Richard Longman 306 Btcc Manifold Spec?

[markw 1]

I want to get an exhaust manifold and full system built for my xu9j4rs sprint car, currently makes 220bhp at 7200 prom on a standard 6 manifold and 2" system, does anyone have the spec on the old 396 Btcc

Manifolds, eg pipe diameter, primary and secondary lengths etc etc, just want to compare with what we have calculated.

And do you think we would gain enough bhp for the £1000 outlay, would we gain 10bhp??

Thanks

Mark

[markw 1]

I found the spec in the spoox website for their 306 kitcar s/s manifold is that a copy of the Longman manifold.

 

 

1 7/8" primarys, 2 1/8" secondaries, and 2.5" collector.

[rallyeash 155]

Sounds right. Speak to Maniflow. They sell a 'works' manifold on their website I believe. You'll want a 2.5 system yes.

 

From memory you want 12-14" length on secondaries

Actually I could measure mine haha

[markw 1]

Ash, thanks for the heads up that is exactly the same picture as spooks use, and maniflow are cheaper although they don't

Advertise the st/st version, the mild steel is still £70 cheaper than spooks.

[welshpug 1,657]

you are better off getting something made to the spec of your engine.

[Miles 331 1 Cars]

Most of spoox stuff is from Longman and has nothing to do with any kitcar as they used even more expensive parts, Unless you go custom fit is well I leave that upto you to decide.

The Race spec 4-2-1 on my 306 works a treat, Fitting into a 205 thou needs a fair amount of bulkhead mods

[kyepan 291]

The full BTCC spec manifolds for the xu9j4 are actually nearer 23 inches for the primaries from the back of the valve to the collector. Did the 306 ever race btcc?

 

The lengths mentioned above are nearer to the off the shelf maniflow type.

 

 

Cheers

Justin

[welshpug 1,657]

yep, 306 was group n spec iirc, so not that wild on engine, 240 ish bhp single throttle.

[markw 1]

Miles,

I did speak to Matt @ Simpson race exahusts but they want £1600inc vat for a one off manifold and exhaust

Which is toooo much money, my 205 already has a baulkhead mod done, would the "race" fanimold nead more

Baulkhead Modifying you think.

Any idea what power gain I should get over the std manifold and 2" exhaust?

Thanks

Mark

[petert 586]

1 7/8" - big primaries. There's plenty of exhaust calculators on-line. Is that number correct for a 500cc cylinder @ 8000?

[welshpug 1,657]

https://m.facebook.com/Edwardsmotorsport37/

 

he'll sort you out.

[petert 586]

http://www.mezporting.com/exhaust_length.html

 

It's fun playing with the numbers.