Stock Motor Rb25det Good To 700whp?

[R31Nismoid]

How much is considered high rpm?  7k...?  I'm about to put a set of wiseco forged pistons on the standard rods, and then increase power to roughly 320rwkw on race gas.  The car will stay at 290-300rwkw for daily driving, but make 320rwkw for track purposes.  Has anyone gone a similar route with their setup?

for $400 why wouldnt you put a set of GTR rods in?

it makes no sense at all.

Then your fine for 350rwkw+ and very safe

cheap investment for a motor you want to last.

Stress of big power on stock rods... time bomb

[SleepingTalon]

Well, even with all things being equal, conditions being optimal, and having a good tune on the car, I just dont see it holding up for that long. I see some people saying that 375rwkw is fine, but never from someone who actually OWNS and RB25, lol. Most other people have had the same experience that I've had, with that being a 300rwkw threshold for the standard bottom end. A rod that snapped at 278rwhp seems to be a possible tuning screw up. That number is real low for the motor to come undone without there being error on the tuners part. RB26 rods are pretty damn strong, but the pistons are also not quite up to the job of HUGE hp demands, correct? Meaning, from my experience, they're not quite on the same level as that of a supra, which can make 600rwkw on the stock bottom end no problem.

[SleepingTalon]

for $400 why wouldnt you put a set of GTR rods in?

it makes no sense at all.

Then your fine for 350rwkw+ and very safe

cheap investment for a motor you want to last.

Stress of big power on stock rods... time bomb

<{POST_SNAPBACK}>

That's a very good point. The reason I haven't added them to my build list is because I'm building the car for a customer, and it's not my choice. The ringlands busted on 2 of the pistons, and that's why we're putting new pistons in. Where can I source GTR rods? Thank you, I will make the suggestion to my customer. Sourcing Skyline parts in the USA isn't the easiest task in the world, which is why I frequent this board. The car made 295rwkw at 19psi with an HKS 2540. The rest of the motor was stock, but with the pistons coming apart, it's time to upgrade.

[N I B]

Just grab a set of USA made Eagle rods,$800 in AUSTRALIA So USA price would be very low.

[R31Nismoid]

this forum... for sale section.

might cost a tad more in postage.

Reccomend to the customer to use the rods.

Cheap upgrade thats definately worthwhile.

[StageZilla]

i got a set of r32 gtr rods for sale $300+ postage if ya like, i can send to USA no probs, not sure on freight though

[SleepingTalon]

I will call him tomorrow about it. I'm pretty sure he'll do it. I totally agree with all of you, as there is no point to not doing it the right way when you already have the motor apart. So the stock rods shouldn't be taken above 300rwkw, even with forged pistons? I guess that's what others have experienced as the limitation of them. So I assume that everyone here would say that 522rwkw on the standard motor isn't conceivable? At least, I dont think it is...

[SleepingTalon]

i got a set of r32 gtr rods for sale $300+ postage if ya like, i can send to USA no probs, not sure on freight though

<{POST_SNAPBACK}>

Are the GTR rods direct bolt in, and are there any fitment issues with the rod bearings? If not, where can I purchase those? Is there anything else that needs to be done to fit these rods into the motor?

[N I B]

Direct fit.

[SleepingTalon]

Which bearings do you use when fittings these rods? Do the old wristpins work, or is there another way they need to be fitted? Do ARP's work on these rods? Any other specifics would be greatly appreciated. StageZilla, I just talked to my customer and he would like to purchase the rods from you, so it looks like you sold a set! Thanks again!

Edited December 3, 2005 by SleepingTalon

[N I B]

VG30 ARP bolts will fit the GTR rods,The wristpins are the same.

There is nothing needed to use GTR rods but a balance job is a good idea.

[SleepingTalon]

Does anyone have the correct part number for the rod bolts because the part number (ARP 202-6005) I found actually corresponds to the SR20, not the VG30. Is it the VG30DET or VG30DETT? There are 2 different part numbers listed in the ARP catalog for those 2 motors. Actually 3 different part numbers if you count the SR part number I listed above. Any rod bearing recommendations, and a good place to purchase those from? Thanks again!

[N I B]

SR ARP bolt fits the RB25 Rod,They only list 1 part number in Australia for the VG.

ACL race bearings are working well in Australia but would not be in the US i say.Get StageZilla to send you a set with the Rods.

[Beer Baron]

i must say 295rwkw from just a 2540 is a pretty good figure. was this figure dynojet?

[SleepingTalon]

i must say 295rwkw from just a 2540 is a pretty good figure. was this figure dynojet?

<{POST_SNAPBACK}>

Yes the dyno we use at the shop is a dynojet. However, as I said above, we do have a dyno dynamics dyno here too. Infact, it's only about an hour away from the shop. While the dynojet was being installed, I dynoed a WRX over at the dyno dynamics dyno (www.dyno4mance.com), and the car made 253awkw. A few weeks later, after the dynojet was delivered/installed, we put the same car on the new dynojet (www.batlground.com) and it made the EXACT same numbers. I was sure it was gonna read higher, but it didnt. Needless to say I was VERY suprised. I've always been under the assumption that the dynojet read high, but in my ONE experience in testing this theory on the same car, the numbers were the same. I also put my new Audi S4 on the dynojet, and when comparing it to other dyno plots from other people who use different dynos in the USA, I noticed that my numbers for my S4 are lower too. I guess the true way to test this theory is to go put my S4 on the dyno dynamics dyno, and see what numbers I get, but that'll have to wait for now. As a tuner, I dont really care about numbers. All I care about is repeatability. I mentioned above that the dyno dynamics dyno's have a load control on them, and I wouldn't be suprised if that had something to do with the number repeatability between different dynos. Who knows...

Edited December 3, 2005 by SleepingTalon

[mikymouse]

What do you plan to do to the customer's engine? Just rods and pistons? Keep us up to date. Sounds interesting.

[SleepingTalon]

This car started off as something small, and like most, has turned into something much larger than anticipated. Thanks to this forum though, things have gone smoothly. Rods/Pistons are being fitted so that the motor can sustain more boost and a more aggressive tune. The head will remain stock, with the only exception being a new headgasket and ARP's. The 2540 will be the turbo he's using, although it was not by choice. The customer purchased many of these parts with the car, so we're making the best of what he already has. If it was up to me, we'd be using a GT30R with the larger A/R housing. Anyway, fuel tuning is done with a SAFC2. It's got stock timing in the car, although with the SAFC2, it's not uncommon to see more aggressive timing numbers due to the way it adjusts the a/f mixture. It's fitted with a walbro fp, SARD 550cc injectors, and a Nismo AFPR. I'm going to leave the boost at 18-19psi on pump gas, which is 93 octane here. Normally, anything above that on that grade of fuel will cause knock. I will up the boost and build the 2nd data file for race fuel. How much boost extra, I'm not sure. I wont know until it's on the dyno and Im able to monitor everything. It's a fun build process, and I can't wait to get to the final product. I'll be sure to post all the results as I go, not that you guys haven't done what I'm about to do more times than I can count! LOL. If anything, I guess it's good to have the extra data on the site.

Edited December 3, 2005 by SleepingTalon

[mikymouse]

Only 93 ron? Do you guys have Premium over there, such as 95RON at least? So are you just going to throw the pistons and rods in the engine and leave the remaining internals as they are? Or, do you need to do other things, such as: Bore and Hone the Block, Balance, Straighten Crank, etc... Sorry, I'm not really in the know with respect the engine internals. Was just wondering, if it is as simple as just installing new pistons and rods. Was always under the impression that everything has to be checked for perfect clearances etc.. Thanks.

[Tommyk]

American octane ratings are different to what we have here

[SleepingTalon]

In the USA, we use what I think you would consider anywhere between 96-98 RON at the gas station pump. I dont know how you measure race fuel, but what I stock is 117 PON, unleaded. As far as the build goes, according to my measurments, there are 2 different bore sizes in the block. I dont know why that is, but it is infact like that, so I'll deal with it. On top of the factory pistons, there are some markings with 2 different numbers. Some pistons say "05" and some pistons say "06", and those happened to be the different bore sizes. I'm gonna bore the block .020 over to fix this anyway, so it's not an issue. Of course I'll be honing as well, as I always do that when I put new pistons in a car. I also grind down any sharp edges on the tops of the pistons to prevent any hotspotting. With the addition of the GTR rods, I'll be balancing the entire assembly as well. All in all, it should be a pretty strong motor. I really wish we could throw a set of cams in, but with this being a drift car, he really doesn't want it to overpower what it's being used for. If this was a drag car, I'd be knife-edging the crank, and using aluminum rods, but for 300-330rwkw, it's not necessary. It's not always necessary to balance the assembly, as I've built motors and just put pistons/rods in, with just some ball honing, and they were fine, but I'm gonna take the extra step with this one. This is a similair build to the Dodge SRT-4 that I did awhile back, with the exception of the Dodge having a built head. I figure with the use of race fuel, a heavy duty bottom end, and headgasket w/headstuds, I should be able to run a good bit of boost. Does anyone have pictures of the GTR rod next to the GTS rod? What's the difference between the two? Is it visibly bigger and a heavier rod? I'm just curious as to what's actually different between the 2 pieces...thanks!

Edited December 3, 2005 by SleepingTalon