Fitting twin 3.5” Anyone make a drop tank to suit?

[Dmann 3]

Hi,

plan is to do twin 3.5” to the back hopefully over the diff.

 

Has anyone done a drop tank to narrow the fuel tank and allow some big pipes to exit the rear?

[deankxf 20,743]

on what car? 3.5 is a tight fit.. will also depend how low the car is for diff travel. 

 

[bear351c 10,356]

I once fitted an Escort tank under my XD, and ran twin 2 1/4" pipes. Dont reckon you'll get 3 1/2" pipes over the diff, without banging.

Currently have twin 3" pipes on the XB, but, running under the diff.  Thought about using a fuel cell, inside the boot.?

[Dmann 3]

Sorry, yeh its an XD.

 

I have though of fuel cell but some nce I will be cutting out spare wheel well thought I might as well make it for a drop in drop tank of about 80-100lts.

 

It will be on the street occasionally so will have to be legal as possible. I don’t think fuel cell pass do they?

[deankxf 20,743]

depends how low it is too? because on BGDAVs XE it has 3.5 inch over the diff that's been squashed to 3" at best  by the diff tube.  you might be better off going under the diff

why does it need twin 3.5" is it some humungus engine? or twin turbo monster

[Dmann 3]

Yeh under the diffs would be safer and straighter.

Motor will need some big pipes.

Plan is to Clevo NA 420-440CI CHI Pro series heads with cam in the 280deg@50thou range. Will need to rev a bit so need good flow.

[bear351c 10,356]

Guess you'll have to check local regs regarding the laws in your state. (fuel cells)  Maybe contact a local Fabrication business, or a car club for more info.?

[Thom 6,694]

My old man's a model has 540rwhp 393 clevo, it runs twin 3 inch collector's and steps down to a twin 2.5 inch with an x pipe then out of the rear of the car it made 5 more ftlbs and 3 more hp with the exhaust on than with it off so you may not need to go that big

[Dmann 3]

The increase would be from the X cross over not size of pipe.

It creates a big amount a scavenging.

 

[Thom 6,694]

The increase would be from the X cross over not size of pipe.
It creates a big amount a scavenging.
 

Correct, but with a 3 in collector and x over without any mufflers or tailpipes it made no difference power wise from the 2.5in system

[Dmann 3]

My post is not asking what size pipes to use, just what will fit around them.

Iam not sticking a 2.5” pipe on my 900hp banger. 

Its all relitive to what you are trying to achieve.

[Thom 6,694]

My post is not asking what size pipes to use, just what will fit around them.
Iam not sticking a 2.5” pipe on my 900hp banger. 
Its all relitive to what you are trying to achieve.

Sorry got sidetracked, is it worthwhile looking for an xa-xc style tank? Not sure on how difficult one would be to fit, but being narrower may help, plus some of them were long range tanks

[XF347 205]

This car had a drop tank, not sure if it was still fitted when he did the twin 3" exhaust though.

 

http://www.ozfalcon.com.au/index.php?/topic/233-xd35i-ghia/

 

 

[deankxf 20,743]

not sure if this link will work. or the second. but there's an XD with fuel cell in the boot and 2 big pipes over the diff.. 

 

https://www.facebook.com/80s-and-90s-ford-and-holden-porn-753913551355483/?__xts__[0]=68.ARDLE1Zn5wthaJaLxXcUqB1xRUOZLkcdAyvcZhyAd-fTX6BmhOzjKe1BWlDIJFIO4Xq0ofjjUFJXXsusonMCjQtBtN9vqC-u72uS4bqeLafiMYJpDmasW5HN6RYRZM3wgiodZUhLhfTo2wwNWnGLncCHA-ZY_TZM3bqqwYtmJM_VU66q88iVCdUX4Sp3-ohisaVTdGDOB0Pe29xd1aSYgPtT&__tn__=k*F&tn-str=k*F

 

https://scontent.fmel4-1.fna.fbcdn.net/v/t1.0-9/44126770_1985811264832366_6418824535063134208_n.jpg?_nc_cat=101&_nc_ht=scontent.fmel4-1.fna&oh=e3f10db28b079878570badb710b3e558&oe=5C8A79D9

[Ron 4]

I know its an old thread, but how did you go with the exhaust and tank? I've got a cover i picked up and was hoping to see if you figured out a way to have a tank and the twin exhaust?