Going 2 bar boost on a T70

[renxun]

..i had seen alot of guys here in this forum winds up the boost up to 29psi / around 2 bar boost on a stock internal of a 1jz-gte...honestly speaking im damm curious how much my car could make on a dyno with that kind of boost... i expect it would be abit wild ...but i would keen to know wat are the requirements needed to be able to boost it up safely .. here are the list of wat im going to do ... perhaps u guys could give some xtra opinion..

currently im using :,
550cc injectors..
2 x 910 pump
1.6litre surge tank
fuel controllers that control +/- 75% fuel correction
a T70 turbo of course
2jz fuel rail

what is my worry now is my stock fpr and stock 2jz rail couldnt take it... and my injectors too ....besides that are my intercooler piping connections and the intercooler itself will be my concern too ...here not much people going to that extent of boost but in this forum i see heaps of u guys are running mad at those boost.... would appreciate for some guideline

[Shifty]

You will need a better FPR, with the correct fuel pressure those injectors should be good for a safe 650hp (engine). I would get them cleaned and flowed if you haven't already.

You won't make anything like 29psi reliably without a full standalone ECU. Even if you did the result would be sub par and reliability/driveability would certainly be questionable.

You would need some type of funky fuel, there's no way you can safely & reliably run anything above 1.5bar on conventional pump fuel. I'm not saying it can't be done but with standard internals you have no safety margin for even the lightest knocking at those boost levels.

Honestly there is no need to run 2 bar. Your best bet is to run a conservative amount of boost on a well sized turbocharger. If you choose the right turbo you can make at 18psi on pump fuel what another turbo might make at 25psi with C16.

[chris davey]

Why would he need a FPR? If the stock one can cope I don't see a need to change?

Is your T70 actually a 70mm compressor inducer? (the small part of the front wheel) If so, that turbo can make some serious power. Probably around the 800hp mark at the flywheel so around 650-680rwhp mark if the engine is up to it.

The 550cc injectors won't be enough if you intend to run that boost. I have 550's as well and was aiming for 300rwkw on those. Your turbo at 2 bar would make substantially more power than 300rwkw. I would think closer to 400rwkw or possibly over.

As was said, you can't expect to run that much boost on normal fuels. You will need some high octane probably about 110 RON+MON/2 stuff.

Cooler piping etc. just make sure they are all lipped where the piping joins.

RE ecu, if you have just a fuel ecu at the moment you are probably limited. For starters, you will need a FCD to run more than 15psi. This is clamping the MAP sensor at just below the fuel cut. It could be done to run that much boost with your fuel only ecu but it would take a very good tuner to be able to do it. As you are limited by adjusting the stock fuel map which inturn adjusts the timing you could run into knock (detonation) as the ecu would see much lower boost ie. if you reduce it 10% it could think that it is running 13.5psi when it is actually running 29psi. The difference in ignition timing at these boost levels is massive. This is why you could not run normal fuel. At 13psi it may run something like 25deg timing. At 29psi you are probably going to have to run about 14-16deg timing. If you can't adjust it then the knock sensors will send messages to the ecu and pull timing back a lot. This will save your engine (hopefully) but will reduce power. In short, I would definitely get a full standalone ecu before running such big boost

[renxun]

thanks for the feedbacks... actually my mistake... as my injectors are actually 650 and not the 550.. typo error..

and i do have the boost cut eliminator... i understand that the timing will start retarding at that level of boost ...however another reason why im not going for full standalone ecu is because im dont have the capability to have those ecu run around on street as good as the normal stock ecu we are having...so for the driverbility i maintain the stock ecu and normally do "add-ons" to wat is required... and for this case , since its the timing issue can i actually get my self the apexi ITC(ignition timing controller) and start from there..? i mean to reduce the power lost from the ignition retard..

and yess you are correct .. im using the one with the 70mm inducer which had quite a large wheel ..if im not mistaken the nut that fastern my fins are size at 17 if im not mistaken

[oldcorollas]

problems
stock ECU, where the MAP tops out at 15psi (before fuel cut)
run the engine at 29psi.

so you need to make the ECU think it is 15psi maximum, but the injectors need to know it is 29psi.
the igniter also needs timing pulled out, but the ECU still thinks it is 15psi

so you add SAFC or some crap, and reprogram the MAP to voltage curve so that from 1 bar absolute to 3 bar absolute is now the same voltage as 1 bar to 2 bar.
and then you get timing controller to retard the timing along that same curve, so it doesn't shit itself.

and then you put in bigger injectors, so you have to reprogram the pulsewidth for the whole fuel map anyway.....

so all you are saving, by running stock ECU, bigger injectors, SAFC thingy and ingition controller.....
is the timing advance for when youhave no boost?

seems a pretty crappy reason not to go standalone, since you will have farked with all the fuel values anyway.

power loss from ignition retard?
with more boost, you need less advance.
ie, at29psi, you need more retard than at 15psi.
you need to ignition controller to INCREASE the amount of timing retardation.

my opnion is that you are wasting time and money having to reprogram both a fuel and an ignition controller... when you could do the same tuning to an aftermarket computer, and not have any worries about unexpected changes in mapping that the stock ECU might do.

no-one can tune for drivability near where you live?

[renxun]

im from east malaysia.... a state call sabah or known as borneo.... out of date place where most pl dun even know how to operate a window xp..how can i expect them to tune my car?

[30psi 4agte]

im from east malaysia.... a state call sabah or known as borneo.... out of date place where most pl dun even know how to operate a window xp..how can i expect them to tune my car?

Good point.
Ever thought of tuning it yourself ?? or teaching the tuner how to operate the laptop tuning softwear ??

[oldcorollas]

so what is your fuel like?

are you planning to run race fuel?

how do you plan to run 30psi if there is no-one to tune it?

[renxun]

currently all my fuel controlers are all analogue type... and i have my peak air fuel meter to monitor my acceleration ratio.... my fuel here in malaysia are ron97 and ron99..with some octane booster i can make it up to 104.....tats the best i can do for the fuel here....

for the tuning wise i tune everyting myself base on the air fuel reading with my analogue knobs at rpm point....it has a full throttle mode also...

[Shifty]

Why would he need a FPR? If the stock one can cope I don't see a need to change?

If you're going to be running 2 bar you really need to have adjustable fuel pressure for tuning/reliability purposes. As with lots of stuff you might be able to get away with it but that might just cost you an engine.

This is similar to something I deal with at work... people say they're on a tight budget and can't afford insurance... but if you can't afford insurance then you sure as shit can't afford a new house (etc) in the event of something going wrong.

Same with this... a few hundred bucks for a good adjustable FPR & quality gauge might seem like a waste if you're on a budget, but it's cheaper than a couple of grand for a raplcement motor.

[chris davey]

Yeah I see. The reason I said that is because I have heard of a few people having more issues with an adjustable one.

1j's are cheap as chippies anyway

Rexnun: I wouldn't go straight out and run 2bar. If you have 104RON then that isn't that great fuel. I wouldn't run more than about 22psi with that for safety.

I agree with oldcorollas re ecu. Grab a microtech and a wideband and have a go an tuning. I can even send you my maps which are for a single turbo 1jz tuned to 17psi and you could start from there. (you would definitely take it easy first to make sure all is good and safe.)

You can get great drivability out of any ecu that is tuned well. I have found that tuning really isn't that hard if you are careful. And if you are tuning your own engine then you WILL be careful

my 2.2c

[renxun]

thanks man... u had been very helpfull ... another question to ask which is about the cam...if i combine the intake of 254 and exhaust 272 wat would be happening and so on ....i proceeded with both 272 as i see most of the pl running on this combination ... there must be a reason of why some people run on both 264 or even both 256 or sometimes they mix match differant duration cams. i was wondering whats the characteristic like...?

[30psi 4agte]

They will use cams of different durations to achieve different power bands from the engine
Using a 254deg (inlet) cam and 276 deg(exhaust) will keep the exhaust valves open for longer.Some people opt to do this to allow a greater time for the exhaust gas to escape.

The theory behind this in short is with a turbo engine that is running big boost the amount of air being pumped into the cylinders can be more than the exhaust stoke of the engine can get rid of. So a larger duration cam is used on the exhaust to give the engine longer to expell the burnt gas.

This is a very brief explanation as there are quite alot of very detailed articles around on this subject and it would take forever to explain the pros and cons.

Try a search on camshaft duration and have a good read.