1972 240z Rb30det Ground Up Rebuild

[sooley]

If you dont want it coming on all of a sudden,whatever you do,DONT put a .83 exh GT35R on.They are very snappy on on a rb30det.I think the 35R 1.06 exh would be perfect for what you want.The power is quite linear for the size of the turbo and can make good power.Anything over 500rwhp is just going to make it more difficult to drive.I have enough trouble keeping mine straight down a drag strip.I cant imagine trying to go around a corner on the accelerator with that sort of power in a zed.Thats just my opinion anyway.

 

Thanks for the info. I am concerned about the power and keeping the car under control. I think from memory I am running the 3.9 R200 LSD, but it might be the 4.1. I will have to check as I havent really looked at the Zed in over 4 years since I have spent all my time on doing up a house.

I am not a power freak, looking for the best dyno figures like some do. I just want it to be fast, if that means making less power to have more control, then thats fine with me.

 

What other tips do you have when running the RB30. What size tyres are you running as this may help me with traction if I go a bigger size.

 

Anthony

[240Z_Master]

 

What other tips do you have when running the RB30. What size tyres are you running as this may help me with traction if I go a bigger size.

 

Anthony

 

Big as you can

[sooley]

This is the turbo that I was thinking of

 

 

• Garrett GT30/40R Internally Wastegated Turbocharger
  
• Ball Bearing.
  
• Watercooled.
  
• Turbine Housing: 1.06a/r.
  
• Compressor Housing: 0.70a/r.
  
• Internally Wastegated.
  
• Rated: 600hp.
  
• Flange: T3

[240Z_Master]

This is the turbo that I was thinking of

 

 

• Garrett GT30/40R Internally Wastegated Turbocharger
  
• Ball Bearing.
  
• Watercooled.
  
• Turbine Housing: 1.06a/r.
  
• Compressor Housing: 0.70a/r.
  
• Internally Wastegated.
  
• Rated: 600hp.
  
• Flange: T3

 

You're going to want to stay away from the internal gates at 400+ WHP.

The largest turbo I would go with an internal gate may be a GT3071R but the GT3076R's and up I would suggest external.

[rbs30]

Thanks for the info. I am concerned about the power and keeping the car under control. I think from memory I am running the 3.9 R200 LSD, but it might be the 4.1. I will have to check as I havent really looked at the Zed in over 4 years since I have spent all my time on doing up a house.

I am not a power freak, looking for the best dyno figures like some do. I just want it to be fast, if that means making less power to have more control, then thats fine with me.

 

What other tips do you have when running the RB30. What size tyres are you running as this may help me with traction if I go a bigger size.

 

Anthony

 

 

Yeah.As 240z master said.As big as you can.I had 235 azensi's on it and i had mine de-tuned for daily driving down to a bit under 400rwhp and even at that power there are a lot of traction issues.Its all about the torque of the rb30.Mine is getting painted as we speak and while it is there they are lipping the arches as much as possible,so hopefully i'll be able to get some decent size m/t streets or nitto's etc.

If you want to have a look at mine in a few weeks when it is done being painted,im just up in newcastle.

[Z24O]

hi guys

couple of comments/observations/questions

 

sooley,there is a knowledgable guy on the skyline forum called discopotato03,his real name is adrian,i PM'd him some time ago seeking advice on turbo selection for my RB30ET....he didn't reckon the GT3040 was a well matched turbo for my application(PM me if you want to know more.....don't want to post his ideas that he PM'd me...or you could try contacting him direct,as 1000's of others do...may have to "take a number")

 

rbs30....thanks for the PM today,i'll wait for the pics mate,i am at the crossroads of an upgrade for my RB30ET/240Z and have read reams on the RB25 head on the RB30 block.....was really impressed with the torque figures,but now i am wondering if i would be better just upgrading the sohc head(porting,cam) as i have custom in/ex manifolds ready to go

no point building up a torque monster then working out i can't get it to the pavement....what do you reckon you'd do in my shoes?

 

there is no doubt that the smaller GT turbos will produce lots of HP(400-500hp),however this is likely to be on mega boost and at the expense of engine longevity.the bigger GT's eg 35R will produce the same HP at less boost psi

 

i think i will try and match the turbo size to 2 factors

1)maximum hp figure.....compressor size

2)maximun traction.......turbine housing size(auto trans/high stall will help too)

 

i was leaning towards a GT3076 with the 1.06 turbine a/r external gate

or the GT35 (.70 compressor housing)with an internally gated .82 a/r....may even consider the XR6 turbo,GT35 with 0.5 a/r comp and 1.06 IWG turbine housing

 

sooley ,sorry about the semi-hijacked thread,love the car,who did your cage,is it legal over east? only 1/2 cage allowed in perth

[rbs30]

Well if you already have all the gear for the sohc go for it.There are guys running 8 sec et's with sohc rb30's in commodores so why not.If you put a 25 head on you need to use a front facing plenum (greddy style) because the standard one doesnt clear the bonnet (hood for all the U.S. guys).I dont think the sohc has the same issue.It will still be a torque monster.

With turbo selection,It is my opinion that a bigger exh a/r is better (xr6t turbo would be great).On the skyline forums they call the GT35R .82 a "hair trigger" turbo because the difference between no boost and full boost is a couple of hundred rpm.This causes a lot of wheelspin.I have a 1.06 on mine and i had it on the dyno for hours tuning the E-boost to bring on the boost curve slower to help a little bit with the traction,and it did help.Thats my opinion anyway.

[Z24O]

rbs30,

when do you start seeing boost,what rpm is full boost in by?

how many psi are you running max?

you running in/ex wastegate....size?

what psi have you needed to restrict the boost to in the first 2 gears?

[rbs30]

rbs30,

when do you start seeing boost,what rpm is full boost in by?

how many psi are you running max?

you running in/ex wastegate....size?

what psi have you needed to restrict the boost to in the first 2 gears?

 

I see some boost by 2800 and full boost by 3800.Rev limit is 7500.It is fairly quick to get onto boost as im running 8.3 cr (standard rb30e pistons) so its still got the torque of a n/a 3 liter.

It made 546rwhp on 15psi so i havnt felt the need to go any higher than that(the turbo is also out of flow)

Im running a tial 40mm external gate.

I was going 12,13,15,15 psi but now it goes 13,14,15,15 but with a slower boost curve.

[neo240]

how wide are those boots on the back they fit nicely in the gards i love those simmons wheels

[rbs30]

One thing i forgot tm mention to sooley.If you are going to run a GT35R,you will have to make a custom exhaust manifold so as to mount the turbo forward or backward of the strut tower.I had a "off the shelf" stainless one and the turbo is around 1.5 inches higher than the hood.I had a scoop on it but im in the process of making a custom steampipe manifold.It cant be lowered either because the turbo wont fit between the engine and the tower with enough clearance.This is mine with the old stainless manifold on it..

[klh6686]

i would go with a precision pt61r for response or pt67r (similar to t04z) for a little more power. since you're at 3.0l I would look around at what supra's are running. moreboost.org has some graphs up to give you some ideas, and then there's always supraforums.com.

[jdizzy204]

what is it that ive been hearing about rb30s having something wrong with them that causes the crank to come apart over 7000 rpms???

[rbs30]

what is it that ive been hearing about rb30s having something wrong with them that causes the crank to come apart over 7000 rpms???

 

There are supposed to be some harmonics issues above 7000 rpm but i havnt had a problem.the crack is nitrided from the factory and the bore/stroke is exactly the same as a 2jz so i dont know what the problem is.i wouldnt take one above 7500 with a standard crank and rods though.

[jdizzy204]

well what if im planning on going with forged rods/pistons/harmonic balancer/balanced crank etc from the get go? would i still have to worry about a max revving point of 7000 rpm or so??

[rbs30]

No.Plenty of rb30s are revving past 8k.

[mannyvig]

Instead of worrying about how high you can push it, just build it so your power peak is just before 7500. This way you have nothing to worry about

[Careless]

what is it that ive been hearing about rb30s having something wrong with them that causes the crank to come apart over 7000 rpms???

 

that's not a characteristic of the engine itself. it is a quality that is inherent with all engines that are 20+ years old.

 

you gotta understand that RB30's are just about that old, and to build an RB30 that can whitstand prolonged abuse, you would have to build it with parts comprised of a mish-mash of items from about 5 to 10 blocks.

 

in the case of RB30's, you should ALWAYS rebuild the bottom end, and put in some new rods for good measure. replace all the rotating bits, and balance the entire rotating assembly.

 

add to the fact that RB30's are a touch over-squared in terms of bore/stroke, and you can readily see why keeping revs within a realistic range are ideal.

 

I've compiled a naturally aspirated engine on Dyno2003 desktop software, and I've managed to make power all the way upto 9200 rpm, but peak torque is 268 ft-lbs at 5000rpm. peak power in excess of 9000 is unrealistic for my driving habits and applications, but knowing that the power is there is cool.

 

im putting spool rods, je VG30DE 10.5:1 pistons, stock headgasket (or thinner, for higher compression.... want to get 11:1 max) and acl race bearings inside my shortblock. RB26 head with HKS cams and cam gears.

 

not sure if im going to rebuild the valve train first time around.

 

safe RPM limit for me is going to be around 7600. valve float might be an issue at 8000+, but that's mostly it.

 

GET YOUR CRANK balanced, and get your CRANK COLLAR installed, or else you'll be having trouble balancing your cheque book shortly after un-balancing all the parts in your engine due to oil starvation. AND, no matter what you're building (Turbo, Super, or N/A), get the oil oriface machined and tapped and either ready for use or blocked off if you're going N/A). save yourself the time of doing it later if you decide N/A is not good enough.

 

p.s. - one of the individuals advising me on my build before taking it to machining is one of the well-reknowned RB builders on the SAU 200 page thread.

[jdizzy204]

so careless, what is the effective CR with the vg30 pistons and are there any modifications needed to make those fit. i too will be going with a rb26 head and a garrett to4z.

[Careless]

so careless, what is the effective CR with the vg30 pistons and are there any modifications needed to make those fit. i too will be going with a rb26 head and a garrett to4z.

 

bore is 87.5, wrist pin size is 22mm, so you'll need to get some rods with 22mm small ends.

 

you'd need to bore the stock 86.5 bore out to 87.5 or around there (specs on forged alloy clearance and warm-up delay come with the package of pistons). Effective compression is yet unknown due to me not having either the engine (over the ocean right now), the head, the pistons, or the rods (everything is going on order next month)...

 

it should be around 10.5:1 with factory product parameters, but with some decking here and there, im sure it can be manageable. And the reduced deck height (if any) will contribute to less displacement, where the 87.5 mm bore will fill it back up to stock 3.0 litres.

 

I'm looking to get 3.1 litres, or close to there.

 

This is going to be one of my first COMPLETE engine rebuilds that i'll be doing for myself, so if i buy the JE pistons and they don't work out too well, then I'll just resell them for a couple hundred less or something. I figure it's better to try myself and experience the differences rather than go on hearsay.

 

Price you pay to learn, I guess. I'll keep you guys posted of course.

 

ROCKET INDUSTRIES has a RB30 Mainstud kit. I've called ARP and fed them the parts number, and it seems that the gentlemen helping me with sourcing the kit informed me that the rocket industries RB30 main kit is comprised of pick and pull bin bolts.

 

If you want a set of RB30 main studs yourself, you need to get the size of main cap, measure from top to bottom with a fine micrometer, and then measure depth into the block with a depth guage. measure the taper size into the block orifaces, and measure the thread pitch and bolt size. DONT ASSUME that all the holes are the same. check them all. be smart about it!

 

They will then source out the sizes of bolts needed to make you a kit. I was told to do it this way by the ARP rep because he too explained to me that getting them from Rocket would cost an arm and a leg in shipping, and that he can do it for substantially cheaper.

 

So if anyone has already pieced togehter one of these for themselves, and sells them here, let me know. Or else I'm going to piece them together myself and sell them here for a substantially reduced price to keep Hybridz flourishing with RB30 yum-yum =)