Fins on back of Valve & Fins pre TB

[immortality]

The NRE manifold lacks dual runner lenghts... but is a wicked bit of kit

Should we hone in on a purpose for a new manifold? Street engine, full blown race engine or economy motor? The NRE manifold would suit high reving engines more than low down torque (which is what most of us need/want for the street) An inlet manifold for the track would be easy, short, large runners.

An inlet manifold that produces the broadest torque range is what design I believe we should focus on... What does everyone think?

Somebody went through this years ago and came to the conclusion that the stock ecotec manifold was actually fairly bloody good at producing the best torque curve over the widest rpm band. Personally, I find that hard to believe (the MACE bits prove that) however has anybody had a look at the US OEM factory banana type manifolds used on the ecotec and 3800 V6 engines?

I'm led to believe that the older 3800 V6 US banana manifold was a decent bit of kit but the later ecotec one wasn't because it lacked runner length compared to the earlier model. OVer the years a number of our ecotec manifold have been sent to the US and the owners have said our manifolds work better than theirs.

The biggest issue I see is that most people who are making manifolds use the OEM ecotec LIM which means the runner lengths and diameter are already pre-set.

[TdracerTd]

I think there would be a lot to be said for getting the coolant galleries in the manifold as isolated as possible from the plenum and runners. Like in that twin TB one on the previous page. Although, after some discussion with a mate on the weekend, I would do it differently from that.

[immortality]

If I was to make a custom manifold I would use a remote inline thermostat housing and then a couple of braided hoses that screw into the manifold directly over the coolant gallary.

I did some logging on a Holden 355 at the drag strip and intake temps seem to be tied to engine coolant temps it's definitely something you want to avoid at all costs.

[TdracerTd]

Yep, that was what my mate and I discussed.

[vlad01]

The NRE manifold lacks dual runner lenghts... but is a wicked bit of kit

Should we hone in on a purpose for a new manifold? Street engine, full blown race engine or economy motor? The NRE manifold would suit high reving engines more than low down torque (which is what most of us need/want for the street) An inlet manifold for the track would be easy, short, large runners.

An inlet manifold that produces the broadest torque range is what design I believe we should focus on... What does everyone think?

The NRE manifold already does this. Just look at their results, the engine have extremely flat and board curves with their manifold with not all the high revs, like 3-6k the torque stays very much the same. The runners might be short but they need to be as long as the engine wants rather than what we want


I agree we need a manifold that allows the broadest curve, square area under torque and power curves is where its at.

the broader and larger this area, the more usable rpm range and torque we have, which results the fastest accelerating car in variety of engine conditions. Peaky engines only accelerate good in the peak areas this needing heaps of gears and close ratio to be able to stay in the power band all the time to make the car any good.

[vlad01]

greenfoam aka Jason while back calculated that the pre ecotec do benefit from longer runners a fair bit. They are very short to the point they hurt power.

I might also point out the the LN3 (vn s1) engine had manifolds with shorter runners than even the VP-VR.

the LN3 manifold was the same as USA ones more or less. However the VP onward was unique to Oz as the US went to banana style for those engines.

[VL400]

The NRE manifold already does this. Just look at their results, the engine have extremely flat and board curves with their manifold with not all the high revs, like 3-6k the torque stays very much the same. The runners might be short but they need to be as long as the engine wants rather than what we want

Cubes and boost seems to help with the torque curve for NRE. As most are realising a one size fits all manifold is no easy task

On the 1UZ in my car the lower intake restricts high RPM due to runner length, a few have been playing with a short runner replacement and it looked promising on boosted setups for gains everywhere. NA might be a different story.

The later models use a variable length banana style .. http://www.toymods.org.au/forums/thread ... ottle-body

[Gareth]

The NRE manifold already does this. Just look at their results, the engine have extremely flat and board curves with their manifold with not all the high revs, like 3-6k the torque stays very much the same. The runners might be short but they need to be as long as the engine wants rather than what we want

I recon the power results are more to do with cubic capacity and rod ratio than runner length, the runner seems very short in the NRE manifold = more suited to high rpm...

As immortality pointed out, the US manifolds are crap, I sold dozens of aus manifolds to the states years ago on ebay...

Anyway, i really like the prancing horse manifold a few pages back, if you have ever driven one, you'd agree that they seem to have limitless torque, Im aware that there is more to the sucess of these engine than an inlet manifold but this would be a good start, doesn't seem to be anyone else that has played with dual runner V6's either so my idea is to take two upper plenums from an ecotec, throttle bodies facing out either side, cut all the runners off the base of one manifold, build custom piping connecting twelve inlet ducts, two per cylinder arranged the same way as the prancing horse one, easy... Now just have to learn how to alloy tig properly

[Gareth]

Beat me to it vl400

[HQ355]

The NRE manifold already does this. Just look at their results, the engine have extremely flat and board curves with their manifold with not all the high revs, like 3-6k the torque stays very much the same. The runners might be short but they need to be as long as the engine wants rather than what we want

I recon the power results are more to do with cubic capacity and rod ratio than runner length, the runner seems very short in the NRE manifold = more suited to high rpm...

As immortality pointed out, the US manifolds are crap, I sold dozens of aus manifolds to the states years ago on ebay...

Anyway, i really like the prancing horse manifold a few pages back, if you have ever driven one, you'd agree that they seem to have limitless torque, Im aware that there is more to the sucess of these engine than an inlet manifold but this would be a good start, doesn't seem to be anyone else that has played with dual runner V6's either so my idea is to take two upper plenums from an ecotec, throttle bodies facing out either side, cut all the runners off the base of one manifold, build custom piping connecting twelve inlet ducts, two per cylinder arranged the same way as the prancing horse one, easy... Now just have to learn how to alloy tig properly

Alloy tig welding is easy biggvl, just gota keep everything spotless and practice on the off cuts 1st. You could allways cheat and just mig weld the alloy