Help Reaching 400kw On Gt35r

[Jap_Muscle]

hey guys.

Currently own a 1999 r34 gtt which i have dropped a 26/30 into, ported/polished with all supporting mods. the car went in for its final tune after the build and was able to make 320rwkw on 16psi. a great effort i might add considering the previous setup (25/30) made similar power on 20psi.

unfortunately though my single plate isnt to happy with the amount of toqrue and power this baby is producing, so i have some spare time to locate a new twin plate.

while im looking for a new clutch i started reading the old "GT35r VS T04z" topic where many people have claimed 400rwkw on a gt35r .82 rear. which i have been ever so strongly trying to achieve.

the current setup is as followed

Ported/Polished RB26 Head

Forged Rb30 Bottom End

Garrett Gt35r .82 Turbo

Top Mount 6boost Manifold

Bosch Fuel Pump

OEM Cams

Jun Oil Pump + Collar

i think thats about it. can anyone clarify if i have enoguh supporting mods to join the 400kw club?

Cheers

[TiTAN]

What bosch fuel pump?

what injectors?

what fuel?

cam gears?

high or low compression engine?

what size exhaust?

stock coil packs?

[Jap_Muscle]

044 bosch fuel pump

1000 sard inj

bp 98 fuel

oem cam gears

i think the compression is 8:1

V-Band 3.5 straight pipe ceramic coated exhaust

splitfire coilpacks

Edited September 9, 2009 by Jap_Muscle

[N1GTR]

Cams?

Springs?

Valves?

Flow test on head?

Thats a very low compression ratio

[Jap_Muscle]

as stated in the first post im using OEM Cams.

not 100% sure on the specific of the porting and flow test ill have to get back to you.

as for the compression i cant rememebr if it was 8:1 or 9:1. should all theres be at a certain level ? how much should the head be flowing to make this sort of power?

i have PM'ed a few who have claimed to have reached this power but i never seem to hear back from them. i guess i can understand if everyone dosnt wanna share their secrets =[

Edited September 9, 2009 by Jap_Muscle

[DRIFTER]

i doubt you'll make 400 without cams and another fuel pump.

[R31Nismoid]

You don't have a set of cam gears on a 26 head? jebus... start there.

Next, could well again be the trusty old exhaust. 400rwkw = 4".

But then seeing as though you have not tried for near on 400rwkw, its a bit hard to say what will let you down without a crystal ball

[Jap_Muscle]

how big do you rkn i should go?

280 to big?

[R31Nismoid]

IMO it can be done without cams - others always disagree but very recently i was on the virge of going 26/30 and was assured without question stock cams would do 400rwkw... as they have done so before in a few cars

Results talk, and there are a few around, so its not a guess.

[Guilt-Toy]

i got 380 rwkw with stock cams with a 1.06 rear housing in a hydro rb25det head. the 26 head should get there if you ask me. especially seeing you are making 320rwkw on 16psi! that is a very healthy setup to get those numbers.

turn up the wick, give it a crack.

[FineLine]

I made 397 kw on a 25 with a .82 housing on pump 98. It took a fair bit of friggin around fine tuning everything to get it there but you should be able to do it n/p with a 3 litre bottom end.

head work and free flow was where we eventually found what we were looking for. Big cams are not neccessary. we are using gtr poncams in my engine.

Port match everything you can lay your hands on, it makes a difference. I am using a 3&1/2 inch exhaust system. I wouldnt reccomend anything smaller. 4 inch would make it easier.

We were stuck around the 350 kw mark for a while but in the end a better flowing exhaust manifold and an ecu change saw it make the number on only 24 lb of boost. More there if we want it but for me its plenty in a rwd.

[Fastrotor]

What exhaust manifold did you swap from and too fineline ?

Gary

[FineLine]

I had a 3 mil stainless job and we couldnt get the required result. Besides that it kept on cracking Gary.

Mik from signature performance offered to fab one for me that he guaranteed would flow way better than what was there.

Not quite as pretty as a 6 boost etc but certainly not ugly as far as mani's go. And...It works.

[N1GTR]

Fineline are you saying you went from a 6boost to the one Mik offered and increased flow? Or am i reading it wrong

Stock cams can do it, but its definatly a smart move to at least get some 2nd hand drop ins and use them

[FineLine]

Fineline are you saying you went from a 6boost to the one Mik offered and increased flow? Or am i reading it wrong

Stock cams can do it, but its definatly a smart move to at least get some 2nd hand drop ins and use them

Yeah you read It wrong Steve (or i wrote it wrong). I went from a 3 mil stainless to the one Mik made for me.

[Jap_Muscle]

I made 397 kw on a 25 with a .82 housing on pump 98. It took a fair bit of friggin around fine tuning everything to get it there but you should be able to do it n/p with a 3 litre bottom end.

head work and free flow was where we eventually found what we were looking for. Big cams are not neccessary. we are using gtr poncams in my engine.

Port match everything you can lay your hands on, it makes a difference. I am using a 3&1/2 inch exhaust system. I wouldnt reccomend anything smaller. 4 inch would make it easier.

We were stuck around the 350 kw mark for a while but in the end a better flowing exhaust manifold and an ecu change saw it make the number on only 24 lb of boost. More there if we want it but for me its plenty in a rwd.

so you made those figures on a 25 bottom end? thats pretty amazing fineline. how big are the poncams your using? hate to be a pain in the ass but do you mind publishing a spec list on your build with a dyno chart?

btw how do you compare your current manifold with the 6boost goods? i ended up purchasing one but thats all ive ever used.....all i hear is they are top quality but never really compared it to others myself.

thanks

Edited September 10, 2009 by Jap_Muscle

[FineLine]

Fair enough

How are you finding it? Have you by any chance had a flow test done against a 6 boost one?

I havnt had it flowed against anythingh else mate. It works, It hasnt given a moments trouble. I have had it on and off a few times there is no warpage. Its a damn good home grown product that does everything i ask of it.

[NYTSKY]

If the car is not your daily, then switch to E85. You will smash 400rwkw no dramas at all

[FineLine]

so you made those figures on a 25 bottom end? thats pretty amazing fineline. how big are the poncams your using? hate to be a pain in the ass but do you mind publishing a spec list on your build with a dyno chart?

btw how do you compare your current manifold with the 6boost goods? i ended up purchasing one but thats all ive ever used.....all i hear is they are top quality but never really compared it to others myself.

thanks

Why do you find it so amazing. For all intents and purposes the 25 is the same engine as the 26, Head design and flow is the same. Cubic capacity is so close as to be the same. The major difference is the 26 is solid lifter operation and the 25 is hydraulic. Its a simple enough process to convert the 25 head to solid lifters and lose the vct and presto, theres your 26 head. There are any number of 26's out there making these numbers. why such surprise that a 25 can do it as well.

As for a spec list. How much time do you have. I have left no tern unstoned in the build.

From the ground up, Hi energy gated baffled sump. All the usual mods to the crank inc snout, balance, chamfered gallerys etc. arp big end and main bolts. spool rods, ACL pistons. Jun oil pump. ARc catch can

Cylinder head ported to the hilt with squish chamber work, Over size valves, heavy valve springs, solid lifter operation. vct disconnect. Tomei cams. 9.15 lift, 260 degrees duration. Arp head studs, Oil restrictors, oil drain back.

Greddy Intake plenum, Tomei fuel rail, Sard 800cc injectors, 85 mil throttle body. Aero fpr, Surgetank with internal and external pumps, large front mount, Oil cooler and relocator.

Signature performance himount zorst manifold, Garret 35/40 turbo, shroud ported and window cut. Tial 44 mil wastegate, 3 and 1/2 inch zorst from the turbo to the tail.

T/B is port matched to the plenum is port matched to the head is port matched to the exhaust manifold is port matched to the turbo is port matched to the dump and so on down the line.

Haltech E11V2 ecu, Split fire coils are about to be swapped out for LS1 units.

Npc clutch, Rebuilt and cryo treated 25 gearbox, Hardy spicer custom tail shaft with oversize uni joints and so much more I get a headache thinking about it.

At 24 lb of boost the dyno spat out 533.5 hp.

I have a dyno graph in front of me but us old farts are not all that puda savvy so i cant post it up. Shane F did post it up in here somewhere so if you're that keen to view it do a search and it should turn up. Failing that drop on by and i'll make you a coffee while you look at the graph. Engine assembly was done by Dan at Elite racing developments, Engineering by chiltons and tuning by Signature performance. The solid lifter conversion was done by JHH engineering along with some of the headwork.

There are far wiser heads on these boards than mine but the one thing i have learned about forced induction is Flow. Get it to breath with lots of headwork and get it to flow with good port matching and the horsepower just tumbles out of these engines.

In other words, Spend as much on your cylinder head as you have on the rest of the engine. Therein lies the secret to fat power with torque to match. Gl with yours, i hope your journey is far smoother than mine has been.

[shanef]

That head with cam gears will get you your 400rwkw on ~25psi but with some poncams or 1 step up itd make the power curve alot nicer.

Why do you find it so amazing. For all intents and purposes the 25 is the same engine as the 26, Head design and flow is the same. Cubic capacity is so close as to be the same. The major difference is the 26 is solid lifter operation and the 25 is hydraulic. Its a simple enough process to convert the 25 head to solid lifters and lose the vct and presto, theres your 26 head. There are any number of 26's out there making these numbers. why such surprise that a 25 can do it as well.

As for a spec list. How much time do you have. I have left no tern unstoned in the build.

From the ground up, Hi energy gated baffled sump. All the usual mods to the crank inc snout, balance, chamfered gallerys etc. arp big end and main bolts. spool rods, ACL pistons. Jun oil pump. ARc catch can

Cylinder head ported to the hilt with squish chamber work, Over size valves, heavy valve springs, solid lifter operation. vct disconnect. Tomei cams. 9.15 lift, 260 degrees duration. Arp head studs, Oil restrictors, oil drain back.

Greddy Intake plenum, Tomei fuel rail, Sard 800cc injectors, 85 mil throttle body. Aero fpr, Surgetank with internal and external pumps, large front mount, Oil cooler and relocator.

Signature performance himount zorst manifold, Garret 35/40 turbo, shroud ported and window cut. Tial 44 mil wastegate, 3 and 1/2 inch zorst from the turbo to the tail.

T/B is port matched to the plenum is port matched to the head is port matched to the exhaust manifold is port matched to the turbo is port matched to the dump and so on down the line.

Haltech E11V2 ecu, Split fire coils are about to be swapped out for LS1 units.

Npc clutch, Rebuilt and cryo treated 25 gearbox, Hardy spicer custom tail shaft with oversize uni joints and so much more I get a headache thinking about it.

At 24 lb of boost the dyno spat out 533.5 hp.

I have a dyno graph in front of me but us old farts are not all that puda savvy so i cant post it up. Shane F did post it up in here somewhere so if you're that keen to view it do a search and it should turn up. Failing that drop on by and i'll make you a coffee while you look at the graph. Engine assembly was done by Dan at Elite racing developments, Engineering by chiltons and tuning by Signature performance. The solid lifter conversion was done by JHH engineering along with some of the headwork.

There are far wiser heads on these boards than mine but the one thing i have learned about forced induction is Flow. Get it to breath with lots of headwork and get it to flow with good port matching and the horsepower just tumbles out of these engines.

In other words, Spend as much on your cylinder head as you have on the rest of the engine. Therein lies the secret to fat power with torque to match. Gl with yours, i hope your journey is far smoother than mine has been.