Rb30 Head On 25 Block

[pf.]

Now back on with the build I will be tearing the head down tomorrow or saturday will post pics.

[walky01]

So your saying (160 rwkw) "ONLY" which equates to 208kw at the engine, which is what everyone uses...car dealerships etc... a brand new showroom falcon xr6 has what 210kw???? except its 2013 technologoy, not half 86 half 96.....over 20 year old parts..... "ONLY"

[walky01]

Ill post figures up of mine when its done on the dyno, if all is well hopefully around 165-175kw ATW......

[pf.]

So your saying (160 rwkw) "ONLY" which equates to 208kw at the engine, which is what everyone uses...car dealerships etc... a brand new showroom falcon xr6 has what 210kw???? except its 2013 technologoy, not half 86 half 96.....over 20 year old parts..... "ONLY"

Ok it is a good amount but it is not in any way remarkable look at the hp per cc it is fairly average considering you can buy a r1 tune it and make near 200hp.

Also the e36 BMW's can make 300hp with a few mods the xr6 falcon is pretty much the same engine from the xf's just with 4 valves per cylinder. What is the hp per cc or ci of a xr6 compared to some older cars there are some that do near the same.

Edited April 5, 2013 by pf.

[Captain Natro]

Ok it is a good amount but it is not in any way remarkable look at the hp per cc it is fairly average considering you can buy a r1 tune it and make near

Also the e36 BMW's can make 300hp with a few mods the xr6 falcon is pretty much the same engine from the xf's just with 4 valves per cylinder. What is the hp per cc or ci of a xr6 compared to some older cars there are some that do near the same.

Yer it's just like an xf, you know apart from having an over head cam, wait make that two cams not one, oh and 4 valves per cylinder.... Yer..... It's identical

[pf.]

Yer it's just like an xf, you know apart from having an over head cam, wait make that two cams not one, oh and 4 valves per cylinder.... Yer..... It's identical

Lol the 4v vs 2v vibe i'm getting from your post is high

[KiwiRS4T]

http://www.skylinesaustralia.com/forums/topic/423033-for-sale-rb25det-head-rb-hight-mount-manifold-rb-dump-pipe/#entry6806827

[pf.]

http://www.skylinesaustralia.com/forums/topic/423033-for-sale-rb25det-head-rb-hight-mount-manifold-rb-dump-pipe/#entry6806827

Already got one bro but the build on that will be epic when I can afford it. The 25/30 will be turbo and forecasts are in the region of 30k for that build the 30/25 will be cheap as possible porting and chamber work will be the big cost.

[pf.]

Was going to work on the head but got pissed instead so monday will be the tear down then ill have to tear the block down next weekend.,

[mad082]

even at trade prices, etc, you will be spending many thousands to get anywhere near 160kw at the wheels. as i think i said in an earlier post, a mate of mine built a rb30 from the ground up in his r31 and it only made just over 230hp. this thing had a lot of work done. major head work, cams, crank was modified to flow more oil, twin throttle bodies, big injectors, etc, and it reved to 8 or 9k. from what i gather, it may have been the fastest non turbo rb30 in australia (ran a high 13). his old man was an engine builder and had been using rb30s in his speedway cars from the 90's, and was the first person i knew with an imported skyline (had a turbo 31 back in the early to mid 90's).

so to try and similar power with 500cc less is going to be hard work, and the car will drive like an absolute dog (i know my mates did).

as for comparing new engines to old engines, you can't really. they were built in different eras with different regulations and objectives. newer engines run closer to the limit to begin with as this helps them with emissions, and there isn't much in the way of technology advances that can be used to get bigger gains.

but as i also said earlier, i'm happy to be proven wrong about the power you make, but i have a pretty good idea of how poor the reliability is going to be getting anywhere near that power. i know how often my mate had to rebuild his car (but it did have a hard life. was primarily used for drag and burnout comps, but was still registered)

[walky01]

Im probably at 10k and im hoping to make over 160kw atw...wouldnt know yet till its tuned, alot of time and money is spent to do this sort of project. but back on topic...i dont understand what your trying to ask? you want help with putting an rb30 head on an rb25 block....if no one has done it (which no one commented has) then how do you sugest we can "help"..... if hasnt been done there probably is a reason...but by all means do it so when your budget built is better than the 10K plus wasted you can laugh in my face

[StevenCJR31]

pf its good that you are thinking outside the box mate but for the$$$ that you are spending you are not going to get much bang for your buck~dont take this as being negative

take it as being realistic

[bozodos]

I'd hope that anyone doing up an N/A RB motor would be aware of the costs involved, OP I'd say that head design is going to be absolutely critical for your goals (that and a lot of compression).

I recall seeing a triple carb RB30 HR31 from R31House on youtube a while ago, sounded cool too, could always try pissing off the pesky fuel injection? FWIW, 202's are regarded as a lump of a motor as well.

For the money, I'd be putting an LS in it, because you'll probably be spending a similar amount

[niZmO_Man]

That would be an RB30E block with an RB25 head. What OP wants to do is put an RB30E head on a RB25 block.

It is something different, but is it worth the effort/money? We will wait and see.

[bozodos]

The R31House one was a complete RB30S motor from what I saw (as fitted to GQ Patrols).

OP: there are way better N/A engines out there than the RB series to start with, but you probably know that anyway

[xALmoN]

b16 yo, do it.

vtec will kick in.

[pf.]

Ok a bit of an update head was checked by me and was bent it can be straightened. The straightening will increase compression greatly but he 25 block will drop it greatly so I have some numbers to play with So far the head is going to cost me about 2500 I plan on spending 2k on the computer and ignition so to come under the 10k mark it leaves me with 5k for block and fuel system. Costs will blow out so I have to play it safe with my money.

The head price is service,porting,machining and a cam.

[Kiwi_Phil]

so you are spending 10k on an NA 30 Head with 25 block?

This is quite possibly the worst idea I have ever read on a car forum. For 10k do something decent .... even though I hate the idea you can get an Ls1 crate engine for around 6k

[89CAL]

Have to agree. Your better off spending 10k on an N/A 25. Will gain more out of it.

[MBS206]

After 10K, I'm interested to see the result since OP was so adamant a 30/25 will be better then a 25/30.

Will be interesting to see how it compares in terms of fuel and drive ability to Greg's 25/30