Whose Done The 26/30 N/a Conversion?

[GTRsean]

Yep, as you know the GTR cams weren't designed to work like this anyways.

Funny you should ask that. I have test driven a dead stock r33 GTST manual and the power delivery is pretty much the same except for the mad throttle response on this.

I'm curious to see what he gets down the quarter. Low 14's maybe. Old RB30E was a best of 15.6.

I'll post up the dyno graph next chance I get.

[GTS4WD]

Please do

[R33_Dude]

That's a good baseline for a NA to be run in. Especially considering the cams aren't matched, the gearbox sounds dodgey, probably needs a better diff most likely, and didn't you say it needs everything from the extractors back looked at? That's pretty impressive really. Run in properly with a (much) more aggressive tune, and those problems sorted out it will be interesting to see its actual power output.

I am left wondering how much torque it is currently producing.

While I'll never have enough cash to do it myself its an awesome project. Keep us posted with the details!

[SABBAi]

Awesome stuff guys. Keep the updates coming

[Silhouette-R]

Well I finally got around to becoming a member of SAU, I'm part of the R31 Skyline Club.

This just happens to be my car, I think someone wanted the dyno graph:

The red line is the new motor RB30DE (186 rwhp) and the green line is the old RB30E (134rwhp).

Hoping that the diff and gearbox hold together down the track it should be good for approxish 14.3 secs, just about the equivalent of a turbo 1J in a soarer, with very mild modifications.

[GTRsean]

About time lol. After all it is your beast!

I want to see more kws but keep that bottom and mid range too.

[Beer Baron]

nice work. if it were mine I would be getting rid of the factory plenum and get some individual velocity stacks. the stock intake is designed to work under pressure and my bet is it's holding you back as it's not suited. even consider some larger throttles, Garage Saurus make a few different options for 26 head that still wants the 6 throttles, just bigger. definately get the intake and exhaust ported and get some big cams in there. around 280-290 degree and 11mm lift+, you'll need the valve springs and retainers to suit and some clearancing work in the head but you've come this far and these finishing touches will really make it nice. the thing is though, to make power with this NA engine you need revs. with the big cams and a better intake you'll be able to make the most of the top end. as long as your bottom end is strong you should be able to rev it to 8500+.

anyway, very cool idea and certainly something different in aus. enjoy.

[NXTIME]

Very good advice, BB. As well as Garage Saurus, SPL racing make larger throttle bodies for the RB26...50mm, I think

[Silhouette-R]

Rookie question, but what size are the standard throttles?

[GTRsean]

They are roughly 47-48 mm diameter standard.

Trumphets on the throttle bodies (read modified plenum), more aggressive cams etc would be a good starting point .

This would be nice lol. 380 hp at the crank, RB26/30DE

Edited September 23, 2008 by GTRsean

[Silhouette-R]

Perhaps there is gains to be made with cam timing ajustment and more tuning?

Yes there can be more adjustment made with the exhaust cam which would give it a definite power increase.

But I don't know if I should spend $500 and get cam gears or spend $1500 and get cams which would give a massive increase in power??

Oh yeah its still running the 1986 2.25" press bent exhaust, so a stainless 3" would help out a lot as well

Edited September 24, 2008 by Silhouette-R

[Eug]

welcome levi, i'd go for the camshafts myself - it's far more cost effective.

also remember to factor retune costs for either mod

[GTRsean]

Cams ftw!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

[R33_Dude]

It depends on budget of course, but cams would give the greatest bang-for-buck in a build like this. Just remember to change the valve springs etc because I doubt they were designed for a lumpy NA cam.

Its good to see someone doing something different despite all the people running around slagging it off. Good job.

[Silhouette-R]

Yeah the cost that I mentioned ($1500 - $2000) would cover the new cams, new springs and the machine work + tune involved putting the new cams in, but the new cams would not be till after Christmas.

I'll put the new exhaust on first so that when the cams go in there won't be anything restricting them, but I'm thinking if the head is going to be pulled off the motor I might get the rods done as well, since it will want to rev like crazy.

[342Four]

stock rb25 rods are nitrided from factory and i think are also shot peened and will handle 8-8500rpm for short periods

cams will shift the power band up, but even at 8-8500 i would imagine that they would be out of puff anyway

i see no need for aftermarket rods

Edited September 26, 2008 by 342Four

[Silhouette-R]

I want to get aftermarket rods cause i'm still running the Rb30 rods which aren't designed to rev into the 7-8000rpm range.

And I don't want a rod going through the block, not good.

[Eug]

yeah but you can do cams and all that with just the head off.

rods means the whole lot has to come back out, then it goes downhill from there moneywise.

-rods leads to...

-full balanced bottom end (crank, balancer, pistons, race bearings, etc.)

-then the cams and head work (port, polish, oversize valves, etc.)

i looked into the same motor setup - and me personally i'd much prefer to do the whole lot at once than gradually do one mod at a time. it's a lot of coin initially but saves hassles down the track. best way is to start with the block and leave the head stock, then when you get coined up do the head. however that's not how people usually mod cars (head first, then block).

the money is why i scrapped the idea. i reckon it's a 15-20K exercise to have it done properly.

[342Four]

I want to get aftermarket rods cause i'm still running the Rb30 rods which aren't designed to rev into the 7-8000rpm range.

And I don't want a rod going through the block, not good.

you will be suprised with the rb30 rods aswell

turbo guys have had them in 8000+rpm in 25/30 and 26/30's boosting big numbers no worries

[Eug]

that is true ash, however an NA car would sit at higher revs for far longer than any turbo car.

NA = revs = power

again be weary with the harmonics issue that the RB30s are supposed to have. not as simple as throwing rods in and voila. knifeblading the crank is also a good idea/