Technical Big Bob

[timeless]

what is the diameter of the 899 bob?120mm?

 

[balidey]

Have a read of this old thread.
I will hopefully be making something similar next year.

https://www.fiatforum.com/cinq-sei-...-1-1-2-a.html?highlight=cinquecento+induction

 

[allanhelen]

I was looking at the bob TurboCinqy1250 did for his turbo

I like the look of it but it would need to be taller for a N/A

Has anyone looked at this in detail in terms of optimum height and the height of the entry point for the air feed?

if not is there any college guys out there looking for a project?

looking at the responses if you came up with the best design (i would suggest as nitrane one that will fit to a shortened GSR as most people have them) and did the tech drawing then there would be quite a few customers (jordan might even make then for you) if the price was right.

 

[arseofbox]

Has anyone looked at this in detail in terms of optimum height and the height of the entry point for the air feed?
if not is there any college guys out there looking for a project?

I did some work on plenum chamber design in my 3rd year at uni.

Feeding inlet and outlet perpendicular to each other isnt a good idea really as it means large exhaust: inlet pressure differentials which isnt a good thing.

Best bet is to feed from the top- theres no real optimum height as such as the air in that section isnt carrying fuel, but I am suspect on the effect of that once you inject fuel...

Id also suggest looking at an internal air stack of some description, as I found they worked very well to improve the exhaust pressure.

 

[T.E.D. Jordan]

So a direct feed via tube would be the best bet yes? direct overheadflow into the TB, as this was playing on our minds a while back as to weather it would affect fueling?

Jordan

 

[sei tan]

i made a top feeding bob from plastic plumbing parts
useing a 110mm double socket cut in half the socket
just fits over the lip on the gasket with a plywood
circle in the cut end, then a 90 degree round drain
pipe single socket pushed in a hole in the plywood
above the TB inlet this gives 60mm diameter at the
narrowest point. The setups not perfect but its made
entirely from stuff i had lying around

 

[T.E.D. Jordan]

Got pics? sounds interesting

Rallycinq - hows yours coming on? you tested it yet?

Jordan

 

[nitrane.co.uk]

Rallycinq - hows yours coming on? you tested it yet?

I suspect David's too busy unravelling OMEX spaghetti at moment

John

 

[rallycinq]

I suspect David's too busy unravelling OMEX spaghetti at moment

John

Correct, that and trying to dry out the Centaur from all the rain we have had here. I think its time to put it away for the winter.

Cheers

D

 

[sei tan]

pic

 

[Tricker...]

Every 90 degree bend on a pipe will provide the same resistans as a 10 meter long pipe - that is a basic rule in pneumatic.
The inductionkit on the picture above has two 90 degree bends meaning that the resistans is the same as in a 20 meter pipe.

When you build a inductionkit keep in mind that air will trawel the easiest way through the inlet and a inductionkit designed with soft curves on the pipes will deliver the best possible flow and best possible output.


Cheers
/Tricker

 

[randomizered]

If this is the case, maybe it a plus point for the kits that sit directly on top of the throttle body, yes they are hotter, but they are less restrictive?

Kristian

 

[sei tan]

as i said its not ideal but i cant see how a 90 degree pipe
is worse than the air entering at the side then turning 90 degrees
into the TB entrance plus the bend next to the filter is
a 62.5 degree. Combined with my 38mm TB the car realy
shifts so my £55 for induction kit and throttle body seems
like money well spent

 

[allanhelen]

So we are back to the same point

we (the royal we) still need someone willing to make to order a proven less restictive bob,

1 with an infeed of 40 mm plus (ideally 43 then it covers the max),
2 with a side infeed towards the top and smoothed to reduce turbulance
3 so it has to be taller than std
4 still must be able to fit under a standard cento hood
5 ideally use a modified gsr intake pipe
6 come complete with fixings
7 preferably nice an shiney
8 must cost less than £30

Anyone fancy being the next forum legend? just look at all those cento and punto guys out there that are potential customers

I would be willing to chip in a bit and even use my car as a test bed to help prove it if nessesary

(bit strange that oldschool hasn't picked up on this one though :yum: )

 

[rallycinq]

Apart from 'shiny' and thats why the paint is warming downstairs, I hope thats what I've got from my siamesed Bobs project.

Cheers

D

 

[bad_boy_cinq]

I had started to make one to the shape that my previous pic is. i got it fibreglassed but put it to the side and forgot about it.

 

[Tricker...]

as i said its not ideal but i cant see how a 90 degree pipe
is worse than the air entering at the side then turning 90 degrees
into the TB entrance plus the bend next to the filter is
a 62.5 degree. Combined with my 38mm TB the car realy
shifts so my £55 for induction kit and throttle body seems
like money well spent

Hi there

I think you misunderstood my intention - I was not talking down on your inductionkit, only giving some technical fact's.

My own inductionkit isn't ideal either and the one you see in my sig. is only for show and not for performance - anyway it gives my 98 bhp N/A plenty of flow, tho

This thread is about building a better induction that the one ment for the Cento 0.9 and I thought my input could make a different.


Cheers

 

[allanhelen]

If Tricker :worship: is interested in this thread then it must have legs!

there are a few people that i know on the forum that could maybe do this

Tricker
Oldschool
Jordan


any of you prepared to put some effort into this? anyone else?

I'll help wherever I can

 

[col7104]

Oldschool has seen this thread, and I was waiting for him to chip in, but I suppose I had better fill you in.

He sees no restriction with the current 899 bob design. If I recall right, the bob inlet is fine because the throttle butterfly and associated gubbins brings down the overall cross sectional area. Also the air flows fastest in the middle and this is where the butterfly and associated gubbins is, so therefore the current bob inlet should flow just fine. That was the general consensus. Whether this would still apply with a 40mm TB I don't know.

 

[T.E.D. Jordan]

im very much prepared to help you guys out, as you well know, thankyou


Im pretty sure matt would be too, seeing as hes been trying out a design of his own. Im due to get a base map for my car soon, if he has a one made by then im sure he'll be coming along to get a before and after map of it.

Jordan