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Minimum lenght of intake manifold for DCOE.

Posted: June 20th, 2016, 8:48 am
by Piotrek125p
Hello.

Dear GC, could you tell me which lenght is minimum for intake manifold lenght for 45 DCOE in my spec. 2L TC ? The whole spec. of my engine you have here. The excepted output that I want to get it was also placed in thread below.

viewtopic.php?f=13&t=3377

I want to make a 2.75" manifold, but after first test it will be a very complicated to make and fit in a really tidy 125p engine bay, especially if I want to make also a sealed cold air intake system.

I made some 3D models of DCOE flange, cylinderhead flange etc., I will share with you and members soon.

Thanks.
Piotrek.

Re: Minimum lenght of intake manifold for DCOE.

Posted: June 20th, 2016, 10:23 am
by Guy Croft
it depends on two principal things:

1. The length of the exhaust primary pipes - this is quite critical..
2. Where you want the torque and power

G

Re: Minimum lenght of intake manifold for DCOE.

Posted: June 20th, 2016, 10:37 am
by Piotrek125p
Exhaust header - 38mm inside, 33-36" lenght
Power about 170bhp - 7000-7200 rpm.

Rest of spec. here
viewtopic.php?f=13&t=3377

Re: Minimum lenght of intake manifold for DCOE.

Posted: June 20th, 2016, 10:46 am
by Guy Croft
with that header you can make the inlet manifold any length you want..

G

Re: Minimum lenght of intake manifold for DCOE.

Posted: June 20th, 2016, 11:03 am
by Piotrek125p
Ok, so I will make it as long as possible (it will be a slighlty offset to get extra lenght).

About airbox and rampipes, I think I will go the same way as S&B125
TENGTOP.JPG
TENGTOP.JPG (53.37 KiB) Viewed 27475 times
Thanks GC for your answer.

Re: Minimum lenght of intake manifold for DCOE.

Posted: June 20th, 2016, 11:29 am
by Guy Croft
You will HAVE to use a sealed airbox with remote filter to cold air or it will probably detonate..

most people ask, 'can't I (just) use a bonnet scoop..?'

My answer is I do not know. It is a big risk if it doesn't work..

G

Re: Minimum lenght of intake manifold for DCOE.

Posted: June 20th, 2016, 11:59 am
by Piotrek125p
I only showed how I want to solve a problem with space for airbox end, it will be of corse sealed air intake system.

I saw a lot of rally/race TC with only "net" type filters on a rampipes and owners didn't know what they have problems with detonate and head gasket failures. I want to avoid it as most as I can, but a very limited space for intake system is a real problem, but I think I will solve it with your help.