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500kw Rb25det

Gta51

By Gta51,
in Engines & Forced Induction

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Gta51

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Hey guys

Currently making 415rwkw with a gtx3582 .82 rear housing on 27-28lb boost. What's the best way of getting close to or over 500kw? Would a bigger rear housing suffice ? If not what turbo is the next logical size up. Running a forged motor with all Nitto gear. Currently out of fuel system (single walbro 460lph) so couldn't push more , ill be adding two extra 044 fuel pumps into the mix

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Gta51 Collaborator

Gta51

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Would the biggest size tomei poncams help boost it aswell? fairly sure I have stock cams in it atm.

Cars a street car so I want to stay away from nitro meth etc loll

Im thinking a 1.06 rear housing, cams, and abit more boost should get me close to that

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R31Nismoid Grand Master

R31Nismoid

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If you have a GTX35 and only making 400-420rwkw though @ 27-28psi you've kinda got a problem... Assuming you are on E85 as well.

Should be a bit more than that. A GT35 will do 400rwkw on E85 with that amount of boost. The GTX flows more air, it should be well past it and around 440rwkw or more.

Could be a restriction somewhere or something else entirely. I'd be working out what is wrong first before going for more power/part changing.

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R31Nismoid Grand Master

R31Nismoid

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But a 500kW turbo LS is a very much more "streetable" engine than a 500kW 2.5 L RB!!

It's funny when the "400-500rwkw" street guys get asked what MPH they run, quite often it's FAR lower than what it should be.

Proof is always in the pudding there :)

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STATUS Grand Master

STATUS

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So agree with nismoid.

I remember a long time ago when this wasn't the case.

Ahh the good old days when saying you had a fast car actually meant, ummm, you actually had a fast car.

Mph will always rule the roost.

So agree with nismoid.

I remember a long time ago when this wasn't the case.

Ahh the good old days when saying you had a fast car actually meant, ummm, you actually had a fast car.

Mph will always rule the roost.

most cars cant handle it... we have high 300 cars running 9-10 then 500kw cars running 10-12s lol.... MPH is no longer an accurate SOLE indicator

perfect example

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Gta51 Collaborator

Gta51

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If you have a GTX35 and only making 400-420rwkw though @ 27-28psi you've kinda got a problem... Assuming you are on E85 as well.

Should be a bit more than that. A GT35 will do 400rwkw on E85 with that amount of boost. The GTX flows more air, it should be well past it and around 440rwkw or more.

Could be a restriction somewhere or something else entirely. I'd be working out what is wrong first before going for more power/part changing.

Stock cams and a single fuel pump limited me. Once I add another pump and cams I'll see that figure with a retune I'm fairly sure. I get what your saying though :)

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R31Nismoid Grand Master

R31Nismoid

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most cars cant handle it... we have high 300 cars running 9-10 then 500kw cars running 10-12s lol.... MPH is no longer an accurate SOLE indicator

perfect example

Yeah but in GTS-t / GT-R land - There are so many results it's pretty easy to work it out where a car should be (say +/- 3/4mph). Some cars are like 10mph down (some are up lol), that ain't a result of a car that can't handle the power. Generally from what I've seen, if you have less traction you end up with slightly higher MPH - big more bragging rights at the pub isn't necessarily a bad thing lol :)

Most R33 GTS-t owners with 300-340rwkw are around the ~127mph

R33 GT-Rs with 300-340rwkw get around the ~124mph, if it's a R32 you're a little higher as you weigh less and so on.

Of course it's never gonna be 100% accurate, but you can get in the ballpark. Same as when someone posts up their GT-R is making 370rwkw on -9s never got anymore than like 120mph... Result debunked, you didn't have 370rwkw! Not a chance.

Then there was a 450rwkw 33 GT-R recently in NSW I saw that I think was like 124/125mph. Even without doing a big launch, something ain't right, it should be over 130mph easy.. Either it didn't have the power on the night or someone was singing hey diddle diddle in the dyno room

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R31Nismoid Grand Master

R31Nismoid

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Stock cams and a single fuel pump limited me. Once I add another pump and cams I'll see that figure with a retune I'm fairly sure. I get what your saying though :)

I had a big post for ya and my internet died lol. Poop.

Anyway I think fix the fuel pump and then see? It's pretty easy to do... IMO you should've run outta fuel before you got to 28psi. That's a LOT of pressure/flow needed outta the pump. Guys here on PULP have made ~370rwkw with a GT35 and stock RB25 head (around the 22psi marker). Then to get the 400 E85 and a bit more boost, and that's a smaller huffer and you really are running some good boost.

I mean look it might be nothing, or maybe you'll find 30rwkw easy just getting the fuel it needs? Even something simple like dropping the exhaust at the dump/cat you might just pick up 30rwkw. Sometimes even with a little restriction a set-up can still perform very well, just not perfectly type thing.

Obviously with head/cams etc you will potentially make more but something currently just doesn't sound right if you know what I mean? I'd be sorting the bits around it and checking a couple things first if you haven't already

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XGTRX Veteran

XGTRX

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most cars cant handle it... we have high 300 cars running 9-10 then 500kw cars running 10-12s lol.... MPH is no longer an accurate SOLE indicator

perfect example

https://youtu.be/Po10g8VGKTI

ETs have always indicated setup, MPH have always indicated power

Nothing has changed.

Dynos lie, MPH don't.

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Gta51 Collaborator

Gta51

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I had a big post for ya and my internet died lol. Poop.

Anyway I think fix the fuel pump and then see? It's pretty easy to do... IMO you should've run outta fuel before you got to 28psi. That's a LOT of pressure/flow needed outta the pump. Guys here on PULP have made ~370rwkw with a GT35 and stock RB25 head (around the 22psi marker). Then to get the 400 E85 and a bit more boost, and that's a smaller huffer and you really are running some good boost.

I mean look it might be nothing, or maybe you'll find 30rwkw easy just getting the fuel it needs? Even something simple like dropping the exhaust at the dump/cat you might just pick up 30rwkw. Sometimes even with a little restriction a set-up can still perform very well, just not perfectly type thing.

Obviously with head/cams etc you will potentially make more but something currently just doesn't sound right if you know what I mean? I'd be sorting the bits around it and checking a couple things first if you haven't already

Spot on fuel pump was the biggest limiting factor for me. So I'm going to add another Walbro or two 044 pumps. Might aswell add cams since I'm getting retuned, always wanted to do that anyway

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