Quote:
Originally Posted by Morgz
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I disagree - if the VLT plenum was originally designed to be forward facing (which it probably would be if it included an intercooler like the RB26 from factory) - then it is more than capable of flowing enough for serious numbers as Maatouks have proven.
You can't base the success of a stock plenum and it's runner length in achieving impressive numbers when you're not comparing apples with apples to start with.. ie: The 26 has twice as many cams, and twice as many valves I would say that is more of a contributing factor to supporting hp than the length of it's runners on a manifold.
yes agreed its a fact you can still make impressive times down the quarter mile with that kind of set-up lol its pretty much a cheaper rajab set-up with out the equal length runners. as for twin cam vs sohc a fully ported sohc head would flow more like a stock twin cam head so flow would be the same ish depending on porter or porting method but a ported twin cam head not a chance thats the differance between horse power making not quarter mile times
---------- Post added 03-06-12 at 06:57 ----------
Quote:
Originally Posted by Morgz
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LOL! why would anyone do that? Just because it works on a 26 is no reason to think it'd work on a 30 considering they are NOTHING alike. Do you seriously think it'd be a great idea?
thay are alike mate but the 26 is stronger an has some tricks up its sleeves it all comes down to money and it would cost more to do to a rb30 than 26. if i had heaps of money yes i do think its a good idea and so do rips but they use 26 heads on rb30 blocks it all comes down too how much you want to re-engineer an rb30
---------- Post added 03-06-12 at 07:03 ----------
Quote:
Originally Posted by vh sle rb
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yes agreed its a fact you can still make impressive times down the quarter mile with that kind of set-up lol its pretty much a cheaper rajab set-up with out the equal length runners. as for twin cam vs sohc a fully ported sohc head would flow more like a stock twin cam head so flow would be the same ish depending on porter or porting method but a ported twin cam head not a chance thats the differance between horse power making not quarter mile times
---------- Post added 03-06-12 at 06:57 ----------
thay are alike mate but the 26 is stronger an has some tricks up its sleeves it all comes down to money and it would cost more to do to a rb30 than 26. if i had heaps of money yes i do think its a good idea and so do rips but they use 26 heads on rb30 blocks it all comes down too how much you want to re-engineer an rb30
im just trying to point out the facts thats all i really do think rips is on the money but for the people who insist on using a sohc head the sky is the limit i guess if your rich lol
Quote:
Originally Posted by vh sle rb
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lol
---------- Post added 03-06-12 at 06:00 ----------
long skinny runners are better for low end torque. Short large diameter runners are better for high rpm. So match the runners to what rpm you want to rev too and where you want your torque. As with Plenum size its a 3litre capacity engine so you wouldn't go over 3litre in volume capacity with the Plenum. For a street registered vl Turbo running into the 10's or even 9's a rajab set up is nice but for more of a drag only nizpro or even maybe jpc
Ps ask the pro's
LOL okay rajab might be alright for 9/10's thats cool, standard VLT with XF throttle body is running 7's on Georges car and 8's in Bens manual car, do you mean these pro's?
Quote:
Originally Posted by xAsh-
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LOL okay rajab might be alright for 9/10's thats cool, standard VLT with XF throttle body is running 7's on Georges car and 8's in Bens manual car, do you mean these pro's?
yeah im not saying you cant run a good time with these setups every thing that i said can be used on any engine the fact is a vl turbo with nothing more than turbo, injectors and ecu oh an exhaust, intercooler ect ect can run into the 11sec maybe even 10s so really how much harder would it be. but if you set every thing up proply you dont need to force as much boost and at the same boost levels you would make more power
Yeah thats kinda how it works, as you know the standard manifold has more low end torque due to smaller volume, longer runners, etc. That way you can run a large turbo and it spools harder than with a plenum like a JPC etc. As boost is simply a measure of backpressure in the intake system you run more boost, to see the same results as a bigger plenum, however its much lower in the rpm range. Anth put one of his cars back to back on the dyno with a brand name plenum and it make slightly more power, but not enough to justify the extra lag.
Quote:
Originally Posted by vh sle rb
[View Post]
[/COLOR]thay are alike mate but the 26 is stronger an has some tricks up its sleeves it all comes down to money and it would cost more to do to a rb30 than 26. if i had heaps of money yes i do think its a good idea and so do rips but they use 26 heads on rb30 blocks it all comes down too how much you want to re-engineer an rb30[COLOR="Silver"]
Your weren't talking about a twin cam head on a 30 block.. you were talking about an RB26 inlet manifold on a RB30 single cam head- which didn't make sense to me.
Quote:
Originally Posted by Morgz
[View Post]
Your weren't talking about a twin cam head on a 30 block.. you were talking about an RB26 inlet manifold on a RB30 single cam head- which didn't make sense to me.
no i was talking about a rb26 style set-up on a rb30 not an actual rb26 manifold on a rb30! all the other set-ups work for there given applications but in my opinion that would be the ultimate set-up.
Quote:
Originally Posted by vltgm6
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Na inlet manifold or the square turbo one?
Q: NA or Turbo manifold?
A: Both manifolds have the same heatsoak issue.
Very hard to tell the difference until a larger cam is installed.
if you want a little more than the average 7psi boost, need to plug the overpressure valve in the top half of the VLT manifold.
I prefer the NA manifold because from memory it has a little more room to R&R the injectors.
They all can make great power. The plenums, the runners, the OEM ones, all have nothing to do with big power numbers. All the big numbers come from methanol or C12 on boost numbers upwards of 30psi that doesn't even produce boost until 4000+rpm, basically lots of power in a gutted chassis.
If it's a street car, then the design is more critical than buying a plenum that the car with the fastest ET has. Even the MPH is more of a claim to fame. personally, if a car has a good reaction time, I don't even look at the ET until MPH is what I expect from the car.
Long runners, short runners, big plenum, small plenum, polished or chrome all have a different purpose.
Long runners are better for high lift long duration intake camshaft profiles(reduces adjacent port starvation due to reversion at lower rpms).
The VLT manifold short runner design combined with a low overlap camshaft is a good stock combination.
Quote:
Originally Posted by bachig24u
[View Post]
Q: NA or Turbo manifold?
A: Both manifolds have the same heatsoak issue.
Very hard to tell the difference until a larger cam is installed.
if you want a little more than the average 7psi boost, need to plug the overpressure valve in the top half of the VLT manifold.
I prefer the NA manifold because from memory it has a little more room to R&R the injectors.
They all can make great power. The plenums, the runners, the OEM ones, all have nothing to do with big power numbers. All the big numbers come from methanol or C12 on boost numbers upwards of 30psi that doesn't even produce boost until 4000+rpm, basically lots of power in a gutted chassis.
If it's a street car, then the design is more critical than buying a plenum that the car with the fastest ET has. Even the MPH is more of a claim to fame. personally, if a car has a good reaction time, I don't even look at the ET until MPH is what I expect from the car.
Long runners, short runners, big plenum, small plenum, polished or chrome all have a different purpose.
Long runners are better for high lift long duration intake camshaft profiles(reduces adjacent port starvation due to reversion at lower rpms).
The VLT manifold short runner design combined with a low overlap camshaft is a good stock combination.
very good the only thing is most people would use high lift on the intake lobs not more duration as the air is forced into the cylinder but on the exhaust side you want the valve to stay open as long as possible over lab on a turbo cam reduces the overall boost in the cylinders
Some original photos have not been recovered yet.
Quote:
Originally Posted by vh sle rb
[View Post]
now who is going to be the first to make a gt-r style runner/plenum set-up made out of cast alloy with no welds thats suited to a rb30.
Sorry I must of misread what you said..
---------- Post added 04-06-12 at 11:07 ----------
Quote:
Originally Posted by vh sle rb
[View Post]
no i was talking about a rb26 style set-up on a rb30 not an actual rb26 manifold on a rb30! all the other set-ups work for there given applications but in my opinion that would be the ultimate set-up.
lol, u may have confused yourself. I don't think a 'GT-R style' plenum with 6 butterflies on a RB30 single cam head would be worth the time of anyone to make it. They each cause a restriction in every runner, and you can see people opting for the single t/b over these in most conversions.
Some original photos have not been recovered yet.
Quote:
Originally Posted by Morgz
[View Post]
Sorry I must of misread what you said..
---------- Post added 04-06-12 at 11:07 ----------
lol, u may have confused yourself. I don't think a 'GT-R style' plenum with 6 butterflies on a RB30 single cam head would be worth the time of anyone to make it. They each cause a restriction in every runner, and you can see people opting for the single t/b over these in most conversions.
nah im pretty shore there was two versions of the gt-r manifold made mate. i could be wrong though there is one that uses the 90mm throttle body but i may be aftermarket.
Some original photos have not been recovered yet.
Greddy plenunms are similar to standard GTR but use single T/B. If i built a 26/30 i'd probably go a RIPS or hypertune plenum. Look good and perform well.
i remember seeing a photo of a rb26 head bolted to a rb30 block it had the crank removed and the photo was taken down through the cylinder walls to show the relationship between the combustion chambers and the cylinder walls from memory the combustion chambers where out by around 6mm or some thing like that. rb26 head is still a sweet idea though. i love my 2jz better though bang for buck.
