R33 GTS25t Maximum boost? - GT-R Register - Official Nissan Skyline and GTR Owners Club forum

RoboPope · 16th November 2002, 12:18 PM

Folks,
Anyone know what the maximum boost pressure the standard R33 GTS25t engine will tolerate providing the head gasket has been replaced with a steel one?

Most of the peripherals are in the process of being changed so hopefully they will not be impeading my quest

Paul

Calv GTSt · 16th November 2002, 05:03 PM

Hi Paul
Im running 1 bar on mine though mine is running standard compression. Im told you can really start to blow em when youve lowered the compression. But how high will depend on the rest of the mods.

Calv

RoboPope · 16th November 2002, 07:07 PM

Calv,
I'd imagine that’s is a similar boost level that mine will come back in, I’ll post the rolling road figures when I get them so we can look at the differences from the last tweak

So how do you go about lowering the compression? I dare say you cannot affect it too much with a thicker head gasket.

Paul

Calv GTSt · 16th November 2002, 08:17 PM

Paul
To lower the compession on these you can fit a thicker head gasget, I dont know whether the head gasgets come in a range of thicknesses, does the one you have ordered maintain standard compression?

I know that by lowering the compression you will loose some off boost performance.

Calv

RoboPope · 16th November 2002, 08:49 PM

Hmmmm.... guess i'll find out although I have absolute faith in them to get it right though. This round of mods started out as a bit of a service and sort the clutch which has been a bit lame since ive had the car. The trouble is that as usual i started to behave like a kid in a sweet shop and so im not sure what to expect yet.

Paul

uk_skyman · 17th November 2002, 07:48 PM

Paul im running 0.8 bar but ive been told thats max on the 'plastic turbo' looking for steels like Calv so i can go 1 bar too....

Dean

ps: dont switch the apexi boost kit off as i reached over 1.4 bar in a split second untill i s**t my self and switched it back on

RoboPope · 18th November 2002, 01:27 AM

Dean,
I already have a needle rollered trick turbo so hopefully i can run higher than that but i dont know what the engine its self can do... sadly without cams all that boost is not likely to be used that efficiently. still that just means another trip to the toy shop

Paul

R34Nismo · 17th December 2002, 03:38 PM

Did I see you in Finch Mr Pope ?

RoboPope · 17th December 2002, 03:42 PM

It is distinctly possible

I spend a lot of time up the California end of Nine Mile Ride

Paul

R34Nismo · 17th December 2002, 03:44 PM

S'pose thats why i live off of Barkham Ride

RoboPope · 17th December 2002, 03:50 PM

yep, that'll do it

swishboy · 23rd December 2002, 05:09 PM

I think you need also a fuel cut defencer, this helps you raise the boost without detonation. Links up to the standard ecu.

hks do one for about £100.

hope that helps.

swishboy

swishboy · 23rd December 2002, 05:16 PM

uk_skyman,

I have the profec b boost controller setup on my r33gts-t and it will only get in to too much boost if i turn the boost controller on, and too high.

Most of the time i have it turned off as the standard boost is limited to 0.7 bar, on stock ecu. I'm gonna get the hks fuel cut defencer fitted and i'm told with my hks head gasket, that i will be able to make 1.0 bar on standard turbo.

Also i have found that to get really impressive boost i select the high end boost as low end just lose's traction

P.s happy xmas skyliners

swishboy

uk_skyman · 23rd December 2002, 06:19 PM

in this weather 1 gear forget hard accelleration 2nd as 1 but in third its ok untill about 6000 revs till the back goes a bit leiry

but heh does it suck at 1 bar or what, the blitz induction sounds great and the blitz blow of sounds much loader now at 1 bar...

merry xmas Dean

RoboPope · 23rd December 2002, 07:12 PM

I dont have a standard ECU, injectors or AFM... plenty of scope to play there I think

bring it on santa

a very festive Paul

16th November 2002, 12:18 PM	#1 (permalink)
RoboPope GTR Register Member Join Date: Sep 2001 Location: Berkshire / Oxfordshire Posts: 477	R33 GTS25t Maximum boost? Folks, Anyone know what the maximum boost pressure the standard R33 GTS25t engine will tolerate providing the head gasket has been replaced with a steel one? Most of the peripherals are in the process of being changed so hopefully they will not be impeading my quest Paul

16th November 2002, 05:03 PM	#2 (permalink)
Calv GTSt GTROC Member Join Date: Jun 2002 Location: Nottingham UK Posts: 396	Hi Paul Im running 1 bar on mine though mine is running standard compression. Im told you can really start to blow em when youve lowered the compression. But how high will depend on the rest of the mods. Calv Last edited by Calv GTSt; 16th November 2002 at 05:10 PM.

17th December 2002, 03:38 PM	#8 (permalink)
R34Nismo GTROC Member Join Date: Oct 2002 Location: United Kingdom Posts: 1,113	Did I see you in Finch Mr Pope ? __________________ ___________________ ..+ +.. HQ is Now Closed Note for Marketing Agencies - McDONALD'S Make your brown carrier bags green in colour so they blend in with the countryside after they've been thrown out of car windows.

17th December 2002, 03:44 PM	#10 (permalink)
R34Nismo GTROC Member Join Date: Oct 2002 Location: United Kingdom Posts: 1,113	S'pose thats why i live off of Barkham Ride __________________ ___________________ ..+ +.. HQ is Now Closed Note for Marketing Agencies - McDONALD'S Make your brown carrier bags green in colour so they blend in with the countryside after they've been thrown out of car windows.

23rd December 2002, 06:19 PM	#14 (permalink)
uk_skyman GTR Register Member Join Date: Apr 2002 Location: Nottingham, UK. Posts: 362	i know the feeling in this weather 1 gear forget hard accelleration 2nd as 1 but in third its ok untill about 6000 revs till the back goes a bit leiry but heh does it suck at 1 bar or what, the blitz induction sounds great and the blitz blow of sounds much loader now at 1 bar... merry xmas Dean

16th November 2002, 07:07 PM	#3 (permalink)
RoboPope GTR Register Member Join Date: Sep 2001 Location: Berkshire / Oxfordshire Posts: 477	Calv, I'd imagine that’s is a similar boost level that mine will come back in, I’ll post the rolling road figures when I get them so we can look at the differences from the last tweak So how do you go about lowering the compression? I dare say you cannot affect it too much with a thicker head gasket. Paul

16th November 2002, 08:17 PM	#4 (permalink)
Calv GTSt GTROC Member Join Date: Jun 2002 Location: Nottingham UK Posts: 396	Paul To lower the compession on these you can fit a thicker head gasget, I dont know whether the head gasgets come in a range of thicknesses, does the one you have ordered maintain standard compression? I know that by lowering the compression you will loose some off boost performance. Calv

16th November 2002, 08:49 PM	#5 (permalink)
RoboPope GTR Register Member Join Date: Sep 2001 Location: Berkshire / Oxfordshire Posts: 477	Hmmmm.... guess i'll find out although I have absolute faith in them to get it right though. This round of mods started out as a bit of a service and sort the clutch which has been a bit lame since ive had the car. The trouble is that as usual i started to behave like a kid in a sweet shop and so im not sure what to expect yet. Paul

17th November 2002, 07:48 PM	#6 (permalink)
uk_skyman GTR Register Member Join Date: Apr 2002 Location: Nottingham, UK. Posts: 362	Paul im running 0.8 bar but ive been told thats max on the 'plastic turbo' looking for steels like Calv so i can go 1 bar too.... Dean ps: dont switch the apexi boost kit off as i reached over 1.4 bar in a split second untill i s**t my self and switched it back on

18th November 2002, 01:27 AM	#7 (permalink)
RoboPope GTR Register Member Join Date: Sep 2001 Location: Berkshire / Oxfordshire Posts: 477	Dean, I already have a needle rollered trick turbo so hopefully i can run higher than that but i dont know what the engine its self can do... sadly without cams all that boost is not likely to be used that efficiently. still that just means another trip to the toy shop Paul

17th December 2002, 03:42 PM	#9 (permalink)
RoboPope GTR Register Member Join Date: Sep 2001 Location: Berkshire / Oxfordshire Posts: 477	It is distinctly possible I spend a lot of time up the California end of Nine Mile Ride Paul

17th December 2002, 03:50 PM	#11 (permalink)
RoboPope GTR Register Member Join Date: Sep 2001 Location: Berkshire / Oxfordshire Posts: 477	yep, that'll do it

23rd December 2002, 05:09 PM	#12 (permalink)
swishboy GTR Register Member Join Date: Nov 2002 Location: cornwall Posts: 380	I think you need also a fuel cut defencer, this helps you raise the boost without detonation. Links up to the standard ecu. hks do one for about £100. hope that helps. swishboy

23rd December 2002, 05:16 PM	#13 (permalink)
swishboy GTR Register Member Join Date: Nov 2002 Location: cornwall Posts: 380	uk_skyman, I have the profec b boost controller setup on my r33gts-t and it will only get in to too much boost if i turn the boost controller on, and too high. Most of the time i have it turned off as the standard boost is limited to 0.7 bar, on stock ecu. I'm gonna get the hks fuel cut defencer fitted and i'm told with my hks head gasket, that i will be able to make 1.0 bar on standard turbo. Also i have found that to get really impressive boost i select the high end boost as low end just lose's traction P.s happy xmas skyliners swishboy

23rd December 2002, 07:12 PM	#15 (permalink)
RoboPope GTR Register Member Join Date: Sep 2001 Location: Berkshire / Oxfordshire Posts: 477	I dont have a standard ECU, injectors or AFM... plenty of scope to play there I think bring it on santa a very festive Paul

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