Low resistance exhaust sytem for the MGB ?

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mgbv8
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Low resistance exhaust sytem for the MGB ?

Post by mgbv8 »

I dont think I can do much more to reduce exhaust resistance now?

1 3/4" primaries about 16" long.
Flanges and gaskets hogged out to match the port size.

Still not sure where to place the lambda bungs and EGT bungs though?

I've only got about 6" of pipe from port to just under the bonnet line now.
Trial fit just completed so I can sort out what needs to be moved out of the way. Test fire tomorrow evening when I'm back from Xmas shopping with the wife :lol:

Image


Perry Stephenson
MGB GT + Rover V8
9.62 @ 137.37mph
Now looking for 8 seconds with a SBC engine
http://www.youtube.com/watch?v=nVscbPHgue0&list=UUqIlXfSAoiZ--GyG4tfRrjw

https://www.youtube.com/watch?v=eg3avnsNKrc&index=2&list=FLqIlXfSAoiZ--GyG4tfRrjw
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topcatcustom
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Post by topcatcustom »

Don't think there is much more to lose there Pel! So long as you have a generous radius on the bends.
TC
mgbv8
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Post by mgbv8 »

A better pic and now a vid !!

Image


http://www.youtube.com/watch?v=jEML7-9Fpsw&feature=youtu.be
Perry Stephenson
MGB GT + Rover V8
9.62 @ 137.37mph
Now looking for 8 seconds with a SBC engine
http://www.youtube.com/watch?v=nVscbPHgue0&list=UUqIlXfSAoiZ--GyG4tfRrjw

https://www.youtube.com/watch?v=eg3avnsNKrc&index=2&list=FLqIlXfSAoiZ--GyG4tfRrjw
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JSF55
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Post by JSF55 »

Plus .....added downforce for the front end :lol:
So thats where it went !
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Blown v8
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Post by Blown v8 »

Sounds awesome
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Post by ChrisJC »

It will be interesting to see if it improves the times.

Chris.
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Post by Quagmire »

That is loud! How do you guys have any hearing left? Especially Perry! :lol: :lol:

Cool though 8-)
1974 Rover 3500s
1984 3.5 90
1959 2.25 series 2
mgbv8
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Post by mgbv8 »

ChrisJC wrote:It will be interesting to see if it improves the times.

Chris.

I wont know how this improves engine output as I dont think my Dyno guy will want it on the rollers with these pipes. My guess would be 20hp ish ?

This is one of a few mods going on over the winter. Other mods are a transbrake in the gearbox + wheelie bars. I'm hoping the overall effect of the mods when I have learnt how to use them will be 0.2 of a second on the existing engine tune. And then 0.4 of a second on the new engine tune which I will be adding over the early part of next year?
Perry Stephenson
MGB GT + Rover V8
9.62 @ 137.37mph
Now looking for 8 seconds with a SBC engine
http://www.youtube.com/watch?v=nVscbPHgue0&list=UUqIlXfSAoiZ--GyG4tfRrjw

https://www.youtube.com/watch?v=eg3avnsNKrc&index=2&list=FLqIlXfSAoiZ--GyG4tfRrjw
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Post by chodjinn »

wow, that sounds awesome mate!
RIP MGB V8 .... served me well as a learning curve.

R32 Skyline V8 .... this one is gonna be a monster!
mgbv8
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Post by mgbv8 »

Final fitting now done thanks to Mike, Tricky, Jason, JJ, Nige and Dan.

Today was the intervention that I had been forced to attend by Tricky. The lads had made it quite clear that I would get duffed up if I didnt get the front legs of the roll cage welded in onto spreader plates.

My Truck is broken so Mike (Kiwicar) came over and hauled the trailer over to Trickys workshop.

So while Jason got busy with the welding I got busy with the Zoomies while Mike and the others helped out in various ways on the car.

I made sure that everyone had pasties and mars bars and drinks :)

I should have the truck back from repair on Monday so Monday will see me on the local industrial estate giving the engine some revs on the pipes which are now port matched to the heads. The previous video was with the header flanges at stock size of about 22mm wide port size. My heads are 28mm wide on the exhaust ports + a few mm higher as well.

I'm going to get a mate to laser cut some frames to go around the holes in the bonnet out of stainless steel to tidy them up.

As you can see in the picture, the weather proofing for the pipes has also been completed :)

Image
Perry Stephenson
MGB GT + Rover V8
9.62 @ 137.37mph
Now looking for 8 seconds with a SBC engine
http://www.youtube.com/watch?v=nVscbPHgue0&list=UUqIlXfSAoiZ--GyG4tfRrjw

https://www.youtube.com/watch?v=eg3avnsNKrc&index=2&list=FLqIlXfSAoiZ--GyG4tfRrjw
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Post by r2d2hp »

Pel, have you tried starting it with the tennis balls still on the exhaust. Must get a video if you do
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Post by mgbv8 »

r2d2hp wrote:Pel, have you tried starting it with the tennis balls still on the exhaust. Must get a video if you do

Its on the TO DO list for next year Reg ??
Perry Stephenson
MGB GT + Rover V8
9.62 @ 137.37mph
Now looking for 8 seconds with a SBC engine
http://www.youtube.com/watch?v=nVscbPHgue0&list=UUqIlXfSAoiZ--GyG4tfRrjw

https://www.youtube.com/watch?v=eg3avnsNKrc&index=2&list=FLqIlXfSAoiZ--GyG4tfRrjw
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Post by kiwicar »

Hi Reg
are you coming out to play some time over the holiday period. . . :D :D :D
I have some more roller rockers going cheap!
Best regards
Mike
poppet valves rule!
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Re: Low resistance exhaust sytem for the MGB ?

Post by Eliot »

mgbv8 wrote: Still not sure where to place the lambda bungs and EGT bungs though?
http://wbo2.com/lsu/lsuinstal.pdf
Suggests 12" on a single runner - more if you have the space and to ignore the readings at idle as it will mostly be fresh air.
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Post by Darkspeed »

Thanks for posting that Eliot really useful document - I think I will be making up one of those sniffer pipes up as I can see one of them being quite useful. Would one of those not be the ideal solution for you Perry ? - gives the option to just drop it in each runner individually. Make the inlet small bore tube a bend to get it out of the firing line.
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