jun style intake manifold


stevenEK9 said:
i run a 65mm TB on my built B18C, was advised by a very reputable company that any more would loose acceleration

car makes 206whp with a very nice shape of graph and strong torque curve, results speak for themselves

unless there was compelling evidence of some R&D for that inlet manifold i would stay clear, inlet manifolds should be designed for each application, just because it's got a massive TB opening and big runners etc doesn't mean it will all work well together.....
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I will have to disagree with you m8 as I run mine with 70 mm tb and its making 210 whp.. And a friend of mine has a b20 with 76 mm tb and its making 236whp same engineer tuned our engines
 
Time to jump on the band wagon I guess...

Mine are 60-62mm and making 215whp.. Bigger isn't better (unless your using forced induction). Just look at the old (60-85) F1 cars with the long runners with not so big tapers - and they are what 3.5-4l engines??

I'd go with common sense on this one.

I'm with steven on this, unless there is some R&D to go with it useless...
 
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ok lets ignore 80mm throttle body. if i were to fit a smaller tb with this manifold
wouldn't larger runners and plenum allow greater air flow.isn't that what we are looking for after all?
 
You are forgetting 2 items:
- Air velocity
- Air turbulence

Air velocity speaks for itself. Air turbulence is how smooth the airflow is. IIRC on lower revs you want both to be high. That way the air/fuel mix is better which means higher power and better economy. On higher revs turbulence stand in the way of maximum air delivery to the combustionchamber which means loss of power. Bigger runners also means lower velocity which may lead to loss of power on low rpm's.

Turbulence can be induced by sharp edges etc and can actually mean loss of power when there is too much of it. It can also mean loss of air velocity. It's all about the balance between the two and between low-rpm and high-rpm power. When a manifold is prdouced with bad quality unnecessary sharp edges and other things can cause a manifold to influence velocity and turbulence in a way that affects performance negatively. So no, larger plenum and larger and longer runners is certainly not per definition better.
 
I agree with you wazer and steve but its not that the smaller always has gains and bigger loosers.. Both have benefits! Its on common sense as you say!! Also matters the blueprint of the car if you can keep your air fuel mix optimal I guess your ok.. I run it rich and works great its 0.98
 
guess that all makes sense.. guess i just have to "trial and error" on these untested manifolds.
 
freewilly said:
guess that all makes sense.. guess i just have to "trial and error" on these untested manifolds.
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Well ye...it looks like you have to try it and see what will happen!! But it looks like a good one so don't worry with a smaller tb it will be ok with good gains! Let us know if you get it
 
i dont think jun makes it for b series. i know they do for 4g63 ( evo engines) and sr20's (silvia)
 
Jun makes it part by part all welded together! Its a very rare intake and it cost around 2800 usd if you find any!! Itys an awesome intake and dyno proven give almost 25 whp more than any other intake!!! Its simillar on running itbs
 
so should i take a risk in getting a replica ( usd 500 ) together with a 80mm tb??.
i will defenataly not use the 80mm tb. probably go for super90 70mm tb.
 
Yes m8! I messaged the topsoundperformance team for that intake and asked them if there's any reviews about the product or any proof it works and they said its a high quality product quaranteed to give much gains from 7000 rpm to 10000 rpm!
 
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