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View Full Version : Four branch manifold fitment


1chiz
29-10-10, 03:49 PM
Hi all,

I was wondering if there is a difference between the fitment of a four branch exhaust manifold for a 1400cc and a 1300cc? I.e are the bolt patterns the same?

Cheers
mowgli
29-10-10, 04:07 PM
should be the same, what is up with it?
C612DNM
29-10-10, 04:09 PM
Bolt patterns are the same. Port shame *may* be different.

Some (many!) 4-branch manifolds are less efficient than the factory cast manifolds = power down the drain.

Having done a lot of rolling road tests in years gone by, the only one that really does work is the BTB 4:1
mowgli
29-10-10, 04:17 PM
loads appear on eBay, and make crazy money... they all look the same externally, but god knows what the 4:1 shape is like inside...

someone had trouble with the flange needing cutting on one the other week to make it fit.
1chiz
30-10-10, 04:29 PM
Cheers guys,

I have just got a new exhaust system (from the manifold back) and thought i might as well get a four branch and fit them both at the same time. The one i was looking at was on the bay item number: 170556837452. It is stainless steel as i wouldnt bother with a mild steel one, it doesn't say who made it but it says it was off a 1400 and i was curious if it would fit my 1300sr.

Also what is a BTB 4:1? And my current cast manifold has a plate type thing attached which supplies hot air to the airbox for cold start help i think, so what happens to it if you fit an aftermarket unit?

Thanks in advance guys!
paul james
30-10-10, 05:16 PM
In my experience the standard 1.3 exhaust manifold is better.
C612DNM
30-10-10, 05:51 PM
BTB is a specialist exhaust manufacturer near Daventry. Joe Ellis (the guy who owns it) used to race a Nova years back.

Most 4:1 manifolds, that have the four pipes lined up side-by-side are pants, some are worse than pants! I had an Ashley one on my 1300 back in 1990, it sapped 8hp at the wheels compared to the flowed cast iron setup that I had.

If you have the skill, tools, and time, gasflowing a standard 1300 cast manifold, and getting genuine GM downpipes (aftermarket/KwikFit&Falloff) ones are crap in comparison for flow), and gasket match the whole lot (that's lots of grinding), you'll get a reasonable power increase over standard.
1chiz
31-10-10, 04:29 PM
Cheers, looks like its grinding time!
danderv
31-10-10, 08:25 PM
loads appear on eBay, and make crazy money... they all look the same externally, but god knows what the 4:1 shape is like inside...

someone had trouble with the flange needing cutting on one the other week to make it fit.
That was me and i had to cut a small triangle off the left hand lower corner so it would pull up to the head.It was an ashley one by the way.
adam c
01-11-10, 08:35 PM
BTB is a specialist exhaust manufacturer near Daventry. Joe Ellis (the guy who owns it) used to race a Nova years back.
.

Very good manifolds but when i emailed them for a replacement for my BTB manifold they said that they no longer produced the manifolds for the nova(it was for a 1600 8v that i enquired about)