My 3.5l v8 240Z soon to be RB25DET

[sco_aus]

I can tell you first hand, if mounted properly, like mine, it wont be anywhere near it.  You can have a look at my build up and it has lots of pics on how my box was mounted and it works a treat.

http://www.viczcar.com/forum/index.php?topic=1560.msg11199#msg11199

The stock turbo won't last long at all.  Are you going for power or response?  I reckon a GT3540 is too big unless you want a lot of power. Around GT30RS is a good size for response and will easily handle 200rwkw and allows for more power later on.  You will find you will be running very low boost to make 200rwkw, with the above mods being similar to mine, it had no problems at all making 250rwkw on 17 psi (barely even in the rated zone of my turbo) and on 14 psi made 210rwkw..  I am pretty sure the XR6 turbos use that turbo on a 4ltr... lol

[Lynton]

I hear that the reason some people use an RB20 rather than an RB25 is the rebuild and/or maintenance, mods and add on's is way cheaper than an RB25, yet can still produce as much power at he wheels is this so? Lynton

[zzzzed]

you can still get the power out of an rb20 but the driveability will not be as good due to the lack of torque

 

[sco_aus]

Its a bit more cost, but just leaps ahead of the 20.  The 20 is great if you dont want to go too serious, just have a bit more than a worked L.  You can't reliably get anywhere near 250-300rwkw off a stock (internals)RB20 though. But 150-200rwkw is plenty for a street car and that would take a lot of work to get that from an L series, so definately a good option for a quick street car.

[mrp69]

Yeah it will do for now

 

But will be building a  rb30 with 25 or 26 head my mates an air craft engineer

 

So power will be massive later on

 

Just got to save to finish the body now

 

Peter

[sco_aus]

30/26s rock, good choice.  So much fricken torque from them too.  I have a guide to building a RB30/25/6 somewhere i could dig up and email to you if you want.  It has a fair bit of info on there on whats needed and how to do it.

[mrp69]

 

email it over

 

h_pavlo@hotmail.com

 

also pm me your number to have a chat

 

peter

[Aaron Neubauer]

I didn't think 240Z were heavy enough to have 3000cc force induction?

 

http://www.infrastructure.gov.au/roads/vehicle_regulation/bulletin/pdf/NCOP3_Section_LA_Engines_3Feb2006.pdf

 

Refer page 18

 

They better not be!  I just got rid of the spare RB25 VCT head I had!! 

 

http://www.geocities.com/rb30_twincam/

[mrp69]

 

pretty sure your ok to put it

 

will confirm with engineer but im sure he told me u can do it

 

peter

[nuclear_z]

The other problem with doing a RB30/25or26 is because they never came out in a factory car they never had an emissions test done on them, so its harder for engineers to state they comply with the standards of the year of manufacture

 

Of course, owning a 73 this doesnt matter for me as according to my engineer, any engine that is fuel injected would pass the tests for that year...

 

Hows it coming along Peter?

[mrp69]

 

everything is bolted in

 

mechanic is making the intercooler and intake pipe

then next is wiring

and fuel pump

 

then wheel alignment and suspension adjustments then im driving

should be done sometime saturday

fingers crossed.

 

peter

[dazzed]

thing is you allready have the goodys, light alloy v8 engine, ok it may not be that touquey butt, its a v8, and someone has allready done the hard yard conversion, why dont you just refine what you already have?, or you can bore and stroke to 4.4 litre capacity, back in 2005 ndsoc had a weighing scale day, we hired 4 scales from a motorsport retailer and weighed 30 cars compiled of mostly zeds and skylines gtrs and gtirs and 180s and 200sx .  took us a while too come to the grips of weight scaling cars but in the end we figured it out, the best ballanced car on a 50 to 50 weight scale on each corner with the driver in the car and out of the car was a V8 , this would automatically assume that a zed was better dynamically with a V8, so dont rule a V8 out , what the V8 does is centralises the weight rearward or further to the centre of the vehicle , mind you this was on a 260Z 2BY2  so in this case it was a perfect weight distribution factor, in fact we were so indenial of the figures of weight distribution we had achieved on the 2by2 it spent most of the time on the scales justifying figures, so after much carefull rechecking of scale figures it was determined that craig lovegroves car was a perfectly ballanced car considering the few amount of modifications that have been carried out on his car, there are many things that effect this ballance , fuel volume , engine configuration, displacement, battery posistion, overall weight and displacement, so his V8 powered zed at the end of the day ballanced out quite well , no power figures were taken for this event it was purely to determine  weight distribution figures 

[mrp69]

 

yeah

 

well the v8 motor was sold to a proud owner of a 2+2

 

at the end of the day the rb25 is cheap HP were the v8 isnt

 

potential wise i feel the the goodies that ill put on the rb between new turbo manifolds and the rest will contribute to the Rb30 i want to build later and those motors with out much fuss can get u 700-800hp

all day every day

 

i would want atleast 400-500hp out of the motor when its built and finished

 

what u think it would cost to get a v8 pushing that power

then and how much for the rb30/25 or 26??

 

the price between the 2 is a big difference.

 

thou the v8 i got rid of with a fair amount of money would not reach anywhere near that power

 

big differences in driving the 2 but the v8 option for me ive had it wont something different.

i dont plan on getting rid of the car so if i want to change it in a few years i will or buy another 240 and start again.

 

 

 

[dazzed]

mrp69, a v8 verses a rb motor conversion in a early zed is totally a personall thing, drivabillity is the key remember, and getting it all down to the bittumin, thats what counts, putting the weight at the front back from fitting a V8 and a alloy V8 at that from scale corner weight testing is proven to be far more ballanced than a RB motor, but catch 22 it does have draw backs as so does a RB conversion , i favour both in their potential, but C,mon ya cant beat the raw grunt and sound of a hypo V8, counts me out, i prefer a V8

-

[620Z]

Hi boys. Gee that weigh in day was a few years back now Daniel. I knew my car was 50/50 but didn't realise it was the closest on the day. Just be aware the car wasn't always that way. It handled terrible when all the weight was over the wheels. But new engine mounts moved the engine back some 6 inch's and whalla the car was transformed.

[mayhem]

mrp69....... about time you came to your sences.... but figures your looking for you can water down a little .... power relative to boost at that sort of level might go pop!! i poped mine just last month at 234.3rwkw piston couldnt handle it ... most of the figures printed in mags are utter shit !!! ive seen a guy who clams he had 300rwkw out of a stock 25 with nothing but a fuel pump and a boost controler ... pft yer rite maybe one run just before a rod came flying out ... im now building a 25 30 and its so dam cheap it retarded ... and i would love 300rwkw.. its all stock and for under $500 who is going to complain   

[JP]

The other problem with doing a RB30/25or26 is because they never came out in a factory car they never had an emissions test done on them, so its harder for engineers to state they comply with the standards of the year of manufacture

 

Not just difficult, but near impossible unless you have a pre-74 car or run straight LPG.

[620Z]

Yeah your right Mayhem. As you and I know it's too easy for people to bandish around HP numbers like 700-800 even 500 but the reality is you don't see those numbers very often in street cars. All I say is get the job done, the car on the road and dyno then we can count the numbers. 

[mossy]

Doesn't sound like the 3.5l v8 is overly powerful, i reckon you would of been happy if you had a midly worked SBC under the hood in the JTR mounting position, but it looks like the RB route has been sorted so good luck with it, looking forward to seeing the results.

[Scando]

Bet you can't wait wait to have you're first drive with the RB 

 

I think the 25/30 and 26/30's are definately the way to go.  There's a guy that races a 2 door R31 here in tas and the entire car has cost him around $15K to build including an RB25/30, suspension, some Harrop brakes he bought 2nd hand, etc, etc (he does pretty much everything himself and is very switched on).  It produces around 300rwkw and if you saw it in action you'd believe it!  I've got somewhere around 200rwkw in a car 300kg lighter and he leaves me in a straight line like I'm standing still!

 

As far as dyno figures go...........Lets just say I don't pay too much attention to them.  You never know if the dyno is calibrated correctly or how the power run has been done.  But the thing to remember when you read these power figures in magazines is fuel.  Some of the front runners in my class run elf at around $7 a litre!  I run the avgas used in light planes.  The guy that has the lap record for both tracks here in Tas for my class runs a 200SX which apparently has around 360rwkw.  I heard recently that he runs the avgas used in large passenger planes that most of us can't get our hands on but I'm not sure how true that is.  With this kind of fuel you can get away with much more boost and timing advance without detonation and make crazy amounts of power.

[620Z]

Hey Scando was avgas banned from the race tracks? Or do these guys just run this fuel on the quiet?

[C.A.R.]

Avgas is still OK to use - the Aviation industry never converted over to unleaded fuel.

Aren't CAMS knee-jerk reactions great...

[Scando]

You can still run it in CAMS events.  You just have to apply for a log book from the department of environment through CAMS.  You have to have a CAMS license and a log booked car and it is only to be used in the car that you supply the log book number for (but how would they know!).  It's pretty easy to get, expecially with a 1973 car   They have banned it from a lot of classes of racing now though.  For most tarmac rallys you can still use it in classic classes but modern have to run on 98 pump fuel.

 

Sorry for the thread hijack mrp69.  Make sure you put some pics up when the conversion is finished 

[bluerat]

Sorry Shane, but all rallying including Tarmac is Unleaded only, has been for a while, Re Lurch's comment on CAMS knee jerk reactions. They were doing fuel testing everywhere at Targa this year. Hillclimbs are a grey area as you can be on a public road, technically you can only use it on the track. With Targa (not sure about CAMS rallies) you can add octane booster to your 98 if your in classic.

[Scoota G]

Sorry for the thread hijack mrp69. 

 

This isn't a Thread Hijack you've just flown it into a building.