Help Reaching 400kw On Gt35r

[FineLine]

Thanks for sharing Fineline, appreciated.

So how much ballpark for JHH to do your porting and lifter conversion. I see you didnt go for a huge cam, so was it necessary to go solid lifters ?

Gary

The actual solid conversion only cost about 600 dollars from memory Gary.

My cam selection was based on the type of power delivery I was looking for. Pon cams are not big but they are bigger than anything I could get in the 25 hydraulic lifter set up.

port work depends on how deep your pockets are. I was fortunate in that the original head I purchased had 80% of the porting and chamber work already done. JHH touched up the inlet side When they fitted the o/s valves springs etc.

The head still wasnt where we wanted it as far as the exhaust side went so I gave it to Mik at signature and he weaved his magic on it. He has dossiers as thick as encyclopedias on eons of intensive porting and flowbench work on RB heads, I am not at liberty to give away too much but suffice to say the head flows beautifully.

Our cam timing is a little different to what some may consider the norm but the results speak for themselves. I see my first lb of boost at only 1600 rpm and it just hoses hard all the way to 8 kay. Whilst I am pleased with the end power figure it is secondary to the power delivery This engine dishes out. That was my primary goal right from the getgo and it has delivered in spades.

Given my time over I could do it in half the time and half the cost. There was so much trial and error involved. The first engine did over 350 power runs on the dyno mainly due to my own stubbornness in refusing to believe some of my ideas wouldnt work. Dan built that engine as well, It was a gem but alas it came to grief when the clutch nuked and ripped it apart.

Best tip I can give anybody wanting to do this sort of thing is simply, Do not take one shorcut. Not one. These boosted engines have a way of seeking out the weakest link and destroying it, Usually taking other compenents along for the ride.

[discopotato03]

Hi Fine Line , thats my theory as well with my RB25 - so much tied up in the head . My modified head isn't on yet and it has OS exhaust valves as in larger but not enough to need the seats to be changed . For cost reasons I stayed hydraulic and got R33 RB25 poncams for it . With skimming the CR should rise to a bit over 9:1 .

The exhaust manifold I'm thinking of running is the cast HKS one and hanging a GT3076R off that . My goal is to have a very streetable 280+ Kw and if keen enough may get RIPS modded lower inlet manifold and mount RB26 multi throttles on it for snappy throttle response .

It's the torque and response I'd like in a reasonably free reving RB25 .

Cheers A .

[FineLine]

9k on a real good head is not over the top for the right engine, we spend alot more than that to build our top of the line heads and I can confirm big power comes pretty easy with the right headwork and everything else "just right".

nzd60-80k is pretty easy to spend on a real nice complete 1000-1400hp+hp RB30 with all the good gear.

Rob

We.re not trying to run 7 second passes ripmeister. responsive strteet/track car is where its at for me. but yeah, I have spent a good deal on head work and flow. It makes sense to make the power i want without having to turn the boost wick up any more than i want to.

[rb30_22]

mabye you should try porting the heads and using a bigger cam to aheive 400 kw at higher boost levels, or if u upgrade to a bigger turbo

[Jap_Muscle]

well the intake side was match ported to the runners and exhaust side has been ported and polised. im still running standard cams but plan to get something bigger when the cash flow is a bit better.

Valve springs and valves are still stock but that should be fine unless im going for 1000+hp right?

[shanef]

you'll more than likely encounter valve float with the std springs. get some aftermarket springs put in when u get the cams (some psi springs should be fine, about 300)

[Jap_Muscle]

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.

im currently just running the standard GTR plenum. im not sure how big these things are but im pretty certain ill have to be upgrading this aswell along with the TB.

exactly how big have you match ported everything FineLine?

any thoughts?

you'll more than likely encounter valve float with the std springs. get some aftermarket springs put in when u get the cams (some psi springs should be fine, about 300)

thanks for the tip shanef......its like someone else on SAU said....theres always something stopping me lol

Edited October 12, 2009 by Jap_Muscle

[shanef]

im currently just running the standard GTR plenum. im not sure how big these things are but im pretty certain ill have to be upgrading this aswell along with the TB.

exactly how big have you match ported everything FineLine?

any thoughts?

thanks for the tip shanef......its like someone else on SAU said....theres always something stopping me lol

with fineline's setup (i've spannered on it many a time ) the plenum and manifold are matched to the size of the ports in the head. his head having been ported by a cylinder head shop, is very different to the std or even a 'rough hand make the ports bigger job', so just port match them to the shape of the ports in the head.

[Jap_Muscle]

with fineline's setup (i've spannered on it many a time ) the plenum and manifold are matched to the size of the ports in the head. his head having been ported by a cylinder head shop, is very different to the std or even a 'rough hand make the ports bigger job', so just port match them to the shape of the ports in the head.

would it be fair to say it be cheaper just buying a aftermarket plenum? or having one custom made by Hypertune to the port sizes?

[shanef]

ur misunderstanding it...

any manifold you buy, even the std one, wont have the same shape in the port where it bolts to the head. By making the plenum (or manifold) port the same shape as the port in the head, this is called 'port matching'.

You wont need a new plenum for your goal.

[msnismo]

Gotta say that valve springs are a good investment.. valve float is going to be the killer.. Agreed with Shane

I made more power on my built 25 (still has the 25 bottom end) with poncams (baby type A's) and Type A springs than dave made on his built 26 with same poncam equivalent and standard springs!! This was on the T04Z thought not the GT35R... same turbo two different cars, and same engine builder! - I stole his turbo whilst he wasn't looking Annnd my fuel setup isn't as sorted as his.

He got to 376rwkw before no matter how much boost they dialled in, it just wouldn't make any more power due to the valve float.

My Gt35r only had the 0.63 rear and the exhaust was 3" with a metalcat and one muffler - but this ended up being the restriction and I couldn't get past 350rwkw... not sure if the smaller rear had anymore in it though??? This was on 21-22psi too...

Can't see why it wouldn't get to near 400rwkw on pump with the right setup

[Jap_Muscle]

interesting....i might just have to invest in some valve springs then.

how much do they go for these days? does SAU have any traders who sell? recommended brand type or seller at all?

btw msnismo, what sort of cam system are you running?

edit::

what is the difference in Type A B and C valve springs? are they similar like Cams where power is made at different points throughout the rev range?

sorry guys im a complete freshmen when it comes to engines.

Edited October 12, 2009 by Jap_Muscle

[msnismo]

interesting....i might just have to invest in some valve springs then.

how much do they go for these days? does SAU have any traders who sell? recommended brand type or seller at all?

btw msnismo, what sort of cam system are you running?

Just tomei 256 in/ex... smallest ones out! I didn't want to go solid lifters as I wanted my car back by that stage! Dave did do a little porting on the head/valves etc but not a great deal. The springs are just tomei Type A's... I picked mine up a while ago for $450 odd new.

And no cam gears... I was told the poncams run best on standard as that is how they are designed and tested.

Edit:

Type A cams need type A springs for optimum result or can use standard to a certain point (a drop in replacement, no mods needed)

Type B cams need type B springs for optimum result

etc etc... Some I think you have to run the springs, once you get to a certain level then its lifters and everything - well on a 25 head anyways!

[Jap_Muscle]

how much power did you make with the gt35r msnismo? did you just simply swap the turbos or did you do other mods? also what rear housing did you use on the 35r?

i know with a t05z 400kw isnt a big strech at all and it is able to make that sort of power without all the added strings attached. alot of VLs, Skylines and among other cars are pushing 400+ kw out of a .86 gt35r.....and i would much like to do the same before i step up to something bigger.

i just wish i knew wat was missing. i do however have added valve springs to the list of things to do.

as it stands now....some cams/cam gears, valve springs, and 25+psi should be a good place to start.

as i mentioned before the car is currently sitting at 330kw on 16psi which is a great effort i guess, but the turbo is no where near its efficiency range.

a small snapshot of the progress thus far. it does need a good polish though

Edited October 12, 2009 by Jap_Muscle

[msnismo]

GT35R - 0.63 rear - exhaust was 3" - 6 boost manifold

The dyno sheet is in my post - 345rwkw.. it wanted to make more power but the exhaust said NO... changed turbos as the T04Z power delivery is much more fun annnnnd it was just lying around

By Comparison, I had 330rwkw at 15psi on my GT35R....

T04Z is 0.84 rear - exhaust 3.5" and cat free - more in the turbo, just not my fuel set up!

EDIT - Sorry only change between turbos was - larger exhaust and more free flowing, and a custom 1" steampipe manifold to avoid some lag (similar to my old 6 boost) . .... rest of setup remained exactly the same

[R31Nismoid]

You don't need bigger than a GTR plenum for 400rwkw.

There are plenty of cars from Racepace that have all gone 380-400rwkw without altering anything from factory plenum/intake wise.

They all run factory cam's are well incidentally.

[DRIFTER]

GT35R - 0.63 rear - exhaust was 3" - 6 boost manifold

The dyno sheet is in my post - 345rwkw.. it wanted to make more power but the exhaust said NO... changed turbos as the T04Z power delivery is much more fun annnnnd it was just lying around

By Comparison, I had 330rwkw at 15psi on my GT35R....

T04Z is 0.84 rear - exhaust 3.5" and cat free - more in the turbo, just not my fuel set up!

EDIT - Sorry only change between turbos was - larger exhaust and more free flowing, and a custom 1" steampipe manifold to avoid some lag (similar to my old 6 boost) . .... rest of setup remained exactly the same

my rb26, gt35r, 1 inch 6boost manifold, .82 rear housing, 3 inch exhaust, standard cams and springs set-up makes 330rwkw on 23psi, thought i was the only one with that manifold, guess not.

[N1GTR]

Have you seen any more power Nathan from more boost?

Surely valve float isnt too far off

[SirRacer]

how do you guys control boost with those sort of setups? wastegate mounted off the exhaust housing?

i changed from a .82 to 1.06 (havent yet retuned) and added a bigger gate (44 to 48mm) and it started to boost creep madly from there.

[Jap_Muscle]

i had a similar problem.

the rb30 along with a 6boost manifold was just flowing so much air that the 44mm gate wasnt expelling the air fast enough to control boost. had the 6boost manifold modified to fit a 60mm gate.

that dosnt just mean slapping on a 60mm gate. you have to make sure the pipe that leads to the 60mm gate is 60mm aswell. havnt tried anything smaller but the 60mm fixed my issues.

i had the .82 rear