Boosting R33 Gtst Questions

[zebra]

yeah my car had PFC, 11.8:1 AFR tune at heathcote drags was running 105mph at dead on 1 bar, swapped the dump/front in the pits went back out and was doing 103mph same AFR and boost...so i did infact go backwards..but due to it being later in the day when it was warmer we can take the temperature into consideration

[Brezza]

when i first bought my GTR it came with an Apexi Stainless front Y-pipe, standard cat, and 3.5 inch cat back exhaust (rusted) and with holes in it.

i replaced the cat back exhaust with a 3in stainless cat back and 3.5inch muffler. noticed no difference at all.

exhaust blokes told me the only thing holding me back is the standard cat, they explained it this way,

"think of a garden hose spraying water, and what happens when you put a kink or pinch the hose together?"

because the standard cat wasnt the same diameter as the rest of the exhaust the front pipe and cat back were pretty much useless, they had probably a little gain over standard diameter exhaust and obviously changed the sound but flow wasnt at its best.

then changed the cat to a 3inch high flow metal cat. noticed a big difference in spool up as soon as i left the exhaust workshop.

i've since got dump pipes when my turbo's were changed, that little bit wider pipe has made no difference, but i thought i may as well, on a GTR you're only talking 15cm of dump pipe anyways.

if you want the full benefit of a larger exhaust? "do it properly, get a full turbo back exhaust"

that way there are no restrictions.

[DrewII]

any cheap gauge will do the job. very important to at least have something. the turbosmart spec Bs can read boost the old school way

[bradmax]

far out forgot to say i yeah i got a 3 inch exhaust catback.. he said its ceramic.. and that it'll break if i boost it too much..he sed it can't handle more boost.. so i was wondering what would happen if i do boost it and leave the current exhaust? also my mufflers kicked in a bit. does this ruin performance? lol. Thanks for the replies

I am pretty sure he is referring to the type of components inside your cat. Cat's are measured in CPSI which means cells per square inch, the lower the number the higher the flow (I think anyways), so first you want to make sure you get a high flow cat to get the exhaust gases out as quick as possible. Now the internals of the cat or substrate can be made from ceramic or metal with the metal ones more resistant to thermal and physical shock and can withstand extreme temperatures. Having said that plenty of high flow cats have ceramic substrates - have a look at justjap.com - ceramic high flow for $179 whereas metal substrates are closer to $400.

Sooooo, get a highflow cat, for a standard turbo running 11psi don't think you really need a metal substrate cat, save the money and use it to get yourself a 3inch dump/front pipe.

Now having said all this, I am running a stock exhuast on my R33 GTST and the above is what I've learnt as I research a 3" turbo back setup for my own car.

I still don't know whether an integrate dump/front pipe is better than separate components or if a bellmouth is better and lastly if a dual pipe front pipe is better than the single set up.

Hope some of the above helps.

Edited July 23, 2009 by bradmax

[adamskill]

i think he meant my catback was too thin, and if i boost my turbo .. my 3"catback won't be able to handle it and it'll break my exhaust.. lets say if it does break.. would it just be my exhaust? or will it damage other parts aswell.. cos what im thinking is i may aswell keep my exhaust til it does break (if it does) rather than buying a new one.. and i dont have a fmic.. do you guys think i need it for 11psi?

mate stop worrying about "breaking your exhaust"(WTF does that even mean!?) and worry about "breaking your turbo". search the forum and find what mods you need BEFORE you go winding up the boost. your exhaust will not break. also, if your muffler is f**ked, thats somthing that needs replacing rite away. modifing your car isnt as easy as simply adding more boost. adam

[baby34]

Thanks for replies.

do you guys reckon that it'll be safe to boost to 11 psi on my gtst? i've got a catback exhaust (i will be putting down/front pipes) and a pod filter installed..

And an aftermarket heavy duty clutch. would that be enough or will i need a front mount?? As its only 11psi most ppl are saying i dont need a Fmic...

[trel]

You don't need an FMIC. The SMIC does a good enough job for your application... As far as exhaust breaking because it's ceramic... no. You must have misunderstood your mechanic, what he is saying is that your exhaust turbine wheel is ceramic and anything more than about 12psi and you risk smashing your turbo...

Get the front/dump to complete your exhaust, whack your pod and heatshield on get the car breathing right and 11psi will be nice...

Good luck.

[mad082]

i would get a fmic before summer comes. but it also comes down to how you drive. if you drive it like a nanna then even in summer the stock cooler will be fine. if you fang it a fair bit then you will need a fmic. the stock cooler suffers from heatsoak pretty badly which means you aren't seeing as much of a gain from running higher boost as someone with a fmic.

[TTT]

Just to clarify some things that you obviously misunderstood or yourmechanic didn't explain.

1.) The ceramic that will break that he is talking about is the exhaust "WHEEL" of the turbo (the back of the turbo)

2.) your exhaust is too thin?? he is talking about the fact that you still have the stock Dump and front pipes (and probably cat).

3.) the reason stock turbo's break is usually due to heat and shaft speed (which causes the heat). If you have the stock dump pipe, it gets a ALOT hotter there when boosted over stock because it does not flow very well and causes a restriction. a restriction in front of hot exhaust gasses causes the area to heat up more.. and so the chances of breaking your "ceramic" exhaust "wheel" is higher.

4.) do you need aftermarket dump/from pipes? no.. but it will free up exhaust flow so it is a support mod for increasing the boost.

5.) do you need an aftermarket intercooler? no. the stock one will be good enough for the stock turbo and 12 psi for usual street duties (95% of your use of the car no doubt).. but if you intent to drag or circuit your car frequently, then an upgrade would be good as you will be on the throttle for longer periods and the stock cooler would get heatsoak.

Your 3 inch cat back exhaust is fine.

Your cat converter (probably a compliance item) is uaully really shit so look in to replacing that if/when you do the front pipes.

Pod filter is not required.. get a K&N panel for the stock air box instead.

what you'e going to find when you go to 11 or 12 psi or actually probably anything over 10psi is that you will get R&R problems (which will feel like a boost cut)

usually around 4500rpm...

so you've got other things to worry about..

[baby34]

Thanks GTST.. i gots da turbotech MBC.. apparantly its a good boost controller and theres no boost cut..?

[zebra]

boost cut / R&R is written into the factory ECU...has nothing to do with the boost controller

[baby34]

whats a boost cut/r&R? Whats it do .. and what problems will i get? How do i fix them etc.. =="

[TTT]

R&R = Rich and Retard (kinda like Paris Hilton but with less skank)

the standard R33 ECU will modify the air:fuel mixture by making it run rich and retard the timing when it senses something outside it's expected parameters.

quick lesson.

air goes in through the air filter, goes past the AFM (air Flow Meter) which sends a message to the ECU saying "Hey bro.. there is 12 air habibs coming your way"

ECU goes "No worries bro.. I'll douse them with 2 bits of fuel and burn the f**kers"

the air (habibs) go through the turbo and get all hot and angry like a bunch of lebs that just did 14 sets of bicep curls in a power cage, then through the intercooler to coll off a little, then in to the motor where they think they are entering a hektik nightclub only to be doused in fuel and burnt and spat out the back of the turbo and out the exhaust.

so..

The AFM (lets say is a Kiwi bouncer.. you know.. tough, but can't really count much) can only measure up to a certain number or air.

when you use a boost controller (lets say a hot chick bro), and you turn it up (reduce the length of her skirt and shrink the top), more air gets forced in to the engine (lots of habibs get calls from their cousins and they call go to this place and try to get in).

The AFM can only count so much and realises that there is too much air going in so sends a message to the ECU saying "Bro.. I only counted 15 habibs but I think that another 10 of their cousins snuck in... I'm not sure hey.. I didn't learn to count that many"

ECU goes "f**k you're a stupid coconut c*nt... now I have to deal with these habibs"

So as the habibs make their way through the turbo and intercooler (no doubt stealing stuff along the way), and in to the motor, the ecu douses them with heaps of fuel and makes all the habibs really wet with fuel.. this means that when they are burnt off, they don't burn well and so come out as darker smoke.

Because of his bad mixture (too many habibs in the one club), the ECU also retards the timing (closes the bar for a while) meaning that everything works really badly... all to protect the motor (hektik club) until the AFM (bouncer) gets his shit together and counts properly.

all this means that your car will jerk as if it's hitting some sort of cut or has a fault..

but it's just your car's way of telling you there are too many habibs.

How do you fix this?

Cheapest = A signal bender of some sort (Apexi SAFC is probably the cheapest)

this is a device which teaches the AFM how to lie to the ECU.

You turn up the boost, and 30 habibs arrive and run through the entry door..

AFM goes to the ECU "Hey bro.. I've just sent through 18 business men hey.."

Ecu goes "thanks mate. I'll give them the fuel needed"

this means that you get a leaner mixture and it all makes more power.

a better choice? after market computer.. there are lots to chose from.. do a search.

the after market computer (replacement for the ECU) is fully programmable and so can adjust timing too.. it can also mean that the coconut at the door doesn't have to lie, but instead, it is send on a few special classes and is taught how to count..

Hope this helps.

[zebra]

LOL best story ever

But you could have had added chk chk boom

[geraus]

sorry to hijack this fourm but.. would a stock r33 bashed out cat make a diffrence? because i bashed out my cat and got a tune...would it be worthless if i put my 3inch catco cat back on?

[DrewII]

i drove around for two whole years with my car boosted to 12 psi. turbo absolutely would not make anymore power.

i never tracked/raced however.

but i did used to drive it hard around town. i know for a fact the car was used for track purposes before i took ownership too. maybe i was just lucky.

[ECR-033]

R&R = Rich and Retard (kinda like Paris Hilton but with less skank)

the standard R33 ECU will modify the air:fuel mixture by making it run rich and retard the timing when it senses something outside it's expected parameters.

quick lesson.

air goes in through the air filter, goes past the AFM (air Flow Meter) which sends a message to the ECU saying "Hey bro.. there is 12 air habibs coming your way"

ECU goes "No worries bro.. I'll douse them with 2 bits of fuel and burn the f**kers"

the air (habibs) go through the turbo and get all hot and angry like a bunch of lebs that just did 14 sets of bicep curls in a power cage, then through the intercooler to coll off a little, then in to the motor where they think they are entering a hektik nightclub only to be doused in fuel and burnt and spat out the back of the turbo and out the exhaust.

so..

The AFM (lets say is a Kiwi bouncer.. you know.. tough, but can't really count much) can only measure up to a certain number or air.

when you use a boost controller (lets say a hot chick bro), and you turn it up (reduce the length of her skirt and shrink the top), more air gets forced in to the engine (lots of habibs get calls from their cousins and they call go to this place and try to get in).

The AFM can only count so much and realises that there is too much air going in so sends a message to the ECU saying "Bro.. I only counted 15 habibs but I think that another 10 of their cousins snuck in... I'm not sure hey.. I didn't learn to count that many"

ECU goes "f**k you're a stupid coconut c*nt... now I have to deal with these habibs"

So as the habibs make their way through the turbo and intercooler (no doubt stealing stuff along the way), and in to the motor, the ecu douses them with heaps of fuel and makes all the habibs really wet with fuel.. this means that when they are burnt off, they don't burn well and so come out as darker smoke.

Because of his bad mixture (too many habibs in the one club), the ECU also retards the timing (closes the bar for a while) meaning that everything works really badly... all to protect the motor (hektik club) until the AFM (bouncer) gets his shit together and counts properly.

all this means that your car will jerk as if it's hitting some sort of cut or has a fault..

but it's just your car's way of telling you there are too many habibs.

How do you fix this?

Cheapest = A signal bender of some sort (Apexi SAFC is probably the cheapest)

this is a device which teaches the AFM how to lie to the ECU.

You turn up the boost, and 30 habibs arrive and run through the entry door..

AFM goes to the ECU "Hey bro.. I've just sent through 18 business men hey.."

Ecu goes "thanks mate. I'll give them the fuel needed"

this means that you get a leaner mixture and it all makes more power.

a better choice? after market computer.. there are lots to chose from.. do a search.

the after market computer (replacement for the ECU) is fully programmable and so can adjust timing too.. it can also mean that the coconut at the door doesn't have to lie, but instead, it is send on a few special classes and is taught how to count..

Hope this helps.

Best explanation ive ever heard.

[MUZT3K]

i have to admit that was the best explanation eva...really helped me understand it better lol. they should teach like that at school

[KiwiRS4T]

Thanks for replies.

do you guys reckon that it'll be safe to boost to 11 psi on my gtst? i've got a catback exhaust (i will be putting down/front pipes) and a pod filter installed..

And an aftermarket heavy duty clutch. would that be enough or will i need a front mount?? As its only 11psi most ppl are saying i dont need a Fmic...

You don't need a front mount at this stage. If you are worried about it get an R34 GTT smic

which will bolt straight in with no changes to piping and will be good for at least 200AWKW.

[Mattw_83]

Best explanation ive ever heard.

I finally understand how it works. Its so simple in my language Well done