Na inlet manifold or the square turbo one?

na runners are better as for the top half... ****s me

Turbo manifold was designed with low end torque in mind, which is why it has less CFM than NA manifold, you would think that would make the NA manifold better, but to be honest, how many 10 sec VLs still use the NA manifold? Whereas the forward facing turbo manifold is a maatouks proven item.

most aftermarket manifolds use the nNA rnners. eg nizpro, JD custom

Quote: Originally Posted by pro747 [View Post] most aftermarket manifolds use the nNA rnners. eg nizpro, JD custom thats true. longer runners apparently offer more torque and the larger plenum chamber offers larger volumes of airflow which a large turbo will easily force in to occupy the bigger space. also i dont think the na bottom half fits up to the turbo top half last time i had a look.

That sounds about right n/a runners don't bolt to turbo top halves and vice versa. n/a plenums apparently have a more even distribution of airflow to each cylinder.. My Rajab upper half on n/a runners seems to work rather nicely with my gt35 9.9@134mph If I didnt buy a Rajab plenum and was on a serious budget I'd do a forward facing modified n/a top half. There's something much like this on eBay for around 400ish dollars and it's pretty well presented. Some original photos have not been recovered yet.

Quote: Originally Posted by pro747 [View Post] most aftermarket manifolds use the nNA rnners. eg nizpro, JD custom Personally I would say that this is because the n/a runners are far more common than the turbo runners. Im tipping thats the only reason too. Want the best? Buy Hypertune.

Quote: Originally Posted by 88 Chaser [View Post] Personally I would say that this is because the n/a runners are far more common than the turbo runners. Im tipping thats the only reason too. Want the best? Buy Hypertune. also because of the old high rise manifold theory on the v8s longer runners stop blow back creating an 'easier' idle and they also flow betyer then the turbo manifolds (well so its been rumered

Wouldnt a hypertune be way too much volume/CFM for a stock VLT? kinda like the JPC manifolds

i believe inlet manifold design revolves largely around the runner design, not the chamber itself. So any plenum, which uses aftermarket runners, like JPC/CPC/SPP etc, will always work better than a plenum with standard GM RB30 runners.

id like to clear some things up alittle here longer na runners are better for torque and shorter vlt runners are better for top end. short and fat top end, skinny and long for torque thats the facts jack. although the na runners do look like there more equal in length

Quote: Originally Posted by vh sle rb [View Post] id like to clear some things up alittle here longer na runners are better for torque and shorter vlt runners are better for top end. short and fat top end, skinny and long for torque thats the facts jack. although the na runners do look like there more equal in length I was told the exact opposite from someone in the know... VLT plenums spool turbos harder than other plenums, essential for large frame turbo manual cars

yeh someone that keeps creating the fastest vls around im with ash results have proven it but if your not to worried on squeezing every last killawasp out of it go for what ever u like the look of

Cool lets just see a turbo TB42 then, easy done just grab the turbo exhaust manifold from the TD42

Quote: Originally Posted by xAsh- [View Post] I was told the exact opposite from someone in the know... VLT plenums spool turbos harder than other plenums, essential for large frame turbo manual cars lol ---------- Post added 03-06-12 at 06:00 ---------- Quote: Originally Posted by xAsh- [View Post] I was told the exact opposite from someone in the know... VLT plenums spool turbos harder than other plenums, essential for large frame turbo manual cars 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

I don't know.. that doesn't make much sense to me. The Rajab plenum has been used on their own racecar well into the 8s, as for the Nizpro plenum, I don't think I've seen it used on an 8 second car. The SPP plenum would be over 3ltr in capacity I think, it's massive. What you have said about the runners is what I have heard too.

out of all the rb series motors that are used by the big boys in the drag racing scene there is only 1 rb motor that can run insane numbers with 100% stock standard factory intake runners and plenum and you guest it! the rb26. thay run short large diameter runners and a plenum chamber volume closer to its capacity. my point how many rb20,25,30,s running those kind of times use 100% stock standard factory intake runners and plenum? none that i have seen. the rb30 suffers from harmonic vibrations at around 7,500-8,000rpm now to get into that would take for ever but by balancing it right and using the right mix of parts you can move the rpm thresh hold up a tad. that is why the factory runners are used on rb30,s weather its na or turbo runners. using say a rajab cast plenum with na runners means you get a good even length runner with a strong durable cast plenum with its forward facing throttle body position its a good street set-up and the best part is that the rajab plenum is made out of cast alloy not sheet metal which means it wont crack at the welds over a long period of time, now the reason thay most likely used the na runners is because thay are more equal in length and the fact that thay wouldnt be able to use trumpets inside the cast plenum to make the turbo runners equal in length! ok so now thats out of the way lets look at the nizpro/bresciani plenum style set-up thay use the turbo runners that are shorter and better suited for higher rpm but because thay are not as equal in length as the na runners thay need to fit tuned length trumpets to fix that problem and because of this thay came up with a half cast plenum chamber design the top half is one piece and made out of cast alloy and thay fit the trumpets to a sheet metal floor and weld it to the top half using the shorter runners means higher rpm and there for the engine can consume closer to its 3litre werth in capacity/volume thats why thay have a larger plenum size. ---------- Post added 03-06-12 at 07:23 ---------- a few people will most likely hate me for telling you all this but thats the way it is

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.

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 engine thats what id like to know (maybe some one thats running a billet block! some people just have too much money!

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?