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Ye that's pretty much where the upper limits are going to be.

E85 would see you around the 350rwkw marker. Maybe a tad more, maybe a tad less, always subjective.

I was making 270rwkw @ 17psi with a bad 3" exhaust, factory cams, GTS-R manifold.

Held to 8000rpm no problems (GT3040/600hp).

I wish I'd had a chance to test it with a proper 3.5" exhaust that flowed nicely, would have seen over 300rwkw without much of a fuss was the general consensus and this was what… 4 years ago now.

Ended up making 370rwkw on 104 octane/24psi. Guilty-Toy made ~350rwkw factory head with a GT35 in a 3ltr not that long after.

45ULT - most setups (RB25/30s) have all run out around the 300rwkw marker factory exhaust manifold… a few have tried to go further and not really seen much gain. I believe some of those were using GT35's are well.

Change the manifold as well and then I think there was around a 20-30rwkw gain, and nicer midrange once everything was flowing inline with requirements so perhaps have a dig in the RB30 section of the forum.

I'm all for taking stock parts to untested waters, many said for ages you couldn’t make 300rwkw on factory cams (RB25 & 26)… and now there is a good number of cars over that. Some RB26’s making 380rwkw – factory cams!

It would just seem however the RB25 exhaust manifold just don’t have much to offer. That’s not to say there is anything wrong with it. Just don’t hope for much more than 300rwkw, and if you make more then count yourself lucky (but remember a manifold change, could well offer some decent $$ vs gain improvements)

This business of welding external gate mounts to the std RB exhaust manifold raises one more possibility , welding on two mounts and keeping the divided nature of these manifolds intact .

ATP are advertising twin entry "T3" flanged turbine housings for GT30 and GT35 BB turbos so that would solve the what to hang it off issue .

I'm not sure what the worst flowing section of say an RB25s exhaust manifold is but possibly the most significant choke points could be where each set of three runners merge into the turbos twin exit mounting flange . If each of the gates could communicate with the front or rear three runners you may coax a bit more than 30 out of a 25 with a GT3076R .

Not as good as a purpose built manifold but food for thought .

Cheers A .

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Well one day the plan is to buy a ETM or 6boost manifold and tial wastegate and run that as my setup.

im starting to wonder if im losing power/torque due to running the greddy copy plenum? maybe go back to stock inlet?

on the road the car pulls nice. 2nd gear is a waste of time it comes on hard bout 4200 and spins straight to limiter 3rd has a nice pull aswell, havent been into 4th yet.

overall happy with the feel/power so far. but i know ill get use to it real quick.

be nice to get some mt street slicks and run it at the track

Edited by l0WRB
  • 4 weeks later...

yeh i got mine all tuned and finished and came out with the same results as justin..

i find the car to be laggy for street use..

but have a track day this monday and will c how she goes there...

but i still love it..

yeah after last 3-4 weeks driving

290kw feels like 180kw now haha no matter what your always gonna want more.

my mates rb25 with gt3082 .63 got tuned other day and made 286kw on 17psi and it feels stronger then mine, he is still running factory inlet manifold but a highmount setup, feels so strong, yet mine makes more torque and power onyl by like 4kw lol

once colder weather comes in, im going to take it to test n tune and try beat my old 114mph trap speed.. hopefully 118-120 would be nice but i doubt it haha

Edited by l0WRB

mines laggier then the 3082 might be because he is running .63 rear and im running .82.. he is seeing 17-18psi by around 3800-4000rpm

im seeing 19-20psi around 4100rpm

yeh on the street its not a bad setup still responsive but it doesnt give u that WOW factor like a 400rwhp aggressive turbo would. although i really need decent tread (just run stock 16" rims with 225 federals) because 1st/2nd gears its just wheel spins therefor i cant even feel the torque, but my mates has 255 on 9" wide nismo rims and it just grips in 1st and 2nd and pulls like a train

might just be me, every car i go in always feels better then what you drive. id love 2 ditch the stock manifold i really would.

Edited by l0WRB

Very good result. I got a internally gated 3076r .82. Running standard manifold and standard inlet manifold. Still got the cat in there too. Making 280rwkw @ 17 psi. Will get a new exhaust manifold and a de-cat so should see close to 300kw soon. See how it goes

mines laggier then the 3082 might be because he is running .63 rear and im running .82.. he is seeing 17-18psi by around 3800-4000rpm

im seeing 19-20psi around 4100rpm

yeh on the street its not a bad setup still responsive but it doesnt give u that WOW factor like a 400rwhp aggressive turbo would. although i really need decent tread (just run stock 16" rims with 225 federals) because 1st/2nd gears its just wheel spins therefor i cant even feel the torque, but my mates has 255 on 9" wide nismo rims and it just grips in 1st and 2nd and pulls like a train

might just be me, every car i go in always feels better then what you drive. id love 2 ditch the stock manifold i really would.

if you can get a copy of his dyno sheet post it up.

by the WOW factor do you mean the sudden hit of boost by a larger turbo?

not really sure what your after, it spins the tyres in 2nd from 4200rpm to redline lol thats what i want :D

it sounds to me like 300rwkw is never going to make you happy. go buy a new LS3 V8 and turbo that :D

Edited by Harey

hahaha.

but i am correct 300kw now days is like 200kw 5yrs ago, it felt fast but u get over it real quick

i went for a drive in mates 32 with rb25/3582r made 471rwhp and that feels quick alot quicker then 390rwhp haha 3/4th gears just rev out instantly where as with mine u gotta watch it rev :D

mate it aint even fast lol trust me. you will keep up.

think all us boys heading up towards winter to race every car of ours will have over 300kw one will have 500kw haha should be fun :D

Edited by l0WRB
hahaha.

but i am correct 300kw now days is like 200kw 5yrs ago, it felt fast but u get over it real quick

i went for a drive in mates 32 with rb25/3582r made 471rwhp and that feels quick alot quicker then 390rwhp haha 3/4th gears just rev out instantly where as with mine u gotta watch it rev :cool:

Its all about power to weight. Thats another reason why the R32 would have felt faster, not to mention the extra 80rwhp :ermm:.

I think its also about expectations, I wonder if you would be happy with 350rwkw or still want more haha.

mate id love to have the setup you do.

Honestly tho running that power through stock rims? get some wider rims an put some 255s or wider on it.

An yeah by the sounds of it you need just a lil more power an you may be happy lol.

Either that or your a power broad minded person thats never satisfied lol.

mate id love to have the setup you do.

Honestly tho running that power through stock rims? get some wider rims an put some 255s or wider on it.

An yeah by the sounds of it you need just a lil more power an you may be happy lol.

Either that or your a power broad minded person thats never satisfied lol.

Lol ok i guess you cant say that word i wanted to call you on here haha.

broad minded person indeed lol :cool:

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