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Discussion Starter #1
so why would the spec below not make more than 660 bhp? It's got everything I could possibly think of then some. In my opinion which is not too techy I believe it should make 700+ ? It's running quite rich which is better than lean for obvious reasons and the larger injectors could leave excess fuel if it was driven for just short runs. On mapping however this spec should make more power IMO ....
Torque is only at about 530lbs which my r33 was when running -5's and 600bhp.

What do the people in the know reckon?

ENGINE

CAPACITY RB 2.8 striker kit
Cylinder bore 86.5mm
Cosworth forged pistons
Pec rods (new )
Acl race bearings
New N1 block
Nismo oil pump
N1 water pump
Head drain into sump
New metal gasket
Tomei 264 in cam
Tomei 272 ex cam
Inlet/exhaust port and polish
Expanded ports
Ngk plugs
Full silicone hose kit
Polished fuse cover
Sumo power damper
Rk extended sump
Rk baffles

TURBO AND EXHAUST

TO4z turbo kit
Custom 4" stainless center section
Custom 4" rear section
4.5" stainless tip

INTAKE
JUN plenum
Hks huge triple core intercooler
Custom intercooler hard pipe kit

FUEL SYSTEM

SARD 850 cc injectors
Sard racing fuel rail
Twin intake fuel pumps
Twin Bosch pumps
Big swirl pot
New braided hoses

COOLING SYSTEM

Freddy large capacity racing radiator
Nismo radiator cap
N1 water pump

DRIVE TRAIN

Os 1-4 gear kit
Hks triple plate clutch
LSD rear diff

Suspension/brakes

Bilstein bespoke coil overs
Pillow-ball adjustable tension rods
Twin front adjustable camber arms
Nismo rear upper arm (front and rear)
Nismo rear lower arms
Hicas cancel rod
Hubcentric 25mm rear wheel spacer
Hks kansai front strut brace
Cisco rear strut brace
Ap racing big brake conversion
Ferodo ds2500 pads all round
Braided stainless brake lines
Uprated master cylinder
Cusco master cylinder stopper

ELECTRONICS
HKS F-con v pro gold 2 ecu
Freddy profec b boost controller
 

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The fuel and engine set up look good for the power, provided that they are in good working order / the work has actually been done.

What is the power range of the to4z? Does it have optional size covers? And who has done the tuning?
 

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Bring her down to Surrey Rolling Road next saturday (see meets section) and you can run it with a load of other gtr's. That way you can compare, same day, same rollers.

Your 33 may only have made say 550bhp on the dyno your 32 was on, or different calc for flywheel losses etc
 

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Discussion Starter #6
I believe everything is there as stated, perhaps the coil packs, injectors or similar are bot operating correctly.
I know the car feels no more powerful than my R33 so wouldnt bother with a rolling road day to be honest. The car seems very rich and kicks out a bit of black smoke now and again also.

I'll pop up the graph Monday see what you think
 

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I think the t04z would be similar to my gt40, exhaust housing size can play a huge roll, I made 552 whp with a 0.84 a/r housing 1.5 bar, then made 655 whp with a 1.06 ar housing at 1.5 bar !

and that was backed up with my 30 - 130 mph time dropping by 1.1 seconds to 9.76, and 1/4 mile terminal speed went from 123 mph upto 129 mph.
 

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I would say you are in the ball park for a To4z depending on exhaust housing size etc.
As above, you haven't stated your exhaust housing size, which will help in determining approx final hp/BHP figures.

For a hks 0.84/0.86 ex housing (forget which one it is) your in the right zone.
 

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Discussion Starter #10
Ok well sounds comforting. I assumed this would be a 0.99 ? Is that right or am i making jt up that this is one of the three sizes?

Also obviously it was advertised as a 700+ car and ive seen other state these types of figures with similar or lesser set up.
It was dropping off at 620 ish before as well then changed a spring and that helped.

Scooby slayer what torque figures have you got? And is your turbo similar to to4z?

I guess finding out for fact, what housing size i'm running is my main objective now then!
 

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Ok well sounds comforting. I assumed this would be a 0.99 ? Is that right or am i making jt up that this is one of the three sizes?

Also obviously it was advertised as a 700+ car and ive seen other state these types of figures with similar or lesser set up.
It was dropping off at 620 ish before as well then changed a spring and that helped.

Scooby slayer what torque figures have you got? And is your turbo similar to to4z?

I guess finding out for fact, what housing size i'm running is my main objective now then!

my torque figure is 500 lb/ft at all hubs, but my motor is low comp im sure, and it revs to 8700 rpm :chuckle:

I bought my car as a 700 hp car but in reality it was about 550 hp 30 - 130 was a measly 12 seconds which is nowhere near 700 hp :bawling:
after fixing several issues and retuneing twice its now upto 720 hp 30 - 130 in 9.76 seconds and im happy with it goes very well considering its an old gt40.

I would say your to4z and my gt4094r are very similar, my gt40 is rated to 80 lb/min max whats the to4z rated to ?

turbine size will make a big difference to top end power, I gained some off boost power aswell with the bigger housing that is clearly visible on the dyno plots but more importantly I can feel the difference when cruising in 5th at 70 mph it has enough grunt to just pull away steadily like a normal car would without downchangeing :)
it now makes 2 or 3 psi even as low as 2500 rpm which is enough to give it that little kick to make it very streetable

and my motor when comp tested only shows 138 psi across the board on 260d cams so defo a low comp motor imo.
 

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Discussion Starter #12
Looking into it, there seems to be varying info. It's supposed to be rated to 75lb/min and most definitely over 700hp even upto 850 ish with a squeeze of nos! With that, a lot of figures from other users are quoting around 630 lbs torque, which is more what I'm interested in.

The smallest housing is only recommended for 2litre engines. The .83 for 2.5 litre engines and 1.00 for around 3 litre lumps. I should only have one of the larger housings and should definitely make much more power and torque.

Your figures are very good!


my torque figure is 500 lb/ft at all hubs, but my motor is low comp im sure, and it revs to 8700 rpm :chuckle:

I bought my car as a 700 hp car but in reality it was about 550 hp 30 - 130 was a measly 12 seconds which is nowhere near 700 hp :bawling:
after fixing several issues and retuneing twice its now upto 720 hp 30 - 130 in 9.76 seconds and im happy with it goes very well considering its an old gt40.

I would say your to4z and my gt4094r are very similar, my gt40 is rated to 80 lb/min max whats the to4z rated to ?

turbine size will make a big difference to top end power, I gained some off boost power aswell with the bigger housing that is clearly visible on the dyno plots but more importantly I can feel the difference when cruising in 5th at 70 mph it has enough grunt to just pull away steadily like a normal car would without downchangeing :)
it now makes 2 or 3 psi even as low as 2500 rpm which is enough to give it that little kick to make it very streetable

and my motor when comp tested only shows 138 psi across the board on 260d cams so defo a low comp motor imo.
 

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Ditch the t04z and buy something bigger your on the limit of the to4z I've not seen one make more than 700bhp. You could sell the to4z and buy a bigger precision,garrett gtx or borg warner efr and make a lot more power and make full boost at the same rpm.
 

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Ditch the t04z and buy something bigger your on the limit of the to4z I've not seen one make more than 700bhp. You could sell the to4z and buy a bigger precision,garrett gtx or borg warner efr and make a lot more power and make full boost at the same rpm.
I agree,if you want to tune properly then the turbo should be in its maximum efficiency zone at full power, not anywhere near its maximum airflow, you need to select a correctly sized intake housing using compressor maps otherwise your turbo will require more exhaust energy to produce the required airflow. This will cause higher back pressure and limit power, giving the impression of a smaller exhaust housing.
Larger AR exhaust housings will help produce more power as they reduce back pressure, but the turbo will still require the same power to pump the air unless you improve the compressor efficiency.
It may help to see changing the AR as a way to 'gear' to turbo to the engine, rather than it being to do with engine size as this is a common mistake.
 
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