Rb24

[Aberax]

Here is the HPI Article on the RB24 build.

[nisskid]

cheers for the help guys, too many good posts to reply to. my biggest worry is the rb20 head really, i noticed URAS has mentioned bores splitting in other rb24 threads, just not sure if it has been substantiated by anyone else. makes u wonder why tomei would have gone to the trouble of the 24 for no reason.

and you need a GT30 size turbo to match... great for a street car if you get pulled over... Then out comes the motor. cost of ownership just went up.

A near stock Rb26 engineered will do the same job, legally.

i'm sorry, but how exactly do u envisage the boys down at regency knowing it has a bigger bore and crank than factory?

[zebra]

I belive that tomei developed the bigger rb20 before the 26 came out or was readily avaliable...hence the use of 4agze slugs...then i guess they adapted it for use with the 26 crank and rods.

Also a note on the HPI rb24...it originally split the bores before it was even assembled...so it had to be sleeved...so if that happens then there goes the budget stroker

[STATUS]

hmm you know the rb24 have a love of splitting bores don't you? i have a purple 4dr 32 in here that is rumored to have the hpi engine in it and its also got a split bore

i have edited it as i remember the HPI car being green-black not purple.

[nisskid]

i have a purple 4dr 32 in here that is in it and its also got a split bore

??

[nisskid]

..and i missed out

[bigmikespec]

hmm you know the rb24 have a love of splitting bores don't you? i have a purple 4dr 32 in here that is rumored to have the hpi engine in it and its also got a split bore

Steel sleeves FTW

[NZM.031]

i spent the evening flicking through all the project R32 articles... they start at issue 44 and got through till about issue 70.

with the td06 and the stock rb20 bottom end, they made 239kw, with full boost at 4500 rpm.

with the td06 and RB24, they tuned it for response, keeping the same power, so it made 239kw but came on much earlier with the cams set up for low end.. it also had the ability to rev out to an 8500rpm limit, but the td06 was out of puff by about 6000rpm.

the turbo was changed for a kkr unit with instantly went to 250kw first run... they tuned it and made 256kw, but boost response was now back to the rb20 state.., coming on at 4500 instead of 3500 like the trust turbo, but thats due to the larger turbo.. if it was on an rb20, it wouldnt come on until 5000 or later..

but its alot of work and mucking around to only have the boost come on earlier.. this all comes down to turbo choice though.. what is cool is that it has no dramas reaching the 8500rpm limit set by the tomei cams and springs.. if you were to go bigger cams, solid lifters, heavy port work, oversized valves, combustion chamber cleanup, itb's and gtr plenum then you would have yourself a nice powerband depending on what turbo you chose and what your goal is....

the rb24 is expensive, but if you rebuilding an engine as a competition or thrashing engine, then its probably not much more costly, but if its an all out track or drift car, where your up in the revs all the time, its probs not worth the effort and risk of splitting the bores.

its a funny conundrum.. is it worth it to build an rb24?? if all it does is bring on the boost 1000rpm earlier?? i must say after reading and re-reading, its obvious why noone really builds rb24's... it simply isnt worth the extra expense... expense that could be better spent on the the head.

if its a track car, probs better to do the head, get it really revving and stay up in the power band, using 4.3 diff gears to get the better torque, but if its a streeter and you want max down low response with a reasonable size turbo like the td06 or 2530, then the rb24 is a good option, but the rb25 is a much easier option, and cheaper too.

i had my sights set on building an rb24.. but we will see... ill refresh my rb20 and go from there, if it doesnt spool the turbo ive chosen, then ill consider the rb24.....

but if one was to pop up for sale... complete... id grab it

shame you missed out.

[STATUS]

Steel sleeves FTW

yep and by then its cost 8k, so just 25 it or 30/25 it as both are cheaper... shit you could forge a 30/25 including purchase price for less than a well built rb24

[nisskid]

i spent the evening flicking through all the project R32 articles... they start at issue 44 and got through till about issue 70.

with the td06 and the stock rb20 bottom end, they made 239kw, with full boost at 4500 rpm.

with the td06 and RB24, they tuned it for response, keeping the same power, so it made 239kw but came on much earlier with the cams set up for low end.. it also had the ability to rev out to an 8500rpm limit, but the td06 was out of puff by about 6000rpm.

the turbo was changed for a kkr unit with instantly went to 250kw first run... they tuned it and made 256kw, but boost response was now back to the rb20 state.., coming on at 4500 instead of 3500 like the trust turbo, but thats due to the larger turbo.. if it was on an rb20, it wouldnt come on until 5000 or later..

but its alot of work and mucking around to only have the boost come on earlier.. this all comes down to turbo choice though.. what is cool is that it has no dramas reaching the 8500rpm limit set by the tomei cams and springs.. if you were to go bigger cams, solid lifters, heavy port work, oversized valves, combustion chamber cleanup, itb's and gtr plenum then you would have yourself a nice powerband depending on what turbo you chose and what your goal is....

the rb24 is expensive, but if you rebuilding an engine as a competition or thrashing engine, then its probably not much more costly, but if its an all out track or drift car, where your up in the revs all the time, its probs not worth the effort and risk of splitting the bores.

its a funny conundrum.. is it worth it to build an rb24?? if all it does is bring on the boost 1000rpm earlier?? i must say after reading and re-reading, its obvious why noone really builds rb24's... it simply isnt worth the extra expense... expense that could be better spent on the the head.

if its a track car, probs better to do the head, get it really revving and stay up in the power band, using 4.3 diff gears to get the better torque, but if its a streeter and you want max down low response with a reasonable size turbo like the td06 or 2530, then the rb24 is a good option, but the rb25 is a much easier option, and cheaper too.

i had my sights set on building an rb24.. but we will see... ill refresh my rb20 and go from there, if it doesnt spool the turbo ive chosen, then ill consider the rb24.....

but if one was to pop up for sale... complete... id grab it

shame you missed out.

nice reply, exactly what i was after.

[Adriano]

hmmmmm I has a 1GGZE sitting in the shed...

I should build a go kart...

JUst biuld a boat instead, the ze would be a good anchour

[_Ryan_]

cheers for the help guys, too many good posts to reply to. my biggest worry is the rb20 head really, i noticed URAS has mentioned bores splitting in other rb24 threads, just not sure if it has been substantiated by anyone else. makes u wonder why tomei would have gone to the trouble of the 24 for no reason.

i'm sorry, but how exactly do u envisage the boys down at regency knowing it has a bigger bore and crank than factory?

no, i more meant, what turbo would you run with an RB24? something rather obviously not standard? Factor in a trip to regency/EPA if you get pulled over(others, not you, I know yours isn;t a streeter anymore). A Stock looking RB26 with engineers cert won't get the same treatment, and if it does, N1's were a factory turbo, use an R34 motor and it would be legal would it not? It would also make the same if not more power than an RB24, and considering it would prob be worth sleeving the block, it won;t be a cheap build.

Cliffnotes:

Officer sees large turbo(high or lowmount) -> EPA

Standard engine bay-> no dramas.

[jdmser]

I ended up going ahead with a Rb24 build because things over hear are a little different. After leaning the motor out and burning up some rings and valves I thought about going with a RB25 or RB26. Over here RB25 motor sets are about $2500 US and RB26 engines are around $3000 US and then I'd need a RB25 trans for another $1000. Made more sense to me to work with what I had. We addressed the thin cylinder wall issue by filling the water jacket up the the freeze plugs. I'm not sure if the big end of the Tomei rods are bigger than the Eagles I used but, there was no need to clearance the bottom of the bores. If it takes up the 2+mm of clearance it has your motors done anyway. I have yet to see anyone post flow numbers for any of the RB heads. I know you can just look at the RB25 head and tell it flows more but, how many people use the flow of their head to it's full potential. A set a +1 valves, a port and polish, and a good set of cams and the RB20 head will flow plenty. I'm building a drag car/dyno queen so I've spent a little more than you have to. Things like coating main bearings, rod bearings, cam bearings, a pistons along with re-nitriding the crank after it was welded, ground and polished. I'm staying away of the forward facing plenums because nobody has provided enough info on their performance to justify spending the money. That and a 3" j pipe will be a go excuse for putting a 4" cowl hood on. Any who, I think I spent a little less then $3000 on all the parts to make the RB24 and then other $2500 in machining and head work. It's not as expensive over hear when you compared to what you would have to pay for a used RB25/26.

[bozodos]

why not just use an LS1 if going for a dyno queen / drag car?

Also wouldn't an RB22 be the easiest and cheapest to build (probably not going to gain a whole amount out of it I guess)

[jdmser]

why not just use an LS1 if going for a dyno queen / drag car?

Also wouldn't an RB22 be the easiest and cheapest to build (probably not going to gain a whole amount out of it I guess)

If it were cheap or easy everybody would do it. I also have set my sights on the track six cylinder record and will be competing in the Sport Tuner Showdown Series. Neither of which can be done with a LS motor. As for power, I'll be running either a T67 or T76 Q trim with a 100 shot. Builder is pretty sure we'll see in excess of 700hp. But what does he know, he only won his class in this.

With a turbo Pinto motor.

[bozodos]

Just that one would have thought in the US there would be a lot cheaper options (hence me mentioning LS series motors) than building a RB24 motor for huge power, have you looked at exporting an RB30 bottom end from over here and using an RB25 head as another option?

[murrayis]

Angry Rb20 ^ sounds like mine does pitty mine still hasn't been tuned.

[jdmser]

Just that one would have thought in the US there would be a lot cheaper options (hence me mentioning LS series motors) than building a RB24 motor for huge power, have you looked at exporting an RB30 bottom end from over here and using an RB25 head as another option?

If I end up splitting a bore on my RB24 the RB30 is what I'll do next. How far can they be bored out?

[bozodos]

I've heard of RIPS or someone doing a 3.3 litre engine, but usually its just a twin cam RB30 using either an RB25DE, RB25DET or RB26DET head.

[_Ryan_]

If I end up splitting a bore on my RB24 the RB30 is what I'll do next. How far can they be bored out?

Spool is working on a 3.4kit IIRC