Max Power Out Of Neo

[drgnball34]

I've been hearing that the Neo engines can only crank out around 240rwkw on stock internals due to compression setup...Surely this is a load of crap huh? Its the last of the RB25DET... Engineered to perfection. If any, it should be able to pump out more then the R33.. My aim is for 350wrhp on stock internals. Does having a oil cooler help with reliability or is it only for track? Also geting a head gasket to lower the comp help much either in terms of reliabilty?? Or is it only needed for extreme boost levels?

[N I B]

Ive seen NEOs with hiflows limited to about 300rwhp because of detonation have thicker head gaskets and cam gears to properly time the cams after raising the head pickup close to 50rwhp due to the extra timing they can then handle.NEO was built for tighter emission laws.

[Craved]

heard that the NEO runs GTR rods, theres a plus there.

[N I B]

They dont have GTR rods.

They have a lower combustion chamber roof, different pistons and solid cam buckets and slightly different oil pump.

[Craved]

hmm fair enough

[R31Nismoid]

I thought the NEO had the GTR rods aswell... a few of them have been apart now and have had GTR rods inside them

[N I B]

Never seen one NEO with them.

[Bluprint]

Going by Abo Bob's rebuild thread, they do have RB26 rods and apparently RB26 solid lifters too.

[N I B]

They dont have GTR rods or lifters.1/2 the lifters are Alloy unlike GTRs

[MR331307]

From what i have seen

they do have GTR style Rods in them as i have pulled one apart and compared the rods sizes between regular RB25 & RB26 ones.As for the buckets in the head i compared them to gtr ones i have sitting here and they look similar but the shims underneath are different and to me they have different length Valve Springs.As for the oil pump they look the same didnt take to much notice to the difference between them.

As for power

More Timing + More fuel = Big Power = good for drag racing

Less Timing - Less fuel = Average power = good for track use

I am making 540 hp now out of a regular rb25.Thread Max HP out of Rb25.I aint gonna go on to much but its all to do with tuning and sufficent intercooler ETC to make safe Reliable power out of the RB standard Motors.

Comp in the NEO motors is what holds them back.Your tuner will need to work around this

[N I B]

Ok then who wants to buy a few sets of NEO RB25 rods to Upgrade their R33 Rb25s?Their the same as R33s sorry.Did you see that the intake buckets are Alloy?

[Tex Willer]

The power output of these engines are often a question of fuel quality.

Long duration cams will lower compression pressure.

Bigger turbos/exhausthousings will lower backpressure.

Very high peak power numbers are possible at high revs, because of the short

stroke and rodlength/stroke ratio.

500nm at 4000rpm gives 380hp.

500nm at 8000rpm gives 760hp. both with the same combustion pressure.

my answer is I don`t know the limits..

[Abo Bob]

Ok then who wants to buy a few sets of NEO RB25 rods to Upgrade their R33 Rb25s?Their the same as R33s sorry.Did you see that the intake buckets are Alloy?

I suggest anyone doing an RB25 rebuild take you up on this offer. Not only do they look the same but I've had someone look up the part numbers for R34 RB26 and R34 RB25DET and the numbers are the same.

Also the R33 and R34 RB25DET's both have 9:1 compression ratio which can be a limiting factor in putting lots of boost into them.

Bass Junky has about 250rwkw without lowering the compression ratio but he does have cams as do I.

There doesn't seem to be many people succesfully putting a lot of boost into a NEO without cams or lowering the CR. I can't think of any offhand.

The NEO does have solid lifters as does the RB26 but they are not the same.

The NEO exhaust valves are 1mm bigger than the RB26 items. This could help get more power from the same or less boost all other things equal.

It seems to me that without lowering the CR the NEO can take about as much boost as a non NEO. Depends how far you want to push it, how good/consistant your fuel is, and how well tuned it is. The power levels are probably similar, perhaps a slight advantage to the NEO. If injectors aren't being changed the NEO ones are 350cc but earlier ones are 370cc. which could be a limiting factor.

[N I B]

I do have some rods (Even one snapped in half) Only done 3 34 engines and all had 33 rods.

They do snap just above the rods oil squirter.

[Abo Bob]

Got any pics?

[Bass Junky]

Yeah, we ran into a brick wall at about 250rwkw.

We have pulled timing for the most part and dial in 2 degrees for a squirt every now and then.

The engine wouldn't take any more timing or boost. I'm running about 0.9 bar with Bp Ultimate.

260 degree cams.

If the answer to a bucket load more power is a hea gasket, I'll be wrapped.

BASS OUT

[Sydneykid]

Yeah, we ran into a brick wall at about 250rwkw.

We have pulled timing for the most part and dial in 2 degrees for a squirt every now and then.

The engine wouldn't take any more timing or boost. I'm running about 0.9 bar with Bp Ultimate.

260 degree cams.

If the answer to a bucket load more power is a hea gasket, I'll be wrapped.

BASS OUT

Try some Shell Optimax Extreme 100 ron, dropped the knock from 70 to zero in the R33. No other changes.

We have had 305 rwkw out of an R34GTT. Tomei 260 Poncams, R33GTR intercooler, ported and polished cylinder head, standard head gasket (I don't use thick ones) and a Garret GT30. It wasn't all nice to drive, too peaky, lots of lag, poor throtle response. So we went back to 265 rwkw (GCG high flow) at 1.1 bar, much nicer to drive and ultimately faster point to point. With Extreme I reckon we could have got to 280 rwkw at 1.2 bar, which would be plenty.

cheers

Edited April 11, 2006 by Sydneykid

[Abo Bob]

Got any pics?

I guess not.

[discopotato03]

Great info but starting new string .

Cheers A .

[infected flow]

I suggest anyone doing an RB25 rebuild take you up on this offer. Not only do they look the same but I've had someone look up the part numbers for R34 RB26 and R34 RB25DET and the numbers are the same.

Also the R33 and R34 RB25DET's both have 9:1 compression ratio which can be a limiting factor in putting lots of boost into them.

Bass Junky has about 250rwkw without lowering the compression ratio but he does have cams as do I.

There doesn't seem to be many people succesfully putting a lot of boost into a NEO without cams or lowering the CR. I can't think of any offhand.

The NEO does have solid lifters as does the RB26 but they are not the same.

The NEO exhaust valves are 1mm bigger than the RB26 items. This could help get more power from the same or less boost all other things equal.

It seems to me that without lowering the CR the NEO can take about as much boost as a non NEO. Depends how far you want to push it, how good/consistant your fuel is, and how well tuned it is. The power levels are probably similar, perhaps a slight advantage to the NEO. If injectors aren't being changed the NEO ones are 350cc but earlier ones are 370cc. which could be a limiting factor.

im getting 291rwkw with 8.9:1compression.. and 20psi boost...