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short runner intake


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Hi all

As I slowly collect the parts to turbo my car I have hit a slack point and I am thinking about building my short runner intake manifold. I have a few questions though....

1. Is there a desired pipe diameter for the manifold....5,6,7"

2. what side should the throttle body be on. I plan to fit it to the left hand side but have seen some on the right hand side...

3. Can I test it on my stock N/A engine....or will I lose power/torque.....

Sorry for all the questions..

Cheers

Ryan

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I cannot answer your first on second question but I have been told by the vr6specialist here in holland that running a short runner without a turbo or charger will lower your torque , however they didnt mention anything about horspower .

Hope that helps.

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no it wont , a short runner will not give you 20bhp ..

uter crap

in forced induction cars they do work , but most shift the optimum trq range and bhp point.

imho, they are a waste of money , when the standard mainfold flows perfectly well.

they argument of better pipework run is also tish , as unless you buy a pukka 600/700 pound one , it never fits .

but a proper turbo manifold and get some 2.5" intercooler pipework, for most people that wil be enough .

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so its a waste of time really.....I take it if it is fitted to a N/A car then I will lose bottom end torque...I am stuck the now as I have started to collect parts for the conversion but can't decide if I should stay N/A or go charged....The car is going to be used on track and twisty a/b roads with a 3.6fd. The situation the now is do I go and get the spare engine I have lightened and balanced with a flowed head, some cams, six branch manifold or do I stick a nice turbo on it......

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It's not a waste of money at all. Schimmel's sri DOES give 20hp. I ran it on my standard engine before going turbo and it made 40hp more with an s/c compared to the stock inlet.

With boost the standard intake restricts the flow, both in 12 and 24v applications. They restrict top end power in nasp applications too.

I can't speak of non schimmel intakes though but most of the ebay specials i've seen look shit.

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sorry i just dont see how its worth it on a N/A car.

the do shift the trq point , and yes the do flow better higher up , but for a money v trq/power gain , imho it isnt worth it .

at the point you have done cams, filter, exhaust and 6 branch on a vr6 , had a remap done , i think you are at a point were the only sensible option is forced induction .

i made good power on my old vr6 turbo , and yes it did drop trq over the last 1000 revs, but nothing that i noticed and nothing that warrented a 600/800 pounds outlay ..

i tend to weigh performance items up in trq/power v money spent gains .

with this in mind , the sri comes towards the bottom of my list .

agreed all the ebay ones ive seen , and helped fit are of poor orientation , the welds etc look ok, but i doubt they flow to well .

meaning that in this instance buy the best you can , so 600-800 for a 12v unit and around 1000 for a 24v application .

this of course is only my opinon .

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I have been looking into it a bit further and to be honest its a bit more complicated than I thought. i was planning to fabricate my own but after reading on vortex I would have to take into account the difference in runner lengths so that the rear bank of cylinder don't run lean. It apparently can be sorted by adjusting the fuelling on the ecu map though. I had planned to keep the lower section and then cut the upper section and fix the new inlet manifold to that.

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Agreed Jim, wasn't trying to cause a big debate or anything!

A short runner on an otherwise standard car I agree won't be to many people's liking, but if you have the 3.6 final drive and cams etc, it's a completely different engine and one people would love in the mid to top end :-)

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I have been looking into it a bit further and to be honest its a bit more complicated than I thought. i was planning to fabricate my own but after reading on vortex I would have to take into account the difference in runner lengths so that the rear bank of cylinder don't run lean. It apparently can be sorted by adjusting the fuelling on the ecu map though. I had planned to keep the lower section and then cut the upper section and fix the new inlet manifold to that.

That only becomes a problem at big boost pressures but Schimmel had no issues with lean running at 40psi boost with a 3% compensation on the back bank. All 6 of my plugs were the same colour @ 1 bar with his SRI. You would normally see sootier plugs where there is an airflow imbalance. Injector quality has a lot to do with it as well.

Injectors that atmosie quickly and get into the air stream are far better than those that just wash the intake walls.

I would stick to the standard inlet for now and see how that goes. If you feel you need more top end flow, you can swap to an SRI a bit further down the line.

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i knew that kev :)

my point was / is , as you have said on a otherstandard car it isnt worth it.

most people will not pay for a properly engineered item , they simply look at the cost and think i can do that for say 500 pounds less.. its the time that goes into developing that you end up paying for . quite often the manufacturing cost is secondary to the develpment time.

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