I may have the chance of getting a fair bit of engine work done and just want to pick some brains as to what is correct way of doing what i want.

what i'm after is a responsive engine rather than a lot of horses and understand once i go down this path i can not change the character of the engine.

suggestions so far

high comp forged pistons rather than low

ceramic roller bearing turbos

i understand with this i can not run high boost

nos in the first part of the rev range

i have been told that i will sacrifice top end power, but gain in the lower rev range

bigger injectors but not massive

cam profile

well any suggestions??????

thanks in advance

hi Russ,

 

I think the main thing is for you to decide what you want (responsiveness from the sound of it) and how much peak power you'll go for without sacrificing the low end grunt. Once you get that figure people can guide as to what parts of the engine will need to be strenghtened, and what Mods you shuld be thinking of to get the best result.

 

Don't know why you'd want NOS low down in the power range as that's usually used for anti-lag when using huge turbo's, which it doesn't sound like you want

 

You'll still need the supporting mods though like big intercoolers, bigger injectors, bigger rad, oil cooler etc. Then decide on your turbo's, something like PE1420 (good spoolup, 500+hp) and maybe cams. Not really sure on cams as they usually sacrifice low end for top end, but I think you can get them the other way round too.

 

Sure I've missed loads of things but it's a start.

 

Why are you thinking of a rebuild? Has something gone POP!

i would avoid higher compression pistons on a turbo engine like the plauge!! yes it may give a little low down power increase, but it will limit mid & high end far tooo much for it to be a benifit IMO as you will be limited by the amount of boost you can run!

 

for the power you want a healthy stock bottom end will be fine.

 

cams, will normally sacrafice lower end response & are mainly a benifit with bigger turbos, when you want high lift/long duration to get max air in!

 

I would build around the likes of the JWT 530BB turbo's, for stock like spool up with a nice increase in power across the range.

 

im sure if you ask 20 people on here you would get 20 answers, as there is no "right" answer!! :)

what i want to avoid is missing something while the engines in bits

yes want instant response rather than bhp

turbos that i have my eyes on, new gtr34 tubs meant to be very responsive

as to the peak power god knows ?

is it worth knife edged crank

lightened fly wheel

under drive pulley

air con binned

fan replaced with electric

apparently with the cams can get lower end grunt rather than top end but i'm no mechanic

is there going to be need for larger intercoolers as not running much boost max 15psi

( some discussions as to whether to keep intercoolers or not ? )

as to the nos its beyond me ,might need the giggle gas when i get the bill

all the other bits seem to be sorted big brakes, paddle clutch, straight thru 3" pipes,good suspensions

want to avoid massive injectors and would i need them what are the next ones up from stock and what do they w**k out at ?

 

P.S what does imo mean ?

The cams are hit and miss. I thought they would give you more high to mid range increase, but cams, depending on the profile of them, will really mess up your idle, so I cant see how it helps low end power.

Better intercoolers will increase the performance without pushing the turbos. The air will be colder and more dense and thus have more oxygen.

I also thought NOS was really for higher revs, as I have read articles about when to use it as you are only meant to use it at certain rev ranges.

If you are only running 1bar is there a real need to run GTR34 turbos? I thought they where larger and thus more lag. The 300ZX turbos are quite small and have a good spool up.

The cams are hit and miss. I thought they would give you more high to mid range increase, but cams, depending on the profile of them, will really mess up your idle, so I cant see how it helps low end power.

 

Idle's a long way from "low-end power" - when going for it you should drop into gear at at LEAST 3k...

 

Have you seen the other thread on under-drive pulleys and flywheels - definitely relevant!

 

Is it possible to chip ECU for response rather than high-end power too?

 

If I do anything major to mine I'll be going in this direction too by the way...

Russ,

 

The most important questions are:

 

How much dosh you wanna spend?

 

How much RWHP do you want?

 

Then we can work within these two important parameters!

i don't want to be pulling the engine out again so i'm going to have to fork out for the heart of it and the tubs in one hit at a guess 10k or there abouts

hope to get most of the bits done just leaving what ever bolt on to do

is oxygen going to be problem with nos ??

http://www.300zx.co.uk/forums/showthread.php?t=29862&highlight=pe1420+iconel

 

Take note of my last post!

 

The iconel manifolds and GD downpipes should cut down on lag, along with getting the heads ported and polished!

 

Get the forged pistons and do nothing else to the bottom end it is robust, if you do all of the above you will have a monster of a car, with at least 450 RWHP!

ok - GTR tubs, i may be wrong, but i didnt think these were much of an improvement over stock zed ones, are they sequential also?? - this would be a problem also!

Get some tried & tested aftermarked Z32 ones IMO!!

 

knife edge/balanced bottom end is always a plus if you've got the dosh!

 

lightweight flywheel/pulley - yup, deffo a bonus esp if you want better low down power

 

air con binned - too extreme for me!! i bought a zed BECAUSE of the luxuries you get!! ;)

 

elec fan - im sure theres good evidence to suggest this is not a good idea for zeds due to insufficient cooling.

 

cams - done that bit! ;) :p

 

bigger IC's are deffo a benifit, yes, there is a slight increase in lag due to more air to compress, but the benefits of cooler air outway that many times over!

 

& IMO = In My Opinion!!

 

good luck :D

..

imo thanks for that, i'm a :xxx: when it comes to it and its lingo.

had to ask baggins what lol meant. won't tell you what i thought it was but had my doubts about you lot :nelson:

been in a couple of 500+bhp cars wasn't that impressed, above 4500rpm excellent, below that a bit well waiting for it to happen.nice when the cams come in.

been told told the gtr tubs a slightly larger then mine but spool up far quicker but will handle less boost have stage 1 tubs at the moment

as to air/con it's f**ked at the moment .the car is just for fun, only ever had the family in it twice so comfort is not high up on my list.what i want to do is basicly move the bottom line to the left by 1500 revs or so with 10-15 % on the top hopefully without the torque dropping off to quickly sorry can't be more helpful not to good on the mechanics

what i want to do is basicly move the bottom line to the left by 1500 revs or so with 10-15 % on the top hopefully without the torque dropping off to quickly

 

Could you expalin what you mean by this?

 

Paul what have you had done to your cams?

well i want it respond like a v8 instant grunt along most of the range rather than just the high end. if that makes sense

sounds like you want the turbos spooling earlier, in which case what you should really try before sinking pots of cash into the engine are

 

Manifolds & Split Downpipes (greg dupree - see Smithy)

UD pulley

lighter flywheel

lighter 1-piece driveshaft.

 

That'll shift everything to the left nicely, then to make it go up you'll be wanting injectors and i/c's so you can up the boost by a few more psi :D

Things that will make your turbos spool up quicker are,

 

Iconel manifolds

Greg Dupree downpipes

Get your head ported and polished, along with the lower manifold.

Get a JWT mild exhaust cam along with vernier pulleys, this will make the turbo spool quicker once they are dialled in correctly.

 

If you hate lag then get JWT 500 turbos these have the same lag as the stock turbo, but give more bhp!

 

If you do not need an engine rebuild then do not do one, I don't think the bhp you are aiming for requires forged pistons or bottom end work!

Leave the internals for a start! :) Then junk the turbos - they cause the lag at the bottom end :D No, seriously though, a turbo'd car will never have low down grunt. Porting and polishing the heads could well decrease power in the lower rev range as the air velocity will be lower. Cams, its up to you but I'd leave them alone.

 

Your best approach is to work on the exhaust side of things only. Start with the manifolds, then some nice BB turbos - PE1420s give a nice kick in the kidneys ;) GD divorced wastegate pipes and decat pipes should finish it off quite nicely. You're going to need at the very minimum 555cc/min injectors for this setup. Intercoolers also will need replacing. Top that off with a nice aftermarket intake and lightened flywheel/pulley. One further step would be to fit an NA diff which has a slightly shorter final drive ratio - you'll lose top speed but gain at the lower end. One other thing that will help decrease lag will be an electronic boost controller. With this setup you'll have a very drivable car with a nice kick to it...

 

HTH

 

CheerZ,

 

Andy

[Erm, this was meant to be a PM!]

thanks for the advice, like the idea about the diff nice easy way of changing the ratio

now time to see if the chance comes along, then suck it and see i guess

was trying to avoid larger injectors and intercoolers, but can't have everything the way you want it i suppose

once again thanks

was trying to avoid larger injectors and intercoolers

 

why?

intercoolers didn,t think i would get much benefit from as i,m thinking of 1 bar boost

injectors just don,t want to go larger than i need, but at the end of the day these can always be added once the main lumps done and mapped. see whats holding me back and hopefully change what has to be done

wife does not seem to mind the money prefers it spent on the car rather than the reptiles, so not to many problems there. its just wether the oppotunity ahppens or not

What I would do is get a Motec or other top spec ecu set up on a rolling road to get the lag worked out with correct fuel and ingnition delivery. This will even give you lag-free launch control, depending on how deep your wallet is....

The zx has variable inlet valve timing so cams can be left alone (i've seen a 650bhp zx still with them), though vernier cam gears would be good. Other lag decreasing should be gained from intercooler hard pipe kits with performance ic's wich are not much bigger but that will flow boost better, and lightening the shafts, flywheel, crankshaft and pulleys. Porting the head would do no good to decrease lag.

For higher boost levels forged pistons would be neccessary, or water injection to keep it cool (dunno how well this will work on a zx).

Quality exhaust manifold would be good but expensive.

 

Well it's just what I would do if I had bout 9000 pound....