Turbo upgrade?

[Mafioso]

Was wondering what turbo would be the best to upgrade on an rb25det motor.. looking for a good street/track use turbo..

[RazorGTR]

A lot would depend on your budget.

Apexi and HKS do great turbo upgrades. As does Trust and a few others.

A guy renting from me just put a GT25 turbo on his S13 and it has the largest exhaust houseing available.

on HKS maybe a single GT3240 or even a GT3037. Then again depends on how much lag and how much power you are looking for.

Give me a price range and a power figure your looking at and I can be a bit more specific.

[Mafioso]

Well, somewhere that stock rb25det internals could handle.. like 500ish rwhp.. and around a 2-3k budget...

[RazorGTR]

You wont get that reliably with stock internals. And I doubt you will get that on that budget. You may but you would be hard pressed

You are going to need a T41B or a T08 single turbo. the factory compression ratio is too high for big boost so you will need to do the pistons, cams, exhaust manifold, external waste gate, fuel pump, front mount of at least 600 x 300 x 100, 720cc injectors, ecu, and port the head. Not to mention the exhaust and pod filter.

I hate to be the bearer of bad news but the RB25DET just wont reach that on stock internals or with much of the stock bits at all, and the ecu is another restrictor.

[Mafioso]

So what happened to everything I heard about the rb25 and rb26 stock block being able to handle upwards of 550 hp?

[RazorGTR]

The blocks yes but the factory internals on a steady diet of it not. The RB26 will do it for a while then the ring lands will compress. The factory pistons are not as strong as people think they are, neither are the rod bolts. Remember the RB25DET block is NOT as strong as the RB26DETT block, nor is it going to handle the same power levels.
Also I have no idea what these items cost in the states either.

RB25DET

I did some new figures and here is what will give you what you want on a limited budget. The items with ( * ) are a must. I have put what they cost here in New Zealand but I would suspect you can get them cheaper in the states. Also halve the price for currency converting.

Fuel pump * ( Bosch motorsports $450)
Fuel pressure reg * ( Nismo $300 )
Front mount * ( Second hand 600x300x100 $1,000 )
720cc inject * ( Second hand $850 )
ECU * ( Second hand link $500 )
Pistons * ( JE forged $1,500 )
ARP bolts for the bottom end * ( $900 )
3 1/2" exhaust * ( Custom $900 )
Pod filter ( Apexi "best" $450 )
Turbo a Trust GT35 or equivelant ( New $3,000 )
Electronic boost controller ( New Profec B $800 )
External wastegate * ( Trial $1,100 )

Now if your lucky and paitent you may find good deals on the net in Japan and import the items yourself. Also again I am sure you can get items like JE pistons cheap there as we pay double duty plus mark up on them. Same with the fuel pumps and ARP rod and main bolts.

[NightXCZ77]

Originally posted by RazorGTR
The blocks yes but the factory internals on a steady diet of it not. The RB26 will do it for a while then the ring lands will compress. The factory pistons are not as strong as people think they are, neither are the rod bolts. Remember the RB25DET block is NOT as strong as the RB26DETT block, nor is it going to handle the same power levels.
Also I have no idea what these items cost in the states either.

First off, you make me laugh !!! Here's the deal....The RB25DET block isn't as strong as the RB26DETT ??? This I find funny because the 25 and 26 use exactly the same block. Even the RB30DET uses that block. The only difference between the 25 and 26 as far as those bottom end internals goes is the displacement. The 26 has a beefier crank and a longer stroke. The only reason the 26 can handle more stock is because it has a lower compression ratio than the 25 due to stroke. The 26 also has stronger valves and springs than the 25 which is why the 26 head is more sought after. Factory pistons will go over 20 psi.... that's pretty strong to me. I've even seen a GT-R hit 28 HP on stock pistons and internals.....

Night

[Gonthrax]

Originally posted by NightXCZ77


First off, you make me laugh !!! Here's the deal....The RB25DET block isn't as strong as the RB26DETT ??? This I find funny because the 25 and 26 use exactly the same block. Even the RB30DET uses that block. The only difference between the 25 and 26 as far as those bottom end internals goes is the displacement. The 26 has a beefier crank and a longer stroke. The only reason the 26 can handle more stock is because it has a lower compression ratio than the 25 due to stroke. The 26 also has stronger valves and springs than the 25 which is why the 26 head is more sought after. Factory pistons will go over 20 psi.... that's pretty strong to me. I've even seen a GT-R hit 28 HP on stock pistons and internals.....

Night

Yes, they do use the same block, but the internals arn't as strong. Sure they could handle 20+psi, but for how long? And with what other things? (Fuel pump, fuel pressure reg, larger IC perhaps front mount.) I can't say exactialy what is different between the two, but I would take Razor's word for it. He has had a good deal of experience with GTRs and GTS-Ts, having owned both and been around quite a few quick ones.


(Not trying to flame either, just agreeing w/ Razor)

[NightXCZ77]

Originally posted by Gonthrax


Yes, they do use the same block, but the internals arn't as strong. Sure they could handle 20+psi, but for how long? And with what other things? (Fuel pump, fuel pressure reg, larger IC perhaps front mount.) I can't say exactialy what is different between the two, but I would take Razor's word for it. He has had a good deal of experience with GTRs and GTS-Ts, having owned both and been around quite a few quick ones.


(Not trying to flame either, just agreeing w/ Razor)

I'm not trying to flame, but you just agreed with me, not razor. Razor chose to say, and I quote, "Remember the RB25DET block is NOT as strong as the RB26DETT block, nor is it going to handle the same power levels."

You agreed with me, they use the same block which means that the RB25DET block is no weaker than the RB26DETT block, and that both blocks can handle the exact same power levels because they are the same block.....this is not judging by internals.

For 20 psi, you could run all day depending on how you tune your engine. I don't recommend it at all, but I know it's been done. I wouldn't run mine that high for an extended amount of time without building my engine first. Things that you would want to get to run 20 psi for short periods of time (such as drag races or street races) would be larger injectors, FMIC, boost controller, larger turbo, and a fuel pump.

Thanks for agreeing with me. It doesn't take owning cars to know about them, it takes working, dedication, and research on cars with a passion to become an expert. I am not yet an expert, but I am on my way of learning the RB motors forwards and backwards.

Night

[RazorGTR]

First off they are two completely different blocks.

Second the bore is the same yes but as you have just said the stroke between the two is different you got that part right.

The craddles are completely different and not interchangeable. The dimension are different and so is the strength. You can not mount the gearbox out of a GTS4 or a GTR to the block of a GTS25t, while the R33 GTS4 block you can funny that.
so what does that tell you? the blocks are different in not only the back of the block but in the size and strengths of them. The R32 GTS4 block is different that of the R32 GTS-t block. The are heavier and much stronger. You don't get the flex out of them as you do in the 2wd blocks.

Now you mention 20psi on factory internals. Ok for how long? A steady diet of that and you WILL crush the ring lands. How do I know this? Well lets see. (4) R33 GTS25-t's have had that done already, and (3) GTR's already that I know of personally. I know the owners and I know the cars. They were tuned and other bits put on properly yet the same thing happended on all 7 motors.

Now you mention the RB30. Well that was used in the R30 and R31 skylines, and the VL comodore. They were single over head cam motors. The major difference there is the mounting for the trans has the same pattern as the GTR and GTS4. how do Iknow this? A tuning house by the name of Advanced Imports did a 3 litre conversion on an R32 GTS4 some years back. They put an RB25DET head on it. It was a nightmare from hell to do and as I read the article and talked to Peter Hopkins about it he says and I quote " never again. From the begining it posed many problems getting it to work right".

Another notable is the fact once you stroke the RB26 block to 2.7 or 2.8 litres #3 cylinder has a tendancy to crack. Again how would I know this? Well Crodyon Wholesalers R32 GTR has went through 3 count them 3 N1 blocks with the same failure. Reece Megreggor, current holder of the quickes 4wd car in Australasia has had it happen as well and his is not even stroked.

If the R25 block was so strong then why don't the Japanese use them instead of the more expensive or should I say much more expensive RB26 block? In the JGTC all he Skylines are 2wd and up until recently all used the RB26 block. They did not use the RB30 or RB25 blocks, and that was for a very good reason. Reliability and strength.

I am not taking anything away from the RB25 block as yes it can produce some good hp numbers. In fact I have heard of a few in Japan pushing 900hp, but they don't last long even with the right gear in them.

People need to get it out of their heads that all the RB blocks are the same in strength and durability. If they were Nissan would have not made the RB26 block as a seperate casting as they did. The would have merely incorparated the other blocks to fit as needed.

You don't have to beleive me. Contact these following companies and ask them for youself.

Lee Sutton @ Advanced Imports
http://www.advan.co.nz/

Nick Jenkins or Greame McDonnald @ Croydon Wholesalers
http://www.croydons.co.nz/

Sub Zero In Australia
http://www.sub-zero.com.au/

Rob Bryan @ Possum Bourne
http://www.possumbourne.co.nz/index.html

Now I have provided you with the means to get proper information. Please do so as you will learn a lot

[SkylineUSA]

Night, try to be little more friendly. Not combative.

Razor knows his stuff, plus he doesn't come off arrogant.

Razor,

Thanks for enlightening us on the differences in the blocks.

[RazorGTR]

Cheers

I hope no one reads more into what I said as an informative post. I was not flaming or trying to put anyone down. Hence my smiley.

While I do not know everything about Skylines as I am still learing. Like 99% of the people visit AF. I do have fortunate position of getting information from extremely reliable and viable sources.

After all I need to know as much as possible having owned my third one in 4 years

God I wish they were sold new in the States when I was there.

[Gonthrax]

Well now that I've successfuly stuck my foot in my mouth...
Thats what I get for posting at 3AM

Anywho, Vince, you should write technical manuals.

[RazorGTR]

No way. I don't know that much about them. Wish I did cuz I would open my own repair and tuning shop. Most of what I know i got from talking to the right people and going through the experinces as well as mistakes made by others and myself.

In the ever quest for power you have to talk to the right people. You find that many times opinions vary on to what is the best approach but at the end of the day the different combinations all have a central start point. It is getting there that can differ.

I really enjoy passing on that knowledge in hopes that I can prevent someone from making a simular mistake which in the case of tuning and upgrading can be very expensive and heart breaking.

[Nemesis]

Originally posted by NightXCZ77

Even the RB30DET uses that block.
Night

Didn't realise there was ever an RB30DET made, at least not by Nissan.

RB30 block makes a good upgrade for the 25t when mated to a 25DET head....