Compression & 1JZ.

[Silent Knight]

Ok I have a couple of questions I have been wondering about before I start with any big-ish sort of work on the Soarer.

Some of you on here might know the answer to some of the questions which may be of help to me.

1. Would it be wise to raise the compression on the Soarer a tad? Is raising the compression as simple as playing around with different thickness HGs or do I need to look at playing around with pistons aswell?

2. Does any know exactly how much the stock 1J internals can handle? I am not interested to know about another guy who could do this much with his stock bottom end I'm after specifics and ratings.

3. If I decided to do a mild-ish sorta cam grind along with the head being polished and ported will the stock ECU be able to handle it and run it safely or would it be an absolute neccesity to get an aftermarket unit instead?

Cheers,

Hanré

[Ako]

These are just my opinions -

1 - Depends on what your goals are further down the track. I'm sure you understand the relationship between higher compression + being more careful with the tune, personally I'd go for stock thickness and running more boost. 2.5L and auto box means you can get away with losing a little bit of low end punch since anytime you plant it, the things going to shift up regardless.

2 - There is no specific "figure or rating" for a 10 + year old engine, as always it comes down to how its tuned. Car A will make 500hp for 5 years, car B which is the same enging but tuned badly will make 500hp for 5 minutes, car C which is tuned impeccably but has had a hard life will make die just as fast. Even a brand new engine doesn't have a firm figure for what power it can safely make past factory specs, its all down to experience. What so-and-so made in his car may well be your best indicator of whats safe.

3 - If you're spending all that cash but sticking with the stock ECU, I'd rethink the budget. More gains to be found in the tuning than headwork, though if you're planning on a new ECU some time in the future then it makes sense to go with the mechanical work first.


Hope that makes a little sense - its just my thoughts on it anyway.

[Silent Knight]

Yes I will definately go for an After Market ECU in the future but I'd prefer doing that after I've done my Single Turbo conversion etc so I can get it all tuned properly then.

I don't really want to keep redo'ing the ECU tune if my stock ECU can handle things for now which is really what I want to know. If it is able to handle a mild grind etc then I'll stick with it for now untill the rest of the work is done then tune properly with a decent ECU.

I'm really after the higher compression to get a better response etc. I'm not planning on taking it way the hell up there but just increasing a tad say from 8:5 to 9:5 or 10:1 or something like that. No higher. Will this cause any negative effects or will it hinder the rest of the modification process in any way in regards to extra strain on the motor?

Hrmmm I would have thought that there is some sort of rating for the 1J @ stock levels. Or an all round recommendation of what the stock internals can handle. This is really just so that I know whether I want to be looking at better internals in the near future or whether I can hold of untill I reach that certain point and then rebuild with the more grunty bits.

[Ako]

Personally I'd call anything over 9.0:1 in a boosted application "enough", the majority of turbo cars come with around 8.5:1.

Most stock ECU's can cope with a mild cam grind / swap, since yours is MAP sensored (well, pretty sure the JZ's are right?) if you go too agressive it'll have issues with the poor flow at idle.

In a nutshell, the stock ECU can cope with anything you throw at it - remember, all it sees is airflow and revs - BUT it won't be ideal. Your lucky you dont have a subaru, they go into a limp mode if you just look at them sideways

As for how changing the comprssion will affect other parts - I'm no expert here, so I'll let one of the REALLY smart guys on here answer that one for you.

I've seen a lot of cars making 500hp on the stock bottom end - hell, theres a 2JZ JZA80 at the workshop across the road from me putting 450kW at the wheels on a totally stock bottom end, no headwork bar cams - not sure how similar the 1JZ is to the 2JZ however.

I'd hazard you could push 300kW @ wheels before I'd start to worry in all honesty, from the 1JZ cars I have seen in the past. Everything is a gamble when it comes to pushing a car harder than stock - but with this engine, its a pretty safe bet it won't go "bang" at the drop of a hat. Depends on if you can afford a fresh engine / have a daily driver at all points in time as to whether you really are comfortable pushing an engine that hard though.


disclaimer : The preceding was just my opinion on things - if I'm wrong, correct me

[rage]

imo the trend of late is going high compression turbo. many euro car manufacters are now using it. for example the new golf gti turbo is running a fair bit of boost with 10:1 compression. its in the tuning. theres some downsides of course, u cant run as much boost, tuning is very important etc, but the upsides are that you have great off boost drivability which means good fuel economy, and better turbo spool.

getting a thinner headgasket and planing a bit off the head would bump the compression up a bit. if thats not enough u will have to go for aftermarket pistons.

the stock ecu doesnt cope too well with changes in the compression ratio, although its hard to say how a specific ecu will react, but it should still run and if u keep the boost low etc, it should run ok until you can get a proper tune.

[MrOizo]

Do the ECU now...
and turbo later on..

thats going to be a better way to do it.

Build a base for the new turbo.

I know alot of people say to do alot of things and never do it

but thins is something you should listen to

[strx7]

better exhuast manifold with longer runners before the turbo will get the turbo to spool earlier. Divided exhuast housing with the front 3 ports feeding into 1, and the rear 3 into the other. put a 2JZGE bottom engine under your existing set up, that'll spool it earlier too. it will also give you extra power and torque, especially lower and midrange

[Silent Knight]

Thanks I'm not looking into a doing a 1.5JZ conversion at the moment and I think it would be pointless to change manifold etc if I'm planning on going single Turbo next year anyway.

[Ako]

Do the ECU now...
and turbo later on..

thats going to be a better way to do it.

Build a base for the new turbo.

I know alot of people say to do alot of things and never do it

but thins is something you should listen to

The mans right. Build up a good base first, then go nuts.

Considering the ECU + install + tuning is the same sort of money as a new turbo + mani + fabrication, I know where I'd be looking first - a re-tune for the bigger huffer won't be much at all, since all the ground work would have already been done.

[Silent Knight]

Ok I was concidering doing the ECU a tad faster. Now I have just find out what sorta price range I'll be looking at for a new ECU.

I won't have the money straight away but shouldn't take long to save up. All I need to know for now is will the stock ECU be able to handle the bits for now before I decide to throw in another ECU.

The reason for this is I'll be doing the headwork soonish and I though whilst I'm at it go for a MHG and if it's feasible looking at raising the compression a wee bit.

Ako you do ECUs right. What sorta prices will I be looking at for say PFC/Autronic/Microtech etc?

Cheers.

[Ako]

You have PM


Stock ECU should be able to survive this work, but I'm no expert. I may try and sound like I know at times, but I'm still learning a lot!

But still, saw something funny the other week though which is quite relevant - RB26 (in a laurel), normal mods, intake / exhaust / intercooler, then needed a new head gasket. While head was off, it got severely ported purely because the mechanic was curious how much more could be pulled out of it, turned out to be something like a 20% flow increase overall.

Poor thing didn't know how to cope with its new lungs The stock turbos actually started surging under light throttle conditions, not sure how the ECU was coping, but it didn't seem too impressed at the time I'm guessing the new flow was sending the cursor off to all new parts of the map where it just shouldn't really be - like the RPM X airflow X throttle just wasn't adding up? I'm sure someone can clue me up a bit here.

Thought it might get you thinking anyway!

[Malcolm]

I think an ECU first would be wise if you're planning to make changes to things that effect the volumetric efficiency of the engine, such as cams, compression ratio etc, because MAP based ECUs don't just see how much air comes in and add enough fuel to get the right mixture, they see how much pressure is present inside the intake plenum, and from a number of known variables it is able to calculate airflow. Changing cams or compression ratio could mean the ecu wont have a proper idea of what's going on.

Think about it this way, let's say you're running 12psi with the stock twins and producing around 300hp @ 6,000rpm.

Let's say you now do a bunch of engine work, change to a large single turbo, and now at 12psi you're making 400hp @ 6,000rpm

The ecu's main inputs; the manifold pressure, air temp, revs, tps, etc will all be very similar to how they were previously, so do you think the ECU is going to inject the extra 33% more fuel you need?

the above example isn't quite true, because you wouldn't be 'making 400hp @ 6,000rpm', you would have enough airflow to make that but without the additional fuel you'll instead just blow the engine - quickly

[Silent Knight]

Hrmmm seems that the plan would be then to get ECU then get it done then get it tuned before driving....

Was hoping to be able to hold off the ECU for a wee while due to funding but I guess it is going to be a neccesity (sp?) for this sort of work to be done.

[Malcolm]

it is the unfortunate reality of modifying cars.

You might get lucky and have it survive until you install the ecu, but you might also have it blow, and then you have to pay to have the engine rebuilt, aswell as buying an ECU.

starting off with something like a powerfc (do they make em for the soarer/1jz?) means you wont have to spend up on tuning or install initially

[Silent Knight]

starting off with something like a powerfc (do they make em for the soarer/1jz?) means you wont have to spend up on tuning or install initially

I was thinking that but I've heard that the PowerFC is not capable of controlling the auto box or shifts. Can't remember exactly which part of the auto the FC has trouble with.

I have see however a plug and play Tom's ECU that drops straight in but my fear is that since it's got a sticker with that name on it the price is going to skyrocket.

I shall have to have a hunt around and see what sort of ECU will be the best. How are the Microtech's compared to the PFC? Especially the LT12...?

[Malcolm]

starting off with something like a powerfc (do they make em for the soarer/1jz?) means you wont have to spend up on tuning or install initially

I was thinking that but I've heard that the PowerFC is not capable of controlling the auto box or shifts. Can't remember exactly which part of the auto the FC has trouble with.

Well that's easily solved, isn't it?

I shall have to have a hunt around and see what sort of ECU will be the best. How are the Microtech's compared to the PFC? Especially the LT12...?

IIRC the LT12 has 3 auxillary outputs, assuming you use one of them for idle control, that gives you 2 spares (microtech boost control is shit so no need to use that). I have no idea whether there is a separate auto trans ecu in the soarer (I bet there is) but I think it would be pretty tricky to make it interface with the microtech. Also with the microtech you will have to wire it in (not plug + play) and the base maps will almost certain need a bit of tuning before being driven much, so there is going to be reasonably significant initial cost (unless either you or a mate can install and tune it)

The other option is to piggy back off the stock computer, I'm not sure which ecus can do this and which can't, but I know some, if not all Motecs can, and that should avoid any problems with transmission control (and any other auxillary functions the stock ecu performs)

[Silent Knight]

Yea the problem is just that I don't have the $$$ for a Motec although I'd love to have one.

And no...she's not going to be manual for now. Maybe once I get sick of the auto but I already a 3K stally and getting a shift kit from Auzzy so she's staying auto for now.

I was thinking piggy back might be the better option for now. I'm still new to the ECU world etc however so I'm not sure which one will handle what.

I need something that will be able to handle some 'mild' headwork eg. Porting, Cam Grind. And then will be able to sufficiently tune fueling/spark/timing etc.

I already have an EBC so that's no biggy I just need something to handle the rest. I have an SAFC II sitting in the room aswell which I doubt will be able to do what I need it to do sufficiently once I get some head work done or will it?

Other option might be that new GReddy Ultimate EManage - again I'm not 100% sure on what this thing is capable of so any ideas is very welcome at this point. Preferably from people with experience in the matter or know about Piggy Back controllers etc.

Thanks so far!!

[Si]

get a rotor

isnt john running a emanage now? how did he get on with that?

they seem to be cheap (same price as SAFCII) just depends on what you can do, and how you can do it.

i cant recall if you have stock injectors or if you have upgraded,

im not too sure on what the stock gear can handle, altho i seem to recall something about 250rwkw being the most the turbos and fuel can handle.

[nite b]

Guess it comes down to how much power you want- or think you want..

Do you need to do cam grinds & head porting? I can see benefits of driveability from more compression. Thinner gasket would be adequate, but worth cost/hassle.
The best thing about these engines is such good reliable power from simple mods!

Fact 1jzgte computers arent a bad thing either.. they have a neat ability to 'learn' to bigger injectors..

How about simple boltons..

Single turbo/wastegate/manifold/440cc 2jzgte injs/600x300cooler/filter/3inch exh/boost cut defender if heading over 1 bar.
All atainable for reasonable dollars, would drive like factory car normally. Reliable & simple. 250+real kw@wheels. Thats plenty of power for easy mods...

[matt dunn]

I'm really after the higher compression to get a better response etc.

If you are after response why go single turbo?
Unless you are aiminmg for super serious performance ans super lag to go with it....??


We ran twin T3's on our old 1JZGTE to make about 450hp on a 100% standard engine in a race car application with a link ECU, not even a linkplus!!!

The current car setup uses twin T25/T28 variation and a 2JZGTE,
and will have dyno results on friday after a retune.

Last time on the dyno it made 310kw atw and had the same torque at 3000rpm as it did at 6500rpm.

Matt