voltage than it ever sees in the car, you just need a controller. do a search for "upgrade fuel pump" on twinturbo.net to learn more.

[Omar]

Hey,

You know I was thinking that if there are quite of few of us, it'd be nice if we could get discount on parts (even if we have them custom made) if we did a group buy.

Obviously we would have to be interested and figure out if it will be worthwhile.

It'd be nice having a 300+ hp J30 on the road.

Anyways, I'm just wondering if our transmission can handle it. Anyone have any ideas/thoughts?

Take care.

Later...

[Q45tech]

The 300zxtt used the Q version of the R03R04A transmission..........the J version [R03R01A] is light duty and limited to 230 lb/ft of torque vs 315 lb/ft for the heavier duty version.

Obviously Nitrous or super/turbocharging will require a stronger unit to achieve any reasonable life.

[Eswift]

thanks for the specs dennis.

yeah, i believe the J30 has the 1A. are those trannies externally identical? easily swappable? i would imagine...but i am not certain. If so, then there is the answer. (much easier than the 5 speed conversion.)

i agree with dennis on those limits, although there is a certain factor of safety employed in their construction; it depends on how close you want to cut a line you are uncertain of. for example, many people push the 4A version into the 400's, and i have never heard of major problems. Thus one would think that the 1A has a proportional safety margain...just depends on how much you want to push it.

Unfortunatley, fatigue dictates that, just as dennis said, the "reasonable life" may turn out to minimal under such conditions.

[Eswift]

You know I was thinking that if there are quite of few of us, it'd be nice if we could get discount on parts (even if we have them custom made) if we did a group buy.

i defnitely agree that a group buy would be a great way to go about all this, but everyone would have to want to do this the same way. I personally, am not sure yet which way would be the best...and then there are the aforementioned transmission issues... It definitley would cut costs, especially on the manifolds, and all mandrel bent parts.