R33 Rb30 Conversion

[MarkE]

Thoughts on peformance of a GT30R with .63 exhaust housing as compared to a GT3540R with .82 exhaust housing on a stock RB25DE head, on a stock RB30E (8.3:1 comp)?

How quickly it would be on boost in terms of driving on the street, and peak power figures on the dyno?

I'm seeing guys like Sky30 with his GT3540 making over 300RWKW with a relatively stock engine with the GT3540, but what would it be spooling up like in first, second, and third gears as compared to 4th on the dyno ... ?

Edited December 5, 2005 by MarkE

[Cubes]

No idea..

According to garrets catalogue and turbine maps the GT35R .82 flows the same as a GT30R 1.06. or GT35R .64 the same as a GT30R .82.

Sky30's GT3540 .82 has 19-20psi boost in by ~3500rpm.

I'm going to go with a .7 or .82 GT3040. I'm not after mega power just street usable power. upwards of 280rwkw I'll be happy.

[sky30]

Thoughts on peformance of a GT30R with .63 exhaust housing as compared to a GT3540R with .82 exhaust housing on a stock RB25DE head, on a stock RB30E (8.3:1 comp)?

How quickly it would be on boost in terms of driving on the street, and peak power figures on the dyno?

I'm seeing guys like Sky30 with his GT3540 making over 300RWKW with a relatively stock engine with the GT3540, but what would it be spooling up like in first, second, and third gears as compared to 4th on the dyno ... ?

<{POST_SNAPBACK}>

My GT35/40 on the street starts making some boost at about 2800rpm, Full boost is between 32000-3600RPM depending on which gear.

4th and 5th gear will make full boost at 3200-3400RPM, 1st and 2nd gears are too hard to tell (Wheelspin, revs too quick).

3rd gear (with NEW tyres otherwise it wheelspins aswell) has a little less load on the engine and makes full boost at 3400-3600RPM.

[MarkE]

I'm going to go with a .7 or .82 GT3040. I'm not after mega power just street usable power. upwards of 280rwkw I'll be happy.

<{POST_SNAPBACK}>

Thats what Im after, and why Im considering the .63 GT30R.

After some emailing, Ive been put in contact with an American guy selling:

GT30R  .63 A/R : $1050

GT3540R  .82 A/R:  $1100

Plus: Shipping is $90 to AU

Tial Wastegates:  38mm ($200 - gate only), and 44mm complete kit ($350)

~$1524 AUD for the GT30R, and ~$1591 for the GT3540R.

Roguepi on Ebay has GT30Rs for $1699 AUD, and GT3540Rs for $1749:

http://cgi.ebay.com.au/GT30R-500-hp-BB-GAR...1QQcmdZViewItem

[Cubes]

The RB30 really needs a nice free flowing hotside OTHERWISE you start loosing out of rev's and it turns in to a diesel type motor.

A .63 GT30R would be too small. Look at a .63 GT35r at least or a GT3040 .82.

[MarkE]

What about a GT3071R for something IW?

With .82 housing possible to make ~275RWKW ?

[Craved]

you thinking of selling the Poncams ?

<{POST_SNAPBACK}>

my car still has the rb25, so i'll be running it with the cams in it til the rb30/25 is done..

was thinking of selling them, thats why i asked the questions about the cams.

if longer duration cams would be better then i would get them, just a pain that i just bought the poncams, and havent even run the car with them in..

see how it goes.

[discopotato03]

Go with what makes you happy but remember the Garrett GT3040R (56T only) will have the exhaust restriction of a GT30R and a slight lack of turbine power to drive an 82mm GT40R compressor . HKS speced their 3040 with a 50 trim compressor because they knew the size mismatch was not ideal . I'd rather use a larger turbine housing on a GT30R (the real GT30R) . Many are finding that cutting down on the turbine inlet pressure uncorks the exhaust side with noticeable benefits . A good example is the VG30 housing on the RB25 turbos or Hi flows . Some of the American turbo mobs tend to agree that limiting a turbo by compressor flow rather than turbine flow works out well as is less damaging to the engine .

Cheers A .

Edited December 5, 2005 by discopotato03

[R32GTST]

I have finally finished reading all these pages and am about to embark on this build. I have a couple of questions for those who have already built. Which type of piston would be the best suited to give around 9:1 or is it easier to stick with rb30e pistons? which harmonic balancer would be the best to use an rb25 or rb30? everything else i have sussed just these last two. Any other pitfalls i should watch for? I have an R32 RB25 non vct head HKS 264 cams from my previous rb20 i have an rb30 bottom end on the way which supposedly has rods in it. I plan to run a garret TO4Z with a 1.06 rear and gtr intake plenum and throttles which are just about ready to bolt on the 25 head. Any input is greatly appreciated.

[conan7772]

I have finally finished reading all these pages and am about to embark on this build. I have a couple of questions for those who have already built. Which type of piston would be the best suited to give around 9:1 or is it easier to stick with rb30e pistons? which harmonic balancer would be the best to use an rb25 or rb30? everything else i have sussed just these last two. Any other pitfalls i should watch for? I have an R32 RB25 non vct head HKS 264 cams from my previous rb20 i have an rb30 bottom end on the way which supposedly has rods in it. I plan to run a garret TO4Z with a 1.06 rear and gtr intake plenum and throttles which are just about ready to bolt on the 25 head. Any input is greatly appreciated.

<{POST_SNAPBACK}>

No way I'd stick with stock pistons in a rebuild like this.

I'm going forged pistons,rings and rods, N1 oil & water pumps,

Oil squirters fitted in the RB30 block.

No bloody way I'm gonna be standing outside Goulburn at 2 a.m. on a Sunday night waiting for a tow again...

Later on, after she's run in, I'll do my head and bigger turbo.

I hoping to get high mileage with this engine

[Bl4cK32]

I hoping to get high mileage with this engine

<{POST_SNAPBACK}>

Then why are u building it like a race motor?

Forged rods etc are not needed if you want reliability. Its all about tuning and what you do with the motor.

Also you shouldnt need oil squirters if you are running the forged pistons.

R32GTST - The harmonic balancer from the rb30 and the rb25 are different, due to the fact they run different aircon belts (the middle belt on the pulley from memory) Run whichever one you are going to put the car in (to use its aircon) the rb30e one has a v groove belt, as the rb25 has the same belt as the alternator, and ps.

Those 264 cams would be great

[R32GTST]

I am planning on using forged pistons just trying to decide which ones to use. I thought thr rb30 harmonic from a R31 skyline run all ribbed belts it was the VL that had the single belt. Im more concerned with which one is more up to the task ie is one better than the other or I guess I just have to fork out for an ATI dampener.

[Cubes]

ATI damper = ~900 or so .

Don't get carried away with the build, too much power will go up in tyre smoke, the car will be dissapointing to drive due to lack of traction even with a set of wide semi's.

By the looks of it expect to spend ~8-9k on the build.

Don't forget to fit the cranks oil pump drive collar.

How much power do you intend to push with the TO4Z?

Sell the GTST grab a GTS4 or GTR and bolt the motor in that. Much more useable.

Its nice to dream and get carried away with the build up, I did slightly and wish I had not as forged pistons is not needed for 300rwkw, headwork was not needed and would have been better spent on a set of cams and springs.

Edited December 7, 2005 by Cubes

[discopotato03]

The RB 26 Inlet manifold won't bolt to the R32 RB25 head , RB26 head is different on both sides to the other RB twin cam heads and more trouble than its worth to graft its manifold onto the 25 head . 26 head is the go if you can get one , all you have to worry about then is the stud pattern being wrong for RB20/25 single turbo exhaust manifolds . I'd like to strangle HKS for not making the manifold to suit the RB20/25 and 26 pattern as the 26 cast version is very hard to get .

Cheers A .

[MarkE]

Thoughts on the XR6 internally wastegated 3540? 1.06 housing is huge, but how much would you be looking at to throw a .82 housing on it?

[R32GTST]

The RB 26 Inlet manifold won't bolt to the R32 RB25 head , RB26 head is different on both sides to the other RB twin cam heads and more trouble than its worth to graft its manifold onto the 25 head . 26 head is the go if you can get one , all you have to worry about then is the stud pattern being wrong for RB20/25 single turbo exhaust manifolds . I'd like to strangle HKS for not making the manifold to suit  the RB20/25 and 26 pattern as the 26 cast version is very hard to get .

Cheers  A .

<{POST_SNAPBACK}>

I have moded the rb25 runners to accept the throttles and plenum basically used the last 2 inches of runners where the injectors are. ( its easy when mates own machine shops) Took about half a day to get it all on and done.

[Looney_Head]

Loony Head,

I can answer.

The answers are in the guide, we used the same measurements for lowering the motor. Off the top of my head I can't remember.

There is no clearance issues with std ic piping.

With regards to how close to the cross member.. It sits closer by how much its lowered by.

Try not to think to much.. Its all very easy. Simply lower the motor, bolt everything up, extend the dump pipe height a little to meet the extra height.. Thats all that needs to be modified, everything bolts up perfectly.

<{POST_SNAPBACK}>

thanks cubes i was reading the guide and it didn't say how close the sump got the the cross memeber and was just checking, cause the sump sits in line with the cross member at the moment with the rb20 in there and i didn't want to worry about losing the sump if i hit a bump once the rb30 went in

[Cubes]

Its interesting you say the sump sits in line with the rb20 in there.

Mine sat slightly higher and it even had a broken torque (passenger) side engine mount.

I replaced the engine mount when the rb30 went in and the sump sits perfectly level with the crossmember.

Generally if you hit something that is high enough to hit the sump the cross member won't save it.

Years ago in my first car I hit a rock on a dirt road, it smashed my sump right at the front, the cross member didn't save it.

I also mounted a rather large gutter, once again smacking the front of the sump, the cross member didn't save it then either.

Either way it sits pretty much perfectly level with the cross member.

Edited December 7, 2005 by Cubes

[Skyrine-Dave]

since this thread gets more views than anything else...

can RB20 cams be placed into an RB25DET head without any dramas? I wanna get rid of the variable inlet cam and put my HKS inlet cam on it

[conan7772]

Then why are u building it like a race motor?

Forged rods etc are not needed if you want reliability. Its all about tuning and what you do with the motor.

Also you shouldnt need oil squirters if you are running the forged pistons.

Oil squirters couldn't happen. Not enough wall thickness.

Previously I cracked the top of a stock piston in the RB25DET, and threw the rod into a water galley.

I don't want this to happen again.

You know what women are like, I'll never hear the F______ end of it.

I just want a car that I can cane from time to time, bring it home and do it again tomorrow.

Also considering Open days at Wakefield park next year.

So starting from the bottom up, I thought this would be the way to go...

Edited December 10, 2005 by conan7772