Gone too far to turn back now....

Hello all,

At last I've finally got off my lazy fat arse and paid my tenner to become a member and have the ability to post. Which is a good thing really because I've been wanting to ask some questions for some time now concerning a little project I'm undertaking.

I've currently got a '93 JDM TT GZ auto completely stock apart from a HKS super dragger exhaust. Now good though the auto is, I just really wanted a manual, and at the time couldn't afford/wait to find one so I bought my auto and have been reasonably happy with it, and with the exception of the auto box catching me out once and sticking me in a bush, I would have to say it's not bad, good even, but just not for me.

So I was thinking of doing an 6 speed conversion. Now I'm going to have to stop you there because I know there will be many a cry of "sell it buy a manual" but I know this car, I know it's a good car, if I buy another car how do I know if it's a decent one. Truth is you never know untill you've bought it. But anyway it's too late for that now.

I've gone out and bought the following

6 speed Getrag V160 gearbox (the unknown quantity, cause it's 2nd hand and don't know yet how good it is, so if anybody knows of someone who can overhaul it then please let me know)

6 spd Drive shaft

Slave cylinder

Master cylinder

Clutch pedal assy

Brake pedal and pedal rubber

toyota clutch lines

RPS Sport clutch

RPS Lightened flywheel

TRD revcounter

I'm going to keep the stock auto diff for the mo because I might well like the very short ratio, and anyhow how often do I get to pull the top end?? Well OK I might change it after a while

Now I know the stock ecu pulls timing at shift points so I'm looking for something else to controll / replace that, but I'm also looking getting a DSBC id III and powermeter so what ever I get will need to be compatible with that (But most stuff is so shouldn't be a problem) I'm also going to replace the stock fuel pump and possibly get an FSE, and replace the stock injectors if need be. (I'm aiming at being able to run 18 psi very safely with everything very well under control)

Obviously the AEM EMS would sort out the timing and all but I don't like the fact that you loose a lot of stock functionality (trac control for one thing, and others that I don't know about yet), and so would like to know other possible options.

The HKS VPS and GCC setup seem reasonable enough but the set up for these seems horrendous, although I won't be doing it myself anyway, so maybe not such a pain. But does anybody else have any other recommendations? Really I want a system that can sort everything out (fuelling/timing) keep stock functionality, be reasonably user friendly, and be compatible with all the other mods I will be doing or will have done in the future (I really really don't want to install something and then replace it because I've forpassed it.)

Anyway any comments will be well received (apart from sell it and buy a manual, as I said it's too late for that)

Kind Regards

Tony License

Oxford UK

'93 JDM TT GZ auto (soon to be 6spd)

HKS Super Dragger

18" Mille Miglia He3

Later mods may include

Induction kit

SSQV

FMIC

Fluidyne rad

Oil cooler

Clarion sat nav/dvd

TRD 3000GT bodykit

I'll give you credit for being committed.. wanting a TRD body kit too I see, nice £££

Good luck with your project.

Originally posted by Bobbeh

I'll give you credit for being committed.. wanting a TRD body kit too I see, nice £££

 

Good luck with your project.

Like it says at the start of the redline vid

"If you imagine it, you can create it" or something like that. Sounded good at the time but now the old credit card is trying to limp back into the wallet telling me to stop watching so much tele. So the bodykit might be a wee way off just yet.

Anyway thanks for the shout

Tony License

Oxford UK

'93 JDM TT GZ Auto (Soon to be 6Spd)

Tony,

You don't need a VPC (VPC replaces the MAF) & GCC for a Jspec, an F-con or similar is required for the Jspec.

But the AEM should be better than all of em...

Give Kev or me a shout when you want them other bits

Gaz.

Originally posted by TLicense

Anyway any comments will be well received (apart from sell it and buy a manual, as I said it's too late for that)

Maybe sell it, buy an aerotop, and convert that to a manual Seriously tho', good luck with the project - let us know how you get on.

Tony, from what i've picked up from this site, the V160 box cannot be overhauled, its a buy a new one if broke scenario.

However i've yet to hear of anyone who's even heard of a broken one, let alone experienced one themselves.

Originally posted by Gordon Flynn

Maybe sell it, buy an aerotop, and convert that to a manual

If I was going to all the trouble of doing it, that's what I'd do

Ditto. Only worth doing if your car was an aero IMO, otherwise just sell and buy a manual in the first place.

Hi...

There have been gearbox failures but they are rare, I have only heard of one in the UK. Up until recently the Supra gearbox was classified as a non servicable part but I read recently Toyota have produced a parts list for it.

The chances of you buying a dodgy secondhand gear box are remote.

Given that you have actually bought a lot of the parts required for the conversion it's probably better that we get on with the practical advice:

Pump & FSE - fine for 18psi, no need for injector upgrade.

ECU - get a Jap 6 speed TT ECU, why make things anymore complicated and significantly more expensive than they are already with an AEM ECU.

VPC/GCC - Not required - for information setting up these two would be a doddle over an AEM ecu.

Stock traction control - is poor, spend some money on the Racelogic unit.

Cheers guys,

Gavin, thanks for the confidence boost in the gearbox dept. Hopefully it should be a good 'un.

Thanks also to yourself and Gaz for the advice on the VPS/GCC, knowledge is power...

A couple of questions still though, won't running the stock injectors be putting them near or close to 100% duty? I've read on here somewhere they don't like to run much more than 70%? Surely it'll be better to get larger injectors and then run them at a much lower duty?

I'm still no wiser about what to use to re-map the thing. Like I said the AEM is an option, and probably the best so far because it's update proof, no matter what I do to the rest of the car I should be able to reprogramme to the ems to suit more or less)

However, talking to Kevin at envy, he seemed to think it wasn't exactly bug free yet, and maybe to look at other possibilities.

I did think about a blitz re-programmed ecu but then again it is a once only stab at mapping from what I understand. (ie it's not mapped for each individual car, just a generic supra, which I don't like the idea of)

I think as per Gaz's advice I'll take a look at the FCON, but is there anything else out there that might be able to do the job?

Once again many thanks to you all,

Tony License

Oxford UK

'93 JDM TT GZ Auto (soon to be 6 spd)

Around 80-85% duty cycle is the reported max for injectors. A uprated fuel pump and FSE will force more fuel through the injectors for any given duty cycle.

Many people have this set-up on their cars and it works well enough on 440cc injectors, many people also run okay without it.

The stock auto ecu pulls timing a set points to smooth the gear changes. If you change to a six speed ECU that function will not be there. Just buy a stock six speed ECU will be the cheapest option by a very long way.

I think that there was a link to a conversion spmewhere on mkiv.com (the USA site) or the NZ site - this might be useful

cant find at mo - anyone?

Good luck and please stick a few photos in as it progresses as this will be interesting

Also remember you'll need a diff from a 6spd manual and probably a million and one other things.

Cheers for looking in paul and thorin,

Just in case anybody else is looking at doing the conversion the link paul is talking about is this

Mohd's 6 speed conversion

I would take a bunch of digital pictures whilst I'm doing it but mohd's page covers just about everything, and plus I'm planning to get Leon to do all the work anyway (I've proven to myself that I really am no mechanic once too often), I may ask him to do a bit of a photo case book. Either way I'll be more than happy to do a write up with complete costs when it's done.

As I mentioned in my initial post thorin, I'm going to stick with the auto diff, not because I'm doing things half heartedly, but the shorter ratio will improve acceleration by my rational (might be wrong) if it's too short then I'll dump it for a 6 speed diff. I might even look at the TRD LSD. (If you're going to change something change it for the best there is - within reason of course!!)

Anyway as you all can see I've looked into this quite a bit and this is no half hearted post. I know the pro's and con's of doing the conversion, but just need advice on what are the best parts to go for when replacing things.

With GavinL's comments about the stock jap 6 speed ecu in mind, what presssure is the stock jap 6 speed ecu mapped to? Although I only intend to run 18 psi, I would also like to know there is more there. With the Blitz and Tom's ecu's are they similarly just mapped to say stock plus 10% or something like that? I imagine they are completely remapped al over to give better performanc, but what's the max boost they can handle? Also could they handle larger injectors at a later stage?

Also does anybody know if there is a way of workin out injector duty vs boost/engine load for stoichiometric combustion?

All these questions eh? Not bad for my first thread....

Again all comments (except, sell it buy a manual, which will now be abbieviated to the SIBAM method) would be greatly appreciated.

Kindest Regards

Tony License

Oxford UK

'93 JDM TT GZ auto (Soon to be 6 spd)

Tony,

I think you will have problems trying to get any real information on the settings on both of those ECU's.

The limitation with the boost pressure (about 18psi) is with the MAP sensor as well as the ECU. Do either of the ECU's give or recommend an alternative MAP sensor?

It is generally not adviseable to run the ceramic turbo's in excess of 18psi anyway and with any requirement for extra fuel being delivered by the uprated pump and FSE. If you go the bigger injectors, bigger turbos etc etc then I would argue the case for a non standard ecu.

Most people don't get the best performance out of the J-spec ECU as it is because they run them on lower octane fuels that it was designed for.

Hi Tony.

Right as Gav said, it will be easier to use a JDM 6 speed ecu. Make sure it's a JDM one if you get it as the maps are completely different. The next most viable option is the AEM. You really should be talking to JPS Motorsport about this.

Gearbox, pretty bullet proof really. They are all noisey, but strong.

Injectors, be careful that if you upgrade injectors they fit the stock rail. Also be very careful to check the impedance of the injector. The 440's will be near there limit with a Walbro and an FSE, but OK. 1.3 bar is the max on Optimax with a stock ecu and compression, don't think because you have more fuel you can run more boost. It will end in tears.

Good luck and keep asking the questions mate.

Cheers Terry,

I think I'll probably end up going down the AEM route to be honest, although as you said the stock Jap ecu will be easier, I'm not looking for the easy way I'm looking for the best if that is the easiest at the same time then that's a bonus.

As far as injectors and the actual fuelling hardware go, I want to sort myself out with a system that will give more than sufficient flow if need be. From what I've heard / read if I wanted to run 18 psi the stock injectors will be at the edge of their capabilities, so it must surely be better to get larger injectors and map them at a lower duty cycle? Are there any downsides to doing this? Foe example if you had 440cc injectors at 80% duty, would it not be better to have say for the sake of arguement (and by no means as a indication of my intentions) 1000cc at 20% or whatever the equivalent would be to get the same amount of fuel into the cylinder?

I'm with you on the compression though, (I use to have a 185 GT-four and believe me if you're going to start to mess about with boost with one of those you NEED to know about compression ratio's ) I've heard though that the stock internals are as hard as nails. Is this right? What sort of boost can they actually take if you are running with the right fuelling?

I think you may be right about talking to JPS. I spoke to Leon a while ago and he gave me an indication of the cost to change the 'box if he supplied the parts and a cost of just labour if I supplied the parts, but I've not spoken to him since. I'll probably give him a call sometime early this week.

Cheers again Terry,

Hi...

Well if your considering going the AEM route in your car I would be budgeting about £2-2.5k. Whereas a secondhand ECU would be about £200-250.

Any mappable ECU is not going to be an easy option compared to stock.

The stock internals are good for around 600 BHP, what size of turbo and how much boost you want to run to achieve that is up to you.

2-2.5k? That sounds an awful lot? I've seen the AEM for sale for around 2 grand at some places, but then I've also seen it for just over 1 at others...

When you mean 2-2.5k is a lot of that setting it up? I thought it was supposed to be almost plug and play (Well I know that's not the case but a grand in setting it up... that's about the same as setting a motec unit up, and that has about 80 cabillion sensors and wires to splice into hasn't it?)

Well it might be "almost plug and play" on the US spec supra but certainly not on the J-Spec's. You could have a word with Paul Whiffin (although I think he's still on holiday at the moment), and see what was involved with getting it setup for his car.

Originally posted by TLicense

2-2.5k? That sounds an awful lot? I've seen the AEM for sale for around 2 grand at some places, but then I've also seen it for just over 1 at others...

When you mean 2-2.5k is a lot of that setting it up? I thought it was supposed to be almost plug and play (Well I know that's not the case but a grand in setting it up... that's about the same as setting a motec unit up, and that has about 80 cabillion sensors and wires to splice into hasn't it?)

Plug and play is a reference to the ecu attaching to the existing loom, on the UK/US spec only. This does not mean you plug it in and drive away.

There are additional bits of wiring for the new map sensor and you would really need a wideband to make the job complete. Not as much wiring as a Motec by any means but still not cheap.

I reckon £1-1.5k for the install and setup of an AEM (wiring, tuner time, dyno time) and 1k for it's purchase.

80% duty cycle is fine, anything above that is iffy.

I have a mappable ecu and can run 25psi on optimax, but with a lot less timing than stock. 19 psi seems to be the limit at 8:5:1 compression and stock timing. The stock pistons come with an anti det coating BTW. As Gav said, 600 bhp seems OK on the stock bottom end. The engines will take 30 psi of boost if you have the the right fuel, but I wouldn't road race it using that much boost.

Again, Gav is spot on with the cost of getting an AEM and a decent map in it. Leon has an AEM so he is your best port of call.

Thanks once again guys,

Knowing that the AEM is going to cost a grand more than I expected has put a slightly different slant on things, as it will be right at the edge of my budget and won't leave much room for maneouvre if anything didn't go to plan. To be honest I am surprised at the cost of the mapping, I had a dastek unichip on my GT-Four, and although that is just a piggy back and was just fine tuning the base maps, wouldn't most of the settings for the AEM (base fuelling/timing maps all ancillary controls) be downloaded as these would be the same for all supra's and then it's just a case of fine tuning the map's to suit the car, which is pretty much all that you would do with the Dastek, and that only took four hours or so to map. Am I looking at this far to simplisticly?

Terry, you mentioned that you have a mappable ecu on your car, do you mind me asking which one and how you've faired with it (Good / bad / acceptable?) If you'd rather not say then that's fair enough.

Has anybody else out there got any advice on fuelling control?

Kind Regards

The AEM is a complete replacement ECU and should not be compared with piggyback equipment. If you wanted just to upgrade your injectors to 550cc as per the UK spec and trim the fuel delivery with a fuel computer eg Apexi S-AFC, that would be quick and inexpensive.

There are base set-ups available for the AEM in the US but they are for US cars on US fuel not Jap cars on UK fuel. Personally I am waiting for a good UK base map before I move forward with one.

Tony, I have an Autronic SM2, which is different class, but much dearer than installing an AEM. I had a new loom made for it.

Mapping an AEM as opposed to a unichip chip are worlds apart. A proper mappable ECU will do so much more, but getting a good cold start and idle is where the time goes. Remember that the yanks have different fuel, different injectors, different cams etc etc to a JDM.