Merge collector

Hi guys dose any body know the size of the outlet at the end of the collector were it meets the megaphones or silencer

Regards mark
 
There are variables Mark. Cylinder capacity state of tune ect ect.

This is general , if you have a primary of 1.75" then I come out of the collector at 2" then cone up to 2.25" maybe 2.5" then into the mufflers.

A collector is like a carby it is a venturi, If you go large it reduces the gas speed in the pipe.
This will also reduce the scavenge effect.

If you do go megaphone I have notice GT40s ran open ends on the megs, try coning them back hard and fast on the end to your collector exit size it will bring the mid range back.

What I found with mufflers was a triple pass muffler gives the system length, when I went to a SS hotdog we call them in OZ it removed some length out of the system and it lost 15hp at the wheels from about 5000 on.
I coned back hard on the ends too 2" from 2.5" then ran 2" turn downs this all happens in the last 3 maybe 4".
It clawed back the 15 hp loss.
I made parts that hose clamped onto the tails that allowed me to experiment at the dyno because I knew it would lose power by changing the length.


Jim
 
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Thanks for the info jim I am just on with making the collectors now ,the motor will be a 302 stroker with a target hp of 400 so nothing to outrageous, starting to fab up some parts now and Have really enjoyed being back in the garage, I never realised just how much I missed building and this time with my son Sam, this is very different his likes are not always the same as mine so this new thing called compromise and discussion has entered in to our relationship, it's quite refreshing,,,,,,,,,,,,,I think anyway we have finished the fuel tanks ,the steering wheel we made has just landed back from being lether stitched and chassis now on the jig and should be ready about the end of January with a fair wind
Happy days
 
My son is into Japanese cars and has a race car, when we work on the cars or go to the track it has helped our relationship no end we just connect.

He is coming around on the historic cars, he loves the in car footage on youtube of the T70s
M8 and GT40s so I feel there is hope for him yet.

I did an article on making collectors on this site somewhere, you do need a mill though.

Jim
 
All ready got the mill set up jim with vertical chuck and the rotary table as per your post so many thanks for your input ,I am finding the help on the forum invaluable it is something you should all be proud of as I know it takes a lot of usually unpayed input , Sam's daily driver is a 18 year old honda accord type r vtec so I guess we have something in common ,

Regards mark
 
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