2 Psi Increase?

[senilykSkylines]

Hey guys,

I just bought a gts25t its pretty stock except for a tip...and really enjoying it. However I am told that I can tune the boost up 2 psi before the computer will stop me. If I did this what gains could I expect? 15kw at the rears?

cheers.

[mad082]

if it is stock (stock exhaust, etc) then you won't see that much of a gain from upping the boost by 2 psi. you will see a gain, but not that much, maybe 10kw. you would see a much bigger gain from putting on a full turbo back exhaust and then putting the boost up 2psi. even just doing the exhaust would see a gain similar to what you will get by winding up the boost 2psi.

also the ecu won't start throwing a tantrum until you up the boost by about 5psi, but on stock exhaust a 5psi increase would be stupid.

[Dose Pipe Sutututu]

you can expect higher fuel comsumption haha..

on a serious note, you're better off leaving the boost stock and getting a full turbo back & a good panel filter.. more noticable gains.. that 2psi on a stock car, you won't feel the gains.

once you've done that, then wind up the boost to 0.8bar ~12psi then you'll feel something

[senilykSkylines]

you can expect higher fuel comsumption haha..

on a serious note, you're better off leaving the boost stock and getting a full turbo back & a good panel filter.. more noticable gains.. that 2psi on a stock car, you won't feel the gains.

once you've done that, then wind up the boost to 0.8bar ~12psi then you'll feel something

Would an upgrade of the exhaust manifold be enough?...I don't want it too loud. I think it would be too loud if I did a larger pipe all the way through. Though I could put resonators in. Its sounds just right at the moment.

So I could gain 15-20rwkw with just an exhaust? Sweet.

[Hanaldo]

Manifold upgrade won't do anything, the restriction is after the turbo. There are plenty of quiet exhausts around, and if they are still to loud than just get another resonator put in along with a better quality muffler

[PsYLoR]

No, A full exhaust, hi flow cat, dump pipe and filter upgrade might see that sort of increase. (don't change manifold unless your changing turbo) But you might not even feel much change.

If your chasing the sort of gain an extra 2psi will produce then I suggest looking into the cars handling first, Ie swaybars, tyre/rims, suspension, Hicas lock bar, castor & camber adjustments, Brakes!etc

You will feel a much better improvement doing this.

Then when the car no longer handles like a boat, look into increasing the power. Change the boost from the stock 5psi to 7 psi @ 4500rpm and make it 12 psi from 3000 rpm or whatever and you'll notice a much more rewarding change.

Just do lots of reading on the forums and you will learn a lot.

[MrWindsurf]

I had a 3in fijitsubo jasma cat back when i got my gtr with the stock compliance cat. When i changed out the compliance cat to a highflow I got a fairly decent gain, I noticed the turbos would spool earlier and faster and the car felt much happier. Probably +10 killerwasps

[senilykSkylines]

Does it do 5 psi stock? My stock gauge goes up to seven but the boost only reaches the line half way when the foot goes down... I thought maybe 4? Or are they not 100% accurate.

[simpletool]

The 7 on your gauge is in the units of 100mm HG. Just like distance can be measured in miles, lightyears or KM - the units matter (a lot).

760mmHg = 1 bar. Therefore your 7 = 700mg Hg which is ~13.5psi.

A rough way is to double whatever number it represents on the gauge - then you have psi.

[lookingforboost]

it wouldnt be running 13.5psi with everything stock???

i dont think they are that accurate my reads seven but i am only running 9psi, been on the dyno so i know its 9 psi... or 9.26psi till 4000rpm to be exact.

on the exhaust side i have a 3" dump decat and 3" trust silent power and i think its super quiet cant even hear it when cruzing so you dont have to have a loud exhaust to make power, i think you should get a full exhaust system before trying to wind up the boost the gain will by far be better then winding up the boost and as mentioned before a K&N pannel filter will give you better gains all over the RPM range then winding up the boost!

[senilykSkylines]

Many thanks,

I thought 3 1/2 psi was little low for the power it was wacking out. I find my suspension great... almost too tight on the bumpy northland NZ roads.

So what size exhaust is about right to start with? 3" or 2.5"? I am also told that nissans love bigger intake manifolds.

I just got married so money is not really flowing but i would like to get the car as a project up to 170kw at the rears if I can do it cheaply, but properly.

[mad082]

3" turbo back exhaust, fmic and 12psi will see you up around 170 to 180kw easily.

as for the exhaust being noisey, if you find that you want it quieter after putting on the 3" system, invest in a decent oval muffler. they make things much quieter than cannon does.

[gwilkinson34]

3" turbo back exhaust, fmic and 12psi will see you up around 170 to 180kw easily.

as for the exhaust being noisey, if you find that you want it quieter after putting on the 3" system, invest in a decent oval muffler. they make things much quieter than cannon does.

As long as you don't hit rich and retard... my 34 when fairly stock was great with 185rwkw @ 13psi for about a month, then R+R kicked in hardcore and it just became a pig from 4.5k-6.5k rpm.

A new ECU or (Nistune flash) should definitely be on the cards - people not looking for big power tend to avoid ECU mods but IMHO they are worth their weight (money?) in gold and give a huge performance / driveability increase throughout the whole rev range...

Just my 2c.

[vic stagea mick]

nistune hks silent exhaust and 9 psi and auto stagea 164 rwkw needs front mount for a few more

[senilykSkylines]

As long as you don't hit rich and retard... my 34 when fairly stock was great with 185rwkw @ 13psi for about a month, then R+R kicked in hardcore and it just became a pig from 4.5k-6.5k rpm.

A new ECU or (Nistune flash) should definitely be on the cards - people not looking for big power tend to avoid ECU mods but IMHO they are worth their weight (money?) in gold and give a huge performance / driveability increase throughout the whole rev range...

Just my 2c.

Ya, I have a Z32 chip which I was going to use in my N/A but I will use it in the det instead. Sweet, that stagea sounds like what I am wanting to put out approximately. I hope to do it with a tune and exhaust. We'll see.

[Khabel]

How much difference between getting a jap exhaust vs a custom one from the local shop?

[gwilkinson34]

How much difference between getting a jap exhaust vs a custom one from the local shop?

If you get a reputable performance place to make you up one it will be just as good as a jap exhaust and a whole lot cheaper IMHO. And you'll get exactly what you want.

Just find the right place to do it...

[mad082]

How much difference between getting a jap exhaust vs a custom one from the local shop?

didly squat all. what will differ between exhausts though (talking cat back here) is the amount of noise attenuation that the mufflers have (how quiet they make the car). a big oval muffler will make the car quieter than some cannon from supercheap. unless they really cock up the piping when bending it then pretty much all 3" exhausts will flow pretty much the same.

when you start talking about cat converters and dump pipes then things can change a bit.

[Khabel]

I'm thinking of turbo back

[lookingforboost]

i make 188.5RWKW

3" exhaust turbo back

pod

9psi

everything else is stock

so if you go with a full exhaust 3" good rear muffler oval as said before will quiet it down heaps and air filter upgrade you should be pretty close to your goal and be well under 1k