Which rods??

[Merli]

Originally posted by GTS-t VSPEC

For the turbo's we are all using I don't see the need for very high revs, it will be making peak power quite early in the rev range.

HKS turbos may very well surprise you I'm running a 8000rpm redline (raised from standard 7000)...

Everytime I dyno the car, I tell them to take it all the way to 8000, and they look at me and say "oh the power curve will probably drop off before then" to which I reply.. "Just take it to 8000".

So they do so, and they all get very surprised when it keeps pulling at an enormous rate all the way to 8000, I'm quite sure if I raised the redline to 9000, it would continue to pull upto there and probably eclipse 300rwkw on 1.2 bar, but I'm not *that* brutal on stock conrods

I'll wait until uprated ones have been put in before doing that :lol: :lol: :lol: :lol:

[Steve]

Andrew,

What model turbo are you running? Where does it come on boost?, and have you done any head work yet? And also, what sort of torque curve are you getting

Spose at the end of the day - when I say I wont want to take the revs that high - once bitten it can be hard to hold back when it comes to the power bug. Originally I think I was only chasing 200rwkw - but the more I get the more I want.

Ultimately spose its better to go a bit of overkill when doing the build - save having to go through the process again. Pretty sure this time, with a rwkw figure of 280-300, that I wont get too much chance to use more except if I only want to go in a straight line and dont mind major traction issues - its all good though.

Cheers

Steve

[Merli]

I'm using an HKS GT3040 with 0.87 exhaust housing. Boost starts to build from around 2500rpm and hits 1 bar at 4000rpm, when the wastegate opens and the turbo really comes on strong. I'm actually not sure what the torque curve is like... I can't seem to find any dyno chart printouts at the moment.

My engine right of this moment is completely stock. It has never been cracked open and is completely standard. It's the only thing holding me back from turning up the boost and dialing up 2 bar.

The thing with doing engine builds, is that there is a lot of time and labour costs in doing so. A good engine builder wouldn't be asking too much less than $2000 just for the rebuild, without any components, so if you were to later on to decided that you *DID* need those conrods, or should have done some prepping of the crank, it's gonna cost you a lot to go in and do that surgery. It's best to sit down and do everything right the first time, with a little more room for future developments...

[Steve]

Thanks Andrew, sounds like a pretty sweet turbo - not too much lag, and goes strong when you want it too. Hopefully the 3037S wont be too far behind.

Cheers

Steve

[GTS-t VSPEC]

I was considering the GT3040 over the 3037, just becasue of the cost saving, hopefully with the headwork I'm doing I will get a bit less lag, but we'll see.

Even on my stock turbo we have pushed the redline to 7500, and power doesn't drop off before 7200, I think it may have something to do with our plenum's.

See'ya:burnout:

[Steve]

Paul,

What is the cost difference of the two? I thought they were about evenly priced?

Cheers

Steve

[GTS-t VSPEC]

Steve,

I'm pretty sure the HKS one is about $1000 more, which I'm not sure will justify the performance gain. I could put this towards cams, which will make a bigger difference.

See'ya:burnout:

[Steve]

Oops, thought you were comparing HKS to HKS

Cheers

Steve

[GTS-t VSPEC]

Nah, GT30 is the garret series, whereas 3037 is HKS brands. All they do it change the trim design, but Garret won't sell anyone else the 3037's, casue HKS have exclusive rights, pity.

I think that the GT3040 will be good, Merli seems to be doing alright with it, and seeing as I'll have forged pistons I should be able to run 2bar if necessay.

See'ya:burnout:

[Steve]

The 3040 probably would be ok, but I think you find the one that Merli is running is a HKS, so you may not get quite the same results that he is.

Have you sussed out the GT35r that Per4manz do - sounds pretty sweet and is the one I would be getting if I didnt manage to pick up the 3037S so cheap.

[GTS-t VSPEC]

Steve,

I will be dyno tuning a car tommorow at SST, so I'll try and catch Grant while he is about, and suss out some details.

See'ya:burnout:

[Steve]

Paul, if you are interested there is a guy selling an HKS3040 on the SDU forum, wants 3600 for it and its brand new. Seems like a pretty good price for a brand new one.

Might be worth a look

Steve

[GTS-t VSPEC]

Thanks Steve, I don't quite have the money together for the turbo yet, just paying for the internals, then I'll save up for the rest.

See'ya:burnout:

[GiJOr33]

Good thread guys. Enlightened me a lot on the path to follow to reach decent power with out going over the top.

I'm looking at doing the internals on my car too. What's the story if i want to use a VL Turbo RB30 block? Do i just need to get longer rods? or will the whole thing be different? Could i use a GTR Crank in it?

I'm thinking of going the Wiseco pistons, GTR Rods and Crank. Will that make the standard RB25 2.6 litres? The reason i'd like to do the RB30 block is cos it will be more streetable, with more low down torque, and the turbo will come on boost earlier. I don't want to go for 800hp. And i don't want to have to do gearbox and diff either! I've got a 3040 turbo as well.

what do you guys reckon?

Thanks

Andrew

[GTS-t VSPEC]

Andrew,

While the RB30 block is a good choice for some, I don't think that the investment of time and money will really be worth it, unless 800hp is your aim. The GTS-t's are more than capable of producing 500rwhp, and still be drivable on the street.

The 3040 is becoming a popular choice, and aslong as you do all the other necessaries it doesn't have to be laggy.

Merli can probably best answer the GTR rods and crank question as that is what he was looking at doing, I think. The Wiseco pistons are a good choice, very good value for money.

See'ya:burnout:

[Steve]

Agreed on the pistons, especially as they come with rings and that is another $200 saving on JEs (I have been doing some more investigating).

RB30 block will give you great torque and off boost response. The best way I have heard of doing this is to buy an rb30 block, (about 400), and a rb25de head, fully prep the block - about $5000 (this estimate came from sydneykid, who does rb30s for his track cars). Headwork is another story, I got a quote from Adelaide Engine Development, and he can port a RB25 head to flow 400hp at atmospheric (no boost) and is quite confident that the head will flow enough for 600bhp at 1 bar - total cost of $700! - I'm definately getting this done. Then all you have to do is get the engine assembled, and put in the car - take out the rb25det and sell it to a commodore owner and you would have recouped some of the cost. (complete with stock turbo, manifold and dump) shouldnt be too hard to unload.

All looks good in theory. Myself I am just going to stick with rb25 as if it will easily make 550+ bhp with the mods I am doing.

If you are after an rb30 - I think mr mayhem was selling an rb30 and rb26 head for about 2100 or there abouts - could be worth a look in, but otherwise rb30 blocks are pretty cheap.

I am pretty sure the difference in capacity from the rb25 - rb26 comes from the placement of the gudgeon pin in the piston - not the rod length - but not 100%

[GTS-t VSPEC]

Agreed there Steve, the RB30 option is great, but alot of work and money is involved. But I will seriously think about that option on my race car, once I finsh this one off.

See'ya:burnout:

[GiJOr33]

Awesome, thanks for the reply... Why the RB25DE head and not a DET head? I wouldn't mind doing the whole thing myself rather than just buy one that someone else has started. And i'd like to stick to the RB25 head as my exhaust manifold/turbo setup will bolt straight on and i've heard that RB25 manifolds don't fit RB25 heads.

Like i said, i'd be going more for the low down torque/response than the all out power. The HKS 3040 turbo should be a good match up for it (or do you think i should go for something smaller?)

Dunno at this stage. Might just go the RB26 Crank and Rods, and get them all prepped, and a set of wiseco pistons instead! I'll have to see.

[GTS-t VSPEC]

The 3040 will be perfect choice for the 3litre, that larger capacity will help spool up, would make 500+rwhp with ease. If you have the time then do it, it will be great, but it is possible to get good power out of the RB25, but it will always be laggier.

See'ya:burnout:

[GiJOr33]

yeah... what about gearbox, drive shaft and diff? how will that handle it? Cos i don't really want to go cracking my gearbox to put straight cut gearsets in either.