Changing The Revs The Car Boosts At?

[R33 0wnerrr]

Hey guys,

Ok im not sure about this so i thought id ask,

Iv got a T3T4 turbo on my rb25det r33....its at 7psi at the moment... but the boost only kicks in really late in the rev range at like 6000rpm, espically in first gear,

So i was wondering if I brought a boost controller, would this effect what rev range the boost kicks in depending on what psi im running the turbo at? if i lowered or raised it?

Or is it my setup im running?

The mods i have to the car at the moment are the turbo, front intercooler, 38mm ext.wastegate, screamer pipe, ssqv bov on the hotpipe, full 3"exhaust and other stuff i dont think relates tho

I really just want a simple way to make it boost lower in the rev range if possible?

Thanks for looking guys...my first skyline so am learning!..loving it tho..dont know why i ever had a subaru legacy in the past haha

[(B1) MR_fanny]

6000 jebus...i'd just get out of the car and walk to work...ha well not really but probably think about it. I know with my blitz controller you can adjust gain to make it spool earlier but we're talking about maybe 300-500rpm range. I doubt if it will help you drop it down from 6000 to 2500. I think you may have to look into the springy thing that opens up for boost and adjust that or replace it? No idea what I'm talking about. I'm sure someone will be more useful.

by the way, did you ever get the car tuned when you stuck the turbo in?

[Tangles]

what ECU ?

has it seen a dyno recently to see whats going on, air:fuel, ignition timing, etc?

to bring it on earlier ignition timing adjustments help, same with air:fuel ratio adjustments.

to do this you'll need some sort of ecu tuning, either full plugin or piggyback

apexi power-fc, greddy emanage ultimate, apexi safc+sitc, etc...

[tm_r33]

are u sure its not coming on to boost till 6000 rpm?

could be in dire need of a tune and the car is just sluggish as hell till high rpm?

does the motor sound to be running right?

no nasty ignition, fueling or timing problems?

full boost at 6000 rpm is far from ideal in a street driven car.

[R33 0wnerrr]

thanks for your replys,

Its got the standard ECU... and yea it is in need of a tune.... it back fires alot during gear change, and when i turn it on in when its cold it seems to missfire/be out of time for a while untill its warm when its idleing,\

It seems to be running rich, but when i pulled the spark plugs out it doesnt seem so, but it back fires alot

The car itself runs fine tho...goes along nicely, im not sure if its sluggish getting to high revs or not because ive got nothing to compare it to but u definetly feel the turbo kick in when it does,

I didnt install the new turbo so maybe it didnt get tuned?

Would a dyno tune fix this? and bring the boost in sooner? or do i need a piggyback or power fc etc?

Edited May 23, 2009 by R33 0wnerrr

[R31Nismoid]

problem 1 - stock ECU. You need to upgrade the ECU BEFORE upgrading turbo, so clear problem there

problem 2 - how can a dyno tune fix it, with a stock ECU? again, get a ECU FIRST.

problem 3 - what actuator/boost contol? If its just stock, no surprise there really... but again, ECU FIRST

So, go get a ECU, get it tuned with decent boost control and go from there.

Either way its a t3/4, a hybrid turbo that is highly likely to be a poor 'match' of wheels which wont be helping the situation and making it laggy that nothing will fix

turbo's are the key part on the RB's, spending $800-$1200 on a turbo is not enough, decent turbos start @ $1,700, so im willing to be your turbo is in the 800-1200 brakcet

[daisu]

He says 38mm ext wastegate, that could be a problem if that is leaking.

If you go to a dyno with the factory ecu they are only going to be able to adjust base ignition timing (CAS) and maybe your fuel pressure (if you have an adjustable FPR) Really what you need is at least a piggy back ECU or more preferably a full standalone (powerFC) so you can have it dyno tuned properly.

The other thing is you maybe wasting your time with this turbo.

If you just want something that comes on boost nice and early perhaps you should look at getting a factory RB25 turbo back on it? With the turbo you have now you could put some decent boost into it (especially with the aftermarket ecu) and get some pretty good power out of it. The standard turbo on the other hand is really only good for around 1bar of boost pressure, and will likely run out of puff when you get near redline.

Selling the turbo you have now and getting a standard one would probably result in having change in your pocket. Getting a powerFC is going to cost at least 1k, then dyno time at least couple hundred dollars.

It all depends what you want from the car and how much you are willing to spend on it.

Edited May 23, 2009 by daisu

[R33 0wnerrr]

Ok well i didnt know you cant dyno tune it in this situation with the standard ecu....

So i pretty much need a new ecu... a piggyback or pref a stand alone? what about getting the standard ecu remaped?

i was hopeing for a cheaper fix, guess not!

Oh and how do i tell if my wastegate is leaking?

Oh and will this be doing any harm to my car meanwhile?

Edited May 23, 2009 by R33 0wnerrr

[2gceffy]

welcome to the world of cars where there is no cheap fix, bite the bullet and do it right otherwise the next thread will be where to get my motor re-built

[WARLORD BAS]

go to status tuning and get a nistune done, thats what i have done to mine and couldnt be happier. u wont regret it

[SECURITY]

sounds like you have no idea what goes in inside a car to get it running right, its ok - we all started at that point at some stage.

when i started i thought that getting the biggest turbo, biggest exhaust, biggest front mount and it will be good for 11's.

the things you'll need to run that setup properly is a full programmable ECU, fuel pump, injectors, coil packs, wastegate/actuator as a bare minimum.

you'll be running very rich up until the turbo kicks in then very lean onwards - im surprised you haven't blown your motor, i'd get a compression test done asap to make sure though.

[whistle]

Mate, i think that you should first check out the external wastegate before you go and waste money on a new ECU. It could be as simple as adjusting the wastegate or checking the vacuum line to it. It sounds like the wastegate is not closed.

When you start your car check if there is any fumes coming out of your screamer pipe?

Do you know what size the rear housing on the turbo is? and do have any photos of the setup?

[SECURITY]

Mate, i think that you should first check out the external wastegate before you go and waste money on a new ECU. It could be as simple as adjusting the wastegate or checking the vacuum line to it. It sounds like the wastegate is not closed.

When you start your car check if there is any fumes coming out of your screamer pipe?

Do you know what size the rear housing on the turbo is? and do have any photos of the setup?

regardless he needs a new ECU/remap because of what was said above.

Edited May 23, 2009 by SECURITY

[GTR-32U]

Mate, i think that you should first check out the external wastegate before you go and waste money on a new ECU. It could be as simple as adjusting the wastegate or checking the vacuum line to it. It sounds like the wastegate is not closed.

When you start your car check if there is any fumes coming out of your screamer pipe?

Do you know what size the rear housing on the turbo is? and do have any photos of the setup?

Waste money on a new ECU ????

Sorry mate but it would be a FAR bigger waste of money to not get a new ECU. If its a standard one like he said that tune is out like all hell for that set up and more than likely will lunch the engine

Edited May 23, 2009 by GTR-32U

[whistle]

Well not knowing how much money he has to spend, or if he even wants to spend money on it, i just gave him something to look at before he goes and spends $1000+. Yeah a new ECU is a great idea, but if he can fix the problem quickly it would suit him alot better as he wrote in his first post "I really just want a simple way to make it boost lower in the rev range if possible?"

[R33 0wnerrr]

I brought this car with the bigger turbo installed already, so your saying because the cars running rich to boost then lean onwards and the general tune being so out that your surprised my motor hasn’t blown?

Yes I am new to this... and iv got to start somewhere though, just need to brush up on my ecu knowledge.... Basicly running bigger turbo, is what you need the new ECU for it to be able to be tuned properly to run right? does this count for any new turbo? or all aftermarket parts in general?

If like the post above said, that I get a stock rb25 turbo and swap it, can I dyno on the stock ecu I have now? or is that not recommended?

Thanks for your help guys...I appreciate it heaps

[joeyjoejoejuniorshabadoo]

non stock turbos should always have management...

yes you can get away without it.... but its not wise

[R33S2]

Its to do with how much fuel the ecu gives the motor, this is effected by how much air it has to mix it with and what timing as well, if you have a small (stock) turbo the standard ecu is set to give fuel steadily untill boost comes on, then it loads up more fuel because of the extra air being pumped in, it is set at certain points in the map and corrected by the air flow meter.

With a bigger turbo the whole map is different because boost comes on at a completely different point.

You have 2 choices really, get a stock turbo or a ecu and tune.

[chiksluvit]

I'm in a simillar situation as you, r33 with t3/t4 unknown turbo hybrid which came with the car when bought and hits max boost pretty late..

in my car positive pressure starts to build at between 2000~2500, 10psi@ about 3000 and reaches full 16psi at about 4000rpm.. puts out about 240rwkw

thats with pfc and electronic boost controller tuned, z32 afm and nismo injectors...

its not the mose ideal power delivery curve, a bit more response can probably be had with a more aggressive tune with more IGT, but can't really complain since i dont know the specs of this turbo, all i can see/tell is it uses factory exhaust housing and new intake housing, and i'm suspecting its probably a budget turbo...

so yes.. assuming we have simillar or even the same turbos, this is what a tune with proper supportive hardware can get you

Edited May 24, 2009 by chiksluvit

[Guilt-Toy]

there is a little dial on the side of the stock ecu which changes what rpm the turbo kicks in yo. try and change it and see how you go.